STUDY OF MICROBIAL POLYSACCHARIDES’ IMPACT ON ORGANOLEPTIC AND PHYSICAL-CHEMICAL PARAMETERS OF PROTEIN-FREE AND GLUTEN-FREE FLOURY PRODUCTS

The aim of the study is to investigate the influence of microbial polysaccharides (MPS): xampan, enposan and gellan on quality parameters of protein-free and gluten-free floury products that will widen the assortment of stiffeners of the microbial origin in technologies of gluten-free products. The formation of the required quality indicators of gluten-free dietary bakery and floury confectionery, which should be made without wheat flour, is difficult due to the lack of gluten. The search for effective structure-forming agents in place of gluten proteins is ongoing. Properties of microbial polysaccharides are considered and the possibility of their use for gluten-free products is investigated. The influence of microbial polysaccharides (MPS) of xanthan, enposan and gellan on the organoleptic parameters of protein-free bread, based on corn starch and gluten-free muffins, based on wheat germ meal was investigated. Their specific volume is determined. The structural-mechanical properties of bread crumbs and muffins on an automated penetrometer in terms of compressibility are determined. Reports on research projects (2019), «EUREKA: Life Sciences» Number 6


Introduction
For making dietary protein-free and gluten-free and healthy products, the main condition is to exclude wheat flour as a source of "problem" food proteins.
As it is demonstrated in works [1,2], gluten replacement is a serious technological problem, because it plays a main role in the structure formation of dough and baked products. It is most difficult from the technological point of view to get necessary parameters of protein-free bread, comparing with other products, because dietary requirements sternly limit protein and exclude all ingredients with its high content.
Studies [3][4][5] proved that an improvement of structural-mechanical characteristics of dough and baked products may take place at the expanse of selecting stiffeners and gel-formers that play a role of main structure-formers in gluten-free systems. Such stiffeners as pectin, carboxymethyl cellulose, agar, guar gum, xanthan essentially influence main properties of dough, based on rice flour, rice, corn and other starches and quality parameters of ready products.
A variant of overcoming difficulties of structure formation of gluten-free dough systems may be optimization of a quality content of structure-formers. Just in 2007 [6] compared different types of stiffeners and demonstrated that the presence of different hydrocolloids, such as hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC), plantain gum, carob tree fruits, guar gum and xanthan favors an increase of resistance to deformation and elasticity of gluten-free dough. It has been proved, that xanthan has the most influence on viscous-firm properties of dough that condition its strengthening. There has been established a line of the positive influence of stiffeners on the dough structure: xanthan>CMC>pectin>agar>β-glucan.
The most important factor of structure formation of protein-free and gluten-free products is, from our point of view, the use of hydrocolloids of different nature with substantiating their quantity ratio.
Xanthan (Е 415) (other names: xampan, xanthan gum) is considered as the most effective stiffener of the microbiological origin; work [7] accents that it is a key ingredient in the structure formation of products without gluten.
But there are, and appeared at the market recently also other microbial polysaccharides, that due to their construction and properties may be used in the technology of protein-free and gluten-free products. They include enposan and gellan. Despite the fact that information about enposan properties appeared long ago [9], there are not enough studies about its use in gluten-free and protein-free products. Gellan (Е 418) has a status of food supplement and is used as a stiffener and gel-former in food industry; alongside with it there are no systematized data about its influence on properties of gluten-free products. Their main characteristics together with xanthan are presented in Table 1.
Although enposan and gellan have properties and construction, similar to xampan, their technological potential as to the influence on organoleptic and physical-chemical parameters of products is not fully estimated, especially in gluten-free dough systems.
The aim of the study is to investigate the influence of microbial polysaccharides (MPS): xampan, enposan and gellan of quality parameters of protein-free and gluten-free floury products that will widen the assortment of stiffeners of the microbial origin in technologies of gluten-free products.
The following tasks were set for attaining this aim: -to study the influence of xampan, enposan and gellan (MPS) on organoleptic parameters of products; -to study the influence of MPS on structural-mechanical properties of products' crumb and specific volume. Table 1 Characteristics of xanthan, enposan and gellan

