Content
4 . 2019
Reviews

Lipoic acid: physiological role and prospects for clinical application

Abstract

The new aspects of clinical nutrition at Wilson disease: actuality and perspectives

Abstract

Wilson disease is hereditary disorder of copper metabolism, based on defect of cooper excretion, which leads to accumulation of cooper in the liver and brain. This disease is one of the most difficult to diagnose. Without treatment disease brings to early disability and lethal outcome. In the article, domestic and foreign approaches to dietary management of Wilson disease have been compared. Diet is not recommended as sole therapy. The degree of restriction of the products containing copper now is discussed. According to the Russian clinical guidelines of diagnosis and treatment of Wilson disease exception of products, copper content in which exceeds 0.5 mg/100 g (liver, shellfish, nuts, cocoa products, mushrooms, bean and some grains) is recommended, while in EASL clinical guidelines there are no any information about restriction of the products containing copper. It is necessary to pay attention not only to cooper restriction, but also to qualitative components of diet. Protein is important part of nutrition under liver disease. According to ESPEN guidelines, the recommended protein intake at chronic hepatitis and cirrhosis is 1.2-1.5 g/kg/day. Dairy products and whey protein are good sources of protein, they almost do not contain cooper, therefore they can be used without restrictions at Wilson disease (in case of normal lactose and milk protein tolerance). The reduce of consumption of sugar, refined carbohydrates and trans fats is also recommended. Dietary recommendations must take into consideration the nutrition status of the patient (protein energy malnutrition, normal body weight, obesity) and degree of liver damage (chronic hepatitis, cirrhosis). It is necessary to develop individualization of diet, increasing efficiency of medicinal treatment of Wilson disease.

Physiology and biochemistry nutrition

A comparative evaluation of the effect of soy protein and its enzymatic hydrolysate on lipid metabolism in male Wistar rats with induced obesity

Abstract

Among various food proteins, soybean proteins have the greatest traditions of application for the dietary correction and prevention of lipid metabolism disorders and related complications.

Aim. In an in vivo experiment using male Wistar rats, the lipid-lowering properties of soy protein and its enzymatic hydrolysate were tested to evaluate their possible use as ingredients of specialized foods.

Material and methods. Animals were randomly divided into 3 groups: control group G1 and 2 experimental groups G2 and G3. The total duration of the experiment was 70 days. The animals of the control group G1 were fed with high-lipid semi-synthetic diet. Animals of the experimental groups G2 and G3 received the same high-fat semi-synthetic diet, but with a 50% replacement of casein with soy protein isolate (SPI) and enzymatic hydrolyzate of SPI (EHSPI), respectively. The blood glucose was measured once per 2 weeks. At the end of the experiment on the 71st day the level of glycated hemoglobin was determined in the blood; the levels of triglycerides, cholesterol, high density lipoproteins (HDL), low density lipoproteins (LDL) and the concentration of malon dialdehyde were determined in the serum.

Results and discussion. Starting from the 6th week of the experiment and prior to its completion, the average food intake of animals from the G3 group was significantly (р<0.05) lower compared to animals of the G1 control group. The food intake of animals of group G2 was significantly (р<0.05) reduced compared with this indicator for animals of group G1, starting from the week 8 of the experiment and prior to its completion. The monitoring of the body weight gain did not reveal significant differences between all groups of animals, despite differences in the food intake. Replacing casein in the diet by 50% with SPI had a pronounced antioxidant and cholesterol-lowering effect. The total cholesterol content (1.65±0.05 mmol/l) decreased significantly (р<0.05) due to a decrease in LDL (0.90±0.03 mmol/l), and malon dialdehyde level lowered (3.7±0.5 gmol/l, р<0.05) in the serum of group G2 rats compared with animals of the control group G1 (2.01±0.13 and 1.12±0.09 mmol/l; 5.1±0.4 gmol/l, respectively). Replacing casein by 50% with EHSPI in the diet of G3 rats was unfavorable, significantly (р<0.05) increasing the level of total cholesterol (2.76±0.16 mmol/l) and cholesterol in LDL (1.66±0.12 mmol/l) in blood of these animals compared with animals of both comparison groups G1 and G2. Conclusion. A preclinical comparative study of the cholesterol-lowering and antioxidant properties of the SPI substantiates the prospect of its following clinical trials with the aim of including into the composition of specialized foods for prevention and diet therapy of the disorders of endogenous cholesterol homeostasis.

