INTRODUCTIONNutrition is a vital element of human interaction withthe environment that has a decisive influence on humanhealth, performance, and resistance to harmful effectsof production and environmental factors. A regulardiet of nutritious foods containing vital substances isparticularly important for maintaining human health andactivity in old age.Nutrition issues are a major physiological andhygienic problem. Studies have shown a recent decreasein the consumption of meat, dairy, and fish products,as well as fresh vegetables and fruits among certaingroups of Russian population. Another negative fact isa decline in energy intake from food (91%), especiallydue to a reduced amount of animal proteins in the diet.Moreover, certain groups consume only 55–60% of therecommended content of vitamins* [1–3].The importance of enriching foods with varioussubstances for health improvement purposes is specifiedin the Decree of the RF Government No. 1134-r of June30, 2012 (amended on February 6, 2014) ‘On approvingResearch Article DOI: http://doi.org/10.21603/2308-4057-2019-2-387-395Open Access Available online at http:jfrm.ruDietary fibres in preventative meat productsEvgeniy I. Titov1 , Alexander Yu. Sokolov2 , Elena V. Litvinova1,* , Sergey N. Kidyaev1 ,Daria I. Shishkina2 , Boris A. Baranov21 Moscow State University of Food Production, Moscow, Russia2 Plekhanov Russian University of Economics, Moscow, Russia* e-mail: llusionse@mail.ruReceived July 18, 2019; Accepted in revised form July 29, 2019; Published October 21, 2019Abstract: This paper is based on literature and our own studies of high-quality dietary fibres of various types, as well as foodmaterials and products. It provides data on the physiological features, functional and technological properties of dietary fibre, aswell as its main uses in food technology. In particular, we assessed the texture of dietary fibre, constructed rheograms for the flowof fibre-water systems, and analysed the histological structure. Our results form a scientific basis for the development of safe meatproducts of high quality and healthy diets. We established specific structural characteristics, properties, and rheological behaviourof various dietary fibres, as well as their advantages. We found that potato fibres demonstrated greater uniformity in texture andrheology, compared to wheat fibres. Wheat fibres had a clear phase structure (fibre/water), whereas potato fibres showed significanthydrophilic and structuring properties, attributing them to colloidal fibres. The established patterns contribute to the rational selectionof dietary fibre to create products with desired properties. In particular, we developed a technology for a restructured poultry productwith preventative properties using soluble and insoluble dietary fibres. The paper provides data on the product’s safety indicators,nutritional and biological values, as well as functional, technological, microbiological, and other properties. We also conductedmicrostructural studies to analyse the uniformity of distribution of the curing mixture in the developed meat product. We concludedthat using potato and wheat fibres can expand the range of meat products in line with the concepts of rational and healthy nutrition,as well as increase the product’s succulence and prevent syneresis and mass loss.Keywords: Dietary fibre, diet, rheogram, histological structure, food, poultryPlease cite this article in press as: Titov EI, Sokolov AYu, Litvinova EV, Kidyaev SN, Shishkina DI, Baranov BA. Dietary fibres inpreventative meat products. Foods and Raw Materials. 2019;7(2):387–395. DOI: http://doi.org/10.21603/2308-4057-2019-2-387-395.Copyright © 2019, Titov et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 InternationalLicense (http://creativecommons.org/licenses/by/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix,transform, and build upon the material for any purpose, even commercially, provided the original work is properly cited and states its license.Foods and Raw Materials, 2019, vol. 7, no. 2E-ISSN 2310-9599ISSN 2308-4057* MR 2.3.1.2432-08. Normy fiziologicheskikh potrebnostey v ehnergiii pishchevykh veshchestvakh dlya razlichnykh grupp naseleniyaRossiyskoy Federatsii [Methodological Guidelines 2.3.1.2432-08.The norms of physiological requirements for energy and nutrients forvarious population groups in the Russian Federation]. Moscow: FederalCenter for Hygiene and Epidemiology of Rospotrebnadzor; 2009. 36 p.