Acids are added in the manufacture of certain confectionery products to give them a taste of the inherent fruit and berries.
For this purpose, apply tartaric (tartaric), citric, lactic and malic acid. All of these acids, except lactic, are crystalline.
Commercial lactic acid is a solution with a concentration of lactic acid 40 — 70%.
The crystalline acids used in the confectionery industry are interchangeable; lactic acid use is limited. It is used in such products, where the introduction of moisture into the product together with the acid does not impair its quality and does not complicate the technological process, for example, for acidification of fruit masses in candy production, marmalade and fruit caramel fillings.
The sensation of sour taste is explained by the presence of hydrogen ions. However, when determining the interchangeability coefficients of various acids, one cannot proceed only from the degree of their dissociation. It is established that the weaker the acid, the lower the concentration of hydrogen ions, at which the sour taste begins to be felt (sensation threshold).
In tab. 87 shows the sensation threshold values (according to Pisarev) and the acid dissociation constants used in the confectionery industry.
87 Table. Threshold and feelings acid dissociation constant
|acids||The dissociation constant||threshold of feeling|
|pH||molar concentration of acid MMOL in 1 l||amount of acid in grams in 100 ml solution|
|Dairy||1,37 * 10-4||3,45||2.7||0,0245|
|Wine||1,04 * 10-3||3,35||1.2||0,0160|
|Lemon||8,4 * 10-4||3,32||0,93||0,0178|
|apple||3,9 * 10-4||3,19||4,3||0,0576|
|Phosphorous||7,9 * 10-3||2,89||1.6||0,0157|
The relative concentration of acids, which determine the threshold of sensation, can shift in confectionery with a more intense taste and in the presence of substances that mask the sour taste. Therefore, for acidification of certain confectionery products with various acids, the dosage should be established practically.
We give the dosage of acids (according to Pisarev) in caramel, giving an identical taste (Table 88).
88 Table. Dosage caramel acids
|acids||Identical solutions of acids in grams of acid per 100 ml of solution||Caramel identical in taste when acidified with various acids in% acid by weight of caramel|
The inverting capacity of acids is different, which should be considered when acidifying confectionery and especially caramel mass. For an approximate assessment of the inventive ability of acids in the table. 89 gives the inversion coefficients of various Ostwald acids. The numbers in this table represent the relative magnitudes of the inversion rate constants, and the value for hydrochloric acid is taken as hundred.
89 table. The inversion coefficient of various acids according to Ostwald
For the preparation of invert syrup, replacing starch syrup, as the catalyst used hydrochloric acid, followed by neutralization.
For this, chemically pure or technical hydrochloric acid obtained electrolytically (GOST 857-41) should be used.
Technical acid should contain:
a) at least hydrochloric acid 31%;
b) iron no more than 0,01%;
c) not more than arsenic 0,0002%;
g) of sulfuric acid in terms of SO4 not more 0,005%.
Wine (tartaric acid) (C4Н6О6) - dibasic dioxyacid. Commodity tartaric acid is a programe isomer. It crystallizes in the form of colorless transparent prisms of the monoclinic system. It does not smell, the taste is pronounced sour. Specific weight 1,7598, molecular weight 150,09. The aqueous solution rotates the plane of polarization to the right. For 20% solution, angle of rotation αD20- 12 °.
Melting point of tartaric acid 170 °. The molten acid, when frozen, becomes an amorphous modification. When heated above 170 °, two molecules of the right tartaric acid, splitting off the water molecule, go into a double-vinous, which is a resinous mass.
Boiling point at 1 atm 25% solution of tartaric acid 102,2 °, for 50% - 106,7 °.
Tartaric acid is very soluble in water. Its solubility increases with increasing temperature (Table 90). In alcohol, it dissolves, but worse. In the air is practically insoluble.
90 Table. The solubility of tartaric acid based on temperature
|Temperature in ° C||Content of tartaric acid in% to solution||Temperature in ° C||Content of tartaric acid in% to solution||Temperature in ° C||Content in% tartaric acid to a solution of|
The dependence of the specific weight of aqueous solutions of tartaric acid on the concentration is given in table. 91.
