Structural Optimization of PA12/MVQ@POE-g-MAH Ternary Composite for Superior Toughness and Low-Temperature Resistance.

To enhance the low-temperature toughness and resistance of the engineering plastic polyamide PA12, this study introduces novel PA12/MVQ@POE-g-MAH ternary composites using a two-step process and dynamic curing. Analytical results indicate that incorporating MVQ@POE-g-MAH into the PA12 matrix markedly enhances its toughness and heat resistance. As the MVQ@POE-g-MAH content increases, the elongation at break of PA12 composites significantly expands from 52.83% to 204.69%, and the notch impact strength escalates from 8.69 to 74.34 kJ m-2. In addition, the brittleness temperature of PA12 decreases from -59.5 to -67.0 °C. Experimental findings confirm that POE-g-MAH is dispersed at the interface between MVQ and PA12, creating an encapsulated structure of MVQ@POE-g-MAH. This enhancement significantly broadens the potential applications of PA12 by improving its toughness, and resistance to both low and high temperatures, as well as impact endurance.

Paramyosin from field snail (Bellamya quadrata): Structural characteristics and its contribution to enhanced the gel properties of myofibrillar protein.

To assess the blending effect of field snails with grass carp muscle, the effects of paramyosin (PM) and actomyosin (AM) with different mixture ratios on the gel properties of the binary blend system were investigated in our work. The purified PM from field snail muscle was about 95 kDa on SDS-PAGE. Its main secondary structure was α-helix, which reached to 97.97 %. When the amount of PM increased in the binary blend system, their rheological indices and gel strength were improved. The water holding capacity (WHC) increased to 86.30 % at a mixture ratio of 2:8. However, the WHC and the area of immobile water (P22) dramatically decreased, and the area of free water (P23) increased when the mixture ratio exceeded 4:6. The low level of PM in binary blend system promoted the formation of a homogenous and dense gel network through non-covalent interactions as observed results of SEM and FTIR. When there were redundant PM molecules, the development of heterostructure via hydrophobic interaction of tail-tail contributed to the reduced gel properties of the binary blend system. These findings provided new insight into the binary blend system of PM and AM with different ratios to change the gel properties of myofibrillar protein.

Sodium alginate-sodium hyaluronate-hydrolyzed silk for microencapsulation and sustained release of kidney tea saponin: The regulation of human intestinal flora in vitro.

Kidney tea saponin (KTS) exhibits considerable efficacy in lowering glucose levels; however, it does not have widespread applications owing to its low intestinal utilization. Therefore, in the present study, we prepared sodium alginate (SA)/sodium hyaluronate (HA)/hydrolyzed silk (SF) gel beads for the effective encapsulation and targeted intestinal release of KTS. The gel beads exhibited an encapsulation rate of 90.67 % ± 0.27 % and a loading capacity of 3.11 ± 0.21 mg/mL; furthermore, the release rate of KTS was 95.46 % ± 0.02 % after 8 h of simulated digestion. Fourier transform infrared spectroscopy revealed that the hydroxyl in SA/HA/SF-KTS was shifted toward the strong peak; this was related to KTS encapsulation. Furthermore, scanning electron microscopy revealed that the gel bead space network facilitates KTS encapsulation. In addition, the ability of KTS and the gel beads to inhibit α-amylase (IC50 = 0.93 and 1.37 mg/mL, respectively) and α-glucosidase enzymes (IC50 = 1.17 and 0.93 mg/mL, respectively) was investigated. In vitro colonic fermentation experiments revealed that KTS increased the abundance of Firmicutes/Bacteroidetes and butyric acid-producing bacteria. The study showed that the developed gel-loading system plays a vital role in delivering bioactive substances, achieving slow release, and increasing the abundance and diversity of intestinal flora.

Mechanism study of the gel-forming ability of heat-induced gel from Peruvian hake (Merluccius gayi peruanus) surimi.

