Abstract: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.