Abdel-Aal El-Sayed M, Rabalski Iwona
Agriculture and Agri-Food Canada, Guelph Research and Development Centre, 93 Stone Road West, Guelph, ON N1G 5C9, Canada.
Antioxidants (Basel). 2022 May 26;11(6):1059. doi: 10.3390/antiox11061059.
Phenolic acids are the major polyphenols in cereal grains and they undergo changes in their composition and structure during processing. This study investigated changes in phenolic acids and antioxidant properties during baking of bread and muffin made from hairless canary seed (HCS), L., alone or in blends with corn and wheat. The changes were monitored after dry mixing, dough/batter formation, and oven baking. Phenolic acids were quantified in products using HPLC and antioxidant activity was based on DPPH, ABTS, and ORAC assays. Eight phenolic acids were primarily present in the bound fraction extracts, while only a few phenolic acids were detected in the free or unbound fraction extracts. Ferulic was the dominant phenolic acid in wheat, corn, and HCS followed by -coumaric acid but the latter was extremely high in HCS compared to wheat and corn. After baking, bound phenolic acids decreased in breads and muffins, while the unbound phenolic acids increased. Dough preparation resulted in about 5-13% reductions in bound ferulic acid in addition to 2-9% after oven baking with a total reduction of about 10-20% subject to bread formulation. On the contrary unbound ferulic acid increased by 48-307% after dough preparation and 138-225% after oven baking with a total increase 273-495%. Similarly, muffin-making process resulted in 26-30% reductions in bound ferulic acid after batter preparation and 4-7% after oven baking with reductions of 34-37% in muffins, while the unbound ferulic acid increased by about 35-105% and 9-29%, respectively, with a total increase 47-116%. The baking process resulted in improved DPPH, ABTS, and ORAC antioxidant activities in breads and muffins despite the initial reductions after dough preparation. In general, baking process resulted in tangible increases in unbound phenolic acids which eventually could improve their bioavailability and bioactivity.
酚酸是谷物中的主要多酚类物质，在加工过程中其组成和结构会发生变化。本研究调查了由无毛金丝雀籽（HCS）单独制成或与玉米和小麦混合制成的面包和松饼烘焙过程中酚酸和抗氧化性能的变化。在干混、面团/面糊形成和烤箱烘焙后监测这些变化。使用高效液相色谱法对产品中的酚酸进行定量，抗氧化活性基于二苯基苦味酰基自由基（DPPH）、2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）和氧自由基吸收能力（ORAC）测定。八种酚酸主要存在于结合态提取物中，而在游离或未结合态提取物中仅检测到少数酚酸。阿魏酸是小麦、玉米和HCS中的主要酚酸，其次是对香豆酸，但与小麦和玉米相比，后者在HCS中的含量极高。烘焙后，面包和松饼中结合态酚酸减少，而未结合态酚酸增加。面团制备导致结合态阿魏酸减少约5 - 13%，烤箱烘焙后再减少2 - 9%，根据面包配方，总量减少约10 - 20%。相反，未结合态阿魏酸在面团制备后增加48 - 307%，烤箱烘焙后增加138 - 225%，总量增加273 - 495%。同样，制作松饼的过程中，面糊制备后结合态阿魏酸减少26 - 30%，烤箱烘焙后减少4 - 7%，松饼中减少34 - 37%，而未结合态阿魏酸分别增加约35 - 105%和9 - 29%，总量增加47 - 116%。尽管面团制备后抗氧化活性最初有所降低，但烘焙过程使面包和松饼中的DPPH、ABTS和ORAC抗氧化活性提高。总体而言，烘焙过程导致未结合态酚酸显著增加，最终可能提高其生物利用度和生物活性。
