氧气含量与光照对薏仁米储藏中脂肪氧化的影响

探讨不同氧气含量和光照条件下薏仁米贮藏过程中水分含量、脂肪酸值、过氧化值、丙二醛、脂肪酶活动度及电导率等指标的变化对薏仁米脂肪氧化的影响。结果表明:脂肪酸值、过氧化值、丙二醛、电导率能灵敏体现薏仁米不同储藏时间、氧气含量和光照条件下的脂肪氧化。随着储藏时间的延长,到180 d时,虽然氧气含量低或未检出,脂肪酸值、过氧化值、丙二醛、电导率与初始值比增加了113.6%、103.62%、6.32%和18.91%,在一定的氧气含量下,各指标比氧气含量低或未检出样增加了14.86%、52.34%、52.92%和24.07%;在避光下,薏仁米储藏180d时脂肪酸值、过氧化值、丙二醛和电导率分别增加了84.85%、132.33%、31.34%和12.95%;受光照条件的影响,这四项指标比避光下分别增加了28.24%、38.72%、27.53%和5.09%。氧气含量低或未检出及避光下不能避免薏仁米储藏的脂肪氧化,氧气含量与光照强度加速薏仁米储藏中的脂肪氧化,在放脱氧剂的条件下,抽真空、充CO_2或N_2和避光能减缓薏仁米中脂肪氧化的速度。

Effect of Oxygen Content and Light on Fat Oxidation during Storage of Coix Seeds

The effects of changes in water content, fatty acid value, peroxide value, malondialdehyde content, lipase activity and electrical conductivity during the storage of coix seeds under different oxygen and light conditions, on the fat oxidation of coix seeds were investigated. The results showed that the fatty acid value, peroxide value, malondialdehyde content and electrical conductivity can reflect sensitively the fat oxidation of coix seeds under different storage times, oxygen contents and light conditions. With the storage time extending to 180 days, the fatty acid value, peroxide value, malondialdehyde content, electrical conductivity increased by 113.6%, 103.62%, 6.32% and 18.91, respectively, compared with the initial values, even though the oxygen content was low or not detected. At a certain level of oxygen , the indicators were 14.86%, 52.34%, 52.92% and 24.07% higher than those when the oxygen content was low or undetected; During storage of coix seeds in the dark for 180 days, the fatty acid value, peroxide value, malondialdehyde content and electrical conductivity increased by 84.85%, 132.33%, 31.34% and 12.95%, respectively. Under the influence of light conditions, these four indicators increased by 28.24%, 38.72%, 27.53% and 5.09 respectively. At a low or undetected level of oxygen, oxidation of fat could not be avoided during storage of coix seeds. The presence of oxygen and light accelerated the oxidation of fat during storage of coix seeds. In the presence of a deoxidizer, vacuum, CO2 or N2 and keeping out of light could slow down the rate of fat oxidation in coix seeds.