QUALITY CHANGES OF ONIONS (ALLIUM-CEPA L) DURING STORAGE .2. WEIGHT LOSSES

In stores with out-door air ventilation and mechanical cooling intact outer dry scales which were fully developed admitted only minor weight losses of onions from transpiration and respiration. Split outer scales, however, increased weight losses by as much as 50 to 90%. Naked onions produced 70 to 190% higher losses, and pinholing by Agrotis segetum Schiff. increased losses even by 120 to 150% compared with undamaged onions. Losses depended also on the onion size (+42 and 57% resp. for the smallest grading, -10.5 and -0.8% for the largest as compared to the medium-sized fraction). Rot infection caused weight losses which were two to three times higher than those from sprouting. The respiration intensity after out-door air ventilation differed between 14.4 and 19.8 W . t-1 irrespectively of cropping year, place and variety. The respiration rate was clearly increased by storage temperatures, sprouting (+32%), nakedness (+106%) and rot (+226%).