31 research outputs found

    ВЛИЯНИЕ ТРАДИЦИОННОГО ИЛИ ШОКОВОГО ЗАМОРАЖИВАНИЯ НА ПОТЕРИ ПРИ РАЗМОРАЖИВАНИИ И СТРУКТУРНО-МЕХАНИЧЕСКИЕ ХАРАКТЕРИСТИКИ ГОВЯДИНЫ

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    Abstract The effect of conventional and shock freezing on thaw drip loss and firmness of beef meat was studied. The meat samples was frozen in conventional freezer at -18 °C and shock frozen meat samples reached -50 °C temperature. Drip loss was measured by weighing the meat sample during thawing. The firmness was performed with TA-XT Plus Texture Analyzer with the volodkevich bite jaws. The firmness score and thaw drip loss differences did not been recognized between conventional and shock freezing meat excluding 7th day.АннотацияИзучали влияние традиционного и шокового замораживания на потери сока при размораживании и жёсткость говядины. Образцы мяса были заморожены в традиционном морозильном аппарате при -18 °C, в то время как температура образцов мяса, подвергнутых шоковому замораживанию, достигала -50 °C. Потери вследствие вытекания сока измеряли путём взвешивания образца мяса во время размораживания. Определение жёсткости проводили на анализаторе текстуры TA-XT Plus Texture Analyzer с устройством Володкевича для тестирования силы резания. Не было установлено различий в жёсткости и потерях вследствие вытекания сока при размораживании между традиционным и шоковым замораживанием, за исключением седьмого дня

    Vyuziti histologickeho vysetreni masnych vyrobku pri vykonu veterinarniho hygienickeho dozoru

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    Histological examination belong to analytical methods for studying the meat product composition and proportion of individual components of animal and plant origin. The aim of this study is to evaluate the possibilities of histological examination methods for use in veterinary hygienic supervision of processing foodstuffs of animal origin. It is based on a study of microscopic structure of meat products, selection of suitable procedures for sample processing, and methods to prove some components which are important for the evaluation of the product. The obtained results are necessary for further applying exacting histochemical methods, and thus extending the spectrum of identified components in meat products, as well as the possibility of quantitative evaluations of results of histological of meat products. Results of histological examinations may be used to evaluate the quality of meat products, as well as the health safety of foodstuffs of animal origin. The histological examination is at present, one of the possibilities to prove meat products adulterationAvailable from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

    Kvalitativni a kvantitativni aspekty histologickeho vysetrovani masnych vyrobku.

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    Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

    THE EFFECT OF CONVENTIONAL AND SHOCK FREEZING ON DRIP LOSS AND TEXTURAL PARAMETERS OF BEEF MEAT

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    Abstract The effect of conventional and shock freezing on thaw drip loss and firmness of beef meat was studied. The meat samples was frozen in conventional freezer at -18 °C and shock frozen meat samples reached -50 °C temperature. Drip loss was measured by weighing the meat sample during thawing. The firmness was performed with TA-XT Plus Texture Analyzer with the volodkevich bite jaws. The firmness score and thaw drip loss differences did not been recognized between conventional and shock freezing meat excluding 7th day

    Effect of storage on content of theaflavins and thearubigins in oolong teas

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    Teaflawiny i tearubiginy, należące do grupy barwników flawonoidowych, mają duży wpływ na właściwości smakowe i barwę herbat fermentowanych. Celem pracy było określenie wpływu rodzaju opakowania, czasu, i warunków przechowywania na zawartość teaflawin i tearubigin w herbatach typu oolong. Herbaty przechowywano przez 12 miesięcy. Początkowa, średnia zawartość teaflawin wynosiła 0,30 g/100 g herbaty oolong, a tearubigin – 5,30 g/100 g herbaty. Po 3 miesiącach przechowywania nastąpiło statystycznie istotne (p ≤ 0,05) [-] zmniejszenie zawartości tearubigin (średnio do 4,04 g/100 g herbaty), a po 4 miesiącach zaobserwowano ubytek teaflawin – średnio do poziomu 0,20 g/100 g herbaty. Po 12 miesiącach przechowywania ubytek teaflawin wyniósł 76,66 %, a tearubigin – 59,24 %. Wykazano, że zawartość tych substancji podlegała mniejszym wahaniom w przypadku herbat przechowywanych w oryginalnych opakowaniach papierowych (torebka papierowa z wewnętrzną ochroną i folią na powierzchni) i metalowych. Ze względu na niestabilność barwników flawonoidowych najmniej korzystne były opakowania szklane i papierowe poddane działaniu promieniowania rozproszonego. Stwierdzono, że podczas przechowywania herbat nastąpiła w nich degradacja barwników, a czas i warunki przechowywania determinowały barwę herbaty oolong.Theaflavins and thearubigins, which belong to a group of flavonoid pigments, have a strong impact on the gustatory properties and the colour of fermented teas. The objective of the research study was to determine the effect of packaging type as well as storage time and conditions on the content of theaflavins and thearubigins in oolong teas. The teas were stored for 12 months. The initial mean content of theaflavins was 0.30 g/100 g of oolong tea, and of thearubigins: 5.30 g/100 g of tea. After 3 months of storage, a statistically significant (p ≤ 0.05) decrease in the content of thearubigins occurred (to 4.04 g/100 g of tea on average) and after 4 months, the reported level of the decreased content of theaflavins was 0.20 g/100 g of tea on average. After 12 months of storage, the decreased level of theaflavins was 76.66 % and of thearubigins: 59.24 %. It was proved that the content of those substances fluctuated less in the case of the teas stored in original paper packaging (paper bag with an inner protective layer and a foil on its surface) and in packaging of metal boxes. The glass and paper packaging exposed to stray light were the least beneficial owing to the instability of flavonoid pigments. It was found that during storage of the teas, a degradation of pigments occurred, and the storage time and conditions determined the colour of the oolong tea