Хаnthoтопаs саmpеstris
Heteropolysaccharide, consisted of β-D-mannose, β-D-glucuronic acid and α-D-mannose. Molecular mass 1000-2000 kDa Extracellular heteropolysaccharide. Remains of glucuronic acid and acid grapevine group add the anion character to its molecules. It forms rather viscous water solutions at the small concentration. Viscosity of solutions almost doesn't depend on the influence of рН value of a medium. It demonstrates the viscosity stability of solutions at changing ionic force, heating or freezing, effect of enzymes, chemical substances. The process of jelly formation is possible at using it with separate galactomannans that synergism is observed with [8]. Polymixan is very similar to xanthan by its physical-chemical properties. It is used as a stiffener and stabilizer in many industrial branches [9].

Sphingomonas Elodea (earlier Pseudomonas elodea)
Heteropolysaccharide of the linear construction, which molecules consist of iterative tetrasaccharide pyranose rings of 1.3-β,D-glucose, 1.4-β,D-glucuronic acid, 1.4-β,D-glucose and 1.4-α,L-rhamnose. Molecular mass is near 500 kDa It has jelling, stabilizing and film-forming properties. Forms jellies with almost all ions, but demonstrates relationship with bivalent ions, much stronger than with monovalent ones. Bivalent ions of calcium and magnesium provide the optimal firmness of gellan jellies, stable to the temperature influence and enzyme effect, stable in рН diapason 3.5...8.0, [10].
Protein-free bread was produced by the following recipe ratio of components: corn starch -100.0, peeled rye flour -5.0, kitchen salt -2.5, sugar -4.0, sunflower oil -5.0, dry yeast -0.8 and MPS -0.3, water -by the calculation for dough humidity 49 %; bread, prepared by this recipe without adding MPS was a control.
Organoleptic parameters of the baked products were determined by assessment criteria of products' quality by test laboratory baking in 6 hours after baking [11].
Structural-mechanical properties of products' crumb were determined by the conventional method by a compressibility parameter on the automated penetrometer AP-4/2, made by "Finemass", Germany [11].
The specific volume of samples of the baked products was calculated by the formula where V -sample volume, cm 3 , m -sample mass, g. The samples' volume was determined by the conventional method on the special device (volume measurer) that functions by the principles of powdery filler displacing by bread. Millet was used as the powdery filler [11].
The error value for all studies was s=3…5 %, number of iterations of the experiments -n=3, probability -P≥0.95.

1. Experiments
It has been demonstrated, that the use of xanthan, enposan and gellan in amount 0.3 % of the starch mass provides formation of the needed dough structure for protein-free bread, prepared by the aforesaid ratio of recipe components.
The organoleptic parameters of such baked protein-free bread are presented in Table 2, and its outlook on Fig. 1. Table 2 The organoleptic parameters of protein-free bread with using microbial polysaccharides  The results of studying the influence of microbial polysaccharides on physical-chemical parameters of baked protein-free bread are presented in Table 3. The use of microbial polysaccharides as structure-formers in gluten-free floury confectionary products was substantiated on the example of muffins. Wheat germ meal (WBM) was used in recipes of muffins as gluten-free flour.

Food Science and Technology
This meal forms after extraction of germ oil by ethyl alcohol and differs by the high content of proteins and carbohydrates. Carbohydrates are presented in almost 60.0 % by the complex of polysaccharides that belong to dietary fiber (cellulose, hemicelluloses, lignin and pectin substances). That is why meal is considered as an effective improver by protein and dietary fiber. It also contains vitamins of B group, vitamin Е, PP, carotenoids and mineral substances. At that meal is produced in Ukraine, and its production favors solving questions of complete processing of raw materials in Ukraine. At the complete replacement of wheat flour by WBM there takes place the maximal use of the improving supplement.
It is demonstrated, that the use of WBM in amount 0.1 % of the product mass in dough for muffins provides the formation of needed rheological properties of dough that may be formed by the method of transplanting. The research results of the influence of the aforesaid amount of MPS on the organoleptic parameters of the baked gluten-free muffins are presented in Table 4, and their outlook in cut -on Fig. 3. Table 4 The organoleptic parameters of muffins with using wheat germ meal The results of studying the influence of microbial polysaccharides on physical-chemical parameters of the baked gluten-free muffins with wheat germ meal are presented in Table 5.

