Durum wheat bran by-products: Oil and phenolic acids to be valorized by industrial symbiosis

Wheat bran represents one of the main by-products of debranning/milling of wheat and is currently used for animal feeding. To evaluate other possibilities of by- product valorization, the lipid matter and phenols in five different fractions of durum wheat bran by-products obtained from debranning and milling are determined during storage. The lipid content (3.6%–6.3%) significantly changes in the different by-products, showing an increasing content of free fatty acids (FFA) during 30-day storage, which corresponded to a consistent decrease in triacylglycerols (TAG). The lipid matter is mainly composed of polyunsaturated fatty acids (57.20% ± 0.36%–59.43% ± 0.72% of total fatty acids), of which linoleic acid is the most representative, but it significantly decreases during storage. The detected free acidity level confirms lipase activity during storage, since the highest value (65.3%) is reached after 30-day of storage. Total phenolic content of durum wheat bran by-products does not significantly change during storage, nor does single phenolic acids in the soluble conjugated and insoluble bound fractions (except for caffeic acid). These results suggest that high value nutritional compounds can be extracted from durum wheat bran by-products before being supplied for animal feeding, but as requested in food chains, the presence of contaminants should be excluded.