The treatment of rapeseed meal and its effect on chemical composition and egg tainting potential

Abstract

Treatment of high glucosinolate Brassica nupus meals with lime, ammonia or by micronisation lowered their tainting potential by reducing their progoitrin, soluble tannin and sinapine contents. These effects were not sufficient to prevent inhibition of trimethylamine oxidation and the consequent rise in egg trimethylamine levels above the tainting threshold when the meals were fed to susceptible hens as sources of protein (100 g kg-' diets).

Nutritional and physiological effects of rapeseed meal sinapine in broiler chickens and its metabolism in the digestive tract

“…33 Although absorption of SNP cannot be ruled out by this study, the fact that apparent digestibility is higher in faeces than ileal contents and the presence of SA in ileal and faecal samples from the SNP bisulphate trihydrate treatments (no SA in the diet) support the concept that SNP is hydrolysed from the ester bond to form SA and choline by gut micro-organisms. Again this is in agreement with research on fishy flavour in chicken eggs.…”

“…28 The fact that TMA is produced from choline derived from SNP in both the small intestine and caeca is also indirect evidence of the potential of bacteria to modify SA to a different form. 33,34 The only study conducted on the metabolism of SA in rats demonstrated that several metabolites derived from SA were found in the urine. 35 Direct studies on other simple phenolic acids (caffeic, coumaric) in rats disclosed substantial modification of phenolic acid to other phenolic metabolites by gut bacteria.…”

A method for the decrease of phenolic content in commercial canola meal using an enzyme preparation secreted by the white-rot fungusTrametes versicolor

“…One of the possible solutions is an enzymatic process, Fenwick et al (1984) using mild reaction conditions, which could considerably reduce the operating costs and decrease the risk of degradation of valuable food components during processing. It has already been shown that the polyphenol oxidase preparation secreted by the white-rot fungus, Trametes versicolor, transforms sinapic acid and its derivatives, including sinapine, in a model enzymatic system (Lacki and Duvnjak, 1996a, 1996c, 1997.…”

“…SIN is directly responsible for a production of the tainted eggs and, therefore, the rations for poultry can contain no more than 0.1% of this compound (Fenwick et al, 1984;Goh et al, 1979). Consequently, the amount of CM included in poultry diets should not exceed 5%, or the meal must be pretreated before it can become a sole source of nutrients.…”

Rapeseed meal‐Glucosinolates and their antinutritional effects Part 6. Taint in end‐products

“…Earlier quoted works [27,28,33,35,46, 731 indicate that dietary progoitrin levels of 0.31 -7.8 pM/g are sufficient to raise TMA levels in eggs so as to cause taint. Assuming that progoitrin constitutes 60% of the glucosinolates in European high glucosinolate N 00 Table 4 Fishy odour and trimethylamine (TMA) content of eggs produced by brown-shelled egg layers fed diets containing extract from various rapeseed cultivars (according to GOH et al rapeseed this means that a diet containing 10% high glucosinolates meal (5 pM/g defatted dry meal) will cause taint.…”