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Coconut testa, a brown skin covering of a coconut endosperm, is a rich source of phenolics. It is one of the by-products obtained in the coconut processing industries and currently underutilized despite being rich in phenolic compounds. A study was conducted to identify the suitable solvent system for maximum extractability of total phenolic content (TPC) and total flavonoid content (TFC) with antioxidant potential from the testa. Individual phenolic acids and flavonoids of different solvent extracts were also determined using UPLC-H class coupled with TQD-MS/MS. The TPC and TFC ranged from 4.9 to 167 mg GAE/g and 8.84–115 mg QE/g defatted testa, respectively; significant differences were observed for various solvent systems studied. Acidification of solvents significantly increased the extractability of TPC and reduced the extractability of TFC. A total of 28 phenolics comprising 16 phenolic acids and 12 flavonoids were identified. Protocatechuic acid, p -coumaric acid and ferulic acid are the major phenolic acids identified whereas, catechin, apigenin and kaempferol are the major flavonoids identified. In summary, this study proved that coconut testa is a natural source of multiple phenolics acids and flavonoids with potent antioxidant capacity, and it can be used as a natural source of antioxidants. [ABSTRACT FROM AUTHOR]

Rice and maize are commonly used for the production of extrudates and incorporation of nutritionally rich materials is prime important to make extrudates nutritionally superior. Coconut haustorium, a nutrient rich spongy tissue formed during coconut germination, was added to rice and maize (1:1) flour at levels of 0%, 10%, 20% and 30% (w/w) by replacing the maize and extruded in twin-screw extruder. Effect of addition of haustorium on the physico-chemical parameters like bulk density, expansion ratio, water absorption index, water solubility index, hardness, breaking force, breaking strength, compressive strength, color parameters like L*, hue, and chroma value, sensory characteristics and biochemical parameters like proximates, minerals, phenolics, flavonoids and antioxidant potential in the extrudates were studied. Results indicated that the addition of haustorium had a significant effect on parameters studied. Incorporation of haustorium resulted in less expanded, lengthy, dark colored, hardened, protein, minerals, phenolics and flavonoids rich extrudates with high anti-oxidant activity. A combination of 50% rice, 30% maize and 20% haustorium was found suitable for healthy and nutritious extrudates preparation based on the biochemical constituents and overall sensory acceptability. [ABSTRACT FROM AUTHOR]