Changes in oil‐type sunflowerseed stored at 20 C at three moisture levels

Oil‐type hybrid sunflowerseed held at 63%, 83% and 93% relative humidities (RH) at 20 C attained equilibrium moisture contents (mc) of 6.7 ± 0.1%, 9.8 ± 0.1% and 13.4 ± 0.3%, respectively, and were stored under these conditions for up to 60 weeks (wk). Germinability was inversely related to both storage duration and RH. Initially, the seed contained only field fungi (mainlyAlternaria spp. andPhoma macdonaldii) and 0.5% free fatty acids (FFA). At 6.7% mc, the amount ofAlternaria spp. andP. macdonaldii isolated declined slowly with time, storage fungi did not invade the seed, and FFA in extracted oil did not change significantly during 60 wk storage. No significant correlation was found between FFA, germination, mold count (cfu/g) or fungi recovered. At 9.8% mc, field fungi declined more rapidly than at 6.7% mc, storage fungi (mainlyEurotium rubrum andE. repens) were isolated from the seed after 4 wk, and FFA increased to 2.5% after 40 wk. FFA content was negatively correlated with germination (r=−0.91) and withAlternaria alternata (r=−0.90) but was positively correlated withE. rubrum (r=0.78). At 13.4% mc, field fungi vanished and storage fungi invaded the seed more rapidly than at 9.8% mc, and FFA increased to 6.3% after 24 wk storage. FFA content was positively correlated with storage fungi such asAspergillus versicolor (r=0.74) and negatively correlated with germination (r=−0.88) andA. alternata (r=−0.82). After 14 wk storage the fungus recovered most frequently wasA. versicolor, followed byEurotium rubrum, E. repens, A. alternata, E. amstelodami, Penicillium spp. andMalbranchea sulphurea.