Water-in-Oil Pickering Emulsions Stabilized Solely by Water-Dispersible Phytosterol Particles.

Water-in-oil (W/O) Pickering emulsions were successfully synthesized by water-dispersible phytosterol (PS) particles formed through simple antisolvent precipitation. The effects of the organic/aqueous ratio on the particle morphology, crystallinity, and contact angle were investigated. Sheet-like PS particles with reduced crystallinity were further used as W/O Pickering emulsion stabilizers. The properties of the formed W/O emulsions could be transformed by changing the oil type, water-phase fraction, or particle contents. Results showed that emulsions with 80% water fraction could be stabilized by 3% particles in the aqueous phase, where dodecane was used as the oil phase. W/O Pickering emulsions stabilized by PS particles showed temperature responsiveness. When dried, PS particles could be well dispersed either in the water or oil phase to stabilize W/O Pickering emulsions. Therefore, this kind of PS particles could not only enrich the family of food-grade Pickering stabilizers, especially the W/O type, but also provide a smart Pickering stabilizer to fabricate environmental-responsive emulsion products.

Metabolism of anthocyanins and consequent effects on the gut microbiota.

Anthocyanins are natural water-soluble polyphenols present in fruits and vegetables. Health-promoting effects attributed to anthocyanins are mainly associated with oxidative stress inhibition and gut microbiota modulation. Dietary anthocyanins undergo a complex metabolism after ingestion and interact with endogenous and microbial enzymes, leading to the production of a large number of circulating and excreted anthocyanin metabolites and catabolic products. To date, the bioavailability and health benefits of anthocyanins have been widely documented. Although there are several papers that illustrated the metabolism of anthocyanins, the effects of dietary anthocyanins on the modulation of the gut microbial ecology and on the growth of certain microbial species are still poorly understood. The present paper summarizes the recent data on the absorption of anthocyanins in the upper gastrointestine and the metabolism of anthocyanins by gut microbiota. The modulatory effects of anthocyanins from different sources on gut microbiota are also discussed.

Roxithromycin regulates intestinal microbiota and alters colonic epithelial gene expression.

The specialty of gastroenterology will be affected profoundly by the ability to modify the gastrointestinal microbiota through the use of antibiotics. This study investigated the in vivo effect of roxithromycin on gut bacteria and gene expression of colonic epithelial cells (CECs) using microbial 16S rDNA and colonic epithelial cell RNA sequencing, respectively. The results showed that roxithromycin distinctly lowered the microbial diversity in both the small intestine and cecum and altered the compositions of bacteria at both the phylum and genus levels, including the reduction of some bacteria beneficial to the hosts' health. Eight decreased and 8 increased genera in the small intestine and 17 decreased and 4 increased genera of bacteria in the cecum were most affected by roxithromycin consumption. This consumption further altered the CECs' expression of multiple genes. Thirty-one genes, which were significantly enriched in seven KEGG pathways and related to immune response, wound healing, and fibrosis, were significantly affected. Roxithromycin ingestion in healthy hosts, therefore, might lead to some undesirable consequences via affecting hosts' gut microbiota and CECs. Our work offers a more comprehensive understanding of the impact of consuming roxithromycin on human health.

Two new flavonoids from the bark of Allium chrysanthum.

The isolation and structure elucidation of two new flavonoids, chrysanthumones A and B from the extracts of Allium chrysanthum were reported. Seven known phenolic constituents were also isolated. Their structures were determined on the basis of NMR and MS techniques.

Changes in pectin characteristics during the ripening of jujube fruit.

BACKGROUND: Pectin is related to fruit maturation and loss of flesh firmness. In this research, changes in pectin characteristics, including pectin content, neutral sugar composition, molecular weight (Mw ) distribution and degree of methylesterification (DM), in six different growth stages (S1 to S6) of jujube fruit were assessed. RESULTS: The growth of jujube fruit corresponded to an increase in water-soluble pectin (WSP) and a decrease in sodium carbonate-soluble pectin (SSP). The chelate-soluble pectin (CSP) content reached a maximum level at S3 but decreased significantly from S3 to S4. Arabinose proved to be the principal branched neutral monosaccharide in pectin during growth and was lost from WSP, CSP and SSP in S4 to S6. The ratios of (arabinose + galactose)/rhamnose indicated that the branched chains of WSP, CSP and SSP degraded in S2, S3 and S4 respectively. SSP depolymerized from S2 and increased as jujube fruit ripened. By contrast, WSP depolymerized throughout ripening. The DM of pectins ranged from 45.38 to 92.21%. Among the obtained DMs, the lowest was observed in WSP from ripened jujube fruit (S6). CONCLUSION: The content, neutral sugar composition, DM and Mw distribution of pectins changed markedly as jujube fruit ripened. Jujube fruit could be a promising alternative source of pectins in terms of maturation degree. WSP from S6 and CSP from S1 or S2 could be used as gelling agents in low-sugar-containing products because of their low methoxyl pectin contents. WSP from S1 could also be applied as a thickener or emulsifier owing to its high Mw distribution. © 2017 Society of Chemical Industry.

