A novel milk-clotting enzyme from Aspergillus oryzae and A. luchuensis is an aspartic endopeptidase PepE presumed to be a vacuolar enzyme

Aspergillus oryzae RIB40 has 11 aspartic endopeptidase genes. We searched for milk-clotting enzymes based on the homology of the deduced amino acid sequence with chymosins. As a result, we identified a milk-clotting enzyme in A. oryzae. We expected other Aspergillus species to have a homologous enzyme with milk-clotting activity, and we found the most homologous aspartic endopeptidase from A. luchuensis had milk-clotting activity. Surprisingly, two enzymes were considered as vacuole enzymes according to a study on A. niger proteases. The two enzymes from A. oryzae and A. luchuensis cleaved a peptide between the 105Phe-106Met bond in κ-casein, similar to chymosin. Although both enzymes showed proteolytic activity using casein as a substrate, the optimum pH values for milk-clotting and proteolytic activities were different. Furthermore, the substrate specificities were highly restricted. Therefore, we expected that the Japanese traditional fermentation agent, koji, could be used as an enzyme source for cheese production.

Results of the complex evaluation of bryndza cheese and the byproduct milk whey with the use of enzyme MTG and its activity degree during storage

The paper examines the question of using the enzyme microbial transglutaminase (mTG) for bryndza cheese production. Microbial transglutaminase belongs to the enzyme family that catalyzes formation of bonds between amino groups. One of the problems in production of high-protein products, in particular, cheeses from goat milk is flabbiness of the clot. The use of mTG in the technological process would allow strengthening the product protein matrix, thereby improving its commercial characteristics. When performing the histological investigation of cheeses with this enzyme type to characterize the state of the protein matrix, the authors established that the product protein structure was more condensed compared to the control samples (without mTG), which affected cheese consistency. Consistency became more rubbery negatively influencing the product sensory properties, which are important traits for a consumer when buying a product. Using a Brookfield texture analyzer, it was shown that structural-mechanical characteristics were improved by 1.5 times for cheese samples produced from cow milk and by 2 times for goat cheese when mTG was used. Analysis of the enzyme catalytic activity showed that this enzyme retained its activity throughout the whole storage period, which is a potential hazard for human health. After shelf-life expiration, a change in the mTG activity was not more than 5% relative to the initial levels. The enzyme activity retained not only in cheese but also in the by-product — cheese whey, which made its processing more difficult.

Formulation of New Media from Dairy and Brewery Wastes for a Sustainable Production of DHA-Rich Oil by Aurantiochytrium mangrovei

Mozzarella stretching water (MSW) is a dairy effluent generated from mozzarella cheese production that does not have a real use and is destined to disposal, causing environmental problems and representing a high disposal cost for dairy producers. Spent brewery yeast (SBY) is another promising food waste produced after brewery manufacturing that could be recycled in new biotechnological processes. Aurantiochytrium mangrovei is an aquatic protist known as producer of bioactive lipids such as omega 3 long chain polyunsaturated fatty acids (ω3 LC-PUFA), in particular docosahexaenoic acid (DHA). In this work MSW and SBY have been used to formulate new sustainable growth media for A. mangrovei cultivation and production of DHA in an attempt to valorize these effluents. MSW required an enzymatic hydrolysis to enhance the biomass production. The new media obtained from hydrolysed MSW was also optimized using response surface methodologies, obtaining 10.14 g L−1 of biomass in optimized medium, with a DHA content of 1.21 g L−1.

Productive and technological characteristics of goat farmers in Comondú, Baja California Sur

To identify productive characteristics through the technological indicators adopted by goats farmers at theComondú municipality, state of Baja California Sur, Mexico. A survey consisting of semi-structured questionswas designed to obtain multi-criteria information on the variables of technological, economic, social, andmultilevel indicators. The production units (PUs) were classified by the cluster analysis of means statisticalmethod in the SAS software, allowing to identify four groups of producers of 10.33, 69, 10.33, and 10.33 % ofthem. The social indicator demonstrated differences between UPs regard their education level, non-inclusionof women in the activity, total annual income, and whether or not they are members of an association. Thetechnological indicator revealed differences in their distance from the UPs to the community, road conditions,area of the UP, available area for planting, water sources, herd size, availability to facilities, machinery, andequipment. The economic indicator showed differences between UPs in their agricultural complementaryactivities, economic dependence, milk production, cheese production, animal wastes, goat production, andtheir respective sales values. The conclusion is that this information is useful for particularly attending to theneeds and will allow defining the precise kind of intervention in the management practices or the requiredmanagement.

Optimization of Parameters Using Response Surface Methodology to Develop a Novel Kefir-Like Functional Beverage from Cheese Whey Enriched with Myrtle Juice

Whey, liquid wastewater from cheese production, is one of the sources of dietary protein and lactose that are still largely unused for human consumption. It is only in recent years that it has aroused the interest of industries and sought as a valuable raw material and thus represents an opportunity for the manufacture of new products. The manufacture of fermented whey drink requires the mixing of whey with fruit juice or an aromatic plant to improve its organoleptic properties and acceptability. Myrtle, an aromatic medicinal plant, known for its health benefits is not well exploited for making dairy products. This is the first report on the development of kefir-myrtle beverage. Three factors were optimized (whey permeates (%), myrtle’s juice (%), and kefir grains as inoculum (%)) using a central composite design with response surface methodology. The analyses showed that the number of lactic acid bacteria (LAB) and yeast cells varied from 5.4 to 9.2 log10 CFU/mL and from 4.3 to 6.2 log10 CFU/mL, respectively. A decrease in pH and an increase in the total polyphenol content and antioxidant activity were observed. The analysis of variance indicated the goodness of fit of the model with R2 from 0.827 to 0.966. The absolute average deviation values of each model were low and ranged from 1.61% to 4.23%. The optimized fermented kefir whey beverage accomplished an overall acceptability of 5.41 (1 to 9 preference scale) and a high number of LAB cells (8.53 log10 CFU/mL). The viability of LAB and yeast cell was maintained at 7.61 and 6.19 log10 CFU/mL, respectively, after 14 days of storage.

Organoleptic and Chemical Analysis Characteristics of Sulguni Stored in Beeswax

In the paper showed organoleptic and chemical analysis of sulguni that is made of traditional technology and sulguni in beeswax has been carried out to study the effects of bee wax layer on the organoleptic and chemical parameters of sulguni. Some main factors are obstacle those make influence on sulguni, such as: cheese weight loss, fat oxidation and enzymatic breakdown. On the base of analysis the use of beeswax layer improves the physical stability of sulguni, at the same time the visual and tactile characteristics of the surface are improved as well. Moreover, it prevents the existence of mucus and mold on the surface, as well as protects the cheese from moisture loss and sulguni also retains its taste properties. Vacuum packaging cheese production in beeswax layer can be considered as the new, ecologically clean and safe alternative.