不同储藏温度下蒸谷米生化特性指标的变化研究

Study on biochemical characteristics changes of parboiled rice under different storage conditions

为研究蒸谷米在储藏期间的生化特性指标的变化规律,探究其储藏特性,以同批次稻谷加工成的大米为对照,将其与蒸谷米分别置于低温(15℃)、常温(25℃)和高温(35℃),相对湿度均为75%条件下储藏,定期取样并对样品的丙二醛含量、还原糖含量、碱消值、过氧化物酶活性、脂肪氧化酶活性、脂肪酸值进行测定。结果表明:在300 d内,15℃和25℃条件下,蒸谷米的丙二醛含量升高,35℃条件下,其丙二醛含量下降;3种储藏条件下,蒸谷米的还原糖和碱消值均下降,过氧化物酶活性基本不变,脂肪氧化酶活性略微降低,脂肪酸值升高;随着储藏时间的延长,3种不同温度下储藏的蒸谷米,其生化特性指标整体变化不大,而大米在3种温度下,其生化特性指标均呈现了较大的变化。由多因素方差分析可知,大米的生化特性指标极易受储藏条件的影响;储藏时间对蒸谷米的丙二醛含量、过氧化物酶活性和脂肪氧化酶活性无显著影响,储藏温度以及储藏时间和储藏温度交互作用除对蒸谷米的脂肪酸值有极显著影响外,对其余各指标均无显著影响。与大米相比,蒸谷米不易受外界环境的影响,能更好地保持储藏品质,具有良好的储藏稳定性,在需长期储藏时,可选择蒸谷米。

In order to study the changes of biochemical characteristics of parboiled rice during storage and explore its storage characteristics,taking the milled rice processed from the same batch of rice as a reference,the milled rice and parboiled rice samples were stored under the conditions of low temperature(15 ℃,RH 15%),normal temperature(25 ℃,RH 15%),and high temperature(35 ℃,RH 15%).The malondialdehyde content,reducing sugar content,alkali elimination value,peroxide activity,lipoxygenase activity and fatty acid value of the samples were regularly measured to explore the change rule of each index.The results showed that the malondialdehyde content of parboiled rice increased at 15℃ and 25℃,and decreased at 35℃;the reducing sugar and alkali consumptive value of parboiled rice decreased at15℃,25℃ and 35℃,the peroxidase activity remained basically unchanged,the lipoxygenase activity slightly decreased,and the fatty acid value increased during the storage period.With the extension of storage time,the biochemical characteristics of milled rice stored at three different temperatures did not change as a whole,while the biochemical characteristics of parboiled rice at three temperatures showed great changes.The difference analysis showed that the biochemical characteristics of milled rice were easily affected by storage conditions,while the storage time had no significant effect on the malondialdehyde content,peroxidase activity,or lipoxygenase activity of parboiled rice.Storage temperature and the interaction of storage time and storage temperature had significant effect on the fatty acid value of parboiled rice,but had no significant effect on other indexes.Compared with milled rice,parboiled rice is not easy to be affected by the external environment.Its storage quality can be better maintained and its storage stability is good.Therefore,for long-term storage,steamed rice is preferred.