Influence of storage conditions on the formation of aldehydes during barley and malt aging

The changes of oxidation aldehydes of lipid,Strecker aldehydes and furfural of barley and malt Gairdner,during storage at 10 and 35℃,were investigated by solid phase micro-extraction(SPME) combined with GCMS. Comparing with fresh barley,Strecker aldehydes and furfural of fresh malt were higher,while contents of oxidation aldehydes of lipid and enzyme activity of lipoxygenase were lower. As both furfural and oxidation aldehydes of barley and malt increased distinguishedly,they are promising indicator to be used to evaluate fresh degree of barley and malt. After five months storage at 10℃ and 35℃,comparing to fresh counterpart,trans-2-noneal concentration of barley increased 1.01 and 1.62 times,while trans-2-noneal concentration of malt increased 5.12 and 17.74 times,respectively. Taking its high flavor activity into account,trans-2-noneal was considered to be the most potential indicator to evaluate barley and malt quality and freshness degree.Based on aldehydes data in this paper,it verified the fact again that the importance effect of lower storage temperature to the freshness degree of barley and malt.