Pectin grafted with resorcinol and 4-hexylresorcinol: Preparation, characterization and application in meat preservation.

To augment the functional attributes of pectin and expand its prospective utilization in food preservation, this research explored the enzymatic grafting of resorcinol and 4-hexylresorcinol onto pectin. Structural analysis verified the successful grafting of both resorcinol and 4-hexylresorcinol to pectin via esterification, with the 1-OH of resorcinol and 4-hexylresorcinol and the carboxyl group of pectin functioning as grafting sites. The grafting ratios of resorcinol-modified pectin (Re-Pe) and 4-hexylresorcinol-modified pectin (He-Pe) were 17.84 % and 10.98 %, respectively. This grafting modification notably enhanced the antioxidative and antibacterial properties of pectin. Specifically, DPPH clearance and the inhibition ratio in the ß-carotene bleaching assay increased from 11.38 % and 20.13 % (native pectin, Na-Pe) to 41.15 % and 36.67 % (Re-Pe), and 74.72 % and 53.40 % (He-Pe). Moreover, the inhibition zone diameter against Escherichia coli and Staphylococcus aureus rose from 10.12 and 10.08 mm (Na-Pe) to 12.36 and 11.52 mm (Re-Pe), and 16.78 and 14.87 mm (He-Pe). Additionally, the application of native and modified pectin coatings effectively impeded pork spoilage, with the modified pectins demonstrating a more potent effect. Among the two modified pectins, He-Pe exhibited the most significant enhancement in pork shelf life.

Intelligent pH indicator composite film based on pectin/chitosan incorporated with black rice anthocyanins for meat freshness monitoring.

With the improvement of consumer awareness of food safety and the increasing concern about plastic pollution, the development of novel intelligent packaging film is imminent. This project aims to develop an environmentally friendly pH-sensitive intelligent food packaging film for meat freshness monitoring. In this study, anthocyanin-rich extract from black rice (AEBR) was added to composite film formed by the co-polymerisation of pectin and chitosan. AEBR showed strong antioxidant activity, and different colour responses to different conditions. The mechanical properties of the composite film remarkably improved when AEBR was incorporated into. Besides, the introduction of anthocyanins enables the colour of composite film to change from red to blue with the degree of meat spoilage increased which shows the indicative effect of composite films on meat putrification. Therefore, the AEBR-loaded pectin/chitosan film could be used as an indicator to monitor meat freshness in real-time.

Acylating blueberry anthocyanins with fatty acids: Improvement of their lipid solubility and antioxidant activities.

Aimed at exploring the impact of fatty acid side chains on the anthocyanins, n-valeric acid, n-decanoic acid and myristic acid were used to grafting onto the blueberry anthocyanins, and the acylating degree value of the of n-valeric acid acylated anthocyanins (Va-An), n-decanoic acid acylated anthocyanins (De-An) and myristic acid acylated anthocyanins (My-An) reached 6.43 %, 7.56% and 8.38 %, respectively. After acylation modification, the octanol-water partition coefficient of the anthocyanins increased from -0.20 (native anthocyanins, Na-An) to 0.65 (Va-An), 0.66 (De-An) and 0.72 (My-An), respectively, indicating the increasement of the lipid solubility. Besides, although the DPPH clearance of acylated anthocyanins was lower than that of native anthocyanins, the inhibition ratio of ß-carotene bleaching and malonaldehyde reduction effect of the acylated blueberry anthocyanins in Caenorhabditis elegans were both stronger than that of native anthocyanins, which might be caused by the improvement of lipid solubility of the anthocyanins.

Preparation of hydrophobic composite membranes based on carboxymethyl cellulose and modified pectin: Effects of grafting a long-chain saturated fatty acid.

