US2533471A

US2533471A - Pectin jelly compositions

Info

Publication number: US2533471A
Application number: US655368A
Authority: US
Inventors: Charles W Kaufman
Original assignee: General Foods Corp
Current assignee: General Foods Corp
Priority date: 1946-03-18
Filing date: 1946-03-18
Publication date: 1950-12-12
Anticipated expiration: 1967-12-12

Description

Patented Dec. .512, lgfiii pitgrail PECTIN JELLY COMPOSITIONS Charles W. Kaufman, Tenafly, N. J assignor to General Foods Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application March 18, 1946, Serial No. 655,368

- Claims.

This invention relates to pectin jelly compositions and more particularly to such compositions of the low-sugar type in which the jellies contain little or no sugar.

For a long time it was believed that pectin jellies could not be made without a relatively large amount of sugar, the minimum content of soluble solids (mostly sugar) being variously placed between 40% and 50% and the usual fruit jelly containing 60-65%. However, it has been found comparatively recently that pectin which has equivalent or combining weight determined by standard methods. Pectins useful for making high-sugar fruit jellies of the first mentioned type are high-equivalent-weight pectins having an equivalent weight of at least 400 and ranging upward to about 1000. On the other hand, pectins useful for making low-sugar jellies are lowequivalent-weight pectins having an equivalent weight of from 250 to 350.

It should be understood that while the pectins may be in a partial state of neutralization for better keeping qualities, the stated equivalent weight values are the equivalent weights of the free acids. Also pectins prepared by methods such as alcohol precipitation, for example, often include substantial amounts of precipitated organic non-pectinous material. This so-called ballast material may cause the apparent equivalent weight of the sample to be as much as -25% higher than the true equivalent weight of the pectin when properly purified, as for example by precipitation from solution by metal ions. In such cases the stated equivalent weight values are the true equivalent weights of the pure pectinic acid fractions.

it has been observed that such low-sugar pectin jellies are much more susceptible to syneresis or weeping than high-sugar jellies. Syneresis can best be described as a shrinkage of the gel structure with consequent separation of part of the water and its appearance on the surface of the gel. All pectin jellies are susceptible to syn-- eresis to some extent, but high-sugar pectin jellies do not exhibit syneresis to any great degree if properly prepared. With low-sugar jellies, on the other hand, the usual precautions are insufficient to reduce syneresis to an extent where it is no longer detectable or objectionable, which is especially true if little or no sugar is used in the jellies.

The object of the present invention is to minimize syneresis in low-sugar pectin jellies and particularly in such jellies which are canned or otherwise sealed for shipment or storage for relatively long periods of time.

I have discovered that the syneresis which develops in low-sugar pectin jellies may be materially reduced by using, in addition to the lowequivalent-weight pectin which forms the jelly, a certain amount of high-equivalent-weight pectin. At the low sugar concentrations contemplated, the latter pectin appears not to participate appreciably in the bonding or other action involved in the formation of the jellies, but does have a definite and important effect in minimizing or preventing syneresis. Such relatively inert pectin may be employed with substantially equal effectiveness whether the low-equivalentweight pectin is caused to gel by the presence of alkaline-earth ions or of other metallic ions such as aluminum, irons, manganese or nickel. I prefer, however, to employ edible calcium or magnesium salts for the purpose of jellification. Also any high-equivalent-weight pectin can be used, but I prefer to use pectins having equivalent weights between 400 and 600 because of their greater viscosity. The high and low-equivalentweight pectins may be obtained from any of the usual sources, for example, citrus peel and apple pomace.

It is known that the demethoxylation of pectin yields pectinic acids of different degrees of demethoxylation rather than a single pectinic acid. In a given specimen of demethoxylated pectin, these different pectinic acids are very difficult to separate. Their presence can be determined by hydrolysis.

cataphoretic analysis using for example the socalled Tiselius apparatus, but the equivalent weight of such a specimen, when determined in the usual manner, is a definite value representing an average of the different pectinic acids present. It is proper to regard such a specimen as pectinic acid identifiable by its measured equivalent weight, and the values of 250 to 350 for low-equivalent-weight pectin, as well as the minimum value of 400 for high-equivalent-weight pectin, relate to such measured equivalent weights. Nevertheless a low-equivalent-weight pectin having a measured equivalent weight be tween 250 and 350 may actually comprise pectinic acids having equivalent weights ranging from less than 250 to more than the minimum value of 400 specified for high-equivalent-weight pectin.

