Sorghum extrusion increases bioavailability of catechins in weanling pigs.

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+/-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<or=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.