p-Coumaric acid and its conjugates: dietary sources, pharmacokinetic properties and biological activities.

p-Coumaric acid (4-hydroxycinnamic acid) is a phenolic acid that has low toxicity in mice (LD50 = 2850 mg kg(-1) body weight), serves as a precursor of other phenolic compounds, and exists either in free or conjugated form in plants. Conjugates of p-coumaric acid have been extensively studied in recent years due to their bioactivities. In this review, the occurrence, bioavailability and bioaccessibility of p-coumaric acid and its conjugates with mono-, oligo- and polysaccharides, alkyl alcohols, organic acids, amine and lignin are discussed. Their biological activities, including antioxidant, anti-cancer, antimicrobial, antivirus, anti-inflammatory, antiplatelet aggregation, anxiolytic, antipyretic, analgesic, and anti-arthritis activities, and their mitigatory effects against diabetes, obesity, hyperlipaemia and gout are compared. Cumulative evidence from multiple studies indicates that conjugation of p-coumaric acid greatly strengthens its biological activities; however, the high biological activity but low absorption of its conjugates remains a puzzle. © 2015 Society of Chemical Industry.

Feruloylated Oligosaccharides from Maize Bran Modulated the Gut Microbiota in Rats.

Corn bran is a byproduct produced from corn milling; it is rich in ferulic acid and hemicellulose. In this research, the effects of feruloylated oligosaccharides (FOs) from maize bran on the microbial diversity and profiles in rat feces were investigated through 16S rRNA sequencing. FOs significantly increased bacterial richness and diversity compared with the control and xylooligosaccharides (XOS) alone. In comparison with the control group and the group administrated with XOS, FOs orally administered at 300 mg/kg increased OTU in feces by 57.0 and 24.8 %, and Chao value by 93.4 and 37.6 %, respectively. FOs also influenced obesity- and diabetes-associated bacteria. Oral administration of FOs at 300 mg/kg decreased the ratio of Firmicutes to Bacteroidetes from 477.7:1 to 55.1:1; greatly increased the reads of bacteria that were previously found resistant against diabetes in rats, such as Actinobacteria, Bacteroides, and Lactobacillus; whereas decreased diabetes-prone bacteria, such as Clostridium and Firmicutes.

Lean rats gained more body weight than obese ones from a high-fibre diet.

There is controversy over previous findings that a high ratio of Firmicutes to Bacteriodetes helps obese animals harvest energy from the diet. To further investigate the relationship between microbial composition and energy harvest, microbial adaptation to diet and time should be considered. In this study, lean and obese rats were successfully induced with low-fat and high-fat diets. An 8-week high soyabean fibre (HSF)-containing diet was then fed to investigate the interaction between the diet and the rats' gut microbiota, as well as their influence on rats' growth. Rats' body weight (BW) was recorded weekly; their plasma lipids and their gut microbiota at week 11, 15 and 19 were analysed. After the consumption of the HSF diet, BW of lean rats increased significantly (P<0·05), but no significant alteration in BW was found in obese rats. The average content of plasma cholesterol was lowered and that of TAG was upgraded in both the groups when fed the HSF diet. There was no significant difference observed at each period between lean and obese rats. In the group of lean rats, the diversity of gut microbiota was elevated strongly (P<0·01), and bacteria from phylum Firmicutes and Bacteroidetes were both increased largely (P<0·01); however, the bacterial diversity and composition in obese rats were less altered after the HSF diet control. In conclusion, the increased Firmicutes and Bacteriodetes might relate to lean rats' higher BW gain; 'obese microbiota' could not help the hosts harvest more energy from the HSF diet.

A new dipeptide isolated from the bulb of garlic.

