VISKOSITAS PUREE BUAH NAGA PUTIH (Hylocereus undatus) PADA BERBAGAI SUHU

Abstract

The physical properties of white dragon fruit puree such as viscosity is an important and relevant data required for designing the processing method and equipment. This study was aimed to identify the effects of temperature and concentration on the viscosity values of white dragon fruit puree. The puree samples were prepared in various concentrations (10, 12 and 14%TS) using the fresh white dragon fruis that obtained from the farmers in the Rembangan area in the district of Jember. These samples were then measured their viscosity using a digital Brookfield viscometer (RVDV-II + Pro) at temperatures of 20, 25, and 30°C. The viscosity measurements were done by means of a disc spindle under speeds of 0.5, 1.0, 2.5 and 5.0 RPM respectively. The results showed that an increase in the fruit purees concentration from 10 to 14%TS increased the viscosity values from 4530 to 11790cP. Conversely, the increasing of puree temperatures from 20 to 30°C caused the fruit puree viscosity to decrease between 11790 and 8800cP. It was expected that additional speed of spindle during measurement decreased the viscosity value of dragon fruit puree