** Rasporyazhenie Pravitel’stva RF №1134-r ot 30.06.2012 (red. ot06.02.2014) ‘Ob utverzhdenii plana meropriyatiy po realizatsii osnovgosudarstvennoy politiki Rossiyskoy Federatsii v oblasti zdorovogopitaniya naseleniya na period do 2020 goda’ [Decree of the RFGovernment No. 1134-r of June 30, 2012 (amended on February 6,2014) ‘On approving an action plan to implement the principles of theRussian Federation state policy in the field of healthy nutrition for theperiod until 2020’]. 2012.388Titov E.I. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 387–395an action plan to implement the principles of the RussianFederation state policy in the field of healthy nutritionfor the period until 2020’**.Meat works are forced to use polysaccharidestructure-forming agents, such as carob bean gum,carrageenans or alginates to improve food consistencyand increase not only the output, but also economicindicators. This raises the price and adds more Enumbers on the food labels, which is negativelyperceived by the consumer [4].Current trends in healthy nutrition demonstrate aneed for low energy meat products with a minimum fatcontent, higher protein content, and special substancesthat improve digestion, absorption, and metabolism [5–7].Modern scientific aspects of physiology andbiochemistry encourage food experts and manufacturersto change requirements for food production. Theydevelop new formulations and adjust the amount ofnutrients and fibres in accordance with a person’sphysiological and professional status, as well as climaticand social living conditions.Dietary fibres are increasingly used not only in theproduction of specialised foods, but also products ofmass consumption. The reasons for their popularityinclude improved gastrointestinal motility (accordingto Ugolev’s theory of adequate nutrition), minimumenergy value, the ability to bind moisture and fat (takinginto account a large amount of refined foods in the diet),structural variety, and safety of use [8, 9].The daily intake of dietary fibre is 25–35 g. Today,nutritionists recommend increasing this amount to 40–42 g per day. Recent studies have found a decrease indaily fibre intake in many countries. It was revealedthat Russian population consumes only 30–35% ofthe recommended amount of dietary fibre, mostlyfrom wholemeal flour and grain. Even 30 years ago,vegetables and fruits were an integral part of Russiandiet. They are immensely rich in cellulose and thereforehave a balanced amount of soluble and insolublefibres [10]. Nutritionists recommend a 3:1 ratio of those,respectively [11].Numerous studies have proven that a deficiencyin dietary fibre causes a risk of developing variousdiseases, including irritable bowel syndrome, hypomotorcolon dyskinesia, intestinal diverticulosis, and evencolon and rectal cancer. Annually, about half a millionmalignant tumours in the large intestine are diagnosedworldwide, 35% of which are rectal cancer. Rectalcancer comes 6th or 7th on the list of all malignanttumours [12, 13].A connection was established between aconsumption of smoked or fried foods and a risk ofrectal cancer. Carcinogens (benzopyrene) that formduring such types of heat treatment cause pointmutations and translocations. As a result, cellular prooncogenesare turned into active oncogenes whichcontribute to the initial synthesis of oncoproteins andthe transformation of a healthy cell to a cancerouscell [13]. Scientists believe that dietary fibre, whenpassing through the gastrointestinal tract, adsorbs water,thereby increasing the amount of faeces. As a result,faeces move faster through the intestines, reducing therisk of colon cancer [14]. In addition, a low energy valueof dietary fibre and the feeling of fullness that it induceshelp people to control their appetite. Ballast substancescontribute to the production of insulin, which affectsblood sugar.Comprehensive studies have found that dietary fibrein functional foods affects digestion processes in thegastrointestinal tract, including symbiont digestion. Inparticular, it improves clinical and metabolic parametersby normalising the functional activity of the intestinalmicrobiota. Also, it benefits the anthropometricparameters helping to reduce body weight and waistcircumference. Therefore, dietary fibre can be used inthe treatment and prevention of obesity [15, 16].Thus, dietary fibre reduces the incidence ofatherosclerosis, obesity, diabetes, metabolic syndrome,varicose veins, venous thrombosis of the lowerextremities, etc. [17]. In addition, dietary fibre