Impact of L-carnitine and phosphatidylcholine containing products on the proatherogenic metabolite TMAO production and gut microbiome changes in patients with coronary artery disease

Abstract

The aim of the study was to assess the impact of L-carnitine and phosphatidylcholine containing products on the production of the proatherogenic metabolite TMAO and gut microbiome changes in patients with coronary artery disease (CAD).

Material and methods. The study consisted of 2 parts. In the first part, a comparison was made between the diet of patients with CAD (n=29) and healthy volunteers (n=30) over the age of 50 with respect to the frequency of intake of L-carnitine and phosphatidylcholine containing products. All participants underwent blood sampling and stool tests to assess the concentration of TMAO and the composition of fecal microflora. The second part of the study was dedicated to assessing the correlation between TMAO blood concentration in patients with CAD (n=89) and the frequency of intake of L-carnitine and phosphatidylcholine containing products.

Results and discussion. Patients with CAD comparing to healthy people among the predecessor products of TMAO consumed red meat, dairy products more often, eggs and fish less often. TMAO concentration in patients with CAD was higher than in healthy volunteers (1036.4±748.2 vs 376.5±147.9 ng/ml, p=0.0001). Analysis of fecal microflora in patients with CAD revealed an increase number of bacteria from Verrucomicrobiaceae family (p<0.05) and Enterobacteriaceae family (p<0.05), of the Escherichia/Shigella genera (p<0.05), there was a trend to increased number of Ruminococcus (р=0.065), Clostridium XlV (b) genera (р=0.10). Correlation between TMAO concentration and frequency of red meat, eggs, and dairy products consumption was estimated in patients with CAD (r>0.525, р<0.05).

Conclusion. Patients with CAD consume more precursors of TMAO, have higher blood TMAO concentrations compared to healthy volunteers. Fecal microflora of patients with CAD contains a greater number of gut bacteria related to trimethylamine producers compared to healthy volunteers. Reducing the number of L-carnitine and phosphatidylcholine containing products in the diet of patients with CAD may affect the decrease in the proatherogenic metabolite TMAO concentration.

Hygiene of nutrition

Assessment of physical development and diet of primary school children in Smolensk

Abstract

The growth and development of children largely depends on the diet. Irrational and irregular nutrition can contribute to the development of nutritional-dependent diseases of children and adolescents, the formation of overweight and obesity.

The aim of the research - the assessment of physical development and diet of primary schoolchildren living in Smolensk.

Material and methods. 817 schoolchildren aged 7-10 have been surveyed, of whom 403 (49.3%) were girls and 414 (50.7%) were boys. In the process of the study, the length and body mass have been measured, body mass index (BMI) has been calculated. Assessment of the physical development of children has been carried out according to the standards of the World Health Organization (WHO) using the software product WHO AnthroPlus (2009). Z-score values for body weight for age, body length for age, and BMI for age have been calculated. In the process of the study, children were questioned. A questionnaire on the diagnosis of the lifestyle of children, developed by specialists from the University of Cologne, made it possible to evaluate the mode and structure of nutrition of schoolchildren.

Results and discussion. It has been revealed that the average values of mass-growth indicators of Smolensk primary schoolchildren were higher compared with the standard WHO population. Deviations of physical development in the studied sample of schoolchildren were more concerned with body weight than growth, while obesity in boys was detected significantly more often than in girls (11.9 vs 5.2%, χ2=10.465, p=0.002). It has been established that the majority of primary schoolchildren (84.8%) ate 3-5 times a day. 92.7% of schoolchildren have breakfast at home. In the school canteen, only 55.6% of schoolchildren ate regularly. In the interval between dinner and supper, the majority (96.8%) of the respondents had a snack, of which 43.7% used patties, cookies or sweets for snacking. Almost half of primary schoolchildren (45.4%) admitted that they had food intake just before bedtime. Moreover, boys did this significantly more often than girls (50.8 vs 41.0%, χ2=5.209, p=0.023).

Conclusion. In order to prevent the formation of overweight and obesity among primary schoolchildren, it is necessary to introduce a complex of preventive measures. Among them, there are rationalization of children’s nutrition in the family and school, optimization of the day regime and physical activity of children, psychological support for children with overweight and obesity, the introduction of modern educational and information technologies for the formation of a healthy lifestyle of children.

