| Popis: |
旨在低成本制备零反式、低饱和人造奶油基料油，以高油酸葵花籽油和棕榈硬脂为原料油，采用国内外9种脂肪酶为催化剂催化酯交换制备人造奶油基料油，以固体脂肪含量（SFC）和滑动熔点为考察指标，筛选出一种经济且高效的脂肪酶，采用单因素实验和响应面法优化其酶促酯交换的反应条件，并对比酶促酯交换反应前后油脂的脂肪酸组成、甘三酯（TAG）组成以及热力学性质。结果表明：国产毕赤酵母菌脂肪酶价格低廉且催化活性高；酶促酯交换最优工艺条件为酶添加量17%、反应时间 28 min、反应温度48 ℃；在最优条件下进行10倍放大实验，其5、25 ℃时的SFC分别为22.35%、11.67%；与酯交换前相比，酯交换产物的脂肪酸组成无显著变化，TAG由U3和S3型向S2U和SU2型转化，酯交换率为76.40%，中间熔点的TAG含量增加，高熔点和低熔点TAG含量降低，熔化所需热量减少，利口爽滑感更强。因此，国产毕赤酵母菌脂肪酶价格低廉，适宜作为酶促酯交换制备零反式、低饱和人造奶油基料油的催化剂。Aiming to prepare zero trans and low saturated margarine base oil at low cost, using high oleic acid sunflower seed oil and palm stearin as raw materials, 9 lipases from domestic and foreign as catalysts, margarine base oil was prepared by transesterification, and an economical and efficient lipase based on solid fat content (SFC) and sliding melting point as inspection indicators was selected. Then single factor experiment and response surface methodology were used to optimize the reaction conditions of enzymatic transesterification with the selected lipase as catalyst, and the fatty acid composition, triglyceride(TAG) composition, and thermodynamic properties of the base oil before and after enzymatic transesterification were compared. The results showed that the domestic Pichia pastoris lipase was inexpensive and had high catalytic activity. The optimal conditions for enzymatic transesterification were enzyme addition amount 17%, reaction time 28 min and reaction temperature 48 ℃. The base oil was prepared by 10× magnification experiment under the optimal conditions, and its SFC at 5 ℃ and 25 ℃ were 22.35% and 11.67%, respectively. Compared with the oil before transesterification, the fatty acid composition of transesterification products had no significant change, TAG transformed from U3 and S3 to S2U and SU2, the transesterification rate was 76.40%, the content of TAG at middle melting point increased, the content of TAG at high melting point and low melting point decreased, the heat for melting decreased, and the taste was smoother. Therefore, domestic Pichia pastoris lipase is inexpensive and suitable as a catalyst for the preparation of margarine base oil by enzymatic transesterification. |
