Model for Predicting the pH of Foods Comprising Mixtures of Tomatoes and Low-Acid Ingredients

Abstract

The possibility of predicting the pH of home-canned foods comprising mixtures of tomatoes and low-acid ingredients was investigated. A quadratic model representing multi-component mixtures of tomatoes and nine low-acid ingredients, combined in various proportions, was tested. A 19-term equation for pH prediction, generated from the data, yielded a correlation coefficient of 0.9998 and a standard error of 0.11 pH unit. Tomato acidity was an important determinant of product pH. The equation was validated by comparing the predicted and observed pH of 55 representative products. Good agreement between these pH values was obtained. Criteria for recognition of low-acid products were established.