91 Table. Dependence of specific weight aqueous solution of tartaric acid concentration
|The proportion of the solution||The amount of tartaric acid in g / l||The proportion of the solution||The amount of tartaric acid in g / l||The proportion of the solution||The amount of tartaric acid in g / l|
In tab. 92 is the refractive index of pure tartaric acid solutions.
92 table. The refractive index of pure tartaric acid solutions of various concentrations at 20 °
|The amount of tartaric acid in 100 ml solution in g||
|The amount of tartaric acid in 100 ml solution in g||
Technical specifications for tartaric acid. According to the standard
tartaric acid must meet the following requirements.
- Appearance - colorless or with a faint yellowish tint, large or small crystals and powder.
- Upon dissolution of the acid in distilled water should yield a clear solution containing no solids and odorless.
- Tartaric acid content on dry substance at least 99%.
- Foreign matter:
a) an ash content of not more than 0,5%;
b) the heavy metal content of not more than 0,0005%, including no more than arsenic 0,00014%;
c) the content of free sulfuric acid is not more 0,05%;
d) hydrochloric acid content of not more 0,02%;
d) lead salts are not allowed.
Storage conditions. Well dried tartaric acid should be stored in a dry place. Wet tartaric acid and its solutions are rapidly destroyed by the action of various microorganisms.
Citric acid (C6H8O7) - tribasic hydroxy acid, crystallizes from aqueous solutions with one water molecule in the form of colorless transparent rhombic prisms. It is odorless, the taste is clearly sour. The specific weight of anhydrous acid is 1,54, the molecular weight of 192,12, the molecular weight of aqueous acid is 210,14.
The melting point of aqueous citric acid is 70 — 75 °, anhydrous — 153 °. At 100 °, the aqueous acid completely loses the water of crystallization. Upon recrystallization, the dehydrated citric acid is obtained again in an anhydrous form. When heated to 175 °, one molecule of water is separated from the citric acid molecule, and the acid is converted to unsaturated occitate.
Citric acid is readily soluble in water, its solubility increases with increasing temperature (Table 93). Citric acid is soluble in alcohol; in 100 parts of 80% alcohol, with 15 °, 87 parts of aqueous citric acid are dissolved; in the 100 parts of absolute alcohol, the 43 parts of anhydrous acid dissolve.
93 Table. Citric acid solubility versus temperature
|Temperature in ° C||The content of citric acid in H to solution||Temperature in ° C||Content of citric acid in% to solution||Temperature in ° C||Content of citric acid in% to solution|
The dependence of the specific weight of aqueous solutions of citric acid concentration is given in table. 94.
Specifications for citric acid. According to the standard (GOST 908-41) citric acid should meet the following requirements.
Depending on the method of crystallization, edible citric acid is produced:
a) small crystals;
b) in the large crystals.
Food citric acid should be a colorless or slightly yellowish crystals; weak solutions (1 — 2%) of a pleasant sour taste.
When the acid is dissolved in distilled water, a clear, odorless solution should be obtained.
The dependence of the specific gravity of aqueous solutions of citric acid concentration
|Specific weight at 15 ° C||Amount of citric acid in g / l||Specific weight at 15 ° C||Amount of citric acid in g / l||Specific weight at 15 ° C||Amount of citric acid in g / l|
The content of citric acid must be at least 99% in the sample taken in terms of citric acid with one molecule of water of crystallization (C6Н807) • H2О.
a) ash no more than 0,5%;
b) sulfuric acid (free) Not more than 0,05%;
c) not more than arsenic 0,00014%;
d) should not contain alkaloids and ions: heavy metals, ferric syncytosis, barium and oxalic acid.
Storage conditions. Citric acid should be stored in
dry room. During transportation, it must be protected from moisture.
Malic acid (C3H6O5) or hydroxy-succinate — dibasic hydroxy acid, derived from vegetable raw materials (shag), is a levorotatory isomer. It crystallizes as needles with a melting point of 100 °. Well soluble in water.
Synthetic malic acid is a racemic compound of the right and left malic acids. It crystallizes easier levogyrate, less soluble in water, melts at a higher temperature (130 — 131 °). Molecular Weight of 134,09; the proportion of levorotatory 1,595, racemic 1,601. Left rotatory decomposes when heated above 140 °, and racemic over 150 °. The solubility of racemic modification in water at 26 ° is 144 by weight in 100 by weight parts of solvent, and at 79 ° by 411. It is easily dissolved in alcohol and ether.
