Hydrolysate of ovalbumin: production and evaluation of the functional properties of peptides

Chicken eggs proteins and their derivatives, like protein hydrolysates, peptides and amino acids, possess high nutritional value and provide a wide range of biological activity. They serve as sources for development of functional ingredients that draw the attention of specialists in the food production and biomedical industries, as well as the livestock feed industry. Enzymatic hydrolysis of proteins is a popular process for obtaining bioactive peptides with multifunctional properties. The purpose of this study is to obtain a hydrolysate of ovalbumin with a high degree of hydrolysis and to determine its functional and technological parameters. The research presents a two-stage scheme of ovalbumin hydrolysis with the help of pepsin and trypsin which provide high degree of hydrolysis (82–83%). The fractional composition of the hydrolysate is determined. The fractional composition is represented by three main fractions (high, medium and low molecular weight). The summarized antioxidant activity (SAA) of the hydrolysate is considered within the dynamics of the hydrolysis process. The highest SAA value was noted after 2 hours, and it amounted to 170.23 mg/l; at the end of hydrolysis the SAA value was equal to 114.31 mg/l. When analyzing the SAA, it was found that the main contribution to the summarized antioxidant activity of the ovalbumin hydrolysate is made by peptides of the medium molecular fraction. The microfiltration process, used in the research, made it possible to separate high-molecular compounds, which led to an increase in the SAA of the hydrolysate to 189.9 mg/l. The main functional and technological parameters of the hydrolysate are determined in this research. The comprehensive study of the biological activity and functional characteristics of egg protein hydrolysates and their peptides provides a theoretical basis for expanding the range of functional ingredients obtained from food proteins and for replenishing the range of functional foods.Chicken eggs proteins and their derivatives, like protein hydrolysates, peptides and amino acids, possess high nutritional value and provide a wide range of biological activity. They serve as sources for development of functional ingredients that draw the attention of specialists in the food production and biomedical industries, as well as the livestock feed industry. Enzymatic hydrolysis of proteins is a popular process for obtaining bioactive peptides with multifunctional properties. The purpose of this study is to obtain a hydrolysate of ovalbumin with a high degree of hydrolysis and to determine its functional and technological parameters. The research presents a two-stage scheme of ovalbumin hydrolysis with the help of pepsin and trypsin which provide high degree of hydrolysis (82–83%). The fractional composition of the hydrolysate is determined. The fractional composition is represented by three main fractions (high, medium and low molecular weight). The summarized antioxidant activity (SAA) of the hydrolysate is considered within the dynamics of the hydrolysis process. The highest SAA value was noted after 2 hours, and it amounted to 170.23 mg/l; at the end of hydrolysis the SAA value was equal to 114.31 mg/l. When analyzing the SAA, it was found that the main contribution to the summarized antioxidant activity of the ovalbumin hydrolysate is made by peptides of the medium molecular fraction. The microfiltration process, used in the research, made it possible to separate high-molecular compounds, which led to an increase in the SAA of the hydrolysate to 189.9 mg/l. The main functional and technological parameters of the hydrolysate are determined in this research. The comprehensive study of the biological activity and functional characteristics of egg protein hydrolysates and their peptides provides a theoretical basis for expanding the range of functional ingredients obtained from food proteins and for replenishing the range of functional foods

