Panax ginseng C. A. Meyer (ginseng) is a medicinal plant widely used for promoting longevity. Recently, homogalacturonan (HG) domain-rich pectins purified from some plants have been reported to have anti-aging-related activities, leading us to explore the longevity-promoting activity of the HG pectins from ginseng. In this study, we discovered that two of low methyl-esterified ginseng HG pectins (named as WGPA-2-HG and WGPA-3-HG), whose degree of methyl-esterification (DM) was 16 % and 8 % respectively, promoted longevity in Caenorhabditis elegans. Results showed that WGPA-2-HG/WGPA-3-HG impaired insulin/insulin-like growth factor 1 (IGF-1) signalling (IIS) pathway, thereby increasing the nuclear accumulation of transcription factors SKN-1/Nrf2 and DAF-16/FOXO and enhancing the expression of relevant anti-aging genes. BLI and ITC analysis showed that the insulin-receptor binding, the first step to activate IIS pathway, was impeded by the engagement of WGPA-2-HG/WGPA-3-HG with insulin. By chemical modifications, we found that high methyl-esterification of WGPA-2-HG/WGPA-3-HG was detrimental for their longevity-promoting activity. These findings provided novel insight into the precise molecular mechanism for the longevity-promoting effect of ginseng pectins, and suggested a potential to utilize the ginseng HG pectins with appropriate DM values as natural nutrients for increasing human longevity.

In order to improve the esterification efficiency of the enzymatic synthesis of l-ascorbic acid palmitate, the substrate analogue imprinting of the Aspergillus niger lipase-catalyzed esterification process was studied. Oleic acid was selected as the imprinting molecule, oleic acid imprinting immobilized lipase was prepared at pH 8.0, 0.1 g oleic acid, 1.5 mL of 95 % ethanol, and 0.1 g Tween-20. Through solubilization and supersaturation of Vitamin C, the reaction concentration of Vitamin C reached 5.00 % (m/v) in dioxane with 93.99 % esterification rate and 110.72 g/L of product concentration. Moreover, the Vitamin C reaction concentration can reach 8.00 % by using staged substrate feeding, and the esterification rate and product concentration of esterification after 28 h was 156.34 g/L and 82.96 %. Besides, the imprinting-induced conformational changes in enzyme proteins was characterized by fluorescence and infrared spectroscopy. This method provides a pathway for enzymatic production of l-ascorbic acid palmitate.

High methyl-esterified citrus pectin (HMCP) is often used as a thickness in food products and is considered a poor emulsifier, especially in neutral pH solutions. Our previous findings show that the emulsifying capacity of HMCP could be significantly enhanced by calcium cations. Besides, the pH of the solution decreased in the presence of calcium cations. However, the impact of solution pH on HMCP emulsifying capacity in the presence of calcium cations is unclear. In this study, the pH of the HMCP solution was adjusted from 3.00 to 8.00 before adding calcium cations. The solution properties and emulsifying properties were analyzed in light of the existence of calcium cations. The results showed that the pH of the HMCP solutions decreased after bringing calcium cations into them. Calcium cations could change the solution rheological properties, particle size distributions and morphologies, and the particle microenvironmental hydrophobic areas in HMCP solutions while increasing the pH of HMCP solutions, contributing to improving the emulsifying capacity of HMCP. HMCP had the best emulsifying ability when the pH of the HMCP solutions was kept at a neutral level. This research gives us new ideas to adjust the emulsifying property of HMCP.

Partial acylglycerols are valued for their emulsifying and stabilizing properties, yet precise green synthesis remains challenging due to low yield and selectivity. This study aimed to elucidate the \"lipase selectivity-substrate structure-product composition\" relationship to enhance the yield of targeted partial acylglycerol. The results showed that lipase exhibited a greater selectivity towards fatty acids with shorter chain lengths and higher unsaturation. Hydroxyl donors also affected the esterification process, with the enzyme-acyl complex exhibiting selectivity towards hydroxyl donors as follows: glycerol > monoacylglycerol > diacylglycerol. Substrate ratio significantly influenced enzymatic reactions; a 10:1 ratio favored triacylglycerol formation (>80 %), while a 1:1 ratio produced > 90 % partial acylglycerols. Molecular docking simulations revealed that substrates primarily interacted with lipase through hydrogen bonding and hydrophobic interactions. A comprehensive understanding of lipase selectivity patterns could facilitate the design of more efficient reaction systems, enabling the conversion of basic lipid resources into desired high value-added products.

Aiming to contribute to the current knowledge on the impact of reaction conditions on the chemical structure and target properties of starch citrates, in the current contribution different corn starch citrates were prepared by manipulation of reaction time, temperature and citric acid concentration. Modified starches were characterized in terms of chemical structure, morphology, crystallinity, swelling power and resistant starch content. For the first time, total substitution, crosslinking and monosubstitution degrees were quantitatively determined; and the relationship among final chemical structure, reaction conditions and target starch citrates properties was comprehensively analyzed. Products with total substitution values in the range of 0.075-0.24, crosslinking degrees in the 0.005-0.11 interval, and monosubstitution extents within the 0.05-0.12 range, were produced. By proper selection of reaction conditions products with almost 100 % of resistant starch were obtained. Results evidenced that starch citrates properties (mainly swelling power and RS content) depend on both chemical structure and the reaction conditions employed. Actually, the reaction temperature set (120 °C or 150 °C) proved to play a determinant role in the final products properties as evidenced from starch citrates with similar chemical structure and substantially different swelling and digestibility properties.

