Insights on the binding mechanism between specified aldehydes and flaxseed protein using multispectral image and molecular docking.

The binding and release behavior of flaxseed proteins to aldehydes is significant for the sensory properties of flaxseed foods. The key aldehydes of flaxseed were selected by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) method, and the interaction between flaxseed protein and flaxseed protein was investigated by multispectral, molecular docking, molecular dynamics simulation, and particle size techniques. The results showed that 2,4-decadienal presented a higher binding capability and a higher Stern-Volmer constant with flaxseed protein than pentanal, benzaldehyde, and decanal. Thermodynamic analysis revealed that hydrogen bonding and hydrophobic interactions were the main forces. Aldehydes contributed to a certain reduction in radius of gyration (Rg) value and α-helix content of flaxseed protein. In addition, the results of particle size showed that aldehydes caused the proteins to aggregate toward larger particles. This study could provide new insights into the interactions between flaxseed food and flavor.

Acidified glycerol as a one-step efficient green extraction and preservation strategy for anthocyanin from blueberry pomace: New insights into extraction and stability protection mechanism with molecular dynamic simulation.

In present work, green and efficient glycerol solvent system was coupled with pulse-probe ultrasonication for one-step extraction and preservation of anthocyanin from blueberry pomace. Under optimal conditions (40 min, 174 W, 18.6 mL/g, 20% of glycerol fraction), extraction yield was 23.07 ± 0.09 mg C3GE/g DW. The extracted anthocyanins were characterized by UPLC-Triple-TOF/MS and 10 anthocyanins compounds were tentatively identified. Stability of anthocyanins influenced by solvents were evaluated in varying temperature, pH and light exposure conditions, demonstrating higher stability of anthocyanins in glycerol solvent system than methanol one. Furthermore, mechanism of high efficiency extraction and stability of anthocyanin using glycerol were investigated by quantum chemical calculation with molecular dynamic simulation. Larger solvent accessible surface area (127.16 nm2), hydrogen bonds number (228.16) and hydrogen bonds lifetime (4.35 ps), and lower intermolecular interaction energy (-1080.48 kJ/mol) between anthocyanin and glycerol were responsible for better extraction and preservation of anthocyanins using glycerol system.

Biosynthesis and the Roles of Plant Sterols in Development and Stress Responses.

Plant sterols are important components of the cell membrane and lipid rafts, which play a crucial role in various physiological and biochemical processes during development and stress resistance in plants. In recent years, many studies in higher plants have been reported in the biosynthesis pathway of plant sterols, whereas the knowledge about the regulation and accumulation of sterols is not well understood. In this review, we summarize and discuss the recent findings in the field of plant sterols, including their biosynthesis, regulation, functions, as well as the mechanism involved in abiotic stress responses. These studies provide better knowledge on the synthesis and regulation of sterols, and the review also aimed to provide new insights for the global role of sterols, which is liable to benefit future research on the development and abiotic stress tolerance in plant.

Integrated natural deep eutectic solvent and pulse-ultrasonication for efficient extraction of crocins from gardenia fruits (Gardenia jasminoides Ellis) and its bioactivities.

This study proposed natural deep eutectic solvent (NADES) based pulse-ultrasonication-assisted extraction (P-UAE) for green recovery of crocins from gardenia fruits (Gardenia jasminoides Ellis). Choline chloride-1,2-propylene glycol (ChCl-PG, 1:2.5, mol/mol) with 35 % (v/v) water content was tailor-made to obtain the highest extraction efficiency with high surface tension, polarity, conductivity, pH, and low viscosity, density for affinity-based extraction of crocins. The optimized P-UAE conditions (extraction time 120 s, ultrasonic power 400 W, solvent-to-solid ratio 40 mL g-1, extraction temperature 35 ℃) led to the maximum yield of crocins (36.97 mg g-1 DW). The second-order kinetic model was fitted to the extraction process and the synergistic effect was verified by SEM and FTIR. The crocetin was identified as the main compound by UPLC-Triple-TOF/MS. The antiglycative effect and protective effect on DNA indicated the bioactive activities of crocins. Therefore, the ChCl-PG based P-UAE could serve as a green strategy to effectively extract crocins from gardenia fruits.

UPLC-Triple-TOF/MS characterization of phenolic constituents and the influence of natural deep eutectic solvents on extraction of Carya cathayensis Sarg. peels: Composition, extraction mechanism and in vitro biological activities.

