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United States Department of Agriculture

Agricultural Research Service

Research Project: HEALTH PROMOTING FOODS: ENZYMATIC MODIFIED CEREALS AND THEIR CARBOHYDRATES Title: Antioxidant activity and phenolic content of air-classified corn bran

Authors
item Inglett, George
item Chen, Diejun

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 4, 2010
Publication Date: February 16, 2011
Citation: Inglett, G.E., Chen, D. 2011. Antioxidant activity and phenolic content of air- classified corn bran. Cereal Chemistry. 88(1):36-40.

Interpretive Summary: The air-classification procedure has been successfully used for many grain products to obtain the potential nutraceutical ingredients. Corn bran is an excellent source of antioxidant activities and dietary fiber. Information is limited on total phenolic compounds and antioxidant activity for air-classified corn bran. Therefore, this research was conducted to explore the extraction technology for antioxidant compounds and characterization of air-classified corn bran fractions that could have significant impact on their health benefits. The free phenolic contents and antioxidant activities decreased significantly with the increasing particle sizes for all methods used in the study. Also, the oil, protein and ash contents were noticeably decreased with increasing particle sizes. By contrast, bound phenolic content and antioxidant activities increased with increasing particle sizes. Free phenolic contents were much lower than that of bound phenolic contents for the same fraction. Recently, the determination of total antioxidant activities has gained a growing interest as a tool for exploring the putative role of antioxidant-rich products in the prevention of degenerative disease.

Technical Abstract: The effectiveness of extracting free and bound phenolic compounds and antioxidant activities from air classified corn bran was evaluated by various extracting methods. The free phenolic contents and antioxidant activities decreased significantly with the increasing particle sizes for all methods used in the study. Also, the oil, protein and ash contents were noticeably decreased with increasing particle sizes. By contrast, bound phenolic content and antioxidant activities increased with increasing particle sizes. Free phenolic contents were much lower than that of bound phenolic contents for the same fraction. The free antioxidant activities were similar to bound antioxidant activities for the same fraction. It suggests that some phenolic compounds may not exhibit antioxidant activity, and some antioxidant activities were not extractable or degraded during alkaline extraction. Considerable higher free antioxidant activities were found in both direct and double extractions when compared to the single neutral extraction using samples smaller than 30 µm. Similar free antioxidant activities were observed for directed extraction and double extraction. For corn bran fractions, the direct method may be suitable for free phenolic content and antioxidant activity, while the sequential method may be proper for bound phenolic content and antioxidant activity.

Last Modified: 12/22/2014