New Method for Evaluating Astringency in Red Wine

Abstract

Astringency is an important sensory attribute of red wine. It is usually estimated by tasting and is subject to a certain subjectivity. It can also be estimated by using the gelatin index. This procedure is not very reproducible because there are many gelatins on the market with a heterogeneous composition. Furthermore, the gelatin index determines procyanidin concentration by acid hydrolysis that gives only an approximate result. This paper proposes a new and reproducible method that determines astringency by using ovalbumin as the precipitation agent and tannic acid solutions as standards. Statistical analysis of the results indicates that this method is more reproducible (RSD = 5%) than the gelatin index (RSD = 12%) and correlates better with sensorial analysis.

Modulating polyphenolic composition and organoleptic properties of apple juices by manipulating the pressing conditions

“…Oxidised procyanidins have tested as more reactive with proteins (Le Bourvellec et al, 2004b), and therefore presumably more astringent (Llaudy et al, 2004), than the native molecules. However, oxidation also increases the reactivity with cell walls (Le Bourvellec, Guyot, & Renard, 2009), so that the balance in the juice is uncertain.…”

Assay of Antioxidant Capacity and Phenolic Compounds in some Romanian and Cypriot Wine

“…Therefore, they contribute to the anticarcinogenic, antiatherogenic, antiinflammatory, antimicrobial, and antioxidant activities of some fruits (Llaudy et al, 2004;Chang et al, 2012;Xu et al, 2012).…”

Sensory assessment and chemical measurement of astringency of Greek wines: Correlations with analytical polyphenolic composition

“…It can also be estimated chemically by various methods, which are based on tannin precipitation. A reproducible method was developed which used ovalbumin as precipitation agent and tannic acid solutions as standards (Llaudy et al, 2004). Recently, Mercurioo and Smith (2008), compared a polysaccharide-based (methylcellulose) and a proteinbased (Bovine Serum Albumin-BSA) tannin assay for their ability to precipitate tannins.…”