Regression analysis for determination of antioxidant activity of coconut sap under various heating temperature and concentration of lysine addition

Abstract

This research aimed to determine the antioxidant activity of coconut sap added by different concentration of lysine during the heating process by means of regression analysis. This regression can be utilized to predict the antioxidant activity of coconut sap. A number of antioxidant parameters, i.e. total phenolic content, browning intensity, DPPH scavenging activity, and chelating activity, were measured using standard methods. The results showed that the changes in the total phenolic content of coconut sap against temperature during heating process followed a logarithmic regression function. The correlation between total phenolic content and heating temperature was quite strong until the temperature reached 100°C. Moreover, the changes in both browning intensity and DPPH scavenging activity of coconut sap against heating temperature followed an exponential regression. A quadratic regression function can represent the relationship between the chelating activity of coconut sap and heating temperature since the correlation of those parameters was relatively strong in the temperature range of 28-100°C. This study showed that the changes in total phenolic content, browning intensity, DPPH scavenging activity, and chelating activity of coconut sap during heating can be determined using regression analysis.