菜籽油和辛酸酶法合成结构脂质氧化稳定性的研究

Oxidative stability of enzymatically produced caprylic acid and rapeseed oil-based structured lipids

对菜籽油（RSO）和辛酸（CA）酶法合成结构脂质（SLs）的特性和氧化稳定性进行了研究，比较了α-生育酚（α-TOH，25—1000mg／kg）、L-抗坏血酸棕榈酸酯（AP，25—200mg／kg）、特丁基对苯二酚（TBHQ，25～200mg／kg）、二叔丁基对甲酚（BHT，25—200mg／kg）、叔丁基羟基茴香醚（BHA，25～200mg／kg）和没食子酸丙酯（PG，25～200mg／kg）等抗氧化剂对提高SLs氧化稳定性的效果。结果表明，RSO和SLs在110℃下诱导时间（IT）分别为7h和6h，添加α—TOH几乎不能提高SLs的氧化稳定性（r为0．169）；而添加TBHQ、PG、BHA、BHT和AP都能显著提高SLs的氧化稳定性（r分别为0．994，0．948，0．975，0．974和0．985）。SLs和RSO在60℃下加热15d过氧化值（PV）、共轭二烯酸值（CD）和茴香胺值（AV）显著增加，但RSO和SLs的PV、AV增加幅度没有显著差异（P〉0．05），而它们的CD变化幅度有显著差异（P〈0．05）。SLs中CA的插入，一方面增加了饱和脂肪酸，提高了氧化稳定性；另一方面稀释了原料油脂中所含的抗氧化剂浓度，降低了氧化稳定性。

The properties and oxidative stability of structured lipids （SLs） synthesised by rapeseed oil （RSO） with caprylic acid （CA） was studied. The effects of different antioxidants including α- TOH homologues （25 - 1 000 mg/kg）, tertiary butylhydroquinone （ TBHQ, 25-200 mg/kg）, butylated hydroxytoluene （ BHT, 25 - 200 mg/kg）, butylatcd hydroxyanisole （ BHA, 25 - 200 mg/kg）, ascorbyl palmitate （AP, 25 -200 mg/kg） and propyl gallate （PG, 25 ~ 200 mg/kg） on the oxidative stability of SLs were investigated. The results showed that the induction time （IT） of RSO and SLs were 7.0 h and 6.0 h at 110 ℃ respectively, meanwhile, the oxidative stability of SLs by adding cttocopherol was barely improved （r =0. 169）, however, the addition of TBHQ, PG, BHT, BHA or AP could significantly improve oxidative stability of SLs （r was equal to 0.994, 0. 948, 0. 975, 0. 974 and 0. 985 respectively）. There was a considerable increase in peroxide value （PV）, conjugated diene （CD） content and p -anisidine value （AV） of SLs and RSO during heating 15 days at 60 ℃, while no obvious difference（P 〉 0.05 ） in increase degree of PV or AV of RSO and SLs, but significant（P 〈0.05）in CD. Because of the insertion of CA in SLs, the number of saturated fatty acid was increased and the oxidative stability improved; on the other hand, the concentration of antioxidant in raw oil was diluted and the oxidative stability reduced.