Optimization of Degumming and Deacidification processes for Coffee Oil

To address the issues of low recycling value for defective coffee beans and coffee grounds, and their environmental pollution. In this study, coffee oil was extracted from dark-roasted Arabica coffee beans, and its refining process was optimized through acid-catalyzed degumming and alkali neutralization. The effects of each processing stage on the physicochemical properties, fatty acid profile, and volatile compound composition of the coffee oil were systematically investigated. The results indicated that through single-factor and orthogonal experiments, the optimal parameters for the acid-catalyzed degumming process were as follows: citric acid solution concentration of 60.0%, citric acid dosage of 0.25%, water addition of 2.0%, degumming temperature of 45 °C, and hydration time of 40 min. Under the aforementioned conditions, the degummed oil was prepared and subsequently subjected to alkali refining for deacidification. Through single-factor and response surface experiments, the optimal process parameters for alkali refining deacidification were determined as follows: sodium hydroxide solution concentration 10.0%, excess alkali amount 0.20%, refining temperature 50 °C, and reaction time 20 min. The physicochemical properties of the coffee oil were analyzed before and after refining. The results showed significant reductions in acid value (94.7%), peroxide value (36.6%), and moisture/volatile matter content (78.74%). While the fatty acid composition and volatile compound profiles remained largely consistent, minor quantitative variations were observed.