WO2009105039A1 - Process for treating plant material - Google Patents

Process for treating plant material Download PDF

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Publication number
WO2009105039A1
WO2009105039A1 PCT/SG2009/000055 SG2009000055W WO2009105039A1 WO 2009105039 A1 WO2009105039 A1 WO 2009105039A1 SG 2009000055 W SG2009000055 W SG 2009000055W WO 2009105039 A1 WO2009105039 A1 WO 2009105039A1
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WO
WIPO (PCT)
Prior art keywords
plant material
process according
osmotic
immersing
root vegetable
Prior art date
Application number
PCT/SG2009/000055
Other languages
French (fr)
Inventor
Weibiao Zhou
Xiaohui Jiang
Original Assignee
National University Of Singapore
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Publication date
Application filed by National University Of Singapore filed Critical National University Of Singapore
Publication of WO2009105039A1 publication Critical patent/WO2009105039A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/08—Preserving with sugars
    • A23B7/085—Preserving with sugars in a solution of sugar
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/005—Preserving by heating
    • A23B7/0053—Preserving by heating by direct or indirect contact with heating gases or liquids
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/02—Dehydrating; Subsequent reconstitution
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/02—Dehydrating; Subsequent reconstitution
    • A23B7/022—Dehydrating; Subsequent reconstitution with addition of chemicals before or during drying, e.g. semi-moist products
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/08—Preserving with sugars
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
    • A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
    • A23L19/03—Products from fruits or vegetables; Preparation or treatment thereof consisting of whole pieces or fragments without mashing the original pieces

Definitions

  • the present invention generally relates to a process for preserving a plant material.
  • Osmotic dehydration is one of the most popular processing methods used to produce intermediate dried fruit and vegetable products or as a pre-dehydration step to produce dried products with a moisture content lower than 20% by weight.
  • Osmotic dehydration is a process used to partially remove water from food items by placing solid food, whole or in pieces, in a concentrated sugar or salt solution of high osmotic pressure.
  • the complex cell wall structure of food acts as a semi-permeable membrane where two simultaneous counter-current mass transfers take place. Specifically, (1) water flows out of the food and into the solution and (2) solute transfers from the solution into the food. At the same time, leaching of product solutes (such as sugars, acids, minerals and vitamins) into the osmotic solution also occurs. Such leaching may affect the organoleptic and nutritional cnaracteristics of product, but the amount of leaching is considered quantitatively negligible.
  • Osmotic dehydration is also referred to as solid infusion since the solid (i.e. solutes) in the osmotic solution is transferred and infused into the food matrix during the process. Osmotic dehydration has received considerable attention as a pre-treatment in varieties of dehydrated food products, especially fruits and vegetables. Using osmotic dehydration as a pre- dehydration step has several advantages such as:
  • a sugar as an osmotic agent helps to prevent collapse and shrinkage of the fruit or vegetable pieces, it often results in the agglomeration of the food product which leads to certain potentially undesirable characteristics being imparted to the fruit or vegetable pieces, such as hardening.
  • osmotic dehydration may lead to an increase in the hardness of the fruit or vegetable pieces which may make them difficult to consume and may detract from their naturally occurring hardness.
  • the fruit and vegetable products prepared by the conventional osmotic dehydration methods have improved mechanical properties and shelf- stability, such products typically have less than desirable sensory properties.
  • the final products obtain may have a "candy-like" appearance and/or undesirable taste profile (i.e. too sweet or salty) .
  • the dried products tend to have poor rehydration characteristics.
  • osmotic agents sodium chloride, sucrose, glycerol, cane molasses, corn syrup or combinations of these compounds.
  • sucrose sucrose
  • glycerol cane molasses
  • corn syrup corn syrup
  • the commonly used osmotic agents are either not naturally occurring substances or are highly refined, the products obtained therefrom can nor be considered or marketed as natural and healthy products. Therefore, it is not suitable for certain food products, such as infant foods, that must fulfill special quality requirements.
  • the conventional methods used for preparing dehydrated fruit or vegetable products do not have strict controls on the microbiological stability of the processed products, which is one of the most important factor to consider when the intended consumers are immune- compromised consumers, such as infants, elders or diseased people . Therefore, there is a need to provide a process for preparing dehydrated fruit or vegetable products that overcomes, or at least ameliorates, one or more of the disadvantages described above. In particular, there is a need to provide a process for preparing dehydrated fruit or vegetable products that are not overly hard.
  • a process for treating a plant material comprising: immersing the plant material in an osmotic solution containing an osmotic agent under conditions to at least partly infuse said osmotic agent into said plant material and release water contained therein; contacting the plant material with pressurized steam under conditions to substantially inactivate microbes in said plant material; and after said immersing and contacting steps, removing free water from said plant material.
  • the step of removing free water comprises drying the plant material.
  • the immersing step may be conducted before or after the contacting step.
  • the contacting step not only inactivates microbes from the plant material but also helps to soften the plant material tissue so that once the plant material is dried, it will not be too hard and can be easily rehydrated. Therefore, the plant material obtained from the process disclosed herein has an extremely low microbial count, attractive appearance, texture, hardness and good rehydration ability.
  • the disclosed process furtner comprises the step of drying the plant material to remove water from said plant material.
  • the osmotic agent comprises low molecular weight carbohydrates.
  • the osmotic agent may be honey.
  • the sugars present in honey are mainly disaccharides and monosaccharides: fructose (about 38.5%), glucose (about 31.0%) and small amounts of maltose, sucrose and other carbohydrates.
  • the honey solution has a higher osmotic pressure and permits ready water diffusion from the plant material to the solution.
  • single sugar solute (most commonly, sucrose) solution honey treatment has a better plasticizing effect that provides the product a non-brittle texture, and later better rehydration property.
  • a process for treating a root vegetable comprising the step of immersing the root vegetable in an osmotic solution containing an osmotic agent under conditions to at least partly infuse said osmotic agent into said root vegetable and release water contained therein.
  • the osmotic agent may be honey and the root vegetable may be a carrot.
  • a root vegetable or pumpkin at least partly infused with honey.
  • the root vegetable or pumpkin may have at least one of the following characteristics: i) is substantially free of active microbes; ii) has a moisture content of less than 20% by weight; and iii) has a crunchy texture.
  • the root vegetable is a carrot.
  • a processed plant material that is obtained from the process according to the first aspect.
  • the processed plant material is capable of adsorbing an aqueous solution or aqueous liquid, such as water, to become substantially rehydrated.
  • a method of rehydrating a plant material comprising immersing in aqueous solution or aqueous liquid, a processed plant material made in the process according to the first aspect.
  • the aqueous solution or aqueous liquid may be water.
  • the rehydrated plant material has good nutritional and sensory qualities, particularly if a natural osmotic agent such as honey is used.
  • a food package comprising a processed plant material made in the process according to the first aspect.
  • the food package may include instructions for rehydrating said plant material.
  • a pediatric food such as an infant cereal product, comprising a root vegetable or pumpkin at least partly infused with honey.
  • the root vegetable or pumpkin may have at least one of the following characteristics: i) is substantially free of active microbes; ii) has a moisture contenr of less than 20% by weight; and iii) has a crunchy texture.
  • plant material is to be interpreted broadly to include any vegetable or fruit.
  • exemplary vegetable includes root vegetables such as carrot, radish, sweet potato, turnip, potato and yam.
  • exemplary fruit includes cucurbits such as squash, pumpkin, and cucumber, tomato, eggplant, sweet pepper, spices such as allspice and chilli.
  • osmotic solution is to be interpreted broadly to include any solution containing an osmotic agent having an osmotic pressure that is not the same as that across a semi-permeable membrane so that osmosis can occur across the semi-permeable membrane.
  • the osmotic agent disclosed herein may comprise low molecular weight carbohydrates.
  • the osmotic agent disclosed herein may also comprise salt.
  • low molecular weight carbohydrates is to be interpreted broadly to include any edible carbohydrate, such as saccharide or sugar, having a molecular weight in the range of 60 to 20,000 g/mol.
  • Exemplary low molecular weight carbohydrates include monosaccharides such as glucose (dextrose) , fructose (levulose) , galactose, xylose and ribose and disaccharides such as sucrose, and combinations thereof, such as honey.
  • monosaccharides such as glucose (dextrose) , fructose (levulose) , galactose, xylose and ribose and disaccharides such as sucrose, and combinations thereof, such as honey.
  • inactivated microbes or "inactive microbes” in the context of this specification is used herein to describe killed microbes, attenuated microbes, microbes that are not capable of growing, proliferating or microbes that have lost any activity that may aberrantly cause food deterioration.
  • a population of microbes as being “inactivated” in the context of this specification, it does not mean that the whole population of microbes within the plant material are necessarily inactivated, although they may be, but means that at least 90% of the total microbe population will be inactivated. More typically, at least 95% of the total microbe population will be inactivated and yet more typically, at least 98% of the total microbe population will be inactivated.
  • the population of microbes can be determined by measuring the colony forming unit (CFU) according to methods known to those in the art. For example, if the microbial initial load is 100,000 CFU and 2000 CFU are left active after contacting with steam, tnen 98% of the microbes are inactivated.
  • CFU colony forming unit
  • active microbes refers to microbes that are not inactive microbes as described above.
  • sterilizization in the context of this specification, refers to a plant material that is undergoing treatment such that any microbes contained on said plant material become inactivated microbes, after the treatment step, as defined above.
  • sterilizized refers to a plant material has undergone sterilization as defined above.