The spread of pectinic acids in any pectin depends on the kind of hydrolysis by which it was demothoxylated, e. g., hydrolysis by acid, hydrolysis by alkali, or enzymatic hydrolysis under conditions of slight acidity. This spread is least in pectin demothoxylated by acid hydrolysis and greatest in pectin demethoxylated by enzymatic It has been observed that low-sugar jellies made with low-equivalent-weight pectin produced by alkali and enzymatic hydrolysis exhibit less tendency toward syneresis than aciddemethoxylated pectins. This now appears to be due to the greater spread of pectinic acids in the former types of pectin, i. e., to an appreciable proportion of high-equivalent-weight pectinic acid, and also to the fact that the jellying power of such pectins is low so that they must be used in larger amounts to effect jellification than acid-hydroylzed pectin. Hence a smaller amount of added high-equivalent-weight pectin is required for syneresis reduction, and the ratio of added high-equivalent-weight pectin to lowequivalent-weight pectin is less, than in the case of acid-hydroylzed pectin, but the actual amounts of high-equivalent-weight pectinic acid are comparable. I prefer to use acid-hydrolyzed low-equivalent-weight pectin for jellification and to admix it with the proper proportion of high-equivalent-weight pectin for syneresis reduction.

Similarly, once separately demethoxylated pectins of low-equivalent-weight and high-equivalent-weight has been admixed, they can not be separated by ordinary equivalent weight determinations because the mixture will have a single definite equivalent weight value. For example, a mixture of 300 equivalent weight pectin and 600 equivalent weight pectin would have an intermediate equivalent weight when determined by standard methods, the value of which would depend on the relative proportions of the pectins. However, the presence of the two pectins as components of the mixture can readily be determined by other methods such as electrophoretic analysis in the Tiselius apparatus (for a description of this apparatus and its operation see The electrophoretic study of proteins and related substances by Duncan A. MacInnes and Lewis G. Longsworth, Alexander's Colloid Chemistry, vol. 5, Reinhold Publishing Corporation, 1944, pgs. 387-411, inclusive).

The reduction in syneresis is proportional to the concentration of high-equivalent-weight pectin employed in making the jellies, but excessive quantities of such relatively inert pectin may adversely affect the texture and quality of the jellies. The optimum amount of high-equiv- Ill) 4 alent-weight pectin is that which will effectively minimize syneresis without unduly affecting the character of the jellies, but this optimum amount depends on several factors and may vary widely under different conditions as explained hereinafter.

By way of illustration, when using low-equivalent-weight pectin obtained by acid hydrolysis and high-equivalent-weight pectin of comparatively high grade, the high-equivalent-weight pectin is best employed in the proportion of 10 to 20% of the low-equivalent-weight pectin, provided the proportion of sugars and other dissolved solids is about 20 to 40%, as in the case of jellied fruit salads. On the other hand, in the case of aspic, madrilenes, consommes and other compositions containing a relatively low proportion of dissolved solids, say 5 to 15%, the optimum proportion of high-equivalent-weight pectin appears to be of the order of 20 to 30% of the low-equivalent-weight pectin. It is to be understood, however, that the invention is in no way limited to these specified proportions of high-equivalent-weight pectin inasmuch as smaller or greater proportions may be optimum under other conditions. Also, it may be desirable to increase the extent of the reduction in syneresis by increasing the proportion of highequivalent-weight pectin above the optimum, though in general it should not exceed the proportion of low-equivalefit-weight pectin.

The amount of high-equivalent-weight pectin to be used in a given low-sugar pectin jelly product is also dependent on the grade of the pectin in the same manner as if it were used in the preparation of a high-sugar jelly For example, 300 grade pectin is about twice as viscous as and can thus be used in approximately half the amount of grade pectin.

