The purpose of this paper was to investigate the effect of high-intensity ultrasonication (HIU) pretreatment before enzymolysis on structural conformations of walnut protein isolate (WPI) and antioxidant activity of its hydrolysates. Aqueous WPI suspensions were subjected to ultrasonic processing at different power levels (600–2000 W) and times (5–30 min), and then changes in the particle size, zeta (ζ) potential, and structure of WPI were investigated, and antioxidant activity of its hydrolysates was determined. The particle size of the particles of aqueous WPI suspensions was decreased after ultrasound, indicating that sonication destroyed protein aggregates. The ζ-potential values of a protein solution significantly changed after sonication, demonstrating that the original dense structure of the protein was destroyed. Fourier transform infrared spectroscopy indicated a change in the secondary structure of WPI after sonication, with a decrease in β-turn and an increase in α-helix, β-sheet, and random coil content. Two absorption peaks of WPI were generated, and the fluorescence emission intensity of the proteins decreased after ultrasonic treatment, indicating that the changes in protein tertiary structure occurred. Moreover, the degree of hydrolysis and the antioxidant activity of the WPI hydrolysates increased after sonication. These results suggest that HIU pretreatment is a potential tool for improving the functional properties of walnut proteins.

Intramuscular fat (intramuscular fat, IMF) is one of the important traits of pork quality. How to reasonably improve the intramuscular fat content is the most focus researchers. Some possible regulation of intramuscular fat deposition of candidate genes to cause the attention of people. The objective of this study was to elucidate the relationship between peroxisome proliferator-activated receptor γ (PPARγ) and adipose differentiation-related protein (ADRP) mRNA expression and intramuscular fat (IMF) deposition in the muscle tissue of three breeds of pig: Laiwu (LW), Lulai Black (LL), and Large White (LY). qPCR analysis of the PPARγ and ADRP genes in the three breeds of pig revealed PPARγ and ADRP mRNA expression profiles of LW > LL > LY and LL > LW > LY, respectively. PPARγ mRNA expression was significantly and positively correlated with IMF deposition (p < 0.05). There were significant correlations between PPARγ and ADRP mRNA expression levels (p < 0.01). These results suggest correlations between PPARγ and ADRP in fat deposition and regulation in pigs, PPARγ gene may be a main effector of IMF content and play an important role during adipocyte differentiation in pigs, thereby providing new information to further elucidate molecular mechanisms associated with intramuscular fat deposition in Laiwu pigs and provides new data for further molecular studies of mechanisms underlying intramuscular fat deposition in human obesity. The continued elucidation of specific genetic mechanisms between PPARγ and ADRP warrants further studies.

Fat deposition in muscle includes intramuscular fat (IMF) and intermuscular fat. IMF content is an index of pork quality; however, because IMF content is difficult to measure in vivo in young animals, conventional breeding for IMF content is difficult to carry out. The mechanism and progression of animal fat deposition is not well understood, and there are currently no effective control methods. In this study, using Laiwu and large white pigs as the research subjects and RNA sequencing technology, we analyzed the genetic mechanism of animal fat deposition in pigs. Specifically, we analyzed the features of lncRNAs and their potential target genes. We obtained 464 million clean reads, from which 907 lncRNAs were identified. The cis and trans analysis identified target genes, including genes that were upregulated (286) and downregulated (621) in the fatty and lean pigs. ENSSSCG00000008692_ADD1, ENSSSCG00000023124_ADD1 and ENSSSCG00000005918_DGAT1 were validated as target genes of the lncRNAs and were shown to be closely related to fat deposition. These results provide a basis for studying the different metabolic lncRNA expression of IMF deposition. In addition, as the valuable model animal to study the mechanisms of obesity, pigs may represent a new avenue for studying human obesity.