  • crunchy texture refers to a plant material that when chewed by a person, exhibits a crisp and crunching sensation for the first of several chews.
  • microbes in the context of this specification may refer to fungi, bacteria, viruses and bacterial spores.
  • the term "about”, in the context of concentrations of components of the formulations, typically means +/- 10% of the stated value, more typically +/- 4% of the stated value, more typically ⁇ /-
  • range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.
  • the non-thermal process i.e. "osmotic dehydration”
  • the thermal process i.e. "steam treatment”
  • the osmotic dehydration step can occur eitner before or after the steam treatment step.
  • the steam treatment step not only acts as a sterilization step by effectively inactivating microbes from the plant material, it also allows for the softening of the tissues of the plant material.
  • the processed plant material obtained therefrom has excellent sensory properties, is not too hard and can be easily rehydrated, even after an air- drying has been applied.
  • the steam treatment step occurs after the osmotic dehydration step.
  • the steam used may be saturated in order to effectively transfer the amount of heat necessary to inactivate all types of microorganisms (i.e., using latent hear energy).
  • the plant material may be contacted with superheated or saturated steam of temperature from 100 to 135 degrees C under high pressure.
  • the plant material may be contacted with superheated or saturated steam of temperature of 100 degrees C for a period of from about 2 minutes to about 10 minutes.
  • the plant material may also be contacted with superneated or saturated steam of temperature of 135 degrees C for a period of less than about 3 minutes.
  • the step of contacting the plant material with the steam is at least 2.5 minutes, preferably about 2.5 minutes to 3.5 minutes. In one embodiment, the contacting will occur for about 3 minutes at 110 degrees C. In one embodiment, to inactivate microbes when the superheated or saturated steam is at a temperature of 121 degrees C, the step of contacting the plant material with the steam is at least 10 seconds, preferably about 10 seconds to 20 seconds. In one embodiment, the contacting will occur for about 14.4 seconds at 121 degrees C.
  • the step of contacting the plant material with the steam is at least 0.5 seconds, preferably about 0.5 seconds to 1 second. In one embodiment, the contacting will occur for about 0.6 seconds at 135 degrees C.
  • the sterilization step of the steam at higher temperatures, such as above 110 degrees Celsius.
  • higher temperatures such as above 110 degrees Celsius.
  • the microbes within the plant material are inactivated within a very short time. For example, if the temperature of the steam is above 121 degrees Celsius, the microbes will take less than 20 seconds to be inactivated. This short time period (less than 20 seconds) means that the plant material will not be degraded or "cooked" by the heat being supplied thereto.
  • directly contacting a relatively high temperature steam confers microbial inactivity on the plant material without compromising on the texture and nutritional value of the plant material.
  • the temperature of the steam in said contacting step is above 110 degrees Celsius, or above 115 degrees Celsius, or above 120 degrees Celsius, or above 130 degrees Celsius.
  • the contacting step results in a slightly softer plant material than what one would nave if no direct steam sterilization were performed.
  • This is particularly useful as the plant material may be made harder after osmotic dehydration.
  • the direct steam sterilization makes the plant material softer iout does not "over soften", that is, the plant material retains its original texture and crunchiness and does not have a "cooked” type texture.
  • the disclosed steaming process is different from known conventional blanching processes wnicn merely serve to deactivate the enzymes present.
  • the enzymes present in said plant material be inactivated, microbes such as Penicillium, Phytophthora , Alternaria , Botrytis , Aspergillus , Pseudomonas r Erwinia, Bacillus and Clostridium present in said plant material will also be inactivated.
  • microbes such as Penicillium, Phytophthora , Alternaria , Botrytis , Aspergillus , Pseudomonas r Erwinia, Bacillus and Clostridium present in said plant material will also be inactivated.
  • the inventors have surprisingly discovered that when the disclosed steaming process is carried out together with the disclosed osmotic dehydration and drying step, the final processed plant material achieved has superior rehydration properties, taste and texture.
  • the plant material As the microbes are inactivated by the step of contacting with steam, there is a very low active microbial count present in the plant material. This makes the plant material, being substantially free of active microbes, useful for pediatric food such as an infant cereal product. Moreover, because in one embodiment the step of contacting the plant material with high temperature steam, as described above, for a relatively short period of time, the plant material is substantially free of microbes but is not too soft in that it still has a crunchy or crisp texture. Hence, the plant material produced according to tne disclosed process is substantially free of active microbes and maintains a crunchy texture.
  • the plant material is carrot or pumpkin and the process results in a crunchy carrot or pumpkin that not only is substantially free of active microbes but also retains its nutritional integrity, color, and flavor due to the combination of the steps of immersing, contacting and removing free water steps as defined above.
  • the carrot or pumpkin that has been produced in this disclosed process may be stored for significant periods of time (such as months) without significant loss of the carrot or pumpkins' nutritional integrity, color, and flavor.
  • the overall effectiveness of the process may be determined by the combination of temperature and time, as well as the initial microorganism load on the vegetable or fruit.
  • the microorganisms associated with fresh vegetables which are rich in carbohydrates (5% or more) and low in protein (1 to 2%), come from soil, water, and other environmental sources.
  • the most common spoilage may then be caused by molds, such as Penicillium, Phytophthora , Alternaria , Botrytis and Aspergillus .
  • the bacteria species may include Pseudomonas , Erwinia , Bacillus and Clostridium. Accordingly, it may be necessary to employ a treatment period of about 1 to 10 minutes in order to obtain the desired level of microbial inactivation. Prolonged treatment may result in undesired product qualities, such as over softening and breakage of tissue structure and discoloration.
  • the osmotic dehydration step occurs after the steam treatment step.
  • the vegetable or fruit pieces may become soft and easily breakable, thus special care needs to be taken in handling the vegetable or fruit pieces.
  • the osmotic dehydration step that follows can help to strengthen the plant material tissue thereby resulting in a processed plant material having a stronger cell structure. Therefore, advantageously, the processed plant material is then more tolerant to the heating or drying process to follow.
  • the processed plant material that is obtained in accordance with the first embodiment meaning has a firmer and harder texture compared to that obtained in accordance with the second embodiment. It has been observed that upon rehydration, the processed plant material that is obtained in accordance with the first embodiment is crunchier. On the other hand, upon rehydration, the processed plant material that is obtained in accordance with the second embodiment is softer, and the time required for rehydration to achieve similar softness is comparatively shorter. Therefore, depending on the purpose of usage of the processed vegetable or fruit product., the order of the osmotic dehydration process and steam sterilization process can be alternated.
  • the order of the osmotic dehydration step and the steam treatment step does not affect the microbial stability of product. More advantageously, the risk of recontamination during the osmotic dehydration step, wnen it is preformed after tne steam sterilization step (as in accordance with the second embodiment) , is low since the high concentration osmotic solution is itself microbiologically stable.
  • the plant material are separated from the osmotic solution, washed with clean water to remove any osmotic agent that may be remaining on the surface of the plant material and drained to dry.
  • the step of further removing water from said plant material to substantially dehydrate said plant material may be a drying step. This drying step typically occurs after the osmotic dehydration and steam treatment steps.
  • the plant material has a moisture content of about 50 to 70% by weight after osmotic dehydration and at the beginning of the drying step.
  • the plant material may be spread over a pan or a belt contained within a convection oven and dried by directing a stream of hot air over the plant material.
  • the plant material may be dried at a temperature in the range of from about 30 to about 80 degrees C, preferably from about 35 to about 60 degree C. In one embodiment, the drying step is performed until a final moisture content of about 10 to 20% or a water activity of 0.30 to 0.50 is reached.
  • the drying step allows for a further reduction in the water activity and increase in the microbiological stability of the eventually obtained dehydrated plant material (which is dry and stable) .
  • the resulting dehydrated plant material has water activity comparable to those prepared by simple conventional drying techniques, while it does not have their compromised taste, color, textural or nutritional qualities.
  • the osmotic solution may be any solution having an osmotic pressure that is not the same as that within the plant material so that osmosis can occur across the cell wall, which acts as a semi-permeable membrane, of the plant material.
  • the osmotic pressure in the osmotic solution is higher than that in the plant material. Accordingly, water diffuses from the plant material into the osmotic solution while the solute infuses into the plant material.
  • the infused solute can strengthen the cell wall of the vegetable or fruit by interacting with the pectin substance in the middle lamella and filling up part of the void space created by the diffusion of water out of the plant material and changing the glass transition temperature of the cell wall .
  • the osmotic solution is substantially free of preservatives such as sulfites and phosphates.
  • the osmotic solution comprises low molecular weight carbohydrates.
  • Low molecular weight carbohydrates may include low molecular weight sugar.
  • Low molecular weight sugar may include monosaccharides such as glucose (dextrose) , fructose (levulose) , galactose, xylose and ribose and disaccharides such as sucrose, or combinations thereof.
  • low molecular weight sugar comprises honey.
  • the honey solution may have a solid content of from 20 to 60 degree Brix.
  • Honey is naturally occurring in that it is not highly refined and has been used as a sweetener for beverages, confectionaries, desserts, baking products and also as a coating material for cereals or nuts.
  • the sugars present in honey are mainly disaccharides and monosaccharides: fructose
  • honey solution due to the presence of the above-mentioned low molecular weight carbohydrates, still has a high osmotic pressure which thereby permits ready water diffusion from the plant material into the osmotic solution.
  • honey provides a better plasticizing effect such that the processed plant material has a non-brittle texture, and also better rehydration properties.
  • a single sugar such as sucrose
  • the sugar tends to crystallize upon drying. This among other factors, results in a processed plant material having a hard and brittle texture.
