Differences between the Japanese Persimmon (Diospyros kaki Thunb.) 'Denkuro' and 'Hiratanenashi' on Acetaldehyde Production by Their Flesh Discs.

Abstract

Comparison in acetaldehyde production by flesh discs was made to elucidate cultivar diffrences between 'Denkuro' and 'Hiratanenashi' persiommons with respect to the ease of removing their astringency. Soaking of flesh discs of immature astringent fruits in buffer containing ethanol caused more acetaldehyde production in 'Hiratanenashi' than in 'Denkuro'. When 4-methylpyrazole, an alcohol dehydrogenase inhibitor, was added to the same buffer, acetaldehyde production was partly inhibited in 'Hiratanenashi' discs, but not in those of 'Denkuro'. The addition of pyruvate or malate to the buffer increased acetaldehyde production in both cultivars, but at the same substrate level, discs of 'Denkuro' produced more acetaldehyde than did those of 'Hiratanenashi'; higher concentrations of pyruvate or malate tended to inhibit the reaction. The results indicate that 'Hiratanenashi' converts ethanol to acetaldehyde more efficiently than does 'Denkuro', whereas ' Denkuro' metabolizes pyruvate more readily to acetaldehyde than does 'Hiratanenashi'.

Remoção de adstringência de caqui: um enfoque bioquímico, fisiológico e tecnológico

“…Existem cultivares que apresentam maior eficiência no processo de destanização com atmosfera anaeróbica, como a 'Denkro' (TAIRA et al, 1994), outras apresentam maior facilidade de remoção da adstringência com aplicação de vapor de álcool etílico, enquanto outras cultivares não apresentam diferenças, como é o caso da Rama Forte (VITTI et al, 2006). Acredita-se que o motivo dessa diferença esteja na atividade das enzimas piruvato descarboxilase e álcool dehidrogenase.…”