SI9720001A - Process for removing the fat from deep-fried food - Google Patents

Abstract

The invention relates to a process and apparatus for the removal of fat from deep-fried foods. The process is preferably carried out using absolute ethanol and is particularly suitable for so-called snack products, e.g. potato crisps.

Description

The present invention relates to a process for degreasing fried food products, especially thin food products such as potato chips or other types of fried snack products, such as torti11a-corn-chips, and products made using synthetic fats, such as Sorbestrir (S or Olestr ^?),

Particularly starter products that contain starch, such as potatoes, are great for frying in hot oil, tasting good - and when crisp in thin slices, crispy products are produced. The most famous and widespread product of its kind is potato chips.

Of course, by today's dietary criteria, a high-fat product is undesirable for many consumers. Therefore, efforts have been underway for many years to reduce the fat content of fried products. As part of this effort, new blossoming oils are evaluated and process parameters optimized. For many uses, the corresponding fat production is still too high.

The state of the art

One of the processes for degreasing fried products is known from DE-A-32 15 315. In accordance with the prior art, fried products are placed in a container, which is then filled with an organic solvent and then emptied again after a given waiting time.

2Extraction can be repeated. Organic solvents are referred to as boiling in the range of -5'C to 100 ° C. Ethanol and dichloromethane are mentioned as preferred solvents. The advantage of ethanol is the high ability to dissolve the oil at high temperatures, whereby the hot dissolved oil is re-extracted or precipitated when cooled to, for example, room temperature, allowing for easy recycling of ethanol.

This process according to the state of the art is preferably carried out with technical alcohol, i.e. with 96% ethanol, using 8001 ethanol per 100 kg of potato chips.

In other areas of the food industry, especially in the field of oil production, the processes of oil extraction are already known. An overview of these procedures is provided by L.A. Johnson and E.W. Lusas in Comparison of Alternative Solvents for Oil Extraction, JAOCS, Volume 60, no. 2 (February 1983) page 229241. This review article discusses the various solvents that can be used in the production of oil from oilseeds instead of the most widely used hexane. In addition to using conventional 96% ethanol, this document also addresses the possibility of using more concentrated 99% ethanol under pressure for oil production. According to laboratory experiments, the ability to dissolve oil with dehydrated ethanol is 1.9 times higher than that of 90% ethanol. From R.K. Rao et al. , Alcoholic Extraction of Vegetable Oils. V. Pilot Plant Extraction of Cottonseed by Aqueos Ethanol, The Journal of the American Oil Chemists' Society, Volume 35 (June 1958, pages 277-280), one of the articles cited above, makes it clear that, in dried scales, with less than 3% residual moisture, the scales remain in about the same amount of oil when used

395.4% ethanol or 99.9% ethanol under the same process conditions, which is why 95% ethanol is recommended.

Touch and zoom

It is an object of the invention to develop an extraction process for fried products, in which the material to be extracted retains the structure obtained by preliminary boiling and is preferably not mechanically damaged. The process should run at the lowest possible energy consumption, and at the same time a suitable device must be offered to carry out the process.

The goal is achieved by realizing a process where dehydrated alcohol is used, that is, absolute alcohol.

A short opie s ri sbe

A device suitable for carrying out the process of the invention is shown in the drawing.

The drawing shows a flowchart illustrating an embodiment of the process of the invention.

Find the stars and the zoom

As this is an extraction process for foodstuffs, the use of alcohols, especially ethanol, is preferred for this purpose.

In this process, the preferred solvent is absolute ethanol in drinking quality. It was surprisingly found that in fried products with a moisture content below 3 wt. %, preferably below 1 wt. %, use of absolute ethanol relative to 96% ethanol surprising advantages. Thus, the ability to dissolve oil in absolute alcohol with boiling point when used on fried products is approximately 15 times better than in normal 96% alcohol. Absolute ethanol offers additional benefits. Thus, for example, the drying time for products is shorter, since the product cannot absorb any additional water during extraction and thus is less burdensome, while having absolute ethanol compared to other solvents than, for example, hexane, which is usually devoid of water, the advantage of being an integral part of the food itself. It further retains the crisps using absolute ethanol crispiness and becomes neither brittle nor soft. Due to the surprisingly high ability to dissolve the oil even at the boiling point, the action under pressure is unnecessary, and since there is no risk of the product receiving water from the solvent, the length of time that the thin chips are in the solvent is also not critical.

