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Table 1. - The basic indicators of porous system of a kernel of olive seeds
Kernel Volume density, Volume of the General Surface area of
g/cm 3 pore, mm 3/g porosity,% the pores, m 2/g
Cotton 1.155 78.269 9.046 7.376
Safflower 0.984 212.048 20.874 5.976
Rape 0.961 154.181 14.827 10.272
Distribution of the pores and capillaries in the sizes in a range 37-1000000 A are resulted in table 2. Table 2. - Intervals of display of the maximum maintenance of pore groups in the kernel of olive seeds
Kernel Intervals of maximums, Â
Cotton 37-720; 720-42000; 100000-1000000
Safflower 37-600; 1000-10000; 20000-1000000
Rape 37-600; 7000-320000
As we see in data of table 2, received experimental results have the extreme character.
On the assumption of this the kernel of rape can be considered as bidispersed porous part, and the kernels of cotton and safflower to trydispersed porous parts.
Discussion: By researches on the example of seeds of cotton it is established that oil in the cell is localized in spherosomes which together with albumin globules fill all volume of the cell.
At electron-microscopic level it has been revealed that in the microstructure there are pores, capillaries and
air emptiness. Cells of fabrics consist of cellular walls and set of the various structural characteristic details different by the sizes including lipid spherosomes, protein bodies containing spare fibers or globulin, globoids, cellular cytoplasm in which all elements set forth above are introduced together with a water-soluble protein, enzymes and other functional components, i. e. the structure of a kernel of olive seeds is simultaneously multicomponent and heterogeneous, and that predetermines selective character of the response of separate components on action of external fields.
References:
1. Tyutyunnikov B. N. Chemistry of fats. - M.: Food industry. - 1974. - P. 448.
2. Physiology and biochemistry ofrest and germination of seeds//translated from English - M.: Kolos, - 1982. - P. 495.
3. Proteins of seeds of grain and olive cultures//translated from English - M.: Kolos, - 1977. - P. 312.
4. Scherbakov V. G. Biochemistry and merchandising of oil-bearing raw materials. M.: Agropromizdat. - 1991. - P. 356.
5. Bikova S. F. Theoretical and experimental bases of creation of essentially new resource-saving technologies of reception of vegetable oils/S. F. Bikova: Abstract of a thesis of doctor of technical sciences, St. Petersburg, - 1996.
D OI: http://dx.doi.org/10.20534/AJT-16-11.12-25-31
Sulaymanova Gulchekhra Hakimovna, Majidov Kahramon Halimovich Bukhara engineering technological institute, Bukhara, Uzbekistan E-mail: kafedra-03@mail.ru,
Cream-superficial activity of food emulsifiers
Abstract: One of perspective directions ofdevelopment ofbutter industry is working out and development of manufacture of butter with the lowered fat content. Now manufacture of such butter has not found a wide prevalence yet. Taking into account were carried out researches of influence ofstabilizers ofstructure on properties of cream with a mass fraction of fat of 40-60% as raw materials for development of oil with the lowered fat content. As the consistence stabilizer used gelatin in quantity from 0 to 2%, as emulsifiers — monoglycerides.
As estimation criteria were used effective viscosity, sedimentation stability of system. Viscosity of cream of 4050% fat content at entering of emulsifiers changed slightly. At mass fraction of fat more than 60% entering of emulsifiers in cream promoted increase in their viscosity in 1.4-2.1 times. Considerable changes ofviscosity were observed at entering ofstabilizers into cream. Thus viscosity ofcream of50% fat content came closer to viscosity of control samples at entering into them of the mixture of the stabilizer in quantity of 1% and emulsifiers in quantity of 1%. Viscosity of cream of 40% fat content with addition of the stabilizer less than 2% was lower than viscosity of the control sample, and at a dose of the stabilizer of 2% or its mixtures with emulsifier (0.5% and 1%) was exceeded by viscosity of the control sample in 1.3-1.9 times. Viscosity ofcream of60% fat content at entering into them of 0.5% emulsifiers already was higher than viscosity of control samples in 1.3 times.
