Advanced Materials Research Vols. 554-556

Abstract: The aim of this study was to investigate the effect of the catfish bone hydrolysate (CBH) on morphology of bacteria which were observed by atomic force microscope (AFM) and transmission electron microscope (TEM). The CBH was found to inhibit Escherichia coli (E. coli) growth. The CBH at 10 mg/ml caused the significant fragmentariness in the bacterial membrane and a severe volume decrease. A possible mechanism is that CBH damages the structure of bacterial cell membrane which causes E. coli bacteria to die eventually.

Abstract: Naringin esters are paid more attention in medical and functional food industry than naringin due to their higher stability and solubility in lipidic environments. Naringin palmitic acid esters were enzymatically synthesized with naringin and palmitic acid. The effects of solvent type, temperature, concentration and types of enzymes and the molar ratio of substrates on the conversion of naringin were investigated. Novozym 435 performed higher catalytic ability in tert-amyl alcohol in the esterification of naringin with palmitic acid. The conversion yield of naringin increased with the increase of temperature (30-70°C) and of the concentration of enzyme. The structure of the naringin palmitate was characterized by FT-IR, 1H-NMR and HPLC-MS. 1H-NMR spectroscopic analysis indicated the presence of an ester bond on the C-6 of the glucose moiety of naringin molecule.

Abstract: The present study investigated the effect of 1-MCP on bioavailability of Lingwu long jujube stored at 0 °C for 60 days. At the end of the storage, compared with the control samples, Lingwu long jujube treated with 1-MCP exhibited higher Vc bioaccessibility, total phenolic content and free radical scavenging capacity, which demonstrated that 1-MCP treatment could provide a better effect on maintaining the bioavailability of Lingwu long jujube.

Abstract: The present study investigated the influence of 1-methylcyclopropene (1-MCP) and salicylic acid (SA) on sugars, organic acids and amino acids in peach (Prunus persica (L.) Batsch cv. Okubao) during postharvest ripening. The results of principal components analysis (PCA) showed 1-MCP increased the levels of fructose, sucrose, glucose and inositol, but decreased citric acid and oxalic acid levels, whereas no significant difference was observed in SA-treated fruit compared with controls. The result of partial least square regression (PLSR) showed that glucose and asparagine were shown to be strongly correlated with sensory sweetness, sweetness/sourness ratio and overall flavor, whereas sucrose and inositol were significant positive correlated with sourness of peach fruit.

Abstract: This paper investigated the effects of 2 g/L acetic acid fumigation technology on the value of L*, a*, b* and the contents of blue pigment, yellow pigment and allicin of “Laba” garlic in different product forms. “Laba” garlic was prepared by three different treatments: (1) traditional dip (control sample); (2) “Laba” garlic cloves were fumigated by 2 g/L acetic acid; (3) “Laba” garlic bulbs were fumigated by 2 g/L acetic acid. During process, all the treated samples were maintained at appropriate conditions (dark, 20 °C). After 10 days of process, the value of L*, a*, b* and the contents of blue pigment, yellow pigment and allicin of “Laba” garlic in different product forms were measured. Interestingly, the results presented that the value of L*, b* and the contents of blue pigment, yellow pigment and allicin of “Laba” garlic prepared by dry process were higher than them within traditional dip samples. The technology of dry process might be a novel process method to produce “Laba” garlic in the future.

Abstract: Oxidative stress and the implications have been highlighted in the pathogenesis of many neurodegenerative disorder of the brain including Alzheimer’s disease. Nowadays, the interests in the protective role of several plants extracts are growing up. Plants antioxidants ability includes the inhibition of reactive oxygen species (ROS) overproduction and up-regulation of endogenous antioxidant defences. In this study, neuroblastoma cell line, SH-SY5Y was used to determine the neuroprotective effect of the leaves and figs of aqueous extract of four varieties of Ficus deltoidea namely var kunstleri, var angustifolia, var deltoidea, and var intermedia. The study showed the positive interaction between the inhibition of free radical with the neuroprotective effect against hydrogen peroxide (H2O2)-induced in SH-SY5Y cells.

Abstract: Soybean meal was hydrolyzed by Neutrase in research. DPPH radical scavenging rate, hydroxyl radical scavenging rate and reducing power were chosen as the response values. Then the optimal technique was established through a systemic research on the influencing factors, including hydrolysis temperature, time, pH, enzyme amount and substrate concentration. Results show that the soybean meal can be effectively hydrolyzed by Neutrase, and the optimal technique conditions were temperature 40°C, time 4h, pH 7.0, enzyme amount 48,000U/g substrate, and substrate concentration 6%. Under these conditions, reducing power is 0.954.

Abstract: Tilapia frames were subjected to enzymatic hydrolysis using Flavouzryme and Papain with a ratio of 2:1. The relationship of temperature (40 to 60°C), enzyme: substrate ratio (0.5% to 4.5%), initial pH (6.0 to 8.0) and hydrolysis time (1h to 9h) to the degree of hydrolysis were determined. The enzymatic hydrolysis was optimized for maximum degree of hydrolysis using surface response methodology. The optimum conditions for enzymatic hydrolysis of tilapia frames were temperature 53°C, enzyme : substrate ratio of 3.5%, initial pH 7.2, and reaction time 7h. Under these conditions a degree of hydrolysis of 40.01% were obtained. The yield of free amino acids in the hydrolysate was 46.61mg/g tilapia frames. The flavor amino acids and essential amino acids occupied up to 31.8% and 49.0% of the total free amino acids respectively. The hydrolysate of waste tilapia frames showed good potential for applications such as protein supplementation in food system.

Abstract: Changes in structure property of myofibrillar protein from porcine longissimus dorsi were monitored during 12 months of storage at –5, –18, –26, –35 and –70 °C. With the extended frozen time at the same temperature, Ca2+-ATPase activity, K+-ATPase activity, total sulfhydryl content reactive sulfhydryl content decreased (P < 0.05), surface hydrophobicity (S0-NAS) increased (P < 0.05). Meanwhile, stucture of myofibrillar protein was more susceptible to high frozen storage temperature than low frozen storage temperature. There was markedly loss in band intensity of myosin heavy chain, actin, paramyosin, troponin, and propomyosin from frozen meat within frozen storage.

Abstract: A total of 69 gram-positive, catalase-negative strains isolated from Inner Mongolia traditional meat sausages were characterized in respect to their technological properties, including acid production, salt and nitrite tolerance, gas, slime and H₂S production, hydrolysis of arginine and biogenic amine production. All of the isolated strains decrease the pH below 5.0 after 24h of cultivation. All isolates are able to grow with 6.5% NaCl or with 150mg L^-1 NaNO₂ and 51 isolates are able to grow with 10% NaCl. All isolates don’t produce gas and slime. 54 isolates don’t produce H₂S. 23 isolated strains don’t produce NH3 from arginine, and 40 isolates don’t produce biogenic amine. Consolidation of these results, 8 strains show the best technological properties to be used as starter culture for sausage production. The bacterial selected are then subjected to biochemical tests using the API 50 CH and they are identified as 6 Lactobacillus planarum and 2 Lactobacillus curvatus.