Results
At adding xanthan, enposan and gellan, there was not revealed an essential difference between them in the influence on the formation of organoleptic parameters of bread. As it is seen on Table 2, products with adding all microbial polysaccharides had the well developed porosity, nonsticky crumb, even surface without cracks and gaps. Bread without MPS had the weakly developed porosity, big cracks on the surface, sticky crumb. It may be stated, that adding microbial polysaccharides favors the formation of the necessary organoleptic parameters. Crumb of protein-free bread was similar to wheat one by them.
The obtained data on the photo (Fig. 1) testify to the formation and fixation of the porous structure of protein-free bread at using microbial polysaccharides.
As it is seen on Table 3, adding MPS in amount 0.3 % of the starch mass increases the specific volume of the products, comparing with the control. The most effect is demonstrated by xanthan -the parameter increases its value by 36 %, the least one -by gellan, the parameter increases its value by 33 %. The crumb compressibility on the penetrometer improves too that testifies to the elastic crumb structure formation. It is known, that the specific volume of floury products is provided by the ability of gluten and other proteins, included in the dough system, to fix the fluffy structure at baking. Although at adding MPS there takes place the improvement of the products' specific volume and compressibility on the penetrometer, it may be assumed, that swollen microbial polysaccharides together with proteins of other components play the role of gluten in a gluten-free dough system and provide the porous structure formation of these products.
The dough for muffins essentially differs from the protein-free bread dough by structure, it contains more moisture, includes protein-containing milk and egg products that participate in the formation of organoleptic parameters and structure of the gluten-free confectionary product.
The data of Table 4 show that muffins with the complete replacement of wheat flour by wheat germ meal have the pleasant organoleptic quality parameters. But these products have the small volume, not elastic excessively crumbling crumb at the expanse of absence of gluten proteins and starch of wheat flour, responsible for the products' structure formation. The addition of xanthan, enposan and gellan in muffins, based on wheat germ meal, improves the organoleptic parameters of the products. They have the equal influence on these parameters. Muffins with MPS have the perfect outlook, cracks on the surface, typical for these products. The products have soft, elastic crumb, not powdery not crumbling.
As it is seen on Table 5, adding MPS in amount 0.1 % of the ready product mass increases the specific volume of muffins. Thus, at adding xanthan, the specific volume of products increases by 14.3 %, ensospan -by 10.7 %, gellan -by 3.5 %. The crumb compressibility of products increases too. At adding xanthan it increases by 20 %, ensopan -by 16 %, gellan -by 10 %. At that xanthan in gluten-free dough for muffins also demonstrates the most influence, gellan -the least one.
In general it may be said, that MPS participate in the creation and support of the dough structure, in such a way providing the formation of organoleptic and physical-chemical parameters of gluten-free products.

Conclusions
1. The addition of microbial polysaccharides favors the creation of the needed organoleptic parameters of protein-free bread, based on corn starch. The products have the well developed porosity, non-sticky crumb, even surface without cracks and gaps. At that the specific volume of the products and structural-mechanical parameters of crumb improve. The formation of the products' porous structure is provided at baking.
2. The use of MPS in gluten-free muffins, based on wheat germ meal, provides the formation of soft, well picked, elastic crumb. At that the specific volume and structural-mechanical parameters of muffin crumb improve.
3. All studied MPS demonstrate the equal type of influence on physical-chemical parameters of products, but the most effect is demonstrated by xanthan, the least one -by gellan.
4. The studies demonstrated the possibility of using enposan and gellan as structure forming raw materials in gluten-free products. But a mechanism of forming the crumb structure of products at baking with the presence of microbial polysaccharides and their influence on the quality preservation at storage remain incompletely studied. So, further studies as to the influence of MPS on organoleptic and physical-chemical parameters of products at storage are promising.