Specifications for malic acid is the same as in the citric.
Lactic acid (C3Н603) - monobasic hydroxy acid. There are two types of lactic acid: α-hydroxypropionic or
ethylidene-lactic acid (CH3CHOHL) and β-hydroxypropionic or ethylidene-lactic acid (CH2ONSN2COOH). Of industrial importance is ethylidene-lactic acid, which is obtained by lactic acid fermentation in the form of a racemic mixture. Molecular weight of lactic acid 90,08.
In crystalline form, lactic acid can be obtained by careful evaporation of an aqueous solution of lactic acid under high vacuum. At atmospheric pressure, the crystals melt to form a colorless, syrup-like liquid of specific gravity 1,21, odorless and with a sharply sour taste.
Lactic acid is an unstable chemical compound. Depending on the conditions of production and storage, it easily forms dehydration products, usually combined under the general name of lactic anhydrides.
All products of dehydration, with the exception of dimolic acid, are compounds less valuable in taste than free lactic acid, since its acidic properties are due to the free carboxyl group.
When lactic acid is heated to 90 °, mainly lactyl-lactic acid is formed, to 100 — 110 ° in significant amounts of di-, tri-, tetra- and pentalactyl-milk acids, and when heated in vacuum to 180 — 250 ° - lactide.
The aqueous solution of lactic acid is an equilibrium system
The composition of the mixture depends on the concentration of lactic acid: the higher it is, the more it anhydrides.
Lactic acid and its anhydrides dissolve in water, alcohol and ether in all respects. The proportion of chemically pure lactic acid at 18 ° 50% - 1,16; 90% 1,21.
Lactic acid is supplied to confectioneries in the form of aqueous solutions with an acid concentration of 40 — 70% and in the form of a paste, in which about 10% of acids is bound to crystalline calcium lactate, which mechanically binds lactic acid to a solid paste.
Specifications for lactic acid. According to the standard (GOST 490-41) lactic acid in quality, regardless of the concentration of acid is divided into the I, II and III grades.
The acid must meet the following requirements.
To be transparent, without turbidity of sediment (it is allowed for acid II and III grade the presence of opalescence or sediment, disappearing when diluted with distilled water 1: 1).
a) acid grade I should be colorless or slightly yellow;
b) grade II acid may be from yellow to yellow brown;
c) acid grade III can have color from yellow to dark brown.
Smell and taste:
a) acid should not have a sharp unpleasant odor due to the presence of impurities in it of volatile acids;
b) in the 1% aqueous solution, the acid should have a clear, sour taste with no foreign flavor.
a) depending on the concentration and type of acid is characterized by indicators that are given in table. 95.
% acid, at least
|Pryamone- titratable lactic acid in%, not more||Ash% in not more than||% Nitrogen, not more than||Chromaticity, max|
|at a concentration in%|
Note. The color is determined by comparing the color of lactic acid with the color of the solution obtained by mixing 0,1 N solution of iodine and distilled water in the ratios indicated in table. 95;
b) by reacting the free sulfuric acid that metilviole- lactic acid solution does not appear green shade;
c) iron in terms of Re203 and 100% lactic acid should be no more than 0,05%;
d) lactic acid should not contain hydrocyanic acid, arsenic, salts of heavy metals (lead, copper) and salts of ferric and synosilicic acid.
Zhuravsky GI, Novoselov, LV, Eliseev MI, Vulihmai AA, Zakharova G., Manufacture of food acids, Pishchepromizdat, 1953.
Citric acid GOST 908-41.
Lactic acid food GOST 490-41.
Pisarev N. S., Acids and problems of inversion, hygroscopicity and color in caramel production, VNITO Confectioners' Edition, 1938.
Reference chemist, vol. I, Goskhimizdat, 1951.
Chichibabin the AE, Organic chemistry, Gostekhizdat, 1953.
Landolt-Börnstein, Zahlenwerte und Functionen aus Physik, Chemie, Astronomie Geophysik und Technik, Berlin, 1952.
The aroma of confectionery products reported natural flavoring and synthetic substances. With the introduction of aromatic substances products reported a certain taste.
