Effects of sugar composition on shelf life of hard candy: Optimization study using D-optimal mixture design of experiments

The purpose of this study was to determine the sugar formulation that maximizes the shelf life and critical moisture content of hard candy and to verify the relationship between the response variables. The method used was the mixture design of experiments. Experimental points were determined using a D-optimal mixture design. Industrial-scale tests were conducted using three commercial sugars commonly found in hard candies. The models were fitted to the experimental results and evaluated via an analysis of variance. There was a maximum point (58.17 d) for the accelerated shelf life model, which was 0.600, 0.200, and 0.200 for the mass fractions of sucrose, 40 DE corn syrup, and 20 DE high-maltose corn syrup, respectively; the maximum critical moisture content (3.88%) was 0.593, 0.228, and 0.179, respectively. The optimum formulation resulted in a product whose estimated shelf life extended 7 months beyond the expiration date usually used in the industry. Practical Applications The results have implications for increasing the shelf life and agility in the development of new products. A practical and low-cost method for determining the critical moisture content using accelerated tests in the confectionery industry is proposed. This study is a direct application of the mixture design of experiments on an industrial scale and provides significant results not found in the literature.