油橄榄叶醇提取物对煎炸油品质的影响

Effects of ethanol extract of olive leaves on the quality of oil during frying process

为促进橄榄油产业加工副产物的综合利用,探究了油橄榄叶醇提取物(EEOL)对煎炸薯条过程中大豆油品质的影响。以DPPH和ABTS+自由基清除率为指标,评价EEOL体外抗氧化能力,随后将EEOL加入大豆油中,于180℃进行30 h间歇煎炸,以特丁基对苯二酚和茶多酚为对照,对煎炸油的基本理化指标、色泽、脂肪酸组成进行分析。结果表明:EEOL中总酚含量为(84.47±0.02)mg/g,总黄酮含量为(35.03±0.03)mg/g;DPPH和ABTS+自由基清除率IC 50分别为15.01μg/mL和43.13μg/mL;煎炸结束后,添加质量分数为0.04%EEOL的煎炸油的酸价增加量与空白组相比降低48.24%,p-茴香胺值降低7.46%,共轭二烯含量降低29.41%,共轭三烯含量降低15.03%,总极性化合物含量降低38.63%,过氧化值波动范围(0.51~1.03 mmol/kg)低于空白组(0.24~1.03 mmol/kg),同时延缓煎炸油红值和黄值的升高及不饱和脂肪酸的氧化损失。综上,EEOL可作为一种具有开发价值的天然抗氧化剂应用到油脂行业中。

Edible vegetable oils are prone to deteriorate through complex chemical reactions during frying.To promote the widespread use of low-cost by-products from the olive oil industry in the oil processing industry,the effects of ethanol extract of olive leaves(EEOL)on the quality of soybean oil during the deep frying of French fries were investigated.The in vitro antioxidant capacity of EEOL was evaluated using the scavenging rate of DPPH and ABTS+free radicals as a key indicator.Then,EEOL was added to soybean oil for 30 h of intermittent frying at a constant temperature 180℃,a process that mimicked real-world commercial frying patterns,while soybean oil enriched by TBHQ and tea polyphenols was used for comparison.The basic physicochemical indices,color,and fatty acid composition of the soybean oils have been analyzed to comprehensively evaluate the stability of frying oil.The results showed that the total phenolic and total flavonoid contents of EEOL were(84.47±0.02)mg/g and(35.03±0.03)mg/g,respectively.The IC 50 of DPPH and ABTS+radical scavenging activity were 15.01μg/mL and 43.13μg/mL,respectively.Compared with the blank group,the EEOL-added soybean oil decreased the increase of acid value by 48.24%,p-anisidine value by 7.46%,conjugated diene by 29.41%,conjugated triene by 15.03%,total polar compounds by 38.63%,while the fluctuation range of the peroxide value(0.51-1.03 mmol/kg)was lower than the blank group(0.24-1.03 mmol/kg).Meanwhile,the increase in red and yellow values of soybean oil and the oxidative loss of polyunsaturated fatty acids were also significantly delayed.In summary,the addition of EEOL as an antioxidant in frying oil showed good performance in delaying the thermal oxidation of oil and improving the quality of oil.Therefore,EEOL had the potential to act as a source of natural antioxidants to replace synthetic antioxidants to prevent oxidation of frying oil.