Saikun Pan

Preparation of peach gum polysaccharides using hydrogen peroxide.

Most polysaccharides cannot dissolve in water but can be hydrolysed using hydrogen peroxide (H2O2) to yield a water-soluble product. This study presents a method of preparing water-soluble polysaccharides from peach gum by hydrolysis using H2O2. Extraction was monitored by the recovery rate. Factors affecting the hydrolysis of peach gum were investigated, and the optimum hydrolysis conditions were determined as follows: time, 8 h; temperature, 55°C; H2O2 concentration, 4% (v/v); and NaOH concentration, 2.0 M. The hydrolysates were filtered, neutralised with HCl, concentrated to ∼20% (w/v), precipitated with 5 volumes of ethanol, freeze-dried, and ground to yield a water soluble and white powder. The polysaccharide content of the product was 97.8%, and the yield was 83.6% (w/w).

Cellulase-assisted extraction and antioxidant activity of the polysaccharides from garlic

In the present study, the polysaccharides were prepared from garlic by using a cellulase-assisted extraction method and the antioxidant activity of garlic polysaccharides (GPs) was evaluated. To improve the yield of GPs, the influences of the several factors such as extraction time, temperature, pH, and cellulase amount on the extraction efficiency were studied. The optimal conditions for extraction of GPs were determined as follows: time, 80 min; temperature, 45 °C; pH, 5; cellulase amount, 8000 U/g. Under the optimised extraction conditions, the yield of GPS reached up to 35.34%. The GPs product exhibited strong antioxidant activity including hydroxyl radical scavenging activity, 2,2-diphenyl-β-picrylhydrazyl radical scavenging activity, and reducing power. The results suggest that the GPs could be used as potential antioxidants.

Influence of controlled pH on the activity of UDPG-pyrophosphorylase in Aureobasidium pullulans

UDPG-pyrophosphorylase is the key enzyme involved in pullulan biosynthesis and pullulan production by Aureobasidium pullulans. In this study, effect of controlled pH on fermentation time, pullulan production, biomass, and UDPG-pyrophosphorylase activity was investigated. Pullulan yield increased to reach a maximum within 4 days, and maximum UDPG-pyrophosphorylase activity was observed at day 3, while the biomass continued to increase until the end of the experimental period. The A. pullulans isolated from sea mud grew well at relatively low pH. UDPG-pyrophosphorylase activity was affected by the controlled pH and reached a maximum at pH 5.5. Results indicated that UDPG-pyrophosphorylase activity was highly correlated with controlled pH and pullulan biosynthesis rate.

Nutritional evaluation of protein from Clanis bilineata (Lepidoptera), an edible insect†

BACKGROUND This study was carried out to determine the nutritive quality of protein from Clanis bilineata (CB), an edible insect. RESULTS The protein content of dried CB was 685.3 g kg(-1) and its essential amino acid content was 528.4 g kg(-1), both of which are comparable to those of milk and eggs. Three groups of rats were fed diets containing either casein or CB protein (CBP) as protein source or a protein-free diet for 10 days. The nutritional parameters measured for the group fed the diet containing CBP showed a positive nitrogen balance of 1.37, a net protein retention of 2.9 and a true digestibility of 95.8%, comparable to those measured for the group fed the casein diet. CONCLUSION The results suggest that CBP may be a suitable alternative dietary protein source for humans.

Stimulating effects of polysaccharide from Angelica sinensis on the nonspecific immunity of white shrimps (Litopenaeus vannamei)

ABSTRACT Angelica sinensis polysaccharide (ASP) was prepared by hot water extraction. Then, high‐performance liquid chromatography and ion chromatography analyses were conducted, and the results indicated that ASP is a heteropolysaccharide, has a molecular mass of 82,000Da and consists of arabinose, galactose and glucose (molar ratio of 6:1:1). The effects of ASP on the nonspecific immunity of white shrimps (Litopenaeus vannamei) were investigated by feeding them with ASP‐containing diets (0.5, 1 and 1.5g/kg) during a 12‐week breeding experiment. Oral ASP administration significantly improved the survival rate, phenoloxidase activity, superoxide dismutase activity, glutathione peroxidase level, disease resistance against V. alginolyticus, total haemocyte count and number of hyaline cells, semigranular cells and granular cells (p<.05). ASP exhibits immunostimulatory effects on Pacific white shrimps (L. vannamei) and may thus be used as a diet supplement for them. HIGHLIGHTSThe shrimp body weight decreased when treated with ASP.Survival rate of shrimp increased when treated with ASP.Immune activity of shrimp increased when treated with ASP.Disease resistance of shrimp against V. alginolyticus when treated with ASP.

Myofibrillar protein denaturation in frozen and stored Clanis bilineata larvae as affected by pullulan

ABSTRACT Placing Clanis bilineata larvae in cold storage results in denaturation of their myofibrillar (MF) proteins, which alters their texture. In this study, the effect of pullulan on denaturation of MF proteins in C. bilineata larvae frozen at −18°C for 6 months was investigated. Different amounts of pullulan (2.5–7.5 g/100 g wet weight) were added to MF proteins. Alterations in MF protein properties, such as unfrozen water content, sulfhydryl content, calcium-adenylpyrophosphatase activity, and solubility, during frozen storage were evaluated. Pullulan enhanced these properties, suggesting that it is a promising cryoprotectant for C. bilineata larvae meat during frozen storage.