储粮中CO2气体的扩散特性及霉菌活动监测研究

将一定量高水分粮食作为模拟霉变点,按照试验的需要埋设在模拟储藏粮堆内,研究霉菌生长产生CO2气体在粮堆中的扩散特性,探索利用气体扩散规律监测储粮霉菌活动的可能性.结果表明:CO2气体可在粮堆中快速扩散,高温能进一步提高扩散速率,30℃比15℃试验组扩散400 mm的速率高58％；霉变发生部位的CO2气体浓度显著高于相隔一定距离检测点的CO2浓度(P＜0.05),但两点间不同浓度CO2气体的扩散比值没有显著差异(P＞0.05)；在敞口储藏状态下,粮堆表面CO2气体散失量较大,检测靠近粮堆表层的CO2气体浓度难以准确反映粮堆的霉菌活动状况.CO2气体在粮堆水平方向的扩散具有向底部沉降的特性,可重点在粮堆的中、下层设置气体检测点,以便灵敏、可靠地监测储粮霉菌的危害.

STUDY ON DIFFUSION CHARACTERISTICS OF CARBON DIOXIDE AND MONITORING OF MOULD ACTIVITY IN STORED GRAIN

Embedding a certain amount of high-moisture grain in simulated grain bulk as simulated mouldy points according to test requirement,we studied the diffusion characteristics of carbon dioxide generated by the growth of mould,and studied the possibility of monitoring the mould activities according to the diffusion rule of carbon dioxide.The results showed that carbon dioxide could diffuse rapidly in the grain bulk,and higher temperature could further improve the diffusion rate,for example,the diffusion rate of carbon dioxide of a test group diffusing 400 mm at 30 ℃ was 58% higher than that at 15 ℃.The concentration of carbon dioxide at the mouldy point was significantly higher than that at a test point away from the mouldy point(p<0.05),but the diffusion ratios of carbon dioxide at the two points had no significant difference(p>0.05).For open storage,the carbon dioxide had large loss amount at the grain surface,so that it was difficult to accurately reflect the mould activity condition of the grain bulk by detecting the concentration of carbon dioxide near the surface layer of grain bulk.Carbon dioxide tended to diffuse to the bottom of the grain bulk in the horizontal direction of the grain bulk,so that gas detection points could be set at the middle layer and the lower layer of the grain bulk to sensitively and reliably detect mould in stored grain.