Search

The present study aimed to investigate the impact of temperature on the quality attributes, particularly lipid oxidation and phospholipid molecular species, of Tai Lake whitebait during hot-air drying. Fresh samples of Tai Lake whitebait were subjected to heat treatment and were dried at temperatures of 40, 50, 60, and 70 °C for 12 h. The results indicated significant and continuous increases in peroxide values (POV), thiobarbituric acid reactive substances (TBARS), and saturated fatty acids (SFA) contents during hot-air drying, but reductions in monounsaturated fatty acids (MUFA). During the hot-air drying process, the mass fraction of triacylglycerol (TAG) and phospholipid (PoL) decreased, while the fractions of diacylglycerol (DAG), monoacylglycerol (MAG) and free fatty acid (FFA) increased. Furthermore, the drying treatment led to a more pronounced reduction in Phosphocholine (PC) content compared to phoethanolamine (PE). A total of 17 phosphatidylcholines (PC), 18 phosphatidylethanolamine (PE), 7 phosphatidylinositol (PI), and 9 phosphatidylserine (PS) molecular species were identified. By comprehensively considering the drying time and quality attributes, 50 °C was selected the ideal temperature for drying. The findings of the investigation revealed that thermal drying significantly influenced the quality attributes and lipid oxidation of Tai Lake whitebait. The insights gained from this study are valuable for improving the drying process for Tai Lake whitebait and enhancing its overall quality. • Lipid oxidation of whitebait were significantly affected by hot-air-drying. • Lipid composition of the Tai Lake whitebait were analyzed comprehensively. • Phospholipid classes in lipid of Tai Lake whitebait was identified. • 50 °C was determined to be the ideal drying temperature for Tai Lake whitebait. [ABSTRACT FROM AUTHOR]

In this study, the effects of different packaging techniques (normal and nitrogen atmosphere, and vacuum packaging) and different storage temperatures (4 and 20 °C) on lipid oxidation in in-shell and kernel walnuts of 'Chandler' and 'Sebin' varieties stored for 12 months were investigated. Free fatty acid, peroxide, p -anisidine, conjugated diene and triene values, hexanal contents, and fatty acid compositions of the walnuts were periodically determined during storage. Free fatty acid values of the samples stored at 20 °C were higher than those stored at 4 °C. Peroxide values of all samples fluctuated during storage but the values determined at the end were higher than their initial values. The highest hexanal and p -anisidine values were observed in the kernels packaged under normal atmosphere and stored at 20 °C. No significant changes were observed in conjugated triene values of the samples. Fatty acid composition was most stable in in-shell walnuts stored at 4 °C. Hexanal contents of the samples stored at 4 °C and the ones packaged under nitrogen and vacuum were remarkably lower than those of the samples packaged under air and stored at 20 °C. As a result, the oxidation reactions were strongly limited in in-shell walnuts of both varieties when stored at 4 °C for 12 months. It was determined that the factors affecting the oxidation reactions in walnuts were in a sequence of storage temperature > presence of the shell > variety > packaging technique. • The shell is a natural protective barrier of walnut against oxidation. • Oil oxidation in walnut was effectively limited when stored in-shell at 4 °C. • Packaging technique did not have significant effect on oxidative stability. • Oxidation progress in walnut varied depending on the variety. [ABSTRACT FROM AUTHOR]

[Display omitted] • The evolution of volatiles in the lean and fat portions of bacon showed different patterns. • The aroma compounds were mainly provided by lean portion, and the optimal drying time was 24 h. • Eight key aroma compounds derived from different lipid fractions and fatty acids. • Linoleic acid was vital for the generation of key aroma compounds in non-smoked bacon. This study explored the evolution of key aroma compounds and their lipid precursors in the lean (LN) and fat (FT) portions of non-smoked bacon during hot air drying. The results showed that the LN portion contained most of the aroma compounds in the bacon (>88%). The volatile content of the FT portion increased as the drying time increased, whereas that of the LN portion reached a maximum within 24 h and then decreased. Based on the highest volatile contents (4889.48 ± 202.06 µg/kg) and sensory scores, 24 h was considered the optimal drying time. For key aroma compounds, hexanal and 2,3-octanedione were derived from free fatty acids and polar lipids. Notably, 1-octen-3-ol was generated only from polar lipids in the FT and LN portions. The 2-undecenal and (E, E)-2,4-decadienal were produced by the oxidation of neutral lipids in the FT portion. Dihydro-5-pentyl-2(3H)-furanone was derived from polar lipids in the LN portion. Altogether, these findings provide theoretical insights into improving the aroma of bacon by optimizing raw material selection and processing methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • Toasted wheat bran protects RP in oil better from oxidation than native wheat bran. • A high bran-to-oil ratio lowers the stabilisation of vitamin A by native wheat bran. • High vitamin A and oil levels limit vitamin A stabilisation by toasted wheat bran. • Toasting reduces the capacity of wheat bran to protect lipids from oxidation. • Vitamin A acts as a pro-oxidant when mixed with oil and toasted wheat bran. Wheat bran stabilises vitamin A (retinyl palmitate, RP) in oil during storage, but the stabilisation mechanism remains unknown. We here studied the effect of the concentration of RP in oil (0.1–2%) and of RP-enriched oil in the system (5–50%) on the RP retention during accelerated storage of systems with native and toasted wheat bran. Generally, toasted bran showed better RP stabilisation than native bran. After four weeks of storage, up to 65% RP was retained in toasted bran systems, whereas the RP retention for native bran was below 10%. For native bran, a higher oil-to-bran ratio and, thus, a lower wheat lipase level resulted in better RP retention. For toasted bran, combined high oil and high RP concentrations resulted in the lowest RP retention. We, therefore, conclude that wheat bran protects RP and lipids from oxidation. This protection is reduced by the pro-oxidative effect of RP, lipid oxidation and lipase. [ABSTRACT FROM AUTHOR]