  • honey as an osmotic solute also provides an aromatic honey flavor while maintaining the natural flavor of the plant material, without compromising the sensory properties of the plant material.
  • the pH value of the solution containing the osmotic agent ranges from about 3 to about 5, preferably from about 3.2 to about 4.5.
  • an aqueous honey solution having a pH value of the above preferred ranges helps to increase the firmness of the plant material, as the hydrogen-bonds in pectin gel is stronger at lower pK.
  • the osmotic dehydration process is carried out at ambient pressure under controlled temperature of 20 to 60 degree C, preferably 40 to 50 degree C. It is to be noted that high temperatures increase the rate of diffusion of water from the plant material into the osmotic solution and solute from the osmotic solution into the plant material.
  • the volumetric ratio of the osmotic solution to the plant material ranges from about 2:1 to about 20:1, preferably from about 5:1 to about 20:1, or preferably from about 10:1 to about 20:1.
  • a high osmotic solution to plant material ratio reduces the level of dilution due to the water flowing out from the plant material into the solution, thereby maintaining the osmotic pressure difference between the osmotic solution and the plant material, and the. efficiency of mass transfer.
  • a low osmotic solution to plant material ratio requires relatively small amounts of solution which lowers equipment requirements and handling during the processing.
  • agitation is applied to prevent regional dilution of the osmotic solution and to create a downward force to keep the plant material immersed in the osmotic solution.
  • the plant material may be separated from the agitation device by containing them in a porous container such as a basket or a mesh screen.
  • the duration of the osmotic dehydration process ranges from about 30 minutes to 4 hours, to achieve a processed plant material with a water content of from about 50% to about 70%. The duration of the osmotic dehydration process may be dependent on the size and geometry of the plant material.
  • the plant material is cut into thin slices of thickness less than about 10 mm, or diced to dimensions of from about 3 to about 10 mm.
  • the plant material may be a vegetable or a fruit.
  • the plant material is a rooi vegetable selected from the group consisting of carrot, radish, sweet potato, turnip, potato, yam, onion and garlic.
  • the plant material is a fruit selected from the group consisting of cucurbits such as squash, pumpkin, and cucumber, tomato, eggplant, sweet pepper, spices such as allspice and chilli.
  • Carrot is known for its high contents of carotene and carotenoids besides appreciable amounts of vitamins Bl, B2, B3 and B ⁇ . It also contains a considerable amount of fibers (approx. 3%) and various minerals (potassium, phosphorus, calcium, etc) .
  • carrot's crispy texture and characteristic color and flavor are preferred in the food industry to produce varieties of products. Its ability to be sliced, diced, shredded or otherwise reduced in size without any adverse effect on the texture is especially preferred in many food processing steps.
  • FIG. 1 shows the weight and volume ratios of the carrot products that were obtained in accordance with one embodiment disclosed herein to the unprocessed raw carrots, before and after rehydration.
  • Fresh carrots were stored at 4 degree C. Upon processing, the carrots were taken out from the fridge, washed and cut into pieces of dimensions approximately 6x6x3 mm.
  • the superheated steam was generated by an autoclave machine (HiclaveTM HV-50, Hirayama) ; the temperature of the steam was 110 degrees C and the heating process lasts for 3 minutes.
  • Osmotic dehydration Carrot pieces were placed in a mesh screen and immersed into a honey solution of 30 ⁇ 0.5 degree Brix. The temperature of the solution was maintained at 50 ⁇ 0.5 degree C using a water bath. The osmotic solution was constantly stirred with a magnetic stirrer. The ratio of solution to carrot was kept at 20:1 (v/v) in order to avoid dilution.
  • Moisture content of product was determined by the oven drying method (AOAC, 1995) .
  • Product was weighed and placed in an oven set at 105 degree C and weighed again after 24 hours until constant weight was reached. Moisture content of the product was calculated from the weight readings before and after drying.
  • Water activity was measured by a water activity meter (Aqua lab Series 3) .
  • the solid content was expressed as grams of honey per gram of product. About 0.3 g of product was weighed and heated up in 30 ml deionized water for 30 minutes at 45 degree C. The mixture was homogenized and centrifuged at 5000 rpm and 40 degree C for 15 minutes. An aliquot of 0.3 ml of supernatant was pipetted and the Brix reading was measured using a refractometer (AGATO RX-5000a, Japan) . A standard curve of honey concentration vs. Brix reading was produced and the amount the honey present was calculated based on its Brix reading through the equation obtained from the standard curve.
  • Color of dehydrated product was measured by a spectrophotometer (Minolta CM-3500D) . Color profile was represented on the CI ⁇ L* (lightness/darkness) a* (redness/greenness) b* (y ⁇ llowness/blueness) (CIELAB) color scales.
  • the hardness of product was measured by a texture analyzer
  • Microbial analyses were carried out aseptically in a biohazard BSL2 cabinet. Each time 1 g of product was soaked in 9 ml sterile diluent solution (0.01% w/v tryptone, 0.85% w/v NaCl) for approximately 10 minutes. Serial dilutions from 10 ⁇ x to 10 ⁇ 4 levels were prepared using the same diluent.
  • Aerobic mesophilic Plate count agar 37 degree C for bacteria 48 hours
  • Rehydration tests Rehydration was performed by immersing a weighed amount of dehydrated product into hot water at controlled temperature of about 65 degree C for 8 minutes. The rehydration ratio, defined as weight of rehydrated product to weight of the dried product, was recorded. The weight and volume of product after rehydration was compared to the raw unprocessed carrot. The volume of product was calculated by dividing weight by density. The density of the product was measured by a programmed weighing machine (Shimudzu AUW220D, Japan) with its auxiliary density kit.
  • Carrots were washed, cut, pur into a mesh screen and immersed into 30 degree Brix honey solution where the osmotic dehydration was performed for 3 hours.
  • the carrot pieces were then separated from the solution, washed with clean water, drained and placed into the autoclave machine for the superheated steam treatment.
  • the superheated steam was programmed to be at 110 degree C for 3 minutes. After the steam treatment, the carrot pieces were placed on the metal plate inside a hot-air dryer and dried at about 37 degree C. for about 20 hours.
  • the resulting carrot product nad moisture content of about 20% and water activity of about 0.356.
  • the dehydrated product was slightly brownish in color, had a slightly rubbery texture and obvious shrinkage.
  • the carrots could be fully rehydrated at about 60 to 70 degree C within 5 minutes and the rehydrated carrots had a tender texture and sweet honey flavor. The color was similar to fresh carrots.
  • Example 2
  • Carrots were processed according to the same methods and conditions as described in Example 1, except the superheated steam treatment was performed prior to the osmotic dehydration process .
  • the resulting carrot product had moisture content of about 16% and water activity of about 0.346. Compared to carrots prepared in Example 1, the dehydrated product had more attractive bright orange color, a slightly softer texture, and less shrinkage was observed. The carrots could be fully rehydrated at about 60 to 70 degree C. within 5 minutes and the rehydrated carrots also had the honey flavor and were softer in texture. The color was similar to fresh carrots.
  • Comparisons were prepared by the same process procedures as described in Examples 1 and 2 with the replacement of honey solution by 40 degree Brix sucrose solution as the osmotic solution.
  • Control was prepared using the steps of steam treatment and hot-drying only; no osmotic dehydration process was applied.
  • TABLE 2 below shows the comparison in the measurement results of these differently prepared carrot products .
  • OD osmotic dehydration at 50 degrees C. for 3 liouis
  • TP thermal process with supei heated steam of 1 10 degrees C. for 3 minutes
  • HD hot-air drying at 37.5 degrees C. for 20 hours
  • iehydiation ratio weight after rehydration/ weight of dehydrated product.
  • sucrose treated product had relatively low moisture content, but higher water activity; while honey treated product was the opposite. This suggests that water was more tightly bonded into the carrot structure in the honey processed product, which indicates potentially more stable product. Color wise, from the L*, a*, b* values, sucrose treated product was brighter and redder; while honey treatment made the carrot darker and less yellowish. Texture analysis on the hardness of rehydrated carrot products showed that osmotic dehydration increased the hardness of the products and honey treatment has even greater effect than sucrose treatment. It is to be noted that the color and texture distribution is not uniform inside a single carrot stick, and there are more variations among different batches or types of carrots.
  • Weight ratio denotes the weight of processed carrot/weight of raw carrot
  • volume ratio volume of processed carrot/volume of raw carrot.
  • TP denotes thermal processed with superheated steam of 110 degrees C for 3 minutes
  • OD denotes osmotic dehydration with 30 degree Brix honey solution for 3 hours
  • a high quality processed plant material can be obtained using a combination of thermal and non-thermal processing methods.
  • the plant material is dried to obtain a dehydrated plant material, the dehydrated plant material has improved rehydration properties, without compromising the appearance and sensory properties.
  • the combination of immersing the plant material inro the osmotic solution, contacting the plant material with steam and further removing water from said plant material to substantially dehydrate said plant material leads to a processed plant material that is not too hard. It will be appreciated that the disclosed process prevents undesired color change and structure collapse of the plant material. Further, the disclosed process also helps in the reduction of volume and weight loss associated with the removal of the water from the plant material.
  • the osmotic solution is an aqueous honey solution. Therefore, the resulting processed plant material has better flavor, colour and additional nutritional values.
  • the processed plant material obtained therefrom has extremely low microbial count. Therefore, it is suitable for consumption by immune-compromised individuals, including infants, and the elderly.
  • the processed plant material are non-brittle, and maintain good appearance and sensory properties.
