Physicochemical Characterization and Biological Properties of Polysaccharides from Alpiniae oxyphyllae Fructus.

Polysaccharides (AOPs) were extracted from Alpiniae oxyphyllae fructus using three distinct methods: hot water (AOP-HW), hydrochloric acid (AOP-AC), and NaOH/NaBH4 (AOP-AL). This study systematically investigated and compared the physicochemical properties, structural characteristics, antioxidant activities, and α-amylase inhibitory activities of the extracted polysaccharides. Among the three AOPs, AOP-AC exhibited the highest yield (13.76%) and neutral sugar content (80.57%), but had the lowest molecular weight (121.28 kDa). Conversely, AOP-HW had the lowest yield (4.54%) but the highest molecular weight (385.42 kDa). AOP-AL was predominantly composed of arabinose (28.42 mol%), galacturonic acid (17.61 mol%), and galactose (17.09 mol%), while glucose was the major sugar in both AOP-HW (52.31 mol%) and AOP-AC (94.77 mol%). Functionally, AOP-AL demonstrated superior scavenging activities against DPPH, hydroxyl, and ABTS radicals, whereas AOP-AC exhibited the strongest inhibitory effect on α-amylase. These findings indicate that the extraction solvent significantly influences the physicochemical and biological properties of AOPs, thus guiding the selection of appropriate extraction methods for specific applications. The results of this study have broad implications for industries seeking natural polysaccharides with antioxidant and enzymatic inhibitory properties.

Characterization, antioxidant and antitumor activities of phenolic compounds from Amomum villosum Lour.

Amomum villosum Lour. (A. villosum), known as Sharen in China, is widely used for culinary and medicinal purposes due to containing a diverse set of bioactive compounds. In this study, the optimum ethanol extraction process was optimized and the composition and biological activities (antioxidant and antitumor) of five different fractions (dichloromethane, petroleum ether, ethyl acetate, n-butanol and H2O) extracted from the ethanol extract of A. villosum were investigated. The results showed that the optimal extraction conditions were extraction temperature 80°C, extraction time 120 min, ethanol concentration 40% and solid-liquid ratio 1:25 g/mL. Moreover, 35 bioactive compounds were successfully identified by UPLC-ESI-QTOF-MS/MS from five factions for the first time, including 12 phenolic acids and derivatives, 2 organic acids, 12 flavonoids and derivatives, 2 oxylipins and 7 proanthocyanidins. Among them, ethyl acetate fraction (Fr-EtOAc) exhibited the highest content of total phenolic (374.01 mg GAE/g DW) and flavonoid (93.11 mg RE/g DW), where vanillic acid, catechin, epicatechin and protocatechuic acid were the predominant phenolic compounds that accounting for 81.65% of the quantified bioactive compounds. In addition, Fr-EtOAc demonstrated excellent total antioxidant activity (IC50 of DPPH and ABTS assays were 0.23, 0.08 mg/mL, respectively, and FRAP assay was 322.91 mg VCE/100 g DW) and antitumor activity (1,000 µg/mL, 79.04% inhibition rate). The results could provide guidance for the industrial production and application of A. villosum.

Macadamia oil-based oleogels as cocoa butter alternatives: Physical properties, oxidative stability, lipolysis, and application.

In this study, macadamia oil-based oleogels were prepared using monoglyceride stearate (MG) as a gelator with a low critical gelation concentration (3.0 wt%). The physical properties of the oleogels were evaluated by polarized light microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, texture and rheological analysis. And the lipid digestion and oxidative stability of the macadamia oil were determined by pH titration and accelerated oxidation test, respectively. The results showed that the hardness, oil binding capacity, and thermal stability of the oleogels increased with increasing MG concentration, which was attributed to the formation of a network of MG crystals held together by van der Waals interactions and hydrogen bonds. Rheological analysis indicated that all the oleogels exhibited a thermally reversible solid-to-liquid transition and viscoelastic behavior at ambient temperatures. Moreover, the formation of oleogels increased fatty acid release during in vitro lipid digestion and improved the oxidative stability of the macadamia oil. In addition, the potential application of these oleogels as replacements for saturated fats in foods was demonstrated by creating a chocolate product where the cocoa butter was replaced with macadamia oil-based oleogels with a high degree of unsaturation. These results can provide guidance for the preparation of macadamia oil-based oleogels, which may increase their application in foods.

The interaction and physicochemical properties of the starch-polyphenol complex: Polymeric proanthocyanidins and maize starch with different amylose/amylopectin ratios.