Natural aromatic and flavoring substances include cocoa beans (grated cocoa, chocolate, cocoa powder), roasted coffee, nuts, vanilla, fruit and berry supplies and wines. Essential oils isolated from various ethereal plants of plant origin are also natural aromatic substances.
Synthetic fragrances include fragrances obtained by organic chemistry from semi-finished products of plant origin and fully synthetic products.
Some flavors can be classified as a natural or synthetic, depending on the method of their preparation.
Food aromatic essences are called aromatizers, which are alcoholic, aqueous-alcoholic, or acetyne solutions of mixtures of natural and synthetic aromatic substances. They are prepared according to the recipes approved by the Ministry of Food Industry of Ukraine in coordination with the State Sanitary Inspectorate of Ukraine.
Essences for the confectionery industry are available in single, double and four-fold concentrations.
Food essences should be stored in a tightly sealed glass container in the exclusion of sunlight.
The duration of storage of food essences 6 months.
Essence is bottled in glass bottles with capacity up to 25 l. The bottles are placed in baskets, cages or wooden boxes with lids and lay straw, wood shavings or sawdust.
Establishment of smell and taste
The smell and taste of flavors is established during the tasting of manufactured products. At the same time, the smell and taste of essences are best determined during tasting (in sugar syrup) 0,2% solution of essence, and essential oils and synthetic fragrances - 0,03% solution or mist.
The following essential oils can be used in the confectionery industry, if they are included in the recipe.
anise oil obtained from the fruit of anise. The oil contains up to 90% anethole. Contained in the amount of 2,2 — 3,2% by weight of the fruit.
Greypfrutovoe oil prepared from fresh peel of the fruit. The composition of oil includes about 90% d-limonene. Oil is contained in an amount 0,06% by weight of whole fruits.
Pomerantsevoe oil extracted from the rind of the fruit of Citrus aurantium L. subsp. amara L. in the number 0,15% to the weight of the rind. The oil contains more than 90% d-limonene.
orange oil obtained from the peel of the fruit Citrus sinensis in the number 0,3%. The oil contains more than 90% d-limonene.
Mandarinovoe butter extracted from the rind of mandarins. The oil yield is 0,75 — 0,85% by weight of whole fruits. This oil consists mainly of d-limonene.
Peppermint oil distilled peppermint. The output from the 0,3 1,0% up. It contains not less than 50% menthol.
Oil of spearmint is obtained from spearmint in quantities from 0,7 to 1,5%. It contains carvone, linalool and linalyl acetate.
Koriandrovoe oil receive from the dried seeds in the amount of 0,8 — 1,1%. The main component of the oil is linalool (60 — 80%) \
(melting 80,5 — 81,5 °,
The boiling point of 285 ° (does not decompose in a stream of carbon dioxide).
It is dissolved in aqueous solutions of sodium carbonate and bicarbonate. Recrystallizes from water.
Burbonal (Vanilalь) (4-oxy-Z-эtoksibenzalьdegid)
Melting point 77 — 78 °.
For confectionery products is not recommended due to the floral smell.
SN3 - CO - co - CH3.
It is used in the confectionery industry to communicate the smell of cow oil to the products. With alcohol and ether mixed in all respects. It dissolves at 15 ° in 4 water volumes.
Isoamyl ether cinnamic acid
(SN3)2 = CH - CH2- CH2 - O - OS - CH - CH - C6Н5.
It is used to enhance the flavor of the cocoa beans.
T melting 42,5 °,
Boiling point 216 °
It crystallizes in colorless needlelike and columnar crystals of the hexagonal system, which have a characteristic mint smell and cooling taste. It is poorly soluble in water, in alcohol, sulfuric ether, chloroform, fatty and essential oils - it is good.
It has the smell of hay. Melts at 67 °. It is used as an additive to other flavors to obtain a characteristic aroma.
Goryaev MI, Characteristics of chemical compounds that make up the essential oils, ed. prof. G. V. Pigulevsky, Academy of Sciences of the Kazakh SSR, 1953.
Kondratsky A.P. and Sokolnikov N.P., Guide for laboratory assistants of essential oil enterprises, Pishepromizdat, 1953
Obukhov A.N. and Kondratsky A.P., Technology of essential oil production, Pishepromizdat, 1946.
Jelly-forming substances (jelly-forming agents) are used in the confectionery industry for making jelly-like products (marmalades, marshmallows, marshmallows, and jelly candies).
