空调控温对小麦粮堆空气特性及品质的研究

Study on the Effects of Air Conditioning Temperature Control on Air Characteristics and Quality of Wheat Grain Bulk

研究空调对小麦高大平房仓控温过夏的效果及评价指标,选用鲁粮集团某库19仓,在小麦入仓后第二、三年过夏期间将空调设定在25℃,与对照17号仓比较,粮堆表层、二层、三层及四层分别降低3.4、2、1.5及1.35℃,含湿量、相对湿度(RH)及湿球温度对表层粮食和整个粮堆分别降低3.85和1.5 g/kg、3.55%和3.85%、3.65℃和2.2℃。DSC测定的两个仓粮堆热特性参数没有显著差异。与17号仓比较,19号仓小麦RVA测定的糊化峰值粘度、衰减值、最终粘度略降低;全麦粉馒头质构特性参数如硬度、黏着性、弹性、咀嚼性略降低。主成分分析确定了糊化结束温度及峰高度、糊化温度及峰值时间、质构参数如硬度及咀嚼性均是评价小麦控温过夏储藏的优选指标。扫描电镜分析表明,与17号仓比较,19仓中小麦籽粒横截面要致密,微孔均匀;纵截面大淀粉颗粒之间的小淀粉粒少一些。结果表明:小麦高大平房仓夏季开启空调有助于降低粮堆干球温度及籽粒间隙空气特性参数,延缓储粮害虫生长发育,保持小麦籽粒微观结构,延缓品质劣变。

This study investigated the effects and evaluation indicators of air conditioning temperature control for summer storage of wheat in large flat storage silos.In the second and third years after wheat was stored in Silo No.19 of Luliang Jituan Pingyuan Grain Storage Depot,the air conditioning was set to 25℃,and the conditions were compared with those in the control Silo No.17.The temperatures at the surface,second layer,third layer,and fourth layer of the grain bulk were reduced by 3.4℃,2℃,1.5℃,and 1.35℃,respectively.The moisture content,relative humidity(RH),and wet-bulb temperature were reduced by 3.85 g/kg and 1.5 g/kg,3.55% and 3.85%,and 3.65℃ and 2.2℃for the surface grain and the entire grain bulk,respectively.No significant differences were observed in the thermal characteristic parameters of the grain bulks in the two silos.Compared with Silo No.17,the peak viscosity,breakdown,and final viscosity of wheat in Silo No.19 slightly decreased,and the texture parameters,such as hardness,adhesiveness,springiness,gumminess,and chewiness,also slightly decreased.Principal component analysis identified the gelatinization end temperature and peak height measured by DSC,the gelatinization temperature and peak time measured by RVA,and texture parameters such as hardness,gumminess,and chewiness as preferred indicators for evaluating the summer storage of wheat under temperature control.In-depth scanning electron microscopy analysis revealed that the cross-sections of wheat kernels in Silo No.19 were more compact with uniformly distributed micropores,and the longitudinal sections had fewer small starch granules between large starch granules compared to those in Silo No.17.The results indicated that operating air conditioning in large flat storage silos during summer helped reduce the dry-bulb temperature of the grain bulk and the air characteristics in the interstitial space between kernels.It also slowed the growth and development of storage pests,and maintained the microstructure of wheat kernels,which could delay quality deterioration.