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With the continuous development of the livestock breeding industry, the amount of piggery wastewater discharged increases year by year, and the pressure of controlling environmental pollution continuously increases. A novel method using a co-culture of Chlorella pyrenoidosa and Rhodotorula glutinis in piggery wastewater was proposed in this study, which was aimed at treating piggery wastewater and producing useful products. The results showed that the optimal inoculum ratio of algae to yeast was 3 : 1 in the wastewater, which achieved the removal efficiencies of 58.53%, 36.07%, 33.20% and 56.25% for ammoniacal nitrogen (NH3-N), total nitrogen (TN), total protein (TP) and chemical oxygen demand (COD), respectively, after 6 d. The synergistic relationship of C. pyrenoidosa and R. glutinis was preliminarily validated using the oxygen/carbon dioxide exchange balance and scanning electron microscopy images. The co-cultivation system gained 59.8% (w/w) protein within 5 d which can be used as a feed additive, and produces aquatic animals with better growth and quality. Thus, the 1000 litre pilot scale bioreactor was used indoors and removed 82.65% of TN, 53.51% of TP, 93.48% of NH3-N and 85.44% of COD in 21 d which gave a better performance for TN (p < 0.05) than the bench scale results. This system improves the nutrition removal and protein production efficiencies, and is a promising method for piggery wastewater treatment and the pig breeding industry.

The Ala–Val–Thr–Phe (AVTF) peptide derived from edible Dendrobium aphyllum was co-incubated with Lactobacillus amylolyticus in a previous study. The aim of the present study was to further examine the antioxidative and protective effects of the AVTF peptides through the analysis of free-radical quenching in HepG2 cells subjected to 2,2-azobis(2-methylpropanimidamidine)dihydrochloride (AAPH)-induced oxidative stress and to determine the active sites within the peptide. Variations in intracellular malondialdehyde levels indicated that these peptides protect HepG2 cells by preventing ROS attack and lipid peroxidation. Antioxidant enzymes and Nrf2 were downregulated in AVTF-treated but not in AAPH-treated HepG2 cells, whereas the electrically sensitive Keap1 was not susceptible to free radical-induced damage after AVTF treatment. However, this did not result in the activation of the Nrf2/Keap1 signaling pathway, thus indicating that one potential mechanism by which AVTF maintains homeostasis in HepG2 cells is by directly scavenging free radicals. Furthermore, quantum chemical calculations and the assessment of electronic-related properties associated with antioxidant activity revealed that the active sites of AVTF included N9–H11, which was further confirmed by the assessment of ROS levels in methylated AVTF-treated cells. The results of this study provide valuable insights into the active site N9–H11 in the Ala residue of AVTF, which influences the antioxidant activity of the peptide.

Two kinds of flavone extracts were extracted and purified from Labisia pumila (LP). High-performance liquid chromatography (HPLC) analysis was used to determinate the flavones in the extracts, and catechin, glycitin, rutin, naringin, and myricetin were identified in the LP leaf extract (LPL-F) while genistin, naringin, and myricetin were found in the stem extract (LPS-F). Specific flavonol compounds mediated the satisfactory scavenging abilities. The flavone leaf extracts performed better than the stem extracts in chemical antioxidative activities but worse in cellular antioxidative capabilities. The chemical and cellular antioxidative activities were not obviously changed by gastrointestinal digestion but slightly changed at the last 2 hours of intestinal digestion because prolonged exposure to alkaline conditions could destroy the structure of flavonoids. Changes in MDA and GSH content, and enzyme activities of SOD and GSH-Px in human erythrocytes during GI digestion indicated the possible intracellular antioxidant-detoxifying mechanisms were through attenuating AAPH-induced oxidative stress by inhibiting ROS generation, in which stem extracts performed the better.

In vitro salivary and gastrointestinal (GI) digestion and fermentation of polysaccharides extracted from Dendrobium aphyllum were investigated in this study. Salivary amylase showed no influence on D. aphyllum polysaccharides (DAP). The molecular weight of DAP decreased dramatically during the first 0.5 h of gastric digestion, and then reduced steadily during the subsequent GI tract consumption. The content of reducing sugars increased steadily during GI digestion. Only released free mannose of DAP was detectable by gas chromatography-mass spectrometry analysis during the first 12 h of fermentation, which was contributed by fecal microbiota metabolism. In terms of the fermentation pattern, the pH dropped significantly due to the formation of six types of short-chain fatty acids (SCFAs). This study demonstrates that polysaccharides extracted from D. aphyllum can be digested by the GI tract and are physiologically active in the human large bowel by lowering the pH of the large intestinal environment and promoting the production of SCFAs.

Pomelo fruitlet is a side-product of pomelo, and this study aimed to extract the antioxidative flavonoid compounds from pomelo fruitlets with high efficiency through ultrasonic-associated microwave methods. Scanning electron microscopy analysis indicated that the spatial structure of the pomelo fruitlet powder was changed; microwaves and ultrasonic waves facilitated the formation of globular and curved surfaces, respectively. Ultrasonic-microwave synergistic pretreatment resulted in significantly higher yield. Each type of flavonoid compound was characterized using PR-LCMS analysis, and naringin with high nutritive value was detected in all groups. After purifying the flavone fractions with AB-8 macroporous resin, naringin, 2′′-O-acetyl-3′-O-methylrutin, and 5,7,8,3′-tetrahydroxy-3,4′-dimethoxy were identified, which could act as free radical scavengers to protect erythrocytes from AAPH-induced hemolysis. This study strongly improved the effects of ultrasonic-microwave synergetic methods on the high utilization of pomelo fruitlets, especially in terms of flavonoid extraction and bioavailability.

With the continuous development of the livestock breeding industry, the amount of piggery wastewater discharged increases year by year, and the pressure of controlling environmental pollution continuously increases. A novel method using a co-culture of