MXPA00000109A - Methods of obtaining selected pectin fractions, such fractions and their use - Google Patents

Abstract

A method of providing selected fractions of high-esterified pectin, each having different functionalities, by consecutive extraction of a vegetable material with acidic aqueous solutions to obtain successive fractions of high-esterified pectin with increasing setting time. The vegetable material is optionally prior to being extracted subjected to an acid pre-treatment by heating it in a homogeneous mixture of water and a water-miscible organic solvent. The pectin fractions obtainable by the method have improved properties when used in the preparation of food products such as preserves and acidified milk products. The pectin fractions are also useful as starting materials in a method of obtaining deesterified and optionally amidated pectin fractions having additionally improved functional characteristics.

Description

METHODS TO OBTAIN SELECTED PECTIN FRACTIONS, SUCH FRACTIONS AND THEIR USE FIELD OF THE INVENTION The present invention relates to a method for obtaining selected pectin fractions, comprising the consecutive acid extraction of a vegetable mineral containing pectin to obtain the successive fractions of highly esterified pectin with increase in the adjustment time, and to the use of the pectin fractions obtained by the method in the preparation of food products. Such pectin fractions are also used as starter materials for the preparation of deesterified pectin fractions having further improved functional characteristics.

BACKGROUND OF THE INVENTION Pectin is a heteropolysaccharide found in the form of a pectic substance of water-insoluble origin - protopectin - in the primary cell wall and in the middle lamella of green earthen plants. Pectin is the generic designation for compounds REF .: 32425 resulting from the restricted hydrolysis of protopectin.

The exact nature of protopectin is not fully understood. However, in general, it is recognized that protopectin is a complex structure in which pectin binds to other components of cell walls, such as cellulose and hemicellulose, through covalent bonds, hydrogen bonds and / or ionic interactions Pectin is a linear polymer composed of D-galactopyranosyl uronic acid units that are linked by means of a-1-idic glycosides that form large chains of polygalacturonic acid. Parts of the carboxyl groups of the uronic acid units are esterified with methanol. In plants the residual carboxyl groups are partially or completely neutralized with calcium and magnesium cations which are inherently contained in the tissues of the plant.

The heteropolysaccharide nature of the pectin derivatives is due to the fact that other sugars are incorporated into the pectin molecule. The most common sugars are L-rhamnose, introduced by bonds ct-1.2- in the galacturonan structure, and ß-D-xylose, linked as single unit side chains mainly to 0-3 of the galactopyranosyl uronic acid residues in the structure , and D-galactose and L-arabinose, which occur in long side chains, only bound to rhamnopyranosyl residues.

The main sources of commercial pectin products are citrus peel and apple bagasse in which protopectin represents 10-40% by weight of dry matter.

Pectin in the isolated and more or less purified form is obtained largely from plant material by treating the material with an acid or. base under appropriate conditions, whereby the protopectin is separated, followed by extraction of the water soluble pectin. In conventional industrial pectin production, the plant-initiating material containing pectin treated with acid or base is subjected to extraction with dilute acid, this step is followed by the separation of the material from the plant that pectin has been removed, p . ex. , by filtration or centrifugation to obtain a viscous extract containing up to 1% by weight of the soluble pectin. This extract could be further purified and processed. Finally, the pectin is precipitated, separated and dried to obtain a commercial pectin product that is at least partially purified.

The hydrolysis of methyl esters of polygalacturonic acid occurs at acid and alkaline pH values, but dominates at pH values above 7, in particular above 9. The methyl ester groups of polygalacturonic acid are also hydrolysed by pectin esterases of the origin of plants. Pectin esterases are present in plant materials such as citrus fruits. Contrary to chemical hydrolysis which attacks the methyl ester groups of polygalacturonic acid in a random fashion, the pectin esterases are attacking near a free carboxyl group and proceeding along the structure, thus creating a distribution as a block or non-random free carboxyl groups.

For the water-soluble pectin resulting from the hydrolysis of protopectin, average values of 100,000 to 200,000 have been measured for the molecular mass.

Over time, several methods of extracting pectic substances from vegetable matter have been described, such as i. to. citrus peel, apple bagasse or beet pulp. These known processes have the purpose of extracting substantially all the pectin content from the pectin-containing starter material.

Thus, as an example, US 2,008,999 describes a method for producing pectin, which comprises subjecting a pectin-containing material to an extraction at a pH of 0.7 to 2.2 with a solution of a strong inorganic acid at a temperature of 50 to 75. ° C until the pectin is a simple test is precipitated by the calcium ions at a pH of 3 to 7, filtering the extraction mixture and recovering the pectin from the filtrate that has been brought to a pH of 3-7.

US 2,273,521 describes a process comprising treating a pectin-containing material with a solution of a solvent in which the pectin is insoluble and an inorganic or organic acid at a temperature of about 70 ° C and separating the residue from the extraction containing the pectin soluble in water. The pectin is recovered from the residue by extraction with water and isolated in solid form from the extract.

Other processes for preparing the pectin extracted in bulk are described in US 2,586,407, EP 688,792-A, US 4,016,351 and US 2,020,572.

Thus, the prior art describes the methods for producing the isolated pectin, wherein a material containing pectin is subjected to exhaustive extraction, e.g. ex. a substantially complete extraction and the pectin is recovered as a whole, ie, the pectin is provided as pectin extracted in bulk. Depending on the processing conditions including pH, temperature and extraction time, it is possible, to some extent, to control such bulky extraction processes, so that pectins having different degrees of esterification are obtained.

However, the characteristics of such extracted pectin products can only be defined in a statistical manner due to the variability in polymerization, methoxylation and acetylation, neutral sugar content and distribution of substituents throughout the structure. It is reasonable to assume that pectin molecules are not identical in a pectin preparation extracted in bulk. In this way, the physical and chemical properties of a single molecule of pectin i are determined. to. by the most molecular of the molecule and the concentration and distribution of free and esterified carboxyl groups in the molecule as well as the concentration and distribution of other groups in the molecule. Thus, molecules of pectin that have the same molecular mass and the same is terification, could interact differently with another molecule, particle or ion.

The degree of esterification (GE) of pectic substances is of considerable significance for the additive effects of pectin-containing products in foods. Typically, products containing pectin have a GE that is in the range of 10-90%. In particular foods it could be advantageous to use pectin which has a high GE, that is, more than 50%.

The highly esterified bulk pectin which has been extracted under the selected conditions to obtain bulk extracted pectin preparations having specific functional properties, often exhibits an undesirable development, such as giving rise to an opacity in gels, improved viscosity which results in the pregelification, incomplete solubility and syneresis in dairy systems, such as yogurt.

This undesirable development observed with pectin extracted in bulk is attributed to the molecular variability and a varied interaction between calcium ions and separate pectin molecules that have affinity variations towards calcium ions and other charged particles, such as for example proteins. .

The pectin products extracted in bulk comprise molecules that represent a wide distribution of the degree of methoxylation and molecules of a non-random pattern, as well as pattern of random methoxylation. This affects the quality parameters important for the pectin, as well as the time of adjustment, the resistance to breakage in gels, the profile of the adjustment temperature and the solubility of the pectin in food processing applications.

An important objective of the present invention is, therefore, to provide a method for the preparation of separate fractions of highly esterified pectin having improved functional characteristics over pectin extracted in bulk.

However, it has surprisingly been found that such selected pectin fractions are also very suitable starting materials for the preparation of derived pectin fractions which have exceptionally good functional characteristics. In this way, by subjecting the highly esterified pectin fractions according to the invention to treatment with an acid and / or ammonia under deesterification conditions, the de-esterified and optionally amidated pectin fractions can be obtained, which are useful as additives in various food applications, such as for example fruit preparations and dairy products. It has been found that such de-esterified pectin fractions have improved functional characteristics compared to the highly esterified pectin initiator material and the pectin extracted in bulk similarly treated.

BRIEF DESCRIPTION OF THE INVENTION Therefore, the present invention provides in a first aspect a method for obtaining the selected pectin fractions having successively increased adjustment times, the method comprising subjecting a highly esterified pectin-containing starter material to a first treatment cycle comprising a step of extracting the starter material with an aqueous extraction medium at an acid pH under conditions where only part of the pectin content is extracted, separating the pectin extract from the treated starter material and recovering the pectin from the extract to obtain a first fraction of pectin, followed by at least one additional treatment cycle, whereby the treated starter material extracted in the preceding cycle is treated to obtain a second and optionally one or more additional pectin fractions, the pH of the extraction medium in each of the second and the additional cycles is lower than in the in-treatment cycle ediatamente precedent.

In additional aspects, the present invention relates to a selected pectin fraction obtained by the above method, the fraction has a degree of esterification that is at least 50% and an adjustment time that is in the range of 0 to 100 sec. at 200 sec, 201 to 300 sec or in excess of 300 sec, the adjustment time is determined by the method of Joseph and Bair (Food Technology, 1949, 18, 18-22) in terms of the time required to obtain the gelation of a standardized hot pectin-sugar-water solution at pH 2.1 to 2.5 when cooled to a constant temperature of 30 ° C and to the use of such highly esterified pectin fractions in the preparation of a food product.

In a further aspect, the invention relates to a method for stabilizing an acidified dairy product comprising adding to the dairy product an amount of a pectin fraction as defined above, the addition of the fraction results in an improvement of the dairy product, the improvement is selected from the group consisting of at least 10% reduction in viscosity, at least 10% smaller particles and at least 10% less sediment, compared to the addition of the same amount of a pectin product extracted to Bulk The method of the present invention for obtaining highly esterified pectin fractions, involves significant advantages over the extraction of bulk pectin from the prior art by providing the selected and separated fractions of the highly esterified pectin, having a narrow distribution in the degree of methoxylation and having particular functionalities. In this way, the fractions successively obtained by the process according to the invention have adjustment times successively increased A significant aspect of the present invention is that it provides the means to obtain fractions of the total pectin content of the initiator material each of which has specific functional characteristics p. ex. with respect to the gelation properties which include the adjustment time as defined herein. By selecting the appropriate extraction conditions in the individual process cycles, it is possible to obtain the pectin fractions specifically suited for a specific purpose. It is also evident that the individual pectin fractions can be combined to form the compound pectin products having, in relation to the individually prepared original fractions, intermediate functional characteristics.