Keywords: Dairy butter, fat mass fraction, stability, properties of cream, viscosity and sedimentation stability, maintenance of emulsified fat.
Introduction: Expansion of assortment of articles of food including fat-and-oil products is important problem of food-processing industry in the next years. In this direction ways and measures on overcoming of world financial and economic crisis are considered as the basic program document of Republic of Uzbekistan [1].
The great attention all over the world is given to a problem of a rational and adequate food. In the decision of this problem the important place has expansion of assortment of a foodstuff with the raised food value at the expense of use of additives with functional properties.
Food fats are the important foodstuff. On the physiological norms, the recommended maintenance of fat in a food allowance of the person makes 30-33% — the general power value of food.
Fats are necessary not only as reserve substance and energy source, but also as suppliers of physiologically active connections — irreplaceable fat acids, phosphatides, sterols, vitamins participating in synthesis of cellular membranes and other fabrics of an organism.
Purpose of the scientific work: Decision of problems of quality and safety of food fats and products of their processing is one of priority directions in realization of the concept of state policy in the field of healthy food of the population of republic.
Materials and methods: For analysis of a chemical compound offats and products ofdecay ofthe catalyst were used methods selective extraction, gas-liquid and thin-layer chromatography and nuclear magnetic resonance [2].
The maintenance of trans-isomers defined by the IR-spectroscopy method; separation of triglycerides on molecular weight by the method of high-temperature gasliquid chromatography [3].
Analysis of positional separation of fat acids in triglycerides was defined by the method of enzymatic hydrolysis with the subsequent calculation of triglyceride structure [4].
Maintenances of monoesters of fat acids, mono-di — and triglycerides defined by the method of thin-layer and gas-liquid chromatography.
The polymorphic crystal structure of fat was studied by the method of X-ray diffraction and the differential-thermal analysis [5].
Results and discussion: One of perspective directions of development of butter industry is working out and development of manufacture of butter with the lowered fat content. It will be co-ordinated with requirements of time and the basic tendencies of butter manufacture in the world [6].
Now manufacture of such butter has not found a wide prevalence yet. It is connected by that decrease in a mass fraction of fat in cream promotes deterioration of conditions of process of oil formation, to infringement of its stability and formation of defects of oil consistence (friability, crumbling, exudation of moisture, disconnectedness of structures, etc.). The reason of it is change of physical and chemical properties of the cream, making direct impact on process of butter forming.
At decrease in a mass fraction of fat in cream from 70 to 40% is observed reduction of their effective viscosity and sedimentation stability, maintenance increase of emulsified fat and decrease in ability to transformation of a dispersion of direct type to a dispersion of return type, characteristic for a butter of traditional structure.
One of possible ways of influence on process of butter forming from dispersions of the lowered fat content is entering into cream of stabilizers of structure — the substances, capable to change physicochemical properties of cream of the lowered fat content so that they as much as possible came closer to high-fatty cream, process of butter forming which proceeds stably. It is possible to refer to them emulsifiers (E) and consistence stabilizers (St).
As emulsifiers are used fat-soluble substances possessing high superficial activity owing to presence in
them polar located hydrophilic and lipophilic groups of atoms. Such structure of emulsifiers causes their ability to concentrate on interfaces of phases, to reduce an interphase tension and to promote formation and stabilization of a fatty dispersion.
As consistence stabilizers are used water-soluble substances possessing expressed hydrophilic properties. Because of this property they allow to keep moisture in a product and keep physical and chemical condition and uniformity formed at participation ofemulsifier dispersions.
Positive influence of emulsifiers and consistence stabilizers on process of butter forming is established at development of sandwich fat with a mass fraction of 61.5%. However their influence on cream with lower mass fraction of fat and process of their transformation to oil are studied insufficiently.
