Proteins extracted from defatted oats were chemically modified by acylation (succinylation and acetylation), potassium linoleate treatment or partial hydrolysis with trypsin. Total essential amino acid content was slightly lowered by acetylation, but unaffected by succinylation. Gel filtration chromatography showed some dissociation of oat polypeptides by succinylation, while trypsin hydrolysis caused considerable breakdown of the protein. Solubility and emulsifying properties were significantly improved by all the modifications. Fat binding capacity was improved by acylation and linoleate treatment, while water hydration capacity and foaming properties were improved by trypsin and linoleate modifications. The gelling property was improved by acylation. When meat protein was substituted with oat protein in model wieners, there was a decrease in cook yield, cohesiveness and firmness. However, when compared to the unmodified oat protein, succinylation led to an improvement in performance in an emulsified meat system.

No abstract

When the pH of cottage cheese whey was adjusted to 4.5 in the presence of 6.7 mM FeCls, @lactoglobulin was eliminated from the whey as a precipitate. However, the majority of immunoglobuhns were also coprecipitated. To recover immunoglobulins together with ol-lactalbumin, the whey pH was adjusted to 3.0 in the presence of 4.0 mM Feels. After centrifugation of the whey, the supernatant contained exclusively @-lactoglobulin; other whey proteins were found in the precipitate. Excess Fe +++ in the precipitate was removed by ion exchange or by ultrafiltration. This protein concentrate had a protein composition much more similar to that of human milk whey than that of ultrafiltered whey protein concentrate.

No abstract

Mechanical properties of wiener batters substituted with vital wheat gluten (VWG) or acid-solubilized (deamidated) VWG were studied. Substitution led to decreased storage (G') and loss (G") moduli. Cooking profiles showed initial modulus decreases due to fat melting, with G' reaching minimum around 50-5X, followed by rapid increases. Sharp G" and tan 6 transitions appeared near 48°C. Substitution caused upward shift in transition temperatures, and at 20%, decreased moduli. Substitution caused no significant (p < 0.05) decreases in cook yield or texture. Microscopical examination revealed random binding of gluten to meat protein, forming continuous networks. Batters containing deamidated gluten had structure similar to all-meat or VWGsubstituted batters.