ẢNH HƯỞNG CỦA NỒNG ĐỘ CaCl2, NHIỆT ĐỘ SẤY VÀ THỜI GIAN SẤY ĐẾN CHẤT LƯỢNG BỘT ỔI SẤY LẠNH

Abstract

This study aimed to investigate the effects of CaCl₂ concentration of soaking water before drying, drying temperature and drying time on the quality of dried guava pulp based on moisture content, color, vitamin C content and sensory quality using a heat pump dryer. Guava was sliced at approximate 0.15 cm thickness, treated with CaCl₂ concentrations of 2, 3, 4% and 5% (control 0%) to limit the color loss and reduce the viscosity of guava during drying, then dried and finely ground to produce guava powder. The results showed that the concentration of CaCl₂ 4% brought to a brighter color and higher sensory quality of the product. The effect of temperature on the quality of dried guava powder was investigated at the temperature of 45, 50, 55 and 60^oC. The effect of drying time was investigated every 2 hours on moisture content from the beginning of drying and at 16, 18 and 20 hours after drying on vitamin C and sensory properties. The results indicated that guava dried at 50^oC for 18 hours gave moisture of 11.73% (< 13%), vitamin C content was 156 mg, sensory properties of guava powder were at "like moderately" and "like very much".