The study objects were the Republic of Kazakhstan selection apple sorts: “Baiterek”, “Sarkyt” and “Saya”, also pear sorts: “Syilyk”, “Zhazdyk” and “Nagima”. Study of the process of moisture evaporation within vacuum drying of the fruits has essential value in the nutritional value saving. Basically, the product evaporative capacity is characterized by the evaporation resistance coefficient ‒ µ. Also during moisture removal, thermodynamic state of moisture changes that is described by water activity indicator ‒ aw. Experimental determination of these parameters allows for the analyzing moisture evaporation during vacuum drying process. Studies have established the following evaporation resistance coefficients: µ=2.03±0.07 for apple sorts and µ=2.3±0.05 for pear sorts. Either water activity decreases from 1.0 to 0.62±0.01 for apple sorts and from 1.0 to 0.65±0.04 for pear sorts. Two drying periods are discovered. The first drying period: 5.45–6.10 h for apple sorts; and 6.12–6.25 h. for pear sorts. The second drying period duration: 4.15–3.50 h for apple sorts; and 4.35–4.48 h for pear sorts. The critical humidity value: 27.1±2.1 % for apple sorts; and 30.1±2.5 % for pear sorts. Comparative analysis of calculated and experimental data shows maximum deviations 22.5 % for apple sorts and 23 % for pear sorts. The proposed equation for the calculating a moisture evaporation rate, considering the product properties and the hygroscopic parameters of air, can be used in practice to study the moisture evaporation dynamics from the product surface. The study results allow for the selecting an optimal mode for vacuum drying of apples and pears sorts in order to safe nutritional value and to produce biologically active additives for the food industry

The fermented mare's milk -Koumiss and camel's milk -Shubat are traditional national dairy products in Kazakh cuisine. Concentrated dairy products in the form of clots have a quantity content of useful chemical compounds. In the presented study it was investigated the desorption isotherms of the koumiss and shubat clots enriched by vegetative additives. It was established, that the interface between weakly and strongly bound moisture can be: for the koumiss clots enriched by juices: of a carrot а w =0,56, u х = 0.69 kg/kg; of a pumpkin а w =0,58, u х = 0,80 kg/kg; of a beet а w =0,59, u х = 0,81 kg/kg; as well as for shubat clot, enriched by juices: of a carrot а w =0,62, u х =0,73 kg/kg; of a pumpkin а w =0,65, u х = 0,67 kg/kg and of a beet а w =0,63, u х =0.66 kg/kg.

No abstract

As the drying zone deepens, outer surface layer of the product does not have time to be moistened, due to a small amount of moisture coming from the inside. It becomes dry, its temperature rises. The intensity of moisture transfer from the inner layers of the product depends on many parameters, including a moisture diffusion coefficient. The study aim is to create a methodology for determining the moisture diffusion coefficient within vacuum drying of fruits, by taking into account cracks, channels and capillaries formed in the dry layer of the product through the resistance coefficient to evaporation. The work essence consists in the determining of the moisture diffusion coefficient as a driving force, a difference between water activity and air humidity, by considering the resistance coefficient to evaporation, characterizing the effect of hydrodynamic resistance of the dried dry layer of the product. This approach was used to determine the moisture diffusion coefficient during vacuum drying of the Baiterek apple sort and the Zhazdyk pear sort of Kazakhstani selection. It was established that in the first period of drying the moisture diffusion coefficient decreases on average from 24,4∙10‒7 m2/s to 13,2∙10‒7 m2/s. The critical humidity for pear is 37.4 %, and for apple 35.1 %. As result of the formation of dry layer on the surface and subsequent layers, the moisture diffusion coefficient gradually decreases. In the second drying period, the moisture diffusion coefficient decreases from 5,42∙10-8 m2/s to 2,12∙10‒8 m2/s. The work practical significance is related with the application of the obtained results in the determination of the optimal drying regime with maximum preservation of the product original quality. The proposed methodology can be used in the practice to study the moisture diffusion coefficient within vacuum drying of fruits, by considering the product properties and the hygroscopic parameters of the drying matter

This work is aimed at developing a procedure for controlling the rheological properties of wheat dough during its kneading based on a parametric model. Dough kneading is the most important technological operation in the production of bakery products. When organoleptically assessing the consistency of the dough, it is difficult to accurately determine its rheological properties while maintaining the mass of water and its intensity at a constant level of the mass of the kneaded dough, considering the processed flour. However, our proposed procedure can solve these problems. According to the results obtained, it was experimentally found that the nature of changes in the specific intensity of dough kneading, which contributed to obtaining the best quality bread at a kneading body rotational speed of 150 rpm, is optimal. The dough kneading intensity leads to a reduction in the kneading time from 290 s at nm=60 rpm to 90 s at nm=240 rpm. The optimal duration of dough kneading  was 124 s. The results make it possible to determine the water absorption capacity of flour in the production of bakery products, considering its baking properties and dough recipe, and, accordingly, the optimal moisture content of the dough

