ABSTRACT
Phenolic compounds contribute to the characteristic flavor of ripe fruits. This chapter examines the principal modifications related to the presence of phenolic compounds during the processing of fruits, with particular stress on fruit beverages. The organoleptic and biochemical characteristics of fruits may be profoundly modified by the appearance of brown pigments whose color is superposed on the natural colors. Some browning may be nonenzymatic in origin and result from the Maillard reaction when mixtures of amino acids and carbohydrates are heated. In order to evaluate the browning potential of a fruit, the enzymes involved and their substrates should be put into close contact by grinding and the resulting coloration measured. There are two possible types of approach: those based on measurements of reflectance using a differential tristimulus colorimeter; and those based on measurements of absorbance of solutions after purification by centrifugation and filtration.
