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Physicochemical properties of soya bean protein gel prepared by microbial transglutaminase in the presence of okara
Author(s) -
Yan Wang,
Kun Yu,
Yang Xu,
Li Guo,
Xianfeng Du
Publication year - 2015
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/ijfs.12906
Subject(s) - particle size , confocal laser scanning microscopy , tissue transglutaminase , rheology , chemistry , soy protein , fourier transform infrared spectroscopy , dynamic mechanical analysis , particle (ecology) , emulsion , protein isolate , food science , materials science , chemical engineering , composite material , polymer , biochemistry , biophysics , enzyme , organic chemistry , oceanography , geology , engineering , biology
Summary The influences of okara on the gelling and secondary protein structure of soya protein isolate ( SPI ) were investigated. Okara was ultra‐refined by high‐pressure homogenisation. The resulting particle sizes and microscopic morphologies were determined using a laser particle size analyser and a confocal laser scanning microscope, respectively. After okara homogenisation, surface area average particle size (D 32 ) decreased from 49.68 to 23.29 μm and volume average particle size (D 43 ) decreased from 118.94 to 55.08 μm. Dynamic rheological measurements showed that the storage ( G ′) and loss ( G ′′) moduli of SPI gelled in the presence of okara were mostly higher than those of SPI gels alone and were increased as the okara amounts increased. Linear law analysis revealed that SPI –okara gels were weak gels and frequency independent. Fourier transform infrared spectroscopy showed that okara and transglutaminase influenced the prevalence of α‐helices, β‐turns, β‐sheet and random coils.