(R)-3-(allylthio)-2-((R)-3-(allylthio)-2-aminopropanamido)propanoic acid was isolated from the bulb of garlic, together with four known amino acids. Its structure was elucidated on the basis of 2D NMR and MS techniques. To the best of our knowledge, (R)-3-(allylthio)-2-((R)-3-(allylthio)-2-aminopropanamido)propanoic acid, which showed antibacterial activity against the Staphylococcus aureus antibiotic resistant strain, was the first example of dipeptide from garlic.

In vitro antioxidant activity of feruloyl arabinose isolated from maize bran by acid hydrolysis.

In this study feruloylated oligosaccharides (FOs) was released from maize bran by hydrochloric acid hydrolysis, and feruloyl arabinose (F-Ara) was obtained by D301 macroporous resin chromatography followed by polyamide resin purification from FOs. After structural identification, the antioxidant activity of F-Ara was evaluated in vitro by DPPH and superoxide radical scavenging activity assay, reducing power assay and chelating activity assay. The results show that F-Ara exhibited antioxidant activity in vitro when compared to standard antioxidants such as butylated hydroxyanisole, ferulic acid and L-ascorbic acid. The antioxidant activity depends on the concentration and increases with increasing dose of sample. The present study suggests that F-Ara possesses promising future for its strong reducing power, chelating activity and free radical-scavenging activity. Therefore, it can be a natural and efficient antioxidant used in food, medicine and cosmetic.

Glyoxal in Foods: Formation, Metabolism, Health Hazards, and Its Control Strategies.

Glyoxal is a highly reactive aldehyde widely present in common diet and environment and inevitably generated through various metabolic pathways in vivo. Glyoxal is easily produced in diets high in carbohydrates and fats via the Maillard reaction, carbohydrate autoxidation, and lipid peroxidation, etc. This leads to dietary intake being a major source of exogenous exposure. Exposure to glyoxal has been positively associated with a number of metabolic diseases, such as diabetes mellitus, atherosclerosis, and Alzheimer's disease. It has been demonstrated that polyphenols, probiotics, hydrocolloids, and amino acids can reduce the content of glyoxal in foods via different mechanisms, thus reducing the risk of exogenous exposure to glyoxal and alleviating carbonyl stresses in the human body. This review discussed the formation and metabolism of glyoxal, its health hazards, and the strategies to reduce such health hazards. Future investigation of glyoxal from different perspectives is also discussed.

Formation of Hesperetin-Methylglyoxal Adducts in Food and In Vivo, and Their Metabolism In Vivo and Potential Health Impacts.

Polyphenols with a typical meta-phenol structure have been intensively investigated for scavenging of methylglyoxal (MGO) to reduce harmful substances in food. However, less attention has been paid to the formation level of polyphenol-MGO adducts in foods and in vivo and their absorption, metabolism, and health impacts. In this study, hesperitin (HPT) was found to scavenge MGO by forming two adducts, namely, 8-(1-hydroxyacetone)-hesperetin (HPT-mono-MGO) and 6-(1-hydroxyacetone)-8-(1-hydroxyacetone)-hesperetin (HPT-di-MGO). These two adducts were detected (1.6-15.9 mg/kg in total) in cookies incorporated with 0.01%-0.5% HPT. HPT-di-MGO was the main adduct detected in rat plasma after HPT consumption. The adducts were absorbed 8-30 times faster than HPT, and they underwent glucuronidation and sulfation in vivo. HPT-mono-MGO would continue to react with endogenous MGO in vivo to produce HPT-di-MGO, which effectively reduced the cytotoxicity of HPT and HPT-mono-MGO. This study provided data on the safety of employing HPT as a dietary supplement to scavenge MGO in foods.

Esterification of black bean anthocyanins with unsaturated oleic acid, and application characteristics of the product.

Esterification of anthocyanins with saturated fatty acids have been widely investigated, while that with unsaturated fatty acids is little understood. In this study, crude extract (purity âˆ¼ 35 %) of cyanidin-3-O-glucoside (C3G) from black bean seed coat was utilized as reaction substrate, and enzymatically acylated with unsaturated fatty acid (oleic acid). Optimization of various reaction parameters finally resulted in the highest acylation rate of 54.3 %. HPLC-MS/MS and NMR analyses elucidated the structure of cyanidin-3-O-glucoside-oleic acid ester (C3G-OA) to be cyanidin-3-O-(6″-octadecene)-glucoside. Introduction of oleic acid into C3G improved the lipophilicity, antioxidant ability, and antibacterial activity. Further, the color and substance stability analyses showed that the susceptibility of C3G and C3G-OA to different thermal, peroxidative, and illuminant treatments were highly pH dependent, which suggested individual application guidelines. Moreover, C3G-OA showed lower toxicity to normal cell (QSG-7701) and better inhibitory effect on the proliferation of HepG2 cells than C3G, which indicated its potential anti-tumor bioactivity.

