COMPARING 3‐POINT VERSUS 9‐POINT JUST‐ABOUT‐RIGHT SCALES FOR DETERMINING THE OPTIMUM CONCENTRATION OF SWEETNESS IN A BEVERAGE

Abstract

ABSTRACT Just‐about‐right (JAR) scales are often used in research and development of food products. One of their uses is determining the optimum level of an ingredient. The purpose of this work was to compare the use of a 3‐point JAR scale analyzing the data using survival analysis statistics with a 9‐point JAR scale followed by linear regression analysis. It was also of interest to determine if a concentration range effect exists when determining the optimum concentration using a 3‐point JAR scale. Three different concentration ranges were used to determine the optimum level of sucrose in orange juices. The optimum concentrations obtained by both the 3‐point and 9‐point JAR scales were affected by concentration ranges. The optimum sucrose concentrations were 8.2% for the 9‐point scale and 13.1% for the 3‐point scale. A second experiment showed that 70% of the subjects preferred the 13.1% sample over the 8.2% sample. The 3‐point JAR scale combined with interval censoring statistics provided a more reliable optimum concentration level than the 9‐point JAR scale method. PRACTICAL APPLICATIONSThe optimum concentration obtained using the 3‐point Just‐about‐right (JAR) scale was more accurate then the value obtained from the 9‐point JAR scale in the sense that it was closest to values in commercialized beverages and was preferred in a direct comparison. Thus the 3‐point JAR scale followed by interval censoring statistics is a method to be pursued when measuring the optimum level of a food ingredient. This article also provides data confirming a concentration range effect when measuring the optimum concentration of a food ingredient. This range effect was present when using the 3‐point JAR scale and the 9‐point JAR scale. The use of multiple concentration ranges is a way to account for this effect.