Date of Award

1982

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

Pressed alfalfa juice at pH 8.5 was heated (60(DEGREES)C) and centrifuged to produce a brown solution. This solution was further heated (80(DEGREES)C) at pH 4.0, centrifuged, and freeze-dried to produce a light tan powder. Tetrahymena pyriformis W. was used to test quality of cytoplasmic and chloroplastic fractions of alfalfa leaf protein concentrate (ALPC). Chloroplastic ALPC supported poor cell growth, probably because of high concentrations of chlorophyll, fat, and chlorogenic acid to which Tetrahymena is reported to be sensitive. Data indicated that isoleucine, phenylalanine, threonine and sulfur-containing amino acids in cytoplasmic ALPC were higher than those in soybean. Data indicated cytoplasmic ALPC to be higher quality protein than soy, and approached casein in biological value. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) alfalfa juice protein contained 7 protein subunits. After coagulation and freeze-drying, there were six protein bands present. Extraction treatment affected the lower molecular weight subunits, in that after extraction, they could no longer be detected or characterized. Two subunits were nearly constant in proportion and molecular weight during processing, perhaps reflecting the theory that some water-soluble proteins contain small numbers of hydrophobic groups, which contribute resistance to denaturation. Coagulated and freeze-dried protein contained new protein subunits, which had not appeared in alfalfa juice protein. The presence of this subunit after extraction may have been caused by the presence of chromogenic proteins extractable only under specific conditions. Ground beef containing 4 and 15% soy and 4 and 15% leaf protein were sensory evaluated. Panelists differentiated between the samples when compared to pure beef. Pure beef samples had the highest acceptability, followed by samples with 4 and 15% soy protein. Samples extended with 15% soy protein were rated about equal to those with 4% alfalfa LPC samples. Ground beef with 15% ALPC was less desirable than any other treatment, implying limited potential for this type of ALPC as an extender in meat products.

Pages

94

Share

COinS