Comparison of inter-varietal differences in chemical composition and nutritional properties of coconut testa flour

Abstract

Coconut testa is the brown colour thin outer covering of the coconut endosperm. An attempt was made to convert coconut testa into flour for bakery products. In this study, chemical composition and nutritional properties of coconut testa flour of four local cultivars, namely, San Raman, Gon Thambili, Ran Thambili and Tall × Tall were compared against those of a commercial hybrid grown in Sri Lanka. Partially defatted coconut parings of each cultivar were oven-dried and ground into coconut testa flour. Moisture, crude fat, ash and crude protein contents of coconut testa flour were determined according to AOAC methods. The carbohydrate content was calculated by the difference. Inter-varietal differences of fatty acids and micro-mineral distributions were also determined. The main constituent of coconut testa flour regardless of cultivar was carbohydrate (42.55–59.24 %) followed by protein (23.82–32.22 %) and fat (7.93–23.49 %). Commercial hybrid had the highest carbohydrate content (59.24 %) while the minimum carbohydrate content was recorded for San Raman variety (42.55 %). Highest protein content was observed in Gon Thambili (32.22 %) variety while the least was observed in commercial hybrid (23.82 %). The highest fat content was noted in San Raman variety (23.49 %). Tall × Tall variety contained the least fat content (7.93 %). Maximum ash content was observed in Ran Thambili variety (5.30 %) while the least ash content was for Gon Thambili variety (3.70 %). Highest moisture content was prevalent in San Raman variety (4.27 %) while the least was observed in commercial hybrid (2.27 %). These results suggested that coconut testa flour is a nutritious substance, which provides value addition to the under-utilised by-product of coconut processing industry.