General characteristics of the products of this group
The word "jelly" generally refers to the food jelly produced by the fruit and berry juice, pectin, gelatin and other gelling agents.
In the confectionery industry in the USSR "jelly" jelly marmalade called product type, in which the jelly structure due to the use of agar, pectin or agaroid. In these products is achieved imitation flavor, aroma and color natural fruits and berries by adding acid, essential oils, essences, dyes and vanillin. There is also the possibility of creating the taste and flavor, the addition of fruit juices or supplies. Fruit jelly on agar is transparent. When adding stores or puree it loses its transparency.
Depending on the preparation method, in particular by molding method, there are three main types of fruit jelly mass production.
- Shaped - in the form of products of various curved shapes, molded by casting in a hard form.
- Three-layer - as carvings rectangular or rhomboid shape with two outer layers and jelly core layer of whipped egg mass.
- Orange and lemon slices - in the form of semi-circular slices of orange and lemon.
Depending on the kind of gelling agents used to distinguish tin marmalade agar and pectin agaroid.
Agar its chemical composition and physico-chemical properties
In the production of jelly marmalade, a special role is played by agar. It is a vegetable glue, which is extracted from seaweed (Anfeltia, Helidium, etc.), growing near the coasts of the White Sea and the Pacific. The conditions for the agglomeration of the agar are somewhat different than for pectin. Studies of the chemical composition of agar indicate that, like pectin, it is a highly polymeric compound of the polysaccharide type having a chain-like molecule. As a result of the hydrolysis of the agar, up to 33% galactose is obtained to the weight of the initial agar. This indicates the presence in the last galactan. In the composition of agar, other reducing substances of carbohydrate character were also found.
The agar contains 3-5% of sulfur in the form of organically bound (not separated by dialysis) sulfuric acid. The latter is in the ester bond with the carbohydrate agar molecule complex.
Like Protopectin agar contains in its composition of calcium and magnesium. At their disposal is obtained agar acid.
These data led to the hypothesis that the native agar is a salt of an acid kaltsievomagnievuyu ether polysaccharide galactan - galactose - using the following exemplary scheme:
where R represents carbohydrate complex.
Based on the latest data it can be assumed that the demineralized agar is a linear polysaccharide sulfuric ether
Agar chain is composed of residues 9 d-galactose, linked glucoside bond (positions in 1 and 3, and has a terminal residue of l-galactose, which has six atoms esterified with sulfuric acid.
In some cases, acetyl groups were detected in the composition of the agar while most researchers found no agar in its composition of methoxyl groups, so characteristic of pectin.
In addition to the most important components in the purified agar contains from up to 1 3% of nitrogenous substances.
Agar pure almost insoluble in cold water (10- 15 °), but it swells in it as colloid limited swelling. In hot water by boiling the agar dissolves almost completely (in solution passes to agar 99% depending on degree of purity).
From aqueous solutions (sols) agar as pectin is precipitated with alcohol and electrolytes.
When cooling hot aqueous agar solution becomes jelly (gel).
The latter is obtained at a concentration of agar since 0,2% by (weight jelly. The aqueous solution containing 0,3-1% agar jelly form durable vitreous fracture.
The main provisions on the mechanism of pectin formation are applicable to agar. However, for the agglomeration of agar, in contrast to pectin, the presence of sugar and acid is not required. The presence of sugar or other dehydrating substance is not necessarily also in the formation of gelatin jelly. Attempts to explain this phenomenon boil down to the fact that agar or gelatin particles have a stronger ability for hydration (solvation) than pectin particles. The amount of free water that is contained in the surrounding ash is not sufficient to completely hydrate the agar particles, so the value of sugar as a dehydrating agent in this case disappears.
Upon heating agar in acidic conditions, is its hydrolysis, in which it loses its studneobrazuyuschie properties. At neutral pH conditions agar makes higher temperatures.
Degradation studneobrazuyuschey agar capacity in an acidic medium develops rapidly when heated, since 60-70 ° temperature. Agar is much less resistant against acid action compared to pectin. With respect to the alkali agar, in contrast, has a higher resistance than the pectin.
