• The Effect of High Pressure Processing on Antioxidant Activity of Irish Potato Cultivars

      Tsikrika, Konstantina; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 17/F/299 (MDPI, 2019-04-16)
      The effect of High Pressure Processing (HPP) on Irish potato cultivars’ antioxidant activity (AOA) was examined. High Pressure Processing at 600 MPa for 3 min was applied to two coloured (Rooster and Kerr’s Pink) and two white (Saxon and Gemson) Irish potato varieties. Antioxidant activity was assayed spectrophotometrically by ferric reducing antioxidant power and diphenyl-1-picrylhydrazyl methods. No statistically significant (p ≥ 0.05) change in antioxidant activity was observed in both the AOA methods irrespective of the HPP treatments, although a slight increase in the activity was noted in the majority of the HPP treated samples. This implies that HPP treatment has little role in improving the functional qualities, and can be tailored to improve the quality and safety of the commonly consumed potatoes.
    • The Effect of High Pressure Processing on Polyphenol Oxidase Activity, Phytochemicals and Proximate Composition of Irish Potato Cultivars

      Tsikrika, Konstantina; O’Brien, Nora; Rai, Dilip K.; Department of Agriculture, Food and Marine; 17/F/299 (MDPI AG, 2019-10-19)
      Polyphenol oxidase (PPO) activity, proximate composition, and phytochemicals were determined in four common Irish potato cultivars following a high pressure processing (HPP) at 600 MPa for 3 min. PPO activity was significantly (p < 0.05) lower in all HPP treated samples, while the overall proximate composition was not affected. The total phenolic content was significantly higher in the HPP treated samples. Chlorogenic acid levels significantly decreased with simultaneous increase of caffeic acid and p-coumaric acid levels upon HPP treatment. No significant changes were observed in rutin and ferulic acid levels, although their levels varied, depending on the potato cultivars, while the levels of cytotoxic glycoalkaloids (α-solanine and α-chaconine) remained unaltered.