2021, Vol. 19, Special Issue 3

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/6919

Sirvi

Nüüd näidatakse 1 - 8 8

Obtention of omega-3-fatty acids cryoconcentrated fish oil from by-products of preserves industry
(2021) Kuprina, E.; Filipov, V.; Yakkola, A.; Manuilov, A.; Abramzon, V.; Kremenevskaya, M.; Zashikhin, M.; Kuznetsova, A.; Kopylov, A.; Maksimenkov, A.
The technology for obtaining and cryoconcentration of high-quality fish oil from collagen-containing wastes of slightly salted herring under gentle conditions using electrochemically obtained catholytes has been developed. Physicochemical analysis of raw materials was carried out and the yields of products from raw materials at all stages of processing were determined. Concentration of omega-3 fatty acids in oil was carried out using the cryo method. The main phase transitions in oil with decreasing temperature have been determined. The mass yields were determined and the biochemical composition of the cryoconcentrated fish oil fractions was investigated. It was defined the temperature of -14° С at which a phase transition is observed, providing an increase in the concentration of omega-3 fatty acids in oil by 3 times. The usage of cryoconcentrated fish oil allows to produce biologically active food supplement or raw materials for a functional food.
Evaluation of selected lactic acid bacteria as starter cultures for gluten-free sourdough bread production
(2021) Parakhina, O.; Lokachuk, M.; Kuznetsova, L.; Savkina, O.; Pavlovskaya, E.; Gavrilova, T.
Sourdough is one of the most promising technologies for gluten-free bread. The selection of appropriate starter cultures for the production of gluten-free sourdoughs is of a great importance, since not all microorganisms can adapt equally to the same raw material. The aim was to create a new starter microbial composition for gluten-free sourdough preparation, allowing improving the quality and the microbiological safety of gluten-free bread. Screening was conducted on 8 strains of lactic acid bacteria (LAB) and 5 strains of yeast previously isolated from spontaneously fermenting rice and buckwheat sourdoughs. The strain S. cerevisiae Y205 had the highest fermentative activity and alcohols content. The lactic acid bacteria L. brevis E139 and L. plantarum Е138 were also experimentally selected for new gluten-free sourdoughs on the basis of acidity and volatile acids production and antagonistic activity. Two types of microbial composition were created and its influence on sourdough biotechnological indicators was studied. Sourdough with L. plantarum Е138 had in 1.2 times lower titratable acidity, in 3.4 times lower volatile acids content compared to sourdough with L. brevis E139. Alcohol content was the same in both sourdoughs similarly to yeast cells amount. Sourdough dough proofing time increased in 1.2–1.3 times compared to the control. Sourdough did not affect the specific volume, porosity and compressibility of gluten-free bread, but its sensory characteristics were improved. Bread made with sourdoughs had more pronounced taste and flavor, brighter crust color and better texture compared bread without sourdough. The microbiological safety of sourdough gluten-free bread was also increased, especially when L. brevis E139 was used.
Improving single cell protein yields and amino acid profile via mutagenesis: review of applicable amino acid inhibitors for mutant selection
(2021) Spalvins, K.; Raita, S.; Valters, K.; Blumberga, D.
Single cell protein (SCP) is a good alternative for substituting plant and animal derived dietary proteins, since SCP production is more environmentally friendly, consumes less water, requires smaller land areas and its effect on climate change is much less pronounced than it is in the case of agriculturally derived proteins. Another advantage of SCP is that it is possible to use a wide variety of biodegradable agro-industrial by-products for the cultivation of SCP producing microorganisms. However, to make single cell protein technology more widely available and improve its economic viability in such markets as animal and fish feed industries, it is necessary to improve the protein yields and amino acid profiles in microorganism strains capable of using agro-industrial by-products. One way to improve the strains used in the process is to create and select SCP-rich mutants. In this review authors propose a novel approach to create SCP-rich mutants with improved total protein content and essential amino acid profiles. In this approach amino acid inhibitors are used to create selective pressure on created mutants. It is expected that mutants with the most pronounced growth would either have higher total protein content, increased essential amino acid concentrations or both, when cultivated on selective plates containing one or multiple amino acid inhibitors. This paper reviews the most suitable groups of amino acid inhibitors that could be used for selection of new strains of SCP-producing microorganisms.
A perspective of the Portuguese consumer awareness, beliefs and preferences towards piglet castration methods and its implications on the meat quality
(2021) Pereira Pinto, R.; Vaz-Velho, M.
Neutering male piglets by surgical procedures without anaesthesia, with analgesia and/or anaesthesia and, recently, immunological-chemical castration are practices to avoid unwanted or aggressive sexual behaviour, and to prevent the development of meat boar taint. This exploratory study aims to investigate Portuguese consumer’s awareness, beliefs and attitudes in issues like boar taint, piglet’s castration and pork meat quality, observing possible demographic trends. It is also intended to identify clusters of consumers with similar attitudes, crossing them with demographic data to verify the existence of patterns in Portugal related to these issues. To attain this objective, a consumer’s survey was performed through an online questionnaire open for 30 days. A total of 158 respondents completed the survey. Almost a half (46%) of respondents stated their unknowledge about boar taint. Surgical castration and its effects are topics with which older consumers with a rural background are more familiar with, while immunological-chemical castration is still unknown to most consumers: 65% of consumers said they were not aware of this method, and 75% did not know whether it is an effective method for eliminating boar taint. Hierarchical clustering followed by K-means analysis segmented consumers into three clusters characterized according to their opinions, mainly divided by ethical and chemical-free orientations and by a more conservative meat quality and flavour-oriented attitudes, generally independent of prevailing demographics. In general, there were no defined opinions about the subjects under study, due mainly to the lack of information or knowledge. Nevertheless, cluster classification revealed differences in consumer’s opinions, especially regarding the reasons for castration and the pain inflicted, about meat quality and the willingness to buy pork from entire males or to pay more for this type of product.