In food applications, such as in the manufacture of preserves and dairy products, p. ex. marmalade, jellies, yoghurt for drinking and yoghurt with fruit, or fruit and vegetable juices, the highly esterified pectin fractions provided by the above method of the present invention are superior to pectin extracted in bulk as a result of improved functional specificity , that it is said that the concentration of pectin having a specific functionality is increased in the pectin fraction.

The above-described highly pectin fractions of the invention are, as mentioned above, useful as starting materials in a method for obtaining de-esterified pectin fractions having improved functional characteristics.

Thus, in other aspects, the invention relates to a method for obtaining a desesified pectin fraction, which comprises subjecting a selected pectin fraction obtained by the above method and having a high degree of esterification that is 50% or higher , to at least one deesterification treatment step comprising reacting the highly esterified pectin fraction with a deesterification agent to obtain a pectin fraction having a degree of esterification (GE) that is reduced by at least 5% in relation to the highly esterified pectin fraction and a degree of amidation (GA) which is in the range of 0-25, such as in the range of 5 to 25, and to a fraction of distected pectin obtained by this method, this fraction has a degree of esterification that is less than 50% a degree of amidation that is in the range of 0 to 25, including the range of 5 to 25, and to the use of such a deesterified pectin fraction in the preparation of a food product.

DETAILED DESCRIPTION OF THE INVENTION Thus, in a first aspect, the present invention provides a method for selectively fractionating pectin, comprising the consecutive extraction of a starter material containing pectin with aqueous media or solutions at an acidic pH which is preferably at most 4, such as a pH in the range of 1 to 4, p. ex. in the range of 1 to 3 to obtain the successive extracts of the highly esterified pectin containing soluble pectin from successively increased adjustment time and recover the pectin from the extracts.

In the present context, the term 'consecutive extraction' is used to indicate a series of repeated treatment cycles [stages] involving repeated steps of extractions of a pectin-containing material in which a plant material containing pectin Or an extraction residue containing pectin results from the preceding extraction after separation of the extract and optionally the washing liquids are subjected to extraction in a subsequent extraction step.

As used herein, the term "extraction residue" refers to the undissolved material that is retained after the liquid extract has been separated from the extraction mixture.

In the present context, the term 'highly esterified pectin' indicates the pectin having a GE that is at least 50%, eg at least 5%, the highly pectin being of interest could have a higher GE such as minus 60% or at least 70%.

In the present context, the term 'adjustment time' refers to the well-known standard method according to Joseph and Bair (Food Technology, 1949, 18, 18-22) to determine the time required to obtain the desired gelation of a solution hot pectin-sugar-water standardized pH 2.1-2.5 when cooled to a constant temperature of 30 ° C.

According to the present invention, the starting materials useful for consecutive extraction are pectin-containing materials derived from natural plant materials in a fresh and dry state. Such suitable natural materials include, peel, pulp and / or waste of citrus fruits such as lemon, orange, citron, tangerine, grapefruit, tangerine, bergamot and citron species and their fruit similar to grapefruit and varieties and hybrids of several of these . Suitable natural materials that can also be used in the present invention include apple bagasse, pear bagasse, beet pulp, potato peel and carrot fiber.

Particularly interesting starting materials include dry skin of citrus fruits, having a dry matter content of about 90% by weight or more, preferably in the form of pieces of at most 2 cm in length, which is obtained from the industry of the juice after the extraction of citrus juice and essential oils. These materials have a high content of pectic substances _in the form of protopectin insoluble in water. The citrus peel having a pectin content in the range of 30-35% by weight or more on a dry matter basis is particularly interesting.

The method according to the invention is carried out as a series of separate, batch process cycles, each cycle comprising a step of extracting the pectin-containing material to obtain an extract containing pectin and a pectin recovery step. of the extract.

According to the invention, the pectin-containing material as defined above is understood to include the solid extraction residue arising from a preceding extraction step.

Thus, according to the present invention the method comprises at least two extraction and recovery cycles of pectin, e.g. ex. at least three stages of extraction, each followed by a recovery step of the extracted pectin.

According to the invention, the extraction comprises heating an aqueous acid suspension of the pectin-containing material to be extracted at a temperature in the range of 40 to 100 ° C for a period of 1 to 20 hours. The extractions are preferably carried out at a temperature in the range of 60 ° C to 80 ° C for a period of 1 to 10 hours, such as for a period of 1 to 5 hours at a temperature in the range of 60 ° C. at 80 ° C.

The amount of extraction medium to be used in each extraction stage depends i. to. of the origin and condition of the material containing pectin to be extracted, and the pectin content extracted in the material.

According to the invention, the amount of pectin-containing material and the extraction medium is chosen in each extraction step, which is carried out while gently stirring the suspension of the pectin-containing material, so that the suspension has a dry matter content that is in the range of 1% to 5% by weight, e.g. ex. in the range of 2% to 4% by weight.

Using the aforementioned amounts of the extraction liquid, a suspension is obtained which is easy to stir and pectin extracts are obtained which are not too viscous.

The acidity of the suspension is adjusted to an acid pH value which is p. ex. at most 4, such as in the range of 1 to 4 including the range of 1 to 3, by the addition of an organic or an inorganic acid, or a base. The acids used include strong inorganic acids as exemplified by, but not limited to, hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid. The bases used include ammonia and alkali metal hydroxides such as sodium hydroxide or potassium hydroxide or alkali metal carbonates, such as sodium carbonate or potassium carbonate. It will be understood that mixtures of acids or mixtures of bases could also be used to adjust the pH of the suspension.

The extraction parameters are established to obtain the fractions containing highly esterified pectin having a narrow distribution in molecular weight and esterification and several other parameters that give more uniform fractions of pectin with more specific functionality. This can be done by adjusting the extraction temperature, the extraction period and / or the pH during extraction. However, variations in temperature and extraction time affect the quality of the pectin. Therefore, pH is a preferred parameter that is used to control the consecutive extraction In this way, taking advantage of the different solubility and chelation capacity of the pectin molecules with metal ions include calcium and / or magnesium ions inherently present in the pectin-containing material to be extracted, the extractions at pH values decreased results in a high selectivity of the consecutive extraction stages and successive fractions containing pectin of increased adjustment time are obtained.

In accordance with the present invention, each extraction step after the first step is carried out at a pH value which is lower than the pH value in the immediately preceding extraction step.

During their experimentation, the present inventors have found that the presence of metal ions, in particular calcium and / or aluminum ions, in the aqueous extraction liquid improves the selectivity of the fractionation significantly.

Therefore, in a preferred embodiment of the invention the aqueous extraction medium contains an added water-soluble metal salt such as calcium and / or aluminum salts including, as examples, calcium chloride, calcium nitrate, calcium acetate, chloride of aluminum and aluminum sulfate. These calcium and / or aluminum salts are suitably added in such an amount that the concentration of the metal ion in the extraction liquid is in the range of 1 to 100 mmol such as in the range of 10 mmol to 40 mmol per liter of the liquid. extraction. At each extraction stage, the concentration of the metal ion in the extraction liquid could be the same or it could be different.

After an appropriate extraction time, the extraction mixture is cooled and the liquid is separated from the solid extraction residue, e.g. ex. by filtration or drained. After filtering or draining, the extraction residue still contains a large quantity of extracted pectin containing aqueous phase. Optionally, the solid extraction residue is washed with water in the filter or the residue is resuspended in water and filtered again to remove as much as possible the aqueous phase containing pectin. After separation of the washing liquid from the solid extraction residue, the washing liquid is combined with the extract. If it still contains highly methoxylated pectin, the extraction residue is subjected to an additional extraction The extracted pectin could be recovered from the individual extracts by any convenient method.

In the case that a high production of pectin with less functional specificity is required, it may be convenient to combine the extracts from an extraction step and a subsequent step and recover the pectin from the extract in this combined manner.

The pectin can be precipitated from the extract by the addition of the extract, which has optionally been concentrated, for example by membrane filtration or by evaporation under reduced pressure, to a water-miscible organic solvent. The organic solvent used to precipitate the pectin could be any solvent that is miscible in water and in which the pectin is substantially insoluble.

The solvent could be a monohydric alcohol, for example methanol, ethanol, isopropanol, tert-butanol, sec-butanol, n-butanol, tert-amyl alcohol, neopentyl alcohol, sec-amyl alcohol or diethylcarbinol; a dihydric alcohol, for example ethylene glycol, propylene glycol or tetramethylene glycol; a ketone, for example acetone, methyl ethyl ketone, methyl iso-butyl ketone or methyl tert-butyl ketone; or a glycol ether, for example, diethylene glycol monomethylether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether or triethylene glycol dimethyl ether. Mixtures of two or more such solvents could be used in the precipitation of the pectin.

The precipitated pectin is separated from the liquid by any convenient method, such as, for example, by filtration, and the precipitate is pressed and washed on the filter to remove salts and soluble impurities. Finally, the pectin is dried and optionally crushed.

In a preferred embodiment, the pectin could also be recovered from the individual extracts by adjusting the pH of the extracts to a level in the range of 1 to 5 such as in the range of 2 to 2.5 by the addition of an acid, e.g. ex. hydrochloric acid, or a base, such as for example ammonia, followed by the addition of a strongly acidic cation exchange in the salt form to raise the pH to a level in the range of 2.5 to 3.5 and stir the mixture at room temperature during 4 to 8 hours. After having the liquid separated from the ion exchange resin, the pectin is recovered from the liquid by precipitation with an organic solvent miscible with water as described above.

