A review on coconut testa: Nutritional attributes, physical properties, biological activities, and product innovation

• Coconut testa is rich in phyto-nutrients • These phytochemicals have a variety of biological activities with health benefits • Coconut testa oil is rich in beneficial fatty acids • Coconut testa flour can be used to develop functional foods Coconut testa (CT) is the brown color outer skin of the coconut flesh, a by-product of the coconut processing industry. It is often discarded or used to extract low-grade oil and the remaining residue is utilized for animal feed preparations. CT is a substance rich in phyto-nutrients such as polyphenolics, flavonoids, tannins, anthocyanins, etc. These phytochemicals are responsible for a variety of biological properties of CT, such as antioxidant, anti-hyperglycemic, anti-microbial and anti-inflammatory activities. Owing to these reasons, there has been a growing interest among researchers in utilizing CT for the production of value-added ingredients with health benefits. When CT is mildly dried and subjected to cold-press oil extraction, coconut testa oil (CTO) is produced with an edible grade residue. CTO is found to possess a fatty acid profile similar to that of regular coconut oil, but the level of specific fatty acids such as lauric, palmitic, oleic and linoleic acid showed differences. The studies on the defatted oil cake indicated that the main constituents of coconut testa flour (CTF) are carbohydrates (42-59 %), followed by protein (23-32 %) and fat (7-23 %). The de-fatted CT left behind in the oil extraction can be ground into flour and has been shown to be useful for developing novel product formulations. In recent times, different research groups have investigated many different aspects of CT and CTF. In this review, we intended for an in-depth analysis of research findings on CT, CTO and CTF.