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The loss of phenolic antioxidants is one of the major problems associated with the food frying process. As temperature increases and heating time is prolonged, losses of both tertiary butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT) are significantly increased. In this work, the effect of different types of free fatty acids (FFA) and the acid value (AV) of soybean oil (SBO) on TBHQ and BHT losses during heating were systematically studied. The results showed that the higher the AV of SBO at 120 or 180°C, the greater the TBHQ loss. The type of FFA also had an observable effect on TBHQ losses at both temperatures, whereas FFA type had no effect on BHT losses. Employing high performance liquid chromatography and liquid chromatography-mass spectra (LC-MS analysis, it was determined that esterification of TBHQ with FFA (C 8:0 , C 18:0 , C 18:1 ) occurred at 120 or 180°C, whereas esterification of BHT with FFA (C 8:0 , C 18:0 , C 18:1 ) in SBO was not observed. Nuclear magnetic resonance analysis showed that esterification occurred at the 4-position of TBHQ.

Summary Novozym‐435‐catalysed esterification of caprylic acid, capric acid and oleic acid with glycerol for the synthesis of medium‐ and long‐chain triglycerides (MLCT) in vacuum and solvent‐free system was investigated in this study. Response surface methodology with a three‐level, four‐factorial design was applied to optimise the enzymatic esterification for the synthesis of MLCT. The optimum conditions were as follows: reaction temperature 90 °C, 4.80 wt% enzyme load (relative to the weight of total substrates) and substrate molar ratio (fatty acids/glycerol) of 3:1 and 12.37 h. Under above‐mentioned conditions, Triglycerides (TG) yield, MLCT and the residual free fatty acids (FFA) content in the product were 93.54%, 72.19% and 4.21%, respectively. The content of caprylic acid, capric acid and long‐chain fatty acids of TG was 24%, 10% and 66%, respectively. Novozym 435 in the study showed no selectivity for the different fatty acids and also could be used 14 times without obvious loss of enzyme activity.

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Abstract. It's widely acknowledged that the application of new media on the design of English writing program in EFL Teaching turns out to be a great progress. Research on new media application in this area mainly focuses on aspects: automatic evaluative system, automatically-generated writing corpus, interactive system between evaluation and revision in synchronous computer-mediated communication. This research aims to investigate how to incorporate these three aspects into a comprehensive program design.