Lipidomics analysis unveils the dynamic alterations of lipid degradation in rice bran during storage.

Recent explorations into rice bran oil (RBO) have highlighted its potential, owing to an advantageous fatty acid profile in the context of health and nutrition. Despite this, the susceptibility of rice bran lipids to oxidative degradation during storage remains a critical concern. This study focuses on the evolution of lipid degradation in RBO during storage, examining the increase in free fatty acids (FFAs), the formation of oxylipids, and the generation of volatile secondary oxidation products. Our findings reveal a substantial rise in FFA levels, from 109.55 to 354.06 mg/g, after 14 days of storage, highlighting significant lipid deterioration. Notably, key oxylipids, including 9,10-EpOME, 12,13(9,10)-DiHOME, and 13-oxoODE, were identified, with a demonstrated positive correlation between total oxylipids and free polyunsaturated fatty acids (PUFAs), specifically linoleic acid (LA) and α-linolenic acid (ALA). Furthermore, the study provides a detailed analysis of primary volatile secondary oxidation products. The insights gained from this study not only sheds light on the underlying mechanisms of lipid rancidity in rice bran but also offers significant implications for extending the shelf life and preserving the nutritional quality of RBO, aligning with the increasing global interest in this high-quality oil.

Lipidomics analysis of rice bran during storage unveils mechanisms behind dynamic changes in functional lipid molecular species.

Rice bran, recognized for its rich lipids and health-beneficial bioactive compounds, holds considerable promise in applications such as rice bran oil production. However, its susceptibility to lipid hydrolysis and oxidation during storage presents a significant challenge. In response, we conducted an in-depth metabolic profiling of rice bran over a storage period of 14 days. We focused on the identification of bioactive compounds and functional lipid species (25 acylglycerols and 53 phospholipids), closely tracking their dynamic changes over time. Our findings revealed significant reductions in these lipid molecular species, highlighting the impact of rancidity processes. Furthermore, we identified 19 characteristic lipid markers and elucidated that phospholipid and glycerolipid metabolism were key metabolic pathways involved. By shedding light on the mechanisms driving lipid degradation in stored rice bran, our study significantly advanced the understanding of lipid stability. These information provided valuable insights for countering rancidity and optimizing rice bran preservation strategies.

Enzymatic interfacial conversion of acylglycerols in Pickering emulsions stabilized by hydrogel microparticles.

HYPOTHESIS: A critical challenge in the enzymatic conversion of acylglycerols is the limited exposure of the enzyme dissolved in the aqueous solution to the hydrophobic substrate in the oil phase. Positioning the enzyme in a microenvironment with balanced hydrophobicity and hydrophilicity in Pickering emulsion will facilitate the acylglycerol-catalyzing reactions at the interface between the oil and liquid phases. EXPERIMENTS: In this work, to overcome the challenge of biphasic catalysis, we report a method to immobilize enzymes in polyethylene glycol (PEG)-based hydrogel microparticles (HMPs) at the interface between the oil and water phases in Pickering emulsion to promote the enzymatic conversion of acylglycerols. FINDINGS: 3 wt% of HMPs can stabilize the oil-in-water Pickering emulsion for at least 14 days and increase the viscosity of emulsions. Lipase-HMP conjugates showed significantly higher hydrolytic activity in Pickering emulsion; HMP-immobilized lipase SMG1 showed an activity about three times that of free lipase SMG1. Co-immobilization of a lipase and a fatty acid photodecarboxylase from Chlorella variabilis (CvFAP) in Pickering emulsion enables light-driven cascade conversion of triacylglycerols to hydrocarbons, transforming waste oil to renewable biofuels in a green and sustainable approach. HMPs stabilize the Pickering emulsion and promote interfacial biocatalysis in converting acylglycerols to renewable biofuels.

Streamlined enzymatic synthesis of human milk fat substitutes.

The positional distribution of palmitic acid (PA) in human milk fat substitutes (HMFSs) plays a pivotal role in mimicking the nutritional profile of human milk fat for nourishing non-breastfed infants. This study innovatively introduced a streamlined enzymatic process for preparing HMFSs rich in sn-2 PA using palm stearin, a PA-rich source without the necessity for positional distribution of PA. The initial step involved enhancing the sn-2 PA concentration through enzymatic interesterification using Lipase UM1, which exhibited superior catalytic efficiency than Novozym 435. This process increased the sn-2 PA level from 40.98 % to 64.51 %. Subsequently, acidolysis was employed to reduce PA levels by replacing PA at sn-1,3 positions using sn-1,3-regioselective lipases. The PA content decreased from 60.64 % to 26.73 %, simultaneously raising the relative sn-2 PA concentration to 71.57 %, meeting the benchmarks for HMFSs. This study establishes a robust conceptual framework for the prospective industrial synthesis of HMFSs.

