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 O 2 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.

The process of making a dough, allowing time for maturation, dispersing the dough in water and wet sieving/washing to obtain a protein fraction and starch milk was studied using response surface methodology by changing the water to¯our ratio in dough making (400±710 g kg À1 ), maturation time (45±660 s) and the type of¯our. Two grades of bread wheat¯our and durum clear¯our were studied. The effects of aging at ambient temperature for up to 29 days and the addition of ascorbic acid at 100 or 500 mg kg À1¯o ur on separation behaviour were also studied for freshly milled high-grade (65% extraction) bread wheat¯ours at constant maturation time, 600 s, and at optimum farinograph water absorption value. The quantities and dry matter contents of the protein fraction and starch milk were measured; a sample of starch milk was centrifuged to obtain decantate, tailings and prime starch fractions, and the dry matter contents of each were determined. All the dried samples were also analysed for protein content. The fractional recoveries of dry matter and protein in the protein fraction, prime starch, tailings and decantate were calculated for each experiment. The acid values of our oils were also determined on some aged¯our samples. The results indicated superior separation characteristics in high-grade wheat¯our compared with lower-grade¯ours. The water to¯our ratio was more in¯uential than maturation time within the range studied. Contrary to the initial expectation, no statistically signi®cant effect of¯our aging was observed in the studies with no additive, and ascorbic acid addition was not found to improve the wet separation behaviour, the separation behaviour becoming even worse at the 100 mg kg À1 level. Acid value showed a slight increase with time.

No abstract

No abstract

No abstract