Bitterness and astringency of flavan-3-ol monomers, dimers and trimers

Abstract

Intensity of astringency and bitterness of seven flavonoid compounds was evaluated by a time‐intensity (TI) procedure. Eighteen trained judges rated intensity continuously from ingestion, through expectoration at 10 s until extinction of the sensation. The seven stimuli included two flavan‐3‐ol monomers, (+)‐catechin and (−)‐epicatechin, three dimers and two trimers synthesised from catechin or epicatechin by condensation with (+)‐dihydroquercitin. As the degree of polymerisation increased, maximum bitterness intensity (Imax) and total duration (Ttot) decreased whereas astringency Imax increased. The monomers were significantly higher in bitterness at Imax than the dimers, which were significantly higher than the trimers. Astringency Imax of the monomers was lower than the dimers or trimers, although no significant difference was found in Ttot among the polymer classes. The bond linking the monomeric units had an influence on both sensory properties. The catechin‐catechin dimer linked by a 4→6 bond was more bitter than both catechin‐(4→8)‐catechin and catechin‐(4→8)‐epicatechin. Astringency was affected by both the specific linkage and the identity of the monomeric units with the dimer, catechin‐(4→8)‐catechin, being lower in astringency than either catechin‐(4→6)‐catechin or catechin‐(4→8)‐epicatechin. © 1999 Society of Chemical Industry

Expression Analysis of the ANR and LAR Gene in Fragaria × ananassa cv. Toyonaka

“…In recent years, more and more attention has been drawn to PAs and their monomers because of their beneficial effects on human health, such as the activities of immunomodulatory and anticancer (Zhao et al, 2007), antioxidant (Rao et al, 2004), Anti-inflammatory (Subarnas et al, 2000) and antithrombotic effects (Sano et al, 2005). Besides, PAs also provide the flavors of bitterness and astringency to beverages, especially the wines, where they have a significant influence on the mouth feel and the color alternation of the products (Lee et al, 2008;Peleg et al, 1999;Fei et al, 2009). …”

Genotype, Environment and Management Practices on Red/ Dark-Colored Fruits Phenolic Composition and Its Impact on Sensory Attributes and Potential Health Benefits

“…Polymer size afects astringency correlating positively with the perception of astringency [84]. Increased galloylation can be responsible for increased "abrasiveness" while trihydroxylation of the B-ring can decrease it [85]. As referred by He et al [86], the synthesis of astringent substances controlled by a variety of structural and regulatory genes must be studied.…”

Effect of polyphenol oxidase (PPO) and air treatments on total phenol and tannin content of cocoa nibs

“…A study of astringency and bitterness of flavan-3-ol monomers, dimers and trimers revealed that molecular size was the major factor influencing the sensory properties of these attributes. As molecular size increased, bitterness decreased and astringency increased [9]. The use of PPO without air also contributed to reduction of astringency and bitterness in cocoa nibs, and improved the acceptance of a chocolate formulated with treated cocoa [3].…”