Optimization of protein-lipid comlex by its fatty acid and vitamin composition

The polycomponent protein-lipid compositions are traditionally used in minced meat products to regulate nutritional value, functional, technological and organoleptic characteristics of the finished product. The present article presents the results of research aimed to creation of antioxidant-enriched protein-lipid complex (PLC) with the optimal ratio ω3: ω6 of PUFA. The ratio of lipid component was optimized by linear programming method, where the recommended ratio of ω-6: ω-3 of PUFA as 10: 1 was used as term of limitation. In result of calculations the fatty component was obtained by blending of rendered beef fat with soybean oil and sunflower oil in the following ratio: rendered beef fat — 73%, sunflower oil — 15%, soybean oil — 12%. After that the PLC formulation was optimized by research of influence of the introduced protein complex in amount from 4% to 10% and the fatty component in amount from 40% to 43% on index of shear stress of the PLC. The introduced amount of protein, fat and water is taken in ratio 1:(4–7):(4–7) commonly used in the meat processing industry to form the functional and technological characteristics of the minced meat. In result of experiments the following PLC formulation was adopted, which provides the necessary stable consistency of the mixture: protein complex — 9%, fatty component — 42%, water — 49%. To enrich meat products with vitamins and antioxidants it is proposed to include into PLC an extract obtained with microwave field 800 W from the Daurian rosehips which grows in the Far East region. The obtained PLC has a high water-retaining capacity; it remains stable while heating and it can be stored for five days without any visible signs of deterioration, as the peroxide value remains within the permissible limits. PLC features optimal ratio of ω-6: ω-3 of PUFA, equal to 10:1, and a high value of the total antioxidants equal to 5.4 mg/g.

Effect of blueberry (vaccínium myrtíllus) leaves extract, obtained by microwave heating on the dynamics of animal fat oxidation processes

The potential of antioxidant properties of blueberry leaves extract (vaccínium myrtíllus) that grows in the Trans-Baikal region has been studied in this work. In order to increase the efficiency of extraction of biologically active substances with antioxidant properties, this extract was obtained with the help of microwave field. The optimal parameters for the extraction of active substances from the blueberry leaves with the help of electromagnetic microwave field have been defined. The influence of the power of the electromagnetic field and the duration of the process of blueberry leaves extraction on the efficiency of extraction of biologically active polyphenolic substances has been studied. The following parameters of the technology for blueberry leaves extraction were obtained: extraction with a water-alcohol solution with a concentration of 40% in the ratio of raw materials to extractant as 1 to 5, with duration of stirring as long as 30 minutes, then the application of an electromagnetic field of microwave heating with a power of 850W for 8–10 minutes long. Blueberry leaves extract is a clear liquid with a high content of polyphenols, of rich brown color, tart taste, without bitterness. The antioxidant potential of the obtained extract has been studied. To do this, the extract has been added into the finely ground animal fat and left for storage in a closed dark container. During storage, the dynamics of the peroxide number has been measured, as this value characterizes the degree of lipid oxidation. It has been found that blueberry leaves extract inhibits the process of animal fat oxidation due to the action of biologically active substances that feature antioxidant properties

A method development for improving the stability of vegetable polyphenol complexes for semi-finished minced meat products with antioxidant effect

Polyphenolic vegetable complexes are active antioxidants and play an important role in the processes of free radicals quenching in the human body. The aim of the work was to develop an immobilization method as a way for improving the stability of polyphenols in dried cowberry squeezing extract (DCSE) and to develop semi-finished minced meat products with antioxidant effect without changing their nutritional value. Experiments were carried out to study the nutritional value of DCSE. The presence of a large number of polyphenolic compounds in DCSE and a high radical-binding ability of the extract were revealed. Based on the mathematical planning method, an offal paste composition was obtained, which was used to obtain pellets, and the formulation of semi-finished minced meat products with pellets was optimized. It was established that preliminary immobilization of DCSE on offal pellets components allows to increase the level of total antioxidant content in the minced meat. Subsequent heat treatment of semi-finished minced meat products produced from such minced meat showed an increase in stability and, thus, bioavailability of antioxidants and the possibility of obtaining a finished product with antioxidant effect. The antioxidant effect of cowberry squeezing extract in the meat system is proved: accumulation of lipid oxidative decomposition products in the meat system during storage of frozen semi-finished minced meat products was inhibited to a greater extent when using offal pellets with immobilized compounds of cowberry squeezing extract. This work was carried out as part of the State Assignment of the Ministry of Education and Science of the Russian Federation No. 19.5486.2017/BCh and the «Young Scientists of ESSTU‑2019» grant