In this study, docosanoic acid, a very long chain fatty acid, was used to modify pectin, and the products were incorporated with carboxylmethyl cellulose (CMC) to prepare a hydrophobic composite. Results of structural characterisation showed that docosanoic acid was grafted to pectin through the esterification reaction, and the highest grafting ratio was 7.89 %. After grafting with docosanoic acid, the emulsifying activity and stability of pectin were significantly enhanced from 1.23 × 10-2 and 9.27 % to 4.78 × 10-2 and 26.73 %. Moreover, when modified pectin was blended with CMC instead of native pectin, the hydrophobicity of the composite membranes increased significantly. In detail, the highest contact angle of the composite membrane incorporated with modified pectin was 97.6°, which was much higher than that with native pectin (68.9°). As the grafting ratio of pectin increased, the water vapor permeability of the composite membranes significantly increased, while the water absorption decreased. Furthermore, the mechanical properties and transparency of the composite membranes could be improved by grafting docosanoic acid into pectin. All the results indicated that incorporating docosanoic acid possibly helped improve the comprehensive properties of the composite membranes based on polysaccharides and expand their application in food packaging.

Catastrophe control of aphid populations model.

Considering the effect of the natural enemy on aphid populations, the corresponding model with delay is built. The model is analyzed using the qualitative theory of differential equations and catastrophe theory etc. For the outbreak phenomenon of aphid populations, the corresponding management model is proposed and the catastrophe controller is designed to keep the system in a virtuous cycle by means of the qualitative theory of impulsive differential equations. In the mean time, some simulations are carried to prove the results. The paper not only provides a new method for catastrophe control but also expands the application fields of catastrophe control.

Preparation of functionalized pectin through acylation with alkyl gallates: Experiments coupled with density functional theory.

The covalent grafting of alkyl gallates onto pectin using a lipase-catalyzed reaction in a tetrahydrofuran/aqueous medium process acylated pectin molecules with excellent antioxidant and antibacterial properties. The alkyl gallates including methyl, ethyl, and propyl gallates were enzymatically grafted onto pectin molecule, in order to study the effect of alkyl gallates on the functional modification of pectin. The grafting mechanism was analyzed by ultraviolet-visible spectrum (UV-Vis), Fourier transform infrared spectrum (FTIR), proton nuclear magnetic resonance (1HNMR), and density functional theory (DFT). Results suggested that lipase grafted 4-OH of alkyl gallate onto pectin by catalyzing esterification in organic/aqueous solution, and the grafting rate was affected by the length of alkyl chain of the gallates molecule. In vitro experiments, the acylated pectins exhibited stronger antioxidant activity in the DPPH test and ß-carotene bleaching test and were found to have obvious antimicrobial performance against Escherichia coli and Staphylococcus aureus.

Pectin modified with phenolic acids: Evaluation of their emulsification properties, antioxidation activities, and antibacterial activities.

Three phenolic acids including p-hydroxybenzoic acid (PHBA), 3,4-dihydroxybenzoic acid, (DHBA), and gallic acid (GA) were grafted onto native pectin (Na-Pe) through enzymatic method. Ultraviolet-visible spectrometry, Fourier transform infrared spectroscopy, and 1H NMR analyses were used to explore the reaction mechanism. Results indicated that the p-hydroxyl of the phenolic acids reacted with the methoxycarbonyl of pectin through transesterification, and a covalent connection was formed. The phenolic acid contents of PHBA modified pectin (Ph-Pe), DHBA modified pectin (Dh-Pe), and GA modified pectin (Ga-Pe) were 20.18%, 18.87%, and 20.32%, respectively. After acylation with phenolic acids, the 1,1-diphenyl-2-picryl hydrazine clearance of pectin changed from 7.68% (Na-Pe) to 6.88% (Ph-Pe), 40.80% (Dh-Pe), and 90.30% (Ga-Pe), whereas its inhibition ratio of pectin increased from 3.11% (Na-Pe) to 35.02% (Ph-Pe), 66.36% (Dh-Pe), and 77.89% (Ga-Pe). Moreover, compared with Na-Pe, modified pectins exhibited better emulsification properties and stronger antibacterial activities against both Escherichia coli and Staphylococcus aureus.

Increased retention of available nitrogen during thermal drying of solids of digested sewage sludge and manure by acid and zeolite addition.