According to the invention, the pectin-containing starter material could be a pectin-containing material which optionally, before being extracted, is subjected to a pretreatment.

Thus, in a used embodiment of the invention in starter material containing pectin for consecutive extraction is a natural material as defined above, which has been subjected to a pretreatment with an acid, whereby at least part of the protopectin contained in the material is converted to water-soluble pectic substances under the conditions wherein the water-soluble pectic substances that are formed remain in an undissolved state in aggregation with the constituents of the insoluble plant cell, such as cellulose and hemicellulose , and in this way at least part of the non-pectinate substances such as, for example, sugar proteins, coloring matter and salts are removed.

According to the invention, such pretreatment comprises heating a suspension of the pectin-containing material at a temperature of 60 ° C to 80 ° C in a substantially homogeneous solvent mixture comprising water and at least one solvent in which the pectin is substantially insoluble to which an acid is added to maintain a fixed pH of the suspension within the range of 1 to 3 during the treatment and, subsequently, to separate the pre-treated pectin-containing material. The separated pre-treated material is subjected to at least one washing treatment and finally dried and, if desired, crushed to particles of a length of at most 2 cm.

An appropriate amount of the dry matter of the pectin-containing material in the pretreatment suspension is in the range of 5% to 15% by weight, preferably 5 to 10% by weight.

The solvent used in the pretreatment and / or in any washing treatment of the pre-treated material subsequent to the pre-treatment, could be any solvent in which the pectin is substantially insoluble because the pre-treatment implies that the pectin remains without dissolve during pretreatment. In addition, the solvent should be miscible with water to allow a homogeneous mixture to be prepared and maintained without the use of excessive stirring.

The same solvent could be used in the homogeneous mixture of the solvent and for any subsequent washing treatment, or a solvent could be used in the pretreatment and another solvent or optionally more than one solvent or a mixture of two or more solvents could be used for the treatment of washed.

The solvent could be a monohydric alcohol, for example methanol, ethanol, isopropanol, tert-butanol, sec-butanol, n-butanol, tert-amyl alcohol, neopentyl alcohol, sec-amyl alcohol or diethyl-ilcarbinol; a dihydric alcohol, for example ethylene glycol, propylene glycol or tetramethylene glycol; a ketone, for example acetone, methyl ethyl ketone, methyl iso-butyl ketone or methyl tert-butyl ketone; or a glycol ether, for example diethylene glycol monomethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether or triethylene glycol dimethyl ether.

The weight ratio between the solvent or solvent mixture and water in the pretreatment mixture is appropriately 40:60 to 80:20 such as 50:50 to 70:30. When 'water' refers to, in connection with the ratio between the solvent and water in the reaction mixture, the amount of water is the sum of water added and the water present in the initiator material containing pectin.

According to the invention, the pre-treatment of the pectin-containing material is carried out for a period of 2 to 6 hours p. ex. from 3 to 4 hours.

The acids used in the pretreatment include organic acids and inorganic acids such as an inorganic acid selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid and nitric acid. Among these acids, it is currently considered that nitric acid and hydrochloric acid are particularly used.

The drying step is carried out by means of any conventional drying equipment such as a drying oven, a band dryer, a drum dryer or a fluid bed dryer for a period of time sufficient to obtain a content of material dry in the material of at least 80% by weight, preferably at least 90% by weight. The drying is carried out at a temperature in the range of room temperature to about 100 ° C, preferably at a temperature in the range of 40 ° C to 100 ° C, for a period of at most 36 hours. It may be preferred to carry out the drying at pressures below the atmospheric pressure, whereby a relatively lower drying temperature or a comparatively shorter drying period can be used which results in a milder treatment.

In food applications the highly esterified pectin fractions provided by the method of the present invention have, as mentioned above, significant advantages over the pectin products provided by the bulk extraction.

With respect to the functionality characteristics of such selected pectin fractions, the adjustment time as defined above is a significant parameter. According to the method of the invention, the pectin fractions can be obtained which p. ex. they have an adjustment time in the range of 0 to 100 sec, 101 to 200 sec, 201 to 300 sec or in excess of 300 sec, respectively.

In one aspect, the present invention relates to the use of highly esterified pectin fractions obtained by the method for preparing such fractions of the present invention in the preparation of a food product.

In the presently preferred embodiments of the invention, the food product in the preparation of which highly esterified pectin fractions are used, is selected from the group consisting of acidified dairy products p. ex. which have a pH of 3.5 to 4.5, such as yogurt for drinking and yogurt with fruit and preserves, such as jam and jellies and fruit and vegetable juices.

The above acidified dairy products comprise dairy products obtained by acidification either by fermentation with bacteria that produce live acid or by the addition of fruit juices or food acids.

During the acidification of the milk, the pH passes the isoelectric pH value of caseins and the net charge becomes positive. A three-dimensional casein network is created and the milk is changed to a gel. The agitation of the milk gel breaks the structure and the acidified milk is converted to liquid. However, the net positive charge on the net surface of the caseins can not sufficiently prevent the agglomeration of the caseins and the acidified milk will therefore be physically unstable with respect to the sedimentation and separation of the whey. The addition of a highly esterified pectin provided by the method of the present invention will prevent these undesirable physical changes in the acidified milk ingested in a more effective manner than a pectin extracted in bulk.

In this way, it was found that the addition of a pectin fraction according to the invention to the drinking yoghurt, resulted in an improvement of this dairy product, including at least 10% reduction in viscosity, at least 50% of particles smaller or at least 10% less sediment, compared to the addition of the same amount of a pectin product extracted in bulk. More specifically, it was found that the addition of a pectin fraction as provided herein and having} an adjustment time in the range of 100 to 200 sec to the drinking yoghurt compared to the addition of the same amount of a commercially extracted pectin product in bulk that also has an adjustment time in the range of 100 to 200 sec, resulted in a significant reduction in viscosity such as at least a 2-fold reduction (< 50%), e.g. ex. at least a 5-fold reduction (< 20%), a significant reduction in particle size that could be at least 2 times smaller, e.g. ex. at least 5 times smaller or even at least 10 times smaller, and much less sediment that includes at least 2 times less sediment, which includes at least 5 times, p. ex. At least 10 times less sediment.

During their experimentation, the inventors have found that the selected pectin fractions obtained by the consecutive acid extraction of a pectin-containing plant material by the methods as described above, are very suitable starting materials for the preparation of derived pectin fractions. which have exceptionally good functional characteristics. In this way, the highly esterified pectin fractions according to the invention are subjected to reactions involving treatments with an agent capable of desestifying a highly esterified pectin such as a deesterified acid and / or ammonia and optionally obtaining amidated pectin fractions. which are useful as additives in various food products such as, for example, fruit preparations and dairy products. It has been found that such deesterified pectin fractions with respect to the functional properties generally perform similarly as the desesified pectin products which are prepared from pectin extracted in bulk.

Therefore, the present invention relates in a further aspect to a method for obtaining de-esterified pectin fractions having improved functional characteristics, comprising subjecting the selected pectin fractions obtained by consecutive acid extraction of a pectin-containing plant material as Desensitization was described above by at least one step of treatment with an acid and / or ammonia to obtain a pectin fraction having a degree of sterolification (GE) that is reduced by at least 5% relative to that of the highly esterified pectin fraction and a degree of amidation (GA) that is in the range of 0-25.

In the embodiments used, the resulting de-esterified fraction has a GE that is at most 70% such as less than 60%, which includes less than 50%, such as less than 45%, p. ex. a GE in the range of 20-45.

In accordance with this aspect of the invention, the deesterified pectin fractions can be obtained either by deesterification of a highly esterified pectin fraction under acidic conditions, or the highly esterified pectin fraction could be deesterified by initially treating it with an acid and subsequently desterifying it under Basic conditions treating the deesterified fraction of the acid with ammonia, or the highly esterified pectin fraction could be deesterified exclusively under basic conditions by treatment with ammonia. The acid that is used in this method is preferably a strong inorganic acid such as HCl, H2SO4, H3PO3 or HNO3, or an organic acid such as for example oxalic acid or formic acid.

Although it is preferred to use an acid in the deesterification step, the use of a base such as alkali metal hydroxides or carbonates is not excluded.

In an interesting embodiment of the method, deesterified pectin fractions having an esterification degree that is less than 60% and an amidation degree that is 0, are obtained by the above deesterification treatment. Such de-esterified pectin fractions are very suitable for further desesification under basic conditions by treatment with ammonia.

According to the invention, the de-esterification comprises in a currently preferred embodiment the thermal treatment of an aqueous solution or suspension of a highly esterified pectin fraction in the presence of a strong inorganic or organic acid added to give a pH less than 1. The treatment The thermal fraction of the selected pectin fraction is carried out at a temperature in the range of 40 to 80 ° C for a period of 1 to 50 hours. In appropriate embodiments, the deesterification step is carried out at a temperature in the range of 45 to 55 ° C for a period of time which is 4 to 20 hours, such as 10 to 20 hours or 4 to 10 hours. hours.

In this connection, the acids used include inorganic acids as exemplified by, but not limited to, hydrochloric acid, sulfuric acid and nitric acid, and organic acids, such as formic acid and oxalic acid. It will be understood that mixtures of acids could also be used in the desesification reaction.

The amount of acid to be added to the deesterification mixture to obtain convenient acidification in the mixture during the reaction is typically in the range of 0.005 to 0.015 moles per gram of pectin to be desensitized and the amount of dry matter of Pectin present in the reaction mixture (desterification mixture) is typically in the range of 1 to 5% such as 1 to 3% by weight of the reaction mixture.

Deesterified pectin fractions are typically recovered from the reaction mixture by adjusting the pH of the mixture to a value in the range of 3 to 5 such as from 4 to 5 by the addition of a base, such as for example ammonia, followed by the precipitation of the pectin in an organic solvent miscible with water or, as an alternative, in a homogeneous solution of an organic solvent miscible in water and water.

