| Aiming to provide data support for the moderate processing of rice bran oil, the physicochemical indexes, composition, colour and trace components of rice bran oil at different processing stages from three different plants in China were determined. The results showed that the acid value of rice bran oil from three plants A, B and C after refining reduced from 24.22, 18.95 mgKOH/g and 17.21 mgKOH/g to less than 0.15 mgKOH/g respectively, and the fatty acid removal rate is more than 99%. The peroxide value was reduced to 0.99, 1.54 mmol/kg and 0.71 mmol/kg respectively. The acid value and the peroxide value of the refined rice bran oil reached the standard of first-grade oil in the GB/T 19112-2003. The change trend of free fatty acid content in rice bran oil in three plants was consistent with that of acid value. The monoglyceride content in rice bran oil decreased by 58.9%-84.9%, mainly removed in the physical deacidification and deodorization, the diglyceride content did not change much, and the triglyceride content increased by 128%-239%. The fatty acid composition of rice bran oil in the three plants did not change significantly during processing. After refining, chlorophyll in rice bran oil was effectively removed, and the colour reached the national standard of first-grade oil. The trace componens of rice bran oil changed greatly during processing, among which oryzanol appeared obvious loss, with the loss rate 80.8%-94.1%, mainly loss in chemical deacidification; sterol loss rate was 21.2%-42.6%, mainly loss in chemical deacidification; vitamin E changed differently, vitamin E content increased by 30.2% in plant A, but reduced by 31.7% and 55.6% in plant B and plant C respectivevly. The loss rate of squalene was 659%-96.3%, mainly occurred in the deodorization. To sum up, the enterprise should adjust the refining process reasonably according to its own position, optimize the refining parameters, and produce the rice bran oil products in line with the enterprise′s pursuit. |
