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作者 Awika, Joseph Mobutu
書名 Antioxidant properties of sorghum
國際標準書號 0496358765
book jacket
說明 118 p
附註 Source: Dissertation Abstracts International, Volume: 64-04, Section: B, page: 1563
Chair: Lloyd W. Rooney
Thesis (Ph.D.)--Texas A&M University, 2003
Sorghum varieties grown in Texas between 1998 and 2002, as well as processed sorghum products, were analyzed for antioxidant potential using three methods; oxygen radical absorbance capacity (ORAL), 2,2'-azinobis (3-ethyl-benzothiaziline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). Phenolic antioxidants from these samples were separated and characterized by HPLC. Two extraction solvents, 1% HCl in methanol (Me-HCl), and 70% aqueous acetone (Ac-aq), were compared. The Me-HCl generally extracted sorghum antioxidants better than Ac-aq. This effect was more significant in black sorghums than brown sorghums
The ORAC activities (Trolox equivalents, TE) among black and brown sorghum brans were high (1,000--3,100 pmol TE/g) compared to common fruits and vegetables (80--900 mumol TE/g). Retention of antioxidant activity after processing was 57--78% for baked, and 70--100% for extruded sorghum products relative to raw samples. Antioxidant values by the ORAC method were 2--3 times higher than ABTS or DPPH values for the sorghums. However, the three methods correlated highly with one another (R 2 > 0.95). The ABTS method was overall the most suitable for sorghums
Brown sorghum grains and brans had high procyanidin contents (21--58 mg/g) compared to blueberry (20 mg/g), as measured by HPLC. Polymers with DP > 10 were the major procyanidin constituents (66--84%) of brown sorghums. The relative ratio of oligomers (DP < 10) to polymers (DP > 10) increased significantly in processed products
Black sorghum brans had high anthocyanin content (4.5--11.0 mg/g) compared to commercial sources (0.8--10.0 mg/g). Luteolimdin and apigeninidin were the major anthocyanins in the black sorghums, accounting for about 50% of total anthocyanins. The red sorghum bran had high levels of naringenin (1.0 mg/g) compared to the other sorghum brans (0.17--0.26 mg/g)
Specialty sorghums are a rich source of different phenols with high antioxidant potential and are a commercially viable source of these compounds for foods or pharmacological applications. High retention of antioxidant activity in processed products implies the sorghums are valuable food ingredients
School code: 0803
Host Item Dissertation Abstracts International 64-04B
主題 Agriculture, Food Science and Technology
Alt Author Texas A&M University
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