Premium
Effect of alkali on the refunctionalization of soy protein by hydrothermal cooking
Author(s) -
Wang H.,
Wang T.,
Johnson L. A.
Publication year - 2005
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-005-1092-3
Subject(s) - alkali metal , soy protein , chemistry , meal , food science , organic chemistry
The effects of hydrothermal cooking (HTC) at alkaline conditions on refunctionalization of heat‐denatured protein of extruded‐expelled (EE) soy meals and on preparation of soy protein isolate (SPI) from EE soy meal were determined. Two HTC setups, flashing‐out HTC (without holding period) and HTC with holding for 42 s at 154°C, were evaluated. Alkali (NaOH) addition dramatically enhanced the refunctionalization of EE meal having an initial protein dispersibility index of 35. The more alkali added, the more refunctionalization occurred. Extensive refunctionalization was achieved at 0.6 mmol alkali/g EE meal, and additional improvement was small with more alkali. For both HTC setups, the solids and protein yields of SPI from alkali‐HTC‐treated EE meals were significantly higher than those from HTC without alkali addition. The yield of protein as SPI increased from 40 to 82% after HTC treatment at 0.6 mmol alkali/g EE meal compared with no alkali addition. The emulsification capacities of SPI after alkali‐HTC were similar to those from HTC without alkali. SPI from holding‐tube HTC‐treated EE meals had higher emulsification capacities than those prepared by flashing‐out HTC.