Effect of Mechanical Grading on Fruit Quality during Low Temperature Storage in Early Wase of Satsuma Mandarin (Citrus unshiu Marc.)

Changes in fruit quality of early-season satsuma mandarin were investigated after ripening procedure and packing house operation such as washing, wax coating, and heat drying. Compulsory dry after wax coating in the mechanical grading system promoted fruit quality deterioration even under low temperature condition. The rate of respiration 4 days after the storage, averaging 2μL․kg^-^1․h^-^1, was lower than that of start of the examination. In pre-graded fruits, incidence of decay increased after 10 days of the storage. In contrast, decay was low at 0.3% level after 17 days of storage when fruits had not been pre-graded in mechanical grading system. The results indicate that forced heat drying should be avoided after waxing. Function of a sorting machine should be improved to reduce drop impact during the grading procedure. Cold chain system may alleviate post-storage loss of pre-graded early-season satsuma mandarin fruit.