The confectionery industry of the Soviet Union as gelling agents used agar, pectin and agaroid.
Foreign confectionery factories also use gelatin, alginic acid (and its compounds), carrageen extract, etc., as gelling agents.
A characteristic feature of the substances of this group is their ability to form, under certain conditions, jellies (gels), the peculiarity of which is that they easily take on any shape given to them, thus forming a more or less solid structure.
Agar is a vegetable glue found in crimson algae (the genus Anfeltia, Gelidium, and others) growing in the coastal waters of the White Sea and the Pacific Ocean.
To extract the agar, previously prepared algae (dried, cleaned from sand and silt, from mollusks and shells, soaked and washed), are boiled in hot water with the addition of alkali. The resulting broth (agar broth) is filtered, cooled to complete chilling, subjected to cutting, additional cleaning and subsequent dehydration by drying or freezing.
Chemically agar is highly polymeric polysaccharide type compound having a chain-like molecule. Individual units it consist of galactose residues.
In addition to galactose, usually calcium, magnesium, sulfur (organically bound), potassium, sodium, phosphorus and nitrogen are present in the composition of marketable agar preparations in the form of certain compounds.
After demineralization of agar (removal of Ca, Mg, K, Na), a complex organic complex is obtained, which, according to the assumptions based on recent research data, consists of a linear ester ether having the following formula:
The agar chain contains 9 residues of d-galactose, interconnected 1: 3 glucosidic bond. The chain ends with the remainder of L-galactose, which is linked to the preceding chain links through its carbon atom 4, while the sixth carbon atom is etherized with sulfuric acid.
Agar is almost insoluble in cold water, but swells in it as a colloid of limited swelling (while air-dry agar binds water in 4 — 10-fold amount to its weight).
When boiled in water agar dissolves almost completely.
From aqueous solutions, agar can be precipitated with alcohol, acetone and electrolytes.
A hot aqueous solution of agar (sol) turns into a jelly (gel), characterized by a vitreous fracture when cooled. To obtain a durable jelly amenable to cutting with a knife, it suffices from 0,3 to 1% agar to the weight of an aqueous solution (depending on the ability to gelatinize this sample of agar).
When sugar is added to an agar-water solution, jellies are obtained, the strength of which increases with increasing sugar concentration and with decreasing water content.
Agar-sugar-water jellies have a known resistance to heat. When acidifying these jellies, their resistance to heating is sharply reduced. In the presence of acid in the jelly hydrolysis of agar occurs, which weakens its capacity for gelatinization. The degradation of the jelly-forming ability of agar in an acidic environment develops especially intensively with an increase in the temperature of the medium, starting with 60 — 70 °.
According to the current GOST 6470-53, agar can be marketed in the form of porous plates with a thickness of no more than 20 mm, films with a thickness of no more than 0,5 mm, grains, flakes, powder.
Its color from white (for a premium) to yellow and light brown (for grade I).
Agar and its aqueous solutions should not be foreign smell and taste.
Agar moisture should be no more than 18%. For agar, obtained by the method of freezing, humidity is allowed up to 20%
The ash content of top grade agar should be no more than 4,5%, and in grade I no more than 7%.
The amount of nitrogenous substances, respectively, and to 1 2%.
The ability of agar to gelation is characterized by the load that the standard jelly can withstand (0,85% absolutely dry agar, 70% sugar, 29,15% water). It must be at least 1000 — 1400 g according to the device Valens to determine the strength of the jelly.
The melting point of 0,85% water jelly agar should not be lower than 80 °, and its chilling temperature should not be lower than 30 °.
Under confectionery production, the chill temperature of 1% agar jelly containing 60 — 70% sugar (and about 1% tartaric or citric acid) is within 35— -40 °.
Important when using agar in the confectionery industry has a high degree of purification of it, in particular - the lack of color (which is necessary to create a colorless background of products), the absence of foreign smell and taste.
Agar must be packed in wooden crates (lined inside with thick paper), of a net weight of not more than 20 kg, or in cardboard boxes with net weight of not more than 10 kg.
Agar should be stored in dry, well ventilated warehouse, which has no sharp fluctuations in temperature and relative humidity of not more than 80%
Shelf life of the agar for one year.