Frequency of determining markers of casein's inhability and gluten in children with disorders of autistic spectrum

Abstract

The most optimal approach to the problem of managing children with autism spectrum disorders (ASD) is a complex one that involves a pediatric gastroenterologist, a nutritionist, a neurologist, a psychiatrist. Currently, there are studies that confirm the effectiveness of diet in the correction of neuropsychiatric status and gastroenterological disorders in ASD. Evidence supporting the therapeutic value of diets is limited and inconclusive. Diet therapy should be used only if food allergy or gluten or casein intolerance is diagnosed.

Aim. To study the frequency of detection of markers of gluten and casein intolerance in children with ASD.

Material and methods. The study involved 51 children (39 boys and 12 girls) aged 3 to 15 years with a diagnosis of ASD. Among the study participants, 20 children used gluten-free diet and casein-free diet for more than 6 months. The material for the study was venous blood taken from the elbow vein in the morning on an empty stomach. Determination of specific IgG-antibodies to casein and gliadin, IgA-antibodies to deamidized gliadin peptides was carried out by enzyme immunoassay. The level of total IgA to exclude selective deficiency was also determined.

Results and discussion. Most children with ASD (795%) had increased levels of specific IgG antibodies to casein. The increase in IgG antigliadin antibodies was determined in 19.3% of children who do not follow a gluten-free diet, and antibodies to deamidized gliadin Ig peptides were not detected in any patient. Gluten intolerance in children with ASD is characterized by sensitivity to it and occurs in 40-50%.

Conclusion. According to the literature and the results of own studies, some children with ASD have gluten and casein intolerance. Before the appointment of diet therapy for children with ASD, it is necessary to conduct a survey to clarify the nature of intolerance and the choice of optimal tactics of diet therapy.

Nutrition of sportsmеn

The efficiency of branched chain aminoacids (BCAA) in the nutrition of combat sport athletes

Abstract

Balanced nutrition of athletes involves the usage of both ordinary products and complexes of functional food ingredients that contribute to improving the performance of athletes, strengthening the immune system. One of the main components of specialized foods that are widely used in sports’ nutrition and food supplements are branched chain aminoacids (BCAA): valine, leucine, isoleucine.

The aim of the work was to study the effect of the BCAA intake on the parameters of body composition and the immune status of combat sport athletes during the training period. Material and methods. The object of the study was 20 athletes (masters of sports and candidates for masters of sports in combat sports: sambo, judo) at the age of 17-18 years. Athletes were distributed into 2 groups. Athletes of the main group (n=10) for 4 weeks in addition to the main diet were supplemented with BCAA at a dosage of 5 g per day. The athletes of the control group (n=10) received the main diet without BCAA inclusion. Examination of athletes of both groups was carried out at the beginning of the research and after 4 weeks of the observation period. The actual nutrition of athletes and daily energy consumption have been studied, body composition, the quantitative composition of subpopulations of peripheral blood lymphocytes, cytokine profile and hematological parameters have been determined.

Results and discussion. As a result of a comprehensive survey of athletes, the positive effect of BCAA intake on the phase angle value (7.35±0.28 vs 6.41±0.32 at the beginning of the study, p<0.05) and muscle mass (25.1±0.8 vs 23.4±0.6 kg, p<0.10) has been demonstrated. In the control group these parameters did not change statistically significantly (7.05+0.25 vs 6.78+0.42 and 24.1±1.7 vs 23.8±1.5 kg). The athletes of the main group showed an increase in erythrocyte hemoglobin content (30.0±0.3 vs 29.0±0.2 pg, p<0.05). The relative content of basophilic leukocytes in athletes of the main group decreased by the end of the observation period - from 0.69±0.05 to 0.54±0.05% (p<0.05), that indicated an increase of immune resistance. The biomarker of the immunotropic effect of BCAA was the suppression of IL-4 production (1.6±0.1 to 1.3±0.1 pg/ml, p<0.05) synthesized by Th2 lymphocytes, with switching response to cellular immunity.

Conclusion. The results of this study provide evidence of the effectiveness of BCAA usage in sports’ nutrition for maintaining sport performance, immunity, and the adaptive potential of combat sport athletes.

Estimation of the diet and metabolic status of hokkey players with different body mass

Abstract

Intense physical activity can lead to endogenous intoxication of the organism of athletes. Metabolic stress occurs due to the acceleration of plastic and energy exchanges and the accumulation of products of incomplete metabolism, lipid peroxidation processes are activated, changes occur in the hypothalamic-pituitary-adrenal system of the organism. One of the first and most powerful means of recovery is nutrition.