The precipitated pectin is separated from the liquid by any convenient method, such as by filtration or centrifugation, and the precipitate is pressed and washed on the filter to remove salts and soluble impurities. Finally, the pectin is dried and optionally ground to form a powder.

The organic solvent used could be any solvent miscible in water in which the pectin is substantially insoluble. A suitable solvent could be any of the solvents mentioned above such as a monohydric alcohol, a dihydric alcohol, a ketone, a glycol ether and mixtures thereof. A presently preferred solvent is isopropanol.

A highly esterified selected pectin fraction of the invention could also be deesterified under basic conditions by treating the selected pectin fraction with ammonia. Under these conditions, part of the methoxyl groups in the pectin molecules to be de-esterified are replaced by OH groups and part of the methoxyl groups are replaced by the NH2 groups. Thus, the deesterification reaction results in a deesterified pectin fraction containing the amide groups, for example amidated pectin. In such fractions of the desidated amidated pectin the ratio between the degree of desessification and the degree of amidation is preferably at least 0.75, such as in the range of 0.75 to 2.00 including the range of 1.0 to 1.5, for example in the interval from 1.0 to 1.2.

Thus, in another embodiment of the method, a pectin fraction having an amidation degree in the range of 5 to 25 including the range of 15 to 25 is obtained.

The initiator material for basic desessification, as mentioned above, could be a selected highly esterified pectin fraction according to the invention. However, a highly esterified selected pectin fraction can be used which has first been deesterified under acidic conditions with a strong acid as described above.

The basic desesterization reaction is carried out in a suspension of the initiator material of the pectin fraction in a homogeneous aqueous solution containing an organic solvent miscible in water in the presence of ammonia. During the reaction the pectin to be deesteri fi ed is present in a partially hydrated and dilated state which is a prerequisite for a convenient course of the reaction. A partially hydrated and dilated state of the pectin is achieved when the amount of organic solvent used in the aqueous-organic solvent solution is in the range of 30 to 80% by weight, for example in the range of 35 to 50% by weight.

The organic solvent used could be any water-miscible solvent in which the pectin is substantially insoluble. A suitable solvent could be any solvent that has been mentioned above, such as a monohydric alcohol, a dihydric alcohol, a ketone, a glycol ether or mixtures thereof. A presently preferred solvent is isopropanol.

The basic deesterification is typically carried out at a temperature in the range of 0 to 30 ° C for a period of 2 to 8 hours.

The amount of added ammonia used in the reaction mixture is usually in the range of 0.005 to 0.02 moles such as for example 0.010 to 0.015 moles per grams of pectin to be descretized. The amount of dry matter of the pectin fraction in the suspension is typically in the range of 10 to 30% by weight including an amount in the range of 15 to 20% by weight of the suspension.

It has been surprisingly found that basic deesterification with ammonia is affected by the presence of alkali metal ions. In this way, it has been found that the presence of sodium ions accelerates deesterification and the potassium ions decrease the reaction compared to a reaction carried out under identical conditions except that no alkali metal ions have been added. Also the lithium ions have an effect of increasing the speed.

This offers an additional reaction parameter in addition to, for example, the reaction temperature and the reaction time to control the deesterification reaction.

Therefore, in a particular embodiment of the invention, basic deesterification with ammonia is carried out in the presence of an alkali metal cation resulting from the addition of a water-soluble neutral alkali metal salt, such as example a lithium, sodium or potassium chloride, bromide, sulfate or nitrate.

The deesterification reaction with ammonia is quenched by pouring the reaction mixture into a homogeneous mixture of a water-miscible organic solvent as mentioned above, and water followed by adjusting the pH to a value in the range of 4 to 5 by addition of an acid such as, for example, hydrochloric acid, sulfuric acid or nitric acid.

As an alternative, the reaction is turned off by first adjusting the reaction mixture to a pH value in the range of 4 to 5 by the addition of an acid and then pouring the neutralized reaction mixture into a homogeneous mixture of an organic solvent miscible with the reaction mixture. water and water As another alternative, the reaction mixture is separated by filtration, and the ammoniacal filtrate is poured into the homogeneous mixture of the organic solvent and water to obtain a precipitate of the de-esterified pectin. This alternative makes it possible to reuse the ammonia-containing liquid that remains after the precipitate has separated.

The pectin is separated from the liquid by any convenient method, such as, for example, by filtration or centrifugation, and the pectin is pressed and washed to remove the substances and the soluble impurities. Finally, the isolated de-esterified pectin material is dried and optionally, the dried material is ground to obtain a powder.

The fraction of pectin desesterified according to the invention, preferably has a degree of esterification which is at most 45% including at most 40%. A preferred degree of amidation is in the range of 5 to 25.

The deesterified fractions used have a ratio between the degree of esterification and the degree of amidation in the resulting de-esterified pectin fraction of at least 0.75, such as in the range of 0. 75 to 2.00 including the interval from 1.0 to 1.2.

The de-esterified pectin fraction is useful in the preparation of food products as a gelling or thickening agent. In this way, it could be used in the elaboration of fruit-based products including preserves, jams, gelatins, pastry product fillings or dairy products.

The invention is further described in the following examples which are not intended to be in any way limiting the scope of the invention as claimed.

EXAMPLES MATERIALS AND METHODS Determination of the degree of esterification (GE), degree of amidation (GA) and anhydrogalacturonic acid (AUA).

The GE, GA and the total anhydrogalacturonic acids were determined according to the procedures given in Food Chimecal Codex, Third Edition, National Academic Press, Washington 1981, page 216.

Determination of reduced viscosity An amount of pectin corresponding to 90 mg of pectin dry matter is weighed into a 150 ml Erlenmeyer flask together with 100 g of buffer solution which is prepared by dissolving 1 g of sodium hexametaphosphate in distilled water and the pH is adjusted to the value of 4.5 with a few drops of 4 N hydrochloric acid. After a few hours of stirring, the pectin is dissolved. If the solution is not clear, it is filtered through a filter crucible with porosity 2. Drip periods of the resulting pectin solution and the buffer solution are measured, respectively, at 20 ° C in a drop ball viscometer (Hoeppler viscometer) ).

The specific viscosity is:? Sp = (drip period for the pectin solution / drip period for the buffer) -1 The reduced viscosity is? .ed =? _P / C =? Sp / l (L / g) Determination of US-SAG ° The SAG value expresses the ability of the pectin to interact, mainly through hydrogen bonding, with sugar in a sugar gel that completely gels. "The SAG value is a measure of gel strength (gel strength), without breaking the gel, and was determined according to the IFT SAG method as described 'in Food Technology, 1959, 13, 496-500.

Determination of the adjustment time The adjustment time of the pectin fractions was determined according to the method described by G. H. Joseph and W. E. Bair (Food Technology, 1949, 18, 18-22).

Determination of the degree of viscosity (Visc °) The viscosity grade (Visc °) refers to 0.6 g of an ideal viscosity pectin of 40 centipoise (cP) in a 0.6% weight aqueous solution under the specified measurement conditions.

The viscosity grade of a pectin sample is determined by measuring the viscosity of the solutions of different pectin concentration by means of a Haake VT 181 viscometer at speed 4 and at a temperature of 25 ° C. Graphing the measured values in a semi-log diagram is the amount (A) of the pectin that gives a viscosity of 40 cP. The viscosity grade (Vise0) is 0.6 x 100 / A.

Determination of the gelling force The strength of the gelatin and breaking force is determined in a test gel by determining the force necessary to drag an open plastic body out of the gel.

The test gel was prepared from 216 g of sugar 147 g of buffer solution pH 3.0 (lactic acid, potassium acetate, water) 0.845 g of pectin (= 0.25%) 0.1 g of antifoaming agent The breaking strength of the test gel is measured by means of a Herbstreith Mark III Penetinometer and is indicated in Herbstreith Pektinometer units (HPU).

EXAMPLE 1 600 g of dried lemon peel having a dry matter content of 91.3% was suspended in 9000 g of deionized water and the suspension was heated to a temperature of 70 ° C with gentle agitation. By adding nitric acid (69%) the pH was adjusted to 2.5. The suspension was gently stirred for 2 hours at 70 ° C after which the liquid was separated from the peel extracted in a screen and the liquid was filtered on a nylon cloth covered with Celite 545. The extracted pectin was precipitated by pouring the filtrate clear in two volumes of isopropanol with stirring. The precipitated pectin was separated by draining on a filter and washed with a 60% (w / w) isopropanol / water mixture. After draining and pressing on a cloth, the wet pectin was dried overnight in a drying oven at 40 ° C. The dried pectin was ground to a fine powder. The pectin production was 44.4 g (Fraction 1).

The peel residue from the first extraction was subjected to a second extraction by suspending the shell residue in deionized water to a total weight of the suspension of 9000 g, heating the suspension to 70 ° C with gentle agitation. By adding nitric acid the pH of the mixture was adjusted to 1.7. The mixture was stirred for two hours at a temperature of 70 ° C after which the pectin extract was separated from the material of the solid shell. The extracted pectin was recovered from the extract as described above. The dry pectin production was 51.8 g (Fraction 2).

The residue from the shell of the second extraction was subjected to a third extraction by suspending the shell residue in deionized water to a total weight of the suspension of 9000 g, heating the suspension to 70 ° C, adding nitric acid to pH 1 and stirring the mixture for one hour at a temperature of 70 ° C. The extracted pectin was recovered as described above for the first and second extraction. The production of dry pectin was 23.5 g (Fraction 3).

