Liu Yunjiao, Chua Xin Yi, Dong Wenjiang, Lu Yuyun, Liu Shao-Quan
Department of Food Science and Technology, Science Drive 2, Faculty of Science, National University of Singapore, Singapore, 117542, Singapore.
Spice and Beverage Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wanning, Hainan, 571533, China.
Curr Res Food Sci. 2022 Aug 19;5:1276-1286. doi: 10.1016/j.crfs.2022.08.002. eCollection 2022.
Spent coffee grounds (SCG) disposal is an environmental problem. These residues from coffee brewing and instant coffee production have potential to produce novel alcoholic beverages. SCG valorization through sequential alcoholic and malolactic fermentation was investigated using a yeast, Concerto and a lactic acid bacterium (LAB), Lalvin 31 in this study. Our results showed that sequential inoculation prevented early death of yeast confronted when simultaneous inoculation was adopted, allowing for growth and persistence of both yeast and LAB till the end of fermentation. Adequate ethanol production (4.91 ± 0.13 %, v/v) with low residual sugar content was also attained. In addition, relatively lower levels of acetic, lactic, and succinic acids were produced by sequential inoculation than that of simultaneous inoculation. Furthermore, SCG hydrolysates fermented via sequential inoculation had the widest variety of volatiles (e.g. esters and ketones). Overall, our results indicated that sequential inoculation of and in SCG hydrolysates might be a way to develop novel beverages with pleasant flavor profiles.
废弃咖啡渣（SCG）的处理是一个环境问题。这些来自咖啡冲泡和速溶咖啡生产的残渣有潜力生产新型酒精饮料。本研究使用酵母Concerto和乳酸菌Lalvin 31，通过顺序酒精发酵和苹果酸-乳酸发酵对SCG进行增值利用。我们的结果表明，采用顺序接种可防止同时接种时酵母过早死亡，使酵母和乳酸菌在发酵结束前都能生长并存活。同时还获得了足够的乙醇产量（4.91±0.13%，v/v）且残余糖含量较低。此外，顺序接种产生的乙酸、乳酸和琥珀酸水平比同时接种时相对更低。此外，通过顺序接种发酵的SCG水解产物具有最丰富的挥发性成分（如酯类和酮类）。总体而言，我们的结果表明，在SCG水解产物中顺序接种Concerto和Lalvin 31可能是开发具有宜人风味新型饮料的一种方法。
