177,016 research outputs found
Recupero e valorizzazione dei sottoprodotti della pesca come fonti di acidi grassi polinsaturi n-3
No full textActivity of two different polyglucosamines, L112((R)) and FF45((R)), on body weight in male rats
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Evoluzione compositiva dell’olio durante il processo di frittura
No full textBlue fish is the main dietary source of long chain polyunsaturated omega-3 fatty acids, which are known to be among the fatty acids most prone to oxidative degradation. The deep-frying process is therefore critical in the preparation of seafood products. On the other hand, deep-frying is a very popular method of cooking fish and is particularly appreciated by the consumer, as it is a quick procedure and leads to a nourishing and filling food, due to the absorption of oil by the fried food. The extremely pleasant texture of a fried product is of primary importance, thanks to the crispy properties, partially due to the evaporation of free water. This results in the formation of a surface crust containing Maillard reaction products with well appreciated sensory characteristics.
The conditions of deep frying (oil quality and origin, temperature and duration of frying, re use of frying oils from previous treatments) represent a critical factor for the formation of compounds with anti nutritional properties in the fried fish.
The aim of this study was the evaluation of the influence of the operating parameters in the case of domestic frying on the quality of both fresh oil, oil subjected to frying and sardines (Sardina pilchardus) used as raw material in the process. The main changes produced in oils and fish during the frying process were monitored.
Three types of oils were obtained from local shops: extra virgin olive oil, conventional sunflower oil and high oleic sunflower oil. The frying temperature was 160° C. Ten fishes for each experimental point were fried for 5 min in an electric fryer, capacity 2 L, in a closed environment. The fried fish was sampled after the following frying time intervals: 10 min, 30 min, 1 h and 2 h.
Afterwards, deep frying was carried out with the same frying oils and the same operating conditions, but using the residual oil from the previous test, which was performed 24 hours before. A third test was performed by re using the residual frying oil which had been stored into a closed bottle and kept at room temperature in the dark for one week. The determinations made on the frying oils were the forced oxidation test (Rancimat test), free acidity, peroxide number, spectrophotometric parameters and fatty acid composition. The fried fish were analysed to determine the fat and water content, the fatty acid composition and the composition of the molecular species of phosphatidylcholin
Stereospecific analysis of triacylglycerols in mare's milk [Indagine sulla struttura trigliceridica del latte di giumenta]
No full textFatty acids composition of mare milk triacylglycerols (TGs) was studied at three different lactation stages. Stereospecific analysis of TGs was carried out with Chemical deacylation and enzymatic hydrolysis to determine the fatty acids distribution on the glycerol backbone as the TG structure are of importance when considering the biological functions, the nutritional value as well as the echnological properties of milk lipids. Milk samples showed a high content of EFA, about 25% of the total fatty acid composition. In all considered lipid fraction saturated fatty acids (SFA), especially about 50% to 70% of C8:0 and C10:0, were prevalently esterified at the sn-2 position. Unsaturated fatty acids (UFA) occupied essentially the sn-(1,3) position; on average only 21.2% of C18:3ω3 and 19% of C18:2 were localized at the sn-2 position
A regulatory mutant of Hansenula polymorpha exhibiting C1-peroxisomes under glucose growth
No full textStereospecific analysis of triacylglycerols in camel (Camelus dromedarius) milk fat
No full textIn the lipid fraction of camel (Camelus dromedarius) milk the percentage of saturated fatty acids (SFAs) was 62.8% with a content of palmitic acid of 28.5%. The unsaturated fatty acid (UFA) fraction was dominated by oleic and palmitoleic acids. Enzyme digestion and chemical degradation methods were used to determine the intramolecular fatty acid (FA) composition and then the intermolecular FA distribution in the three sn-positions of the triacylglycerols of the camel milk. FAs showed a specific preference for a particular position: in all samples studied, SFAs were prevalently esterified in the sn-2 position, while UFAs occupied mainly the sn-1 and sn-3 position. As the carbon chain lengthened from 8 to 16 the percentages of SFAs decreased in the sn-2 position and increased in the outer positions. Such data indicated that the length of the carbon chain could be a discriminating factor in the acylation process of SFAs
Aspetti agronomici e prospettive di valorizzazione della corilicoltura nel Lazio
No full textVengono analizzate la situazione della coltura del nocciolo in Italia, le principali i problematiche e le tecniche di produzione. Si riportano alcuni risultati della ricerca finalizzati al miglioramento della tecnica colturale
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