PHYSICOCHEMICAL AND RHEOLOGICAL CHARACTERIZATION OF GUAVA PULP (<I>Psidium guajava</I> L.) VARIETIES HYBRID KLOM SALI, PUERTO RICO, D14 AND RED

Abstract

Rheological properties of fruit juices appear to be very much dependent of their varieties, state of ripening, concentration of juice/pulp and temperature variation. Typical values of flow behaviour index and consistency index are rather limited considering the varieties of guava fruits. In this work the guava pulp ( Psidium guajavaL.) was rheologically characterized in the varieties Hybrid of Klom Sali, Puerto Rico, D14 and Red cultivated in the department of Córdoba (Colombia); the pulps were obtained by means of refinery with mesh 1.5mm of opening. The rheological measurements were carried out in a Brookfield viscometer DVII+ Pro model, used the spindle Nº 5 for the varieties Klom Sali, Puerto Rico and Red, and Nº 6 for the variety D14. The pulps presented pH among 3.90 – 4.6, ºBrix among 9 - 10, acidity expressed as percentage of citric acid among 0.56 – 0.96% and maturity index among 9.38–17.94; were adjusted appropriately to Oswald-de Waele model or power law (R2 ≥ 0.989), behaving as a pseudoplastic fluid (n ≤ 0.307) and presenting tixotropic percentages the variety Puerto Rico (14.16%), Red (18.54%) y D14 (18.48%).

Keywords

• apparent viscosity
• pseudoplastic
• power law model
• tixotropy.