咖啡精油超临界CO2萃取工艺优化及理化特性分析

以云南保山小粒咖啡豆为对象，根据国家标准，测定生、熟咖啡豆的营养成分，在单因素实验的基础上，以响应面优化超临界CO₂萃取咖啡精油的工艺参数；测定生、熟咖啡精油理化指标，并通过气相色谱-氢火焰离子化检测器（GC-FID）分析生、熟咖啡精油的脂肪酸组成。结果表明:经烘焙处理后，熟咖啡豆中水分、水浸出物、咖啡因、总糖、粗纤维和粗脂肪含量与生咖啡豆中的存在显著差异（P<0.05）；超临界CO₂萃取生咖啡精油的最佳工艺条件为萃取压力25 MPa，萃取温度54 ℃，萃取时间150 min，在此条件下咖啡精油萃取得率为13.98%。烘焙处理前后，咖啡精油各常规理化指标无显著差异，且均符合国家标准要求。通过GC-FID分别检测到15和16种脂肪酸，其中亚油酸、棕榈酸、硬脂酸和油酸等为主要脂肪酸，烘焙对咖啡豆脂肪酸组成影响不明显，但各脂肪酸的含量存在一定差异。烘焙对咖啡豆及咖啡精油的各项指标均有一定程度的影响，为云南地区咖啡产业发展提供科学依据。

Optimization of Supercritical CO2 Extraction Process and Analysis of Physicochemical Properties of Coffee Essential Oil

Taking Baoshan small grain coffee beans from Yunnan Province as the object, the nutrient components of raw and cooked coffee beans were determined according to national standards. On the basis of single factor experiment, the process parameters of supercritical CO₂ extraction of coffee essential oil were optimized by response surface（RSM）. The physical and chemical indexes of the essential oil of raw and cooked coffee were determined. The fatty acid composition of raw and cooked coffee essential oil was analyzed by gas chromatography-hydrogen flame ionization detector (GC-FID). The results showed as follows: after roasting, the contents of water, water extract, caffeine, total sugar, crude fiber and crude fat in cooked coffee beans were significantly different from those in raw coffee beans (P<0.05); The optimum conditions of supercritical CO₂ extraction were as follows: extraction pressure 25 MPa, extraction temperature 54 ℃ and extraction time 150 min. Under these conditions, the extraction yield of raw coffee essential oil was 13.98%. Before and after roasting treatment, there was no significant difference in the routine physical and chemical indexes of coffee essential oil, and all of them met the requirements of national standards. 15 and 16 fatty acids were detected by GC-FID, among which linoleic acid, palmitic acid, stearic acid and oleic acid were the main fatty acids. Roasting had no significant effect on the fatty acid composition of coffee beans, but there were some differences in the content of each fatty acid. In this study, roasting has a certain degree of influence on the indicators of coffee beans and coffee essential oil, which provides a scientific basis for the development of coffee industry in Yunnan.