The commercial value of Peruvian hake (Merluccius gayi peruanus) meat is low because of its soft texture. This study investigated the major factor contributing to the gel-forming ability of Peruvian hake surimi by comparing the effects of endogenous protease activity and parasitic infection. Heat-induced gels could not be obtained at 50 °C-90 °C. Surimi with severe parasitic infection showed a stronger gel-forming ability. The endogenous protease activities were the main factor influencing the Peruvian hake meat proteolysis and contributed to the low gel-forming ability, rather than parasitic infection. Specifically, endogenous cysteine proteases played an essential role in protein degradation and low gel-forming ability. Moreover, endogenous transglutaminase was also shown to be involved in the gel-forming ability upon heating at 40 °C. These results suggested that Peruvian hake meat could be used as a raw material of frozen surimi for fish gel by inhibiting the activity of endogenous proteases.

Identification of high iron-chelating peptides with unusual antioxidant effect from sea cucumbers and the possible binding mode.

Iron deficiency anemia (IDA) is a common nutritional disease affecting 2 billion people. To develop a new iron-fortified food, we designed a novel type of iron-chelating peptide [Sea cucumbers peptides (SCP)-Fe] from sea cucumbers. SCP can chelate ferrous ions. The neutral protease hydrolysate have the highest iron chelating activity (117.17 ± 2.62 mg/g). Single factors including pH, material ratio, and molecular weight, had a significant effect on the iron chelating activity. The characterization of the SCP-Fe chelate revealed a loose and blocky structure with increased particle size. The amino acid composition, peptide identification and molecular docking indicated that Asp, Glu, Gly and Pro played an important role in binding to ferrous ions. After chelation, SCP-Fe chelate had dual nutrition effects of stronger radical scavenging ability and potential high-efficiency iron supplementation ability. These results might provide insights into the methods for developing functional foods such as iron-fortified seafood.

Release of bound polyphenols from wheat bran soluble dietary fiber during simulated gastrointestinal digestion and colonic fermentation in vitro.

Dietary fiber can act as a carrier of bound phenolics in the distal tracts of the gut, where potential microbial processing occurs, but specific mechanism is unclear. This study aimed to evaluate the release characteristic and activity of bound polyphenols from wheat bran soluble dietary fiber (SDF) during simulated gastrointestinal digestion and colonic fermentation in vitro. The result suggested that the bioaccessibility of bound polyphenols in colonic fermentation was 7.42 times that in gastrointestinal digestion stage. Gallic acid, p-hydroxybenzoic acid and vanillic acid were the most abundant polyphenol metabolites after the fermentation for 6 h. The released phenolics exhibited strong radical scavenging activity (DPPH, 99.22 ± 2.05 µmol TE/100 g DW; ABTS, 330.27 ± 3.56 µmol TE/100 g DW). Fecal fermentation of SDF significantly reduced the value of F/B and stimulated the growth of beneficial bacteria, such as Bacteroides, Akkermansia, and Faecalibacterium. Therefore, bound polyphenols may maintain gut health through their prebiotic activity.

The antidiabetic effects of Bifidobacterium longum subsp. longum BL21 through regulating gut microbiota structure in type 2 diabetic mice.

Bifidobacterium longum subsp. longum BL21 (BL21) possesses hypoglycemic activity, but its anti-diabetic mechanism has rarely been illustrated. In the present work, the effects of BL21 on type 2 diabetes mellitus (T2DM) were investigated in diabetic mice induced via a high-fat diet combined with streptozotocin (STZ). Our data indicated that BL21 at a dose of 109 CFU per day significantly lowered the levels of fasting blood glucose and alleviated insulin resistance in diabetic mice. Meanwhile, BL21 enhanced the anti-oxidative capacity, increased the hepatic glycogen content, and significantly decreased the gene expression levels of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) in the livers of diabetic mice. Endotoxemia-related inflammation and impaired intestinal barrier function in diabetic mice were also improved using BL21. More importantly, the disturbance of intestinal flora was regulated by BL21, including increased levels of the genera Akkermansia, Alloprevotella, Bacteroides, and Alistipes and decreased levels of Lachnospiraceae_NK4A136_group, Mucispirillum, and Odoribacter. Collectively, the amelioration of T2DM via BL21 supplementation might be partially attributed to regulation of the parameters related to glucose metabolism and the modulation of gut microbiota. Therefore, BL21 could be a potential functional food for ameliorating T2DM.