Efficient Enzymatic Enrichment of High-purity Nervonic Acid from Malania oleifera Seed Oil.

Nervonic acid (NA) is a monounsaturated fatty acid vital for brain health and is of emerging importance in various industrial applications, including therapeutics, food, and cosmetics. Given the growing demands of the food and pharmaceutical industries, there's a pressing need for high-purity NA. Previously, NA constituents in plant seed oils were chemically transformed into nervonic acid ethyl ester (NAEE) to facilitate extraction from seed oils. In this study, we present an enzymatic approach to convert NA constituents in Malania oleifera seed oil to NAEE. Combined with the utilization of the semi-preparative chromatography, we achieved a remarkable purity of 97.52% NAEE. Compared to conventional chemical preparations characterized by multiple steps, prolonged processing times, and low yields and purities, our enzymatic method stands out as a more efficient and advantageous alternative. On top of that, this innovative approach is environmentally friendly and circumvents health and safety issues associated with chemical processes.

Crystal Structure of Fungal Nonspecific Phospholipase C Unveils a Distinct Catalytic Mechanism.

Nonspecific phospholipase C (NPC) plays a pivotal role in hydrolyzing phospholipids, releasing diacylglycerol─an essential second messenger. Extensive research has elucidated the structure and function of bacterial and plant NPCs, but our understanding of their fungal counterparts remains limited. Here, we present the first crystal structure of a fungal NPC derived from Rasamsonia emersonii (RePLC), unraveling its distinguishable features divergent from other known phospholipase C. Remarkably, the structure of RePLC contains solely the phosphoesterase domain without the crucial C-terminal domain (CTD) found in plant NPCs, although CTD is important for their activity. Through a comparative analysis of structural features among NPCs from diverse species combined with structure-based mutation analyses and bioinformatics methods, we propose a potential molecular mechanism that may universally underlie the catalysis of phospholipid hydrolysis in fungal NPCs. Furthermore, our study sheds light on the captivating evolutionary trajectory of enzymes across diverse species.

Physicochemical properties and feasibility of coconut oil-based diacylglycerol as an alternative fat for healthy non-dairy creamer.

Non-dairy creamers have been widely used for coffee whitening and texture improvement. To avoid the intake of trans fatty acids from partially hydrogenated oil, coconut oil-based diacylglycerol (CO-DAG) was applied in non-dairy creamer as core material. In this study, effects of DAG content (30, 50, 70, 90%) on the characteristics of CO-DAG were evaluated, including rheological and thermodynamic properties. The CO-DAG with a content of 50% exhibited a wide plastic range and contained mixture of ß and ß' polymorphic forms. Using CO-DAG (50%) as core material, the physicochemical properties of non-dairy creamer were characterized and compared with commercial products. The results indicated that CO-DAG-based non-dairy creamers showed similar encapsulation efficiency (92.74%) and thermal stability to commercial products. Furthermore, CO-DAG-based non-dairy creamer showed higher whiteness index (54.20) than commercial non-dairy creamers (50.22) when applied to black coffee. Overall, it is anticipated that CO-DAG-based non-dairy creamers have great potentials in coffee whitening.

Assessing the nutritional quality of lipid components in commercial meal replacement shakes using an in vitro digestion model.

This study aimed to investigate the nutritional value of five commercial meal-replacement shakes, and mainly focused on the lipid digestion fates and fat-soluble vitamin bioavailability. Four out of five samples exhibited a low lipolysis level (37.33-61.42%), aligning with the intended objectives of these products. Although the remaining sample rich in diacylglycerol (DAG) had a higher lipolysis level (80.83%), the inherent low-calorie nature of DAG might compensate for this drawback. The release level of individual fatty acid was largely determined by the glycerolipid composition. Moreover, the strong positive correlation between lipid hydrolyzed products amounts and the fat-soluble vitamin bioavailability was observed. Surprisingly, one out of five samples can provide enough vitamin A and vitamin E for consumers as a total replacement of one or two regular meals. Consequently, the meal-replacement shakes hold the potential to emerge as healthy products for this fast-paced era if the composition and structure were carefully designed and calculated.

Novel oxidation indicator films based on natural pigments and corn starch/carboxymethyl cellulose.