  • the rehydration of the processed plant material can be completed within minutes by addition of hot water and the rehydrated plant material has appropriate hardness and maintains the original natural plant material flavor.
  • the processed plant material is suitable for instant consumer-prepared products which need to be prepared by addition of hot aqueous solution or aqueous liquid, such as water, or heated mildly before eating (e. g. cereals, soup mixes, and frozen desserts) .
  • hot aqueous solution or aqueous liquid such as water
  • heated mildly before eating e. g. cereals, soup mixes, and frozen desserts

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Abstract

There is disclosed a process for treating a plant material comprising immersing the plant material in an osmotic solution containing an osmotic agent under conditions to at least partly infuse said osmotic agent into said plant material and release water contained therein; contacting the plant material with pressurized steam under conditions to substantially inactivate microbes in said plant material; and after said immersing and contacting steps, removing free water from said plant material. The immersing step may be undertaken after the contacting step or vice versa.

Description

Process for Treating Plant Material
Technical Field
The present invention generally relates to a process for preserving a plant material.
Background
Dehydrated fruit or vegetable products have become popular in the food industry due to their shelf stability and flexibility to be consumed alone as a snack, packed in conjunction with nuts or to be incorporated into varieties of other food products such as cereals, baking products, and so on. Depending on the purpose of usage, different drying techniques are used to produce products with specific characteristics. Osmotic dehydration is one of the most popular processing methods used to produce intermediate dried fruit and vegetable products or as a pre-dehydration step to produce dried products with a moisture content lower than 20% by weight. Osmotic dehydration is a process used to partially remove water from food items by placing solid food, whole or in pieces, in a concentrated sugar or salt solution of high osmotic pressure. The complex cell wall structure of food acts as a semi-permeable membrane where two simultaneous counter-current mass transfers take place. Specifically, (1) water flows out of the food and into the solution and (2) solute transfers from the solution into the food. At the same time, leaching of product solutes (such as sugars, acids, minerals and vitamins) into the osmotic solution also occurs. Such leaching may affect the organoleptic and nutritional cnaracteristics of product, but the amount of leaching is considered quantitatively negligible. Osmotic dehydration is also referred to as solid infusion since the solid (i.e. solutes) in the osmotic solution is transferred and infused into the food matrix during the process. Osmotic dehydration has received considerable attention as a pre-treatment in varieties of dehydrated food products, especially fruits and vegetables. Using osmotic dehydration as a pre- dehydration step has several advantages such as:
(i) reducing cost of operation by effectively removing a percentage of the water from the food product prior to drying processes, such as air drying, microwave drying, freeze drying etc.; (ii) increasing yield, as solid infused into the food product to thereby add low-cost bulk into it; (ϋi) reducing water activity of the product and increasing the microbiological stability; (iv) inhibiting undesired reactions, such as enzymatic and non-enzymatic browning; and (v) improving product quality in terms of nutritional content, rehydration properties, flavor, texture and color.
Although using a sugar as an osmotic agent helps to prevent collapse and shrinkage of the fruit or vegetable pieces, it often results in the agglomeration of the food product which leads to certain potentially undesirable characteristics being imparted to the fruit or vegetable pieces, such as hardening. For example, depending on the osmotic agent used, osmotic dehydration may lead to an increase in the hardness of the fruit or vegetable pieces which may make them difficult to consume and may detract from their naturally occurring hardness.
Furthermore, although the fruit and vegetable products prepared by the conventional osmotic dehydration methods have improved mechanical properties and shelf- stability, such products typically have less than desirable sensory properties. For example when conventional osmotic dehydration is carried out with sugar followed by further drying, the final products obtain may have a "candy-like" appearance and/or undesirable taste profile (i.e. too sweet or salty) . Furthermore, when further drying is applied, the dried products tend to have poor rehydration characteristics.
The most frequently used osmotic agents are sodium chloride, sucrose, glycerol, cane molasses, corn syrup or combinations of these compounds. However, since the commonly used osmotic agents are either not naturally occurring substances or are highly refined, the products obtained therefrom can nor be considered or marketed as natural and healthy products. Therefore, it is not suitable for certain food products, such as infant foods, that must fulfill special quality requirements.
Furthermore, the conventional methods used for preparing dehydrated fruit or vegetable products do not have strict controls on the microbiological stability of the processed products, which is one of the most important factor to consider when the intended consumers are immune- compromised consumers, such as infants, elders or diseased people . Therefore, there is a need to provide a process for preparing dehydrated fruit or vegetable products that overcomes, or at least ameliorates, one or more of the disadvantages described above. In particular, there is a need to provide a process for preparing dehydrated fruit or vegetable products that are not overly hard.
Summary
According to a first aspect, there is provided a process for treating a plant material comprising: immersing the plant material in an osmotic solution containing an osmotic agent under conditions to at least partly infuse said osmotic agent into said plant material and release water contained therein; contacting the plant material with pressurized steam under conditions to substantially inactivate microbes in said plant material; and after said immersing and contacting steps, removing free water from said plant material. In one embodiment, the step of removing free water comprises drying the plant material. The immersing step may be conducted before or after the contacting step. Advantageously, the contacting step not only inactivates microbes from the plant material but also helps to soften the plant material tissue so that once the plant material is dried, it will not be too hard and can be easily rehydrated. Therefore, the plant material obtained from the process disclosed herein has an extremely low microbial count, attractive appearance, texture, hardness and good rehydration ability.
In one embodiment, the disclosed process furtner comprises the step of drying the plant material to remove water from said plant material.
In one embodiment, the osmotic agent comprises low molecular weight carbohydrates. For example, the osmotic agent may be honey. The sugars present in honey are mainly disaccharides and monosaccharides: fructose (about 38.5%), glucose (about 31.0%) and small amounts of maltose, sucrose and other carbohydrates. Advantageously, due to the presence of these low molecular weight carbohydrates in the honey solution, the honey solution has a higher osmotic pressure and permits ready water diffusion from the plant material to the solution. Compared to using single sugar solute (most commonly, sucrose) solution, honey treatment has a better plasticizing effect that provides the product a non-brittle texture, and later better rehydration property.
According to a second aspect, there is provided a process for treating a root vegetable comprising the step of immersing the root vegetable in an osmotic solution containing an osmotic agent under conditions to at least partly infuse said osmotic agent into said root vegetable and release water contained therein. The osmotic agent may be honey and the root vegetable may be a carrot. According to a third aspect, there is provided a root vegetable or pumpkin at least partly infused with honey. The root vegetable or pumpkin may have at least one of the following characteristics: i) is substantially free of active microbes; ii) has a moisture content of less than 20% by weight; and iii) has a crunchy texture.
In one embodiment, the root vegetable is a carrot. In one embodiment, there is provided a processed plant material that is obtained from the process according to the first aspect. Advantageously, the processed plant material is capable of adsorbing an aqueous solution or aqueous liquid, such as water, to become substantially rehydrated. According to a fourth aspect, there is provided a method of rehydrating a plant material comprising immersing in aqueous solution or aqueous liquid, a processed plant material made in the process according to the first aspect. The aqueous solution or aqueous liquid may be water.
Advantageously, the rehydrated plant material has good nutritional and sensory qualities, particularly if a natural osmotic agent such as honey is used. According to a fifth aspect, there is provided a food package comprising a processed plant material made in the process according to the first aspect. The food package may include instructions for rehydrating said plant material.
According to a sixth aspect, there is provided a pediatric food, such as an infant cereal product, comprising a root vegetable or pumpkin at least partly infused with honey. The root vegetable or pumpkin may have at least one of the following characteristics: i) is substantially free of active microbes; ii) has a moisture contenr of less than 20% by weight; and iii) has a crunchy texture.
Definitions
The following words and terms used herein shall have the meaning indicated:
The term "plant material" is to be interpreted broadly to include any vegetable or fruit. Exemplary vegetable includes root vegetables such as carrot, radish, sweet potato, turnip, potato and yam. Exemplary fruit includes cucurbits such as squash, pumpkin, and cucumber, tomato, eggplant, sweet pepper, spices such as allspice and chilli.
The term "osmotic solution" is to be interpreted broadly to include any solution containing an osmotic agent having an osmotic pressure that is not the same as that across a semi-permeable membrane so that osmosis can occur across the semi-permeable membrane. The osmotic agent disclosed herein may comprise low molecular weight carbohydrates. The osmotic agent disclosed herein may also comprise salt. The term "low molecular weight carbohydrates" is to be interpreted broadly to include any edible carbohydrate, such as saccharide or sugar, having a molecular weight in the range of 60 to 20,000 g/mol. Exemplary low molecular weight carbohydrates include monosaccharides such as glucose (dextrose) , fructose (levulose) , galactose, xylose and ribose and disaccharides such as sucrose, and combinations thereof, such as honey.
The term "free water" in the context of this specification is used herein to indicate water that is nor chemically bound to the plant material.
The terms "inactivated microbes" or "inactive microbes" in the context of this specification is used herein to describe killed microbes, attenuated microbes, microbes that are not capable of growing, proliferating or microbes that have lost any activity that may aberrantly cause food deterioration. When describing a population of microbes as being "inactivated" in the context of this specification, it does not mean that the whole population of microbes within the plant material are necessarily inactivated, although they may be, but means that at least 90% of the total microbe population will be inactivated. More typically, at least 95% of the total microbe population will be inactivated and yet more typically, at least 98% of the total microbe population will be inactivated. The population of microbes can be determined by measuring the colony forming unit (CFU) according to methods known to those in the art. For example, if the microbial initial load is 100,000 CFU and 2000 CFU are left active after contacting with steam, tnen 98% of the microbes are inactivated.
