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ARS Home » Southeast Area » Little Rock, Arkansas » Microbiome and Metabolism Research Unit » Research » Publications at this Location » Publication #223981
Title: Sorghum Extrusion Increases Bioavailability of Catechins in Weanling Pigs

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

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2008
Publication Date: 2/6/2008
Citation: Gu, L., House, S., Rooney, L.W., Prior, R.L. 2008. Sorghum extrusion increases bioavailability of catechins in weanling pigs. Journal of Agricultural and Food Chemistry. 56(4):1283-1288.

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 contains high level of unique antioxidant polyphenols—procyanidins. Procyanidins are beneficial for health, but their 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 more effective in preventing diseases. Such finding is of great importance to both food technology and nutrition sciences.

Technical Abstract: Catechins and procyanidins are beneficial for human health; however, their bioavailability is low. The effect of food processing on catechin bioavailability from sources containing predominantly procyanidins has not been studied. The sumac sorghum mixture (50% whole grain + 50% bran) used in this study contained catechins, procyanidins dimers, and polymers at 0.08, 0.6, and 26.4 mg/g, respectively. Extrusion decreased the polymeric procyanidins by 48% to 22 mg/g while increasing catechins (50%) and dimers (64%) to 0.12 and 1.0 mg/g, respectively. Six weanling pigs (8.9 plus/equal to 1.1 kg) received a single dose by gavage of the sorghum mixture (7 g/kg0.75), the sorghum mixture extrudate, or white sorghum (50% whole 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 h. Plasma catechin, 3'-O-methylcatechin, 4'-O-methylcatechin, epicatechin, 3'-O-methylepicatechin, and 4'-O-methylepicatechin peaked at 1 h and were 18, 43, 1, 0.7, 0.7, and 0.3 nmol/L for pigs receiving sorghum, respectively. Plasma levels in pigs receiving extruded sorghum were 66, 110, 2, 16, 8, and 11 nmol/L, respectively. Plasma levels of catechin, 3'-O-methylcatechin, and the total catechins were higher in pigs fed extruded sorghum at 1, 2, and 4 h postdose (P less than/equal to 0.05). The majority of the absorbed catechins were excreted within 4 h after feeding. Urinary excretion of total catechins was significantly higher in pigs fed extruded sorghum than in those fed nonextruded sorghum. Procyanidin dimers were not detected in plasma or urine. The levels of catechins were close to zero in plasma and urine of pigs fed white sorghum. In conclusion, extrusion improved the bioavailability of catechins in sorghum.