maintainsa water-salt balance in the body, contributing to theprevention of gallstone disease, and is a nutritiousmedium for beneficial intestinal microflora [18, 19].Until recently, ballast substances contained invegetables and fruits were considered the mainsources of dietary fibre. However, collagen, especiallyits fractions obtained by various methods, is just asgood functionally as its plant analogues. This meansthat protein hydrolysates and composites can also beregarded as fibrous, anisotropic, three-dimensionalfood systems [20–22]. In the growing agriculturalsector, there is a need for improving the production ofhydrolysates and concentrates of various biopolymers(polysaccharides, proteins, etc.).An important factor is that nanoclusters (forexample, in cellulose) are highly likely to preservevarious biologically active substances, which ensurestheir safety in the further cycle of food production [23].A number of studies have shown that animalanalogues of dietary fibres (in particular, modifiedcollagen and ichthys collagen) can be used as a matrixbase. For example, a study was conducted to determinethe sorption properties of collagen fermentolisate inrelation to heavy metals, using Cd2+ and Pb2+ ions. Thestudy found that the biomodified connective tissueprotein showed a similar ability to bind Pb2+ ions to thatof cellulose, for which the sorption range was 0.10−0.23 mg/g [24]. Thus, hydrolysed forms of collagenare able to bind heavy metal ions in the digestive tractto form insoluble complexes that are excreted from thebody without being absorbed. This mechanism can beused in the prevention of heavy metal salt poisoning.Of scientific interest is also the process of jointsorption of several protein components and bioactive389Titov E.I. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 387–395substances. A systematic study of the sequential andjoint sorption of several binary protein mixtures andsome bioactive substances (for example, ion-exchangecomponents of plant origin such as ascorbic acid oriodine) showed that the binding process was complicatedby synergistic phenomena. Such phenomena werepromoted by the strong binding of protein toindividual components of various nature, which can bedetermined as the number of fixed ionogenic groupsof the sorbent on one protein molecule. A decreasedlocal concentration of ionogenic groups of plant-basedbioactive components contributes to the transition to asynergistic mechanism of competitive sorption. Suchsorption of bioactive substances on a collagen-basedmatrix can preserve up to 70% of organic componentssuch as ascorbic acid or iodine that are easily destroyedby heat treatment [25].We should note that the mechanism of such sorptionhas not been established yet. However, we know thatall proteins have a pronounced ability of non-specificbinding to SH groups, the guanidine group of arginine,and other amino acid components. It is possible that thebiomodification of connective tissue contributes to thebreakdown of peptide chains of collagen. As a result, thepreviously mentioned functional groups become moreaccessible for interaction with metals and biologicallyactive substances [26].Thus, the connective tissue modified by chemical,physical or biological methods is a highly active sorbentfor heavy metals and biologically active substances. Ittherefore has a potential of being used as a functionaladditive in the production of foods, particularly meatproducts [24–27].An important issue in the context of dietary fibrephysiological properties is the consumer’s attitudeto functional components in food production. Anonline survey among young respondents using Googleservices demonstrated a positive response to functionalingredients, in particular to dietary fibre, if thenecessary information is given on the packaging [28].However, consumers are concerned about the safetyof certain ingredients. According to GRAS, refinedwheat, oat, corn, and other dietary fibres are safe to use.Most studies, both in Russia and abroad, havefocused on stabilising systems based on hydrocolloidsand composites containing several components, forexample, polysaccharide and protein composites,etc. Noteworthily, hydrocolloids can be produced byvarious methods: chemical, physical, biological, etc [4].In addition, genetic modification is now used in cropbreeding to accelerate the production of target products.However, it is extremely undesirable, especially in termsof consumer demand [28].The technological aspects of