11 research outputs found
Study of transhydrogenase systems features in the mutants of the yeast pachysolen tannophilus for the production of ethanol and xylitol from agricultural wastes
The key catabolic enzymes of D-xylose, an important structural component of different
agricultural wastes, were studied in cells of mutant strains of the xylose-assimilating yeast
Pachysolen tannophilus. The evaluation of catalytic activity and cofactor specificity of xylose
reductase (ЕС 1.1.1.307) and xylitol dehydrogenase (ЕС 1.1.1.9) confirmed the dependence of
intracellular catabolic pathway for D-xy lose on the NAD×H/NADP×H ratio, formed under
microaerobic conditions. The study of total activity of some NAD+
/NAP×H-dependent
dehydrogenases revealed the metabolic characteristics of the yeast cells, which could ensure
selective ethanol or xylitol production. Thus, the efficient involvement of D-xylose into the
Embden–Meyerhof–Parnas pathway provided not only the high activities of xylose reductase and
xylitol dehydrogenase, but also of 1-glycerophosphate dehydrogenase (EC 1.1.1.8) and lactate
dehydrogenase (ЕС 1.1.1.27), respectively. The inhibition of activity of these enzymes led to
selective production of xylitol from D-xylose. On the base of the experimental results, the
principles of metabolic engineering of xylose-assimilating yeasts were formulated. The
possibility of bioethanol and xylitol production from different agricultural wastes using xyloseassimilating yeasts are discussed
Biochemical composition and quality of herring preserves with addition of bio-protective cultures
Herrings rich in vitamins B12, A, D, minerals, including calcium, potassium,
magnesium, iodine, possess high levels of lysine, tyrosine, phenylalanine and tryptophan, as well
as omega-3 unsaturated fatty acids, namely eicosapentanoic, docosahexoenoic and
docosapentoenoic. To suppress the microbiological spoilage of fish preserves, it is promising to
use bio-protective cultures that have minimal impact on the production process and product
properties. Bacterial strains are able to exert a static effect on the microflora, which causes
biodeterioration of food products. Microorganisms as part of bio-protective cultures are included
in the fermentation process, so they can be attributed to ordinary food ingredients, so there is no
need to put separate information on the packaging. The chemical composition of the frozen
Atlantic and Pacific herring fillet, the amino acid composition of proteins, and the fatty acid
composition of lipids were studied. The difference between Atlantic and Pacific herrings was
detected, which consists in a significantly higher content of docosahexaenoic acid. The difference
in the fractional composition of triacylglycerols for the Atlantic and Pacific herring was
established. The microflora of SafePro B-2 biological product (Chr. Hansen GmbH), containing
multiple strains of Lactobacillus sakei, and the viability of the culture in preserves fillings were
studied. The experimental development of canned food with SafePro B-2 additives was carried
out. Microbiological, organoleptic and biochemical indicators of the preserves quality during cold
storage were studied. The influence of introduced culture on the dynamics of preserves curing
period and their shelf life was established
Shelf life extension of minimally processed vegetables using combinations of bacterial bioprotection and modified atmosphere packaging
The objective of the work: to study the effect of combination of bacterial bioprotective
cultures and modified atmosphere packaging for prolonging the refrigerated storage period of
minimally processed vegetables. Sweet pepper, zucchini, eggplant, celery stalks were used for
preparation of minimally processed vegetables. SafePro® bio-products from Chr. Hansen
(Denmark) containing strains of Lactobacillus sakei, Pediococcus acidilactici, Lactobacillus
сurvatus, Leuconostoc carnosum were used as bioconservatives. For packaging minimally
processed vegetables, the bags made of flat multilayer PA/adhesive/PE films and composite
PET/A1/PE film material were used. The bags were filled with gas mixtures including nitrogen
and carbon dioxide. Storage of packaged minimally processed vegetables was carried out in a
refrigerator at a temperature of (4 ± 2) °C for 16 days. The viability of cultures Lactobacillus
sakei, Pediococcus acidilactici, Lactobacillus curvatus, Leuconostoc carnosum in modified
atmosphere packaging was studied. It was revealed that the gas mixture of 60% nitrogen and 40%
carbon dioxide and the culture of Lactobacillus sakei contribute to the preservation of the quality
of fresh-cutsweet pepper, eggplant and zucchini, and Leuconostoc carnosum is the more effective
for celery storing. In the process of refrigerated storage for 14 days, the solids content in the
experimental samples increased 1.3–2.1 times, the loss of organic substances was 26–50%,
depending on the type of vegetables. The developed technology for the refrigeration preservation
of minimally processed vegetables using bio-products treatment and in modified atmosphere
packaging made it possible to increase the shelf life of fresh-cut vegetables by 2 times
Use of lipids of Chlorella microalgae in poultry meat marinades and sauces recipes
ArticleThe aim of this study is to develop formulations and technologies for fermented poultry
meat products with the addition of whey and lipid extracts obtained from Chlorella microalgae.