Extraction can be carried out in principle with any extractor 1, for example by dipping or spraying. However, extraction in a counterflow or cross flow extractor is preferred. For example, extraction can be carried out in one step or in several steps: this one or more steps can be selected from extraction processes i) spraying, if necessary, preheated chips (preferably preheated to extraction temperature) with absolute alcohol or miscella (miscella is solvent solution) at elevated temperature (for absolute ethanol at approx. 50-77 ° C) or ii) inundation of the chips with 'absolute alcohol or miscella. Typically, extraction is carried out at temperatures below 25 ° C below the boiling point of the solvent and the boiling point of the solvent. Alcohol or misccella, hereinafter referred to as solvent, in liquid form by spray refers to chips with or without pressure, where the solvent dissolves the surface oil and drips away as miscela M1. In a multi-step extraction, it usually remains 10-20 wt. In the chips that have undergone rough oil removal after the first step. % of oil.

It is useful to provide for the flooding of the chips with solvent in at least one step, preferably in the last step. After at least one step, the rest of the oil content is normally distributed homogeneously over the chips. This is an important secondary effect of this overflow process: standardized oil content. After the flood, the thought, the M2 thought is released.

As mentioned above, these extraction steps can be performed in a single counter flow unit. A preferred countercurrent extractor is a so-called cross-flow extractor in which the solvent is sprayed.

In another preferred embodiment, the counterflow extractor 1 is a bowl extractor or a cross rotary extractor.

the residence time of the product in each extraction step is not critical.

In order to keep the cost of the process as low as possible and to minimize the environmental burden, the solvent is recycled to extraction. For the optimum solvent life, the boiling process must be guided so that the water content of the chip when it is extracted is at most 1%. This ensures that nothing or only a minimal amount of water passes from the chips to the solvent, the more the solvent is diluted with water, the worse its ability to dissolve the oil. Therefore, to obtain the desired degreasing, a larger amount of solvent is required at a given amount of chips. Thus, more solvents need to be heated to the extraction temperature or dehydrated or replaced with an absolute solvent, which increases the cost of the device and operating costs.

In one of the preferred embodiments of the present invention, the chips go immediately after the last extraction step into the basic seasoning unit 2. The chips may be sprayed with spices in powder form containing only temperature-sensitive components and / or precursors. At the drying temperature that follows, the precursors create an aroma after being baked, compensating for any loss of flavor due to the removal of the oil containing the aroma. In this step, the temperature used is not critical, but preferably approximately the same as the extraction temperature so that no additional heating is required for drying.

In another preferred embodiment, the fried chips are only subjected to seasoning after complete extraction and drying. The quality of the base spice 2 is crucial here: the particle size of the spice powder is between about 40 and 80pm, with a size of about 50pm being particularly preferred. After extraction and drying, the temperature should be used below 80 ° C when starting.

Surprisingly, it has thus been shown that basic low-fat or fat-free chips can be used to perform basic spice 2 in the form of a rare mixture, that is, with solvent-dispersed temperature-sensitive substances and / or precursors. This is done by sprinkling the rare mixture over the chips or dipping the chips into the rare mixture. Thus spices with a rare mixture give a very homogeneous distribution of spices. Such seasoning may be carried out with a rare mixture having an ambient temperature, thereby avoiding the warming of the rare mixture. However, this requires more intense heating of the chips during drying. Low-boiling dehydrated solvents such as non-polar solvents such as hexane, diethyl ether, petroleum ether and the like, dehydrated alcohols such as propanol, isopropanol, ethanol, esters, or mixtures of low-boiling dehydrated dispersants are suitable solvents or dispersants.

It is essential for the choice of dispersant that it is liquid at the temperature of use, for example at room temperature, and that the boiling point is preferably below 100 ° C with respect to the subsequent drying. In order to obtain the solvent back as readily as possible and recycle it back into the extraction, it is preferable to use the same solvent for the dispersing agent as for the extraction process. In the degreasing process under consideration, this is absolute ethanol, or in every way ethanol-rich thought.

