Journal des bioprocédés et des biotechniques

The use of inappropriate temperature-time combinations during roasting of nuts could lead to quality defects, such as burnt taste, dark colour, short shelf-life, rancidity, and poor flavour. The objective of this study was to determine the effect roasting temperature (100-160°C) and time (20-60 min) on colour parameters (L*, a*, and b*- values), Browning Index (BI), Hardness, consumer acceptability and moisture content of both whole cashew-kernel and cashew nut paste using Response Surface Methodology. The experimental runs were established using central composite rotatable design. Second-order polynomial models were developed for predicting the determined product properties. The results showed that CIELAB L*-value of the colour decreased from 54.41 to 41.23 while a*- and b*- values increased from 6.08 to 15.84 and 13.77 to 25.92, respectively, p<0.05 as the temperature and time increased. The moisture content and hardness decreased from 6.35 to 1.02% and 34.24 to 19.94 N, respectively, while BI increased from 47.47 to 97.94 as the temperature and time increased. The results showed that colour parameters (L*, a*, b*-values, BI) of whole cashew-kernel and a*-values of cashew nut paste could be used to monitor the roasting quality of cashew nut. The regression models significantly described the changes in moisture, hardness and colour parameters at p<0.05 (R2=0.96). The recommended range of roasting temperature and time of wholekernel for cashew paste was 145°C and 40 min with desirability of 0.85 which is measure of goodness of fit of RSM model. The study showed that the optimized processing conditions produced acceptable cashew kernel and paste of desirable colour and superior flavour quality with short processing time that will enhance direct and commercial utilization.

The objective of this study was to investigate the effects of grape seed procyanidins extract (GSPE) on lipolysis in rats. Body weight, serum lip level, glucose tolerance, insulin tolerance and gene expression level of FAS, ACC1, Cpt1a and HSL in liver of standard diet (SD) or high fat diet (HFD) treated rats by gavage were measured. The results showed that 150 mg kg-1 d-1 of GSPE is effective in decreasing body weight, serum lip level and blood glucose value of SD and HFD treated rats compared to control. Meanwhile, GSPE can improve the trend of high blood glucose and insulin resistance in obese rats and show the dose-independent manner. Furthermore, application of 150 mg kg-1d-1 GSPE was found to be most effective in suppressing FAS and ACC1 genes expression levels and increasing Cpt1a and HSL genes expression levels in liver of SD (P<0.05) and HFD (P<0.01) treated rats compared with the control treatment. Based on these results, we concluded that GSPE can inhibit the lipid deposition of HFD treated rats, furthermore, it can also influence the gene expression levels of related with lipid metabolism and the glucose-tolerance and insulin-tolerance to co-regulate the lipid metabolism in obese rats.