pH and Total Soluble Solid Content in Concentrated and Diluted in Natura Tropical Fruit Juices

摘要

Objectives: This in vitro study evaluated the endogenous pH and the content of total soluble solids (TSS) in concentrated and diluted in natura tropical fruit juices. Material and Methods: The sample was composed by 9 kinds of tropical fruits (Ananas sativus - pineapple; Malpighia glabra - acerola, Spondias lutea - hog plum; Anacardium occidentale - cashew fruit; Citrus sinensis - orange; Mangifera indica - mango; Passifl orasp - passion fruit; Citrulus vulgaris - watermelon and Vitis vinifera - grape). For concentrated and diluted juices, TSS content was determined by refractometry, using the Abbé refractometer, and the pH was determined by potentiometry. Results: All evaluated juices presented pH values lower than 5.5. The hog plum and watermelon juices presented the lowest (2.8) and highest (5.2) pH values, respectively. The dilution of the juices, however, did not produce pH alterations. For the concentrated juices, the TSS content ranged from 5.25% (acerola) to 16.0% (mango). After dilution, a decrease in the TSS content was observed in all tested samples. The fruit juices evaluated in this study presented lower pH values than the critical value assumed for dental demineralization, being therefore, potentially erosive. Conclusion: Although the dilution of the fruit juices did not produce expressive alterations in the pH values, it reduced remarkably the sugar content of the beverages.