Use of a spouted bed to improve the storage stability of wheat germ followed in paper and polyethlyene packages

Stabilization of wheat germ by heating in a spouted bed for 180–540 s with air at 140–200 °C was studied. The lipase activity decreased by 6–65%. Wheat germ processed at 200 °C for 360 s was ranked highest in sensory evaluation, described as having ‘a golden color’ and ‘nutty flavor’, and its lipoxygenase activity had decreased by 91.2%. This product and raw wheat germ were stored in paper, polyethylene and vacuum‐packed polyethylene pouches at 5 °C, room temperature (18–26 °C) and 40 °C, and the moisture contents, water activities, free fatty acid contents and peroxide values were followed for 20 weeks. The increases were faster in paper pouches than in the polyethylene ones; vacuum packaging in polyethylene did not bring about significant improvement. The peroxide values of raw samples exceeded 10 meq O2 kg−1 oil after 3–23 days while those of the processed samples stored at room temperature or 5 °C were still less than 10 after 20 weeks. The free fatty acid content and peroxide value changes were expressed by zero order kinetics, resulting in similar activation energies for the raw and processed samples