Abstract This study aims to develop a batter system with natural purple and functional quality for vacuum fried breaded shrimp. Purple sweet potato flour (PSPF), soy protein isolate (SPI), and xanthan gum were used as coating materials. The effect of the ratio of SPI and xanthan gum on the rheological properties, coating pick-up, color, moisture content, oil content, texture, anthocyanin content and antioxidant activity were investigated. Compared with the control group, it was observed that the batter system with PSPF, SPI and xanthan gum had better rheological properties. The result showed that a ratio of 2:1 for SPI to xanthan gum had the highest coating pick-up value (49.83%), the more attractive purple (a* = 3.07), less oil content (20.55%) and retained higher anthocyanin content (51.71 mg/100 g). Based on the results of anthocyanin content, vacuum fried shrimps were analyzed for antioxidant activity. In the 2,2-diphenyl-1-picrylhydrazyl (•DPPH), hydroxyl (•OH) radical-scavenging assay test, PSPF vacuum fried shrimps showed high free-radical scavenging activity (60.19% for •DPPH and 35.97% for •OH). Therefore, the batter system with PSPF, SPI and xanthan gum is a promising coating material, which is widely used for vacuum fried breaded products, such as pork chop, steak, chicken nuggets and fish fingers.

Abstract Ala-Pro (AP), Ile-Pro-Ala (IPA) and Ile-Pro-Ala-Val-Phe (IPAVF) as DPP-IV inhibitory peptides were purified from Antarctic krill protein hydrolysate (AKH). Diabetic zebrafish model was rapidly induced with combination of high glucose immersing and cholesterol diet for evaluation the three DPP-IV inhibitory peptides activity. Physiochemical indexes including DPP-IV activity, glucose, triglyceride and cholesterol; the relative gene (insa, glucagon and pck1) expressions levels were detected. The results showed that after 15 days of peptides treatment, the physiochemical index levels of peptide groups were significantly higher than that of negative control and showed dose-dependent effect. The insa gene expression level would be increased with the enhancement of peptide concentration, whereas gene expression levels of glucagon and pck1 would be decreased. These results indicated that three peptides all had hypoglycemic effects in different degree. It suggested the potential of AKH containing DPP-IV inhibitory peptides could be as functional food supplement to treat diabetes.

Abstract Sixty Ca-deficient male Wistar rats were divided into six groups to investigate the effect of a calcium-binding bonito hydrolysate (PBH-Ca) on calcium bioavailability in rats, including the normal group, the control groups (PBH + CaCO3 group and the CaCO3 group), and three PBH-Ca groups with doses of 2,000 (PBH-Ca-H group), 1,000 (PBH-Ca-M group), and 500 (PBH-Ca-L group) mg/kg body wt/day. Each group was given the corresponding drug by intragastric administration for 4 weeks. The indices measured included the rate of increase in body weight and body length, apparent calcium absorption rate, serum calcium, serum phosphorus, alkaline phosphatase (ALP) activity, bone volume fraction (BV/TV), bone mineral density (BMD), and trabecular microstructure of the rats scanned by micro-computed tomography. The results showed that PBH-Ca promoted the growth of rats, significantly increased the apparent calcium absorption rate and the number of bone trabeculae, stabilized serum calcium and serum phosphorus content in serum, significantly inhibited ALP activity, decreased the separation of bone trabeculae, accelerated bone growth of rats, and raised the BV/TV and femoral BMD in the rats. These results illustrate that PBH-Ca has promising potential in a high-quality calcium diet.

Abstract To investigate factors that influence free fluoride release in Antarctic krill cuticle, the enzyme properties of a chitinase from Antarctic krill were analyzed to identify its role on free fluoride release from Antarctic krill cuticle. The chitinase was purified by ammonium sulfate precipitation,ion and gel chromatography, and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The molecular mass of the chitinase purified from Antarctic krill was 59.0 kDa and its peptide sequences were similar to chitinase precursor sequences from Penaeus vannamei. The optimal pH of the chitinase was pH 6.5 and temperature 45 °C and exhibited high stability within pH 5.0-6.0 and temperatures below 35 °C. The chitinase activity was increased by Ca2+ and Mg2+, while inhibited by Fe2+, Cu2+ and Co2+. The purified chitinase had Km and Vmax values of 5.88 mmol/L and 2.11 μmol/min·mL, respectively. The endogenous chitinase purified from Antarctic krill could degrade chitin fibers and induced the release of free fluoride from Antarctic krill cuticle. Under experimental conditions, the free fluoride release law in Antarctic krill cuticle can be described by equation: C W = 1 − 0.98 e − 0.0111 t − 0.02 e 0.15 t × 175.52 + 10.80.

Abstract In order to promote the development and application of small molecule oligopeptides from tilapia (SMOT), its anti-fatigue effect was evaluated by using exhaustive swimming in mice. The results showed that compared with the negative control group, SMOT could significantly prolong the exhausted swimming time of mice, reduce blood lactic acid, blood urea nitrogen and malondialdehyde content, and could significantly improve liver glycogen storage status. Meanwhile, the activities of superoxide dismutase and glutathione peroxidase of the mice gavaged with SMOT were significantly higher than those in the negative control group. In addition, SMOT could increase the activity of immune factor IL-2, stimulate the secretion of sIgA and regulate the level of inflammatory factors. So SMOT had significant anti-fatigue effect. Its anti-fatigue effect was exerted by increasing energy reserves, eliminating the accumulation of metabolites, reducing oxidative stress, and improving the body’s immune function.

Abstract Auxis thazard meat was hydrolyzed by alkaline protease. Auxis thazard hydrolysate (ATH) obtained was isolated by ultrafiltration, size exclusion chromatography and reversed-phase high-performance liquid chromatography. Two peptides with high XOD inhibitory activity purified from ATH were identified as Pro-Asp-Leu (PDL, 344.87 Da) and Ser-Val-Gly-Gly-Ala-Leu (SVGGAL, 504.26 Da) by UPLC-MS/MS, which possessed high in vitro XOD inhibitory activity with the IC50 values of 4.37 ± 0.11 mg mL-1 and 5.59 ± 0.09 mg mL-1, respectively. Molecular simulation indicated that PDL and SVGGAL binded to XOD mainly through hydrogen bond and hydrophobic interaction, thereby inhibiting XOD activity. The research results suggested that the two peptides had potential application prospects as a safe XOD inhibitor substance for hyperuricemia treatment.