Applied Mechanics and Materials Vol. 140

Abstract: Use peanut protein powder as the raw material, the five kinds of peanut antioxidant peptides (abbreviated as AP, FP, PP1, NP and PP2, respectively) were obtained through steps of Viscozyme pretreatment and Alcalase, Flavourzyme, Protamex, Neutral protease and Papain hydrolysis, respectively. Four types of antioxidation activities evaluation methods in vitro including scavenging of DPPH free radical, reducing power, iron ion chelation and anti-lipid peroxidation were presented to evaluate the antioxidation activities of peanut antioxidant peptides. The order of antioxidation activities of five antioxidant peptides was PP2>AP>FP>PP1>NP by comprehensive analysis of the antioxidation experimental results. The results indicated that the optimum proteolytic enzyme for preparing antioxidant peptide was papain. Among the five antioxidant peptides, PP2 had the most antioxidation activities of scavenging of DPPH free radical, reducing power, anti-lipid peroxidation. Therefore, the research and development of antioxidant peptide with the antioxidative function by using papain is an effective approach to further exploit peanut protein.

Abstract: To investigate the in vitro antioxidation and antimicrobial activity of the lac dye, in this study, three free radicals DPPH·, ABTS⁺ and O₂^ˉ· are used as the test objects to evaluate the free radial scavenging ability of the lac dye by comparing the absorbance change of free radical solution under specific wavelength. The results showed that, the lac dye has scavenging activity on DPPH· and ABTS⁺ , but has no scavenging activity on O₂^ˉ·; when the lac dye reached a certain concentration, its scavenging rate on DPPH· and ABTS⁺ can be as high as 68% and 87% respectively, with the antioxidant activity respectively 0.20 times and 3.42 times of that of the ascorbic acid, indicating that the lac dye is a kind of natural pigment of a certain scavenging activity on free radicals.

Abstract: Defatted soybean meal was hydrolyzed by Alcalase in research. Anti-linoleic acid peroxidation capacity was chosen as the response values. Then the optimal technique was established through a systemic research on the influencing factors, including enzymolysis temperature, time, proteases concentration and substrate concentration, etc. Results showed that the defatted soybean meal could be effectively hydrolyzed by the alkali protease Alacase2.4 L, and the optimal technique conditions were temperature 55°C, time 3h, pH 8.0, proteases concentration 19,200U per gram substrate, and substrate concentration 8%. The anti-linoleic acid peroxidation capacity of enzymatic hydrolysates could be 34.16%, with the hydrolyte degree of 35.0 %.

Abstract: Biological monitoring for arsenic(As) is usually based upon a determination of urine, blood, nail and hair arsenic concentration, however, saliva has been suggested as a non-invasive biological matrix for assessing exposure. To further evaluate the potential utility of saliva for arsenic biomonitoring, Atomic Fluorescence Spectrometry(AFS-230) and Inductively Coupled Plasma Mass Spectrometer (ICP-MS) were used to evaluate the concentration of arsenic in drinking water, saliva and urine in endemic arsenicosis area in Shanyin County of Shanxi Province. The results showed that the arsenic concentration in drinking water was 0.55-720.0ug/L, and there were 66.67% samples above the arsenic level (50μg/L) of standards for drinking water quality. The median value of arsenic in drinking water was 127.22 μg/L. The salivary and urinary arsenic both can reflect the exposure of arsenic in drinking water. Additionally, there was a significant positive association of salivary arsenic compared with arsenic in drinking water (r=0.674, P<0.05)and urinary arsenic(r=0.794, P<0.05). These results demonstrated that, similar to urinary arsenic, salivary arsenic also can be used as a biomarker for assessing human exposue to arsenic.

Abstract: Rosmarinic acid, a polyphenol-containing hydroxy acid, is believed to have many activities, such as anti-oxidation, anti-inflammatory, immune regulation, anti-thrombosis generation, anti-baterial, anti-virus and anti-depressants. It is used commercially for food preservation. Here we report that rosmarinic acid extended the lifespan of the model organism Caenorhabditis elegans (C. elegans) under normal culture conditions (25°C) and under thermal stress (35°C). C. elegans dieted rosmarinic acid with final concentration 50mg / L and 100mg / L under two kind of conditions were shown to have extended lifespan compared to the control without rosmarinic acid uptake. Furthermore, the rosmarinic acid with final concentration 50mg/L had more obvious longevity-extending effect. The precise mechanism (s) responsible for this remains to be identified. To study the anti-senescence molecular mechanism of rosmarinic acid, semi-quantitative RT-PCR was used to analyze the expression of aging-associated genes such as daf-16 and heat shock protein 16.2 (hsp-16.2). As a result, the expression of aging-associated genes was up-regulated. This study suggested that rosmarinic acid significantly extends the lifespan of C. elegans through up-regulating some genes' expression such as daf-16 and hsp-16.2 which will provide important reference for antiaging research of rosmarinic acid.