The utilization of coconut wet processing waste as an emulsifier: effect of protein – pectin concentration and pH

Abstract The wet processing of virgin coconut oil produces by-products such as coconut skim milk and protein-rich solids. These substances are often not utilized effectively and are typically discarded into the environment. This fraction contains 16.38% protein, which can increase up to 80.30% if processed into concentrate. The high protein content in coconut waste can be utilized as an emulsifier in food products, offering a potential sustainable solution for utilizing agricultural by-products. However, the application of emulsifiers in food or beverage products remains challenging due to their poor functional properties. Addressing this limitation could contribute to the development of more effective natural emulsifiers for the food industry. The objective of this research was to determine the optimal conditions for forming complexes through electrostatic interactions between coconut waste protein concentrate and pectin, thereby enhancing the emulsifying properties of the resulting mixture. This research consisted of two stages. The first stage identified characteristics of coconut waste protein concentrate. The second stage determined the effect of process conditions on the formation of complexes via electrostatic interactions between coconut waste protein concentrate and pectin. Results showed that emulsifying properties increased with higher pectin concentration. The most effective complex was observed at a pectin-to-CPWC ratio of 0.7 (0.5% w/v CPWC and 0.35% w/v pectin at pH 4), with a zeta potential of –23.04 mV. In summary, a soluble complex between CPWC and pectin, formed by electrostatic interaction, can stabilize an oil-in-water emulsion. However, heat stability could be improved, as the electrostatic interactions are non-covalent and considered weak, and tend to be disrupted by heat.