The term "active microbes" refers to microbes that are not inactive microbes as described above. The term "sterilization" in the context of this specification, refers to a plant material that is undergoing treatment such that any microbes contained on said plant material become inactivated microbes, after the treatment step, as defined above. Likewise, the term "sterilized" refers to a plant material has undergone sterilization as defined above.
The term "crunchy texture" refers to a plant material that when chewed by a person, exhibits a crisp and crunching sensation for the first of several chews.
The term "microbes" in the context of this specification may refer to fungi, bacteria, viruses and bacterial spores.
The word "substantially" does nor exclude "completely" e.g. a composition which is "substantially free" from Y may be completely free from Y. Where necessary, the word "substantially" may be omitted from the definition of the invention.
Unless specified otherwise, the terms "comprising" and "comprise", and grammatical variants thereof, are intended to represent "open" or "inclusive" language such that they include recited elements but also permit inclusion of additional, unrecited elements.
As used herein, the term "about", in the context of concentrations of components of the formulations, typically means +/- 10% of the stated value, more typically +/- 4% of the stated value, more typically ÷/-
3% of the stated value, more typically, +/- 2% of the stated value, even more typically +/- 1% of the stated value, and even more typically +/- 0.5% of the stated value .
Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.
Disclosure of Optional Embodiments Exemplary, non-limiting embodiments of a process for treating a vegetable or a fruit (such as by substantially removing liquid from the vegetable or fruit) will now be disclosed.
There is provided a process for substantially removing liquid from a plant material comprising non-thermal and thermal processes. The non-thermal process, i.e. "osmotic dehydration", relates to the step of immersing the plant material in an osmotic solution under conditions to substantially remove the liquid contained therein. The thermal process, i.e. "steam treatment", relates to the step of subjecting the plant material to steam to substantially inactivate microbes present in the plant material. The osmotic dehydration step can occur eitner before or after the steam treatment step. After said immersing and contacting steps, the process comprises removing free water from said plant material.
Advantageously, the steam treatment step not only acts as a sterilization step by effectively inactivating microbes from the plant material, it also allows for the softening of the tissues of the plant material. Advantageously, the processed plant material obtained therefrom has excellent sensory properties, is not too hard and can be easily rehydrated, even after an air- drying has been applied.
In a first embodiment, the steam treatment step occurs after the osmotic dehydration step. The steam used may be saturated in order to effectively transfer the amount of heat necessary to inactivate all types of microorganisms (i.e., using latent hear energy). The plant material may be contacted with superheated or saturated steam of temperature from 100 to 135 degrees C under high pressure. The plant material may be contacted with superheated or saturated steam of temperature of 100 degrees C for a period of from about 2 minutes to about 10 minutes. The plant material may also be contacted with superneated or saturated steam of temperature of 135 degrees C for a period of less than about 3 minutes.
In one embodiment, to inactivate microbes when the superheated or saturated steam is at a temperature of 110 degrees C, the step of contacting the plant material with the steam is at least 2.5 minutes, preferably about 2.5 minutes to 3.5 minutes. In one embodiment, the contacting will occur for about 3 minutes at 110 degrees C. In one embodiment, to inactivate microbes when the superheated or saturated steam is at a temperature of 121 degrees C, the step of contacting the plant material with the steam is at least 10 seconds, preferably about 10 seconds to 20 seconds. In one embodiment, the contacting will occur for about 14.4 seconds at 121 degrees C.
In one embodiment, to inactivate microbes when the superheated or saturated steam is at a temperature of 135 degrees C, the step of contacting the plant material with the steam is at least 0.5 seconds, preferably about 0.5 seconds to 1 second. In one embodiment, the contacting will occur for about 0.6 seconds at 135 degrees C.
It will be appreciated that it is preferable to operate the sterilization step of the steam at higher temperatures, such as above 110 degrees Celsius. This is because the microbes within the plant material are inactivated within a very short time. For example, if the temperature of the steam is above 121 degrees Celsius, the microbes will take less than 20 seconds to be inactivated. This short time period (less than 20 seconds) means that the plant material will not be degraded or "cooked" by the heat being supplied thereto. Hence, directly contacting a relatively high temperature steam (above about 120 degrees Celsius) confers microbial inactivity on the plant material without compromising on the texture and nutritional value of the plant material. Accordingly, in one embodiment, the temperature of the steam in said contacting step is above 110 degrees Celsius, or above 115 degrees Celsius, or above 120 degrees Celsius, or above 130 degrees Celsius.
Advantageously, the contacting step results in a slightly softer plant material than what one would nave if no direct steam sterilization were performed. This is particularly useful as the plant material may be made harder after osmotic dehydration. Desirably, the direct steam sterilization makes the plant material softer iout does not "over soften", that is, the plant material retains its original texture and crunchiness and does not have a "cooked" type texture. The disclosed steaming process is different from known conventional blanching processes wnicn merely serve to deactivate the enzymes present. Advantageously, when the plant material is contacted with steam of the temperatures given above for the respective amounts of time, not only will the enzymes present in said plant material be inactivated, microbes such as Penicillium, Phytophthora , Alternaria , Botrytis , Aspergillus , Pseudomonasr Erwinia, Bacillus and Clostridium present in said plant material will also be inactivated. More advantageously, the inventors have surprisingly discovered that when the disclosed steaming process is carried out together with the disclosed osmotic dehydration and drying step, the final processed plant material achieved has superior rehydration properties, taste and texture.
As the microbes are inactivated by the step of contacting with steam, there is a very low active microbial count present in the plant material. This makes the plant material, being substantially free of active microbes, useful for pediatric food such as an infant cereal product. Moreover, because in one embodiment the step of contacting the plant material with high temperature steam, as described above, for a relatively short period of time, the plant material is substantially free of microbes but is not too soft in that it still has a crunchy or crisp texture. Hence, the plant material produced according to tne disclosed process is substantially free of active microbes and maintains a crunchy texture. In one embodiment, the plant material is carrot or pumpkin and the process results in a crunchy carrot or pumpkin that not only is substantially free of active microbes but also retains its nutritional integrity, color, and flavor due to the combination of the steps of immersing, contacting and removing free water steps as defined above. More particularly, the carrot or pumpkin that has been produced in this disclosed process may be stored for significant periods of time (such as months) without significant loss of the carrot or pumpkins' nutritional integrity, color, and flavor.
17 The overall effectiveness of the process may be determined by the combination of temperature and time, as well as the initial microorganism load on the vegetable or fruit. For example, the microorganisms associated with fresh vegetables, which are rich in carbohydrates (5% or more) and low in protein (1 to 2%), come from soil, water, and other environmental sources. The most common spoilage may then be caused by molds, such as Penicillium, Phytophthora , Alternaria , Botrytis and Aspergillus . The bacteria species may include Pseudomonas , Erwinia , Bacillus and Clostridium. Accordingly, it may be necessary to employ a treatment period of about 1 to 10 minutes in order to obtain the desired level of microbial inactivation. Prolonged treatment may result in undesired product qualities, such as over softening and breakage of tissue structure and discoloration.
In a second embodiment, the osmotic dehydration step occurs after the steam treatment step. After the steam treatment step, the vegetable or fruit pieces may become soft and easily breakable, thus special care needs to be taken in handling the vegetable or fruit pieces. However, the osmotic dehydration step that follows can help to strengthen the plant material tissue thereby resulting in a processed plant material having a stronger cell structure. Therefore, advantageously, the processed plant material is then more tolerant to the heating or drying process to follow.
Consequently, when all other operation conditions and parameters are kept constant, the processed plant material that is obtained in accordance with the first embodiment meaning has a firmer and harder texture compared to that obtained in accordance with the second embodiment. It has been observed that upon rehydration, the processed plant material that is obtained in accordance with the first embodiment is crunchier. On the other hand, upon rehydration, the processed plant material that is obtained in accordance with the second embodiment is softer, and the time required for rehydration to achieve similar softness is comparatively shorter. Therefore, depending on the purpose of usage of the processed vegetable or fruit product., the order of the osmotic dehydration process and steam sterilization process can be alternated.
For example, when preparing products requiring firmer texture quality such as morning cereals and soup mixes, it may be more advantageous to conduct the osmotic dehydration process prior to the steam sterilization process. On the other hand, when preparing products that are suitable for consumers lacking in chewing abilities, such as infant cereals or snacks, it may be advantageous to conduct the steam sterilization process prior to the osmotic dehydration process so that a slightly softer product is obtained.
Advantageously, the order of the osmotic dehydration step and the steam treatment step does not affect the microbial stability of product. More advantageously, the risk of recontamination during the osmotic dehydration step, wnen it is preformed after tne steam sterilization step (as in accordance with the second embodiment) , is low since the high concentration osmotic solution is itself microbiologically stable.
In one embodiment, after the osmotic denydration step, the plant material are separated from the osmotic solution, washed with clean water to remove any osmotic agent that may be remaining on the surface of the plant material and drained to dry.
The step of further removing water from said plant material to substantially dehydrate said plant material may be a drying step. This drying step typically occurs after the osmotic dehydration and steam treatment steps.
"i Δ Typically, the plant material has a moisture content of about 50 to 70% by weight after osmotic dehydration and at the beginning of the drying step.
The plant material may be spread over a pan or a belt contained within a convection oven and dried by directing a stream of hot air over the plant material.