This study investigated the impact of polymeric proanthocyanidins (PPC) on the physicochemical characteristics of maize starch with varying amylose content, and their potential interaction mechanism. PPC with a lower content (1 %) reduced the viscoelasticity of the high amylose maize starch (HAM) system, inhibited amylose rearrangement, and enhanced its fluidity. However, excessive PPC restrained the interaction between PPC and amylose. In contrast to HAM, PPC improved the gelation ability of waxy maize starch (WAM) as PPC concentration was raised. PPC suppressed the recrystallization of starch during storage, and PPC had a superior inhibition influence on the retrogradation of WAM in comparison to HAM. This indicated that amylopectin was more likely to interact with PPC than amylose. Hydrogen bonds were the main driving force between PPC and starch chains, which was clarified by Fourier transform-infrared, nuclear magnetic resonance, X-ray diffraction, iodine bonding reaction, and dynamic light scattering data. Additionally, the mechanism of interaction between PPC and the two starch components may be similar, and variance in physicochemical attributes can be primarily credited to the percentage of amylose to amylopectin in starch.

A novel whole peanut butter refined by stirred media mill: The size, microstructure, rheology, nutrients, and flavor.

A novel whole peanut butter (PB) was developed using an emerging technology called stirred media mill (SMM). The impact of SMM on the size, microstructure, rheology, nutrient, and flavor of PB was investigated. The SMM treatment significantly decreased the particle size of PB, damaged cell structure, and released the oil body from cells. The apparent viscosity of PB decreased with the grinding process. Visual inspection revealed that the colloidal stability of PB was improved. The fatty acid composition was not affected by the grinding process. However, the tocopherol contents of the extracted oil slightly increased. Electronic nose and GC-MS analysis indicated that SMM could alter the flavor of PB after grinding for 45 min. Overall, SMM was a potential process technology to manufacture stable nut butter with smooth texture and delightful flavor profile.

Investigation of bovine ß-lactoglobulin-procyanidin complexes interactions and its utilization in O/W emulsion.

Procyanidins are bioactive polyphenols that have a strong affinity to proteins. Beta-lactoglobulin (BLG) is widely used as an emulsifier in the food and other industries. This study evaluated the interaction between BLG and A-type procyanidin dimer (PA2) using the spectroscopic, thermodynamic, and molecular simulation. PA2 decreased the transmissivity and quenched the intrinsic fluorescence of BLG, suggesting that the two molecules formed a complex. The binding of PA2 reduced the surface hydrophobicity and altered the conformation of BLG with increasing the random coil regions. Thermodynamic and isothermal titration calorimetry analyses suggested that the main driving force of PA2-BLG interaction was hydrophobic attraction. Molecular docking simulations were used to identify the main interaction sites and forces in the BLG-PA2 complexes, which again indicated that hydrophobic interactions dominated. In addition, the influence of PA2 on the ability of BLG to form and stabilize O/W emulsions was analyzed. Emulsions formulated using BLG-PA2 complexes contained relatively small droplets (D4,3 ≈ 0.7 µm) and high surface potentials (absolute value >50 mV). Compared to BLG alone, BLG-PA2 complexes improved the storage stability of the emulsions. This study provides valuable new insights into the formation, properties, and application of protein-polyphenol complexes as functional ingredients in foods.

Hypolipidemic effects of macadamia oil are related to AMPK activation and oxidative stress relief: In vitro and in vivo studies.

Macadamia oil is rich in monounsaturated fatty acids, especially a high level of palmitoleic acid, which may have beneficial health effects by lowering blood lipid levels. In our study, the hypolipidemic effects of macadamia oil and its potential mechanisms of action were investigated using a combination of in vitro and in vivo assays. The results showed that macadamia oil significantly reduced lipid accumulation, and improved triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels in oleic acid-induced high-fat HepG2 cells. The macadamia oil treatment also exhibited antioxidant effects, as seen by its ability to reduce reactive oxygen species and malondialdehyde (MDA) levels, and increase superoxide dismutase (SOD) activity. The effects of 1000 µg/mL of macadamia oil were comparable to that of 4.19 µg/mL simvastatin. The results of qRT-PCR and western blotting analyses indicated that macadamia oil effectively inhibited hyperlipidemia by reducing the expression levels of SREBP-1c, PPAR-γ, ACC and FAS and by enhancing the expression levels of HO-1, NRF2 and γ-GCS, via AMPK activation and oxidative stress relief, respectively. In addition, different doses of macadamia oil were found to significantly improve liver lipid accumulation, reduce serum and liver TC, TG, and LDL-C levels, increase HDL-C levels, increase antioxidant enzyme (SOD, GSH-Px, and T-AOC) activity, and decrease the MDA content of mice on a high-fat diet. These results indicated that macadamia oil had a hypolipidemic effect and provide insights that might facilitate the development of functional food and dietary supplements.

