eng Science and Education Publishing Journal of Food Security 2372-0107 2022-02-23 10 1 10 16 10.12691/jfs-10-1-2 JFS20221012 article Gilbert Owiah Sampson gosampson@uew.edu.gh 1 Emmanuel Ohene Afoakwa 2 3 Oluwakemi Cyrilla Ogunseye 3 Daniel Tetteh Amanquah 3 Faculty of Vocational Education, AAM-University of Skills Training and Entrepreneurial Development, Kumasi-Ghana Ghana Communication Technology University, Tesano, Accra-Ghana Response surface methodology and central composite rotatable design for K=2 was employed to analyze the combined effect of sugar concentration and acid balancing on the soluble solids, refractive index, water insoluble solids total acidity and pH of watermelon (Citrullus vulgaris) jam. Regression models were developed to predict the effects of the processing parameters on the studied indices. Significant interactions were observed between all the factors with high regression coefficients (61.78-98.34%). There was a significant (p¡Ü0.05) influence of the quadratic factors of pH and sugar concentration as well as the linear factor of pH on the soluble solids content, pH and refractive index but no significant influence of total acidity and water insoluble solids on watermelon jams. However, the linear and quadratic factors of pH showed no significant (p¡Ü0.05) influence on the refractive index of the watermelon jams. Sugar concentration influenced most of the quality indices whereas pH had only marginal influence on the studied parameters. http://pubs.sciepub.com/jfs/10/1/2/jfs-10-1-2.pdf response surface methodology refractive index regression models soluble solids water melon jam