Physicochemical and functional properties of protein concentrate from by-product of coconut processing

- Glutelin was the predominant protein fraction in by-product of coconut processing.
- Protein powders from milk cake provided higher water and oil absorption capacities.
- Protein powders from oil cake showed a good foaming and emulsifying properties.
- Coconut protein cakes can be solubilized in both acidic and alkaline solutions.

Coconut cake, a by-product from milk and oil extractions, contains a high amount of protein. Protein extraction from coconut milk cake and coconut oil cake was investigated. The supernatant and precipitate protein powders from both coconut milk and oil cakes were compared based on their physicochemical and functional properties. Glutelin was the predominant protein fraction in both coconut cakes. Protein powders from milk cake presented higher water and oil absorption capacities than those from oil cake. Both protein powders from oil cake exhibited better foaming capacity and a better emulsifying activity index than those from milk cake. Coconut proteins were mostly solubilized in strong acidic and alkaline solutions. Minimum solubility was observed at pH 4, confirming the isoelectric point of coconut protein. Therefore, the coconut residues after extractions might be a potential alternative renewable plant protein source to use as a food ingredient to enhance food nutrition and quality.