No abstract

SUMMARY: The carbonyl compounds in cooked turkey and chicken skin fractions after storage were isolated as their 2,4‐dinitrophenylhdrazones. The monocarbonyl class was separated into methyl ketones, 2‐enals and 2,4‐dienals and measured spectrophotometrically. The turkey skin residue fraction contained higher concentrations of carbonyls than did the chicken samples. The oil extract from the skin of both groups was similar in carbonyl concentration. Lower storage temperature dramatically lowered the development of carbonyls. Phospholipid phosphorus determinations indicated the residue contained high levels of polar lipid; whereas, negligible amounts were in the oil. Thin‐layer chromatography of the carbonyl classes from the skin residue indicated mainly C7‐C9 2‐enals and C8, C9 2, 4‐dienals in the unsaturated aldehyde fractions. Changes in fatty acid composition of the residue polar lipids during storage suggested linoleic and arachidonic acids as the probable substrates in autoxidative deterioration.

Egg-white was concentrated by vacuum evaporation (VE) and reverse osmosis (RO). The treatments consisted of a control, RO process, VE process using 50°C water-jacket temperature and 60-min processing time (5060VE), and a VE process using 60°C water-jacket temperature and ds-minute processingiime (604S&). Solids c&tents for ihe concentrates were 17.82% for the RO. 17.41% for the 6045VE. and 18.98% for 506OVE. The VE product had better foaming prop&ties and comparable gel qualities to that of the RO product. Foam enhancing and stabilizing additives improved the quality of all concentrates. Electrophoretic studies indicated a significant decrease in globulins Al and A2 in the VE treatments.been compared (Froning et al., 1987). Solids increased from an initial 11% to 23% in both systems. The concentrated eggwhite was spray-dried, and 0.1% sodium lauryl sulfate was added for functional tests. Neither UF nor RO significantly affected angel food cake volumes, and electrophoresis indicated no changes in protein fractions. Shear stress of gels made from the concentrates increased as concentration increased; however, shear strain was not affected by concentration.Our specific objectives were to compare the effects of reverse osmosis (RO) and vacuum evaporation (VIZ) on the chemical and physical properties of egg white, and to determine the effects of food additiv& on the functional properties of concentrates produced by RO and VE.

Suitable methods to process full-fat flour from dried winged bean seeds, their effect on trypsin-inhibitor activity and keeping qualities of the flour were studied. Soaking in 0.5% or 1% sodium bicarbonate solution and boiling for 30 -45 min was found to be a suitable process for hull removal. Dry dehulling methods resulted in only 14 -22% hull separation, while wet processing treatments were not effective. Soaking the winged bean seeds (12 hr) in 0.5% sodium bicarbonate, sodium carbonate and sodium chloride solutions reduced 30 -40% of the trypsin inhibitor activity. Winged bean full-fat flour could be stored for 4 wk under ambient conditions.

Liquid egg-white was evaporated under vacuum (4.7 kPa) in a waterjacketed vessel to produce a concentrated, liquid egg white product. Three water-jacket temperatures (40,SO and 60°C) and four processing times (0, 30, 45 and 60 min) were used. For the 6O"C, 60-min treatment, solids content increased (~~0.05) from 11.5% to 21.8%. Concentration did not affect (20.05) true gel strain but gel shear stress increased (~~0.05) with increased solids concentration.