The aim of the work is to evaluate biochemical blood parameters characterizing the metabolic processes in athletes with different body weight under organized nutrition.

Material and methods. Three groups of hockey players aged 26.4±0.8 years old were examined, playing in the Continental Hockey League, with different body mass (BM): below the 25th quartile - 1st (n=7), above 75th quartile - 3rd (n=9) and in the zone of 2575 quartile - 2nd (n=17). For the assessment of the consumption of nutrients and energy per day, menu layouts have been analyzed. Blood biochemical parameters (total protein, urea, creatinine, glucose, total cholesterol, high and low density lipoprotein cholesterol, triglycerides’, creatine kinase-MB, alanine aminotransferase, aspartate aminotransferase (AST), testosterone and cortisol), characterizing the metabolic status of the organism, have been determined through 2.5 and 4 months of games. The anabolism index, atherogenic index and De Ritis Ratio have been calculated.

Results and discussion. The energy value of the diet (6693.5 kcal/day), in general, corresponded to the daily needs of athletes (from 5953.2 to 6494.4 kcal/day). Daily calorie intake in the individuals of group 1st was higher than recommended by 13.5%, 2nd - by 3.1%, 3rd - corresponded to the need per 1 kg of BM. Protein level exceeded the norm for individuals of groups 1-3 by 51.4-27.0%; fats - by 34.0-12.4%. The amount of carbohydrates complied with the norm only for persons of group 1st. Athletes of groups 2nd and 3rd received less carbohydrates, respectively by 6.7 and 13.8%. Testosterone level was within the normal range, while cortisol level was significantly higher than norm. The anabolism index indicated that individuals from groups 1st and 2nd were overtraining at all stages of observation, and group 3rd - after 4 months of games. Urea level in the re-examination significantly increased and exceeded the norm by 30.4, 27.4 and 25.3%, respectively, creatinine level also elevated. After 2.5 months of games, total cholesterol in individuals of groups 2nd and 3rd was higher than in group 1st, but did not go beyond the reference limit; after 4 months it exceeded the norm. High-density lipoproteins were lower or within low norm limit; low-density lipoproteins in group 1st slightly increased, and in group 2nd and 3rd exceeded the norm. Atherogenic index increased, exceeding the age norm in all groups. Creatine kinase-MB went beyond the normal range in hockey players of all groups. AST increased in groups 2nd and 3rd, exceeding the norm. De Ritis Ratio in athletes of all groups in each study was above the norm.

Conclusion. In hockey players, signs of catabolism were more pronounced in group 1st, less than in 3rd (cortisol level). The systemic metabolic shift towards an increase in protein catabolism in the same sequence was indicated by the level of urea and creatinine and De Ritis Ratio. Lipid metabolism disorders were more pronounced in individuals of groups 2nd and 3rd. Biochemical indicators showed the presence of overtraining, hypoxia in the heart muscle cells and the activation of biochemical processes in the direction of gluconeogenesis, which was confirmed by the data on insufficient consumption of diet carbohydrates.

Micronutrients in nutrition

Biomarkers of vitamin status in obese school children

Abstract

Inadequate intake of vitamins, noted in children with obesity, reduces the immune system activity, contributes to the metabolic disorders aggravation and may result in comorbidity.

The aim of the work was to study sufficiency with vitamins and carotenoids of children with obesity.

Material and methods. Examination of vitamin D, B2, C, A, E and β-carotene status in 50 children (male 36.0%) aged 11-17 years [median (Me) - 14 years] with obesity [Z-score body mass index (BMI) ≥2.0, Ме=2.86] by determining serum biomarkers has been conducted.

Results and discussion. All of the children had an adequate supply with vitamin C (ascorbic acid level >0.4 mg/dL). Low vitamin A status (retinol <30pg/dl) was revealed in 8% children. Deficiency of vitamin D [25(OH)D<20 ng/ml], vitamin B2 (riboflavin <5 ng/ml) and β-carotene (<10 pg/dl) was detected in 62.0, 38.8 and 74.0% of obese children. The percentage of persons with reduced vitamin E serum level (<0.8 mg/dl) was amounted 54.0%. A severe vitamin D deficit (<10 ng/ml) has been detected in 24.0% of children with Z-score BMI ≥2.86 (median value) and has not been observed in children with lower body weight, whose serum β-carotene median was 1.5 fold higher (p<0.05). No one was adequately supplied with all 5 studied vitamins and β-carotene. The combined deficiency of 3 or more vitamins took place in 54.0% of obese children. Synchronously suboptimal serum level of ascorbic acid (<50 pmol/l), β-carotene (<0.4 pmol/l) and α-tocopherol/cholesterol ratio (<5.0 pmol/mmol) which is a cardiovascular disease risk factor, has been found in 28.0% of children. BMI was inversely associated with 25(OH)D serum concentration (ρ =-0.313, р=0.027). There was a pronounced negative correlation between serum level of β-carotene and atherogenic LDL cholesterol (ρ=-0.514, p<0.001).

