Probiotic Potential and Functional Properties of Lactobacillus Reuteri, Lactobacillus Rhamnosus and Lactobacillus Helveticus: A Comparative Study

This study was conducted to evaluate and comparethe probiotic propertiesofLactobacillus helveticusNK1, Lactobacillus rhamnosusF and Lactobacillus reuteriLR1lactobacilli strains.Changes in pH, cell growth, proteolytic activity, antioxidantactivity, and angiotensin-converting enzyme(ACE)inhibitoryactivity were monitored during fermentation ofreconstituted skim milk (RSM) by pure cultures of lactobacilli.Among the tested strains, L. helveticusNK1 showed the highest proteolytic, ACE inhibitoryand antioxidantactivitiesduring milk fermentation,followed by L. rhamnosus F and L. reuteriLR1.The promising capability of all of the lactobacilli strains to release bioactivepeptides from the milk proteins was demonstrated. Keywords: Lactobacillus, probiotic, milk fermentation, bioactive peptides

PRODUCTION TECHNOLOGY OF FRUIT-FILLED COTTAGE CHEESE FOR BABY FOOD OVER 6 MONTHS OF AGE

Currently, cottage cheese is one of the leading dairy products for infants’ nutrition. Today, the urgent task is to expand the range of sour-milk products by developing a technology for cottage cheese production with the addition of a fruit filler. The object of research is cottage cheese for the diet of children over six months. The cottage cheese is produced from whole milk subjected to high-temperature treatment with the use of starter microorganisms and with the addition of fruit filler “Banana”. The children’s curd recipe developed by the authors included the following raw materials and components: milk with the mass fraction of fat 3.4 %, skim milk with the mass fraction of fat 0.05 %, direct injection starter Flora C-170, fruit filler “Banana”. Production technology included the following stages: receiving and preparing raw materials, normalization of milk, homogenization, pasteurization and cooling of the normalized mixture, fermentation, ultrafiltration of curd clot, cooling and ripening of the product. The authors conducted laboratory studies of cottage cheese to assess the quality and safety of the resulting product. The products meet the requirements of GOST 32927-2014 for organoleptic indicators: taste and smell, appearance and consistency, colour. The products also meet the needs of the Technical Regulations of the Customs Union (TR CU) 033/2013 “On safety of milk and dairy products” in terms of microbiological and antibiotic content.

Isolation of a Leuconostoc mesenteroides ssp. jonggajibkimchii strain from Parona leatherjacket (Parona signata): behavior in vegetal matrices fermentation

A Gram-positive, facultatively anaerobic, gas-forming, catalase-negative, nonmotile, non-sporeforming, vancomycin-resistant, and ovoid-shaped bacterium, designated strain Tw234, was isolated from the intestinal tract of Parona leatherjacket (Parona signata). The strain grew in the presence of 0–6% (w/v) NaCl, at pH 3.5–8.5 and 8–40 °C; optimum growth was achieved at 1% (w/v) NaCl, at pH 6.0 and 30–32 °C. Exopolysacharides production was detected by the solidification test of skim milk supplemented with sucrose in the temperature range of 8 to 30 °C. Results of phylogenetic analysis based on the 16S rRNA gene sequence similarity indicated that strain Tw234 was closed related to the genus Leuconostoc and 100% homology with the type strain Ln. mesenteroides ssp. jonggajibkimchii DRC1506 (KCCM 43249, JCM 31787). The evaluation of growth and acidification rates were carried out in white cabbage and Chinese cabbage and compared with the strain Ln. mesenteroides ssp. jonggajibkimchii RCTw1.1, isolated from the spontaneous fermentation of red cabbage. No significant differences were observed between the behaviors of the two strains. The strain Tw234 displayed higher growth and acidification rates in controlled fermentation of white cabbage compared with those obtained in Chinese cabbage. New trends are targeted on the isolation and selection of strains to achieve controlled fermentation of vegetables that may ensure uniform quality. The results obtained in this work suggest that strain Tw234 harbored technological useful properties for its potential use as a starter in controlled vegetable fermentations.

Isolation and identification of protease‐producing bacteria from sludge and sediment soil around Adama, Ethiopia

Proteases are enzymes used in industries such the production and processing of detergents, food, leather, and silk. The aim of this study was to isolate and identify protease‐producing bacteria from a sludge disposal site and from sediments. Soil samples were collected separately from the selected area. Samples weighing 1 g were serially diluted and spread onto skim milk agar. A total of 16 bacteria species were isolated from the study samples. Four bacterial isolates showed high proteolytic activity and were selected for enzymatic study based on their zone of proteolysis. The isolates were identified based on biochemical tests. The results indicated that the isolated bacteria were E. coli (99.69%), Pseudomonas putrefaciens (Shewanella putrefaciens) (91.61%), Bacillus carboniphilus (92.78%), and Lysinibacillus sphaericus (98.4%). The crude protease enzymes produced by these bacterial isolates showed promising results for application in dehairing and destaining as detergent additives. Bacillus carboniphilus showed the best level of activity and was selected as the most potent protease‐producing bacteria for both dehairing and destaining ability. Soils from sludge disposal sites and sediments from around tannery wastes could be good sources from which to isolate alkaline protease‐producing bacteria.

Production technology and quality assessment of milk shakes for baby food with vitamin complex enrichment

Diversification of dairy products for baby food is a topical trend in the development of the dairy industry. In the process of producing an ultra-heat-treated (UHT) milkshake, milk with a mass fraction of fat 3.5 %, skim milk with a mass fraction of fat 0.5 %, fruit filling "Cherry" and a vitamin premix are used. The technological process of production includes the acceptance of raw materials, assessment of their quality in accordance with regulatory documents; heat treatment of raw milk; preparation of a normalized mixture; adding ingredients. The prepared mixture is sent for deaeration to a flow-through apparatus, then to a homogenizer, where it is subjected to ultra-pasteurization at a temperature of 136 ± 2 °C with a holding time of 4 ± 1 s. The final stage of cocktail production is packaging and intermediate storage. The resulting product was tested in the laboratory for organoleptic and physicochemical indicators. During the experiments, it has been found that the taste, smell, colour, appearance and consistency meet the requirements of state standards. The content of protein, fat, carbohydrates, calcium and titratable acidity are within acceptable values; the content of vitamins A, D, E, B is higher than the minimum values. The research results on safety indicators meet the requirements of technical regulations. Antibiotics, GMO-derived materials and preservatives are not found in the product. The energy value of the baby milk shake is 63.7 kcal (266.6 kJ/100 g of product).