Thermal drying is an increasingly common post-treatment for digestate-solids, but prone to N losses via ammonia (NH3) volatilization. Acidification with strong acids prior to drying may retain ammonium (NH4+) in the solids. Natural zeolites can provide adsorption sites for exchangeable cations as ammonium and porosity for free ammonia, which has the potential to contribute to higher N retention in the dried solids. The present study investigated whether the zeolite addition increases NH4+-N retention during thermal drying of two digestate solids (manure based, MDS; sewage sludge based, SDS), and whether any synergistic effects of combining acidification with sulfuric acid and the addition of zeolite exist. Operating conditions included four pH levels (non-acidified control, adjusted to 8.0, 7.5, 6.5 with concentrated sulfuric acid), four zeolite addition rates (0%, 1%, 5% and 10%), fixed drying temperature (130 °C) and fixed air ventilation rate (headspace exchange rate of 286 times hour-1). Zeolite addition significantly increased NH4+-N retention from 18.0% of initial NH4+-N in the non-acidified control up to a maximum of 57.4% for MDS, and from 76.6% to 94.5% for SDS. No positive synergistic effect between acidification and zeolite addition was observed, with acidification being the dominant. Nevertheless, zeolite has the potential to be a safe and easy-to-handle alternative to concentrated sulfuric acid.

Methane emissions responding to Azolla inoculation combined with midseason aeration and N fertilization in a double-rice cropping system.

Methane (CH4) is an important greenhouse gas (GHG), and paddy fields are major sources of CH4 emissions. This pot experiment was conducted to investigate the integrated effects of Azolla inoculation combined with water management and N fertilization on CH4 emissions in a double-rice cropping system of Southern China. Results indicated that midseason aeration reduced total CH4 emissions by 46.9%, 38.6%, and 42.4%, followed by N fertilization with 32.5%, 17.0%, and 29.5% and Azolla inoculation with 32.5%, 17.0%, and 29.5%, on average, during the early, late, and annual rice growing seasons, respectively. The CH4 flux peaks and total CH4 emissions observed in the late rice growing season were significantly higher than those in the early rice growing season. Additionally, CH4 fluxes correlated negatively to soil redox potential (Eh) and dissolved oxygen (DO) concentration. Azolla inoculation and N fertilization greatly increased the rice grain yields, whereas midseason aeration had distinct effects on grain yields in both rice seasons. The highest annual rice grain yields of approximately 110 g pot-1 were obtained in the Azolla inoculation and N fertilization treatments. In terms of yield-scaled CH4 emission, Azolla inoculation combined with midseason aeration and N fertilization generated the lowest yield-scaled CH4 emissions both in the early and in the late rice growing seasons, as well as during the annual rice cycle. In contrast, the highest yield-scaled CH4 emission was obtained in the treatment employed continuous flooding, without Azolla and no N application. Our results demonstrated that Azolla inoculation, midseason aeration, and N fertilization practices mitigated total CH4 emissions by 18.5-42.4% during the annual rice cycle. We recommend that the combination of Azolla inoculation, midseason aeration, and appropriate N fertilization can achieve lower CH4 emissions and yield-scaled CH4 emissions in the double-rice growing system.

A Highly Stable Separator from an Instantly Reformed Gel with Direct Post-Solidation for Long-Cycle High-Rate Lithium-Ion Batteries.

An efficient, scalable, and cost-effective approach was developed to synthesize a hierarchically constructed polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) separator from an instantly reformed solution. With partially dissolved PVDF-HFP as separator skeleton, the incorporation of warm PVDF-HFP solution in acetone led to a cross-linked structure before N-methyl-2-pyrrolidone (NMP) was added to solidify the hierarchical inner-bound structure of fresh PVDF-HFP. Owing to its hierarchical microporous structure, the separator exhibited remarkable wettability with a small contact angle of 18° and an electrolyte uptake of 114.81 %, leading to a high room-temperature ionic conductivity of 3.27×10-3  S cm-1 . The hierarchical structure provided short pathways for efficient ion transfer with more electrolyte trapped inside and small intervals between adjacent nanopores. The separator outperformed commercial separators, showing high rate capacities of 104.8 mAh g-1 at 5 C and 95 mAh g-1 at 10 C as well as unparalleled perfect capacity retention at 10 C after 1000 cycles.