Grape seed proanthocyanidin (GSP), as a natural antioxidant, has great potential to be developed into a lipid-lowering agent, but its low lipophilicity and stability greatly limit its application. In this study, an enzymatic esterification strategy was developed to introduce fatty acid chains into GSP, resulting in the successful synthesis of a series of new GSP derivatives. The results showed that up to 85% conversion of GSP and 35% TAG inhibition rate of GSP derivatives were achieved. The structures of GSP derivatives were identified by UPLC-MS/MS, and seven derivatives were confirmed as catechin-3\'-O-laurate, epicatechin-3\'-O-laurate, epicatechin gallate-3″,5″-di-O-laurate, epicatechin gallate-3\',3″,5″-tri-O-laurate, procyanidin B1-3\',3″-di-O-laurate, procyanidin B2-3\',3″-di-O-laurate and procyanidin C1-3\',3″,3‴-tri-O-laurate by NMR. GSP derivatives exhibited higher inhibitory effects on lipid accumulation, intracellular TAG and TC than parent GSP. These results indicate that GSP derivatives have potential as lipid-lowering agents for utilization in the food industry.

This work evaluated structured lipids (SLs) through chemical and enzymatic interesterification (CSLs and ESLs). Blends of soybean oil and peanut oil 1:1 wt% were used, with gradual addition of fully hydrogenated crambe to obtain a final behenic acid concentration of 6, 12, 18, and 24 %. Chemical catalysis used sodium methoxide (0.4 wt%) at 100 °C for 30 min, while enzymatic catalysis used Lipozyme TL IM (5 wt%) at 60 °C for 6 h. Major fatty acids identified were C16:0, C18:0, and C22:0. It was observed that with gradual increase of hard fat, the CSLs showed high concentrations of reaction intermediates, indicating further a steric hindrance, unlike ESLs. Increased hard fat also altered crystallization profile and triacylglycerols composition and ESLs showed lower solid fat, unlike CSLs. Both methods effectively produced SLs as an alternative to trans and palm fats, view to potential future applications in food products.

Transthiolation (also known as transthioesterification) reactions are used in the biosynthesis of acetyl coenzyme A, fatty acids and polyketides, and for post-translational modification by ubiquitin (Ub) and ubiquitin-like (Ubl) proteins1-3. For the Ub pathway, E1 enzymes catalyse transthiolation from an E1~Ub thioester to an E2~Ub thioester. Transthiolation is also required for transfer of Ub from an E2~Ub thioester to HECT (homologous to E6AP C terminus) and RBR (ring-between-ring) E3 ligases to form E3~Ub thioesters4-6. How isoenergetic transfer of thioester bonds is driven forward by enzymes in the Ub pathway remains unclear. Here we isolate mimics of transient transthiolation intermediates for E1-Ub(T)-E2 and E2-Ub(T)-E3HECT complexes (where T denotes Ub in a thioester or Ub undergoing transthiolation) using a chemical strategy with native enzymes and near-native Ub to capture and visualize a continuum of structures determined by single-particle cryo-electron microscopy. These structures and accompanying biochemical experiments illuminate conformational changes in Ub, E1, E2 and E3 that are coordinated with the chemical reactions to facilitate directional transfer of Ub from each enzyme to the next.

The formation conditions and functional property differences of esterified starch (ES) and granular esterified-pregelatinized starch (EPS) synchronously prepared by octenyl succinic anhydride (OSA) modification remain unclear. In this study, we explored the formation conditions and physicochemical properties of ES and EPS after OSA modification. The modification temperature controlled the formation amount and time for both starch types during OSA modification. Compared to ES, EPS exhibited a higher degree of substitution, cold-water swelling power, water-absorption capacity and apparent viscosity in cold water. The structural characterization confirmed the molecular weight and short/long-range molecular order of ES and EPS decreased. Moreover, scanning electron microscopy indicated EPS retained its granular morphology. The X-ray diffraction patterns confirmed the presence of more starch-lipid complexes formed in EPS than in ES. This study provides a novel method for preparing esterified and granularly esterified-pregelatinized starches that could be used as promising additives in low-energy formula foods.

Microstructured reactors offer fast chemical engineering transfer and precise microfluidic control, enabling the determination of reactions\' kinetic parameters. This review examines recent advancements in measuring microreaction kinetics. It explores kinetic modeling, reaction mechanisms, and intrinsic kinetic equations pertaining to two types of microreaction: esterification and transesterification reactions involving acids, bases, or biocatalysts. The utilization of a micro packed-bed reactor successfully achieves a harmonious combination of the micro-dispersion state and the reaction kinetic characteristics. Additionally, this review presents micro-process simulation software and explores the advanced integration of microreactors with spectroscopic analyses for reaction monitoring and data acquisition. Furthermore, it elaborates on the control principles of the micro platform. The superiority of online measurement, automation, and the digitalization of the microreaction process for kinetic measurements is highlighted, showcasing the vast prospects of artificial intelligence applications.