Effects of tyndallization temperature on the sterility and quality of kamaboko.

In this study, kamaboko gels were tyndallized at various temperatures and sterilization efficiency and impact on quality parameters were assessed. The microbiological, physical, and chemical properties of kamaboko gels were determined throughout the tyndallization process. Superior sterilization efficiency was achieved by tyndallization at a higher temperature; and the combination of heat-induced germination and thermal inactivation of spores was proposed as the main reason. The process had minimal effect on the color of gels. While tyndallized gels heated at 80 °C possessed superior physical properties, all gels showed impaired quality with the progress of heating cycles. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that the cause of alterations in quality differed depending on the processing temperature. This study suggests that the sterility of products could be improved by increasing the processing temperature, time or number of heating cycle.

The influence of processing sequence and frozen storage on the seasoned alaska pollack (Theragra chalcogramma) roe product quality.

The quality of seasoned products of Alaska pollack (Theragra chalcogramma) roe declined dramatically during frozen storage. This research investigated the effects of processing sequence and frozen storage period on seasoned Alaska pollack roe product quality. In addition, the relationship between mechanical properties and protein composition of ovary membrane and eggshell was discussed. The seasoned roe product made by the Seasoning-Frozen storage process showed higher mechanical property values, better surface color and more stable protein composition. The results clarified that this process allowed endogenous transglutaminase to act before it had been denatured and effectively prevented protein degradation during frozen storage. The retardation of protein degradation was probably attributed to cryoprotective effects from components in seasoning solution.

Correction: Bilberry anthocyanin improves the serum cholesterol in aging perimenopausal rats via the estrogen receptor signaling pathway.

Correction for 'Bilberry anthocyanin improves the serum cholesterol in aging perimenopausal rats via the estrogen receptor signaling pathway' by Na Li et al., Food Funct., 2019, 10, 3430-3438, DOI.

Rearrangement Strategy for the Preparation of Polymers With π-Conjugated Structures.

π-Conjugated polymers are usually prepared by polymerization only. In this perspective article, typical synthesis methods of conjugated polymers are briefly summarized, and a novel strategy for preparing conjugated polymers by rearrangement is proposed. During the metalation process, many conjugated structures were generated in polybutadiene by double bond migration. The effects of reaction time, temperature, and catalyst dosage on the product structure were investigated. Moreover, the structure of the products was confirmed by FTIR, 1H NMR, and 2D HSQC NMR spectra. Thus, a possible reaction mechanism was proposed, in which polybutadiene generates allylic carbanions in the presence of n-butyllithium, and then the double bonds migrate through the carbanions rearrangement to generate many conjugated structures in the backbone chain. The method shows promise in facile and low-cost synthesis of conjugated polymers without the need for precious metal catalysts.

Metal-Ligand Coordination Induced Ionochromism for π-Conjugated Materials.

Recent studies indicated that the toxicity of heavy metal ions caused a series of environmental, food, and human health problems. Chemical ionochromic sensors are crucial for detecting these toxicity ions. Incorporating organic ligands into π-conjugated polymers made them receptors for metal ions, resulting in an ionochromism phenomenon, which is promising to develop chemosensors for metal ions. This review highlights the recent advances in π-conjugated polymers with ionochromism to metal ions, which may guide rational structural design and evaluation of chemosensors.

Lactobacillus rhamnosus LRa05 improves lipid accumulation in mice fed with a high fat diet via regulating the intestinal microbiota, reducing glucose content and promoting liver carbohydrate metabolism.

To elucidate the anti-obesity effect of Lactobacillus rhamnosus LRa05 through the analysis of gut microbiota and liver metabolomics, we investigated changes in gut microbiota and liver metabolomic phenotypes in mice by 16S ribosomal RNA gene sequencing and ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. C57BL/6J male mice were orally administered with LRa05 for 8 weeks. Body weight, serum lipid levels, and the lipid accumulation of liver cells and epididymal fat tissues in the mice fed with a high-fat diet were inhibited after treatment with LRa05 at 1 × 109 CFU per day per mouse. LRa05 also reshaped the gut microbiota, reduced the abundance of the pro-pathogen bacterial Streptococcus, suppressed blood and liver glucose content, and promoted liver carbohydrate and energy metabolism. Moreover, Intestinimonas and palmitoyl ethanolamide exhibited a positive correlation, whereas Enterorhabdus and vitamin B2 showed a negative correlation. Therefore, LRa05 can potentially be used as an anti-obesity probiotic in further interventions.

