Effects of processing on availability of total plant sterols, steryl ferulates and steryl glycosides from wheat and rye bran.
Rye and wheat bran are excellent natural sources of plant sterols in the diet. Their content, however, may vary according to processing. Thermal (roasting and heating in a microwave oven), mechanical (milling and cryogenic grinding), and enzymatic treatments (hydrolysis with xylanase or beta-glucanase or a mixture of these two enzymes) were performed, and their effect on sterol content, extractability of sterols and the characteristic steryl conjugates of cereals (steryl ferulates, steryl glycosides, and acylated steryl glycosides) were studied. Mechanical and enzymatic treatments increased the apparent sterol content, whereas aqueous processing without enzymes hindered the availability of total sterols, especially from rye bran. Changes were also seen in the amounts of steryl conjugates caused by the enzymatic treatments. On the basis of the results of this study, it can be speculated that a combination of fine particle size and enzymatic processing results in optimal sterol availability in cereal processing.
Nyström
Laura
L
Department of Applied Chemistry and Microbiology, University of Helsinki, P.O. Box 27, Latokartanonkaari 11, FI-00014 Helsinki, Finland. laura.nystrom@helsinki.fi
Lampi
Anna-Maija
AM
Rita
Hannu
H
Aura
Anna-Marja
AM
Oksman-Caldentey
Kirsi-Marja
KM
Piironen
Vieno
V
D000215:Acylation; D001682:Biological Availability; D003373:Coumaric Acids / Q000032:analysis*; D004043:Dietary Fiber / Q000032:analysis*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D005511:Food Handling / Q000379:methods*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006027:Glycosides / Q000032:analysis*; D006358:Hot Temperature; D006868:Hydrolysis; D010840:Phytosterols / Q000032:analysis* / Q000302:isolation & purification; D012434:Secale / Q000737:chemistry*
D003373:Coumaric Acids; D004043:Dietary Fiber; D006027:Glycosides; D010840:Phytosterols; C004999:ferulic acid; D006026:Glycoside Hydrolases; D043364:Endo-1,4-beta Xylanases