Premium
KINETICS OF AVAILABLE LYSINE LOSSES IN A SOY PROTEIN ISOLATE: CONFIRMATION OF THE ‘TRANSITION PHASE’ BY PROTEIN EFFICIENCY RATIO TESTS
Author(s) -
WOLF J. c.,
THOMPSON D. R.,
Ahn P. C.,
HEGARTY P. V. J.
Publication year - 1979
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1979.tb10067.x
Subject(s) - lysine , sugar , chemistry , soy protein , chromatography , transition (genetics) , food science , biochemistry , amino acid , gene
Available lysine losses in soy protein isolates during thermal processing go through three phases: a fist‐order loss, a transition phase and a no‐loss phase. The transition phase shows a statistically significant (P < 0.02) increase in available lysine when measured by the fluoro‐dinitrobenzene (FDNB) method. Using the protein efficiency ratio method (PER), a statistically significant (P < 0.1) increase in available lysine was demonstrated in samples processed at 80° C for 700 mm. The PER values decreased from 2.65 ± 0.04 to 1.17 ± 0.04 after 600 min of processing. At 700 min the PER value increased to 1.37 ± 0.05. At 80°C the transition phase in systems containing 4% sugar occurs 600 mm after processing is initiated according to previously published equations. The PER and FDNB results exhibited an excellent correlation (r = 0.98). Thus, PER results confirm the increase detected using the FDNB procedure.