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Effect of airflow rate and air temperature of flash dryer with horizontal spinner on drying of okara
August 5, 2014

Joko N.W. Karyadi*1, Findy A. Luthfi1, Nursigit Bintoro

(1. Department of Agricultural Engineering, Universitas Gadjah Mada, Yogyakarta, Indonesia)

Type of Presentation: ORAL


Okara is the byproduct of tofu production that it contains some nutrition and fiber. High moisture content and stickiness of the material causes slow drying if it is used conventionally methods. The objective of this research is determining the drying characteristic of okara using flash dryer with horizontal spinner. Flash dryer was constructed with rectangle shape of pipe (each side 0.12 m). Electric fin heater was used as heat source. In this study, using variation of the air flow rate are 0.1389 m3 / s, 0.1443 m3 / s and 0.1536 m3 / s, as well as variations in feed rate namely FR1 (33 kg / h) and FR2 (37 kg / h). Drying was conducted from the initial moisture content 70-80% to about 15-20% moisture content with a sample of 2 kg. Moisture content at the end of each cycle was measured. Data properties such as air temperature and humidity environment observed every minutes. Data of fineness modulus, diameter, density, and color lab testing were collected after drying. Ambient temperature and humidity data were used to calculate the efficiency of drying. Drying efficiency of okara using flash dryer were about 13-17%, whereas the heating efficiency were value ranged between 75-77%. Based on testing okara diameter ranged between 0604-0821 mm and the fineness modulus values ranged between 2.536-2.979. Density of dried okara are in the range between 0.2532 – 0.3774 g/cm3. The color of dried okara had brightness level (L *) ranged between 44.3-56.1, with a value of * 3.6-8.2 and b * values 17.6-19.6.

Keywords: okara, flash dryer, horizontal spinner, drying characteristic