Protein and surfactant effects on the stability of sterilized coconut milk.

Coconut milk is an oil-in-water (o/w) emulsion with low emulsion stability. Therefore, the addition of synthetic small molecular weight (MW) surfactants is required in the production of thermally processed coconut milk. The objective of this study was to investigate the content of coconut protein at the oil-water interface of oil droplets in coconut milk, together with the influences of small MW surfactants, namely sucrose monostearate and polyoxyethylenesorbitanmonooleate within the concentration range of 0.10 – 0.20 %, and sodium caseinate (0 – 3 %) on the stability and oil droplet size distribution of sterilized coconut milk (121 C, 15 min), which contained 10 % fat and 1.37% coconut proteins stored for 2 weeks. It was found that using 0.2 % small MW surfactants could not stabilize the coconut emulsion. However, the minimum concentration of 1 % sodium caseinate added to coconut milk was able to maintain the stability of sterilized coconut milk during storage. There was no phase separation and the Z-average size of oil droplet was around 500 nm.