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Grading

The onion bulbs are classified into three grades based on bulb size i.e. A (> 80 mm), B (50-80 mm) and C (30-50 mm) grades. In India, grading of onion is usually performed manually either before storage or before marketing.  It is a cumbersome process and requires many labourers. The grading with machine reduces labour charges and also increases precision. DOGR has developed manual and motorized grading machines for grading of onion bulbs (Fig. 8). Onion bulbs can be classified into five categories with grading machine based on the bulb size. The efficiency of manual operated grading machine is five times of the manual grading while the efficiency is almost 20 times with motorized grading machine. The accuracy of grading of onion with grading machine is around 90% as against 70% with manual grading.