Surprisingly homogeneous spicy chips is one of the great benefits of spicy seasoning with a rare blend. Homogeneity can be further enhanced if a rare mixture and a defatted product is maintained in motion.

Of course, basic seasoning 2 can also be a combination of normal basic seasoning and seasoning with a rare mixture.

After basic seasoning, the chips go into drying 3. Drying 3 can be ~ 8 ~ carried out in one or more steps. To reduce the risk of explosion, drying may be carried out in an inert gas or in a vacuum, preferably at least one first step, optionally the second step, being carried out at a greatly reduced oxygen content. On drying, work is preferably carried out at at least one step in vacuum or at temperatures above 100 ° C with or without rapid gas movement in order to remove the solvent residue to a legally and sensory acceptable residue. This residue is usually food-grade and, for example, in Switzerland for ethanol less than 0.5% by weight. %. Preferably, the drying is carried out in two or three steps. In the first step, for example, neither gas nor heat can be supplied, that is to say, the alcohol evaporates spontaneously and can easily be recovered. In the second step, the heat can be supplied, for example, by irradiation of the hot surfaces of the walls, but without gas, so that the further part of the solvent is removed and is easily retrieved. Since no hot gas is supplied in these two initial steps and the solvent vapors are not particularly heavily diluted, they can be fed to the solvent recovery unit. Alternatively, in the second or third step, final drying takes place. Here, warm air, preferably dried, or especially in the second step, is supplied with shielding gas, such as nitrogen. For another alternative, the first steps (when drying in three steps with two steps) are carried out with the supply of hot inert gas - if necessary with the use of additional heating. In the first two steps of the three-step alcohol removal process, alcohol may be recovered in amounts of up to 99% in the condensation and / or adsorption or absorption process. The exhaust air from step 3 usually contains so little solvent that it is generally not economical to recover it. In any way, such air can be used as combustion air. Protective gas can be used in a circular system. In order to reduce the risk of explosion, the entire device should preferably be operated under inert gas. The individual layout is governed by the type of gas. All drying is carried out protected from humid air in order to prevent condensation of water from recovering the solvent 13, thereby obtaining a solvent containing water and therefore not suitable for extraction.

After drying, the chips, if necessary, go into liquid seasoning 4. The chips are sprayed with liquid or dispersed flavors, which contain temperature-sensitive and liquid components. Liquid spices must contain neither water nor alcohol, but on the other hand, the spices are dissolved in oil and / or suspended and / or dispersed. The oil also acts as a diluent at the same time and is added until the ability to spray is reached.

It goes without saying that, depending on the product you want, basic seasoning or seasoning with liquid spices, especially seasoning with liquid spices, may be lacking.

It was mentioned above that solvent extraction is envisaged for solvent recycling. This recycling is carried out by subjecting the individual mistletoe, whether mixed or unmixed, to coarse separation 5. In coarse separation, the miscella is first sifted or filtered and then cooled, preferably to below 20 "C. Generally, the solvent should be cooled by about 50 ° C, preferably even by about 70 ° C, in order to obtain the best possible oil extraction. During this cooling, the thought breaks down spontaneously into two phases: heavy, oil-rich M _o , and light, oil-poor phase M | _. These two phases may, depending on their different specific gravities, be separated from each other by, for example, sedimentation or centrifugation. With oil, the poor phase M _L can directly return to the extraction as solvent.

if the fermentation is carried out with grease or with oils containing grease then separation instead of the oil-rich and oil-poor phase is preferably achieved by distillation.

The oil-rich phase is added to fine separation 6. Fine separation 6 is carried out, for example, by vacuum distillation. The purpose of the vacuum here is to prevent the oil from contacting oxygen, thus preserving the oil which remains in this way more suitable for storage 7 and for re-use during the boiling process 8. Also, distilled alcohol can be extensively recovered by cooling traps and it is then re-fed in extraction.

In order to avoid mechanical damage to the chips, this is preferably transported from one step to the next by a conveyor system gentle enough to prevent breakage. Such non-fracture conveyor systems are grooves, for example, if, in this conveyor system, dosing is to be carried out at the same time, then the conveyor system is preferably selected from the group consisting of belt conveyors, bowl conveyors, vibrating conveyors, drum conveyors strips or some combination of two or more of these.

