微波预处理对油莎豆贮藏稳定性及其油脂 脂质伴随物含量的影响Effects of microwave pretreatment on storage stability of tiger nut and lipid concomitant content of its oil

摘要：旨在为提高油莎豆的贮藏稳定性，采用微波对油莎豆进行预处理，研究了冷藏（4 ℃）和常温（20~31 ℃）贮藏条件下油莎豆水分含量、脂肪酶活性及其油脂酸值和过氧化值的变化规律，同时测定了油莎豆油的脂肪酸组成和脂质伴随物含量。结果表明：在常温贮藏或冷藏过程中，油莎豆的水分含量、脂肪酶活性及油莎豆油的酸值、过氧化值均呈一定增长趋势，微波预处理显著降低了油莎豆的水分含量、脂肪酶活性和油莎豆油的酸值；常温贮藏和冷藏120 d后，704 W 处理270 s制备的油莎豆油的酸值（KOH）小于4 mg/100 g，显著低于未经微波预处理的油莎豆油，满足国标（GB 2716—2018）的要求；微波预处理对油莎豆油脂肪酸组成无显著影响，但能提高油莎豆油中生育酚和总酚的含量，其分别在400 W处理270 s、704 W处理210 s时达到最高，为41.70 mg/100 g和10.21 mg/100 g；经微波预处理后，油莎豆油植物甾醇含量总体较空白组有所降低，但保留率在73.05%以上。综上，微波预处理对油莎豆的安全贮藏及其油脂中脂质伴随物的溶出有积极作用。In order to improve the storage stability of tiger nut, the tiger nut was pretreated by microwave and stored at low temperature (4 ℃) and room temperature (20-31 ℃), and the indicators′ change including moisture content and lipase activity of tiger nut, and acid value and peroxide value of its oil were studied. Meanwhile, the fatty acid composition and lipid concomitant content of tiger nut oil were investigated. The results showed that during the storage at room temperature or low temperature, the moisture content, lipase activity of tiger nut and acid value, peroxide value of its oil showed an increasing trend, and microwave pretreatment could significantly reduce the moisture content and lipase activity of tiger nut, and acid value of tiger nut oil. After storage for 120 d at low or room temperature, the acid value of oil from tiger nut treated with the microwave power of 704 W for 270 s was less than 4 mgKOH/100 g, which was significantly lower than the control group, still met the requirements of the national standard (GB 2716-2018). The microwave pretreatment couldn′t affect the fatty acid composition of tiger nut oil, however, rendered the content of tocopherol and total phenol of tiger nut oil to a higher level, reaching their highest at 400 W for 270 s and 704 W for 210 s, respectively, which were 41.70 mg/100 g and 10.21 mg/100 g. After microwave pretreatment, the sterol content of the tiger nut oil was lower than the control group, but the sterol retention rate was above 73.05%. In a word, microwave pretreatment positively impacts the storage safety and the dissolution of lipid concomitant of tiger nut oil.