Survey of the Variation in Grape Marc Condensed Tannin Composition and Concentration and Analysis of Key Compositional Factors.
Grape marc contains a number of compounds with potential antimethanogenic activity in ruminants, including condensed tannins (CTs). Using direct phloroglucinolysis, a survey of CT chemistry across 66 grape marc samples showed diversity in concentration (6.9 to 138.8 g/kg of dry matter). Concentration was found to be independent of CT composition, although all compositional variables were significantly correlated (P < 0.0001). Twenty samples diverse in CT were selected from a cluster analysis and analyzed for compounds relevant to ruminant digestion and methanogenesis, including metabolizable energy (6.6-12.0 MJ/kg DM), crude protein (3.2-14.4% DM), neutral detergent fiber (18.4-61.4% DM), and ethanol soluble carbohydrates (2.0-40.6% DM). Fatty acid concentrations varied throughout the 20 samples (5.2-184.5 g/kg DM), although fatty acid profile showed two distinct groups. Grape marc varies widely in nutritional value, and in compounds that have been linked with changes in ruminant digestion and methane emissions.
The Australian Wine Research Institute , P.O. Box 197, Glen Osmond, Adelaide 5064, Australia.
Josh L
JL
Hixson
Department of Economic Development, Jobs, Transport, and Resources , 1301 Hazeldean Road, Ellinbank, Victoria 3821, Australia.
Joe L
JL
Jacobs
The Australian Wine Research Institute , P.O. Box 197, Glen Osmond, Adelaide 5064, Australia.
Eric N
EN
Wilkes
The Australian Wine Research Institute , P.O. Box 197, Glen Osmond, Adelaide 5064, Australia.
Paul A
PA
Smith
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D004032:Diet / Q000662:veterinary; D004043:Dietary Fiber / Q000032:analysis; D004063:Digestion; D005227:Fatty Acids / Q000032:analysis; D005419:Flavonoids / Q000032:analysis; D005504:Food Analysis; D008697:Methane / Q000737:chemistry; D009753:Nutritive Value; D025341:Principal Component Analysis; D044945:Proanthocyanidins / Q000032:analysis*; D012417:Rumen / Q000378:metabolism; D027843:Vitis / Q000737:chemistry* / Q000145:classification*
D004043:Dietary Fiber; D005227:Fatty Acids; D005419:Flavonoids; D044945:Proanthocyanidins; C404987:flavan-3-ol; D008697:Methane
condensed tannin; grape marc; methanogenesis; phloroglucinolysis; proanthocyanidin; processing; variation