Stability and content of anthocyanins in Peruvian purple potato INIA 328 - Kulli Papa

The influence of temperature, extraction time and solvent ratio on the anthocyanin content extracted from Peruvian purple potatoes INIA 328 – KULLI were investigated using conventional extraction with acidified ethanolic aqueous solvent. The preservation rate (R), thermal degradation rate (k) and the half-life () of purple potatoes anthocyanin extract at different temperatures were determined. In addition, the color change of the anthocyanin extract was examined against different pH using UV-Visible spectroscopy. The results showed an anthocyanin content of 75.71 mg/100g of fresh weight (FW) obtained by an extraction temperature of 40 °C, for 4 hours and using a solvent ratio of 5 mL/g. On the other hand, thermal kinetic degradation indicates that 98 % of the anthocyanin content can be preserved for up to 6 hours at 40 °C. Better results were observed by keeping anthocyanin solutions at 4 °C in the absence of light, reaching a preservation rate of 99 % after one month of storage.