Ji T, Alvarez V B, Harper W J
Department of Food Science and Technology, The Ohio State University, Columbus 43210, USA.
J Dairy Sci. 2004 Jul;87(7):1986-92. doi: 10.3168/jds.S0022-0302(04)70015-6.
Quantification of water-soluble volatile free fatty acids (FFA) and free amino acids (FAA) was performed as a ripening index and an indirect measure of flavor development in Swiss-type cheeses. The objective of this research was to assess the effect of warm room treatment (WRT) and usage ratio of starter cultures, Streptococcus thermophilus and Lactobacillus helveticus vs. propionibacteria, on the concentration of FFA and FAA in pilot plant-scale Swiss cheese. A capillary gas chromatograph equipped with a flame ionization detector was used for the analysis of FFA in Swiss cheese. Free amino acids were analyzed by the Cd-ninhydrin method. Starter culture ratios did not affect development of FAA during the cheese ripening. However, duration of WRT had an effect on the concentration of FAA in the Swiss cheese. Free amino acids increased considerably during WRT. A continuous increase in FAA was shown during 70-d ripening time after WRT. The concentrations of C2:0 and C3:0 fatty acids were affected by starter culture ratios after 2-wk WRT, but these differences had mostly disappeared after 3-wk WRT. Similar concentrations of FFA and FAA reported in previous studies were developed in Swiss cheese with a 3-wk WRT and a 0.33:1 ratio of Streptococcus thermophilus and Lactobacillus helveticus to propionibacteria.
对水溶性挥发性游离脂肪酸（FFA）和游离氨基酸（FAA）进行定量分析，以此作为瑞士型奶酪成熟度指标及风味发展的间接衡量标准。本研究的目的是评估暖房处理（WRT）以及嗜热链球菌和瑞士乳杆菌与丙酸杆菌的发酵剂使用比例对中试规模瑞士奶酪中FFA和FAA浓度的影响。配备火焰离子化检测器的毛细管气相色谱仪用于分析瑞士奶酪中的FFA。游离氨基酸采用镉-茚三酮法进行分析。在奶酪成熟过程中，发酵剂比例并未影响FAA的生成。然而，WRT的持续时间对瑞士奶酪中FAA的浓度有影响。在WRT期间，游离氨基酸大幅增加。WRT后70天的成熟时间内，FAA持续增加。WRT两周后，C2:0和C3:0脂肪酸的浓度受发酵剂比例影响，但在WRT三周后，这些差异大多消失。在经过三周WRT且嗜热链球菌和瑞士乳杆菌与丙酸杆菌比例为0.33:1的瑞士奶酪中，FFA和FAA的浓度与先前研究报道的相似。