The Effects of Pectin Structure on Emulsifying, Rheological, and In Vitro Digestion Properties of Emulsion.

Pectin, a complex hydrocolloid, attracts extensive attention and application stemming from its good emulsification. However, the source of emulsification remains a conundrum. In this experiment, the structures of six kinds of commercial pectin, including LM 101 AS (101), LM 104 AS (104), 121 SLOW SET (121), YM 150 H (150), LM 13 CG (13CG), and ß-PECTIN (ß-P) were determined, and the effects of pectin structure on emulsion emulsification, rheology and in vitro digestibility were studied. The results showed that the ß-P pectin contained a higher content of protein, ferulic acid, and acetyl and had a lower interfacial tension; this pectin-stabilized emulsion exhibited a smaller droplet size and superior centrifugal and storage stability. The results showed that ß-P pectin had higher contents of protein, ferulic acid, and acetyl and lower interfacial tension than other pectins, and its stabilized emulsion exhibited smaller droplet size and superior centrifugation and storage stability. Furthermore, the emulsion formed by the pectin with high molecular weight and degree of methoxylation (DM) had a higher viscosity, which can inhibit the aggregation of emulsion droplets to some extent. However, the DM of pectin affected the charge and digestion behavior of pectin emulsion to a great extent. The smaller the DM, the more negative charge the emulsion carried, and the higher the release rate of free fatty acids. The results provided a basis for the rational selection and structural design of the pectin emulsifier.

Preparation of ethylenediamine-modified pectin/alginate/Fe3O4 microsphere and its efficient Pb2+ adsorption properties.

As a common macromolecular carbohydrate, pectin has a strong affinity for Pb2+. An ethylenediamine modified pectin (EP48) with 48 % of amidation was prepared and exhibited great removal efficiency towards Pb2+ in our previous study. However, the EP48 has drawbacks in adsorption including low mechanical strength and difficulty in separation. In this study, EP48 was compounded with sodium alginate (Alg) and Fe3O4 to synthesize EP48/Alg/Fe3O4 microsphere. The physicochemical properties and Pb2+ adsorption characteristics of microsphere were analyzed. It was found that the microsphere exhibited good thermal stability, mechanical strength, porous structure, as well as acid tolerance. The pseudo-second-order model well described the kinetics of adsorption process, indicating the chemical adsorption is dominant. The Langmuir model fitted the experimental data well, and the maximum adsorption capacity reached 175.19 mg/g. Adsorption-desorption experiments showed that the removal rate of the microsphere maintained over 98.9 % after 10 cycles. The X-ray photoelectron spectroscopy (XPS) analyses revealed that the potential adsorption mechanism included ion-exchange and chelation. The above results suggested its potential use for the removal of Pb2+ from wastewater.

Effects of Moderate Enzymatic Hydrolysis on Structure and Functional Properties of Pea Protein.

Pea protein (PP) was moderately hydrolyzed using four proteolytic enzymes including flavourzyme, neutrase, alcalase, and trypsin to investigate the influence of the degree of hydrolysis (DH) with 2%, 4%, 6%, and 8% on the structural and functional properties of PP. Enzymatic modification treatment distinctly boosted the solubility of PP. The solubility of PP treated by trypsin was increased from 10.23% to 58.14% at the 8% DH. The results of SDS-PAGE indicated the protease broke disulfide bonds, degraded protein into small molecular peptides, and transformed insoluble protein into soluble fractions with the increased DH. After enzymatic treatment, a bathochromic shift and increased intrinsic fluorescence were observed for PP. Furthermore, the total sulfhydryl group contents and surface hydrophobicity were reduced, suggesting that the unfolding of PP occurred. Meanwhile, the foaming and emulsification of PP were improved after enzymatic treatment, and the most remarkable effect was observed under 6% DH. Moreover, under the same DH, the influence on the structure and functional properties of PP from large to small are trypsin, alcalase, neutrase and flavourzyme. This result will facilitate the formulation and production of natural plant-protein-based products using PP.

Evaluation of Different Black Mulberry Fruits (Morus nigra L.) Based on Phenolic Compounds and Antioxidant Activity.