    Physicochemical Characterization of Home-Made Soap from Waste-Used Frying Oils

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    The study aimed to describe the utilization of waste frying oils, originated mainly from households, in home-made soap production and to emphasize the advantages of soap biodegradation in comparison to biological treatment of oils. The physicochemical analyses of soaps were used to check the differences between the samples made of fresh and fried oils. Significant (p < 0.05) difference between the soaps made of fresh/fried olive oil pair was obtained, while the rapeseed sample pair did not differ significantly (p < 0.05). Malondialdehyde (MDA) exhibited notable differences with an increase from 1.94 μg/g to 2.33 μg/g for olive oil fresh/fried pair and from 3.43 μg/g to 4.10 μg/g for rapeseed–palm oil fresh/fried pair. The studies addressing the soap biodegradation process revealed that soaps are degrading up to four times faster than oils in waste processing plants. Literature data showed the syntrophic ways of soap degradation and degradation solely done by sulfate-reducing bacteria. Obtained results, same as literature data, indicated that soaps produced from fried plant oils represent acceptable products from the economic and environmental point of view. Soap production can be considered one of the possible ways toward reduction of waste oil disposal

    Fortified Cold-Pressed Oils: The Effect on Sensory Quality and Functional Properties

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    The aim of this study was to monitor sensory quality, stability, selected nutritionally interesting properties and their changes in cold-pressed oil blends after fortification with chia and sesame seeds and seed oils during repeated thermal treatments. Rapeseed (cv. Sidney) and sunflower (cv. Velox) seeds from the Czech Republic were used to produce cold-pressed oils, which were fortified with chia and sesame seeds and seed oils in the concentrations of 1% and 5%. In all oil blends, sensory evaluation (quantitative descriptive analysis and hedonic analysis) and chemical analyses (oxidation degree, hydrolytic stability, chlorophyll and carotenoid content) were carried out in order to perform separation of samples degraded by thermal treatment. Assessors representing consumers were able to differentiate between individual thermal treatments from the viewpoint of pleasantness. Interestingly, the overall pleasantness of all fortified oil samples was still acceptable until the second thermal treatment. On the other hand, the results of the study emphasized the problematic oxidation degree of cold-pressed oil blends. The fortification of cold-pressed oils with chia and sesame seeds and oils did not unambiguously lead to better stability during thermal treatment. The application of elevated temperatures during the culinary use of these types of products should be limited to only one thermal treatment since sensory and chemical changes occur after repeated heating

    Active Edible Films Fortified with Natural Extracts: Case Study with Fresh-Cut Apple Pieces

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    The main aim of the study was to prepare the edible films based on carrageenan/chitosan and incorporate them into the following matrices: the natural extracts of Clitoria ternatea, Brassica oleracea, and Ipomea batatas. The films were characterized by TPC (total polyphenols content), antioxidant activity, and textural properties. Experimentally produced films were added in the packaging of freshly cut apple pieces, and the apple pieces were dipped into the films produced from carrageenan and chitosan. The appearance of the samples was monitored, as were antioxidant activity and total polyphenol content. The intelligent properties of films were evaluated too. The polymer type used for the preparation had the highest impact on the prepared films, and CHLCZ (red cabbage extract—Brassica oleracea) featured the best antioxidant activity. The intelligent properties were slightly confirmed in samples with the addition of red cabbage. The main finding was that the coating of fresh-cut apples emphasized the possibility to use a carrageenan matrix with the addition of extracts. The samples immersed in this coating type showed higher antioxidant activity as well as a superior color when compared to that of chitosan coated apple samples
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