Taking into account were carried out researches of influence of stabilizers of structure on properties of cream with a mass fraction of fat of40-60% as raw materials for development of oil with the lowered fat content. As the consistence stabilizer used gelatin in quantity from 0 to 2%, as emulsifiers — monoglycerides distilled under trademark "Palsgaard-0291" in quantity from 0 to 1% [7].
As estimation criteria were used effective viscosity, sedimentation stability of system (cream + St; cream + E; cream + St +E), organoleptic indicators (taste and smell, consistence), maintenance of emulsified fat, ability of system to destruction under the influence of thermo-mechanical processing, microstructure of mixtures. As the control product was used cream of 70% fat content without structure stabilizers.
Experiment planning was carried out as full factorial experiment.
The estimation of taste and smell of analyzed samples on specially developed 5-mark scale was in a range of 2.5-4.5 points. For mixtures with a mass fraction of fat of 40% most the appreciation was received by samples with addition of the stabilizer in quantity of 2% or its mixtures with emulsifiers; for mixtures of 50% fat content — samples with addition of the stabilizer of 1% or its mixtures with emulsifiers, and for mixtures of 60% fat contents — samples with emulsifier in quantity of 0.5%. The consistence of analyzed cream was in a range of 1-4 points. Thus for all analyzed samples of cream the tendency of improvement of the consistence was traced at use of structure stabilizers.
Viscosity of cream of 40-50% fat content at entering of emulsifiers changed slightly. At mass fraction of fat more than 60% entering of emulsifiers in cream promoted increase in their viscosity in 1.4-2.1 times.
Considerable changes of viscosity were observed at entering of stabilizers into cream. Thus viscosity of cream of 50% fat content came closer to viscosity of control samples at entering into them of the mixture of the stabilizer in quantity of1% and emulsifiers in quantity of 1%. Viscosity of cream of 40% fat content with addition of the stabilizer less than 2% was lower than viscosity of the control sample, and at a dose of the stabilizer of 2% or its mixtures with emulsifier (0.5% and 1%) was exceeded by viscosity of the control sample in 1.3-1.9 times. Viscosity of cream of 60% fat content at entering into them of 0.5% emulsifiers already was higher than viscosity of control samples in 1.3 times.
Increase of viscosity of system at addition of stabilizers is caused by formation of additional structural bonds in it that was confirmed by microscopic researches on example of cream of 50% fat content (fig. 1).
At research of sedimentation stability of cream with addition of stabilizers and emulsifiers it is not established any law of its change depending on a mass fraction of fat, dose of the stabilizer and emulsifiers. In some samples is noted the increase of sedimentation stability in comparison with cream of similar fat content without structure stabilizers, in others, on the contrary, its decrease. Average indexes of sedimentation stability on the sediment of fat for cream of 40% fat content with addition of stabilizers of structure have made 81.8%, for cream of 50% fat content — 84.8%, and for cream of 60% fat content — 81.9%. For control cream of 70% fat content this indicator has made 96.0%. On the average at entering of stabilizers of structure sedimentation stability of cream much lower than at control samples. The maintenance of emulsified fat in cream of 40-60% fat content at entering into them emulsifiers tends to growth, and at entering of stabilizers — to decrease. At sharing of emulsifiers and stabilizers the maintenance emulsified fat in cream 40-60% fat content also tend to decrease.
For an estimation of ability of analyzed cream to destruction under the influence of thermomechani-cal processing of the mixture after pasteurization was cooled to temperature of butter forming and destroyed. In an initial mixture and the received product were defined the maintenance of emulsified fat and calculated ability of system to destruction on parity of maintenance of emulsified fat in the dispersion before and after its destruction. Also hereby established that cream with mass fraction of fat of 40% can collapse under the influence of the mechanical and temperature factor on 90% and more only at addition in them of the stabilizer in quantity of 2% (or its mixtures with emulsifier). The same
degree of destruction of cream with a mass fraction of fat of 50% is observed at entering of 1% and more stabilizer and its mixtures with emulsifier. The cream with the mass fraction of fat of 60% most easily collapse at
entering of emulsifiers in quantity of 0.5%. The obtained data accurately shows the tendency of increase in ability of cream to destruction, i. e. to transformation to oil, at use of stabilizers and emulsifiers.
