Effects of Heat Treatment and Antioxidant Tert-Butylhydroquinone Pretreatment on Digestive Characteristics of Meat Oil of Antarctic Krill

In order to study the effects of heat treatment and antioxidant addition on the digestive characteristics of meat oil of Antarctic krill, an in vitro gastrointestinal digestion model was established to measue the changes of peroxide value, acid value, malondialdehyde content, astaxanthin content and fatty acid composition of the oil in untreated blank group, 85 ℃ heat treatment group and 85 ℃ heat treatment with tert-butylhydroquinone (TBHQ) group after digestion. The results showed as follows: After gastrointestinal digestion, the peroxide value, acid value and malondialdehyde content of oil in blank group significantly increased (P<0.05), while astaxanthin content significantly decreased (P<0.05), fatty acid composition had no significant change, indicating that gastrointestinal digestion could accelerate the primary and secondary oxidation processes of oil. The changes of peroxide value, malondialdehyde content, acid value, astaxanthin content and fatty acid composition of oil digested by gastrointestinal tract in the 85 ℃ heat treatment group were basically consistent with that in the blank group. However, compared with the blank group, the malondialdehyde content in the 85 ℃ heat treatment group was significantly higher than that in the blank group after intestinal digestion (P<0.05), indicating that the 85 ℃ heat treatment accelerated the secondary oxidation process of lipid digestion. The changes of peroxide value, malondialdehyde content, acid value, astaxanthin content and fatty acid composition in TBHQ group after gastrointestinal digestion were basically consistent with those in 85 ℃ heat treatment group. However, after digestion by gastrointestinal tract, the peroxide value and malondialdehyde content decreased, indicating that TBHQ played an antioxidant role in this process. These results indicated that the gastrointestinal digestion process promoted the oxidation of meat oil of Antarctic krill, and heat treatment intensified the secondary oxidation process of meat oil of Antarctic krill in the gastrointestinal tract, and the addition of TBHQ could effectively slow down the oxidation of oil caused by heat treatment in the gastrointestinal tract.