[Analysis of fat content and fatty acid composition of aquaculture products in Hainan Province].

OBJECTIVE: To investigate the composition of fat and fatty acid in 12 kinds of aquaculture products in Hainan Province. METHODS: A total of 12 aquatic products were monitored in 8 breeding bases in Hainan Province, the edible parts were tested for fat and fatty acid. The content and composition of fat and fatty acid were analyzed. RESULTS: A total of 12 aquaculture products were monitored, including 6 freshwater aquaculture products and 6 mariculture aquatic products. The contents of crude fat and total fatty acid(TFA) ranged from 1.2 to 20 g/100 g edible and 1.0 to 15 g/100 g edible, and they were positively correlated(r=0.989, P<0.01). A total of 18-30 fatty acids were detected. Among them, 12 were saturated fatty acids(SFA), ranging from 0.34 to 6.4 g/100 g edible, mainly palmitic acid, eight were monounsaturated fatty acids(MUFA), mainly oleic acid. Ten were polyunsaturated fatty acids(PUFA), ranging from 0.28 to 2.6 g/100 g edible, It was mainly composed of linoleic acid(LA), docosahexaenoic acid(DHA), α-linolenic acid(ALA) and eicosapentaenoic acid(EPA). CONCLUSION: The composition of fatty acid in aquaculture products in Hainan Province is mainly unsaturated fatty acids(UFA), and most aquatic products are rich in n-3PUFA, and the ratio of n-6PUFA to n-3PUFA is less than 6, which has high nutritional and health value, and is beneficial to the nutritional diet balance of of population.

Strain Rate Behavior in Tension of Reinforcing Steels HPB235, HRB335, HRB400, and HRB500.

The strain rate effect of reinforcing steel bars is generally indispensable for modeling the dynamic responses of reinforced concrete structures in blast and impact events. A systematic experimental investigation was conducted on the strain rate behavior of reinforcing steel bar grades HPB235, HRB335, HRB400, and HRB500 which are widely used in the field of civil engineering in China. The dynamic testing was performed using a servo-hydraulic Instron VHS160/100-20 in a strain rate range from 2 to 75 s-1. Stress-strain curves at preset strain rates were obtained. The test data were then used to derive the parameters in a model based on the dynamic increase factors (DIFs) of strengths and the Johnson-Cook constitutive model. Results indicated that a significant strain rate effect was observed for the four rebar grades. The dynamic yield strengths increased from 13% to 41% and their ultimate strengths improved from 9% to 19% in the strain rate range during testing. The strain rate behavior of the four rebar grades could be appropriately predicted using the parameters in the model based on the DIFs of strengths and the Johnson-Cook model.