Changes in the carotenoid content of apricot (Prunus armeniaca, var Bergeron) during enzymatic browning: ?-carotene inhibition of chlorogenic acid degradation
✍ Scribed by de Rigal, David; Gauillard, Fr�d�ric; Richard-Forget, Florence
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 116 KB
- Volume
- 80
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Considering the numerous bene®cial effects in human health ascribed to carotenoids, studies were performed to investigate the modi®cation of carotenoid amount and composition during apricot enzymatic browning. First works on bruised apricot purees have shown a trans-b-carotene isomerisation (20%) induced by enzymatic browning. To clarify this isomerisation, oxidation of chlorogenic acid in presence of trans-b-carotene, catalysed by puri®ed apricot polyphenoloxidase (PPO), was followed by HPLC and polarography. Isomerisation rate of trans-b-carotene in its cis isomer was found to increase with chlorogenic acid concentration. Moreover, trans-b-carotene was shown to be a potent inhibitor of phenol degradation. This inhibition was partially ascribed to PPO inhibition (non-competitive inhibitor towards phenol with an apparent Ki close to 0.5 mM, a mixed type inhibitor towards oxygen with an apparent Ki close to 0.15 mM). The additional inhibition was explained by non-enzymatic reactions involving trans-b-carotene and chlorogenic acid o-quinones and leading to phenol regeneration and carotene isomerisation.