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Macromolecular changes associated with the heat treatment of soya isolate
Author(s) -
SHEARD P. R.,
FELLOWS A.,
LEDWARD D. A.,
MITCHELL J. R.
Publication year - 1986
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1986.tb01929.x
Subject(s) - chemistry , denaturation (fissile materials) , sodium , water content , hydrophobic effect , chromatography , sodium caseinate , macromolecule , food science , biochemistry , organic chemistry , nuclear chemistry , geotechnical engineering , engineering
The denaturation temperatures of both the 7S and 11S proteins present in a 70 PDI soya flour and an isolate prepared from it, increased by over 30°C as the water content of the system decreased from 90 to 20%. In dilute dispersions (> 70% water), the precipitate formed on heat treatment was almost totally soluble in 3.0% sodium dodecyl sulphate (SDS), irrespective of the heating temperature (20‐120°C). However, in more concentrated systems, heat treatment at 120°C for 1 hr caused increasing amounts of SDS insoluble protein to form as the water content decreased. Such aggregates were also insoluble in beta‐mercaptoethanol (ME), but soluble in mixtures of SDS plus ME. It is suggested that at low concentrations, heat treated soya proteins are primarily aggregated by hydrophobic interactions but that, on decreasing the water content of the system, disulphide bond formation becomes a significant factor in stabilizing the aggregate.