using fibrous foodsystems or compositions require a study of theirrheological properties, including viscosity, emulsifyingability, colloidal and molecular features, as well ashydration characteristics of imported and domesticadditives for better development of formulations andprocesses [29, 30].For example, a solution of carboxymethyl cellulose(CMC) from the group of colloidal fibres is characterisedby a thixotropic flow with a decrease in viscosity atconstant load and a rather significant increase in effectiveviscosity after unloading [4], as shown in Fig. 1.In connection with the above, we aimed to study therheological and microstructural properties of varioustypes of dietary fibre that contribute to a jelly-likestructure with similar mechanical and sensory propertiesto those of food raw materials, for their further joint usein the development of restructured poultry products.STUDY OBJECTS AND METHODSThis study used dietary fibres of various SuperCelgroups (manufactured by J. Rettenmaier & SoehneGmbH & Co. KG, Germany and supplied byRettenmaier Rus), namely:– insoluble: WF 200 R, WF 300 R, WF 400 R, andWF 600 R wheat fibres;– semi-soluble: KF 200 and KF 500 potato fibres; and– soluble: psyllium P 95.Nutritional value indicators were determined as follows:– moisture mass fraction: according to State StandardR 51479-99***;– protein mass fraction: on a semi-automatic TecatorKjeltec System 1002;– fat mass fraction: according to State Standard 23042-2015****;– ash mass fraction: according to State StandardR 53642-2009*****; and– carbohydrates mass fraction: by the computationalmethod.The digestibility of in vitro proteins was examinedusing the Pokrovsky-Ertanov method and a modifieddevice. The degree of dietary fibre hydration was*** State Standard R 51479-99. Meat and meat products. Method fordetermination of moisture content. Moscow: Standartinform; 2010. 4 p.**** State Standard 23042-2015. Meat and meat products. Methods offat determination. Moscow: Standartinform; 2016. 9 p.***** State Standard R 53642-2009. Meat and meat products.Determination of total ash. Moscow: Standartinform; 2010. 8 p.Figure 1 Rheogram for CMC solutionτηef.τηef.ηef.390Titov E.I. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 387–395determined visually. The Lipatov Jr. method was used tomeasure the water holding capacity of meat samples.Structural and mechanical properties of meatproducts, namely shear stress and cutting work, weredetermined on an Instron-1140 testing machine using aKramer shear press.Microbiological tests and product safety studies wereconducted in accordance with Technical Regulations ofthe Customs Union 021/2011******, 034/2013*******,and Methodological Guidelines 4.2.2747-10********.Sensory tests were guided by ISO 11037-2013********; the yield of the finished product wasmeasured by the weight method.Rheological properties were studied using anRPE-1M Polymer rotary viscometer with a T1-B1 rotor-cylinder sensing system. Microstructuralstudies of meat samples were guided by State Standard19496-2013********. They were conducted using anAxioImager A1 light microscope (Carl Zeiss, Germany),an AxioCam MRc 5 video camera, and an AxioVision4.7.1.0 computer-based image analysis system.The results were processed using standard methodsof variation statistics. The differences were consideredsignificant at a confidence interval of > 0.05.RESULTS AND DISCUSSIONThe technological properties of the dietary fibresunder study are shown in Table 1.****** TR TS 021/2011. Tekhnicheskiy reglament Tamozhennogosoyuza ‘O bezopasnosti pishchevoy produktsii’ [TR CU 021/2011.Technical regulations of the Customs Union ‘On the safety of foodproducts’]. 2011.******* TR TS 034/2013. Tekhnicheskiy reglament Tamozhennogosoyuza ‘O bezopasnosti myasa i myasnoy produktsii’ [TR CU034/2013. Technical regulations of the Customs Union ‘On the safetyof meat and meat products’]. 2013.******** MUK 4.2.2747-10. Metody sanitarno-parazitologicheskoyehkspertizy myasa i myasnoy produktsii, provodilimikrobiologicheskie issledovaniya i izuchali pokazateli bezopasnostirazrabotannykh produktov pitaniya [Methodological Guidelines4.2.2747-10. ‘Methods of sanitary and parasitological examination ofmeat and meat products’]. 2011.******** State Standard ISO 11037-2013. Sensory analysis.Guidelines for sensory assessment of the colour of food products.Moscow: Standartinform; 2014. 16 p.******** State Standard 19496-2013. Meat and meat products.The method of histological investigation. Moscow: Standartinform;2014. 