不同工艺制备核桃油品质比较及相关性分析

Quality comparison of walnut oil extracted by different processes and correlation analysis of quality indexes

对溶剂提取、低温压榨两种方法提取的核桃油感官品质(色泽)、理化营养品质(水分及挥发物含量、脂肪酸组成、VE异构体含量、植物甾醇各组分含量)及加工品质(诱导时间、过氧化值、酸值、脂肪酸比例模式)进行测定并对其品质指标进行相关性分析。结果表明:低温压榨核桃油的加工品质较好,其诱导时间(1.92 h)较长,过氧化值(1.44 mmol/kg)和酸值(KOH)(0.69 mg/g)较低,且O/L(0.33)较高;其油酸含量(19.97%)及UFA含量(90.96%)较高,营养品质相对较好。色泽与诱导时间呈极显著正相关;油酸含量与亚油酸含量呈极显著负相关(r=-0.944);油酸、亚油酸、MUFA、PUFA、O/L与诱导时间的相关关系均达到极显著水平。

The sensory qualities （colour）, physicochemical and nutritional qualities （moisture and vola- tile matter contents, fatty acid composition, vitamin E isomer and phytosterol contents） and processing qualifies （ induction time, peroxide value, acid value and fatty acid proportional modes） of the solvent - extracted walnut oil and the cold - pressed walnut oil were determined. The correlation analysis of the quality indexes of the walnut oils was conducted. The results showed that the cold -pressed walnut oil had better processing quality with longer induction time（ 1.92 h）, lower peroxide value （ 1.44 mmol/kg） and acid value （0.69 mgKOH/g）, higher ratio of oleic acid to linoleic acid （0.33）, and higher contents of oleic acid （ 19.97% ） and unsaturated fatty acids （90.96%） than solvent - extracted walnut oil. Furthermore, colour and induction time were markedly positive correlated, while oleic acid and linoleic acid were significantly negative correlated （ r = - 0.944）, and induction time was remarkably correlated with oleic acid, linoleic acid, monounsaturated fatty acids, polyunsaturated fatty acids and ratio of oleic acid to linoleic acid.