Conclusion. The prevalence of combined vitamin D, tocopherol and carotenoids’ inadequacy in obese children indicates the importance of vitamin status correction to reduce the risk of metabolic syndrome.

Provision of vitamin D in the adult population of Western Siberia: a population-based study

Abstract

The results of research in recent years indicate a widespread low intake of vitamin D, its deficiency or lack among the population of many countries around the world. It is of interest to study vitamin D status of the population living at different geographic latitudes and depending on socio-demographic characteristics.

The aim of the research is to analyze vitamin D status of the adult population living in the Omsk Region over the age of 18 in different seasons of the year.

Material and methods. Evaluation of vitamin D status has been carried out in 818 adult residents (325 men and 493 women) aged 18 to 92 years, the median of age - 49 (35; 63) years. Vitamin D status was determined by the level of [25 (OH) D] in serum by the method of immuno-chemiluminescent or electrochemiluminescent analysis. Design: cross-section (simultaneous) uncontrolled epidemiological study. Research period: 2017, from January to December.

Results and discussion. 25.8±1.5% showed optimal vitamin D provision, insufficient vitamin content was found in 32.5±1.6% of studied participants, and deficit in 41.4±1.7%. The median level of 25(OH)D for all subjects was in the suboptimal sufficiency range and amounted to 22.17 (16.5; 30.3) ng/ml. The lowest level of the metabolite has been registered in patients over the age of 80 years - 16.5 (13.2-22.6) ng/ml, at the age of 70- 79 years - 19.1 (12.9-26.9) ng/ml. In persons aged 18-60 years, the median concentrations were higher (22.2-24.8 ng/ml) and did not differ in the age groups. Deficiencies of varying degrees were most prevalent in age groups over 80, 70-79, and 50-59 years. Slightly better sufficiency of men compared with women has been revealed (p=0.052). Seasonal differences were found in the nature of vitamin D supply characterized by a deficit state from January to June [median 18.7 (13.9; 23.5) ng/ml] and a state of insufficiency from July to December [median 24.8 (17.8; 32.04) ng/ml]. The dependence of the level of vitamin D status on the number of sunshine days during the periods of 15-90 days preceding blood collection hasn’t been established.

Conclusion. The problem of insufficiency of vitamin D applies to all age groups of the adult population of the region of Western Siberia, especially those over 70 years of age. For the first half of the year, predominantly deficient states are characteristic, and for the period from July to December - the state of vitamin D insufficiency in the residents.

Mineral profile of black currant (Ribes nigrum L.), growing in the Far Northeast of Russia

Abstract

The aim of the study is to evaluate the mineral profile of black currant fruit (Ribes nigrum l.) growing in the North-East of Russia, on the territory of the Magadan region.

Material and methods. Berry samples were collected within the forest zone of Magadan from wild plants. Atomic emission spectrometry and inductively coupled plasma mass spectrometry were used to determine the content of 25 minerals and trace elements in the objects under study.

Results and discussion. The content of minerals - calcium (64.2 mg%), magnesium (21.6 mg%), sodium (0.3 mg%), phosphorus (51.8 mg%) and trace elements - iodine (1.0 pg%), zinc (0.29 mg%) in black currant fruits (Ribes nigrum l.), growing in the forest zone of Magadan, corresponded to the database of chemical composition of Germany, Spain, Norway, Russia, USA, France, Sweden, Estonia. The content of potassium (180.3 mg%), copper (0.05 mg%), iron (0.4 mg%), manganese (0.1 mg%) was below the reference ranges. A portion (100 g) of black currant berries satisfies the daily requirement of an adult for selenium by 11%, potassium by 7%, phosphorus by 6.5%, calcium, magnesium, copper, manganese - by 5%, iron by 3-4%, zinc by 2%.

Conclusion. The obtained data on the content of minerals and trace elements in the berries of wild black currant growing in the North-East of Russia, can be an addition to and clarification of the information available in the literature and database on the chemical composition of foods.

