title: Hydrogenolytic depolymerization of procyanidin polymers from hi-tannin sorghum bran.
abstract: Depolymerization of procyanidin polymers into oligomers enhances their bioavailability and bioactivity because oligomers are bioavailable. Hydrogenolysis was applied in this study to depolymerize hi-tannin sorghum bran procyanidin polymers into oligomers. The yield and composition of oligomers under different hydrogenolysis conditions was investigated. Results showed that raising temperature from 50 to 100 °C significantly increased total yield of oligomers. Higher temperatures (150 and 200 °C) produced monomers with lower yield. The highest yield of oligomers (38.8%) was obtained using 1 MPa hydrogen whereas 3 MPa hydrogen in reaction vessel decreased yield. Total yield of oligomers reached the highest at 1-3 h and then decreased with prolonged reaction time. Yield increased with palladium-on-carbon (Pd/C, a catalyst) amount from 0.5 to 3 mg and plateaued with Pd/C amount from 3 to 10 mg. The maximum yield of produced oligomers was achieved under 100 °C, 1 MPa hydrogen pressure, 1-3 h, and 3-10 mg Pd/C.
authors.affiliation: Food Science and Human Nutrition Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Agricultural and Biological Engineering Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Jijiao
authors.initials: J
authors.lastname: Zeng
authors.affiliation: Agricultural and Biological Engineering Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Tong
authors.affiliation: Food Science and Human Nutrition Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, United States; School of Food Science and Technology, Jiangnan University, Jiangsu 214122, China.
authors.forename: Yajing
authors.initials: Y
authors.lastname: Qi
authors.affiliation: Food Science and Human Nutrition Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, United States. Electronic address: LGu@ufl.edu.
authors.forename: Liwei
authors.initials: L
authors.lastname: Gu
mesh_terms: D044946:Biflavonoids / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D002392:Catechin / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004043:Dietary Fiber / Q000032:analysis*; D006358:Hot Temperature; D058105:Polymerization; D044945:Proanthocyanidins / Q000737:chemistry*; D045868:Sorghum / Q000737:chemistry*; D013634:Tannins / Q000032:analysis*
chemical_list: D044946:Biflavonoids; D001704:Biopolymers; D004043:Dietary Fiber; D044945:Proanthocyanidins; D013634:Tannins; C017674:procyanidin; D002392:Catechin
keywords: Catechin; Depolymerization; Epicatechin; Hydrogenolysis; Procyanidins