Estimation of nutritional losses caused by Rhizoglyphus tritici (ACARI: Acaridae) in stored wheat

The stored grain mites which are one of the important pests of stored grains can modify the chemical composition of the stored wheat. The change in quality of wheat grains in terms of physical characteristics (thousand kernel weight, moisture, wet and dry gluten), chemical characteristics (crude protein, crude fat, fiber, ash and starch) and flour quality tests (falling number and dough rheological characteristics) of wheat variety Lasani-08 when infested by varying levels of mite infestation for six months were observed under laboratory conditions. Maximum moisture contents (18.13%) were observed in grains having highest number of mites (7513), while minimum moisture contents (16.40%) were found in the grains without mites. Thousand kernel weight, wet gluten, dry gluten, crude protein, fat and starch contents were found minimum in the treatments having maximum number of mite population that was 26.07g, 23.33%, 7.13%, 10.07%, 0.72% and 64.14% respectively as compared to control which was 38.50g, 30.47%, 9.20%, 13.85%, 1.28% and 66.17% after six months of storage. The fiber contents increased significantly in highly infested grains (3.47%) as compared in control (1.07%). The ash contents increased in the infested grains, which was from 1.23% in control to 3.47% in the treatment initially treated with 20 pairs of mites. Falling number, water absorption, dough development time, dough stability, mixing tolerance index and softening of dough was also decreased to 428.33 sec, 56.03%, 3.27 min, 4.30 min, 49.67 BU and 76.67 BU, respectively in the highly infested grains as compared to control which was 651.67 sec, 60.73%, 5.13 min, 6.03 min, 67.67 BU and 141.67 BU, respectively. The results will help to determine the nutritional changes in mite infested wheat during storage.