DESTRUCTION OF POTATO PEEL TRYPSIN INHIBITOR BY PEELING AND EXTRUSION COOKING

Potato peels, a by-product of potato processing, can serve as a source of concentrated dietary fiber, but potato trypsin inhibitors (TI) in peels could reduce nutritional quality. Peels prepared by two methods (abrasion or steam) were extruded at 110C or 150C with feed moistures of either 30% or 35%. Prior to extrusion, abrasion and steam peels contained 45.57 and 8.06 TIU/g, respectively. Extrusion reduced TI activity by 75–85% in abrasion peels, but no reductions were observed for steam peels. TI may not pose a nutritional problem for steam peels with or without extrusion. Abrasion peels should be extruded, or processed by another thermal method, prior to use in foods.     

Effects of Elevated CO2 Atmosphere on Storage of Freshwater Crayfish (Pacifastacus leniusculus)

The effects of elevated CO₂ levels on the keeping quality of cooked, freshwater crayfish was investigated. Experiments were conducted using an enriched atmosphere of 80% CO₂:20% air compared to air storage at 4°C. Chemical and microbial changes were correlated with sensory panel evaluations of flavor, odor and texture. After 28 days of storage, the concentrations of ammonia and trimethylamine and total plate counts were lower in crayfish stored under carbon dioxide as compared to samples stored in air. The sensory panel found no significant difference between the odors of the samples stored in CO₂ atmosphere for 21 days and fresh cooked crayfish, whereas samples stored in air were found to have significantly more fishy flavor and odor after 14 days of storage.     

Emulsion Stability as Affected by Competitive Adsorption Between an Oil-Soluble Emulsifier and Milk Proteins at the Interface

The effect of an oil-soluble emulsifier upon adsorption properties of β-casein and β-lactoglobulin at the oil-water interface was studied. Addition of emulsifier improved the emulsification properties, but lowered emulsion stability. Higher concentrations decreased emulsification capacity, due to an increase in oil phase viscosity, and interfered with several protein assays, except the o-phthaldialdehyde (OPA) assay. Depletion measurements revealed that the emulsifier displaced β-casein more readily than β-lactoglobulin from the surface of droplets, which correlated with emulsification and stability measurements. Displacement of proteins was not complete due to emulsifier-induced formation of a multiple w-o-w emulsion, which accounted for the missing protein in the continuous phase.     

Rates of Heating and lnstron Measurements for Turkey Batters with Sodium Salts of Nitrite, Chloride and Phosphate

Electrical resistance heating at two voltage levels was used to heat muscle batters containing a variety of sodium salts. Peak heights or depths from Instron curves indicated resistance of heated muscle batters to expansion or contraction. Batters heated at the higher voltage had increased peak heights, higher temperatures at which the batters reached that peak and decreased peak depths. Batters with sodium nitrite became less fluid in the initial stages of heating and expanded more with heating than those with water only. Sodium chloride increased peak heights and increased the temperatures at which the batters reached those peaks. Batters with sodium chloride and sodium tripolyphosphate were the least fluid during heating and began to expand at the lowest temperatures.     

Elimination of the development of bitter flavour in Cheddar cheese made from milk containing heat-denatured whey protein

A method has been developed for increasing the yield of Cheddar cheese by as much as 7.5% by the incorporation of denatured whey protein in curd. The process effectively eliminates the development of intense bitter off-flavours which are generally associated with the production of cheese from acidified milk. Although the manufacturing procedure produces cheese with acceptable Cheddar flavour, the development of high quality Cheddar flavour is impaired