The ratio of agar to metal cations other than pectin. Thus, for example, it found that alkali metal ions and in particular K + ion reinforce strength agar gels to a much greater extent than the Ca ++ ion. Generally, in contrast to pectin alkalinization increases the strength of agar gels. This is because, while neutralizing acidity agar its resistance increases during heating.
Studneobrazuyuschaya ability of agar as well as pectin depends on its degree of polymerization of the molecule. According to reports  the molecular weight of the soluble fraction of agar ranges 11 000-25 000.
Gelling point 1% solution of agar jelly containing 60-70% of sugar, lies close to 40 °. Thus, the jelly mass prepared from 1% solution of agar gelled at lower temperatures than the corresponding sugar-pectin solutions. In connection with this process of gelation (SADC), fruit jelly (agar) requires a longer time than the process ponds, fruit and berry marmalade.
Agar normally supplied to the mill in the form of thin films, bars or grits containing up 18-20% (water. Of particular importance when using agar in the confectionery industry has studneobrazuyuschaya its capacity and the degree of purification, in particular the absence of extraneous (taste and smell.
Black Sea agar (agaroid) and its properties
Along with the agar in the confectionery industry is also used other gelling agents derived from algae of the genus "filofora" growing in the northwestern part of the Black Sea. This product has the physico-chemical properties are slightly different from agar. In this regard, it is regarded as substance agaropodobnoe - agaroid. In some respects it approaches the pectin.
The chemical composition and structure agaroid still insufficiently investigated. According to some reports, as part of agaroid contain galactose, glucose and fructose, sulfur, Na, Ca, Mg, a small amount of acetyl groups.
Similarly agar it is poorly soluble in cold water, soluble in hot water.
The aqueous solutions (sols) for cooling agaroid jellies form (gels) starting 0,8-1,0% concentration.
In terms of production capacity for confectionery studneobrazovaniyu agaroid 3-3,5 in times less than that of agar and 2-2,5 times lower than the pectin. For agaroid-aqueous sugar-jelly (with 70% concentration of sugar) it is necessary to spend about 3% of air-agaroid to the weight of the finished jelly.
The introduction of alkali metal ions has a positive effect on the ability studneobrazuyuschuyu agaroid. In this respect it differs from close to pectin and agar.
Agaroid is similar to high temperature by pectin and agar gelling by its high sensitivity to acid. In an acidic medium at a temperature above 70-75 ° it undergoes rapid hydrolytic decomposition and loses its ability to studneobrazovaniyu. Agaroid destruction increases with increasing temperature and increasing duration of its interaction with the acid.
The melting point of the water jelly (3% agaroid) lies within 60-65 °. Low gelling solutions agaroid 70% sugar in the presence of acid to close 70 °.
These properties agaroid limit its use in the manufacture of confectionery products, which require some time for casting jelly mass to its gelling and where you must enter the acid mass to the molding of the latter, ie. E. Until gelling it.
VKNII Studies have shown that some protection against acid cleavage agaroid can be obtained by introducing the salt of an alkali or buffer character. It has been found that very effective in this regard is the Na salt2NR04.
Depending on the amount of salt administered occurs more or less offset marmalade pH to the alkaline side, ie. E. Alkalization latter. Therefore salt dosage should not exceed 0,1% by weight of marmalade mass; higher salt dosage cause a sharp weakening of the organoleptically perceived acid in the taste of marmalade.
Aqueous solutions are highly viscous agaroid.
Hydrophilic properties, in particular the ability to retain water at agaroid less pronounced than that of agar and pectin, as a consequence of its resistance against drying jellies saccharification and lower than that of agar and pectin jellies.
Recipe želejnogo jam
Recipe for different varieties of fruit jelly is made up of the following exemplary relations major components (in% by weight of finished product): agar 0,8-1 (or pectin 1,0-1,5, agaroid 2,5-3), sugar 50-65, molasses 20-25, acid (citric or tartaric) 1 -1,5.
Sugar, in addition to its flavoring value, plays here the role of a solid filler, which replaces water in jelly. Molasses in this case, as in fruit and berry marmalade, is used as a thickener and as a means of delaying the crystallization of sugar. The participation of molasses in the formulation of jelly marmalade from agar and agaroid is very important, since there are no other reducing sugars other than glucose and maltose molasses in the other components of its formulation. Acid in the marmalade from agar and agaroid plays the role of a flavoring agent.