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ARS Home » Southeast Area » Little Rock, Arkansas » Arkansas Children's Nutrition Center » Research » Publications at this Location » Publication #213663
Title: Extrusion Increased Bioavailability of Sorghum Procyanidins in Weanling Pigs

Author
item GU, LIWEI - ACNC/UAMS
item HOUSE, SUZANNE - ACNC
item Prior, Ronald
item ROONEY, LLOYD - TEXAS A&M UNIVERSITY

Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2007
Publication Date: 4/28/2007
Citation: Gu, L., House, S.E., Prior, R.L., Rooney, L. 2007. Extrusion increased bioavailability of sorghum procyanidins in weanling pigs [abstract]. The FASEB Journal. 21(6):A120.

Interpretive Summary: Sorghum is the fifth most important cereal crop in the world after wheat, rice, corn, and barley. More than 35% of the sorghum is grown directly for human consumption. The United States is the largest producer and exporter of sorghum, accounting for 20% of world production and almost 80% of world sorghum exports during 2001–2002. Tannin sorghum contain high level of unique antioxidant polyphenols—procyanidins. Procyanidins are beneficial for health, but its absorptions are low. Food process that can improve the absorption of procyanidins may enhance the health promoting effects of sorghum. Sorghums are often extruded to render high digestibility of proteins and starches. We found extrusion decreased the total procyanidins in sorghum. However, extrusion increased the procyanidins of lower molecular size and thus increased the absorption of procyanidins. This discovery indicated that extruded sorghum is a better source of antioxidant and may be a more effective in preventing diseases. Such finding is of great importance to both food technology and nutrition sciences.

Technical Abstract: Procyanidins are beneficial for human health; however, the bioavailability of procyanidins is low. The effect of food processing on procyanidin bioavailability has not been studied. Sumac sorghum (50% grain + 50% bran) contains 36 mg/g of total procyanidins with monomers, dimers, and polymers being 0.08, 0.6, 26.4 mg/g, respectively. Extrusion decreased the total and polymeric procyanidins to 22 and 14 mg/g, respectively, while increasing monomers and dimers to 0.12 and 1.0 mg/g. Six weanling pigs (8.9+/-1.1 kg) received a single dose by gavage of sorghum (7 g/kg0.75 ), sorghum extrudate, or white sorghum (50% grain + 50% bran) in a randomized crossover design. Treatments were separated by a 7-day washout period. Blood was drawn at 0, 1, 2, and 4 hour. Serum (+/-)-catechin, 3'-O-methylcatechin, 4'-O-methylcatechin, epicatechin, 3'-O-methylepicatechin, 4'-O-methylepicatechin peaked at 1 hr and were 18, 43, 1, 0.7, 0.7, 0.3 nmol/L for pigs receiving sorghum, respectively. Serum levels in pigs receiving extruded sorghum were 66, 110, 2, 16, 8, 11 nmol/L, respectively. Serum levels of (+/-)-catechin, 3'-O-methylcatechin, and the total catechins were higher in pigs fed extruded sorghum at 1, 2, and 4 hour post dose (p' 0.05). The majority of the absorbed catechins were excreted within four hours after feeding. Urinary excretion of total catechins was significantly higher in pigs fed extruded sorghum than those fed unextruded sorghum. Procyanidin dimers were not detected in serum or urine. The levels of catechins were close to zero in serum and urine of pigs fed white sorghum. In conclusion, extrusion improved the bioavailability of procyanidins in sorghum due in part to depolymerization of polymers and increased digestibility of starch and proteins.