The existing oil oxidation detection methods are unsuitable for consumers to identify oil oxidation in a domestic setting. This study aims to develop indicator films detecting the degree of lipid oxidation with the naked eye. Purple sweet potato pigment (PSP) was chosen as a color indicator due to its response to hydrogen peroxide. The novel oxidation indicator films were prepared using corn starch, carboxymethyl cellulose (CMC), and varying concentrations of PSP. Fourier transform infrared spectroscopy spectra and scanning electron microscopy analysis confirmed the successful dispersion of PSP in the films. Thermal stability, light resistance, ultraviolet light resistance, mechanical resistance, and flexibility of films containing PSP were improved, enhancing the potential application in detecting oxidized substances. All the films exhibited noticeable color changes when exposed to different concentrations of hydrogen peroxide. These differences were more pronounced with higher levels of PSP. When these films were used to determine the degree of lipid oxidation, the ∆E value of the CS-PSP-0.25 % film showed a linear relationship (R2 = 0.929) with the peroxide value, unlike other films. Therefore, it is reliable to infer the peroxide value of edible oil by observing the color of the films, which helps customers avoid consuming expired oils.

Quality characteristics of peanut protein-based patties produced with pre-emulsified olive oil as a fat replacer: Influence of acylglycerol type.

The emulsion (O/W) may be used as a fat replacer to develop healthier meat analogs. The purpose of this work was to evaluate the effects of oil incorporation methods (direct oil addition and emulsion addition) and oil types [triacylglycerol (TAG) and diacylglycerol (DAG)] on the quality characteristics of peanut protein-based patties crosslinked by transglutaminase (TGase). The patties formulated with emulsions showed larger texture parameters (springiness, cohesiveness and gumminess), lower cooking loss and higher acceptability compared with directly adding oil. The rheological results confirmed that the presence of emulsions strengthened the gel structure in patties, which allowed the patties containing emulsions to stabilize free water. Whereas, TAG-based emulsion was more effective than DAG-based emulsion in improving quality of products, possibly because the competitive adsorption at oil-water interface of DAG reduced the crosslinking between the interfacial protein and adjacent protein molecules. This study revealed the relationship between the acylglycerol type in emulsion and the patty quality, providing a reference for the development of plant-based patties.

Influence of Proteins on Bioaccessibility of α-Tocopherol Encapsulation within High Diacylglycerol-Based Emulsions.

α-Tocopherol has been widely used in medicine, cosmetics, and food industry as a nutritional supplement and antioxidant. However, α-tocopherol showed low bioaccessibility, and there is a widespread α-tocopherol deficiency in society today. The preparation of oil-in-water emulsions with high safety and low-calorie property is necessary. The aim of this research was to investigate the effects of different protein emulsifiers (whey protein isolate (WPI), soy protein isolate (SPI), and sodium casein (SC)) on the properties of emulsions delivery system, and diacylglycerol (DAG) was picked as a low-accumulated lipid. The interfacial changes, microstructural alterations, and possible interactions of the protein-stabilized DAG emulsions were investigated during the in vitro digestion. The results show that different proteins affect the degree of digestibility and α-tocopherol bioaccessibility of the emulsions. Both WPI- and SPI-coated emulsions showed good digestibility and α-tocopherol bioaccessibility (77.64 ± 2.93%). This might be due to the strong hydrolysis resistance of WPI (ß-lactoglobulin) and the good emulsification ability of SPI. The SC-coated emulsion showed the lowest digestibility and α-tocopherol bioaccessibility, this might be due to the emulsification property of hydrolysis products of SC and the potential interaction with calcium ions. This study provides new possibilities for the application of DAG emulsions in delivery systems.

Effect of transglutaminase-catalyzed crosslinking behavior on the quality characteristics of plant-based burger patties: A comparative study with methylcellulose.

Transglutaminase (TGase) is gaining increasing recognition as a novel and healthier bio-binder for meat analogs. This work focused on the TGase-induced crosslinking behaviors, and then evaluated the difference in quality characteristics (Texture, water distribution, cooking properties, volatile flavor and protein digestibility) of peanut protein-based burger patties treated with TGase and traditional binder (methylcellulose, MC). TGase-catalyzed crosslinking, enabling amino acids to participate in the formation of covalent bonds rather than non-covalent bonds, and promoted the formation of protein aggregates and dense gel networks by changing the protein structure, ultimately improving the quality characteristics of burger patties. Compared with the TGase treatment, MC-treated burger patties showed a greater texture parameter, lower cooking loss, higher flavor retention but a lower degree of digestibility. The findings will contribute to a better understanding of the roles of TGase and traditional binders in plant-based meat analogs.

