自发气调方式对核桃鲜贮及核桃仁品质的影响

Effect of Modified Atmosphere Package Conditions on Preservation of Green Walnut Fruit and Kernel Traits

摘要:

为了确定青皮核桃自发气调的准确方式，以“辽宁2号”、“西扶2号”核桃鲜果为试材，PE50包装下被动自发气调（pPE50）为对照，另设主动自发气调（aPE50）、80~85% CO2脉冲自发气调（CO2+pPE50）两种处理，采取青皮核桃--湿鲜坚果二步法，在0～1 ℃，相对湿度70~80%条件下冷藏。两个品种均以aPE50包装袋内气体浓度变化最大，贮藏18 d达到相对稳定后，O2、CO2体积分数均分别为4.6~5.4%，9.6~11.0%。贮藏80 d后，两个品种的青皮果实腐烂率均以aPE50最低，分别为12.2%、15.7%；核桃仁感观品质下降以aPE50慢于对照，CO2+pPE50快于对照；两个处理果实的青皮总酚、类黄酮等物质的含量均极显著高于对照（p<0.01）。湿鲜坚果继续贮藏期间，aPE50核桃仁酸价、过氧化值上升最慢，总酚、类黄酮含量后期增加，丙二醛（MDA）含量和脂氧合酶（LOX）活性持续最低，aPE50被选为更适合青皮核桃保鲜的自发气调方式。

Abstract:

To explore the proper mode of modified atmosphere package for fresh walnut preservation, green walnut fruit of cv. Liaoning2 and Xifu2 were harvested and stored in active modified atmosphere package with PE50 (aPE50) and pPE50 with pretreatment of 80~85% CO2 pulse (CO2 + pPE50), passive modified atmosphere package with PE50 (pPE50) was as control. Then they were stored with two-step way at 0~1 ℃, with RH of 70~80%.The results showed that aPE50 package presented most effective function of atmosphere modification on both varieties, after 18d-storage when they reached stable relatively, the volume fraction of O2 and CO2 were 4.6~5.4% and 9.6~11.0%, respectively . Storage decay rates of the fruit from aPE50 were the lowest, being 12.2% in Liaoning 2 and 15.7% in Xifu 2 after 80 d .Sensory quality decline of kernel was slower in aPE50 and faster in CO2+pPE50 compared with control. Content of total phenols, flavonoids, tannin, ascorbic acid(VC), reduced glutathione (GSH) in green husk from both aPE50 and CO2 + pPE50 were greater statistically than those from control (p<0.01). During the continuous storage of peeled fresh walnut, kernel from aPE50 gained the least increase in acid value and peroxide value, showed increase of total phenols and flavonoid in later stage; persistent lower MDA content and lipoxygenase (LOX) activity than control and CO2+pPE50. Therefore, aPE50 was a better mode of modified atmosphere package for fresh walnut preservation than others.