Capsanthin extract prevents obesity, reduces serum TMAO levels and modulates the gut microbiota composition in high-fat-diet induced obese C57BL/6J mice.

The present study investigated the anti-obesity effects and its mechanism of capsanthin (CAP) in high-fat diet-induced obese C57BL/6J mice. Compared with untreated mice on a high-fat diet for 12 weeks, CAP at 200 mg kg-1 reduced the body weight by 27.5%, significantly reversed glucose tolerance, effectively decreased the serum triglycerides, total cholesterol, low-density lipoprotein cholesterol, and trimethylamine N-oxide levels, markedly increased microbial diversity. Furthermore, 16S rRNA gene sequencing of the cecal microbiota suggested that CAP increased the abundance of Bacteroidetes, Bifidobacterium and Akkermansia, decreased the abundance of Ruminococcus and the ratio of Firmicutes/Bacteroidetes. Moreover, predicted functional domain analysis indicated that CAP increased the gene abundance of replication and repair, and decreased the gene abundance of membrane transports and carbohydrate metabolisms. Therefore, it seems CAP exhibit anti-obesity effect and might be used as a potential agent against obesity.

Bilberry anthocyanin improves the serum cholesterol in aging perimenopausal rats via the estrogen receptor signaling pathway.

With aging, there is an increasing risk for women to develop perimenopause syndrome, which is harmful to women's physical and mental health. The present study investigated the health benefits of bilberry anthocyanin (BA) on aging perimenopausal Sprague-Dawley rats. Rats that entered into perimenopause through natural aging were treated for 8 weeks with BA, and received either a low dose (LD, 35 mg per kg of bodyweight), medium dose (MD, 70 mg per kg of bodyweight), or high dose (HD, 140 mg per kg of bodyweight). The experimental results suggested that all three dosages of BA, especially the high dose, significantly reduced the serum total cholesterol (TC), triglyceride (TG) and low density lipoprotein cholesterol (LDL-C) levels. In addition, BA supplementation markedly reduced the serum malondialdehyde (MDA), effectively increased the activity of hepatic total superoxide dismutase (T-SOD), significantly raised the high density lipoprotein cholesterol (HDL-C), increased the number of estrogen receptors, and effectively up-regulated the expression levels of G protein-coupled receptor 30 (GPR30), protein kinase B (AKT), and extracellular regulated protein kinase 2 (ERK2). In summary, BA has a great effect on improving the serum cholesterol in natural aging perimenopausal rats via the estrogen receptor signaling pathway, and it may be used as a dietary supplement for perimenopause women to decrease the risk of cardiovascular disease.

Buildup of Multi-Ionic Supramolecular Network Facilitated by In-Situ Intercalated Organic Montmorillonite in 1,2-Polybutadiene.

The development of a sacrificial bond provided unique inspiration for the design of advanced elastomers with excellent mechanical properties, but it is still a huge challenge to construct a homogenous polar sacrificial network in a nonpolar elastomer. In this effort, we proposed a novel strategy to engineer a multi-ionic network into a covalently cross-linked 1,2-polybutadiene (1,2-PB) facilitated by in-situ intercalated organic montmorillonite (OMMT) without phase separation. XRD, SEM, and TEM analysis were carried out to characterize the microstructure of the resulting polymers. Crosslinking density, dielectric performance, and cyclic tensile tests were used to demonstrate the interaction of zinc methacrylate (ZDMA) and OMMT. The dynamic nature of ionic bonds allowed it to rupture and reform to dissipate energy efficiently. Stretching orientation brought parallelism between polymer chains and OMMT layers which was beneficial for the reconstruction of the ionic network, ultimately resulting in high strength and a low stress relaxation rate. Overall, our work presented the design of a uniform and strong sacrificial network in the nano-clay/elastomer nanocomposite with outstanding mechanical performances under both static and dynamic conditions.