Figure 1. Change of a microstructure of cream at content), х280: a- control; b- with addition of 1%
Definition of optimum doses of the stabilizer and emulsifiers at which change of initial cream occurs in a direction of reception of system with indicators close to control cream is carried out by the method of the multifactorial analysis of experimental data.
Factors: хх— fat mass fraction in cream in a range of 40-60%; х2 — mass fraction of the stabilizer of 0-2%; х3 — mass fraction of emulsifiers of 0-1%.
Target parameters: у1 — taste and smell; у2 — consistence; у3 — viscosity; у4 — ability to destruction (as an indicator uniting condition of dispersion before thermomechanical processing).
The equations of regress describing dependence of indicators у1 - у4 from factors х1 - х3 are received. All equations of regress are adequate; the plural factor of correlation varies from 0.83 to 0.92. At the fixed values of the mass fraction of fat in cream (хх) in the received equations are established dependences of analyzed indicators (у1 - у4) from factors х2 and х3 at change of fat content of cream from 40.0 to 60.0% with step of 2.5%. On sections of response surface (fig. 2) were defined areas of values of mass fractions of the stabilizer х2 and emulsifiers х3 at which indicators of
entering into them of structure stabilizers (50% fat emulsifiers; c- with addition of the stabilizer of 2%
analyzed mixtures of the fixed fat content come closer to control cream.
Analyzing the received results, it is possible to notice that for cream with a mass fraction of fat of 40% the optimum area has narrow enough range: х2 = 1.701.85%, х3 = 0.40-0.75%. It is limited with discrete step of all analyzed parameters, and in a greater degree with discrete step у3 у2 у.. In optimum area the stabilizer mass fraction has narrower range.
Reduction of its fraction below optimum value leads to decrease in viscosity of system and its ability to destruction. Simultaneously thus worsen organoleptic indicators of cream (taste, smell and consistence).
At definition of optimum areas for cream 42.560.0% fat content the taste and smell estimation has appeared less significant at у. In a range of fat content from 45.0 to 52.5% physical and chemical indicators were defining (viscosity y3 and ability to destruction у4), i. e. in this range entering of stabilizers of structure makes stronger impact on viscosity of cream and ability to destruction than on their taste, smell and consistence.
At higher mass fraction of fat in cream (55.0-60.0%) the big importance in definition of optimum area has viscosity of system — y3 and its consistence — y2. It is possible to explain it that in the given range of fat
content the superfluous quantity of the stabilizer leads to inflation of viscosity of system, occurrence of its excessive density and stickiness and to deterioration of its consistence.
Figure 2. Optimum areas of sections of response surface for dairy-fatty dispersions with the fat mass fraction 40% (a); 42.5% (b); 45% (c); 47.5% (d); 50% (e); 52.5% (f); 55% (g); 57.5% (h); 60% (i). On an axis of abscissa — stabilizer mass fraction х2 (%), on an axis of ordinates — emulsifiers mass fraction х3 (%)
The area of optimum zone of sections of response surface grows with increase in the mass fraction of fat in system from 40.0 to 55.0%, and then decreases in process of growth of a mass fraction of fat. It is necessary to notice that for dispersions with a mass fraction of fat of 40.0-42.5% sharing of the stabilizer and emulsifiers is obligatory. For dispersions with a mass fraction of fat of 45.0-60.0% probably use of two variants: mixtures of the stabilizer with emulsifier or only the stabilizer, i. e. the stabilizer in an analyzed range of fat content of cream makes more significant impact on change of their indicators, rather than emulsifier. As lower fat mass fraction in cream that as higher importance of the stabilizer. At decrease in a mass fraction of fat from 60 to 40-45% the parity of St/E increases from 0.99 to 3.10-3.44.
