Abstract The eutectic point and drying curve of food multicomponent materials are the key to improve the efficiency of freeze-drying.The eutectic point, co-melting point, pre-freezing time, heating temperature and freeze-drying curve of Tremella fuciformis containing sucrose were investigated. The eutectic point and co-melting point temperature of materials were - 15.49 °C and - 8.35 °C respectively measured by differential scanning calorimetry (DSC). At the pre-freezing temperature of -25 °C for 3.5 h, the moisture of the sample was completely transformed into glassy ice. Different heating temperatures were set in sections during the drying process of multicomponent materials. The best heating temperature was 80°C for 3 hours, then 70 °C for 5 hours, then 60 °C for 12 hours, and finally 50 °C to constant dryness. Under the optimal operating conditions, Tremella fuciformis entered the desorption drying stage at the 8th hour, and the material could be dried to less than 5% moisture content at 25 h.

Abstract Hypsizygus marmoreus is a kind of edible fungus with high nutritional value. This investigation evaluated the influence of Hypsizygus marmoreus powder on the quality characteristics of noodles. The cooking time, cooked breaking ratio, cooking loss rate, color difference value, texture and sensory of noodles were measured. The addition of 4% to 20% mass fraction of mushroom powder had no significant effect on the cooking time and hardness of the noodles. The cooked breaking ratio of noodles increased from 0% to 13.27%, the cooking loss rate increased from 3.47% to 10.73%, the color difference value increased from 18.23 to 23.58, and the chewing hardness increased from 4569.66 g to 5888.68 g, with the mass fraction of mushroom powder increased from 0% to 20%. The sensory of noodles with 4% mushroom powder is the best. This study provides a certain theoretical basis for the further processing of Hypsizygus marmoreus.

Abstract To study the effect of okra aqueous extract on the intestinal flora of diabetic rats. Taking normal SD rats as CK group, diabetic rats induced by 40 mg/(kg•bw) streptozotocin (STZ) intraperitoneally as M group, normal and diabetic rats gavaged with 500 mg/(kg•bw) okra aqueous extract were CKO and MO groups,respectively. The bacterial flora of the cecum contents of rats was analyzed with 16S rRNA V3-V4 sequencing after 8 weeks of the experiment. Compared with CK, M increased Firmicutes 14.00% and decreased Proteobacteria 19.32% (P <0.01). Compared with M, MO down-regulated Lachnospiraceae 2.64% (such as Blautia, Anaerostipes), up-regulated Peptostreptococcaceae 1.20% in Firmicutes, and down-regulated Desulfovibrioceae 3.78% (such as Desulfovibrio) and up-regulated Burkholderia 5.24% (such as Parasutterella) in Proteobacteria. It is worth noting that MO up-regulated Christensenellaceae (LDA>4), which was negatively correlated with body mass index, inflammation, and metabolic syndrome. The okra aqueous extract reverses the changes of the intestinal flora of STZ-induced diabetic rats, which decreased Firmicutes and increased Proteobacteria by down-regulating Lachnospiraceae and Desulfovibrionaceae, up-regulating Burkholderiaceae, Christensenellaceae. The okra aqueous extract has the potential as a functional food with regulating intestinal microecology balance of diabetes.

Abstract Ergothioneine and selenium are biologically active substances that maintain human health. In order to increase the content of ergothioneine and selenium in the submerged fermentation products of Pleurotus eryngii, the non-nutritive culture conditions of submerged fermentation were investigated. When the concentration of sodium selenite was 3 μg/mL, the selenum conversion efficiency (94.78%) was the highest and the dry weight was the highest. The pH value of culture medium, shaking speed, culture temperature, inoculation amount and culture time affected the dry weight of fermentation, the content of ergothionein and selenium. The optimal culture conditions were optimized by single factor experiment as follows: pH 5.5 (natural), rotation speed 180 r/min, culture temperature 26 °C, inoculation amount 10%, and culture time 7 d. Under these conditions, the dry weight of Pleurotus eryngii fermentation product was 38.97 g/L, the ergothioneine content was 39.42 mg/L, and the bioconversion efficiency of selenium reached 84.63%.