To remove the calcium present in the isolated pectin, the recovered pectin was suspended in 10 parts by weight of 60% (w / w) isopropanol / water mixture containing 3% HCl, stirred for 15 minutes, separated by filtration and washed on a filter with 60% (w / w) isopropanol / water mixture until the filtrate was chloride free. Finally, the pectin was suspended in 10 parts by weight of 60% (w / w) isopropanol / water mixture containing 0.5% weight of ammonia, separated by filtration, washed on a filter with isopropanol / water mixture at the 60% (w / w) and dried.

The analytical characteristics of the pectin fractions are shown in the following Table 1.1.

TABLE 1.1 EXAMPLE 2 Extraction of lime peel 2. 1. Pre-treatment of the skin 268 g of lime peel having a dry matter content of 90.3% weight was suspended in 2950 g of a 40% (w / w) isopropanol / water mixture. The suspension was heated to a temperature of 70 ° C and by the dropwise addition of nitric acid (35%), the pH was adjusted to 1.4. After having stirred at a temperature of 70 ° C for 3 hours, the shell material was separated from the reaction mixture by filtration on a nylon cloth. The solid material of the shell was pressed / squeezed to remove as much liquid as possible. The material of the separated shell was dried overnight at a temperature of 40 ° C. 2. 2. Extraction of the pre-treated lime peel The pre-treated and dried lime peel was suspended in 8 kg of an aqueous solution containing calcium chloride (15 mmol / l). The suspension was heated to a temperature of 60 ° C and the pH adjusted to 4 by the addition of ammonia. The material of the shell was removed for 4 hours, while the suspension was stirred, after which the liquid pectin extract and the solid extraction residue were separated by filtration on a nylon cloth.

The pH of the pectin extract was adjusted to 2 by the addition of nitric acid and subsequently the pH was raised to about 3 by the addition of a cation exchange resin (Amberlite 200) in the Na + form. The mixture was stirred at room temperature for 2 hours. The cation exchange resin was removed by filtration and the pectin was precipitated by pouring the filtrate into 12 kg of isopropanol while stirring. The pectin was separated from the liquid by filtration on a nylon cloth, squeezed and washed on the filter with 60% (w / w) isopropanol / water mixture. The pectin was dried overnight at a temperature of 40 ° C. The pectin production was 36.5 g (Fraction 1).

The solid material from the shell of the first extraction was subsequently subjected to a second extraction by suspending it in 8 kg of an aqueous solution containing calcium chloride (15 mmol / 1). The suspension was heated to 60 ° C and the pH adjusted to 1.7 by the addition of citric acid. The shell material was extracted for 4 hours, after which the pectin extract was separated from the solid material by filtration. The pectin was recovered as described above for the first pectin extract. The production was 11.4 g (Fraction 2).

The analytical characteristics of the pectin fractions are shown in Table 2.1 below.

TABLE 2.1 EXAMPLE 3 Extraction of the lemon peel 300 g of dried lemon peel, was suspended in a mixture of 7200 g of deionized water and 14.3 g of 68% nitric acid and stirred gently for 3 hours at 70 ° C at a pH of 2.4. Then the liquid was separated from the extracted shell by draining through a stainless steel screen with 1 mm of opening. The residue of the shell was washed for one and a half hours by suspension in 2000 g of water at 70 ° C and then drained again.

The residue of the moist shell (2458 g) from the first extraction was subjected to a second extraction by suspension in 2750 g of water with the addition of 8.04 g of 68% nitric acid. The mixture was stirred gently for 3 hours at 70 ° C at pH 1.80. The shell residue was separated on the screen and subjected to a third extraction with 1800 g of water and 4.48 g of 68% nitric acid for 1 hour at 80 ° C at a pH of 1.5. The extraction mixture was then separated on the screen and the residue of the shell was washed twice with 1200 g of water each at 80 ° C for 1.5 hours.

The extracts from the first extraction and from the next wash were combined and purified by filtration through a vacuum filter covered with diatomaceous earth. The clear filtrate was concentrated by evaporation in vacuo and the viscous concentrate precipitated by stirring in two portions of 85% isopropyl alcohol. Then the precipitated pectin was separated by draining on a filter and washed with 60% volume isopropyl alcohol. The pH was adjusted to approximately 3.5 by the addition of 20% sodium carbonate. After draining and pressing on a cloth, the pectin was dried in a drying oven at 40 ° C overnight. The dried pectin (Fraction 1) was ground to a fine powder.

The extracts of the second and third extractions and the following washes were combined and the. Pectin (Fraction 2) was isolated in a similar manner.

The productions and analyzes of the two pectin fractions are shown in Table 3.1.

TABLE 3.1 EXAMPLE 4 Extraction of lime peel 4. 1. Pre-treatment of lime peel 134 g of dried lime shell material (dry matter content 90.3% by weight) was suspended in 1475 g of 40% w / w isopropanol / water mixture in a 5 liter glass reactor. The suspension was heated to a temperature of 70 ° C for 3.5 hours under continuous stirring, while maintaining the pH in the suspension at a level of approximately 2 (1.7-2.1) by the addition of nitric acid (35%). The material of the shell was separated from the reaction medium by filtration on nylon cloth. The reaction medium had a green appearance, with a content of dense hazy substances. The material of the separated shell was dried overnight at a temperature of about 40 ° C. The production of the dried, pre-treated lime shell material was 114 g (85%) which had a GE of 71.5 and an AUA content of 44.9%. 4. 2. Extraction of the pre-treated lime peel The dry material of the lime shell (114 g) of the previous pre-treatment was suspended in 4000 g of an aqueous solution containing calcium chloride (30 mmol / l) and the pH of the suspension was adjusted to 4 by the addition of ammonia. The suspension was heated to a temperature of 70-72 ° C for 17 hours under permanent stirring, after which the liquid solution and the solid extraction residue were separated by filtration on a nylon cloth.

The pH of the extract was adjusted to 2.2 by the addition of nitric acid (35%). The pH of the solution was increased to 2.8 by the addition of a strongly acidic cation exchange resin (Amberlite 200) in the Na + form, after which the extract was stirred at room temperature for 5 hours. The ion exchange material was separated by filtration. Isopropanol (2 parts of IPA per 1 part of the filtrate) was added to the filtrate to precipitate the pectin which was recovered by filtration and dried overnight at a temperature of 40 ° C. The production of pectin (sodium salt) was 15.5 g (Fraction 1), which had the following characteristics: GE of 77.2, AUA% of 77.3, US-SAG of 234 and an adjustment time of 30 sec.

The solid extraction residue, which was separated from the extract, was dried overnight at a temperature of about 40 ° C. The production was 98.5 g of partially extracted lime peel that had the following characteristics: Degree of esterification 67.5 and% AUA 35.7.

The partially extracted lime shell material (98.5 g) from the first extraction was suspended in 4000 g of deionized water. The suspension was acidified to pH 2 by the addition of nitric acid (35%) and heated to a temperature of 70 ° C for about 15 hours under continuous stirring. The reaction mixture was separated by filtration in a solid extraction residue and the liquid fraction contained the extracted pectin. The pH of the extract was adjusted to 2.3 by the addition of nitric acid, and by the addition of the Na + form of a strongly acidic cation exchange resin (Amberlite 200) the pH was raised to 3.2. The mixture was stirred for 6 hours at room temperature, after which the ion exchange resin was separated by filtration and the pectin was precipitated by the addition of isopropanol to the filtrate. The pectin was collected by filtration, washed twice with 60% (w / w) isopropanol / water mixture and dried overnight at a temperature of 40 ° C. The production of pectin (sodium salt) was 13.2 g (Fraction 2).

The analytical characteristics of the fractions of the recovered pectin are shown in Table 4.1 below.

TABLE 4.1 EXAMPLE 5 Preparation of yogurt to drink The pectin fraction 2 of Example 1 above was tested in a drinking yoghurt system having the following composition: Yogurt base 489 g Sugar 44 g Water 14.2 g Pectin x g Dextrose 2.8 - x g For comparison purposes, a commercial bulk pectin from Danisco Ingredients, Brabrand, Denmark was used with the following characteristics: GE of 70.0,% AUA of 82.9, US-SAG ° 235 and adjustment time of 130 sec. In the following, this pectin product is also referred to as 'reference'.

The yogurt base was 'Letmaelks Yoghurt Naturel' (Klover Maelk, Denmark) which has a fat content of 1.5%, an MSNF content of 9% and a pH of 4.3.

The base of the yogurt was stirred for 15 minutes, with a high speed mixer to break the gel structure and to make the yogurt liquid. The pectin was mixed dry with dextrose and sugar and the pectin-sugar mixture was slowly added to the yogurt base while the yogurt mixture was stirred. Water was added and stirring was continued for another 15-20 minutes.

The yoghurt beverages were homogenized at 200 bar at room temperature and filled into glass bottles. The yoghurt drinks were then heat treated for 20 minutes in a water bath at a temperature of 75 ° C. The bottles were shaken vigorously every 5 minutes. The samples were cooled to room temperature and kept overnight at 5 ° C.

The physical quality of a yogurt drink could be characterized by the viscosity and particle size distribution of the beverage.

Frequently a low viscosity is preferred than a high viscosity of a yoghurt drink. The composition of the yogurt drink and the process by which the viscosity has been influenced, but the pectin and the dosage of the pectin used for the stabilization will also affect the viscosity. If the pectin has been added to insufficient concentrations for stabilization or has been added to excess concentrations, the viscosity will be greater than the optimum concentration of pectin. The optimum concentration of the pectin is characterized by the lowest possible concentration of the pectin sufficient for the stabilization of the beverage. At this concentration, the viscosity of the yogurt drink will be minimal.

The viscosity was measured by means of a Brookfield Viscometer (model LVTDV-II) at a speed of 30 rpm using non-shaft rods. 6.1 or 6.2. The yoghurt drink (350 ml) was poured into a 400 ml glass beaker and warmed to a temperature of 10 ° C. The viscosity was read in centipoise (cP) after an equilibrium time of 30 seconds. The measurements were made after 1 day of storage of the yoghurt drinks. The results are shown in Table 5.1.

