Evolution of lipid characteristics and minor compounds in hazelnut oil based on partial least squares regression during accelerated oxidation process

Changes in physicochemical properties and lipid oxidation lead to the formation of mud on salted egg yolks during storage

Salted egg yolk (SEY) becomes easily "muddy" during storage, leading to a decrease in the quality of salted eggs. The mechanism of SEY mudding was studied in this paper. The results showed that SEY hydrogen proton binding decreased, and SEY water and lipid fluidity increased during storage. In addition, the degree of lipid oxidation and monounsaturated fatty acids in salted egg yolk lipids (SEYL) increased, and primary oxidation products and secondary oxidation products were formed. Moreover, the structure of SEY was degraded to release lipids and proteins, and these proteins and lipids were re-emulsified to form new aggregates. Finally, by PLS-DA modeling analysis, it was found that the content of ω-3 polyunsaturated fatty acids and phospholipids changed significantly after SEY became muddy. These results suggest that the muddiness of SEY can primarily be attributed to higher fluidity and protein-lipid re-emulsification, and secondarily to the oxidation of SEYL.

An Efficient Deacidification Process for Safflower Seed Oil with High Nutritional Property through Optimized Ultrasonic-Assisted Technology

Safflower seed oil (SSO) is considered to be an excellent edible oil since it contains abundant essential unsaturated fatty acids and lipid concomitants. However, the traditional alkali-refined deacidification process of SSO results in a serious loss of bioactive components of the oil and also yields massive amounts of wastewater. In this study, SSO was first extracted by ultrasonic-assisted ethanol extraction (UAEE), and the extraction process was optimized using random centroid optimization. By exploring the effects of ethanol concentration, solid−liquid ratio, ultrasonic time, and the number of deacidification times, the optimum conditions for the deacidification of safflower seed oil were obtained as follows: ethanol concentration 100%, solid−liquid ratio 1:4, ultrasonic time 29 min, and number of deacidification cycles (×2). The deacidification rate was 97.13% ± 0.70%, better than alkali-refining (72.16% ± 0.13%). The values of acid, peroxide, anisidine and total oxidation of UAEE-deacidified SSO were significantly lower than those of alkali-deacidified SSO (p < 0.05). The contents of the main lipid concomitants such as tocopherols, polyphenols, and phytosterols in UAEE-decidified SSO were significantly higher than those of the latter (p < 0.05). For instance, the DPPH radical scavenging capacity of UAEE-processed SSO was significantly higher than that of alkali refining (p < 0.05). The Pearson bivariate correlation analysis before and after the deacidification process demonstrated that the three main lipid concomitants in SSO were negatively correlated with the index of peroxide, anisidine, and total oxidation values. The purpose of this study was to provide an alternative method for the deacidification of SSO that can effectively remove free fatty acids while maintaining the nutritional characteristics, physicochemical properties, and antioxidant capacity of SSO.