Physical and chemical changes of rapeseed meal proteins during toasting and their effects on in vitro digestibility

Table 4 Proportion (%) of the secondary structures of rapeseed meals toasted for different times^a

Toasting time	Intermolecular β-sheets	Intramolecular β-sheets	α-helix	T2	A2	α-helix : β-sheet
Toasting time	(1,627 – 1,630/cm)^b	(1,634 – 1,635/cm)	(1,655 – 1,656/cm)	(1,674/cm)	(1,692/cm)
0 min	49.0	5.5	30.5	8.9	6.1	0.62
20 min	63.1	nd	16.2	13.7	6.9	0.26
40 min	60.8	nd	17.5	14.4	7.2	0.29
60 min	60.0	nd	18.0	14.6	7.4	0.30
80 min	59.4	nd	18.0	15.0	7.5	0.30
100 min	57.5	nd	20.4	14.6	7.5	0.36
120 min	57.9	nd	19.7	14.7	7.7	0.34
SEM	1.0	-	1.1	0.5	0.1	0.03
P-value
Linear	0.94	-	0.63	0.04	<0.001	0.56
Quadratic	0.06	-	0.04	0.01	0.004	0.03

^a T2 turns, A2 intermolecular hydrogen-bonded β-sheets, nd not detected, SEM standard error of the mean
^bRegions of the Fourier transform infrared spectra

ISSN: 2049-1891