The particle size distribution was measured by means of a Malvern S Master Meter using a citrate-phosphate buffer with pH 4.2 and the standard 30HD presentation model. The determination was based on the average of a double determination and is reported as the average volumetric particle size D (v, 0.5). The measurements were made after 1 day of storage of the yoghurt drinks. The results are shown in Table 5.1.

The physical stability of the yoghurt beverages was evaluated by an accelerated test exposing the beverages to various mechanical stresses by centrifugation after 1 day of storage.

The accelerated sedimentation test was carried out by means of a Varifuge 3.2S. Approximately 40 g of yoghurt drink was weighed in a 50 ml centrifugal glass. The sample was centrifuged at 3500 rpm for 2 minutes at room temperature. The supernatant was removed and the glass left up for 5 minutes before the remaining pellet was weighed.

The sediment was calculated and expressed in% weight based on duplicate determinations: % of sediment = weight of sediment x 100 / weight of the sample The results are shown in Table 5.1. For a yogurt drink that is physically stable throughout the shelf life, the% sediment value should be lower, preferably less than 5% by weight.

TABLE 5.1 The pectin fraction 2 is very suitable for the stabilization of the yoghurt drink. The pectin stabilizes the pasteurized yogurt drink with approximately 0.15% weight of pectin whereas the pectin extracted in bulk from the previous reference of Danisco Ingredients needs to be dosed in an amount of approximately 0.25% weight before the yogurt is stable.

Furthermore, with fraction 2 of pectin dosed at its optimum concentration of 0.15% by weight, the viscosity of the yoghurt drink is only 29 cP, while the viscosity of the yoghurt beverage containing the optimum concentration of 0.25% by weight of pectin extracted in bulk reference is 57 cP.

EXAMPLE 6 Pre-treatment of lime peel and extraction of pre-treated lime peel 268 g of lime peel (dry matter content 90.3% by weight) was suspended in 2950 g of a 40% isopropanol solution in water in a 5 liter three neck glass flask. The suspension was heated to 70 ° C and 42.5 g of 35% nitric acid was added dropwise to obtain a pH of 1.6. The suspension was stirred at a temperature of 70 ° C for 3 hours.

The material of the pre-treated shell was separated from the liquid filtration in a nylon cloth. The material was squeezed to remove as much liquid as possible and the material was dried at a temperature of 40 ° C overnight giving approximately 200 g of the pre-treated shell material.

The material of the pre-treated lime shell was extracted as described in Example 2 to obtain a first fraction of pectin having a GE of 74.1 and Vise "of 74, and a second fraction of pectin having a GE of 60.4 and Vise0 of 31.

EXAMPLE 7 Acid deesterification of a selected first pectin fraction g of the first pectin fraction selected from Example 6 was suspended in 1470 g of deionized water in a 3-liter three neck glass flask and stirred using an Ultra Thurax mixer at maximum speed until a homogeneous solution was obtained .

The solution was heated to 73 ° C and 65.2 g of nitric acid (35%) was added to obtain a pH of 0.6. The mixture was stirred at 73 ° C for 5.0 hours followed by adjusting the pH of the mixture to 4 with the addition of ammonia solution and without further cooling, the mixture was precipitated in 3000 g of 60% isopropanol solution in water while it was shaking gently.

The precipitate of the desesified pectin was removed by filtration using a nylon cloth and the material was squeezed to remove as much liquid as possible. The separated pectin was washed twice in the filter with isopropanol-water solution to remove the salts. The washed material was dried at 40 ° C overnight and ground in a Retsch mill to give a powder with a particle size smaller than 0.5 mm and having a GE of 34.7 and Vise0 of 21.7.

EXAMPLE 8 Acid de-esterification of a second selected pectin fraction g of the second pectin fraction selected from Example 6 is substantially de-esterified as described in Example 7 using 67.1 g of nitric acid at 60 ° C for 8.8 hours to give one. De-termed pectin having a GE of 35.6 and a Vise "of 21.2.

EXAMPLE 9 Application of a desiccated pectin fraction with acid in a pastry filling The deesterified pectin fraction of Example 7 was tested in a high sugar confectionery filling against a lime pectin extracted in bulk which is desessed following the same procedure as described in Example 7 to give a pectin product in bulk desi fied with a GE of 34.5 and a Visc ° of 35.

A confectionery filling is defined as a filling comprising mainly fruit, sugar, water, acid and stabilizer which is intended for use in confectionery products such as cakes, cookies, pies, etc. and the filling is done in the cake. A pastry filling is not a gel, but a pre-gelled system.

The pastry filling was prepared according to the following procedure Raspberry (300 g), sugar (435.5 g) and glucose syrup (150 g, 42 GE, 75% SS) were added to a 1 kg Fizzler vessel (equipped with an agitator) and heated. The weight of the mixture was reduced to 770 g by boiling.

The pectin (12 g) was dissolved in warm deionized water (80 ° C) (200 g) while stirring and the pectin solution was added to the fruit / sugar solution in the container, stirring continuously.

The solution should have a temperature of 85 ° C.

Calcium citrate (2 g) was mixed dry with sugar (60 g) and boiling, deionized water (40 g) was added to the mixture of calcium citrate and sugar to make a suspension. The suspension (temperature: 88-90 ° C) was added to the vessel while stirring vigorously and holding the vessel at a temperature of 80 ° C.

Potassium sorbate (2 g) and sodium benzoate (3 g) were added, and the pH was adjusted to 3.6 with citric acid / sodium citrate.

The mixture in the vessel was cooled from 80 ° C to the filling temperature (40 ° C) and filled into the molds.

Three different pastry tests were done to. In biscuits, 200 ° C for 10 minutes. b. In biscuits, 200 ° C for 15 minutes. c. In aluminum dishes, 220 ° C for 10 minutes. a and b: A sample of the pastry filling was poured into a standard mold (d = 75 mm, h = 10 mm) and placed in the center of the blister. The surface was scraped horizontally with a knife and the mold was carefully removed. The bísquets were made on a pastry plate at a temperature of 200 ° C for 10 and 15 minutes. c: A sample (20 g) of the pastry filling was pumped half round a round aluminum plate (d = 75 mm). The aluminum plates were placed in a pastry dish and were made at a temperature of 220 ° C for 10 minutes.

The evaluation of the pastry tests is shown in the following Table 9.1 TABLE 9.1 EXAMPLE 10 Acid deesterification combined with basic deesterification of a selected first pectin fraction 80 g of a first highly esterified pectin fraction obtained as described in Example 4 and having a GE of 73.8, a Visc ° of 72.4, a SAG ° of 246 and an adjustment time of 47 sec, was suspended in 3920 g of deionized water in a 5 liter glass reactor. The suspension was stirred with an Ultra Thurax agitator at maximum speed until a homogeneous solution was obtained. The solution was heated to a temperature of 45 ° C and 200 g of nitric acid (35%) was added while stirring gently. The solution was stirred for 17 hours at a temperature of 45 ° C.

The pH of the reaction mixture was adjusted to 4 by adding ammonia solution and the mixture was precipitated in 8000 g of isspropanol. The precipitated pectin was separated from the reaction mixture by filtration on a nylon cloth. The separated pectin was pressed / squeezed to remove as much liquid as possible and washed twice with 60% isopropanol-water solution. The pectin was dried at 40 ° C overnight. The dried pectin was ground in a Retsch mill to obtain a powder having a particle size of less than 0.25 mm and a GE of 55.7 and Visc ° of 63. g of the above deesterified pectin fraction was suspended in a solution of isopropanol (77.9 g), water (91.4 g) and ammonia (7.7 g) at a temperature of 0 ° C and the suspension was stirred vigorously at a temperature in the range of 0 ° C to 4.5 ° C for 3.7 hours.

The amidation reaction was quenched by pouring the reaction mixture into 200 g of 60% isopropanol-water solution and adjusting the pH to 4.4 by adding nitric acid.

The amidated material was filtered off and washed free of salts with 60% isopropanol-water solution and dried at 40 ° C overnight. The dried material was ground to obtain a powder having a particle size less than 0.25 mm. The de-esterified pectin fraction had a GE of 29.6% and an amidation grade (GA) of 21.2%.

EXAMPLE 11 Acid deesterification combined with basic deesterification of a selected first pectin fraction Following the procedure as described in Example 10, except that the acid deesterification was carried out at a temperature of 53 ° C for 13 hours, which gave a product having a GE of 53.1 and a Visc ° of 56, and the amidation time was 4.7 hours, a pectin fraction was obtained that had a GE of 25.1 and a GA of 22.5.

EXAMPLE 12 Acid deesterification combined with basic deesterification of a second selected pectin fraction 80 g of a second pectin fraction obtained as described in Example 4 had a GE of 64.1, a Visc ° of 55, a SAG of 256 and an adjustment time of 213 sec, was suspended in 3920 g of water in a 5-liter glass reactor. The suspension was stirred with an Ultra Thurax agitator which operated at maximum speed until a homogeneous solution was obtained.

The deesterification was carried out substantially as described in Example 10 with the modification that the reaction was carried out at a temperature of 53 ° C for 5.1 hours, to provide a pectin fraction which had a GE of 55.5 and a Visc ° of 51.7.

Following the same procedure as described in Example 10, the de-terminated pectin fraction was subjected to amidation at a temperature in the range of 0 to 4.5 ° C for 3.0 hours to obtain a fraction that had a GE of 29.4 and a GA of 21.5.

EXAMPLE 13 Acid deesterification combined with basic deesterification of a second selected pectin fraction Following the procedure as described in Example 11, except that the amidation time was 3.5 hours, a desesified pectin fraction having a GE of 27.3 and a GA of 22.9 was obtained.

EXAMPLE 14 Acid deesterification combined with basic deesterification of a pectin extracted in bulk The pectin extracted from lime bulk was desessed and subjected to amidation following the same procedures as described in Examples 10 and 11 to obtain a pectin material extracted in bulk having a GE of 29.7 and a GA of 21.0.