Co-encapsulation of probiotics with acylglycerols in gelatin-gum arabic complex coacervates: Stability evaluation under adverse conditions.

Co-encapsulation of acylglycerols and probiotics may improve the resistance of probiotics to adverse conditions. In this study, three probiotic microcapsule models were constructed using gelatin (GE)-gum arabic (GA) complex coacervate as wall material: microcapsules containing only probiotics (GE-GA), microcapsules containing triacylglycerol (TAG) oil and probiotics (GE-T-GA) and microcapsules containing diacylglycerol (DAG) oil and probiotics (GE-D-GA). The protective effects of three microcapsules on probiotic cells under environmental stresses (freeze-drying, heat treatment, simulated digestive fluid and storage) were evaluated. The results of cell membrane fatty acid composition and Fourier transform infrared (FTIR) spectroscopy revealed that GE-D-GA could improve the fluidity of cell membrane, maintain the stability of protein and nucleic acid structure, and decrease the damage of cell membrane. These characteristics supported the high freeze-dried survival rate (96.24 %) of GE-D-GA. Furthermore, regardless of thermotolerance or storage, GE-D-GA showed the best cell viability retention. More importantly, GE-D-GA provided the best protection for probiotics under simulated gastrointestinal conditions, as the presence of DAG reduced cell damage during freeze-drying and the degree of contact between probiotics and digestive fluids. Therefore, co-microencapsulation of DAG oil and probiotics is a promising strategy to resist adverse conditions.

Deep-fat Frying Using Soybean Oil-based Diacylglycerol-Palm Olein Oil Blends: Thermo-oxidative Stability, 3-MCPDE and Glycidyl Ester Formation.

Diacylglycerol (DAG) is commonly known as one of the precursors for the 3-monochloro-1,2-propanediol esters (3-MCPDE) and glycidyl esters (GE) formation. However, due to its health-promoting effects, its potential as alternative frying medium was examined. This study aimed to assess the frying performance of soybean oil-based diacylglycerol oil (DO) and its oil blends with palm olein (PO), in comparison with PO. Four different oil types (DO, PO, OB I (DO:PO, 1:1, w/w) and OB II (DO:PO, 1:2, w/w)) were used to fry potato chips for five consecutive days at 180℃. The formation of oxidation compounds, acylglycerol composition, 3-MCPDE and GE changes throughout the frying study were investigated. Both OB I and OB II exhibited lower oxidation compounds' formation rates than PO. Besides, significant (p < 0.05) reductions of 3-MCPDE and increments of GE levels were observed in all frying systems throughout the frying study. After 25 frying cycles, the 3-MCPDE levels in all frying oils were below 0.13 mg/kg, while the GE levels ranged from 1.51 mg/kg to 1.89 mg/kg. Despite the poorer oxidative stability of DO, its 3-MCPDE and GE levels were much lower compared to PO. In comparison to DO, the 3-MCPDE degradation and GE formation rates were enhanced and reduced, respectively with the blending of PO and DO. This study showed the potential of DO:PO oil blend in deep-fat frying application. With appropriate blending ratio of DO and PO, an alternative frying medium with enhanced nutritional value and oxidative stability could be developed.

Exploring the fates and molecular changes of different diacylglycerol-rich lipids during in vitro digestion.

This study aimed to support the pursuit of healthy oils and investigate the relationships between lipid compositions and digestion fates of diacylglycerol (DAG)-rich lipids using an in vitro digestion model. Soybean-, olive-, rapeseed-, camellia-, and linseed-based DAG-rich lipids (termed SD, OD, RD, CD, and LD, respectively) were selected. These lipids exhibited identical lipolysis degrees (92.20-94.36 %) and digestion rates (0.0403-0.0466 s-1). The lipid structure (DAG or triacylglycerol) was a more important factor affecting the lipolysis degree than other indices (glycerolipid composition and fatty acid composition). For RD, CD and LD with similar fatty acid compositions, the same fatty acid had different release levels, probably due to their different glycerolipid compositions (causing different distributions of the fatty acid in UU-DAG, USa-DAG and SaSa-DAG; U: unsaturated fatty acids, Sa: saturated fatty acids). This study provides insights into the digestion behaviors of different DAG-rich lipids and supports their food or pharmaceutical applications.