Suspended solids such as those present in jellied fruit and vegetable salads have been found to be without effect on syneresis and, hence, on the amount of high-equivalent-weight pectin required to minimize syneresis. On the other hand, the presence of dextrins and sugars in solution has been found to have a very pronounced effect on the required amount of high-equivalent-weight pectin, which is reduced in proportion to the concentration of such solubles. The amount of high-equivalent-weight pectin may be similarly affected by other dissolved solids which are apt to be contained in jellied products.

I have also found that low-sugar jellies exhibit maximum syneresis at certain pH values depending on the amount of metal ion employed for jelllfication. In a series of tests on tomato aspic, for example, it was found that when the amount of calcium was 1.77 times the amount theoretically necessary to fully combine with the jellifying pectin, maximum syneresis occurred at a pH of 4.1. In another series, in which the amount of calcium was 0.75 times the theoretical amount, maximum syneresis occurred at a pH of 3.4. If possible, low-sugar jellies should be so prepared as to avoid conditions leading to maximum syneresis, thereby permitting economy to be effected in the amount of high-equivalent-weight pectin employed for syneresis reduction.

Buffer salts, such as the alkaline citrates, phosphates, acetates, etc., do not of themselves affect the amount of high-equivalent-weight pectin, but do so indirectly because of their effect on pH.

The benefits which may be derived from the invention are illustrated by the following examples, in which tomato aspic was prepared with and without the addition of high-equivalent- Each jelly contained 1.77 times the theoretical amount of calcium and was measured to have a pH of 4.1 so that its tendency toward syneresis was maximum, thereby permitting a more precise evaluation of the different degrees of syneresis.

In preparing the jellies, the tomato juice, spice, citric acid, and pectins were mixed, and the mixtures brought to a boil. The calcium phosphate, dispersed in 5 cc. of water, was then added and, after a few hours, the jellies set. The purpose of adding the calcium phosphate in the form of a dispersion in water was to prevent discontinuous particles of calcium pectinate from forming in the jellies.

The jellies were sliced to promote syneresis and, in this form, allowed to stand for five hours in a covered Buchner funnel in which the air was maintained saturated with humidity to prevent drying of the jellies. The respective amounts of exudate were determined by loss in weight of the jellies and were 5.4% in the case of the control jelly and 3.3% in the case of the improved jelly, a reduction of 40%. The degree of syneresis in the control jelly is considered excessive, whereas that in the improved jelly is regarded as being moderate and readily tolerated in commercial production. A greater reduction would have been obtained by increasing the proportion of high-equivalent-weight pectin, but considerations of cost and effect on the finished jelly, as well as the acceptability of the 40% reduction in syneresis, made it desirable to limit the amount or high-equivalent-weight pectin used.

The following examples illustrate the progressive reduction in syneresis accomplished by increasing amounts of high-equivalent-weight pectin. Four jellies were prepared each of which contained the following ingredients:

Grams Tomato juice 500 Salt 3.75 Citric acid 1.05 Tricalcium phosphate 1.50 310 equivalent weight pectin (acid demethoxylated) 3.10

In addition, the four jellies contained the following amounts of 400 equivalent weight pectin Jelly 4i 2.90

The jellies were cut into small cylinders of about inch in height and inch diameter.

These cylinders were placed upright on blotting paper and allowed to stand for three hours on such paper in covered Petri dishes. The comparatively small spaces in which the cylinders were confined resulted in negligible evaporation of moisture. The difierences between total areas of stain and cylinder area were taken as a measure of the relative amounts of exudate absorbed by the blotting paper. The following table gives the net areas in square inches and the jelly strengths of the four jellies as measured by the Bloom gelometer:

Jelly strength Net Area rnanufacturer. It will be understood that the rpression jelly composition as used in the claims is intended to cover such dry mixtures, which can be used to prepare jellies by adding the necessary fruits, vegetables, tomato juice,v

soup stock, etc., as well as the finished jellies which are prepared by the housewife or which are sold to her in cans or other containers.

It will be further understood that the expression low-sugar, when used to qualify such jelly compositions, is meant to designate compositions in which gelation occurs by virtue of the interaction of metal ions with pectin of a low degree of esterification, and in which sugar plays substantially no role in contrast to the usual jellies wherein certain minimum concentrations of sugar are required for gelatin.