EXAMPLE 15 Measurement of the viscosity profiles (Brabender test) for the pectin fractions of Examples 10-14 The gelation behavior under cutting conditions of the amidated pectin fractions obtained in Examples 10, 11, 12, 13 and 14 respectively, was recorded by means of Brabender E Viscometer (model 8025) which is a rotational viscometer consisting of a basic unit, control unit and a continuous line recorder for torque (viscosity) and temperature.

The Brabender measurement in a gelation system as a function of temperature visualizes the development of the viscosity in the system of a visco-elastic (high temperature) system via gelation to gel the resulting cracks in the formation of a paste due to to the cutting efforts. In this way, the Brabender test is a very appropriate method for characterizing food preparations, such as for example fruit preparations, to obtain a better understanding of the functionality of pectin in such systems.

The gelling behavior of the pectin to be tested was examined in a model system (= an artificial fruit preparation), having pH 3.5 and containing 38% soluble solids, consisting of: sugar sample at 37.0% by weight , water at 28.4% by weight, pectin at 0.6% by weight to be tested, CaCl2-2H20 at 0.7% by weight and 34.0% by weight of aqueous buffer (pH 3.8) containing per liter: 1. 95 g of tripotassium phosphate (K3P04, H20), 6.33 g of tripotassium citrate (K3C6H5? 7, H20), 0.82 g of trisodium citrate (C6H5Na3? 7, 2H20), 1.19 g of tricalcium dicitrate (C? 2H10Ca3O14) , 4H20), 2.02 g of magnesium acetate (C4H6Mg04, 4H20), 1.00 g of sodium benzoate (C6H5Na02) and 14.0 g of citric acid (C6H807).

This system was prepared at a temperature of about 80 ° C by dissolving the pectin sample, dry mixing with part of the sugar (60 g), in hot demineralized water (80 ° C) and when these components dissolved, the rest of the Sugar was added and dissolved in the hot solution. Then calcium chloride was added followed by the addition of the buffer solution. Finally, 4.5 ml of IN hydrochloric acid was added.

The viscography test was carried out with or The test solution (514 g) was placed in the measuring bowl of the Brabender viscometer, and the temperature of the solution was adjusted to 80 ° C by heating. After a retention time of 5 minutes at 80 ° C, the solution was cooled at a constant rate of 1 ° C per minute while rotating the measuring bowl at a speed of 50 rpm. During the measurement, the current values of the torque (viscosity) and temperature were recorded. Torca (viscosity) is given in BU (BRABENDER units). The results are shown in Table 15.1.

TABLE 15.1 Mués tr% GE% GA Viscosity Brab snder a Temperature interval a ° c temp. of pectin 75 65 55 45 35 25 gelation to exp. ° c 10 29.6 21.2 15 20 50 270 720 820 19 11 25.1 22.5 50 120 250 400 530 730 19 12 29.4 21.5 10 15 30 440 1300 170 12 13 27.3 22.9 10 20 70 600 900 0 15 14 29.7 21.0 150 170 450 570 650 840 24 710 It appears that from Table 15.1 the deesterified and amidated pectin fractions obtained - from the highly pectin fractions are termed, have a significantly lower 'hot viscosity' (70-80 ° C) and a narrower gelation temperature range compared with the similarly treated pectin product obtained from a pectin extracted in bulk from the same origin as the selected pectin fractions.

EXAMPLE 16 Basic deesterification in the presence of alkali metal ions 6 g of a first pectin fraction having a GE of 73.8, was subjected to amidation at a temperature of 20 ° C for 6.5 hours in a solution of 15.68 g of isopropanol, 16.91 g of water and 2.64 g of ammonia solution 25% The concentration of ammonia in the solution was 1.9% by weight. A pectin fraction was obtained that had a GE of 30.7 and a GA of 21.5.

In a second experiment, 6 g of the same pectin fraction was subjected to amidation at a temperature of 20 ° C for 6.5 hours in a solution of 15.68 g of isopropanol, 16.91 g of water, 2.64 g of 25% ammonia solution. and 1.00 g of sodium chloride. A pectin fraction was obtained that had a GE of 22.4 and a GA of 17.7.

Following the same procedure as the previous one, except that the sodium chloride was replaced with 1.276 g of potassium chloride, a pectin fraction was obtained that had a GE of 32.1 and a GA of 16.9.

EXAMPLE 17 Extraction of lime peel 250 g of dried lime husk having a dry matter content of 90.0%, was suspended in 4700 g of deionized water and the suspension was heated to a temperature of 70 ° C with gentle agitation. By the addition of concentrated nitric acid (10.1 g), the pH was adjusted to 2.5. The suspension was gently stirred for 2 hours at 70 ° C after which the liquid was separated from the extracted husk in a screen. The shell residue was washed twice with hot water (2 x 800 ml) and drained.

The residue of the wet shell of the first extraction was subjected to a second extraction by suspension in water (total weight of shell material + water: 4950 g) with 6.97 g of concentrated nitric acid added. The mixture was gently stirred for 2 hours at 70 ° C at pH 2.0. The residue of the shell was separated on a screen and washed twice with hot water (2 x 800 ml) and then drained again.

The residue of the wet shell of the second extraction was subjected to a third extraction by suspension in water (total weight of shell material + water: 4950 g) with 13.24 g of concentrated nitric acid added. The mixture was stirred gently for 2 hours at 70 ° C at pH 1.7. The extraction mixture was then separated on a screen and the shell residue was washed twice with hot water (2 x 800 ml).

The extract and wash water from the first extraction were combined and purified by centrifugation, followed by filtration through a vacuum filter covered by the filter device (Celite). The clear filtrate was stirred at room temperature with the Na * form of a strongly acidic cationic resin (Amberlite 2000C) for at least 4 hours. The cation exchange material was removed by filtration and the pH of the pectin filtrate was adjusted to 3-3.2 by the addition of ammonia.

The filtrate was concentrated by vacuum evaporation to a pectin concentration of approximately 1-2% and the pectin was precipitated by pouring the concentrated pectin solution into the double volume of isopropanol. (100%) The pectin was separated from the liquid by filtration on a nylon cloth, squeezed and washed on the filter with 60% (w / w) isopropanol / water solution (mixture). The pectin was dried overnight in an oven with air at a temperature of 40 ° C. The production was 35.5 g (Fraction 1).

The extracts and wash water of the second and third extraction respectively, were combined and the pectin (Fraction 2 and Fraction 3) was isolated in a similar manner.

The yields and analytical characteristics of the three pectin fractions are shown in the following Table 17.1.

TABLE 17.1 EXAMPLE 18 Preparation of yogurt to drink The pectin fractions of Example 17 above were tested in a drinking yoghurt system having the following composition: Yogurt base 258.8 g Sugar 44 g Water 244.4 g Pectin x g Dextrose 2.8 - x g For comparison purposes, a pectin extracted in bulk was used with the following characteristics: Degree of esterification (% 67.3% AUA: 85.1 US SAG °: 224 Adjustment time (sec): 155 Visc °: 75.8 The pectin extracted in bulk was prepared as described in the following: 157 g of lime peel having a dry matter content of 94.4% by weight, was suspended in 5500 g of deionized water and heated to a temperature of 70 ° C. By adding nitric acid (69%) the pH was adjusted to 1.7. After the liquid was separated from the material extracted from the shell in a screen, the liquid was drained on a nylon cloth filter covered with Celite 545. The resulting filtrate was treated overnight with an ion exchange resin (Amberlite 200 C ) and subsequently concentrated to approximately 1.5% pectin. The extracted pectin was precipitated by pouring the clear filtrate into two volumes of isopropanol with stirring. The precipitated pectin was separated by draining on a filter. After draining and pressing, the wet pectin was dried in an oven with air at a temperature of 40 ° C overnight. The dried pectin was ground to a fine powder. The production was 49 g.

The yoghurt base was made from recombined skim milk powder to a MSNF content of 17% and acidified with Glucono Delta Lactone (GDL) at a pH of 4.0.

Pectin and dextrose were added to the water with stirring. It was allowed to dissolve for approximately 20 min and then sugar was added. The yogurt base was stirred for 15 min and added to the pectin solution. The yogurt mixture was stirred for another 30 mm The yoghurt drinks were homogenized at 200 bar at room temperature and filled in plastic bottles. The yoghurt drinks were then heat treated for 10 min in a water bath at a temperature of 75 ° C. The bottles were shaken vigorously every 5 min. The samples were then cooled and kept overnight at 5 ° C.

The physical quality of a yogurt drink can be characterized by viscosity and sedimentation.

Frequently a low viscosity is preferred than a high viscosity of a yoghurt drink. The composition of the yogurt drink and the process by which it has been produced affects the viscosity, but the pectin and the dosage of the pectin used for stabilization will also affect the viscosity. With the addition of an insufficient amount of pectin, the beverage will not be stable and the viscosity will be higher if it is a MSNF beverage with a high solids content (8-9%) than that of a stabilized beverage. Also with the addition of excess pectin, the viscosity will be higher than that obtained with an optimum pectin concentration.

The viscosity was measured by means of a Brookfield Viscometer (model LVTDV-11) with non-shaft rods. 6.1 or 6.2 at 30 rpm. The yogurt drink (approximately 350 ml) was poured into a 400 ml glass beaker and warmed to a temperature of 10 ° C. Then the viscosity was read in centipoise (cP) after an equilibrium time of 30 seconds. The measurements were made after 1 day of storage.

The physical stability of the yoghurt drinks was evaluated by an accelerated test, exposing the beverages to a severe mechanical stress by centrifugation after 1 day of storage.

Approximately 40 g of the yoghurt drink was weighed in a 50 ml centrifugal glass. The sample was then centrifuged at 3500 rpm for 20 min. at room temperature. The supernatant was removed and the glass left up for 5 minutes before the remaining pellet was weighed.

