Recovery and antiforming mechanism of natural antifoamer from coffee-spent

Abstract

Foams generated during most food manufacturing processes can cause several serious problems such as the loss of raw materials, interference of process automation. Therefore, artificial silicone-base anti-foamers are widely used to suppress foam generation in food industry. In this study we are trying to extract natural anti-foamer replacing artificial anti-foamer from coffee-spent, a by-product generated from instant coffee manufacturing process. Four kinds of organic solvents, methanol, ethanol, butanol, hexane, were selected to extract oil-soluble materials in coffee-spent. A simple and rapid method of anti-foaming activity measurement was developed for this study. Methanol-extract was best in anti-foaming activity followed by ethanol-extract and butanol-extract in that order. Hexane-extract showed no activity. Anti-foaming activity was not dependent on the extraction time. The order of the activity was well matched with the polarity order of solvents to be used for extraction. Refining steps (degumming, neutralization, bleaching, deodorization) for methanol- and ethanol-extract were carried out step by step to identify the compound that is responsible for the activity. In contrast to the higher anti-foaming activity of crude and degummed oil, the activity was drastically decreased after neutralization. The activity of bleached and deodorized samples was almost similar to that of neutralized one. The fact that most of the free fatty acid and about 85% of monoglyceride were removed from neutralization step means the two compounds appear to play a crucial role in the action of anti-foaming. The higher anti-foaming activity of crude and degummed oil could be well explained by the spreading theory proposed by Ross et al..