Effect of the desolventizing/toasting process on chemical composition and protein quality of rapeseed meal

Table 4 Effect of processing conditions on the contents of total and individual glucosinolates in rapeseed products (μmol/g defatted dry matter, unless otherwise stated)^a

			Rapeseed meal
Item	RS	RSC I	A	B	C	D	E
Total glucosinolates^b	34	26	15	12	8	6	4
Progoitrin^b	13.4	10.90	6.55	5.01	3.63	2.49	1.72
Gluconapoleiferin^b	1.41	1.33	0.83	0.61	0.42	0.01	0.17
Gluconapin^b	7.50	5.88	3.76	2.89	2.12	1.56	0.91
4-Hydroxyglucobrassicin^b	5.13	3.07	0.98	0.66	0.42	0.24	0.13
Glucobrassicanapin^b	4.85	4.03	2.55	1.92	1.40	1.01	0.49
Glucobrassicin^b	0.37	0.34	0.18	0.16	0.11	0.09	0.02
Gluconasturtiin	0.43	0.17	0.18	0.21	0.22	0.17	0.16
4-Methoxyglucobrassicin^b	0.48	0.63	0.32	0.29	0.16	0.12	0.10
Neoglucobrassicin	0.20	0.08	0.02	0.01	0.01	0.01	n.d.
Degradation rate of total GSL, %^c		22	54	65	75	83	89
Degradation rate of aliphatic GSL, %^cd		18	50	62	72	81	88
Degradation rate of indol GSL, %^cd		33	76	82	89	93	96

RS = rapeseed; RSC I = rapeseed cake one; GSL = glucosinolates; n.d. = not detectable
^aLinear regression analysis refers to the effect of residence time in the desolventizer/toaster on total and individual glucosinolates contents of rapeseed meals A-D. Rapeseed meals A-D represent four differently processed rapeseed meals under standardized and defined conditions in a pilot plant (for details see Table 1)
^bLinear decrease (P < 0.05)
^cIn comparison to defatted rapeseed
^dAliphatic GSL represent the sum of progoitrin, gluconpoleiferin, gluconapin, and glucobrassicanapin; indol GSL that of 4-hydroxyglucobrassicin, glucobrassicin, and neoglucobrassicin

ISSN: 2049-1891