Effects of Anti-browning Treatments on the Polyphenol Oxidase and Antioxidant Activity of Fresh-Cut Potatoes by Using Response Surface Methodology

Abstract

Fresh-cut potatoes are a good option for consumers who want a healthy diet but have limited time to prepare meals. However, the polyphenol oxidase enzyme released during cutting of potatoes reacts with phenolic compounds, causing browning. Cold storage can slow down this reaction to some extent, but it cannot prevent it. Enzymatic browning lowers polyphenol content and reduces consumer appreciation of freshly cut potatoes stored in the refrigerator for later preparation of a meal. For this reason, studies to minimise negative changes in fresh-cut potatoes during cold storage are important. The quality of freshly cut potatoes immersed in ascorbic acid and collagen hydrolysate solutions was investigated to obtain maximum storage time by using response surface methodology. Colour, polyphenol oxidase (PPO) activity and antioxidant activity were monitored to estimate quantitative changes of the product over refrigerated storage. The binary effects of collagen hydrolysate and ascorbic acid slowed polyphenol oxidase activity and prevented browning of potato surface colour. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging effect increased with the use of collagen hydrolysate and ascorbic acid at the beginning of storage and decreased at the end of storage. ABTS (2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) radical cation scavenging effect increased with the use of collagen and ascorbic acid during storage. The treatment of collagen hydrolysate and ascorbic acid in fresh-cut potatoes was successful in slowing PPO activity at the end of storage. Optimal conditions slowing down PPO activity at the end of storage are collagen 0.22% and ascorbic acid 0.30%.