The plant material may be dried at a temperature in the range of from about 30 to about 80 degrees C, preferably from about 35 to about 60 degree C. In one embodiment, the drying step is performed until a final moisture content of about 10 to 20% or a water activity of 0.30 to 0.50 is reached.
Advantageously, the drying step allows for a further reduction in the water activity and increase in the microbiological stability of the eventually obtained dehydrated plant material (which is dry and stable) .
Advantageously, the resulting dehydrated plant material has water activity comparable to those prepared by simple conventional drying techniques, while it does not have their compromised taste, color, textural or nutritional qualities. The osmotic solution may be any solution having an osmotic pressure that is not the same as that within the plant material so that osmosis can occur across the cell wall, which acts as a semi-permeable membrane, of the plant material.
The osmotic pressure in the osmotic solution is higher than that in the plant material. Accordingly, water diffuses from the plant material into the osmotic solution while the solute infuses into the plant material. The infused solute can strengthen the cell wall of the vegetable or fruit by interacting with the pectin substance in the middle lamella and filling up part of the void space created by the diffusion of water out of the plant material and changing the glass transition temperature of the cell wall .
In one embodiment, the osmotic solution is substantially free of preservatives such as sulfites and phosphates.
In one embodiment, the osmotic solution comprises low molecular weight carbohydrates. Low molecular weight carbohydrates may include low molecular weight sugar. Low molecular weight sugar may include monosaccharides such as glucose (dextrose) , fructose (levulose) , galactose, xylose and ribose and disaccharides such as sucrose, or combinations thereof.
In one embodiment, low molecular weight sugar comprises honey. The honey solution may have a solid content of from 20 to 60 degree Brix.
Honey is naturally occurring in that it is not highly refined and has been used as a sweetener for beverages, confectionaries, desserts, baking products and also as a coating material for cereals or nuts. The sugars present in honey are mainly disaccharides and monosaccharides: fructose
(about 38.5%), glucose (about 31.0%), small amount of maltose, sucrose and other carbohydrates. In comparison to single sugar solutions, the honey solution (due to the presence of the above-mentioned low molecular weight carbohydrates) still has a high osmotic pressure which thereby permits ready water diffusion from the plant material into the osmotic solution. More advantageously, in comparison to a single sugar, honey provides a better plasticizing effect such that the processed plant material has a non-brittle texture, and also better rehydration properties. When a single sugar (such as sucrose) is used, the sugar tends to crystallize upon drying. This among other factors, results in a processed plant material having a hard and brittle texture. Furthermore, it is difficult to rehydrate a non-amorphous processed plant material as it frequently results in a hard center due to the crystallized sugar and this is even more apparent if the vegetable or fruit is not thin and small. There are other components present in honey, including several vitamins (B group vitamins, vitamin C, thiamin, niacin, riboflavin and pantothenic acid) , essential minerals
(calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium and zinc) and several different amino acids. Advantageously, these nutrients are incorporated into the plant material during the osmotic dehydration process, thereby providing additional nutritional benefits. Advantageously, honey as an osmotic solute also provides an aromatic honey flavor while maintaining the natural flavor of the plant material, without compromising the sensory properties of the plant material.
In one embodiment, the pH value of the solution containing the osmotic agent ranges from about 3 to about 5, preferably from about 3.2 to about 4.5. Advantageously, an aqueous honey solution having a pH value of the above preferred ranges, helps to increase the firmness of the plant material, as the hydrogen-bonds in pectin gel is stronger at lower pK.
In one embodiment, the osmotic dehydration process is carried out at ambient pressure under controlled temperature of 20 to 60 degree C, preferably 40 to 50 degree C. It is to be noted that high temperatures increase the rate of diffusion of water from the plant material into the osmotic solution and solute from the osmotic solution into the plant material.
In one embodiment, the volumetric ratio of the osmotic solution to the plant material ranges from about 2:1 to about 20:1, preferably from about 5:1 to about 20:1, or preferably from about 10:1 to about 20:1. A high osmotic solution to plant material ratio reduces the level of dilution due to the water flowing out from the plant material into the solution, thereby maintaining the osmotic pressure difference between the osmotic solution and the plant material, and the. efficiency of mass transfer. On the other hand, a low osmotic solution to plant material ratio requires relatively small amounts of solution which lowers equipment requirements and handling during the processing. When a low osmotic solution to plant material ratio is employed, an appreciable dilution of osmotic solution may occur during the osmotic dehydration process. This results in a reduction in the rate of mass transfer in the system. Therefore, in one embodiment, evaporation of water from the osmotic solution, or addition of solute to the osmotic solution, is carried out.
In one embodiment, agitation is applied to prevent regional dilution of the osmotic solution and to create a downward force to keep the plant material immersed in the osmotic solution. In order to prevent mechanical damage, which may be caused by the agitation on the plant material tissue, the plant material may be separated from the agitation device by containing them in a porous container such as a basket or a mesh screen. In one embodiment, the duration of the osmotic dehydration process ranges from about 30 minutes to 4 hours, to achieve a processed plant material with a water content of from about 50% to about 70%. The duration of the osmotic dehydration process may be dependent on the size and geometry of the plant material.
In one embodiment, the plant material is cut into thin slices of thickness less than about 10 mm, or diced to dimensions of from about 3 to about 10 mm.
The plant material may be a vegetable or a fruit. In one embodiment, the plant material is a rooi vegetable selected from the group consisting of carrot, radish, sweet potato, turnip, potato, yam, onion and garlic. In another embodiment, the plant material is a fruit selected from the group consisting of cucurbits such as squash, pumpkin, and cucumber, tomato, eggplant, sweet pepper, spices such as allspice and chilli. Carrot is known for its high contents of carotene and carotenoids besides appreciable amounts of vitamins Bl, B2, B3 and Bβ. It also contains a considerable amount of fibers (approx. 3%) and various minerals (potassium, phosphorus, calcium, etc) . As a root vegetable, carrot's crispy texture and characteristic color and flavor are preferred in the food industry to produce varieties of products. Its ability to be sliced, diced, shredded or otherwise reduced in size without any adverse effect on the texture is especially preferred in many food processing steps.
Brief Description Of Drawings The accompanying drawings illustrate a disclosed embodiment and serves to explain the principles of the disclosed embodiment. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention.
FIG. 1 shows the weight and volume ratios of the carrot products that were obtained in accordance with one embodiment disclosed herein to the unprocessed raw carrots, before and after rehydration. Examples
Materials and methods used in the Examples Sample preparation
Fresh carrots were stored at 4 degree C. Upon processing, the carrots were taken out from the fridge, washed and cut into pieces of dimensions approximately 6x6x3 mm.
Heating with superheated steam
The superheated steam was generated by an autoclave machine (Hiclave™ HV-50, Hirayama) ; the temperature of the steam was 110 degrees C and the heating process lasts for 3 minutes.
Osmotic dehydration Carrot pieces were placed in a mesh screen and immersed into a honey solution of 30±0.5 degree Brix. The temperature of the solution was maintained at 50±0.5 degree C using a water bath. The osmotic solution was constantly stirred with a magnetic stirrer. The ratio of solution to carrot was kept at 20:1 (v/v) in order to avoid dilution.
Hot-air drying
Conventional hot-air drying was carried out in a hot-air dryer set. The air was heated at the inlet to above 100 degree C before entering the drying chamber. The chamber temperature was maintained at 37±1.0 degree C and the air flow rate was maintained at about 1.3±0.1 m/s.
Measurement of moisture content and water activity (A«)
Moisture content of product was determined by the oven drying method (AOAC, 1995) . Product was weighed and placed in an oven set at 105 degree C and weighed again after 24 hours until constant weight was reached. Moisture content of the product was calculated from the weight readings before and after drying.
Water activity was measured by a water activity meter (Aqua lab Series 3) .
Measurement: of solid content
The solid content was expressed as grams of honey per gram of product. About 0.3 g of product was weighed and heated up in 30 ml deionized water for 30 minutes at 45 degree C. The mixture was homogenized and centrifuged at 5000 rpm and 40 degree C for 15 minutes. An aliquot of 0.3 ml of supernatant was pipetted and the Brix reading was measured using a refractometer (AGATO RX-5000a, Japan) . A standard curve of honey concentration vs. Brix reading was produced and the amount the honey present was calculated based on its Brix reading through the equation obtained from the standard curve.
Measurement of color
Color of dehydrated product was measured by a spectrophotometer (Minolta CM-3500D) . Color profile was represented on the CIΞ L* (lightness/darkness) a* (redness/greenness) b* (yεllowness/blueness) (CIELAB) color scales.
Measurement of texture
The hardness of product was measured by a texture analyzer
(TA-TXT2i) using a cylindrical flat-probe (25 mm diameter; aluminum) . Hardness was defined as the compression force
(g) at 30% strain along the 3 mm dimension with a deformation rate of 0.2 mm/s. Microbial enumeration
Microbial analyses were carried out aseptically in a biohazard BSL2 cabinet. Each time 1 g of product was soaked in 9 ml sterile diluent solution (0.01% w/v tryptone, 0.85% w/v NaCl) for approximately 10 minutes. Serial dilutions from 10~x to 10~4 levels were prepared using the same diluent.
Pour plate method was used. Each time 1 ml of sample dilution was transferred into a sterile Petri dish and about 15 ml of agar solution (45 degree C) was poured. The inoculum and the medium were mixed immediately. After solidify, the plate was transferred into an incubator of 37 degree C. For the violet red bile glucose agar (VRBG) media, after the solidification of the first layer, a second layer was prepared by adding about 5 ml VRBG on the surface and allowing solidify. All the plates were duplicated. Incubation conditions are listed in TABLE 1 below.
