ESTIMATION OF THE LOSSES CAUSED BY MITES IN WHEAT DURING STORAGE

Abstract

In the present study, investigations were made to find the changes in different physical and chemical parameters of three wheat varieties (Lasani-08, Faisalabad-08 and Sehar-06) infested by varying levels of stored grain mites (Rhizoglyphus tritici). Results showed that significant variations were observed in physico-chemical characteristics, mineral profile, amino acid profile and fatty acid profile of three wheat varieties. Mite population was significantly increased and reaches upto 7513 mites in Lasani-08 after six months in the treatment initially treated with twenty pairs of mite. Maximum decrease in the thousand kernel weight was observed in Lasani-08 out of all the three varieties after six months of storage which was from 38.50g in control to 26.07g in treatment with maximum number of mites. Wet and dry gluten were also found decreasing with increasing infestation of stored grain mites in three wheat varieties. Wet gluten ranged from 22.65% in T3 after six months to 31.74% in T4 after one month in Sehar-06, while dry gluten ranged from 6.17% in T3 after six months to 9.92% in T4 after one month in Sehar-06. Moisture content was found increasing with increasing mite population after different storage periods in three varieties. Maximum moisture was observed in Lasain-08 after six months of storage in the treatment initially treated with twenty pairs of mites that was 18.13%. Crude protein and crude fat were found decreasing in three varieties and ranged from 10.03% after six months in T3 of Faisalabad-08 to 14.43% after one month in T4 of Sehar-06 and 0.52% after six months in T3 of Faisalabad-08 to 1.38% after one month in T4 of Faisalabad-08, respectively. Fiber and ash content showed a significant and positive correlation with mite population. Fiber ranged from 1.03% after one month in T4 of Lasani-08 to 4.30% after six months in T3 of Sehar-06. Ash ranged from 1.23% after three and six months in T4 of Lasani-08 to 3.60% after six months in T3 of Sehar-06. Maximum decrease in NFE of Sehar-06 was observed after six months in the treatment having maximum mite population (T3) that was 62.12% from 65.64% in control. Flour quality parameters such as falling number, water absorption, dough development time, dough stability, mixing tolerance index and softening of dough showed significant and negative correlation with mite population. Iron (Fe), Manganese (Mn), Copper (Cu), Calcium (Ca), Potassium (K), Sodium (Na), Magnesium (Mg) and Zinc (Zn) in different wheat varieties were found increasing with increasing mite population after one, three and six months of storage, although this increase was just a proportion increase due to the depletion of other contents in grains. Different amino acids were found decreasing with increasing mite population in three wheat varieties after different storage periods and exhibited negative correlation with mite population. Different fatty acids were found decreasing with increasing mites infestation. After different storage periods Capric, Myristic, Palmitic and Palmitoleic ranged from 0.05 to 0.18%, 0.07 to 0.19%, 12.25 to 16.25% and 0.15 to 0.40%, respectively while Stearic, Oleic, Linoleic and Linolenic ranged from 0.21 to 0.62%, 12.15 to 15.90%, 55.33 to 59.82% and 4.80 to 7.50%, respectively under different treatments. Conclusively, it can be inferred that stored grain mites infestation deteriorate the quality of stored wheat.