Alkylresorcinols in U.S. and Canadian wheats and flours.

Field: Agricultural and Biological Sciences (Life Sciences)

Cereal Chem. 67(5):413-417 Wheat samples from the United States and Canada and flours from Linear regression analysis between protein and alkylresorcinol content those wheats were analyzed for alkylresorcinols. Alkylresorcinols in wheats indicated that they are negatively correlated. Wheat type had no effect ranged from 317.5 to 655.0 ,4g/g dry weight. Flours contained very small on flour alkylresorcinol content. Patent percentage of flours was shown amounts of alkylresorcinols and the values ranged from 0.025 to 14.45 to be positively correlated with the amount of alkylresorcinols. Both kernel )ug/g dry weight. Generally, hard wheats had higher protein and lower maturity and cereal types influenced the amount of alkylresorcinols. As alkylresorcinols; soft wheat had lower protein and higher alkylresorcinols. maturity increased, alkylresorcinol content decreased. A group of compounds known to inhibit growth in several animal species has been isolated from cereal grains (Wieringa 1967, Evans et al 1973, Pawlik 1979, Sedlet et al 1984) and identified as resorcinol derivatives with hydrocarbon chains at the fifth position. Cereal alkylresorcinols were found to be mixtures of saturated, monoenoic, and dienoic homologs with 13-29 carbon side chains (Wieringa 1967; Kozubek 1984b, 1987a; Seitz and Love 1987). The C21, C23, C25, C27, and C29 homologs were observed in rye oil (Briggs 1974). In wheat bran, the C25 and C27 components were found to be predominant (Wenkert et al 1964). Wieringa (1967) states that factors such as soil type, fertilization, and weather may influence the content of alkylresorcinols. Cereal grains grown under the same agronomic and climatic conditions during consecutive crop years showed only slight variations from year to year. However, Verdeal and Lorenz (1977) found that alkylresorcinol content decreases in rye and triticale as the grains mature. Alkylresorcinols are present quite early in kernel development, and the apparent decrease in proportion of alkylresorcinols may be a dilution effect, partly due to deposition of starch and protein in developing grain kernels. By milling wheat, rye, and triticale into bran, shorts, and flour fractions, and subsequent analysis, Verdeal and Lorenz (1977) and Salek (1978) showed the bran to contain the highest alkylresorcinol level. Intermediate values were found in the shorts, whereas the flour fractions produced relatively low values. This indicates that a gradient exists with the highest amounts of the compounds in the pericarp, intermediate amounts in the aleurone layer, and relatively small but detectable amounts in the endosperm portion of cereal grain kernels. Seitz and Love (1987) suggested that analyses of alkylresorcinols in milling fractions could be a useful measure of bran contamination in flours. Generally, the amount of alkylresorcinols in cereals is highest in rye, lower in wheat and triticale, and very low in other cereals such as oats, barley, and corn (Verdeal and Lorenz 1977, Musehold 1978, Kozubek and Demel 1980). However, some varieties of wheat have an alkylresorcinol content similar to that of rye. Selection of cultivar progeny was effective in increasing or decreasing alkylresorcinol content (Evans et al 1973). Thus far, these compounds have only been suspected to be detrimental factors in animal nutrition, although concern has occasionally been raised about possible ill-effects on humans in European countries with high rye bread consumption (Anonymous 1974). There are no established human toxicity levels for these compounds. In model studies, alkylresorcinols were shown to cause red blood cell hemolysis, permeability changes of erythrocytes and liposomes to small solutes, and DNA strand scission, and to be involved in many pathological conditions (Kozubek 1984a, 1987b; Kozubek and Demel 1980; Kozubek et al 1988).