Natural deep eutectic solvent (NADES) has received increasing interest as a green alternative to traditional organic solvents for efficient extraction of bioactive compounds from natural sources. In this study, phytochemicals in Carya cathayensis Sarg. peels extracted with Choline chloride-Malic acid (ChCl-MA) were identified using UPLC-Triple-TOF/MS. Effect of NADES on phenolic composition, antioxidant properties and inhibition of α-glucosidase and α-amylase were evaluated. Furthermore, extraction mechanism caused by different solvents were investigated by quantum chemical calculation combined with molecular dynamic simulation. A total of 29 phytochemicals were identified, and catechin, procyanidin B1, 2,3-dihydroxybenzoic acid, pinocembrin, procyanidin B3, myricetrin were the most abundant compounds. The extract using ChCl-MA exhibited the highest phenolic compounds content, antioxidant capacity, and α-glucosidase and α-amylase inhibition activities. Larger solvent accessible surface area, more hydrogen bonds between ChCl-MA and extract, longer lifetime of the hydrogen bonds, and lower intermolecular interaction energy account for higher extraction efficiency of ChCl-MA.

Roasting treatments affect oil extraction rate, fatty acids, oxidative stability, antioxidant activity, and flavor of walnut oil.

Introduction: The quality of pressed walnut oil can be improved by moderate roasting treatment. Methods: This study compared physicochemical characteristics and antioxidant ability of walnut oils pressed from differently roasted pretreated walnuts, analyzed the correlation among these indicators by using Pearson correlation coefficient and correlation coefficient heatmap, and evaluated the volatile organic compounds (VOCs) of walnut oil under optimal pretreatment roasting conditions using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). Results: Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were able to remarkably distinguish walnut oil produced by different roasting processes. In addition, correlation analysis showed that there was a significant impact among indicators. There were 73 VOCs were identified in the optimum roasted treated walnut oil, consisting of 30 aldehydes, 13 alcohols, 11 ketones, 10 esters, 5 acids, 2 oxygen-containing heterocycles, 1 nitrogen-containing heterocycle and 1 other compound. GC-IMS results showed that aldehydes contributed significantly to the volatile flavor profile of walnut oil, especially (E)-2-heptenal, (E)-2-pentenal and hexenal. Discussion: The properties of walnut oil based on varying roasting pretreatment of walnut kernels were significantly differentiated. Roasting at 120°C for 20 min is a suitable pretreatment roasting condition for pressing walnut oil. Roasting at 120°C for 20 min is a suitable pretreatment roasting condition for pressing walnut oil.

Sonication-synergistic natural deep eutectic solvent as a green and efficient approach for extraction of phenolic compounds from peels of Carya cathayensis Sarg.

An excellent high-efficiency natural deep eutectic solvent (NADES, ChCl-MA) was screened out and integrated with pulse-ultrasonication technique for extracting phenolic compounds from Carya cathayensis Sarg. peels (CCSPs). Single factor experiment combined with response surface methodology (RSM) using Box-Behnken design (BBD) were employed to investigate significant factors and optimize their influence on extraction of phenolic compounds. Significant synergistic effect triggered by ChCl-MA based pulse-ultrasonication over other methods used alone were proved by comparative study concerning a variety of bioactive components and antioxidant activities. The second-order kinetic model was developed and validated (R2 > 0.99) to describe the extraction process and its mechanism; and second-order kinetic extraction rate constant (k), saturation concentration (Cs), and initial extraction rate (h) were calculated. FT-IR, DSC and SEM results further demonstrated synergistic effect and influence during extraction. Overall, this study provided a green and high-efficiency alternative for the recovery of various phenolics compounds from plant source by-products.

Green Extraction of Phenolic Compounds from Lotus Seedpod (Receptaculum Nelumbinis) Assisted by Ultrasound Coupled with Glycerol.

Lotus Receptaculum Nelumbinis has been sparking wide research interests due to its rich phenolic compounds. In the present work, ultrasonic-assisted extraction coupled with glycerol was employed to extract phenolic compounds from Receptaculum Nelumbinis and the process was optimized using a response surface methodology with Box-Behnken design (BBD). The optimal conditions for the total phenolic content (TPC) extract were obtained: glycerol concentration of 40%, an extraction temperature of 66 °C, ultrasonic time of 44 min, and the solvent-to-solid ratio of 55 mL/g. Under these optimum extraction conditions, the extraction yield of TPC was 92.84 ± 2.13 mg gallic acid equivalents (GAE) /g. Besides, the antioxidant activities demonstrated the ability of free radical scavenging by four different methods that included 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and reducing activity (RA) were 459.73 ± 7.07, 529.97 ± 7.30, 907.61 ± 20.28, and 983.66 ± 11.80 µmol TE/g, respectively. Six phenolic compounds were identified by ultra-high pressure liquid chromatography combined with triple-time-of-flight mass spectrophotometry (UPLC-Triple-TOF/MS) from the extracts. Meanwhile, Fourier transform infrared (FTIR) was conducted to identify the characteristic functional groups of the extracts and thus reflected the presence of polyphenols and flavonoids. Scanning electron microscopy (SEM) illustrated the microstructure difference of four treatments, which might explain the relationships between antioxidant activities and the structures of phenolic compounds.

