| الوصف: |
Consumption of freshly-cut horticultural products has increased in the last few years. The principal restraint to using freshly-cut carambola is its susceptibility to tissue-browning, due to polyphenol oxidase-mediated oxidation of phenolic compounds present in the tissue. The current study investigated the susceptibility to browning of star fruit slices (Averrhoa carambola L.) of seven genotypes (Hart, Golden Star, Taen-ma, Nota-10, Malásia, Arkin, and Fwang Tung). Cultivar susceptibility to browning as measured by luminosity (L*) varied significantly among genotypes. Without catechol 0.05 M, little changes occurred on cut surface of any cultivars during 6 hour at 25°C, 67% RH. Addition of catechol led to rapid browning, which was more intense in cvs. Taen-ma, Fwang Tung, and Golden Star, with reduction in L* value of 28.60%, 27.68%, and 23.29%, respectively. Browning was more intense in the center of the slices, particularly when treated with catechol, indicating highest polyphenol oxidase (PPO) concentration. Epidermal browning, even in absence of catechol, is a limitation to visual acceptability and indicates a necessity for its control during carambola processing. Care must be given to appropriate selection of cultivars for fresh-cut processing, since cultivar varied in browning susceptibility in the presence of catechol. ; O consumo de produtos hortícolas minimamente processados tem aumentado nos últimos anos. Entretanto, a principal restrição para o uso de carambolas minimamente processadas é sua susceptibilidade ao escurecimento devido a oxidação de compostos fenólicos presentes nos tecidos que é mediado pela polifenoloxidase (PPO). Investigou-se a suscetibilidade ao escurecimento de fatias de carambola (Averrhoa carambola L.) de sete cultivares (Hart, Golden Star, Taen-ma, Nota-10, Malásia, Arkin e Fwang Tung). A suscetibilidade das cultivares ao escurecimento, medido através da luminosidade (L*), variou significativamente entre cultivares. Sem a aplicação do catecol (0,05 M), ocorreram poucas mudanças ... |