An ultra-rapid and eco-friendly method for determination of loganic acid and gentiopicroside from Gentianae Macrophyllae Radix by vortex-assisted matrix solid-phase dispersion extraction and LC-MS.

An ultra-rapid and eco-friendly method for the determination of loganic acid and gentiopicroside in Gentianae Macrophyllae Radix (GMR) was developed by vortex-assisted matrix solid-phase dispersion extraction (VAMSPD) and liquid chromatography with mass spectrometry (LC-MS). The optimized VAMSPD parameters are as follow: sample-dispersant (diatomaceous earth) ratio is 1:5, grinding for 0.5 min and whirling with 0.5 mL 15 % ethanol for 0.5 min. The LC separation is performed on a Poroshell 120 EC-C18 column (30 ×2.1 mm, 2.7 µm) and eluted by an eco-friendly mobile phase (14 % ethanol containing 0.1 % formic acid) at a flow rate of 0.5 mL min-1 in isocratic mode, and detected by mass spectrometry (MS). The developed method exhibits a good linearity for the analytes (r > 0.9990). The RSDs of precision and repeatability are less than 4.0 %, the recoveries for loganic acid and gentiopicroside are 106.5 % (RSD=3.6 %) and 95.7 % (RSD=8.0 %), respectively. The developed method was successfully applied in the analysis of loganic acid and gentiopicroside in GMR samples. The total analysis time is 2 min, including 1 min for sample extraction and 1 min for LC-MS analysis. In addition, the method only requires 0.3 mL of ethanol.

Soy lecithin increases the stability and lipolysis of encapsulated algal oil and probiotics complex coacervates.

BACKGROUND: Co-encapsulation of probiotics and omega-3 oil using complex coacervation is an effective method for enhancing the tolerance of probiotics under adverse conditions, whereas complex coacervation of omega-3 oil was found to have low lipid digestibility. In the present study, gelatin (GE, 30 g kg-1 ) and gum arabic (GA, 30 g kg-1 ) were used to encapsulate Lactobacillus plantarum WCFS1 and algal oil by complex coacervation to produce microcapsules containing probiotics (GE-P-GA) and co-microcapsules containing probiotics and algal oil (GE-P-O-GA), and soy lecithin (SL) was added to probiotics-algal oil complex coacervates [GE-P-O(SL)-GA] to enhance its stability and lipolysis. Then, we evaluated the viability of different microencapsulated probiotics exposed to freeze-drying and long-term storage, as well as the survival rate and release performance of encapsulated probiotics and algal oil during in vitro digestion. RESULTS: GE-P-O(SL)-GA had a smaller particle size (51.20 µm), as well as higher freeze-drying survival (90.06%) of probiotics and encapsulation efficiency of algal oil (75.74%). Moreover, GE-P-O(SL)-GA showed a higher algal oil release rate (79.54%), lipolysis degree (74.63%) and docosahexaenoic acid lipolysis efficiency (64.8%) in the in vitro digestion model. The viability of microencapsulated probiotics after simulated digestion and long-term storage at -18,4 and 25 °C was in the order: GE-P-O(SL)-GA > GE-P-O-GA > GE-P-GA. CONCLUSION: As a result of its amphiphilic properties, SL strongly affected the physicochemical properties of probiotics and algal oil complex coacervates, resulting in higher stability and more effective lipolysis. Thus, the GE-P-O(SL)-GA can more effectively deliver probiotics and docosahexaenoic acid to the intestine, which provides a reference for the preparation of high-viability and high-lipolysis probiotics-algal oil microcapsules. © 2022 Society of Chemical Industry.

Monoacylglycerol lipase from marine Geobacillus sp. showing lysophospholipase activity and its application in efficient soybean oil degumming.

Enzymatic degumming is an essential refining process to improve oil quality. In this study, a monoacylglycerol lipase GMGL was derived from marine Geobacillus sp., and was found that not only took monoacylglycerol (MAG) as substrate, but also had activity toward lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE) and glycerolphosphatidylcholine (GPC). Binding free energy showed LPC and LPE could bind with enzyme stably as MAG. It presented great potential in the field of enzymatic degumming. The phosphorus content in crude soybean oil decreased from 680.50 to 2.01 mg/kg and the yield of oil reached to 98.80 % after treating with phospholipase A1 (Lecitase Ultra) combined with lipase GMGL. An ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed to identify 21 differential phospholipids between crude soybean oil and enzymatic treatment. This work might shed some light on understanding the catalytic mechanism of monoacylglycerol lipase and provide an effective strategy for enzymatic degumming.