不同贮藏条件下核桃及其油脂品质的变化分析

研究了不同贮藏条件对核桃及其油脂品质的影响。将新鲜核桃分别贮藏于常温、低温、蜡封与保鲜袋包装中,通过测定核桃水分含量、粗蛋白质含量、粗脂肪含量、脂肪酶活力以及核桃油酸值、过氧化值、脂肪酸组成,分析不同贮藏条件对核桃及其油脂品质的影响。结果表明:核桃油中饱和脂肪酸约占9%,不饱和脂肪酸含量高达约91%;蜡封贮藏条件下的核桃在贮藏90 d后,水分含量、粗蛋白质含量、粗脂肪含量下降速率最慢,分别减少8.09、0.7、2.16个百分点,核桃油酸值(KOH)与过氧化值增长速率较慢,分别为0.44 mg/g、2.19 meq/kg;蜡封贮藏条件下核桃脂肪酶活力先上升后下降,且整体活性较低;蜡封贮藏条件下核桃油中不饱和脂肪酸含量下降幅度最低,为1.03个百分点。在降低温度的基础上采用蜡封的密封方式,能够一定程度上隔绝氧气,对核桃及其油脂的保存有积极意义。

Analysis of quality changes of walnut and walnut oil under different storage conditions

The effects of different storage conditions on the qualities of walnut and walnut oil were studied.Fresh walnuts were stored under four different storage conditions, such as normal temperature, low temperature, wax-sealing package and fresh-keeping bag package. Through the determination of moisture content, crude protein content, crude fat content and lipase activity of walnut, and acid value, peroxide value and fatty acid composition of walnut oil, the effects of different storage conditions on the qualities of walnut and walnut oil were analyzed.The results showed that saturated fatty acid content accounted for about 9% in walnut oil, and unsaturated fatty acid content was up to 91%. The decrease rates of contents of moisture, crude protein, and crude fat in walnut in wax-sealing package after storing for 90 d were the slowest with 8.09, 0.7, 2.16 point percentage, respectively, and acid value and peroxide value of walnut oil had the slowest growth rates with 0.44 mgKOH/g and 2.19 meq/kg respectively. Lipase activity of walnut in wax-sealing package increased at first and then decreased, and overall activity was low. The content of unsaturated fatty acid in walnut oil in wax-sealing package had the lowest reduction range by 1.03 point percentage.The wax-sealing based on lower temperature could isolate oxygen to a certain extent, and had a positive significance for the storage of walnut and walnut oil.