Effect of Sequential Inoculation of Tetragenococcus halophilus and Wickerhamomyces anomalus on the Flavour Formation of Early-Stage Moromi Fermented at a Lower Temperature.

Microbial inoculation in moromi fermentation has a great influence on the physicochemical and flavour properties of soy sauces. This work investigated the effect of inoculating Tetragenococcus halophilus and Wickerhamomyces anomalus on the flavour formation of early-stage moromi (30 days) fermented at a lower temperature (22 °C) by determining their physicochemical and aroma changes. The results showed that single yeast or LAB inoculation increased the production of amino nitrogen, lactic acid and acetic acid, as well as free amino acids and key flavour components. Particularly, the sequential inoculation of T. halophilus and W. anomalus produced more free amino acids and aromatic compounds, and there might be synergistic effects between these two strains. More characteristic soy sauce flavour compounds, such as benzaldehyde, HEMF, guaiacol and methyl maltol were detected in the sequentially inoculated moromi, and this sample showed higher scores in savoury, roasted and caramel intensities. These results confirmed that sequential inoculation of T. halophilus and W. anomalus could be a choice for the future production of moromi with good flavour and quality under a lower temperature.

Preparation and Characterization of a Novel Natural Quercetin Self-Stabilizing Pickering Emulsion.

In contrast to their well-known physiological properties, phytochemicals, such as flavonoids, have been less frequently examined for their physiochemical properties (e.g., surface activity). A natural quercetin self-stabilizing Pickering emulsion was fabricated and characterized in the present study. The antisolvent precipitation method was used to modify quercetin (in dihydrate form), and the obtained particles were characterized by light microscope, atom force microscope, XRD, and contact angle. The antisolvent treatment was found to reduce the particle size, crystallinity, and surface hydrophobicity of quercetin. We then examined the effects of the antisolvent ratio, particle concentration, and oil fraction on the properties of the quercetin particle-stabilized emulsions. In addition, increasing the antisolvent ratio (1:1~1:10) effectively improved the emulsification performance of the quercetin particles. The emulsion showed good storage stability, and the particle size of the emulsion decreased with the rising particle concentration and increased with the rising oil phase ratio. The findings indicate that natural quercetin treated with antisolvent method has a good ability to stabilize Pickering emulsion, and this emulsion may have good prospective application potential for the development of novel and functional emulsion foods.

Dietary phytochemical and metabolic disease prevention: Focus on plant proteins.

Plant-based functional foods have attracted increasing research interest to validate their use in preventing metabolic disease. Since it is increasingly recognized that inflammation, oxidative stress, and circadian rhythm play vital roles in various metabolic diseases, including diabetes, obesity and non-alcoholic liver disease, plant proteins, protein hydrolysates, and food extracts that intervene in these biological processes are promising dietary supplements to prevent metabolic diseases. Here, we reviewed the recent research on plant-based foods used for metabolic disease prevention and provided new perspectives regarding the current study gaps and future directions in this field.

Reduction in Five Harmful Substances in Fried Potato Chips by Pre-Soaking Treatment with Different Tea Extracts.

Thermally processed food always contains various types of harmful substances. Control of their levels in food is important for human health. This work used the extracts from green tea dust, old green tea, yellow tea, white tea, oolong tea, and black tea to simultaneously mitigate diverse harmful substances in fried potato chips. The six tea extracts (30 g/L) all showed considerable inhibitory effects on the formation of 5-hydroxymethylfurfural (reduced by 19.8%-53.2%), glyoxal (26.9%-36.6%), and methylglyoxal (16.1%-75.1%). Green tea and black tea extracts exhibited better inhibitory abilities than the other three teas and were further investigated for other harmful compounds by various concentration treatments. Finally, pre-soaking of fresh potato slices in 50 g/L extracts of green tea dust displayed, overall, the most promising inhibitory capacity of HMF (decreased by 73.3%), glyoxal (20.3%), methylglyoxal (69.7%), acrylamide (21.8%), and fluorescent AGEs (42.9%) in fried potato chips, while it exhibited the least impact on the color and texture. The high level of catechins in green tea dust may contribute most to its outstanding inhibitory effect, whereas the distinguished inhibitory effect of black tea extract was speculated to be attributable to the high levels of theaflavins and amino acids in the fully fermented tea. This study indicated that green tea dust, a predominant waste of the tea industry, had great potential to be exploited to improve food quality and safety.