10 p.According to sensory analysis, wheat and potatofibres showed the most rational properties for use inmeat production. In addition, potato fibres had anincreased hydrating and swelling ability, contributing tothe formation of three-dimensional food products.This information is relevant to selecting dietary fibrefor further use in the production of various foods.The histological structure of SuperCel wheatand potato fibres of the WF 600 and KF 500 grades,respectively, is shown in Fig. 2.The analysis (Fig. 2) showed that wheat fibres hada three-dimensional structure characteristic of planttissues. Under the light microscope, we could clearlysee the surface of the fibres: the core, the periphery,and threads with varying degrees of deformation.Observation at different sharpening levels revealed acertain spatial network formed by the wheat fibres.Potato fibres had a relatively uniform compositionwith differentiated fragments of cellular structures,round-shaped starch grains of various diameters, andoptical density fluctuations over the entire structure ofthe preparation.In order to optimise the processes, we then studiedthe rheological properties of model systems (dietaryfibre-water), using the ratios recommended by themanufacturer.The analysis of the graphs (Fig. 3) showed thatWF 600 SuperCel wheat fibres had a more complexrheological behaviour at the initial stage of testing.In our opinion, this was due to the difficulty in rotorspinning at that stage caused by their complex 3Dstructure and, presumably, adhesion. Initially, the shearrate gradient was 2.7–5.5 s–1.Table 1 Technological properties of SuperCel fibresType of fibre Grade Average fibrelength, μmAverage fibrethickness, μmDegree ofhydrationWater bindingcapacity, g water/gFat absorption,g fat/gBulk weight,g/dm3Insoluble:wheatWF 200 R 250 25 1:8 8.3 6.9 72−98WF 300 R 350 25 1:9 9.2 7.3 58−80WF 400 R 500 25 1:10 10.5 11 37.5−62.5WF 600 R 80 20 1:5 4.2-5.5 3.7 200−240Semi-soluble:potatoKF 200 200-350 − 1:8 15 − 250−400KF 500 400−1000 − 1:8 15 − 80−250Soluble:psylliumP95 250 − 1:25 20 − 170(а) (б)Figure 2 Histological structure of SuperCel dietary fibres:(a) WF 600 wheat; (b) KF 500 potato (40 magnification)1101001000100002.77 5.54 11.07 22.15 44.388.59177.2924164.4534.1316.579.8384.7412.231144.682.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-1ηef.0 1 2 3 4 5TasteSmellTexture391Titov E.I. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 387–395Further stages were carried out in the range from4.2 to 177.2 s–1. In those cases, KF 500 SuperCel potatofibres had a more effective viscosity, expressed inlogarithmic coordinates (from 1 to 10000 Pa·s).The rheograms above can be correlated with typicalcurves for viscous flow materials that are liquefiedby shear. A significant part of food materials (applepulp, puree-like products, mayonnaise, dairy products,pumping pickles, etc.) are non-Newtonian. It meansthat their rheological behaviour depends on the sheargradient, and the graph may feature a yield strength.Differentiated on the rheograms, which can be builtin logarithmic coordinates, are Newtonian viscosityregions (low shear values), a zone of reduced viscosityas a power function (structural dispersion), and aNewtonian region of high shear [31, 32]. These data areimportant for predicting the course of production cyclesand for food quality control.The data shown in Fig. 3 suggest that these fibrescan be attributed to colloidal structures that aremostly hydrophilic and are able to swell and bind foodmaterials. In addition, due to increased hydration andmicelle formation, they form more stable and uniformfood masses that can be easily introduced into theformulations of meat products.Based on the results, we can assume that theKF 500 SuperCel potato fibres correspond to suchmodified cellulose additives as methyl cellulose andcarboxymethyl cellulose in terms of rheologicalproperties and consistency. It means that they canexhibit pseudoplastic and non-thixotropic flowproperties. Thus, these potato fibres can form clusters ofpolymer chains and 3D structures.Consequently, these data can help us rationalisethe processes of mixing, moulding, pressing, andheat treatment, as well as prevent syneresis, layering,and other processes. More stable functional andtechnological properties can also be used to optimisethe stages of packaging and storing semi-finished andfinished products (for example, convenience meatproducts, snacks, etc.).In connection with