M. Bouraoui et al., IN-SITU INVESTIGATION OF PROTEIN-STRUCTURE IN PACIFIC WHITING SURIMI AND GELS USING RAMAN-SPECTROSCOPY, Food research international, 30(1), 1997, pp. 65-72
Raman spectroscopy was used to study the in situ protein structure in
raw and salted surimi from Pacific whiting, and in gels formed by sett
ing (32 degrees C), cooking (86 degrees C) or setting followed by cook
ing. The set-cooked gel had a better gel strength and fold score than
the gels which were only set or cooked. Large increases in relative in
tensity of a band near 530 cm(-1) in the cooked and set-cooked gels in
dicated changes in disulfide bond stretching or aliphatic chain vibrat
ions. Involvement of hydrophobic interactions of aliphatic chains in s
alting, setting and cooking was inferred from the decreased intensity
of a band near 2930 cm(-1) assigned to C-H stretching vibrations. Chan
ges in a doublet near 850 and 830 cm(-1) suggested an increasing invol
vement of tyrosine residues as hydrogen bond donors in a non-polar env
ironment after setting or setting-cooking, in contrast to increasing e
xposure to a polar environment in gels formed by cooking alone. Second
ary structure estimation based on the amide I band indicated a change
from predominantly alpha-helical structure in raw surimi to higher ant
iparallel beta-sheet and lower alpha-helical contents after setting an
d particularly during the kamaboko stage. (C) 1997 Published by Elsevi
er Science Ltd on behalf of the Canadian Institute of Food Science and
Technology.