36E-32

O. Gomez-Palomares, Dept. de Ingeniería Química y Alimentos, Univ. de las Américas, Puebla, Sta. Catarina Martir, Cholula, Puebla, 72820, Mexico, A. ARGAIZ, Dept. de Ing. Química y Alimentos, Univ. de las Américas, Puebla, Sta. Catarina Martir, Cholula, Puebla, 72820, Mexico, E. Palou, Center for Engineering Education, Univ. de las Americas, Puebla, Cholula, Puebla, 72820, Mexico, and A. Lopez-Malo, Dept. de Ingeniería Química y Alimentos, Univ. de las Américas-Puebla, Santa Catarina Mártir, Cholula, Puebla, 72820, Mexico.

Tropical fruits have limited storage life. Therefore, they are often preserved in order to have a supply throughout the year. Due to the abundance and highly marked season of tamarind losses are very high and producers are searching alternatives such as pasteurized puree and/or nectar. Kinetics of First Change on Flavor (FCF), color changes and thermal inactivation of pectinesterase (PE) inactivation were evaluated in tamarind puree and nectar subjected to several thermal treatments in a temperature range of 75 to 88° C. Tamarind puree (pH 2.6 and 18° Brix) and nectar (prepared with 35% puree and sucrose syrup to attain pH 3.1 and 12°Brix) were subjected to selected pasteurization treatments. A sensory trained panel and balanced triangle tests were used to determine the dependence on temperature of FCF. PE activity was determined after every treatment with the sensitized jelly test procedure (TIT). Color changes were determined using a reflectance color meter and transformed into minimal color differences. For FCF and TIT the logarithm of maximum and minimum heating time that gave a positive and negative result for each treatment temperature were plotted to obtain z values. Z value for the TIT was 37.9° C for the puree and 34.2° C for tamarind nectar. FCF z values varied from 56.8 for nectar to 66.1° C for the puree. Different F=1 minute temperatures were obtained being lower for enzyme TIT. Minimal color differences were for both products lower than 1.6 demonstrating a no detectable color change during tamarind product heating. These results allow designing pasteurization treatments at temperatures higher than 90° C that assure PE inactivation without detectable changes in flavor or color. Pasteurization processes designed on enzyme TIT assure high quality tamarind products with undetectable color and flavor changes.

Session 36E, Fruit & Vegetable Products: General
8:30 AM - 12:00 PM, Monday AM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana