Studies of Reaction Variables for Lipase‐Catalyzed Production of Alpha‐Linolenic Acid Enriched Structured Lipid and Oxidative Stability with Antioxidants

  Alpha‐linolenic acid (ALA) enriched structured lipid (SL) was produced by lipase‐catalyzed interesterification from perilla oil (PO) and corn oil (CO). The effects of different reaction conditions (substrate molar ratio [PO/CO 1:1 to 1:3], reaction time [0 to 24 h], and reaction temperature [55 to 65 °C]) were studied. Lipozyme RM IM from Rhizomucor miehei was used as biocatalyst. We obtained 32.39% of ALA in SL obtained under the optimized conditions (molar ratio—1:1 [PO:CO], temperature—60 °C, reaction time—15 h). In SL, the major triacylglycerol (TAG) species (linolenoyl‐linolenoyl‐linolenoyl glycerol [LnLnLn], linolenoyl‐linolenoyl‐linoleoyl glycerol [LnLnL]) mainly from PO and linoleoyl‐linoleoyl‐oleoyl glycerol (LLO), linoleoyl‐oleoyl‐oleoyl glycerol (LOO), palmitoyl‐linoleoyl‐oleoyl glycerol (PLO) from CO decreased while linolenoyl‐linolenoyl‐oleoyl glycerol (LnLnO) (18.41%), trilinolein (LLL) (9.06%), LLO (16.66%), palmitoyl‐linoleoyl‐linoleoyl glycerol (PLL) (9.69%) were increased compared to that of physical blend. Total tocopherol content (28.01 mg/100 g), saponification value (SV) (192.2), and iodine value (IV) (161.9) were obtained. Furthermore, oxidative stability of the SL was also investigated by addition of 3 different antioxidants (each 200 ppm of rosemary extract [SL‐ROS], BHT [SL‐BHT], catechin [SL‐CAT]) was added into SL and stored in 60 °C oven for 30 d. 2‐Thiobabituric acid‐reactive substances (TBARS) value was 0.16 mg/kg in SL‐CAT and 0.18 mg/kg in SL‐ROS as compared with 0.22 mg/kg in control (SL) after oxidation. The lowest peroxide value (POV, 200.9 meq/kg) and longest induction time (29.88 h) was also observed in SL‐CAT.