TABLE 1. Inoculation media and conditions for microorganisms
Type of Media Incubation microorganism condition
Aerobic mesophilic Plate count agar 37 degree C for bacteria 48 hours
Enterobacteriaceace Violet red bile 37 degree C for glucose (VRBG) agar 48 hours
Rehydration tests Rehydration was performed by immersing a weighed amount of dehydrated product into hot water at controlled temperature of about 65 degree C for 8 minutes. The rehydration ratio, defined as weight of rehydrated product to weight of the dried product, was recorded. The weight and volume of product after rehydration was compared to the raw unprocessed carrot. The volume of product was calculated by dividing weight by density. The density of the product was measured by a programmed weighing machine (Shimudzu AUW220D, Japan) with its auxiliary density kit.
Sensory assessment
All products were informally assessed for organoleptic quality by five experienced assessors. The attributes assessed were appearance (color, shrinkage) , flavor and texture. Both dehydrated and rehydrated produces were assessed.
Example 1
Carrots were washed, cut, pur into a mesh screen and immersed into 30 degree Brix honey solution where the osmotic dehydration was performed for 3 hours. The carrot pieces were then separated from the solution, washed with clean water, drained and placed into the autoclave machine for the superheated steam treatment. The superheated steam was programmed to be at 110 degree C for 3 minutes. After the steam treatment, the carrot pieces were placed on the metal plate inside a hot-air dryer and dried at about 37 degree C. for about 20 hours.
The resulting carrot product nad moisture content of about 20% and water activity of about 0.356. The dehydrated product was slightly brownish in color, had a slightly rubbery texture and obvious shrinkage. The carrots could be fully rehydrated at about 60 to 70 degree C within 5 minutes and the rehydrated carrots had a tender texture and sweet honey flavor. The color was similar to fresh carrots. Example 2
Carrots were processed according to the same methods and conditions as described in Example 1, except the superheated steam treatment was performed prior to the osmotic dehydration process .
The resulting carrot product had moisture content of about 16% and water activity of about 0.346. Compared to carrots prepared in Example 1, the dehydrated product had more attractive bright orange color, a slightly softer texture, and less shrinkage was observed. The carrots could be fully rehydrated at about 60 to 70 degree C. within 5 minutes and the rehydrated carrots also had the honey flavor and were softer in texture. The color was similar to fresh carrots.
Comparative Examples
Comparisons were prepared by the same process procedures as described in Examples 1 and 2 with the replacement of honey solution by 40 degree Brix sucrose solution as the osmotic solution.
Control was prepared using the steps of steam treatment and hot-drying only; no osmotic dehydration process was applied. TABLE 2 below shows the comparison in the measurement results of these differently prepared carrot products .
TABLE 2. Properties ofdehydiated cairots prepared by different processes, a = 6.
(OD: osmotic dehydration at 50 degrees C. for 3 liouis; TP: thermal process with supei heated steam of 1 10 degrees C. for 3 minutes; HD: hot-air drying at 37.5 degrees C. for 20 hours; iehydiation ratio: weight after rehydration/ weight of dehydrated product.)
Sample preparation Control Osmotic solution: 40 degrees Biϊx sucrose Osmotic solution: 30 degrees Brix honey
(No osmotic process)
1 P ) HO OD + TP+ IiD TP + OD -i HD OD +TP+ HD TP+ OD+ HD
Moisluie content 0.1793 ± 0.007.1 0.1228 ± 0.0064 ' 0.0715 * 0.0080 0.1953 * 0.0077 0.1636 ± 0.001 1 (g/g sample)
VValer activity at 0.399 ± 0.003 0.417 * 0 003 0.603 ± 0.005 0.356 ± 0.043 ! 0.346* 0.039 24.5 ± 0.S degrees C.
Solid gain f N/Λ 0.207 * 0.066 0.353 ± 0 016 0.091 ± 0.013 0.132± 0.079 sucrose/lioney infused /g sample Color index L* 36.8020 + 2.6574 42.1649 ± 1.7642 40.4518 ± 0.7942 30.0900 * 1.8195 j 31.2635 ± 1.9613
16.4652 ± 3 9046 14.4806 * 2.0053 24.0414 * 1.9779 17.8798 ± 0*3183 I 15.0738* 1.1482
23.6808 * 1.0467 25.9216 . t 8.1687 3 ϊ .9809 ± 1.5527 19.7053 ± 0.9880 16.9092 * 0.5816
Texture Slightly dull color: Slightly dull color; less Blight orange color; less Slightly brownish and Bright orange color; least and Appearance severe shrinkage. shrinkage than control; shrinkage than OD first dull; slightly rubbery; shrinkage observed; slightly hard and slightly brittle. ; caπot; most brittle and surface slightly sticky. lubbεry; surface slightly hard. sticky.
Rehydration ratio 6.56 ± 0.27 3.19 * 0.03 2.38± 0.07 3.20 * 0.01 I 3.02 ± 0.16
Hardness ( g ) 188.155 * 0.519 247.013 ± 0.639 217.375 ± 0.629 347.603 ± 0.671 I 238.34 * 0.654
Sensoiy qualities Soft; taste plain; Soft; taste sweet; color | Soft; taste sweet; color Soft; taste sweet with j Soft; taste sweet with honey cairot flavor, pale similai to control. similar to control. honey flavor; color 1 flavor; color similar to i orange, slightly similar to control. ! control. yellowish.
Comparing the effect of different types of osmotic agent, sucrose treated product had relatively low moisture content, but higher water activity; while honey treated product was the opposite. This suggests that water was more tightly bonded into the carrot structure in the honey processed product, which indicates potentially more stable product. Color wise, from the L*, a*, b* values, sucrose treated product was brighter and redder; while honey treatment made the carrot darker and less yellowish. Texture analysis on the hardness of rehydrated carrot products showed that osmotic dehydration increased the hardness of the products and honey treatment has even greater effect than sucrose treatment. It is to be noted that the color and texture distribution is not uniform inside a single carrot stick, and there are more variations among different batches or types of carrots. Therefore, both the color profiles and the hardness values measured here only intend to show the general trends; the actual values are very dependent on the properties of the carrots used. Sensory assessment revealed that at their dehydrated forms, sucrose treated carrots were more brittle and hard; while noney treated carrots had a slightly ruboery texture. Upon rehydration, both treatments resulted in products with tender and soft texture; the honey treated carrots had apparent honey flavor.
Comparing the effect of different process sequences, when osmotic dehydration was performed after the steam treatment (i.e. as in Example 2), the resulted dehydrated carrots had lower final moisture content, greater amount of solid uptake. Color wise, these carrots were brighter and more attractive, which probably was due to the inactivation of polyphenoloxidase (PPO) through the heating. PPO is an enzyme present in many fruits and vegetables including carrot. It causes oxidation of natural phenolic compounds into quinones by chelation with copper and thus results in discoloration and browning. These carrots also had greater volume; after rehydration, they were softer. FIG. 1 shows the weight and volume ratios of the carrot products prepared according to the present invention to the unprocessed raw carrots both in their dehydrated forms and after rehydration. Weight ratio denotes the weight of processed carrot/weight of raw carrot; volume ratio: volume of processed carrot/volume of raw carrot. TP denotes thermal processed with superheated steam of 110 degrees C for 3 minutes; OD denotes osmotic dehydration with 30 degree Brix honey solution for 3 hours; HD denotes hot-air drying at 37.5 degree C for 20 hours, n=6. From the graph, osmotic dehydration with 30 degree Brix honey solution greatly increased product weight and volume compared to the control. When steam process was carried out before the osmotic dehydration (Example 2), the greatest volume ratio (almost 4 times of the control at the dehydrated form) and weight ratio (tripled the control) was obtained. After rehydration, the restored weight ratio of carrots prepared in accordance with Example 1 was almost 30% greater than the control and of carrots prepared in accordance with Example 2 was over 50% greater than tne control. Therefore, it is evident that the process according to the present invention can effectively increase product yield and thus benefits the producers.
The microbial counting showed that dehydrated carrot products prepared by both process procedures described in the examples above had total aerobic mesophilic bacteria count less than 100 cfu per gram of product, and enterobacteriaceace count negative per gram of product. Applications
It will be appreciated that a high quality processed plant material can be obtained using a combination of thermal and non-thermal processing methods. Advantageously, when the plant material is dried to obtain a dehydrated plant material, the dehydrated plant material has improved rehydration properties, without compromising the appearance and sensory properties.
It will be appreciated that the combination of immersing the plant material inro the osmotic solution, contacting the plant material with steam and further removing water from said plant material to substantially dehydrate said plant material, leads to a processed plant material that is not too hard. It will be appreciated that the disclosed process prevents undesired color change and structure collapse of the plant material. Further, the disclosed process also helps in the reduction of volume and weight loss associated with the removal of the water from the plant material. In one embodiment, the osmotic solution is an aqueous honey solution. Therefore, the resulting processed plant material has better flavor, colour and additional nutritional values.
Advantageously, the processed plant material obtained therefrom has extremely low microbial count. Therefore, it is suitable for consumption by immune-compromised individuals, including infants, and the elderly.
It will be appreciated that the processed plant material are non-brittle, and maintain good appearance and sensory properties.
It will also be appreciated that the rehydration of the processed plant material can be completed within minutes by addition of hot water and the rehydrated plant material has appropriate hardness and maintains the original natural plant material flavor.
It will be further appreciated that the processed plant material is suitable for instant consumer-prepared products which need to be prepared by addition of hot aqueous solution or aqueous liquid, such as water, or heated mildly before eating (e. g. cereals, soup mixes, and frozen desserts) .