the above, of great interest is theuse of dietary fibres in the production of various typesof meat products, for example, cooked sausages, mincedproducts, pastes, pork products, etc. [33−37]. Takinginto account consumers’ desire to buy inexpensive highqualitymeat products, manufacturers are developingnew ways of restructuring meat.Therefore, our further studies aimed to identifypossible uses of dietary fibre in the meat technology,particularly in the development of restructured productsfrom poultry meat.Pieces of poultry meat, both red and white, wereminced in a meat mincer with a hole diameter of16−25 mm to be used as a meat raw material. Salt andgranulated sugar were used as curing ingredients.Meat raw materials were massaged on a vibratingmassager at a rotation speed of 10 min–1 for 40 min.The amount of brine was 20% of the initial weight ofthe material. Further process stages included brining,forming, cooking at 80°C until the product reached72 ± 2°C in the centre, and air cooling at 4 ± 2°C untilthe finished product was 8°C in the centre.The composition of brines is shown in Table 2.Sensory evaluation is one of the determining factorsin assessing the quality of food products (Fig. 4).As can be seen in Fig. 4, the test sample containingdietary fibres of the selected grades was just as good asthe control product in its sensory parameters. The testFigure 3 Rheograms for various types of dietary fibre: bluefor WF 600 wheat; red for KF 500 potato1101001000100002.77 5.54 11.07 22.15 44.388.59177.2924164.4534.1316.579.8384.7412.231144.682.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-1ηef.0 1 2 3 4 5TasteColourSmellTextureControl Опыт20120220320420Control Test53.71 54.18413.31 417.89Shear stress, kPa Cutting work, J/m2Table 2 Brine compositionIngredients Ingredient amount,kg per 100 L of brineControl TestWater 89.5 84.5Granulated sugar 0.5 0.5Salt 10.0 10.0SuperCel WF 600 wheat fibres − 1.0Fucus − 3.5SuperCel KF 500 potato fibres − 0.5Total: 100 100 Figure 4 Sensory evaluation of restructured poultry products5.54 11.07 22.15 44.388.59177.264.4534.1316.579.8384.7412.23182.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-10 1 2 3 4 5TasteColourSmellTextureControl ОпытControl Test53.71 54.18413.31 417.891101001000100002.77 5.54 11.07 22.15 44.388.59177.2924164.4534.1316.579.8384.7412.231144.682.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-1ηef.0 1 2 3 4 5TasteColourSmellTextureControl Опыт20120220320420Control Test53.71 54.18413.31 417.89Shear stress, kPa Cutting work, J/m21101001000100002.77 5.54 11.07 22.15 44.388.59177.2924164.4534.1316.579.8384.7412.231144.682.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-10 1 2 3 4 5TasteColourSmellTextureControl Опыт20120220320420Control Test53.71 54.18413.31 417.89Shear stress, kPa Cutting work, J/m25.54 11.07 22.15 44.388.59177.264.4534.1316.579.8384.7412.231144.682.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-10 1 2 3 4 5TasteColourSmellTextureControl Опыт53.71 54.18413.31 417.89392Titov E.I. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 387–395sample’s consistency received the highest rating from thepanelists.Microbiological tests and safety indicators analysiscan be used to establish the degree of product safety.Safe products do not contain pathogenic or conditionallypathogenic microorganisms and do not exceed themaximum permissible concentration of toxic elements,pesticides, mycotoxins, antibiotics, hormones, andradionuclides. We found that the test sample met therequirements of the Methodological Guidelines andTechnical Regulations of the Customs Union 034and 021 (Table 3).With regard to strength characteristics, we concludedthat introducing dietary fibre into the brine formassaging the test sample contributed to an increase inshear stress and cutting work, compared to the control(Fig. 5). It improved the consistency of the finishedproduct and its sensory characteristics (Fig. 4).The meat products containing dietary fibre had alower mass loss during heat treatment and higher waterholdingcapacity and yield, compared to the controlsample (Table 4).Table 5 shows the influence of dietary fibre on theindicators of biological and energy value of the meatproducts.The total energy value of the test sample decreasedby 8% due to a reduced fat content. We believe thatthe decrease in the mass fraction of fat was caused bythe formation of a capsule of dietary fibre around fatdroplets, which prevented the extraction of the lipidcomponent during its