Interaction and binding mechanism of cyanidin-3-O-glucoside to ovalbumin in varying pH conditions: A spectroscopic and molecular docking study.

Egg ovalbumin (OVA) as a prevalent dietary protein and has the potential to serve as a carrier for unstable bioactive compounds, however, understanding their interaction mechanism is the preliminary step. In this work, the interactions between cyanidin-3-O-glucoside (C3G) and OVA in both acidic and neutral pH environment were investigated by spectroscopic methods and molecular docking analysis. The results revealed that fluorescence quenching mechanism of OVA-C3G was predominantly static. The main acting forces were hydrogen bonds and van der Waals forces under varying pH conditions. However, the binding affinity of C3G to OVA was higher in neutral environment than that in acidic condition. The binding of C3G slightly increased the diameter of the complex, resulting in increase of α-helix, decrease of ß-turn, random coil, and total main secondary structure. Moreover, the thermostability of C3G was significantly improved after OVA addition, suggesting its promising application in functional foods.

Sono-physical and sono-chemical effects of ultrasound: Primary applications in extraction and freezing operations and influence on food components.

Ultrasound is an advanced non-thermal food-processing technology that has received increasing amounts of interest as an alternative to, or an adjuvant method for, conventional processing techniques. This review explores the sono-physical and sono-chemical effects of ultrasound on food processing as it reviews two typical food-processing applications that are predominantly driven by sono-physical effects, namely ultrasound-assisted extraction (UAE) and ultrasound-assisted freezing (UAF), and the components modifications to food matrices that can be triggered by sono-chemical effects. Efficiency enhancements and quality improvements in products (and extracts) using ultrasound are discussed in terms of mechanism and principles for a range of food-matrix categories, while efforts to improve existing ultrasound-assist patterns was also seen. Furthermore, the progress of experimental ultrasonic equipments for UAE and UAF as food-processing technologies, the core of the development in food-processing techniques is considered. Moreover, sono-chemical reactions that are usually overlooked, such as degradation, oxidation and other particular chemical modifications that occur in common food components under specific conditions, and the influence on bioactivity, which was also affected by food processing to varying degrees, are also summarised. Further trends as well as some challenges for, and limitations of, ultrasound technology for food processing, with UAE and UAF used as examples herein, are also taken into consideration and possible future recommendations were made.

Effect of ultrasound on the production of xanthylium cation pigments in a model wine.

As a potential novel technique in the wine-making industry, ultrasound has received considerable attention. In this paper, a model wine system was constructed to investigate the effect of ultrasonic irradiation on the formation of xanthylium cation pigment derived from the (+)-catechin and the glyoxylic acid, an oxidation product of tartaric acid, so as to explore the changing mechanism of the wine color mediated by ultrasound. The results indicate that the long-term ultrasonic treatment can enhance the formation of the xanthylium cation pigment in the model wine, which is attributed to free radicals triggered by ultrasound, meanwhile, iron ions and oxygen can influence the ultrasonic effect. All these results suggest that ultrasound is promising to be employed in regulating the formation of the yellow pigment during wine aging thus modifying the wine organoleptic characteristic.

Effect of ultrasound on the interaction between (-)-epicatechin gallate and bovine serum albumin in a model wine.

Ultrasound is considered as a potential novel technique for improving the quality of some wines. In this paper, a model wine firstly was constructed with the standards of (-)-epicatechin gallate (ECG) and bovine serum albumin (BSA) as target compounds. Then, the experiments were conducted to investigate the effect of ultrasonic irradiation on the binding properties between ECG and BSA including quenching mechanism, binding parameters, binding forces, energy transfer distance and conformational changes determined by spectral analysis. The results indicate that ultrasound definitely has some regular effects on the binding interaction of BSA and ECG, and can induced the conformation variation of BSA in the simulated wine, which may suggest that the ultrasound might be employed to modify the wine organoleptic property by regulating the interaction between phenolic compounds and proteins from the autolysis of yeasts, since they are similar to the standards of ECG and BSA, respectively.