Chemical Engineering Department, Laboratory of Food and Agricultural Industries Technologies, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Molecules. 2022 May 6;27(9):2971. doi: 10.3390/molecules27092971.
The use of vacuum cycles for the cold extraction of coffee is a new process that leads to a significant reduction in process time of Cold Brew compared to conventional methods. This research aimed at specifying the necessary parameters for producing a consumer-accepted cold brew coffee by applying vacuum cycles. This was achieved by investigating the effect of the number of cycles and of the applied pressure (vacuum) on the physicochemical characteristics of the cold brew coffee, i.e., total dissolved solids (TDS%), pH, acidity, phenol and caffeine content and color. Furthermore, sensory evaluation took place by members of the Specialty Coffee Association of America (SCAA) to specify parameters such as coffee blend, coffee/water ratio, total water hardness and grind size and secondly to determine the optimal pressure and number of cycles for a tasty final beverage. The sensory and physiochemical characteristics of cold extraction coffee were investigated by Principal Component Analysis (PCA). It became evident that coffee extraction by applying two vacuum cycles at 205 mbar pressure produced the lowest intensity of physiochemical properties (caffeine, phenols, acidity, TDS% and pH), and the highest score of sensory characteristics (fragrance, body, acidity, flavor, balance, and aftertaste). Caffeine and phenol concentration of the optimal beverage were 26.66 ± 1.56 mg/g coffee and 23.36 ± 0.79 mg gallic acid/g coffee respectively. The physiochemical characteristics were also compared to a beverage of hot extraction of the same blend and ratio of coffee to water.
利用真空循环进行冷萃咖啡的提取是一种新工艺，与传统方法相比，冷萃咖啡的提取时间显著缩短。本研究旨在通过应用真空循环来确定生产消费者可接受的冷萃咖啡所需的参数。通过研究循环次数和施加压力（真空）对冷萃咖啡的物理化学特性（即总溶解固体 (TDS%)、pH 值、酸度、酚类和咖啡因含量和颜色）的影响来实现这一目标。此外，美国特种咖啡协会 (SCAA) 的成员进行了感官评估，以确定参数，如咖啡混合、咖啡/水的比例、总水硬度和研磨粒度，然后确定美味最终饮料的最佳压力和循环次数。通过主成分分析 (PCA) 研究了冷萃取咖啡的感官和物理化学特性。显然，在 205 毫巴的压力下应用两个真空循环进行咖啡萃取可产生最低的物理化学性质强度（咖啡因、酚类、酸度、TDS%和 pH 值），并获得最高的感官特征评分（香气、口感、酸度、风味、平衡和余味）。最佳饮料的咖啡因和酚浓度分别为 26.66±1.56mg/g 咖啡和 23.36±0.79mg 没食子酸/g 咖啡。还将该物理化学特性与相同混合和咖啡与水比例的热萃取饮料进行了比较。