This study evaluated thirteen different black mulberry fruits (Morus nigra L.) grown in the Guangdong region in order to select the best cultivar for health benefits and commercial applications. The phenolic compounds were identified and quantified using UPLC-ESI-MS/MS. The antioxidant activity was evaluated by three in vitro methods. Significant differences among samples were found regarding total soluble solids (6.20-15.83 °Brix), titratable acidity (5.82-48.49 mg CA/g), total phenolic contents (10.82-27.29 mg GAE/g), total flavonoid contents (1.21-2.86 mg RE/g) and total anthocyanin contents (2.91-11.86 mg CE/g). Fifty-five different phenolic compounds were identified, of which fifteen were reported in mulberry for the first time, but only forty-six of them were quantitated. The DPPH radical scavenging activity, ABTS radical scavenging activity and ferric ion-reducing antioxidant power varied significantly among the samples. Overall, cultivars with better combinations of phenolic compounds and antioxidant activity were Qiong46 (M-2), Yuebanguo (M-4) and Heizhenzhu (M-10), which were recommended for commercial cultivation.

Characterization of a novel squalene-rich oil: Pachira macrocarpa seed oil.

Pachira macrocarpa is a woody oil crop with high economic and ornamental value. Although P. macrocarpa seeds are rich in oil, little information has been reported about its characterization. In this study, the fatty acids, minor components (tocopherols, squalene, phytosterols, and total phenols), antioxidant activity, cytotoxicity, thermal, and rheological behavior of the P. macrocarpa seed oil (PSO) were investigated for the first time. The results showed that the seeds contained 43.34% lipid, which was mainly composed of palmitic acid (49.96%), linoleic acid (31.22%), and oleic acid (13.48%). The contents of tocopherols, squalene, phytosterols, and total phenols in PSO were 42.01 mg/100 g, 96.78 mg/100 g, 119.67 mg/100 g, and 3.79 mg GAE/100 g, respectively. PSO showed relatively strong DPPH radical scavenging capacity (93.47 µmol TE/100 g) and high melting point (20.8°C). In addition, the oil exhibited Newtonian flow behavior and was not toxic to normal L929 cells at concentrations of 500-8000 µg/ml. As a whole, PSO may be considered as a valuable source for new multipurpose products for industrial utilization. PRACTICAL APPLICATION: Pachira macrocarpa is a woody oil crop and its seeds are rich in oil. Our study has investigated the physicochemical properties and chemical composition of the P. macrocarpa seed oil (PSO). The present study revealed PSO had potential as an edible oil, and it may be considered as a valuable source for new multipurpose products for food industrial utilization.

Development of Pectin-Based Aerogels with Several Excellent Properties for the Adsorption of Pb2.

Traditional aerogels lack specific functional groups for the adsorption of Pb2+, which results in a low adsorption capacity and limits the application scope. Novel porous pectin-based aerogels (PPEAs) were prepared by incorporating polyethylenimine (PEI) using ethylene glycol diglycidyl ether (EGDE) as a cross-linker for the removal of Pb2+ from water. The cross-linking mechanism, morphology, mechanical strength, thermal stability, adsorption properties, and mechanism of the aerogels were investigated. The aerogels possessed several desirable features, such as a large maximum Pb2+ adsorption capacity (373.7 mg/g, tested at pH 5.0), ultralight (as low as 63.4 mg/cm3), high mechanical strength (stress above 0.24 MPa at 50% strain), and easy recyclability. Meanwhile, the equilibrium adsorption data was well described by the Langmuir-Freundlich (Sips) model and the kinetic adsorption process was well fitted using the pseudo-second-order model. The donor groups, such as -NH2, and oxygen-containing functional groups were responsible for the Pb2+ adsorption, which was confirmed by the FTIR and XPS analysis. The excellent characteristics mean that PPEAs are highly effective adsorbents in the remediation of lead-containing wastewater.

Pectin/Activated Carbon-Based Porous Microsphere for Pb2+ Adsorption: Characterization and Adsorption Behaviour.

The development of effective heavy metal adsorbents has always been the goal of environmentalists. Pectin/activated carbon microspheres (P/ACs) were prepared through simple gelation without chemical crosslinking and utilized for adsorption of Pb2+. Scanning electron microscopy (SEM) revealed that the addition of activated carbon increased the porosity of the microsphere. Texture profile analysis showed good mechanical strength of P/ACs compared with original pectin microspheres. Kinetic studies found that the adsorption process followed a pseudo-second-order model, and the adsorption rate was controlled by film diffusion. Adsorption isotherms were described well by a Langmuir isotherm model, and the maximum adsorption capacity was estimated to be 279.33 mg/g. The P/ACs with the highest activated carbon (P/AC2:3) maintained a removal rate over 95.5% after 10 adsorption/desorption cycles. SEM-energy-dispersive X-ray spectrum and XPS analysis suggested a potential mechanism of adsorption are ion exchange between Pb2+ and Ca2+, electronic adsorption, formation of complexes, and physical adsorption of P/ACs. All the above results indicated the P/ACs may be a good candidate for the adsorption of Pb2+.