Characterization of red raspberry (Rubus idaeus L.) for their physicochemical and morphological properties
(2021) Augšpole, I.; Romanova, I.; Liniņa, A.; Dimiņš, F.
Different raspberry cultivars are grown in Latvia suitable both for fresh market and for processing. Fresh local red raspberry is available for consumers from July to October. Information about the physical, chemical, and morphology properties of raspberry fruit is essential for understanding the behavior of the product during the postharvest operations such as harvesting, transporting, sorting, grading, packaging and storage. Knowledge of the physicochemical properties of red raspberries is essential because variations in the levels of these properties may exist between cultivars. New varieties of plants were used to describe and compare the fruit quality of red raspberry cultivars: ‘Daiga’, ‘Shahrazada’, ‘Norna’ and ‘Polana’ grown in Zemgales region of Latvia. The samples were collected from farm ‘Pluģi’ the full stage of ripening. The current research aimed to investigate and determine the chemical composition (total phenolic content (TPC), total flavonoid content (TFC), titratable acidity (TAc), total soluble solids content of raspberry fruits, the physical parameter pH, and color. Presented morphological parameters of fruit included their weight, receptacle length (Rl), receptacle width (Rw), fruit length (Fl), fruit width (Fw), weight of fruit (M), number of seeds. Research results showed significant differences in all chemical and physical characteristics as well as in morphology properties (P < 0.05) between cultivars.
Effects of α-amylase, endo-xylanase and exoprotease combination on dough properties and bread quality
(2021) Kostyuchenko, M.; Martirosyan, V.; Nosova, M.; Dremucheva, G.; Nevskaya, E.; Savkina, O.
The enzymes composition is an actual alternative to chemicals to improve functional properties of flours and to generate changes in the structure of the dough and bread quality. The objective of this study was to analyze the individual and synergistic effects of enzymes preparation (α-amylase, endo-xylanase and exoprotease), newly produced in Russia, on dough properties and bread quality made from wheat flour with different amylolytic activity. Reofermentometric results revealed decreases in gas-forming capacity of dough by 10.0–13.9% when single α-amylase preparates were used. The α-amylase addition had significant effect on gas retention coefficient in flour possessed low amylolytic activity. The effect of endo-xylanase and exoprotease on hydration and amount of wheat gluten was established. The fractional composition of gluten proteins in the dough made with combination of endo-xylanase and exoprotease was established using Lowry method immediately after kneading and after fermentation. It was found that mainly water-soluble, alcohol-soluble and alkaline-soluble proteins were undergone by transformation. The bread with enzymes had a higher specific volume, porosity and aldehyde content and lower shape stability indicator than the control bread made without enzymes. Bread with enzymes was characterized by tenderer and not crumbly crumb with developed thin-walled uniform porosity compared to the control. The crusts were more brightly colored. The combined usage of α-amylase and endo-xylanase and exoprotease retarded bread staling during 5-day storage period. New enzyme composition may be a potentially strong candidate for future applications in the bread-making industry.
Measurability of quality in fermentation process of rice wine by IoT in the field of industry 4.0
(2021) Vošahlík, J.; Hart, J.
The article inquiries into the issue of automation of the rice wine fermentation process in the field of industry 4.0. Fermentation is the process of converting D-glucose into ethanol along with oxidation of reduced coenzymes (fermentation). This is known as ethanol fermentation, which takes place anaerobically in the presence of yeast. The fermentation is being improved by automation (sensors, etc.). The main aim is to develop an experimental automation environment in industry 4.0 for the process of rice wine fermentation. During the rice wine fermentation process, variety of measurable attributes are created which affect the quality of the resulting product. They can be monitored with the help of automation elements (pH, temperature, humidity etc.). In case of an experimental environment development, it is therefore important to select appropriately the sensory that can record the measurable attributes. At the same time, the sensory must be at a level of reliability that guarantee their sufficient use in the mentioned experimental environment for the rice wine fermentation. The result is that, if the right environment is chosen, the quality of the fermented wine will improve.
Evaluation of ozone influence on wheat grain quality during active drying
(2021) Straumite, E.; Rucins, A.; Viesturs, D.; Kleperis, J.; Kristins, A.
The aim of this study was to evaluate the effect of ozone on the quality of wheat grain during air ventilation drying process. After harvesting, the wheat grain was placed in two storage tanks. In one storage tank for grain drying was used air but in the other - ozone as the drying agent. The following quality parameters - moisture, water activity, gluten, starch and protein content, as well as the total plate count of microorganisms were determined during storage. Wheat grain quality parameters were analysed by taking samples from the top and bottom of the storage tanks. Two-year experiments showed that ozone treatment did not significantly affect (P > 0.05) the moisture content, water activity, gluten, starch and protein content of the analysed wheat grain, but all parameters were significantly affected (P < 0.05) by the sampling location - top or bottom of the storage tank. All samples taken from the top of the tanks throughout the drying process had higher water activity (aw < 0.800). It should be noted that in both series of experiments it was found that there is a very large difference (up to 10%) in grain moisture between grain sampled at the top and bottom of the tanks. Favourable conditions for the development of microorganisms are increased moisture and free water available in the products and raw materials. According to the results obtained in the experiments, it can be concluded that the total plate count in the analysed wheat grain did not exceed the permissible norms (105 CFU g -1 ).

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