Effect of temperature and PH value on the stability of bioactive compounds and antioxidative activity of juice from colour‐fleshed potatoes

Abstract

SummaryThe colour‐fleshed potatoes represent a good raw material for the extraction of juices with a high content of biologically active compounds and a high antioxidant activity. The blue‐fleshed potatoes turned out to be a rich source of total polyphenols, as they had approximately 3.5 times higher content of identified anthocyanidins. Regardless of anthocyanin composition, all juices made of colour‐fleshed potatoes were highly stable. Both, high temperature, exposure time to these temperatures, and medium pH had no significant effect on changes in total polyphenols content of potato juices. The juices examined, especially these made of blue‐fleshed potatoes, demonstrated a higher ABTS+ stability during their heating than during pH changes. In addition, a higher antioxidant activity of juices was determined at neutral and alkaline than at acidic pH value of the medium.