Development of processing techniques for underutilized fruit trees in Sri Lanka (Nelli (Phyllanthus emblica ), Goraka ( Garcinia cambogia) , Tamarind ( Tamarindus indica)

Abstract

Gotaka (Gardnia cambogia),Tamarind (Tamarindus indica) , and Nelli (Phyllanthus emblica) are important but underutilized fruit tree in Srilanka. Sun drying is the major indigenous method of preservation of these fruits. However current processing techniques of these fruits are not satisfactory in Snlanka, Thus the quality of final product is always low and producers always receive low prices for their products. The objectives of this study were to investigate the indigenous processing and storage techniques of nelli, goraka and tamarind and to identify the essential steps for the improvement of appropriate processing techniques for the improvement of appropriate processing techniques for these products For the evaluation of indigenous method of processing raw and processed samples of the above fruits were collected from Kandy and Kuliyapitiya. Processing methods of those fruits were studied gathering information from local producers of Kandy and Kuliyapitiya area and quality parameters such as moisture contents, presence of microorganisms, color and impurities of the processed products were investigated. Drying characteristic of above fruits were studied under dynamic controlled environment conditions with combinations of temperature and relative humidities. The test were fitted to the logarithmic drying model using a method of least squares. H test of sun drying was conducted to simulate the indigenous drying methods.Moisture contents (dry basis) of the processed products collected from the sales outlets were in the range of 21% to 66% for Goraka, 13% to 33% for Nelli, 15% to 61% for Tamarind.Average amount of processed samples of goraka, nelli and tamarind were infested with fungus and insects. Color of the processed products from the sales outlets and under xperimental condition was favorably changed, sun drying of goraka and nelli required 4 and more than 5 days respectively to reach acceptable moisture content of 21% and 13%.( 22hours after drying nelli at 40 °c and RH 40% reached the dry basis moisture content. The drying constant (k) of the logarithmic drying model varies from 0.0115 to 0.2258 for the used combinations of temperature and RH). Result of this study revealed that, dehydration is mainly depend on the RH of the drying environment, and the drying constant k influence the quality of the dried products. Since sun drying depend on the natural climatic condition. It is difficult to control drying parameters with the traditional method of drying. Therefore it is recommended to use convectional air drying under controlled conditions to improve the Quality of the processed products.