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Structure, Protein Interactions and In Vitro Protease Accessibility of Extruded and Pressurized Full‐Fat Soybean Flakes
Author(s) -
Jung Stephanie,
Mahfuz Abdullah,
Maurer Devin
Publication year - 2009
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/s11746-009-1371-x
Subject(s) - extrusion , chemistry , protease , extraction (chemistry) , hydrolysis , cotyledon , chromatography , size exclusion chromatography , soybean proteins , biochemistry , soybean oil , enzyme , biophysics , soy protein , materials science , botany , biology , metallurgy
The objectives of the present study were to determine how extrusion (barrel temperature of 100 °C) and high‐pressure processing (HPP, 200 and 500 MPa, 15 min, 25 °C) of full‐fat soybean flakes (FFSF) modified the structure of soybean cotyledon cells, the protein interactions and the in vitro protease accessibility. Cellular disruption of the cotyledon cells was only observed for extruded FFSF. Extrusion and HPP at 500 MPa favored formation of insoluble protein aggregates, in which oil was entrapped. High pressure size exclusion chromatography (HPSEC) and extraction methods using buffers containing SDS and 2‐mercaptoethanol suggested that noncovalent interactions were the main forces in protein aggregate formation during HPP 500 MPa and extrusion. Intermolecular cross‐linking by disulfide bonding was also involved in insoluble aggregates, but at a lesser extent than noncovalent interactions. Extrusion and HPP 500‐MPa treatment enhanced the proteolytic attack, while treatment at 200 MPa had no impact. Drastic changes in the peptide profile of the extracted proteins were, however, only observed for the enzyme‐treated 500‐MPa FFSF. Optimal oil and protein extraction yields required cellular disruption of cotyledon cells and hydrolysis of protein aggregates, which were obtained with enzyme‐assisted aqueous extraction of extruded FFSF.