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Effects of Processing on Availability of Total Plant Sterols, Steryl Ferulates and Steryl Glycosides from Wheat and Rye Bran

Nystrom, L., Lampi, A.M., Rita, H., Aura, A.M., Oksman-Caldentey, K.M., Piironen, V.
Journal of agricultural and food chemistry 2007 v.55 no.22 pp. 9059-9065
food processing, food processing quality, nutrient availability, phytosterols, ferulic acid, glycosides, wheat bran, rye bran, heat treatment, milling, grinding, enzymatic treatment, particle size, nutrient content, nutritive value, food analysis, food composition
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 β-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.