Suitability of five different potato cultivars (Solanum tuberosum L.) to be processed as fresh-cut products

摘要

Five different potato cultivars ('Agata', 'Agria', 'Almera', Marabel' and 'Vivaldi') were cut and stored at two temperatures (5 and 20pC) for 9d in order to investigate their browning potential and their suitability to be processed as fresh-cut product on the basis of their initial quality attributes such as color, water content, polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities, total phenolics, ascorbic acid contents, sugar composition and antioxidant activity (AOX). In addition, color changes and general appearance were monitored during storage. ANOVA results showed that the five cultivars were characterized by different initial color and yellow intensity with b* decreasing significantly from 'Marabel' (30.6), to 'Agria' (28.0), 'Almera' (21.6), 'Vivaldi' (19.6), and 'Agata' (16.5). Initial composition varied widely among cultivars and accounted for the different post-cutting performances. 'Marabel' and 'Agata' potatoes showed least color changes among the five cultivars, and scored the maximum for appearance when stored at 5pC, while 'Marabel' received the highest score also when stored at 20pC. 'Marabel' showed a relatively low phenol content (32.5mg GE/100g fw), low PPO activity (10.02U/g fw), one of the highest antioxidant activities (18.02mg TE/100g fw) and the highest soluble sugar content (2.3g/100g fw). 'Vivaldi' and 'Agria' cultivars showed an intermediate potential in terms of storability and appearance, while 'Almera' was the less suitable cultivar to be used as fresh-cut, despite its high content in ascorbic acid (34.8mg/100g fw) and high antioxidant activity (23.2mg TE/100g fw), also showing one of the highest phenol content (46.1mg GE/100g fw) and PPO activity (14.7U/g fw). A principal component analysis on the chemical and physical attributes showed a high correlation between phenol content, PAL and PPO activity, a* value, and hue angle variation at 5 and 20pC. Appearance score, and fructose and glucose contents were positively correlated with each other and inversely correlated with hue angle variation. Score, and fructose and glucose contents allowed discrimination between 'Marabel' and the other varieties. 'Marabel' and 'Agata' potatoes were represented by the negative portion of Principal Component 2, while 'Almera', 'Agata', and 'Agria' were located on the positive axis, highly correlated with hue angle variation which was statistically higher for these varieties.