DEHYDRATION OF AMLA SEGMENTS IN A SOLAR TUNNEL DRYER

U. PRIYANKA¹*, A. CAROLIN RATHINAKUMARI², SENTHIL KUMAR³, TIWARI^4
1University of Agricultural Sciences, GKVK, Bengaluru, 560065, Karnataka, India
²ICAR-Indian Institute of Horticultural Research, Hesaraghatta, Bengaluru, 560089, Karnataka, India
³ICAR-Indian Institute of Horticultural Research, Hesaraghatta, Bengaluru, 560089, Karnataka, India
⁴ICAR-Indian Institute of Horticultural Research, Hesaraghatta, Bengaluru, 560089, Karnataka, India
* Corresponding Author : priyapreksha@gmail.com

Received : 28-12-2016     Accepted : 01-02-2017     Published : 12-02-2017
Volume : 9     Issue : 7       Pages : 3853 - 3858
Int J Agr Sci 9.7 (2017):3853-3858

Keywords : Solar tunnel dryer, Drying, Moisture content, Amla Segments, Drying Models
Conflict of Interest : None declared
Acknowledgements/Funding : The author thanks Indian Council Of Agricultural Research, New Delhi, India for funding during research work and also university of agricultural sciences for their kind support and encouragement
Author Contribution : U. Priyanka- Involved in conducting the research; Dr. A.Carolin rathinakumari, Dr. Senthil kumar and Dr. Tiwari- provided guidance for conducting the research and furnished the necessary inputs required.

In this study, a solar tunnel dryer of 6 x 3x 2.7 m (LxWxH) constructed with galvanized frame structure and covered with 200 µ UV-stabilized LDPE sheet. Two fresh air inlets of 0.6 x 0.3 msize and two exhaust fans each of 9’’ diameter and 50 watt capacity were installed at the rear side and front side of the dryer, respectively. The amla segments pre-treated with 2% sodium chloride, 0.1 % potassium meta-bi-sulphite solutions and untreated slices were subjected for drying. Results obtained from this experiment showed that in solar tunnel dryer, the drying required 11-13 h for various pre-treated amla segments to reduce the initial moisture content ranging from 521.46 to 422.32% (dry basis) to final moisture content in the range of 17.39 to 17.01 % (dry basis) and in open yard sun drying, it required 15-18 h for various pre-treated amla segments to reduce from moisture content of 520.13 to 430.13 % (dry basis) to safe storage moisture content of 17.83 to 17.09% (dry basis) at different drying air temperatures and relative humidities. Two drying models were fitted to experimental drying data of amla segments namely Logarithmic model and Henderson-Pabis model and Logarithmic model was found to be the best fit to describe the drying behavior of amla segments. The use of solar tunnel dryer leads to considerable reduction of drying time in comparison to sun drying. The amla segments being dried in the solar tunnel dryer were completely protected from rain, insects and dust.