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

Svrha istraživanja: Ovo in vitro istraživanje obavljeno je kako bi se procijenio endogeni pH i ukupan topljivi sadržaj (UTS) koncentriranih te in natura razrijeđenih tropskih voćnih sokova. Ispitanici i postupak: Uzorak se sastojao od devet vrsta (Ananas sativus – ananas; Malpighia glabra – acerola; Spondias lutea – mombinska šljiva; Anacardium occidentale – orah cashew; Citrus sinensis – naranča; Mangifera indica – mango; Passiflora sp – gospodinova krunica; Citrulus vulgaris – lubenica i Vitis vinifera – grožđe). UTS koncentriranih i razrijeđenih sokova bio je izmjeren Abbeovim refraktometrom, a za pH se koristio potenciometar. Rezultati: Svi sokovi imali su pH vrijednosti niže od 5,5. Onima od mombinske šljive i lubenice izmjerena je najniža (2,8) i najviša (5,2) vrijednost. Moramo istaknuti da razrjeđivanje nije promijenilo pH. UTS koncentriranih sokova bio je u rasponu od 5,25 posto (acerola) do 16,0 posto (mango). Nakon razrjeđivanja, manji UTS izmjeren je u svim testiranim uzorcima. Zaključak: Voćni sokovi u tim istraživanjima imali su manje vrijednosti pH od kritičnih koje rezultiraju demineralizacijom zuba te se zato mogu smatrati potencijalno erozivnima. Iako razrjeđenje nije znatnije promijenilo vrijednosti pH, jako je smanjilo udjel šećera u pićima.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