For each level of fat content of cream on optimum areas it is possible to define minimum E , average E
x mm' C» av
and maximum E quantity of emulsifiers at which ad-
max A J
dition it is possible to receive cream with the set properties. Optimum values of a mass fraction of stabilizer St at these fractions of emulsifiers are presented in table.
The minimum value of emulsifiers for dispersions of various level of fat content makes from 0 to 0.4%, maximum — from 0.75 to 1.0%. Average value of emulsifiers makes from 0.38 to 0.60%. At increase of dose of emulsifiers from E to E (in 2 and more times) the optimum
min max v ' i
dose of the stabilizer decreases in 1.1-1.6 times. Thus dose application of emulsifiers in limits from minimum to an average of values is economically more proved.
At the minimum value of emulsifiers, equal to zero (Emin = 0), dependence of a mass fraction of the stabilizer x2 from fat content of cream x1 in a range 45.0-60.0% are described by the equation
x2 =-3,76 + 0,2923Xj -0,003695x2 (R =0.99). (1)
At average value of emulsifiers Eav dependence of a mass fraction of the stabilizer on fat content of cream in a range 40.0-60.0% are described by the equation x2 =-3,316 + 0,2647x1 - 0,003407x2 (R = 0.99). (2) Dependence of a parity of St/E (x2/x3) from a mass fraction of fat of cream is described by the equation x2 / x3 =-13,18 + 0,7554x1 - 0,008718x2 (R = 0.97).(3)
Table 1.
From the equation (1) it is possible to define demanded mass fraction of the analyzed stabilizer in a range of fat content from 45 to 60% which allows receiving mixtures with organoleptic and physicochemical indicators which are closer to control cream, without usage of emulsifiers.
Mass fraction offat,% E . ,% mm' St,% E .% av St,% St/E E % max, St,%
40.0 0.4 1.82 0.58 1.78 ± 0.02 3.10 0.75 1.70
42.5 0.2 1.75 0.60 1.72 ± 0.10 2.87 1.0 1.55 ± 0.10
45.0 0 1.87 ± 0.13 0.50 1.72 ± 0.10 3.44 1.0 1.52 ± 0.13
47.5 0 1.83 ± 0.17 0.50 1.63 ± 0.22 3.26 1.0 1.40 ± 0.20
50.0 0 1.65 ± 0.30 0.50 1.43 ± 0.28 2.86 1.0 1.20 ± 0.35
52.5 0 1.40 ± 0.40 0.50 1.17 ± 0.38 2.34 1.0 1.08 ± 0.27
55.0 0 1.08 ± 0.42 0.50 0.87 ± 0.48 1.74 1.0 0.83 ± 0.22
57.5 0 0.82 ± 0.30 0.50 0.65 ± 0.22 1.30 1.0 0.63 ± 0.05
60.0 0 0.50 ± 0.20 0.38 0.37 ± 0.15 0.99 0.75 0.30
From the equation (2) it is possible to define demanded mass fraction of the stabilizer in a range of fat content from 40.0 to 60.0% at its sharing with emulsifier. Having defined value x2 and having substituted it in the equation (3), it is possible to calculate demanded value x3 for any analyzed fat content of cream.
Thus, the conducted researches have allowed to establish emulsifiers (distilled monoglycerides) and the stabilizer (gelatin) on change of properties of cream of 40-60% fat content and to define influence their optimum doses, allowing to approach properties of cream of the lowered fat content to cream of 70% fat content (without structure stabilizers) and by that to improve conditions of their transformation to a ready product — butter with the lowered fat content.
Conclusions: Basis of emulsifying ability of different soluble emulsifiers, including food emulsifiers, is their superficial activity.