Lyophilized microalgal biomass was obtained from cell suspensions of Chlorella sorokiniana
(strain 211-8k) cultivated in a closed photobioreactor under laboratory conditions. For the cell
wall disintegration, the biomass samples were homogenized using a high-speed homogenizer at
10,000 vol min-1
for 5 minutes. The lipid extraction was performed on a Sohxlet apparatus Buchi
E-812 SOX with the solvent extraction system ethanol: n-hexane (1: 9). The higher fatty acids
composition of the obtained microalgal lipid extracts was determined by gas chromatography
with flame-ionization detection using nitrogen as a carrier gas. The ω-3 and ω-6 content
represented 26.59% and 19.05% respectively, which indicates that these lipid extracts have high
nutritional values. The curd whey was obtained from cow's milk of summer and winter production
from 2017 to 2018 (Lomonosov district auxiliary farm, Leningrad region); and lyophilized Direct
Vat Set (DVS) cultures (Ch. Hansen, Denmark). The organic acids and carbohydrate content in
the serum was determined by ion-exclusion HPLC. The FD-DVS CHN-19 culture was selected
to produce a serum with improved organoleptic characteristics and a lower propionic acid content
(0.01 g L
-1
). To obtain an optimal ω-3 / ω-6 ratio, a phyto-additive mixture based on sunflower
oil and lipid extracts from C. sorokiniana microalgae at a ratio of 5–10: 1 is proposed to be used
in recipes and technologies of sauces and marinades. It is established that the use of curd whey
marinades allow to increase the water-holding capacity (WHC) by 6−8% and to reduce losses
during heat treatment of poultry meat from 2 to 11%
A method for obtaining plastid pigments from the biomass of Chlorella microalgae
Microalgae are distinguished from land plants by the high content of plastid pigments
and the biodiversity of carotenoids. The aim of this study is to develop a technology for extracting
a pigment complex from the biomass of the microalgae of the genus Chlorella and to determine
the extracted pigments’ composition. To obtain biomass, a crude cell suspension of microalgae
was used, which was obtained under laboratory conditions for pre-culture cultivation of
C. sorokiniana (strain 211-8k). The extraction of plastid pigments from air-dry biomass after
disintegration of cell membrane was performed in the 40 kHz mode. It was found that the highest
pigment content in ethanol extracts was observed after 30 min (870.0 ± 27.1 mg L
-1
) at 45−50 °C.
The pigments’ composition in the resulting total extracts was determined by spectrophotometry
and the Reverse Phase HPLC method. The established content of chlorophyll a in the obtained
extracts was 537.5 ± 10.0 mg L
-1
, the content of chlorophyll b was 182.5 ± 27.5 mg L
-1
; the
maximum output of the amount of carotenoids in extracts was 150.0 ± 10.0 mg L
-1
. Thus, the
main identified forms of carotenoids in extracts from the biomass of microalgae C. sorokiniana
were xanthophylls: lutein and fucoxanthin (18.6 and 4.7% of the amount of pigment in extract,
respectively) and β-carotene (1.8% of the amount of pigment). It is planned to further fractionate
the obtained total extracts of the pigment complex to obtain various forms of chlorophylls and
carotenoids to study the spectrum of physiological activity of plastid pigments
New educational technologies as a means of cross - regional cooperation in the field of food raw material and product safety control
International e-learning resource in the field of food product quality and veterinary disease control based on Government requirements of the European Union and Eurasian Economic Union has been created and tested. This resource consists of the one general professional cycle and five professional modules, about 60% of them are in distance e-learning format. The modularity of the educational resource allows the employer or students to choose a training program format, as well as the amount of distance learning or classroom training hours for different groups of specialists in the field of food quality and veterinary control: chiefs of quality control center or laboratories, veterinarians, microbiologists, specialists of veterinary diagnostics laboratories, chemical engineers. The involvement of participants from EU and EEU-countries in the educational process is important for the development of interregional and international activities, the creation of the unified legal framework in the field of food security in many countries