Food-derived peptides have good antioxidant activity and are highly safe for humans; consequently, there has been continuous growth in research on antioxidants, with potential applications in food, medicine, cosmetics, and other fields. Among food-derived peptides, walnut-derived peptides have attracted increasing attention as food-derived peptides rich in eight essential amino acids. This review summarizes the progress made in the development and identification of antioxidant peptides in walnut proteins. This article mainly describes the interaction between reactive oxygen species and cellular antioxidant products, modulation of enzyme content and activity, and regulation of the redox signaling pathways and analyzes the mechanisms of reduction in oxidative stress. Finally, the complex structure–activity relationships of walnut-derived peptides are analyzed based on their amino acid composition and secondary structure of the polypeptides. This review provides a theoretical basis for the production of walnut-derived antioxidant peptides and could help promote the development of the walnut industry.

Litsea cubeba is a characteristic woody oil resource in Hunan. As a solid waste of woody oil resources, Litsea cubeba kernels are rich in Litsea cubeba kernel oil with a carbon chain length of C10–12 fatty acid. In this work, aliphatic hydroxamic acids (AHAs) with carbon chain lengths of C10–12 were prepared from Litsea cubeba kernel oil via methylation and hydroximation reactions. The adsorption and hydrophobicity mechanism of AHA towards wolframite was explored by contact angle, zeta potential, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The flotation results demonstrated that AHA was a superior collector than the traditional collector such as benzoyl hydroxamic acid (BHA). Zeta potential and contact angle results have shown that AHA was adsorbed on the surface of the Fe(III)-activated wolframite in its anionic form, which significantly improved the surface hydrophobicity of wolframite. FTIR and XPS revealed that AHA was chemically adsorbed on the surface of Fe(III)-activated wolframite in the form of a five-member ring, which made the hydrophobic chain reach into the solution, come in contact with bubbles, and achieve flotation separation.

Phosphorus deficiency poses a significant challenge to plant growth and development, particularly in red soil. To alleviate this limitation, phosphorus-solubilizing bacteria (PSB) play a crucial role by converting insoluble phosphates present in the soil into soluble forms that are accessible to plants. Cornus wilsoniana Wangerin is a representative oil crop cultivated in red soil, holding a prominent position within China’s forestry economic system. Consequently, it is essential to develop highly stable microbial phosphorus enhancement strategies to manage agricultural phosphorus in red soil regions, thereby maintaining the available phosphorus content necessary for the production of C. wilsoniana. In this study, the application of Streptomyces misionensis SwB1 bacterial suspension to the rhizosphere of C. wilsoniana significantly increased the content of various phosphorus fractions (H₂O-P, NaHCO₃-P, NaOH-P, HCl-P) in red soil, with NaHCO₃-P content increasing by 4.97 times and NaOH-P content by 3.87 times. Additionally, the genome of S. misionensis SwB1 contains 25 phosphorus-solubilizing genes, 13 nitrogen-fixing genes, 17 siderophore production genes, and 11 indole-3-acetic acid (IAA) production genes, indicating its potential for enhancing nutrient availability. Comparative genomic analysis of 15 strains belonging to five species of Streptomyces revealed that S. misionensis SwB1 possesses an extensive genetic repertoire and complete gene clusters associated with phosphorus solubilization. Furthermore, five phosphorus solubilization pathways of S. misionensis SwB1 were summarized: the Pst system, Pit system, siderophore transport, phosphatase synthesis, and organic acid synthesis. Ultimately, the inoculation of S. misionensis SwB1 significantly enhanced the growth and biomass accumulation of C. wilsoniana at the seedling stage, evidenced by an increase in fresh weight by 81.44%, a rise in net photosynthetic rate by 18.51%, and a surge in the number of root tips by 36.24%. Taken together, our findings support a sophisticated multi-pathway bacteria phosphorus solubilization approach and identified a highly efficient phosphorus-solubilizing strain, S. misionensis SwB1, which has the potential to become a microbial fertilizer.

In this paper, a novel collector dihexyl (2-(hydroxyamino)-2-oxoethyl) phosphonate (DHHAOEP) was synthesized and used as a flotation collector to separate scheelite from quartz. Micro-flotation experiments demonstrated that DHHAOEP can effectively separate scheelite from quartz within a pH range of 6–9. Artificial mixed ores flotation experiments revealed that at a pH of approximately 8 and a DHHAOEP concentration of 8 × 10⁻⁵ mol/L, the flotation recovery of scheelite reached 73% with a grade of 54%. The contact angle and Zeta potential measurements showed that the addition of DHHAOEP caused a positive shift in the zeta potential and enhanced the surface hydrophobicity of scheelite. The FTIR, XPS, and DFT analyses further elucidated that DHHAOEP anchored on the scheelite surface through the bonding reaction between its -C(=O)-NHOH moiety and WO₄²⁻ or Ca active sites on the scheelite surface, forming a five-membered ring. Meanwhile, the existence of the P=O group makes the distance between oxygen atoms in -C(=O)-NHOH very close to that in WO₄²⁺, which is beneficial to the reaction. The present work aims to develop a novel flotation collector with multi-functional groups to enhance scheelite recovery efficiency and selectivity.

Herein, diacylglycerol (DAG) was prepared from Swida wilsoniana fruit oil by a two-step enzymatic process, and the quality of crude Swida wilsoniana fruit oil (Crude oil), refined Swida wilsoniana fruit oil (Refined oil), DAG oil derived from crude oil (Crude oil-DAG), and DAG oil derived from refined oil (Refined oil-DAG) were compared and evaluated. The results showed that Lipozyme® RM IM enzyme exhibited the best hydrolysis effect in the hydrolysis reaction, while Novozym® 435 enzyme had a lower reaction energy barrier and a faster esterification catalytic rate in the esterification reaction, yielding a DAG content of up to 72.99%. Quality analysis showed that the physical and chemical indicators of the four oils all met the national standards, refining and enzymatic reactions can affect the tocopherol content, oxidative stability and flavor components of oils. The tocopherol content and oxidative stability in the crude oil were the best, and the volatile flavor substances of the crude oil and its DAG were richer. The research confirmed that the crude Swida wilsoniana fruit oil is an ideal raw material for the preparation of DAG, and the obtained DAG has excellent comprehensive quality.