Methane Emissions and Microbial Communities as Influenced by Dual Cropping of Azolla along with Early Rice.

Azolla caroliniana Willd. is widely used as a green manure accompanying rice, but its ecological importance remains unclear, except for its ability to fix nitrogen in association with cyanobacteria. To investigate the impacts of Azolla cultivation on methane emissions and environmental variables in paddy fields, we performed this study on the plain of Dongting Lake, China, in 2014. The results showed that the dual cropping of Azolla significantly suppressed the methane emissions from paddies, likely due to the increase in redox potential in the root region and dissolved oxygen concentration at the soil-water interface. Furthermore, the floodwater pH decreased in association with Azolla cultivation, which is also a factor significantly correlated with the decrease in methane emissions. An increase in methanotrophic bacteria population (pmoA gene copies) and a reduction in methanogenic archaea (16S rRNA gene copies) were observed in association with Azolla growth. During rice cultivation period, dual cropping of Azolla also intensified increasing trend of 1/Simpson of methanogens and significantly decreased species richness (Chao 1) and species diversity (1/Simpson, 1/D) of methanotrophs. These results clearly demonstrate the suppression of CH4 emissions by culturing Azolla and show the environmental and microbial responses in paddy soil under Azolla cultivation.

Hepatoprotective effects of polysaccharide isolated from Agaricus bisporus industrial wastewater against CCl4-induced hepatic injury in mice.

During the industrial production of canned mushroom (Agaricus bisporus), a large quantity of wastewater is produced. In this study, the wastewater generated during the canning of mushroom was analyzed. From this wastewater, four polysaccharide components (Abnp1001, Abnp1002, Abap1001, and Abap1002) with hepatic-protective activity were isolated by ultrafiltration, DEAE cellulose-52 chromatography and Sephadex G-200 size-exclusion chromatography. Results of ultraviolet spectra analysis and molecular weight determination showed that Abnp1001, Abnp1002, Abap1001 and Abap1002 were uniform with average molecular weights of 336, 12.8, 330 and 15.8kDa, respectively. The monosaccharide composition analysis using gas chromatography (GC) showed that the four fractions were heteropolysaccharides and mainly composed of glucose. Fourier transform-infrared (FT-IR) analysis showed that the isolated fractions were all composed of ß-glycoside linkages. Additionally, the potential hepatoprotective activities of these polysaccharides against CCl4-induced hepatic injury in mice were studied. Notably, Abnp1002 and Abap1002 could lower the alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations in serum in a dose dependent manner and reduce the hepatocellular degeneration and necrosis, as well as inflammatory infiltration. These results indicate that these two polysaccharides had protective effects on acute hepatic injury induced by CCl4 in mice and suggest that the polysaccharides extracted from A. bisporus industrial wastewater might have potential in therapeutics of acute hepatic injury.

Dietary chitosan improves hypercholesterolemia in rats fed high-fat diets.

The hypolipidemic mechanism of chitosan was investigated in male Sprague-Dawley rats. Animals were divided into 5 groups (n = 8): a normal fat control group, a high-fat control group (HF), a positive control group (CR), and 2 chitosan groups (CIS1 and CIS2). Chitosan was fed at the beginning (CIS1) and after 2 weeks (CIS2). A commercial diet with 5% (wt/wt) cellulose (HF), cholestyramine (CR), or chitosan (CIS1, CIS2) was fed for 6 weeks. Chitosan did not affect food intake but decreased body weight gain and significantly increased fecal fat and cholesterol excretion, reduced the lipid level in plasma and liver, increased liver hepatic and lipoprotein lipase activities compared with HF (P < .05), and tended to relieve the degenerated fatty liver tissue. No significant differences in all measurements were found between the CIS1 and CIS2 groups although the CIS1 rats exhibited lower lipid levels compared to those in the CIS2 group. The results suggest that chitosan reduced the absorption of dietary fat and cholesterol in vivo and could effectively improve hypercholesterolemia in rats.