Abstract The purpose of this investigation was to evaluate the effects of the addition of passion fruit peel flour (PFPF) from two different species to biscuits. Each PFPF was added to biscuit flour in different amounts (wheat flour replacement rate: 0%, 5%, 10%, and 15%). The colour and textural properties of the doughs and biscuits were evaluated. The physical characteristics, sensory characteristics and dietary fibre content of the biscuits were tested. Both types of PFPF show a higher fat absorption capacity (2.44 g/g (yellow) and 2.38 g/g (purple)). The results showed that the PFPF could significantly improve the texture of the prepared biscuits but showed an adverse effect on the colour. This study has shown that incorporation of PFPF (5%) can produce fibre-rich (TDF, 2.05% and 2.08%) biscuits with low water content (2.20% and 2.28%), excellent texture characteristics (Firmness, 13.18 N and 15.68 N) and good sensory quality.

Abstract Okra (AbelmoschusesculentusL.Moench) is widely planted in subtropical and tropical areas, with good palatability and a variety of biological activities. However, the hypoglycemic activity of okra aqueous extract and its mechanism were still unclear. In this paper, the hypoglycemic effect of okra aqueous extract on type 1 diabetic rats induced by streptozotocin (STZ) was investigated. The growth indicators, blood physiological and biochemical indicators (such as blood glucose, glucose tolerance, serum lipids, insulin, pyruvate kinase activity), histopathology of liver and pancreas were determined. Comparing with streptozotocin-induced diabetic rats group, the aqueous extract of okra treatment group exhibited decreasing blood glucose level (10.11%), glucose tolerance (12.00%), total triglyceride (41.59%), atherosclerosis index (49.20%), urine sugar (91.91%) and increasing insulin secretion (17.44%) and pyruvate kinase activity (57.41%). Okra aqueous extract significantly ameliorated STZ-induced steatosis of hepatocytes and islet cells. But, the feed intake, water intake, urine volume, and body weight of okra aqueous extract treated groups were not significantly different with those in normal rats groups or diabetic rats group, respectively. Therefore, the aqueous extract of okra was responsible for promoting insulin secretion, increasing pyruvate kinase activity and reducing blood glucose and lipid level.

Abstract Instant Tremella fuciformis is ready to eat after adding hot water and is a delicious edible mushroom food. However, the drying method affects the quality of product. The present work evaluated the effects of freeze drying (FD), microwave drying (MD), and hot air drying (HAD) on shrinkage ratio, rehydration ratio, microstructure, polysaccharide and free amino acids of instant Tremella fuciformis. These three drying methods significantly changed the color and reduced the total amount of amino acids of dried products. FD sample possessed a three-dimensional network with porous, loose and large voids, so it had a slighter shrinkage and a better rehydration effect compared with the MD and HAD one. The polysaccharide content, uronic acid content and soup’s viscosity of FD products were significantly higher than MD and HAD. Therefore, FD was more suitable for obtaining high-quality instant Tremella fuciformis products than MD and HAD.

Abstract To improve the stability of the phenolic extracts from plum fruit (Prunus salicina Lindl.), the microencapsulation conditions of spray drying were optimized by the response surface method. The Box-Behnken experimental results indicated the optimal conditions involved an inlet air temperature of 142.8 °C, a core material content of 23.7% and a feed solids content of 11.7%. The maximum microencapsulating efficiency was 87.7% at optimal conditions. Further, the physicochemical properties of the microcapsule powders were improved overall due to the addition of the coating agents. There were no statistically significant differences in phenolic content of the obtained microcapsules for the first 40 days of storage at 25 °C in dark condition (p > 0.05), and the retention rate of total phenol remained above 85% after 60 days. Microcapsules can be potentially developed as a source of natural pigment or functional food based on the advantages of rich phenolic compounds and red color.

Abstract Optimization of polyphenols extraction from plum (Prunus salicina Lindl.) was evaluated using response surface methodology. The Box-Behnken experimental results showed the optimal conditions involved an extraction temperature of 59 °C, a sonication time of 47 min, and an ethanol concentration of 61% respectively. The maximum extraction yield of total polyphenols was 44.74 mg gallic acid equivalents per gram of dried plum at optimal conditions. Polyphenol extracts exhibited stronger antioxidant activities than Vc by evaluating of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activity. Furthermore, polyphenol extracts (IC50 = 179 g/mL) showed obvious inhibitory effects on xanthine oxidase. These findings suggest that polyphenol extracts from P. salicina can be potentially used as natural antioxidant and xanthine oxidase inhibitory agents.