What is claimed is:

l. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients, the jelliflcation ingredient consisting of low-equivalent-weight pectin capable of forming a jelly of less than 30% soluble solids, the other pectinous ingredient consisting of a smaller amount of high-equivalent-weight pectin that does not jellify with less than 30% soluble solids, said other ingredients reducing syneresis in the finished jelly.

2. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients, the jellification ingredient consisting of pectin having an equivalent weight between 250 and 350, the other pectinous ingredient consisting of a smaller amount of pectin having an equivalent weight above 400 for reducing syneresis in the finished jelly.

3. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients, the jellification ingredient consisting of pectin having an equivalent weight between 250 and 350, the other pectinous ingredient consisting of a smaller amount of pectin having an equivalent weight between 400 and 600 for reducing syneresis in the finished jelly.

i. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients and an edible salt of a metal of the group consisting of calcium and magnesium, the jellification ingredient consisting of low-equiva-= 7. lent-weight pectin capable of forming a. jelly of less than 30% soluble solids, the other pectinous ingredient consisting of a smaller amount of high-equivalent-weight pectin that does not jelliiy with less than 30% soluble solids, said other ingredient reducing syneresis in the finished jelly.

5. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients and an edible salt of a metal or the group consisting of calcium and magnesium, the jelliflcation ingredient consisting of pectin having an equivalent weight between 250 and 350, the other pectinous ingredient consisting of a smaller amount of pectin having an equilavent weight above 400 for reducing syneresis in the finished jelly.

6. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients and an edible salt of a metal of the group consisting of calcium and magnesium, the jellification ingredient consisting of pectin having an equivalent weight between 250 and 350, the other pectinous ingredient consisting of a smaller amount of pectin having an equivalent weight between 400 and 600 for reducing syneresis in the finished jelly.

'7. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients, the jellification ingredient consisting of low-equivalent-weight pectin capable of forming a jelly of less than 30% soluble solids, the other pectinous ingredient consist'ng of highequivalent-weight pectin that does not jellify with less than 30% soluble solids in the proportion of -20% by weight of the jellification ingredient.

8. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous in- 8 gredients, the jellification ingredient consisting of pectin having an equivalent weight between 250 and 350, the other pectinous ingredient consisting of pectin having an equivalent weight above 400 in the proportion of 520% by weight of the jellification ingredient.

9. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients and an edible salt of a metal of the group consisting of calcium and magnesium, the jellification ingredient consisting of pectin having an equivalent weight between 250 and 350, the other pectinous ingredient consisting of pectin having an equivalent weight above 400 in the proportion of 23-20% by weight of the jellification ingredient.

10. A pectin jelly composition of the low-sugar type comprising a mixture of two pectinous ingredients and an edible salt of a metal of the group consisting of calcium and magnesium, the jellification ingredient consisting of pectin having an equivalent weight between 250 and 350, the other pectinous ingredient consisting of Dectin having an equivalent weight between 400 and 600 in the proportion of 5-20%. by weight of the jellification ingredient.

CHARLES W. KAUFMAN.

- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,997,615 Wallerstein et al. Apr. 16, 1935 2,334,281 Olsen et al Nov. 16, 1943 2,358,430 Willaman et a1 Sept. 19, 1944 2,369,846 Olsen et al Feb. 20, 1945

Claims

1. A PECTIN JELLY CORPORATION OF THE LOW-SUGAR TYPE COMPRISING AMIXTURE OF TWO PECTINOUS INGREDIENTS, HE JELLIFICATION INGREDIENT CONSISTING OF LOW-EQUIVALENT-WEIGHT PECTIN CAPABLE OF FORMING A JELLY OF LESS THAN 30% SOLUBLE SOLIDS, THE OTHER PECTINUOUS INGREDIENT CONSISTING OF A SMALLER AMOUNT OF HIGH-EQUIVALENT-WEIGHT PECTIN THAT DOES NOT JELIFY WITH LESDS THAN 30% SOLUBLE SOLIDS, SAID OTHER INGREDIENTS REDUCING SYNERESIS IN THE FINISHED JELLY