Whey proteins and oligomeric proanthocyanidins have nutritional value and are widely used in combination as food supplements. However, the effect of the interactions between proanthocyanidins and whey proteins on their stability has not been studied in depth. In this work, we aimed to characterize the interactions between β-Lactoglobulin (β-LG) and α-lactalbumin (α-LA) and oligomeric proanthocyanidins, including A1, A2, B1, B2, B3, and C1, using multi-spectroscopic and molecular docking methods. Fluorescence spectroscopic data revealed that all of the oligomeric proanthocyanidins quenched the intrinsic fluorescence of β-LG or α-LA by binding-related fluorescence quenching. Among the six oligomeric proanthocyanidins, A1 showed the strongest affinity for β-LG (Ka = 2.951 (±0.447) × 104 L∙mol−1) and α-LA (Ka = 1.472 (±0.236) × 105 L∙mol−1) at 297 K. β-LG/α-LA and proanthocyanidins can spontaneously form complexes, which are mainly induced by hydrophobic interactions, hydrogen bonds, and van der Waals forces. Fourier-transform infrared spectroscopy (FTIR) and circular dichroism spectroscopy showed that the secondary structures of the proteins were rearranged after binding to oligomeric proanthocyanidins. During in vitro gastrointestinal digestion, the recovery rate of A1 and A2 increased with the addition of WPI by 11.90% and 38.43%, respectively. The addition of WPI (molar ratio of 1:1) increased the retention rate of proanthocyanidins A1, A2, B1, B2, B3, and C1 during storage at room temperature by 14.01%, 23.14%, 30.09%, 62.67%, 47.92%, and 60.56%, respectively. These results are helpful for the promotion of protein–proanthocyanidin complexes as functional food ingredients in the food industry.
Oligo-ethylene/propylene glycol ethyl ether acetate (oligo-EGEEA and oligo-PGEEA) used to be synthesized in a two-step process with acetic acid as starting material. This paper describes a one-step production process catalyzed by the Al-Mg composite oxide, achieved by alkoxylation of ethyl acetate directly. Aiming at a narrow adduct distribution to get high product selectivity of mono-derivatives, the alkoxylation parameters, such as the Al/Mg molar ratio of the catalyst, molar ratio of reactants, temperature, initial reaction pressure, and reactant feed rate were investigated. The highest content of mono-and di-derivatives in the products was: w (oligo-EGEEA) = 73.8%, w (oligo-PGEEA) = 87.9%, respectively. The product selectivity of mono-EGEEA was decreased by only 5% after reusing the catalyst for ten runs. A 1.26-fold increase in the yield of mono-PGEEA was achieved by treating the catalyst surface with alcoholic potash. 2006 Society of Chemical IndustryKeywords: alkoxylation; ethyl acetate; adduction; composite oxide; adduct distribution; ethylene oxide INTRODUCTION Oligo-ethylene glycol ethyl ether acetate and oligopropylene glycol ethyl ether acetate (oligo-EGEEA and oligo-PGEEA), especially their mono-and diderivatives, are excellent solvents for dyes, paints and pigments. They used to be synthesized in a two-step process, which was (using alcohol, carboxylic acid or ester, and ethylene oxide (EO)/propylene oxide (PO) as reactants) carried out through etherealization of the alcohol, followed by esterification or transesterification. A one-step synthesis of alkoxylated fatty acid ester has been reported 1,2 in which zirconium chloride and/or aluminum chloride were used as main catalyst and co-catalyzed by triethylamine. Hama et al.
Neuroinflammation plays a significant role in the aging process and the pathophysiology of neurodegenerative diseases, such as Alzheimer’s disease. Accordingly, possible therapeutic strategies aimed at anti-inflammatory effects may be beneficial to brain health. Walnut kernels contain large quantities of unsaturated fatty acids, peptides, and phenolic compounds that have anti-inflammatory effects. The long-term intake of walnuts has been found to improve cognitive function and memory in rats and humans. However, the modulatory effect of walnuts on neuroinflammation has received much less attention. This review focuses on the potential influence and main regulating mechanisms of walnuts and their active ingredients on neuroinflammation, including the regulation of microglia activation induced by amyloid β or lipopolysaccharides, inhibition of peripheral inflammation mediated by macrophages, reduction in oxidative stress by decreasing free radical levels and boosting antioxidant defenses, and control of gut microbes to maintain homeostasis. However, the majority of evidence of the beneficial effects of walnuts or their components on neuroinflammation and neurodegeneration comes from experimental work, whereas evidence from clinical studies on the beneficial effects is scarcer and less conclusive. This review aims to provide new insights into the neuroinflammation-regulating mechanisms and natural active ingredients of walnuts and the development of walnut-based functional foods for the alleviation of neurodegenerative diseases.
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