The sediment was calculated and expressed in% weight based on duplicate determinations: % of sediment = weight of sediment x 100 / weight of the sample The results are shown in Table 18.1. The optimum pectin concentration is characterized by a minimum viscosity and a sedimentation of less than 2%.

TABLE 18.1 TABLE 18.1 (continued ' Fraction 2 is very appropriate for the stabilization of yogurt to drink. The pectin stabilizes the heat treated beverage at approximately 0.175% by weight of pectin. At this concentration the viscosity of the beverage is decreased to a minimum of 20.4 cP.

Fraction 1 is also suitable for the stabilization of drinking yoghurt, but a much larger amount (approximately 0.25%) of pectin is needed for stabilization.

EXAMPLE 19 Deesterification of selected pectin fractions 19. 1 Acid de-esterification of a first selected pectin fraction g of the first pectin fraction selected from Example 17 was deesterified (to pH 0.9) substantially as described in Example 7 except that the reaction was carried out for 6 hours to give 29.4 g of a de-esterified pectin. The analytical characteristics of the recovered pectin are shown in Table 19.1 below. 19. 2 Acid de-esterification of a second selected pectin fraction g of the second pectin fraction selected from Example 17 was deesterified (to pH 0.8) substantially as described in Example 7 except that the reaction was carried out at a temperature of 53 ° C for 5 hours to give 29.7 g of a deesterified pectin. The analytical characteristics of the recovered pectin are shown in Table 19.1 below.

TABLE 19.1 It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (39)

1. A method for obtaining selected pectin fractions having successively increased adjustment times, characterized in that the method comprises subjecting a highly esterified pectin-containing starter material to a first treatment cycle, comprising a step of extracting the initiator material with an aqueous medium at an acid pH under conditions where only part of the pectin content is extracted, separating the pectin extract from the treated starter material and recovering the pectin from the extract to obtain a first pectin fraction, followed by at least one additional treatment cycle, whereby the treated starter material extracted in the preceding cycle is treated to obtain a second and optionally one or more additional pectin fractions, the pH of the extraction medium in each of the second cycle and the additional one is lower than in the cycle of immediately preceding treatment.

2. A method according to claim 1, characterized in that the pectin-containing starter material is a pectin-containing material that has been pre-treated.

3. A method according to claim 1, characterized in that the pH of the aqueous medium is in the range of 1 to 4.

4. A method according to claim 1, characterized in that the pectin-containing starter material is derived from a natural plant material in a fresh and dry state.

5. A method according to claim 1, characterized in that the pectin-containing starter material is the solid extraction residue from the preceding extraction step.

6. A method according to claim 1, characterized in that the extraction is carried out at a temperature in the range of 40 ° C to 100 ° C for a period of time of 1 to 20 hours.

7. A method according to claim 1, characterized in that the extraction mixture has a dry matter content of the pectin-containing material that is in the range of 1% to 5% by weight, preferably in the range of 2% to 4% in weigh.

8. A method according to claim 1, characterized in that the aqueous solution contains a water-soluble calcium and / or aluminum salt added in an amount corresponding to a concentration of the metal ion in a range of 10 mmol to 40 mmol per liter of the extraction liquid.

9. A method according to claim 1, characterized in that the pectin is recovered from the extract by precipitation with an organic solvent miscible in water in which the pectin is substantially insoluble, separating the precipitated pectin from the liquid and drying the separated pectin.

10. A method according to claim 1, characterized in that the pectin is recovered from the extracts by adjusting the pH of the extract to a level in the range of 2 to 2.5, by adding a strongly acidic cation exchange resin in the salt form to raise the pH at a level in the range of 2.5 to 3.5, stir the mixture at room temperature for 4 to 8 hours, separate the liquid from the ion exchange resin, precipitate the pectin by adding a water-miscible organic solvent, separate the pectin precipitated from the liquid and dry the separated pectin.

11. A method according to claim 2, characterized in that the pre-treatment comprises heating a suspension of the pectin-containing material at a temperature of 60 ° C to 80 ° C in a substantially homogeneous solvent mixture comprising water and at least one solvent water-miscible organic in which the pectin is substantially insoluble to which an acid is added to maintain a fixed pH of the suspension within the range. from 1 to 3 during the treatment and separate the material containing pre-treated pectin.

12. A method according to claim 11, characterized in that the weight ratio between the solvent and water in the pre-treatment mixture is from 40:60 to 80:20, the amount of water is the sum of the water added and the water present in the material containing pectin before the heat treatment.

13. A method according to claim 11, characterized in that the pectin-containing material is treated with heat for a period of 2 to 6 hours, preferably 3 to 4 hours ..}.

14. A method according to claim 11, characterized in that the material containing pre-treated pectin is subjected to at least one washing step.

15. A method according to claim 11, characterized in that the pre-treated pectin-containing material is dried to obtain a content of dry matter in the material of at least 80% by weight.

16. A method according to claim 15, characterized in that the pre-treated pectin-containing material is dried at a temperature in the range of room temperature to 100 ° C for a period that is at most 36 hours.

17. A selected pectin fraction obtained by the method according to any of claims 1-16, characterized in that the fraction has a degree of esterification that is at least 50% and an adjustment time that is in the range of 0 to 100 sec. , 101 to 200 sec, 201 to 300 sec or in excess of 300 sec, in time of adjustment is determined by the method of Joseph and Bair (Food Technology, 1949, 18, 18-22) in terms of the time required to obtain the Complete gelling of a hot pectin-sugar-water standardized solution at pH 2.1 to 2.5 when cooled to a constant temperature of 30 ° C

18. The use of a pectin fraction according to claim 17, characterized in that the preparation of a food product is used.

19. The use according to claim 18, characterized in that the food product is an acidified milk product having a pH of 305 to 4.5.

20. The use according to claim 18, characterized in that the food product is preserved.

21. A method for stabilizing an acidified dairy product, characterized in that it comprises adding to a dairy product an amount of a pectin fraction as defined in claim 17, the addition of the fraction results in an improvement of the dairy product, the improvement is selected from the group consisting of at least 10% reduction in viscosity, at least 10% of the smallest particles and at least 10% less sediment, compared to the addition of the same amount of a pectin product extracted in bulk.

22. A method according to claim 21, characterized in that the improvement is selected from the group consisting of at least 2 times the viscosity reduction, at least 2 times smaller particles and at least 2 times less sediment, compared to the addition of the same amount of a pectin product extracted in bulk.

23. A method for obtaining a deesterified pectin fraction, characterized in that it comprises subjecting a selected pectin fraction obtained by the method of any of claims 1-16 and having a degree of esterification that is 50% or greater, to at least one stage of deesterification treatment, which comprises reacting the highly esterified pectin fraction with a deesterification agent to obtain a pectin fraction having a degree of esterification (GE) that is reduced by at least 5% relative to that of the fraction of highly esterified pectin and a degree of amidation (GA) that is in the range of 0-25%.

24. A method according to claim 23, characterized in that the desesified pectin fraction having a GE that is reduced by at least 5% relative to that of the highly esterified pectin fraction, is used as a starter material in a deesterification step additional.

25. A method according to claim 23, characterized in that the resulting deesterified pectin fraction has a GE that is at most 70% such as less than 60%, including less than 50% such as less than 45%.

26. A method according to claim 25, characterized in that the fraction of deesterified pectin has a GE that is in the range of 20-45.

27. A method according to claim 23, characterized in that the deesterification agent is selected from the group consisting of an acid and ammonia.

28. A method according to claim 27, characterized in that the deesterification comprises the thermal treatment of the selected pectin fraction in an aqueous solution or suspension in the presence of an acid to give a pH of at most 1.

29. A method according to claim 27, characterized in that the deesterification occurs in a reaction mixture having a dry matter content of pectin which is in the range of 1 to 5% by weight.

30. A method according to claim 27, characterized in that the deesterified pectin fraction is recovered from the reaction mixture by adjusting the pH of the mixture to a value in the range of 3 to 5 by the addition of a base, followed by precipitation of the de-esterified pectin fraction in an organic solvent miscible in water or in a homogeneous solution of an organic solvent miscible in water and water and separating the precipitated pectin fraction.

A method according to claim 23, characterized in that the fraction of deesterified pectin obtained has an amidation degree that is in the range of 5 to 25, including the range of 15 to 25.

32. A method according to claim 23, characterized in that the ratio between the degree of esterification and the degree of amidation in the resulting de-spiked pectin fraction is at least 0.75, such as in the range of 0.75 to 2.00 including the 1.0 range. to 1.5, for example in the range of 1.0 to 1.2.

33. A method according to claim 23, characterized in that the deesterification is carried out in a suspension of a highly esterified pectin fraction obtained by the method of any of claims 1-17, or of a desesified pectin fraction obtained by The method of any of claims 23-32 in an aqueous solution comprising an organic solvent miscible with water and ammonia.

34. A method according to claim 33, characterized in that the amount of pectin dry matter in the suspension is in the range of 10 to 30% by weight of the suspension.

35. A pectin fraction obtained by the method of any of claims 23-34, characterized in that the fraction has a degree of esterification that is less than 50% and a degree of amidation that is in the range of 0 to 25.

36. A pectin fraction according to claim 35, characterized in that it has a degree of esterification that is at most 45% including at most 40%.

37. A pectin fraction according to claim 35 or 36, characterized in that it has an amidation degree that is in the range of 5 to 25.

38. A pectin fraction according to claim 35, characterized in that the ratio between the degree of esterification and the degree of amidation in the resulting de-esterified pectin fraction is at least 0.75, such as in the range of 0.75 to 2.00 including the range from 1.0 to 1.5, for example in the range of 1.0 to 1.2.

39. The use of a pectin fraction according to any of claims 35-38, characterized in that it is used in the preparation of a food product.