ПИЩЕВАЯ ЦЕННОСТЬ ИННОВАЦИОННОГО СЫРОКОПЧЕНОГО ПРОДУКТА ИЗ СВИНИНЫ

Abstract The article presents the results of the study on nutritional value of the uncooked smoked pork product with the complex brine. It was found that the use of the starter cultures on the basis of Lactobacillus brevis and Lactobacillus fermentum in an amount of 5% by weight of the raw materials and the aqueous extract of dog-rose hips (Rosa Davurica) in an amount of 0.5% by weight of the raw materials, as recipe ingredients of the brine, allows reducing the duration of the drying process by 24 hours and the salting process also by 24 hours.It was found that the product meets the requirements of the standard for this type of products by the content of protein (13.2%) and fat (27.8%). The uncooked smoked pork loin, which was made using starter cultures on the basis of Lactobacillus brevis and Lactobacillus fermentum and the aqueous extract of dog-rose hips, is close to the recommended ratio of PUFAs : MUFAs : SFAs (10:60:30). The authors also noted that the presence of ascorbic acid in the extract led to a significant decrease in the residual amount of sodium nitrite by almost three times in the innovative smoked pork product, which increased its food safety.The results of the study showed that addition of the starter cultures L. brevis and L. fermentum and the extract of dog-rose hips (Rosa Davurica) to the brine during salting had a positive effect on the formation of the sensory characteristics of the pork loin: taste, aroma, color and its structural and mechanical properties. The product had the more monolithic, firm texture and rich color. The research on the quantitative detection of viable cells of L. brevis and L. fermentum in the uncooked smoked pork loin «Pikantnaya» was also done in this work. It was found that on the 25th day of storage, the total number of viable cells in the loin was 1*107 CFU/g, which corresponded to the requirements for the probiotic products.Аннотация В статье представлены результаты исследования пищевой ценности сырокопченого изделия из свинины с использованием сложного рассола. Выявлено, что использование в составе рассола дополнительных рецептурных ингредиентов – комбинированной закваски на основе стартовых культур Lactobacillus brevis и Lactobacillus fermentum в количестве 5% к массе сырья и водного настоя плодов шиповника Даурского (Rosa Davurica) в количестве 0,5% к массе сырья позволило сократить длительность таких процессов производства корейки, как посол (выдержка в заливочном рассоле) на 24 ч и сушку на 24 ч.Выявлено, что по содержанию белка (13,2%) и жира (27,8%) готовый продукт соответствует требованиям стандарта, предъявляемым к данному виду продукта. По соотношению ПНЖК:МНЖК:НЖК корейка «Пикантная» приближается к рекомендуемым нормам 10:60:30. Отмечено, что присутствие в настое аскорбиновой кислоты приводит к снижению остаточного количества нитрита натрия почти в три раза в инновационном сырокопченом продукте из свинины, что повышает его пищевую безопасность.Доказано, что добавление стартовых культур L. brevis и L. fermentum и настоя плодов шиповника Даурского в посолочный рассол оказывает положительное влияние на формирование высоких органолептических показателей корейки: вкуса, аромата, цвета и структурно-механических характеристик. Готовый продукт имеет монолитную, плотную консистенцию и насыщенный цвет. В работе также были проведены исследования по количественному учету жизнеспособных клеток L. brevis и L. fermentum в корейке «Пикантная», установлено, что количество жизнеспособных клеток в корейке на 25 сутки хранения (1*107 КОЕ/г), что соответствует требуемым нормам, предъявляемым к пробиотическим продуктам

Comparative analysis of the rate of aging in men and women in the 20-30 years age group

The purpose of study is to establish the possibility of predicting the rate of aging in persons aged 20-30 years.Цель исследования - установить возможность прогнозирования темпа старения людей в возрасте 20-30 лет

Modern agglutinated foraminifera from the Hovgård ridge, fram strait, west of Spitsbergen: Evidence for a deep bottom current