determination.The digestibility of in vitro proteins in the testsample was 10% lower than in the control. This was dueto the presence of ballast substances in the restructuredpoultry product that are not digested by enzymes of thegastrointestinal tract.Table 3 Safety indicators for restructured poultry products containing dietary fibresIndicator Requirements according to ResultsTechnical Regulationsof the Customs Union 034Technical Regulationsof the Customs Union 021MethodologicalGuidelinesMicrobiological indicatorsColiforms not allowed in 0.1 g not detectedSulphite-reducing clostridia not allowed in 0.01 g not detectedS. aureus not allowed in 1 g not detectedE. coli not allowed in 1 g not detectedPathogenic, incl. salmonella not allowed in 25 g not detectedQMA&OAMO, CFU/g max 1 × 103 not detectedL.monocytogenes not allowed in 25 g not detectedContent of toxic elements, mg/kg, maxLead mass fraction 0.5 < 0.001Arsenic mass fraction 0.1 < 0.001Cadmium mass fraction 0.05 < 0.0001Mercury mass fraction 0.05 < 0.0001Figure 5 Structural and mechanical properties of restructuredpoultry products1101001000100002.77 5.54 11.07 22.15 44.388.59177.2924164.4534.1316.579.8384.7412.231144.682.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-1ηef.0 1 2 3 4 5TasteColourSmellTextureControl Опыт20120220320420Control Test53.71 54.18413.31 417.89Shear stress, kPa Cutting work, J/m21101001000100002.77 5.54 11.07 22.15 44.388.59177.2924164.4534.1316.579.8384.7412.231144.682.8749.1429.5715.64.4662.819Rotor shear rate gradient, s-1ηef.0 1 2 3 4 5TasteColourSmellTextureControl Опыт20120220320420Control Test53.71 54.18413.31 417.89Shear stress, kPa Cutting work, J/m2Table 4 Functional and technological properties ofrestructured poultry productsSamples Yield,%Thermalloss, %Moisture, % Water-holdingcapacity, % tototal moistureControl 83.8 14.7 ± 0.8 72.5 ± 2.3 79.1 ± 2.1Test 87.3 9.3 ± 0.7 74.1 ± 2.4 87.2 ± 2.0Table 5 Nutritional indicators of restructured poultry productsIndicators Control TestMoisture mass fraction, % 66.80 ± 2.32 68.10 ± 2.73Protein mass fraction, % 16.77 ± 0.49 16.70 ± 0.56Fat mass fraction, % 13.40 ± 0.37 11.30 ± 0.31Ash mass fraction, % 3.03 ± 0.09 3.40 ± 0.10Carbohydrates massfraction, %Traces 0.30 ± 0.02Energy value, kcal/100 gof product188.40 ± 5.24 170.00 ± 4.86Digestibility of in vitroproteins,mg tyrosine/100 g protein:by pepsin 4.84 ± 0.09 4.63 ± 0.09by trypsin 9.92 ± 0.29 9.83 ± 0.29Total: 14.76 ± 0.43 14.46 ± 0.43393Titov E.I. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 387–395Figure 6 shows the results of microstructural studiesto assess the uniformity of distribution of the curingmixture in the finished products.The analysis of histological preparations did notreveal any significant differences between the controland the test samples. Their microstructure showedthe presence of exclusively muscle tissue with afew fragments of adipose and connective tissue thatmake up the muscular skeleton. We also found somecomponents of endomysium, coarse fibrous interlayersof perimysium, and a small amount of fat cells.Noteworthily, cell membranes of muscle and connectivetissue retained their integrity outside the fragmentationzone. A distinctive feature of the test sample’smicrostructure was a local presence of dietary fibrefragments and an increased amount of muscle tissuedecomposition products.CONCLUSIONWe established specific structural characteristics,properties, and rheological behaviour of various dietaryfibres. We found that potato fibres demonstratedgreater uniformity in texture and rheology, comparedto wheat fibres.Wheat fibres had a clear phase structure (fibre/water),whereas potato fibres showed significant hydrophilic andstructuring properties, attributing them to colloidal fibres.Comprehensive studies revealed that a combined useof wheat and potato fibres in massage brines contributedto the production of restructured poultry products withgood functional and technological properties. It alsoincreased meat succulence and prevented liquefaction,syneresis, volume loss, etc.Using potato and wheat fibres can help producersto expand the range of meat products in line withthe concepts of rational and healthy nutrition, i.e.preventative products.Our experimental material can become a basis forfurther research aiming to create combined dietaryfibre complexes that can be used in the production ofbiologically active dietary supplements and specialisedmeat products.CONFLICT OF INTERESTThe authors declare no conflict of interest.