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Celem badań było określenie aktywności przeciwutleniającej ekstraktów z kopru, podbiału, rozmarynu, skrzypu, szałwii i tymianku dodawanych do lipidów wyekstrahowanych ze świeżej i przechowywanej w warunkach zamrażalniczych tkanki mięśni piersiowych kurcząt i indyków. Okres zamrażalniczego przechowywania tkanki wynosił 6 miesięcy, a temperatura -25ºC. Aktywność przeciwutleniajacą ekstraktów roślinnych w stosunku do lipidów określano na podstawie zmian kolorymetrycznych prób w czasie ogrzewania od 10 do 60 min w temp. 50°C. Stwierdzono, że najlepsze właściwości ochronne wobec lipidów wyekstrahowanych ze świeżej tkanki mięśni piersiowych kurcząt wykazały ekstrakty kopru i podbiału, a w przypadku lipidów pochodzących z mięśni indyków były to ekstrakty z: podbiału, rozmarynu i skrzypu. Aktywność przeciwutleniająca analizowanych ekstraktów roślinnych dodawanych do lipidów pozyskanych z tkanki mięśni piersiowych kurcząt i indyków po jej zamrażalniczym przechowywaniu uległa osłabieniu. W tym przypadku właściwości przeciwutleniające w stosunku do lipidów wyekstrahowanych z tkanki mięśniowej indyków zachowały tylko ekstrakty kopru, rozmarynu i tymianku, a kurcząt - żaden z analizowanych ekstraktów. Uzyskane wyniki dowodzą, że przeciwutleniacze zastosowane do ochrony lipidów pozyskanych z mięśni piersiowych drobiu, po wcześniejszym zamrażalniczym przechowywaniu tkanki, cechują się obniżoną aktywnością przeciwutleniającą.
Content of hydroperoxides, secondary products of oxidation, dienes and trienes was analysed in a minced muscle tissue of Baltic herring treated with white mustard, while stored at -25°C.
Background. Natural antioxidants become increasingly important in fish processing and particularly in the preservation phase of fish raw materials. Some of them can protect lipids, containing essential unsaturated fatty acids. The aim of the present study was to determine antioxidant properties of aqueous extracts of rosemary and sage, compared with the activity of BHA (butylated hydroxyanisole) and Endox in lipids of fresh Baltic fishes (herring, sprat, flounder) and those subjected to frozen storage at -25°C for 6 months. Materials and Methods. Antioxidant activity of the additives was determined based on β-carotene changes in fish lipids after 10, 20, 40, and 60 min of heating at 50°C. Results. The plant-origin extracts and the synthetic antioxidants used, inhibited most extensively β-carotene changes in the lipids of non-frozen herring. They were the least effective in non-frozen sprat lipids. The frozen storage lowered the antioxidant action of the additives in relation to β-carotene in lipids of herring and flounder, whereas in sprat lipids the antioxidants used, continued their protective action for β-carotene, during heating. Elongation of the heating time from 10 to 60 min increased the β-carotene losses and their pace followed the logarithmic scale. The activity of the antioxidants in fish lipids decreased along with the increase of polyunsaturated fatty acids (C20 : 5, C22 : 5, and C22 : 6) contents Conclusion. The antioxidant properties of plant-origin additives and synthetic antioxidants decreased along with the increased content on unsaturated fatty acids of fish lipids. Six-month-long frozen storage of the fish raw materials resulted in a decrease of the protective properties of the additives used, in relation to the lipids of Baltic herring and flounder. The best protective properties for lipids of flounder and sprat exhibited Endox, while aqueous extract of rosemary was the most effective in relation to sprat lipids.
Background. Cooling and freezing were used as one of the most important and widely used methods of fixation of the food. However, it must be stressed that low temperatures should not be applied to stock up bakery goods, but to improve production organisation, balance demand and supply, as well as to provide consumers with a wide range of fresh fish. Material and methods. Raw Atlantic herring was packed in polyethylene (PE) bags: in air or in vacuum and then frozen and stored at -25°C. The quality of fresh fish and of carcasses and fillets after 1, 2, 3 and 4 months of storage was estimated by determination of weight change, pH, moisture and fat content,hardness, cohesiveness, springiness, resilience, gumminess, and chewiness. Results. Weight of the air-packed herring samples decreased along with frozen storage time, due to changes in moisture content in the muscle tissue. The vacuum-packed raw material did not demonstrate weight changes. Moisture content was correlated with cohesiveness of the fish packed in air. Strong correlations were found between hardness and gumminess / chewiness regardless of the packing method, springness and pH / fat content of vacuum-packed fillets, and cohesiveness and springness / resilience of the vacuumpacked carcasses. Additionally, significant correlation coefficients were obtained between coherence and resilience for carcasses packed in air, as well as between gumminess and chewiness regardless of the packing method. Significant correlation occurred also between cohesiveness and resilience for carcasses packed in air, as well as between gumminess and chewiness regardless of the packing method. The packing method, as well as raw fish processing were found to have a major impact on cohesiveness and springiness, and in the case of carcasses also on resilience. No significant differences in hardness, gumminess and chewiness were found for samples obtained from different sections of the same fish, either fillets or carcasses. Significant differences were found in textural properties between the fresh and stored samples. Only hardness, gumminess and chewiness of fish samples did not show any significant changes throughout the storage period.
Generally, fruits are characterized by a short-term stability as a result of a fast running ripening process. The main aim of the research was to define the influence of kind of packaging on some physical changes of the bananas during frozen storage. The bananas were stored in Air (P), Vacuum (V) and Atmosphere Modified (MAP) in time three months in –25°C. Kinetics of texture changes was studied on a whole banana fruit and a vertical selection of banana. The texture properties can include several parameters: hardness, adhesiveness, springiness, cohesiveness, gumminess and chewiness. Texture measurements were made using TPA test. The whole banana fruit characterize with decrease such parameters as hardness, adhesiveness, gumminess and chewiness. Vertical selections of banana characterize with decrease such parameters as hardness, gumminess and chewiness. However, the growth of adhesiveness and cohesiveness succeeded. The results indicated that kind of packaging not influence on amplification banana fruits.
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