Sodium hydroxide enhances extractability and analysis of proanthocyanidins in ensiled sainfoin (onobrychis viciifolia)

Ramsay, A., Drake, C., Grosse Brinkhaus, A., Girard, M., Copani, G., Dohme-Meier, F., Bee, G., Niderkorn, V. and Mueller-Harvey, I. (2015) Sodium hydroxide enhances extractability and analysis of proanthocyanidins in ensiled sainfoin (onobrychis viciifolia). Journal of Agricultural and Food Chemistry, 63 (43). pp. 9471-9479. ISSN 1520-5118 doi: 10.1021/acs.jafc.5b04106

Abstract/Summary

Little information exists on the effects of ensiling on condensed tannins or proanthocyanidins. The acetone–butanol–HCl assay is suitable for measuring proanthocyanidin contents in a wide range of samples, silages included, but provides limited information on proanthocyanidin composition, which is of interest for deciphering the relationships between tannins and their bioactivities in terms of animal nutrition or health. Degradation with benzyl mercaptan (thiolysis) provides information on proanthocyanidin composition, but proanthocyanidins in several sainfoin silages have proved resistant to thiolysis. We now report that a pretreatment step with sodium hydroxide prior to thiolysis was needed to enable their analysis. This alkaline treatment increased their extractability from ensiled sainfoin and facilitated especially the release of larger proanthocyanidins. Ensiling reduced assayable proanthocyanidins by 29%, but the composition of the remaining proanthocyanidins in silage resembled that of the fresh plants.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/46385
Identification Number/DOI	10.1021/acs.jafc.5b04106
Refereed	Yes
Divisions	Life Sciences > School of Agriculture, Policy and Development > Department of Animal Sciences > Animal, Dairy and Food Chain Sciences (ADFCS)- DO NOT USE
Uncontrolled Keywords	silage; thiolysis; unextractable tannins; alkaline pretreatment; reaction products
Publisher	American Chemical Society
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