In a production plant in which the boiling capacity and the extraction ability are not optimally coordinated with each other, it is preferable to transport the products from the bouquet 8 through a container 14 for intermediate storage, thereby equalizing production fluctuations by means of a metering and transport system 15, which does not damage the products until extraction 1.

if the extraction is carried out in a continuously operating extractor 1, for example in an extractor with counter current or cross current and the basic seasoning 2 is carried out in bundles and again dried in the given case continuously, then such dosing and transport systems (no shown in the drawing) that do not break the product.

It doesn't matter if the chips are straight or structured in this process. However, in order to minimize the susceptibility to fracture, it is more advantageous to cut it thicker than usual and / or to make a corrugated cut. The thickness of a slice for flat chips usually varies in size from 1.1mm to 1.5mm.

if the solvent reaches a level of dirt that is no longer recyclable, such as too high a water content or too much emulsified accompanying substances, then it can be brought to the repair shop, which comprises miscella distillation 9, purification 10 and optionally a solvent absolutization step 11 followed by the return of the solvent to the solvent stock 12.

Various devices are suitable for carrying out the process of the invention. For smaller quantities, the process can be completely carried out in a vacuum dryer of the blade type. An appropriate dryer is, for example, the IST ΙΝΟΧ Standard Vacuum Dryer, which is available from AT GLATT AG, Schonenwerd, Switzerland. It is described in the prospectus UM VACUUM TROCKNER Ausgabe April 95 above

--12 ™ of the said company, wherein the discharge port (referred to in the prospectus as (7) the discharge valve) must be enlarged to allow frictionless operation.

In addition, different inlets and outlets must be added to the solvent to supply and remove the extraction medium, special standardization solution, rare spice mix and the like. This device performs all the steps related to the product and following one after the other in a series, that is, one or more extractions, standardized, starting with a rare mixture, drying.

It goes without saying that conventional solvent repair, fumigation and storage devices and the like can be easily connected to this device.

In the following cases, the present invention will be explained in more detail.

Example 1 ϊ.βθ with t_oj3e k z. u.2or.abo maj_hne £ a L ot_acj_j_s_k e ^ a extracts)

First, potato slices about 1.4mm thick undergo a regular flowering process. Then, the fried potato slices, about 1.4mm thick, are stored in the silo. Using the dosing chute, the chips in tact (1.7-2.0kg portions) are fed into the first chamber of a rotary small extractor (Krupp, type 1/1000/450). The extractor consists of 12 chambers, one chamber for filling, 7 further extraction chambers, one forcing, one for venting, one for emptying, and one for separating (between filling and emptying). The chambers are filled in tact and flooded with, for example, dehydrated ethanol having 75 ^e C, with ethanol being fed in the opposite flow to the chips. The pre-emptying rear chamber is reserved for sparse seasoning and oil standardization, that is to say, filling the sparse chamber with the purest ethanol prior to sparging. The thought from this chamber is fed through the heat exchanger to the previous chamber. Each extraction chamber is equipped with a small heating loop that maintains the extraction temperature at 75 ° C. the extraction time takes about 60-90 minutes, depending on the oil or fat content at the start of the process, as well as the desired final oil or fat content. In the pre-emptying chamber, the chips are inundated with a dispersion mixture consisting of ethanol with 4% spices consisting of salts, flavor precursors and HVP (hydrolized vegetable protein). The miscella emanating from the first chamber has an oil or fat content of 10-20%. Cool it to 2 ^e C and separated into its constituent phases by physical methods, for example using a centrifuge. The alcohol phase contains 2-2.5 wt. % oil and can be reused for extra crustaceans.

In a closed system, the extracted chips pass through a vibrating chute into a tape dryer, where it creates a uniform layer with a maximum height of 15 cm. This is followed by drying in a nitrogen atmosphere heated to 140 ^e C. The gas velocity should be about 1.5 m / s. Drying takes about 15 minutes, corresponding to a residual alcohol content of up to 0.5 wt. %.

Alcohol can be recovered from nitrogen by condensation, yielding over 99% yield. The dried chips are fed through a tube to the spice drum. It is sprayed there with a rare blend consisting of 40% oil

14compounded liquid and heat-sensitive aromatic substances. The amount of flavoring substances contained is about 3 wt. % of the total weight of the potato slices.