Relationship among pH, generation of free amino acids, and Maillard browning of dried Japanese common squid Todarodes pacificus meat.

Relationship among pH, generation of free amino acids (FAAs), and Maillard browning was investigated in Japanese common squid during air drying at 40 °C to prevent its discoloration. In the surface color measurement, increase in the b* value which is an indicator for Maillard browning of the dried squid was mitigated at pH 4.0-6.0 and accelerated at pH 7.5-9.0. Adjusting the pH to 5.5 effectively suppressed increasing of the b* value (p < 0.05). Arginine (Arg) generation involved in the Maillard reaction, was inhibited in the dried squid at pH 5.5 (p < 0.05). Maillard reactivities between ribose and amino acids were lower at pH 4.0 than at pH 5.5 (p < 0.05). These results indicate that browning of the dried squid is significantly suppressed at pH 5.5. Moreover, suppression of Arg generation is more effective than weakening of Maillard reactivity between ribose and Arg, in mitigating Maillard browning of the dried squid at an acidic pH.

The effect of organic salts on the browning of dried squid products processed by air-drying.

To control discoloration of dried Japanese common squid (Todarodes pacificus) product, influence of 0-1% organic salts, including sodium gluconate (Na-gluconate), sodium citrate (Na-citrate), sodium phytate (Na-phytate), sodium benzoate (Na-benzoate) and sodium tartrate (Na-tartrate), on Maillard browning in the squid meat during air-drying was investigated. Changes in surface color of the dried squid were mitigated by the addition of organic salts. Organic salts also showed inhibitory effects on autolysis and generation of free amino acids (FAAs), especially arginine, in both the dried squid meat and the model solution. Moreover, Maillard reaction degree of the dried squid was decreased by using organic salts. The addition of 1% Na-citrate or 1% Na-phytate well suppressed the browning of the dried squid (p < 0.05). The results indicated that organic salts having strong chelating ability, including Na-citrate and Na-phytate, can prevent the browning of the dried squid product by inhibiting the generation of FAAs.

The influence of proteases on the browning of dried squid products processed by air-drying.

To clarify why mantle meat from Japanese common squid (Todarodes pacificus) dried products discolor dramatically when processed by air-drying, the role of endogenous protease(s) on browning during the processing of dried squid products was studied. The involvement of endogenous protease(s) in the generation of Free Amino Acids (FAAs) participating in the Maillard reaction was characterized. The browning and myosin heavy chain degradation during air-drying were obviously mitigated by the addition of metalloprotease inhibitors, especially EGTA and 1,10-phenanthroline, followed by serine proteinase inhibitor, especially PMSF. The amount of total FAAs in dried products increased by only 0.17% with the addition of 1,10-phenanthroline and 5.0% with added EGTA. In autolysis models, protein autolysis was almost completely inhibited by 1,10-phenanthroline. The addition of, 1,10-phenanthroline inhibited the increase in total FAAs including arginine (Arg), followed by EGTA and PMSF. The results indicated that endogenous metalloproteases and serine proteases might influence the generation of FAAs including Arg, and contribute to product discoloration during air-drying.

Mechanism study of high browning degree of mantle muscle meat from Japanese common squid Todarodes pacificus during air-drying.

Mantle meat from the Japanese common squid (Todarodes pacificus) browns more than other squid meats during air-drying. The factors contributing to the browning of Japanese common squid, long-finned squid (Photololigo edulis) and bigfin reef squid (Sepioteuthis lessoniana) were studied in boiled and raw meat both before and after air-drying. Dried raw meat from the Japanese common squid browned more than dried boiled meat (b(∗) value, from 4.7 to 28.5). The results from SDS-PAGE showed significant degradation of myosin heavy chain (MHC) suggesting that protease activity in raw Japanese common squid meat was higher than in the other two species. The concentration of arginine (1932.0mg/100g) and ribose (28.8µmol/g) in Japanese common squid meat was higher than in the other two species. These results suggest that high protease activity and high concentrations of arginine and ribose increase the browning discoloration of Japanese common squid during air-drying.