Effects of infrared radiation combined with heating on grape seeds and oil quality

Abstract

The objective of this work was to determine the effects of infrared radiation combined with heating on grape seeds and oil quality. Experimental results showed that high moisture removal was achieved through infrared radiation heating. After infrared radiation heating for 108 s, the inactivation rates of total aerobic bacterial and total mold-yeast counts of the grape seeds were 1.97 ± 0.12 and 0.62 ± 0.09 log CFU/g, respectively. The maximum microbial reduction was achieved after infrared radiation heating of the grape seeds to 135 ℃ and subsequent holding at 75 ℃ for 60 min. The crude oil yield of samples subjected to these conditions was 10.39%, which was significantly higher ( p < 0.05) than that of the control sample, and their final moisture content was 7.20%. Additionally, increases in the free fatty acid content and peroxide value of the oil were achieved. The iodine value of the oil decreased. In conclusion, surface pasteurization with a high oil yield could be achieved by the combination of infrared radiation heating and the holding process. Consequently, infrared radiation treatment is suggested to be a promising method for the surface pasteurization of grape seeds.