Natural biopolymers are an interesting resource for edible films production, as they are environmentally friendly packaging materials. The possibilities of the application of main animal proteins and natural polysaccharides are considered in the review, including the sources, structure, and limitations of usage. The main ways for overcoming the limitations caused by the physico-chemical properties of biopolymers are also discussed, including composites approaches, plasticizers, and the addition of crosslinking agents. Approaches for the production of biopolymer-based films and coatings are classified according to wet and dried processes and considered depending on biopolymer types. The methods for mechanical, physico-chemical, hydration, and uniformity estimation of edible films are reviewed.

The global trend towards conscious consumption plays an important role in consumer preferences regarding both the composition and quality of food and packaging materials, including sustainable ones. The development of biodegradable active packaging materials could reduce both the negative impact on the environment due to a decrease in the use of oil-based plastics and the amount of synthetic preservatives. This review discusses relevant functional additives for improving the bioactivity of biopolymer-based films. Addition of plant, microbial, animal and organic nanoparticles into bio-based films is discussed. Changes in mechanical, transparency, water and oxygen barrier properties are reviewed. Since microbial and oxidative deterioration are the main causes of food spoilage, antimicrobial and antioxidant properties of natural additives are discussed, including perspective ones for the development of biodegradable active packaging.

Biofilm contamination in food production threatens food quality and safety, and causes bacterial infections. Study of food biofilms (BF) is of great importance. The taxonomic composition and structural organization of five foods BF taken in different workshops of a meat-processing plant (Moscow, RF) were studied. Samples were taken from the surface of technological equipment and premises. Metagenomic analysis showed both similarities in the presented microorganisms dominating in different samples, and unique families prevailing on certain objects were noted. The bacteria found belonged to 11 phyla (no archaea). The dominant ones were Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. The greatest diversity was in BFs taken from the cutting table of raw material. Biofilms’ bacteria may be the cause of meat, fish and dairy products spoilage possible representatives include Pseudomonas, Flavobacterium, Arcobacter, Vagococcus, Chryseobacterium, Carnobacterium, etc.). Opportunistic human and animal pathogens (possible representatives include Arcobacter, Corynebacterium, Kocuria, etc.) were also found. Electron-microscopic studies of BF thin sections revealed the following: (1) the diversity of cell morphotypes specific to multispecies BFs; (2) morphological similarity of cells in BFs from different samples, micro-colonial growth; (3) age heterogeneity of cells within the same microcolony (vegetative and autolyzed cells, resting forms); (4) heterogeneity of the polymer matrix chemical nature according to ruthenium red staining.

Влияние дигидрокверцетина на клинические и биохимические показатели крови у свиней в условиях стрессовых нагрузок

The slaughter of farm animals generates a large number of by-products. Meat waste management includes various methods, but cost-effective technologies are still in priority. This manuscript reports the results of the study of antimicrobial activity of substances isolated from such wastes of meat processing industry as bovine and pork mucous membranes and epithelial tissues. Proteomic study included two-dimensional electrophoresis with following mass spectrometric identification. Antimicrobial activity against L. monocytogenes, P. aeruginosa and S. aureus of neutralized native extracts and after enzymatic treatment as well as its ultrafiltrates was determined by flow cytometry with EvaGreen and PI dyes. It was shown that a large number of histones were found in bovine mucous membranes as well as several tissue-specific proteins, which would be a precursor of bioactive peptides. Bovine mucous membranes of the tongue and nasal cavity possessed the greatest activity in relation to P. aeruginosa, the rate of surviving cells decreased to 22.0%. Bovine mucous membranes of the rectum and the oral cavity, submandibular lymph nodes, pig mucous membranes of the larynx, tongue, lips, and rectum increased dead cells count up to 40% of all cells. Bovine nasal mucosa and pork mucous of labial cavity possessed the greatest activity against S. aureus, the rate of surviving cells did not exceed 10.0%. Determination of antimicrobial action against L. monocytogenes of native samples and treated with trypsin showed that bovine mucous membranes of the rectum and oral cavity, pork mucosa of the lips and submandibular glands were the most active. Treatment with trypsin or ultrafiltration demonstrated different effects on activity of samples. It was shown the perspectivity of recycling of such type of by-products into effective and demanded substances which can be used, for example, in the food industry as an alternative to chemical preservatives.

The porcine pancreas contains various enzymes, structural, regulatory, secretory, receptor and other biologically active substances that ensure both the functioning of the organ and its biological role in the organism. The aim of this work was to study the influence of pH changes in 0.9% sodium chloride solution used as an extractant on the efficiency of bioactive protein isolation from the porcine pancreas. The extraction was carried out with the 0.9% NaCl, 0.9% NaCl pH=4 and 0.9% NaCl pH= 8.5 with a stirring speed of 400 rpm for 150 min at 4 ºC; the ratio of pancreas: extractant was 1:5, the supernatant was separated by centrifugation. The protein concentration was measured by a biuret reaction on a semi-automatic biochemical analyzer Biochem SA. The proteomic composition of extracts and native pancreas was evaluated by 10% SDS-PAGE according to Laemmli method in the “VE10” chamber. Digital images of electrophoregrams were obtained using a Bio-5000 Plus scanner, edited in a graphic editor and analyzed using ImageJ software. When determining the intensity of protein fractions, it was noted that the use of 0.9% NaCl contributed to a greater yield of proteins with molecular weights of 200 kDa, 150 kDa, 69 kDa, 52 kDa and 33 kDa into the extractant; a pH shift to the acidic area stimulated the yield of fractions with molecular weights of 130 kDa, 50 kDa, 49 kDa, 45 kDa, 40 kDa, 30 kDa and 27kDa, and a pH shift to the alkaline area — only 47 kDa and 42 kDa. Most pancreas proteolytic enzymes have a molecular weight in a range of 34–23kDa, excepting the immature form of carboxypeptidases with MW 45–47kDa. The greatest intensity of protein bands was observed in the region with MW less than 33kDa on the obtained electrophoregrams. The presence of intense protein fractions in the region of molecular weights of less than 50–52kDa and 40kDa was also noted, which may correspond to enzymes such as pancreatic lipase and phospholipase A2, and the presence of protein fractions with MW above 130 kDa corresponding to various types and isoforms of collagen and laminin. In addition, such processes as protein aggregation and proteolysis can also influence the molecular weight distribution of protein fractions.