不同方法制备的栀子果油的理化性质比较

本实验利用正己烷萃取技术、超临界CO2萃取技术和亚临界低温萃取技术三种方法制备得到了三种栀子果油,并对其主要理化指标、脂肪酸组成、植物甾醇含量、谷维素含量、维生素E含量及氧化酸败时间进行比较分析,以研究不同萃取方法对栀子果油品质的影响。结果表明三种栀子果油的过氧化值为9.38~17.30 mmol/kg,酸值为4.06~14.28 mg KOH/g,皂化值为186.07~198.91 mg KOH/g,碘值为116.43?10-2~130.16?10-2 g I2/g。气相色谱法测定其脂肪酸组成以油酸和亚油酸等不饱和脂肪酸为主,相对含量占76.04~78.00%。栀子果油中植物甾醇和维生素E的含量分别是0.85~3.48%和17.06?10-2~29.80?10-2 mg/g,谷维素含量极少。其中超临界栀子果油的色泽最好,溶剂残留量最少,但酸价最高;正己烷栀子果油中甾醇含量最高,氧化稳定性相对较好;亚临界栀子果油的酸值最低,维生素E含量最高。本文为栀子果油制备方法的选择和精炼提供了理论依据,具有一定的应用意义。

Comparison of the Physicochemical Characteristics of Gardenia Fruit Oils Obtained by Various Methods

Three types of oil samples were obtained from gardenia fruit using n-hexane extraction, subcritical low-temperature butane extraction, and supercritical carbon dioxide extraction, respectively. The effect of the three extraction methods on the oil quality was investigated by comparing the main physicochemical indices, fatty acid composition, phytosterol content, oryzanol content, vitamin E content, and oxidative rancidity time. The results showed that the peroxide values, acid values, saponification values, and iodine values of the three gardenia fruit oils ranged between 9.38~17.30 mmol/kg, 4.06~14.28 mg KOH/g, 186.07~198.91 mgKOH/g, and 116.43~130.16 g I2/100 g, respectively. The results of gas chromatography (GC) suggested that the main fatty acids present in the samples were linoleic acid, oleic acid, and other unsaturated fatty acids, and their relative contents accounted for 76.04~78.00% of the total content of phytocompounds present in the oils. The contents of phytosterol and vitamin E in gardenia fruit oils ranged between 0.85~3.48% and 17.06~29.80 mg/100 g, respectively. The gardenia fruit oil obtained using supercritical carbon dioxide extraction showed the best color quality and the lowest amount of solvent residue, but the highest acid value. The oil extracted by n-hexane had the highest phytosterol content and a relatively good antioxidant activity. The oil obtained from subcritical butane-extraction had the lowest acid value and the highest content of vitamin E. This study reveals a theoretical basis for the selection of extraction and refining methods of gardenia fruit oils, and shows a certain value on application.