Effects of Three Types of Polymeric Proanthocyanidins on Physicochemical and In Vitro Digestive Properties of Potato Starch.

The effects of three types of polymeric proanthocyanidins (PPC) with different degrees of polymerization (DP), namely PPC1 (DP = 6.39 ± 0.13), PPC2 (DP = 8.21 ± 0.76), and PPC3 (DP = 9.92 ± 0.21), on the physicochemical characteristics and in vitro starch digestibility of potato starch were studied. PPC addition (5%, w/w) increased the gelatinization temperature and decreased some viscosity indices of potato starch, including the peak, trough, breakdown, and setback viscosities. Starch-PPC pastes showed reduced thixotropy and improved stability and gelling properties compared to starch paste. The three types of proanthocyanidins all showed evident inhibitory effects on the digestion and retrogradation of potato starch, including short-term and long-term retrogradation. Among the three, PPC with a lower DP had stronger effects on the starch short-term retrogradation and gelling performance, whereas larger PPC molecules exhibited a greater impact on starch recrystallization and digestive characteristics. The research consequences were conducive to explore the application of functional PPC in starch-based food processing.

Comparative Study of Chemical Compositions and Antioxidant Capacities of Oils Obtained from 15 Macadamia (Macadamia integrifolia) Cultivars in China.

The planting area of macadamia in China accounted for more than one third of the world's planted area. The lipid compositions, minor components, and antioxidant capacities of fifteen varieties of macadamia oil (MO) in China were comparatively investigated. All varieties of MO were rich in monounsaturated fatty acids, mainly including oleic acid (61.74-66.47%) and palmitoleic acid (13.22-17.63%). The main triacylglycerols of MO were first time reported, including 19.2-26.1% of triolein, 16.4-18.2% of 1-palmitoyl-2,3-dioleoyl-glycerol, and 11.9-13.7% of 1-palmitoleoyl-2-oleoyl-3-stearoyl-glycerol, etc. The polyphenol, α-tocotrienol and squalene content varied among the cultivars, while Fuji (791) contained the highest polyphenols and squalene content. Multiple linear regression analysis indicated the polyphenols and squalene content positively correlated with the antioxidant capacity. This study can provide a crucial directive for the breeding of macadamia and offer an insight into industrial application of MO in China.

Dynamic High-Pressure Microfluidization-Treated Pectin under Different Ethanol Concentrations.

We previously reported that dynamic high-pressure microfluidization (DHPM) can degrade pectin in aqueous solution. In this study, we further investigated the effect of DHPM on pectin in water-ethanol systems. In the absence of DHPM treatment, it was found that pectin exhibited increased average particle size and unchanged average molecular weight, but a decline in reducing-sugar-ends content with the increase of ethanol concentrations (0⁻10% v/v). These results indicated that the addition of ethanol induced aggregation of pectin. During DHPM treatment, pectin underwent disaggregation and degradation under all measured ethanol concentrations. Disaggregation was enhanced but degradation was weakened with the increase of ethanol concentration. FT-IR and UV spectra indicated that demethylation but no ß-elimination occurred in the water-ethanol system during DHPM. Finally, the mechanism of DHPM-induced disaggregation and degradation of pectin under a water-ethanol system was updated. This work may help us to find a suitable condition for reducing the degradation of pectin during the process of homogenization.

The effect of high speed shearing on disaggregation and degradation of pectin from creeping fig seeds.

The effect of high speed shearing (HSS) on disaggregation and degradation of pectin from creeping fig seeds was investigated. It was found that disaggregation and degradation occurred during the whole shearing process. When pectin solution was sheared at 24,000 rpm for less than 8h, degradation happened but disaggregation was dominant during this period. After 8h, degradation became obvious, however, a small amount of aggregates remained even after 24h treatment, indicating that HSS may not eliminate aggregates efficiently. The presence of aggregates is one of the most probable causes for the inaccurate determination of molecular weight of pectin. A new method was proposed for calculating more accurately the molecular weight based on the change of the reducing sugar content and the variation of molecular weight. Determination of unsaturated uronide and FT-IR spectra analysis indicated that neither ß-elimination nor demethoxylation occurred during the HSS, and no new functional group was formed during the HSS process.