不同热处理和贮存条件对调和油品质的影响

Effects of Different Heat Treatments and Storage Conditions on Quality of Blend Oil

利用油脂酸价(Acid value,AV)、过氧化值(Peroxide value,POV)、脂肪酸组成及流变特性,研究不同处理条件对油脂品质的影响。不同处理条件下,AV与POV均随时间延长而升高。200℃以上高温烹调和光照贮存的油脂AV和POV分别高于微波处理和高温贮存组,并随烹饪温度和光照的增加而迅速增加,最高分别达到1.17 mg/g与22.75 mmol/kg;处理时间和温度、热处理方式与光照对脂肪酸含量都有影响,变化趋势不尽相同。高温长时间处理使油酸和亚油酸含量降低,300℃处理20 min,含量从38.94%和31.46%降为37.76%和30.53%,而亚麻酸的含量由0.26%增加至0.28%,EPA和DHA多不饱和脂肪酸的含量也有增加。高温和光照条件下长时间储存,以上不饱和脂肪酸含量均降低;不同处理后的油脂流变学特性不随剪切力的改变而改变,200℃以上高温烹调和微波组的油脂粘度随处理时间的增加,呈先降低后增加趋势,贮存组的油脂粘度随处理时间的延长而一直呈现增加趋势。

The effects of different treatment conditions on oil quality were studied by using acid value(AV),peroxide value(POV),fatty acid composition and rheological properties.Under different treatment conditions,both AV and POV showed an increasing trend with time.The AV and POV of the high temperature cooking group and the light storage group above 200℃ were higher than those of the microwave treatment group and the high temperature storage group,respectively.With the increase of cooking temperature and illumination,the AV and POV increased rapidly,and their highest values were reached under the processing conditions,1.17mg/g and 22.75mmol/kg,respectively;treatment time and treatment temperature,heat treatment method and light had an effect on fatty acid content,and the change trend was not nearly the same.Long-term treatment at high temperature reduced the content of oleic acid and linoleic acid.After treatment at 300℃ for 20 min,the content of oleic acid and linoleic acid decreased from 38.94% and 31.46% to 37.76% and 30.53%,respectively,while the content of linolenic acid increased from 0.26% to 0.28%,and the content of EPA and DHA polyunsaturated fatty acids also increased.For the long-term storage under high temperature and light conditions,the above unsaturated fatty acid content was reduced;the rheological properties of the oil after different conditions were not changed with the change of shear force for the high temperature cooking group and the microwave group above 200℃.The viscosity of fat increased with the increase of treatment time,and then decreased.The viscosity of the oil in the storage group increased with the treatment time.