Extraction, Bioactivity, and Stability of Wheat Bran Alkylresorcinols

Whole grain intake may be linked to a lowered risk of chronic diseases and such positive effects might be attributed to phenolic lipids, alkylresorcinols (ARs), found in cereal bran. This study aimed to characterize ARs in wheat bran (WB), investigate the influence of environmental factors on AR composition, measure AR bioactivity including antioxidant activity (AA) and investigate AR stability during baking. Moreover, the prebiotic potential of WB-soluble dietary fibre (SDF) was explored using yogurt models. Specific objectives were achieved by the following projects. The effects of cultivar, and region on the ARs content in 24 wheat cultivars grown in Ontario were studied, by GC-MS and their AA were evaluated. TPC (3.0 to 58.0 mg FAE/g), DPPH (5 to 68%), ORAC (6.0 to 94.0 µmol TE/g) and ARs (21.0 to 1522.0 μg/g) of WB extracts were significantly affected by location and cultivar (P < 0.05). The stability of WB-ARs was studied using different bread formulations. Bread ARs (1.1 to 82.9 mg/100 g) were heat stable during baking at 255 °C for 12 min. A positive correlation was observed between TPC and ORAC (R2 = 0.90). Two extraction methods were used to compare the AR contents of WB. The % ARs per extract using acetone versus SC-CO2 extraction of both WB samples studied were in the range of 10.9% -15.6% and 5.1% - 6.6%, respectively. The prebiotic potential of WB-SDF to enhance lactic acid bacteria (LAB) survival in yogurt models was explored. Total DF (53%) was counted as a sum of SDF (6%) and IDF (47%). HPLC analysis of DF fractions treated with alkaline hydrolysis showed that IDF (84.2%) had a higher phenolic acid (PA) content than SDF (15.8%). There was a significant difference in total bacterial count (9.1 log CFU/mL), pH (4.8) and TTA (1.4%) in yogurt samples containing 4% WB compared to controls during the four week cold storage period (4 °C). These results could lead to practical applications of WB-ARs and SDF in the functional foods and nutraceutical industry. Furthermore, increased WB utilization will reduce Agri-Food leftovers, thus improving environmental sustainability.