Deep-water agglutinated foraminifera on the crest of the Hovgârd Ridge, west of Spitsbergen, consist mostly of large tubular astrorhizids. At a boxcore station collected from the crest of Hovgârd Ridge at a water depth of 1169 m, the sediment surface was covered with patches of large (1 mm diameter) tubular forms, belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubutar species consisted mainly of opportunistic forms, such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms point to the presence of deep currents at this locality that are strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation in relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge, indicative of winnowing in a south-easterly direction

Спонтанный пневмомедиастинум, пневмоторакс, пневмоперитонеум и эмфизема мягких тканей как осложнения у пациентов с COVID-19, серия клинических наблюдений

Spontaneous pneumomediastinum, pneumothorax, pneumoperitoneum, and soft tissue emphysema have been recently described in several sources as possible complications in patients with severe COVID-19 and lung damage. This clinical case is dedicated to demonstrarte the development of these lesions in 3 male patients with comorbid conditions. The putative pathophysiological mechanism of these complications is air leakage due to extensive diffuse alveolar damage followed by rupture of the alveoli. All presented patients had a favorable outcome of the disease without lethal cases, their laboratory data and clinical dynamics were described.It should be noted that such conditions are not rare complications of COVID-19, and are observed mainly in male patients with severe form of the disease and the presence of comorbid conditions. Such complications are associated with long hospitalization and a severe prognosis. In some cases, with a mild course of the disease and positive dynamics in a decrease of the percentage of pulmonary lesions, the outcome is favorable, not requiring additional invasive interventions.Спонтанный пневмомедиастинум, пневмоторакс, пневмоперитонеум и эмфизема мягких тканей описаны в нескольких источниках как возможные осложнения у пациентов с тяжелой формой течения COVID-19 и сопутствующим поражением легких. Данное наблюдение направлено на то, чтобы проследить динамику развития этих поражений у 3 пациентов мужского пола с наличием коморбидных состояний. Предполагаемым патофизиологическим механизмом развития данных осложнений является утечка воздуха из-за обширного диффузного альвеолярного повреждения с последующим разрывом альвеол. У всех представленных пациентов исход заболевания был благоприятен, без летальных случаев, были приведены их лабораторные данные и клиническая динамика, а также динамика изменений поражения легочной ткани.Следует отметить, что подобные состояния не являются редкими осложнениями при COVID-19 и наблюдаются в основном у пациентов мужского пола с тяжелой формой заболевания и наличием коморбидных состояний, ассоциированы с длительной госпитализацией и тяжелым прогнозом. В некоторых случаях при более легкой форме течения заболевания и положительной динамике в виде уменьшения процента поражения легких исход благоприятен и не требует дополнительных инвазивных вмешательств

Neonates’ responses to repeated exposure to a still face

The main aims of the study were to examine whether human neonates' responses to communication disturbance modelled by the still-face paradigm were stable and whether their responses were affected by their previous experience with the still-face paradigm.The still face procedure, as a laboratory model of interpersonal stress, was administered repeatedly, twice, to 84 neonates (0 to 4 day olds), with a delay of an average of 1.25 day.Frame-by-frame analysis of the frequency and duration of gaze, distressed face, crying, sleeping and sucking behaviours showed that the procedure was stressful to them both times, that is, the still face effect was stable after repeated administration and newborns consistently responded to such nonverbal violation of communication. They averted their gaze, showed distress and cried more during the still-face phase in both the first and the second administration. They also showed a carry-over effect in that they continued to avert their gaze and displayed increased distress and crying in the first reunion period, but their gaze behaviour changed with experience, in the second administration. While in the first administration the babies continued averting their gaze even after the stressful still-face phase was over, this carry-over effect disappeared in the second administration, and the babies significantly increased their gaze following the still-face phase.After excluding explanations of fatigue, habituation and random effects, a self-other regulatory model is discussed as a possible explanation for this pattern