Free fatty acids increase gossypol losses in soybean oil during heating

Abstract

Gossypol is a highly reactive compound present in cotton plant (Gossypium spp.). With the increase of heating temperature and time, gossypol losses increased significantly. In this work, the effect of free fatty acid (FFA) and peroxide value (PV) of soybean oil (SBO) on gossypol losses during heating was systematically studied. Results showed that the higher the content of FFAs of SBO at 120 or 180°C, the greater the gossypol losses. The HPLC and LC/MS analysis suggested that the increase of gossypol losses in SBO was due to the transformation of gossypol in the presence of FFAs at 120 or 180°C. The PV also had an observable effect on gossypol losses at 120 or 180°C, which was ascribed to be the transformation or oxidation of gossypol with hydroperoxides. Practical applications: Due to the toxicity of gossypol, the use of cottonseed oil and cottonseed meal is restricted. It is significantly meaningful to remove gossypol. The primary objective of this study was to investigate the effect of heating temperature and oil quality (AV and PV of oil) on gossypol losses in SBO during heating. More information about the changes of gossypol in oil was achieved, which could be used to guide the processing of cottonseed oil and cottonseed meal. At the same time, the mechanism of gossypol changes could be used to get high quality gossypol. The losses of gossypol in SBO were primarily due to the increasing transformation of gossypol under heating system. Gossypol was non‐volatile and the higher the AV and PV of SBO, the more loss of the gossypol.