Relevance. Fruits and vegetables are an excellent source of substances with antioxidant and healthy properties. Such substances include polyphenols, carotenoids and triterpenoids. Phenolic compounds have strong antioxidant, anti-inflammatory, antiviral and anti-carcinogenic properties. Pear is the main fruit crop of regions with mild climate and have growing cultivation scales. Pear flavonoids contribute to the coloring of fruits, protect them against pathogens and are healthy ingredients of fruits. The purpose of the research is to analyze the content of flavonoids in pears of Kazakhstan selection.Methods. The methods used in the study are as follows: determining solids content (the found value is expressed in units of the mass fraction of sucrose in an aqueous solution of sucrose, which under given conditions has the same refractive index as the analyzed solution, in %) titratable acidity (determination of the mass concentration of titratable acids in terms of malic, tartaric or citric acids (μg/mL) was carried out using potentiometric titration with sodium hydroxide solution to pH = 8.1), total sugars (the permanganate method is based on the ability of sugar carbonyl groups to reduce copper (II) oxide to copper (I) oxide in an alkaline medium), sugar-acid index, ascorbic acid (vitamin C) content, total phenolic compounds content, total flavonoids content.Results. The comparison analyses shows Syilyk and Zhazdyk varieties have the highest values of studied traits,. Specifically, physico-chemical indicators: solids content, total sugars and titratable acidity. Also the best indicators are shown in biological active compounds: sugar-acid index, ascorbic acid (vitamin C) content, total phenolic content and total flavonoids content. The polyphenols content in all pear varieties have high values in the range 107–124 μg/mL. Extracts of Syilyk and Zhazdyk pears have highest values of biologically active substances, and might be recommended for the development of technology in order to obtain concentrates and to enrich the compositions of the food products.

Studies have established that various drying periods are observed during the drying process: for example, for apple varieties, the first drying period is 5.45...6.10 hours, and for pear varieties 6.12 ...6.25 hours. The duration of the second drying period for apple varieties is 4.15...3.50 hours, and for pear varieties 4.35...4.48 hours. The analysis of the drying curve showed that the boundary between the periods of constant and falling land velocity, i.e. the critical humidity for apple varieties is on average 27 ± 2.1%, and for pear 30.1 ± 2.5%. An analysis of the kinetics of moisture evaporation shows that in an apple during the first four hours of drying, on average, 2.71 g evaporates, and for the next two hours it decreases monotonically to 2.31 g. The same picture of moisture evaporation dynamics is also observed for pears: for the first four hours, on average, 3.41 g evaporates, and for the next two hours, the evaporation dynamics decreases to 2.78 g. Studies have established that the coefficient of evaporation resistance for apple varieties: Baiterek, Sarkyt and Saya is µ = 2.03 ± 0.07, for pear varieties: Sylyk, Zhazdyk and Nagima is µ = 2.3± 0.05.

На сегодняшний день является актуальным сохранить качество производства биологически активных добавок, где необходимо уделять внимание биологическим процессам, которые протекают, в плодовом и ягодном сырье, например, изменение активности ферментов аскорбиноксидазы, пероксидазы и полифенолоксидазы. Такие окислительно восстановительные ферменты могут вызвать потемнения при термической обработке и хранении, что может привести к низкому качеству конечного продукта. Одним из способов инактивировать ферменты в растительном сырье является бланширование. В последнее время в мире изучаются новые методы бланширования растительного сырья, так как традиционные методы бланширования увеличивают время обработки сырья, а также не полностью снижают активность ферментов. В данной статье было исследовано влияние тепловой обработки методом нагрева сверхвысокочастотного излучения на изменение активности ферментов аскорбиноксидазы, пероксидазы и полифенолоксидазы в плодах яблок и груш отечественной селекции. В ходе работы было выявлено, что при бланшировании паром необходимо больше времени для инактивации ферментов, тогда как при использовании тепловой обработки в сверхвысокочастотном излучении инактивация ферментов наступает уже к 4 минуте, а на 5 минуте инактивируется полностью. Исследования проводились на базе Южно-Казахстанского университета им. М.Ауэзова в летне-осенний период.