Morphological, Structural, and Physicochemical Characterization of Starch Extracted from Madu (Cycas sp.) Grown in Sri Lanka

Abstract

Cycas sp. is an underutilized carbohydrate source in Sri Lanka that holds significant potential for integration into the human diet. Starch obtained from Cycas could serve as a viable alternative to commonly used starch sources in food applications. This study focused on characterising Cycas starch, evaluating its structural, physicochemical, and morphological properties to understand its functionality and potential uses. The proximate composition revealed low crude protein (0.70 ± 0.02%), crude fat (0.27 ± 0.06%), and ash (0.23 ± 0.01%), indicating higher purity in extracted starch. The moisture content was 8.23 ± 0.54%, which is within the acceptable range for starch stability and storage. Microscopic examination showed predominantly spherical shaped granules, with diameters ranging from 0.68 to 1.72 μm. FTIR spectral analysis confirmed the typical carbohydrate nature of the starch, with characteristic absorption bands consistent with those of standard starches. XRD pattern revealed that Cycas starch was a type-A with relative crystallinity of 27.92%. The amylose content was found to be 15.89 ± 2.62%, suggesting a lower amylose level while the bulk density and pH were recorded as 0.56 ± 0.00 g/ml and 7.28 ± 0.06, respectively. Colour measurements showed L*, a*, and b* values of 97.51 ± 0.41, -0.42 ± 0.13, and 0.57 ± 0.12, with the notably high L* value indicating a higher level of whiteness. Water-holding and oil-holding capacities were 1.39 ± 0.09 g/g and 1.15 ± 0.18 g/g, respectively. Solubility and swelling power both increased with temperature, reaching their maximum values at 80 °C, demonstrating typical thermal behaviour of starch. The study shows that the underutilized starch from Cycas sp., exhibit physicochemical and functional properties suitable for food industry applications, and holds potential for use in various food formulations.