Structural model of fruit juice quality determining factors in product design and development

The purpose of this paper is to develop a structural model of factors determining quality of juices and to indicate major variables that are significant for further product development.

Juices of apples, oranges, grapefruits, black currants and mixed fruits were subjected to testing in order to determine the qualitative structure of fruit juices. The following determinations were carried out in all fruit‐juice samples: total solids (Brix), Brix other than sucrose, total acidity, pH, vitamin C content, total sugars, direct‐reducing‐sugar content, saccharose content and volatile acidity. In addition, a sensory assessment in a 5‐grade score scale was carried out, covering the sensory characteristics of taste, flavour and colour. Based on the results of sensory analysis, a total sensory quality index (TSQI) was calculated.

Values of the linear correlation coefficient were calculated, and force and direction of the interdependence between the measured juice quality factors were determined. Analysis of major components was applied to develop a model of the structure of quality characteristics of fruit juices and to disclose latent variables. It enabled disclosure of four independent (orthogonal) areas, which determine the quality of fruit juices, and explain 70 per cent of the total juice quality area. They are represented by: total sugars, total solids (Brix), sensory quality and total acidity.

The research enabled identification of factors determining the fruit juice quality. It may prove very useful for R&D departments, as it informs an enterprise of which areas to focus their product development efforts on. Reducing the number of the major factors to four reduces costs and shortens the time necessary for product design and development.