Except property of emulsifiers — to lower a superficial tension on border of section of phases as a result of spontaneous concentration of its molecules in the superficial layer — necessary conditions of stabilization of concentrated emulsions are density of the protective layers stabilizing emulsions, and presence of the structurally-mechanical barrier which is carried out by permolecular structures in the form of phase superficial films of emulsifiers.
For achievement of enough high structural viscosity — durability of covers of droplets of emulsion — in
them should occur micellar structuration with occurrence of lyophilic gel as a result of concentration increase of its superficial-active substance in adsorption layer
Basically asymmetry of structure of molecules of superficial-active substance is observed only in solutions of superficial-active semicolloids in which the certain fraction of all dissolved particles is in colloid-disperse condition, and other part — in molecular-disperse condition.
Mono- and diglycerides are received by etherifica-tion of glycerin with fat acids or glycerosis of food fats and oils. Glycerosis of fats is an exchange of radicals between triglycerides and glycerin, being special case of interesterification. Used as emulsifier the product of glycerosis contains 35-70% of monoglycerides, 30-40% of diglycerides, 10-20% of triglycerides, and the rest part — glycerin and fat acids. Concentrated monoglycerides are received by molecular distillation.
On research of superficial activity of the technical mixture of mono-, di- and triglycerides in comparison with pure monoglycerides, allocated with molecular distillation, it is shown that monoglycerides lower the superficial tension on border of cotton oil-water system at temperature 70 °C much more strongly than a mixture of mono- and diglycerides.
Decrease ofa superficial tension depends on length of the hydrocarbonic chain of a radical of fat acid of mono-glyceride, exactly: superficial activity of monostearate is less than glycerin monopalmitate and monolaurate, i. e. superficial activity of these substances from nonaqueous
solution increases on border with water with reduction of a hydrocarbonic chain that is typical for all hydrophobic superficial-active substances.
Researches of a superficial tension of solutions of some glycerides in cotton oil on border with water are conducted. Superficial activity for solutions of mono-glycerides of caprylic, capric, lauric, palmitic, linoleic and oleic acids has been thus studied at various temperatures.
At analysis of a superficial tension of solutions of monoglycerides ofstearin, pelargonic, 12-hydroxystearin, 9.10-dihydroxystearin and 9.10.12-trihydroxystearin acids has been noted difficult solubility of di- and trihydroxy-monoglycerides in cotton oil, therefore measurements of superficial tension ofthese monoglycerides carried out for their water solutions on border with cotton oil.
Superficial tension of solutions glycerin monostea-rate in cotton oil was measured on border with water. It has been thus shown that superficial activity, for example, glycerin monostearate, approximately in 6 times lower than 9.10.12-trihydroxymonoglycerides.
Definition of factor of superficial activity of a -mono-stearate and butyl alcohol at its calculation under the empirical formula has shown that at temperatures lower than 40 °C the formula ceases to be true.
Thus, the given researches can be a basis for practical use of monoglycerides on the basis of different fatty raw materials in this or that technological process by manufacture of food production, because the properties, nature, chemical structure of superficial-active substances cause character of interaction with them entered systems.
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6. State Standard P 53776-2010. Refined and deodorized palm oil for food industry. Technological conditions. Introduction. - 2011. - 04-01. - M.: Standartinform, - 2010 - P. 16.
7. Arutunyan N. S., Kornena E. P., Yanova L. I., and other. Technology of processing of fats. - M: Pishepromizdat, -1999. - P. 452.
8. Kornena E. P., Kalmanovich S. A., Martovshuk E. V. and other. Assessment of oils, fats and products of their processing/Edited by Pozdnyakovskiy V. M. - Novosibirsk, - 2007 - P. 272.
9. Sulaymanova GH, Rahimov MN, Madjid KH The influence of electromagnetic fields on the degree of purification cottonseed oil. Magazine "Fat industry" - Moscow, - 2015. - No 5. - S 18-19.
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