Diet treatment

Effect of specialized product with modified carbohydrate profile on clinical and metabolic parameters in patients with type 2 diabetes

Abstract

Aim. To evaluate the effect of a low-calorie diet with the inclusion of a specialized product (SP) with a modified carbohydrate profile (dry instant mixture) on the glycemic and metabolic control indicators in patients with DM2.

Material and methods. The study included 30 patients with DM2 with concomitant obesity, grade 1-111, who were on oral sugar-lowering therapy. Within 2 weeks, patients of the main group received a low- calorie diet (1550 kcal/day) with the inclusion of SP with a modified carbohydrate profile (based on maltitol and with sweeteners) with strawberry flavor in the form of a drink (30 g dry mix per 150 ml of water) for the second breakfast instead of a carbohydrate-containing dish, which provided the intake of 7.8 g of protein, 6.1 g of fat, 1.8 g of carbohydrates, 5.6 g of maltitol. The comparison group received a low-calorie diet (1550 kcal/day) without the inclusion of SP. 1n all patients, on the background of complex therapy, anthropometric indices, body composition, parameters of carbohydrate, lipid and protein metabolism, liver function, and lipid peroxidation were assessed.

Results and discussion. 1t was shown that SP inclusion into the hypocaloric diet was accompanied by a significant decrease in the level of basal glycemia by an average of 17.4% from the initial level (p<0.05), serum total cholesterol (TC) and low density lipoproteins cholesterol (LDL-C) on average by 26.9 and 36.2% of baseline, respectively, p<0.05, while in patients of the comparison group, the change in fasting blood glucose was not statistically significant (a decrease of 8.1%), and the decrease in TC and LDL-C was on average 22.1 and 21.0%, respectively (p<0.05). At the same time, against the background of complex therapy, positive dynamic in lipid peroxidation in the main group was observed: the level of blood serum malondialdehyde decreased on average by 25.3% from the baseline values (p<0.05).

Conclusion. The inclusion of SP with a modified carbohydrate profile in a low-calorie diet is accompanied by an improvement in glycemic control, lipid metabolism and antioxidant status of patients with DM2, helping to reduce the risk of developing systemic vascular complications in this disease.

Food quality control and safety

Enzymatic activity of recombinant metallopeptidase for further using in meat industry

Abstract

Enzymatic modification of meat with a high content of connective tissue is an effective mean, allowing to improve its properties and expand its use. Microbial enzymes have been extensively investigated as meat tenderizers. Compliance with safety requirements in terms of forecasting the development of various risks is essential for the use of these enzymes in food industry. The method of producing recombinant protease as a potential candidate for applications on meat tenderization was described in the article.

The aim of this study was the production of recombinant Pichia pastoris with M9 peptidase gene from Aeromonas salmonicida.

Material and methods. Objects: peptidase gene M9 (GenBank: CP000644.1 ASA3723) Aeromonas salmonicida (strain of laboratory collection, isolated from the surface of raw meat), the vector plasmid pPic9K, competent E. coli DH5a cells, competent Pichia pasto -ris GS115 cells, culture fluid (QOL) from recombinant Pichia pastoris clones, beef shank samples. To obtain a recombinant strain, genetic engineering methods, the PCR method, and the bacteriological method were used. Polyacrylamide gel electrophoresis was used to separate and analyze the components of the supernatant. Enzyme activity was evaluated by HPLC-MS/MS using synthesized peptides. The impact of the supernatant from recombinant clones on the connective tissue of raw meat was assessed by histological method.

Results and discussion. A metalloprotease M9 gene was cloned from the Aeromonas salmonicida (2748 bp) and expressed in Pichia pastoris. The molecular mass of the recombinant protein was estimated to be 120 kDa by SDS-PAGE. Histological analyses of the control and enzyme treated beef samples showed degradation intramuscular connective tissue, suggesting its effectiveness on meat tenderization.

Conclusion. The recombinant strain Pichia pastoris, which produces the recombinant M9 peptide of Aeromonas salmonicida, has a specific enzymatic activity against collagen, the main component of the connective tissue of meat. The obtained recombinant peptidase M9 can be used as an enzyme softener of raw meat with a high content of connective tissue.

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CHIEF EDITOR
CHIEF EDITOR
Viktor A. Tutelyan
Full Member of the Russian Academy of Sciences, Doctor of Medical Sciences, Professor, Scientific Director of the Federal Research Centre of Nutrition, Biotechnology and Food Safety (Moscow, Russia)

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