Cytotoxicity of a Novel Compound Produced in Foods via the Reaction of Amino Acids with Acrolein along with Formaldehyde.

Acrolein (ACR) and formaldehyde (FA) are toxic aldehydes co-produced in foods. This work found that amino acids, the nucleophiles ubiquitously existing in foods, can react simultaneously with them. Six amino acids, including γ-aminobutyric acid (GABA), glycine, alanine, serine, threonine, and glutamine, can scavenge ACR and FA at 37, 85, and 160 °C. GABA had the highest scavenging capacity for ACR and FA, by 79 and 13% at 37 °C for 2 h, and 99 and 48% at 160 °C for 30 min, respectively. Moreover, a new type of compound with a basic structure of 5-formyl-3-methylene-3,6-dihydropyridin was identified in all reactions and formed by 1 molecule of FA and amino acid and 2 molecules of ACR. The content of this compound was higher than that of free ACR in typical thermally processed foods. Moreover, the compounds produced from different amino acids showed different cytotoxicity values. In gastric epithelial and human intestinal epithelial cell lines, the cytotoxicity values of serine-sourced and threonine-sourced products were lower than that of ACR but higher than that of FA, whereas others had less toxicity compared with the two aldehydes. Considering that the content of serine-sourced products was the highest in almost all tested foods, their safety needs to be evaluated.

Formation and Identification of a 5-(Hydroxymethyl)-2-Furfural-Zingerone Condensate and Its Cytotoxicity in Caco-2 Cells.

5-(Hydroxymethyl)-2-furfural (HMF), an active furfural, widely exists in various food products and has potential safety risks. It can be eliminated by occurring aldol condensation with α-unsubstituted ketones in the presence of catalysts. However, the elimination process between HMF and ketones from food is rarely studied. In this study, the adduct formation between HMF and zingerone (ZGR) catalyzed by proline was investigated. It revealed that the adduct formation led to 99.75% of HMF being trapped under the optimized reaction condition. Moreover, the in vitro digestion stability of HMF-ZGR adduct (HMZ) and its cytotoxicity against Caco-2 cells were evaluated. The results indicated that more than 75% of HMZ was remained after a three-stage simulated digestion. Following 24 and 48 h of incubation, HMZ exhibited cytotoxicity against Caco-2 cells with IC50 values of 41.47 ± 5.33 and 25.39 ± 3.12 mM, respectively, versus 35.39 ± 4.03 and 19.17 ± 2.10 mM by HMF.

Water-In-Oil Pickering Emulsions Stabilized by Microcrystalline Phytosterols in Oil: Fabrication Mechanism and Application as a Salt Release System.

Recently, Pickering emulsions stabilized by edible particles have attracted significant attention from the scientific community and food industry owing to their surfactant-free character. However, those edible particles are mostly used for stabilizing oil-in-water emulsions, whereas those for water-in-oil emulsions are very limited. In this article, stable water-in-oil Pickering emulsions were prepared through dispersing phytosterol particles in oil phase, and the effects of antisolvent treatment, the type of oil, particle concentration, and water fraction on the stability, type, and morphology of these emulsions were investigated. In addition, the release profile of salt as a model aqueous compound from these emulsions has also been studied. Results showed that due to its higher water content, the antisolvent pretreatment of phytosterol in the ethanol/water system facilitated the dispersion of dried phytosterol particles into oil phase as microcrystals. Water-in-oil Pickering emulsions with droplet sizes of 80-100 µm were fabricated at phytosterol concentrations of 1.5-3% w/v and water fractions of 0.2-0.6. The dissolved phytosterol molecules in oil phase could help in emulsion stabilization through interfacial crystallization during emulsification, evidenced by polar microscopic observations. Moreover, the salt release from phytosterol-stabilized Pickering emulsions showed a temperature-dependent profile which could have potential application in a controlled-release system. The current study provided important information for fabrication of stable water-in-oil emulsion using natural particles.