It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention and it is intended that all such modifications and adaptations come within the scope of the appended claims.

Claims

Claims
1. A process for treating a plant material comprising: immersing the plant material in an osmotic solution containing an osmotic agent under conditions to at least partly infuse said osmotic agent into said planr material and release water contained therein; contacting the plant material with pressurized steam under conditions io substantially inactivate microbes in said plant material; and after said immersing and contacting steps, removing free water from said plant material.
2. The process as claimed in claim 1, wherein said removing free water step comprises drying the plant material .
3. The process according to claim 1 or claim 2, wherein said contacting step is undertaken after said immersing step.
4. The process according to claim 1 or claim 2, wherein said contacting step is undertaken before said immersing step .
5. The process according to any one of the preceding claims, wherein said osmotic agent comprises low molecular weight carbohydrate.
6. The process according to claim 5, wherein said low molecular weight carbohydrate comprises a low molecular weight sugar.
7. The process according to any one of claims 1 to 4, wherein said osmotic agent is honey.
8. The process according to claim 7, wherein said honey solution has a solid content of from 20 to 60 degree Brix.
9. The process according to any one of the preceding claims, wherein the ratio of said osmotic solution to said plant material is 2:1 to 20:1 by volume.
10. The process according to any one of the preceding claims, wherein after said immersing step, the moisture content of the plant material is 50 to 70% by weight.
11. The process according to any one of the preceding claims, wherein said osmotic solution has a pH value of 3 to 5.
12. The process according to any one of the preceding claims, wherein said immersing step is carried out at a temperature of 30 to 60 degree C.
13. The process according to any one of the preceding claims, wherein said immersing step is carried out in the range of 30 minutes to 4 hours.
14. The process according to any one of the preceding claims, wherein said contacting step is carried out at a temperature of 100 to 135 degree C.
15. The process according to any one of the preceding claims, wherein said contacting step is carried out for less than 3 minutes at a temperature of at least 110 degrees Celsius.
16. The process according to any one of claims 2 to 15, wherein said drying step is carried out at a temperature of 30 to 70 degree C.
17. The process according to any one of claims 2 to
16, wherein said drying step is undertaken until the plant material has a moisture content of 10 to 20% by weight .
18. The process according to any one of the preceding claims, wherein said plant material is a vegetable.
19. The process according to claim 18, wherein said vegetable is a root vegetable.
20. The process according to claim 19, wherein said root vegetable is carrot.
21. The process according to any one of claims 1 to
17, wherein said plant material is pumpkin.'
22. The process according to any one of the preceding claims further comprising, before said immersing step, the step of cutting the plant material.
23. The process according to claim 22, wherein said cutting step comprises cutting the plant material tc a thickness less than 10 mm.
3Z
24. A process for treating a root vegetable comprising the step of immersing the root vegetable in an osmotic solution containing an osmotic agent under conditions to at least partly infuse said osmotic agent into said root vegetable and release water contained therein.
25. A process as claimed in claim 24, wherein the osmotic agent is honey.
26. A process as claimed in claim 24 or claim 25, wherein the root vegetable is a carrot.
27. A root vegetable or pumpkin at least partly infused with honey.
28. A root vegetable or pumpkin as claimed in claim 27, wherein the root vegetable or pumpkin has at least one of the following characteristics: i) is substantially free of active microbes; ii) has a moisture content of less than 20% by weight; and iii) has a crunchy texture.
29. A root vegetable as claimed in claim 27 or claim 28, wherein said root vegetable is a carrot.
30. A method of rehydrating a plant material comprising immersing in aqueous solution or aqueous liquid, a processed plant material made in the process according to any one of claims 1 to 23.
31. A food package comprising a processed plant material made in the process according to any one of claims 1 to 23.
32. A food package as claimed in claim 31, wherein the packaging includes instructions for rehydrating said plant material.
33. A pediatric food comprising a root vegetable or pumpkin at least partly infused with honey.
34. A pediatric food as claimed in claim 33, wherein the root vegetable or pumpkin has at least one of the following characteristics: i) is substantially free of active microbes; ii) has a moisture content of less than 20% by weight; and iii) has a crunchy texture.
PCT/SG2009/000055 2008-02-19 2009-02-19 Process for treating plant material WO2009105039A1 (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012048713A2 (en) * 2010-05-14 2012-04-19 Hernandez Valerio Rosinis D Dehydration and preservation of foodstuffs (meat, fruit and vegetables)
CN103461466A (en) * 2013-09-10 2013-12-25 兴化市绿禾食品有限公司 Method for processing dehydrated cucumbers
JP2014207894A (en) * 2013-03-26 2014-11-06 博明 岩本 Method for manufacturing processed fruit, and processed fruit
EP2940414A1 (en) * 2014-04-29 2015-11-04 ESG Kräuter GmbH Method and device for drying plant products

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB496358A (en) * 1937-06-17 1938-11-29 Gerhard Madaus Process for the production of stable storable raw food
US2420517A (en) * 1943-05-07 1947-05-13 Atlas Powder Co Dehydration of foods by means of hydrophilic liquids
JPS56154965A (en) * 1980-05-01 1981-11-30 Kiyousai Nojo:Kk Handmade gralic containing no agricultural chemical preserved with honey
US4464204A (en) * 1982-11-29 1984-08-07 A. E. Staley Manufacturing Company Alkylidenation of fructose with perfluorinated acid catalysts
EP0212583B1 (en) * 1985-08-15 1991-12-04 Toshimitsu KAWAMURA Method of manufacturing dried food and plant products
US5368873A (en) * 1990-12-24 1994-11-29 Mccormick & Company, Inc. Process for preparing dehydrated vegetable products
US5645876A (en) * 1994-01-14 1997-07-08 Cpc International Inc. Dehydrated vegetables and method for their preparation
US6004590A (en) * 1995-07-18 1999-12-21 Bestfoods Process for producing dehydrated vegetables
US6132794A (en) * 1998-01-26 2000-10-17 Graceland Fruit Cooperative, Inc. Infusion-drying of carrots
US6245294B1 (en) * 1998-12-17 2001-06-12 The United States Of America As Represented By The Secretary Of Agriculture Method and apparatus for surface treatment of materials
WO2001082710A1 (en) * 2000-05-04 2001-11-08 Harmathy Ildiko Process for preparing agricultural crops, particularly vegetables and fruits and the products thus obtained

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB496358A (en) * 1937-06-17 1938-11-29 Gerhard Madaus Process for the production of stable storable raw food
US2420517A (en) * 1943-05-07 1947-05-13 Atlas Powder Co Dehydration of foods by means of hydrophilic liquids
JPS56154965A (en) * 1980-05-01 1981-11-30 Kiyousai Nojo:Kk Handmade gralic containing no agricultural chemical preserved with honey
US4464204A (en) * 1982-11-29 1984-08-07 A. E. Staley Manufacturing Company Alkylidenation of fructose with perfluorinated acid catalysts
EP0212583B1 (en) * 1985-08-15 1991-12-04 Toshimitsu KAWAMURA Method of manufacturing dried food and plant products
US5368873A (en) * 1990-12-24 1994-11-29 Mccormick & Company, Inc. Process for preparing dehydrated vegetable products
US5645876A (en) * 1994-01-14 1997-07-08 Cpc International Inc. Dehydrated vegetables and method for their preparation
US6004590A (en) * 1995-07-18 1999-12-21 Bestfoods Process for producing dehydrated vegetables
US6132794A (en) * 1998-01-26 2000-10-17 Graceland Fruit Cooperative, Inc. Infusion-drying of carrots
US6245294B1 (en) * 1998-12-17 2001-06-12 The United States Of America As Represented By The Secretary Of Agriculture Method and apparatus for surface treatment of materials
WO2001082710A1 (en) * 2000-05-04 2001-11-08 Harmathy Ildiko Process for preparing agricultural crops, particularly vegetables and fruits and the products thus obtained

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
AKTAS, T. ET AL.: "Effects of Pretreatments of Sliced Vegetables with Trehalose on Drying Characteristics and Quality of Dried Products", TRANS ICHEME, PART C, FOOD AND BIOPRODUCTS PROCESSING, vol. 85, no. C3, 2007, pages 178 - 183 *
PAARMAN, I, COOK WITH INAPAARMAN, 2001, pages 74 *
STANTON, R.: "Vegetables", ALLEN & UNWIN, 2000, pages 49 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012048713A2 (en) * 2010-05-14 2012-04-19 Hernandez Valerio Rosinis D Dehydration and preservation of foodstuffs (meat, fruit and vegetables)
WO2012048713A3 (en) * 2010-05-14 2013-01-17 Hernandez Valerio Rosinis D Method for the dehydration and preservation of foodstuffs
JP2014207894A (en) * 2013-03-26 2014-11-06 博明 岩本 Method for manufacturing processed fruit, and processed fruit
JP2016112022A (en) * 2013-03-26 2016-06-23 博明 岩本 Method for producing processed fruit
CN103461466A (en) * 2013-09-10 2013-12-25 兴化市绿禾食品有限公司 Method for processing dehydrated cucumbers
EP2940414A1 (en) * 2014-04-29 2015-11-04 ESG Kräuter GmbH Method and device for drying plant products
WO2015165585A1 (en) * 2014-04-29 2015-11-05 Stg Dreihundertachtzigste Vermögensverwaltungs- Und Beteiligungsgesellschaft Mbh Method and device for drying vegetable products

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