68 research outputs found
Evaluation of frying oil subjected to prolonged thermal treatment: volatile organic compounds (VOC) analysis by DHS-HRGC-MS and 1H-NMR spectroscopy
Comparision of the frying performance of olive oil and palm superolein
Deep-fat frying is an important method of food preparation in wich foods are immersed in hot oil. Repeated use of frying oils is a common practice and in the presence of atmospheric oxygen it produces various undesiderable reactions in used oils. Stable frying oils usually required low linolenic acid (LnA < 3%). The aim of this study was to establish the behaviour of palm superolein (PSO) (OA 45%, LA 12.5%, LnA 0.2%) and olive oil (OO) during repeated, discontinous deep frying of French fries. The behaviour of the oils under controlled heating conditions was also studied by maintaining all of the process variables the same as those in deep frying except that there was no food in the oil. The PSO selected to be tested in this study may represent an alternative to OO as a frying medium. Although PSO presented a faster increase in some oxidation indices, such as free acid and total polar compounds, for other indicators, PSO showed better behaviour than OO (less formation of C8:0 and lower peroxide value)
Effect of tomato by-products in the diet of Comisana sheep on composition and conjugated linoleic acid (CLA) content of milk fat
To evaluate the effect of supplementing the diet of Comisana sheep with by-products from industrial tomato manifacture on the composition and conjugated linoleic acid (CLA) content of milk fat, two groups of 50 ewes each were fed either total mixed ration standard (TMRS) or total mixed ration with added tomato by-products (TMRA). Milk fat composition was determinated by HRGC. The milk fat content for animals fed the TMRA diet increased by 6,41% aafter six weeks, compared with the animals fed the TMRS diet. The CLA content in the milk fat for the group of animal fed the TMRA diet was 19,8% higher than for those fed the TMRS diet. The fatty acid composition showed an increase in the amount of PUFA; the n-3:n-6 ratio increased by 13% in the milk from sheep fed with the TMRA diet
Ricerca del grano tenero in miscela con il duro negli sfarinati e nelle paste variamente essiccate
Il riconoscimento dell'uso del grano tenero nella produzione della pasta alimentare si basa sull'analisi gas cromatografica deli esteri degli steroli previo isolamento della frazione lipidica. Il metodo consente di calcolare la percentuale di grano tenero utilizzato sia negli sfarinati sia nelle paste
Determinazione del carvacrolo mediante HRGC-MS/FID nell'orata (Sparus aurata) di acquacoltura
Le proprietà antimicrobiche del carvacrolo sono state ampiamente descritte soprattutto sulla base di osservazioni in vitro. L’ampia diffusione “zootecnica” di Sparus aurata ha determinato in questi ultimi decenni il diffondersi di patologie batteriche come la pasteurellosi e la vibriosi. La sperimentazione è stata condotta per 45 giorni su orate (Sparus aurata) del peso medio di 150 g la cui razione alimentare giornaliera è stata incorporata con l’1% di carvacrolo, e su orate alimentate con il mangime base nello stesso periodo (gruppo controllo). La frazione lipidica è stata estratta dal muscolo mediante metodo di Folch modificato. L’identificazione del carvacrolo è stata effettuata via HRGC-MS. L’analisi quantitativa è stata valutata nelle stesse condizioni cromatografiche ma con detector a ionizzazione di fiamma (FID) in presenza di standard interno (n-dodecanolo). La procedura ha consentito il recupero del 98,97% circa del carvacrolo con un limite di rilevabilità pari a 0,5 ppm
Rapid determination of esterified glycerol and glycerides in triglycerides fats and oils by means of periodate method after transesterfication
The paper describes an accurate method to determine esterified glycerol in the glycerides edible fats and oils and in general in all triglycerides fats and oils
Proteomic study of muscle sarcoplasmic proteins using AUT-PAGE/SDS-PAGE as two-dimensional gel electrophoresis
The conversion of muscle to meat in pig involves mainly proteolysis of myofibrillar proteins, which undergo notable changes since early stage of rigor mortis, even after 48 h post mortem. The tenderness of meat has been thoroughly investigated to understand the biochemical mechanisms, which influence texture and flavour development as well as the technological parameters and hence meat quality. Cytoplasmic proteolytic calcium dependent enzymes, named -and m-calpains, which act in the early stages of rigor mortis, significantly contribute to tenderization weakening myofibrils. These enzymes, however, act for fewdays because they are specifically inhibited by calpastatin and by pH lowering. However, when pH falls to about 5.0, proteolytic activity on muscle proteins is continued by longer acting lysosomal proteinase, cathepsins [3,7–9]. Post mortem proteolysis also causes relevant changes in sarcoplamic protein fraction, which represent the water soluble fraction (quantitatively about 30–35%) of meat total protein, and the involved proteins has already been identified by proteomic-based studies. Recent investigations have demonstrated that the most commonly found Lactobacillus species in dry fermented meats are able to hydrolyse myofibrillar and sarcoplasmic muscle proteins in vitro.The most abundant sarcoplasmic proteins, as mixture of basic polypeptides with a narrow spread range of molecular masses, represented an excellent model to test our analytical technique and to delineate its capabilities. In the present study, we compared 2D AUT-PAGE/SDSPAGE maps of water-soluble proteins extracted from fresh meat and from dry-cured ham, a non fermented product, from “Naples-type” salami, a microbiologically fermented product, and from “Coppa”, a typical semi-fermented product. Electrophoretically separated proteins have been identified by MALDI-ToF mass fingerprinting
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