The potato chips thus obtained are a crunchy snack with a maximum oil or fat content of only 3-6 wt. %.

Example 2 (Procedure using a bowl ego extractor)

First, sliced potato slices of 1.4mm thickness undergo normal blooming. The fried potato slices, about 1.4mm thick, are then stored in the silo. Using the dosing chute, the chips are filled through the tubes into the extractor basket (approximately 5-7 kg portions). The extractor consists of 6 tubs filled with dehydrated ethanol (99%) and about 30 baskets through the chain through the tubs. During the extraction, the baskets are closed with a lid. Baskets with chips go from tub 1 to tub 6. Miscella is fed in the opposite direction, that is, miscella from the last vat is fed to the penultimate, and so on, with the mistela flowing on the principle of top draining from tub to tub.

Tube 6 is fed the purest ethanol, which is heated to 75 ° C by an external heat exchanger and the temperature of the ethanol during the extraction should not fall below 70 ° C. therefore, two further pumps and a heat exchanger are needed for two tubs, the extraction time takes about 45-60 minutes, depending on the oil or fat content at the start of the process, as well as the desired final oil or fat content.

The bowl extractor is housed in a closed system, with the exception of the inlet and outlet pipes. The system is filled and saturated with nitrogen. The evaporated ethanol is recovered through the condenser and then fed into the tub 6. The miscella from tub 1 contains from 10-20 wt. % of the oil and cooled to 2 ° C. The component phases are separated by physical methods, such as centrifuge. The alcohol phase contains 2-2.5 wt. % oil and can be reused for extraction.

In a closed system, the extracted chips pass through a vibrating dosing chute into a tape dryer, where it creates a uniform layer with a maximum height of 15 cm.

This is followed by drying in a nitrogen atmosphere heated to 140 ^e C. The gas velocity should be about 1.5 m / s. Drying takes about 15 minutes, corresponding to a residual alcohol content of not more than 0.5 wt. %.

Alcohol can be recovered from nitrogen through condensation, yielding over 99% yield. The dried chips are fed through a tube to the spice drum. It is sprayed there with about 3% oil and then applied 6-9 wt. % fine spice mix (<80pm).

The potato chips thus obtained are a crunchy snack with a maximum oil or fat content of only 3-6 wt. %.

Preferred embodiments of the invention are described above, but it should be borne in mind that the invention is not limited to these embodiments and may also be implemented in another way, while still remaining within the scope of the claims that follow.

Claims (13)

PATENT APPLICATIONS A process for degreasing fried food products by extraction with an organic solvent and subsequent drying, characterized in that absolute ethanol and / or miscella with a base of absolute ethanol is used as the solvent for extraction. Method according to claim 1, characterized in that the extraction is carried out at a temperature in the range of 25 ° C below the boiling point of the solvent and up to the boiling point of the solvent. A method according to claim 1 or 2, characterized in that the extraction is carried out in one or more steps, at least one step comprising the overflow of the chips. Method according to one of Claims 1 to 3, characterized in that at least the last step is an overflow. Method according to one of Claims 1 to 4, characterized in that the extraction is carried out in an anti-flow extractor (1) or in a cross-flow extractor (1). A method according to claim 5, characterized in that the counterflow extractor (1) is a bowl extractor. Process according to Claims 1 to 6, characterized in that after extraction the solvent with cooling for at least 50 ^e C is separated from the oil brought with it. Process according to claim 7, characterized in that it is followed by cooling '17 by about 70 ° C. Method according to one of Claims 1 to 8, characterized in that the food product travels before drying to the base seasoning (2), where at least one spice dispersed in the dispersion medium is added, especially in absolute ethanol or with ethanol-rich miscella, and then the food product is then dried. Method according to one of Claims 1 to 8, characterized in that the food product, after extraction and drying, is fed to the basic seasoning (2), ensuring that the spice mixture has a particle size of about 40 to 80pm. Method according to claim 11, characterized in that the basic seasoning (2) has particles with a size of about 50pm. 12. A process characterized in that absolute ethanol containing less than 3% by weight is used for degreasing fried food products. % water, especially <1 wt. % water. 13. A method, characterized in that the vacuum dryer used is of the type of blade driers and is equipped with inlets and outlets for fats for extraction of fats from fried food products.