Yogurt, a functional dairy food product, is an effective medium for delivering beneficial functional ingredients. One ingredient, γ-aminobutyric acid (GABA), has growing appeal in the development of functional foods for its potential in reducing the risk of diabetes, hypertension, and stress as a bioactive agent. However, the concentration of GABA in existing food products is remarkably low. We developed a functional yogurt rich in GABA using Streptococcus thermophilus fmb5. The GABA yield of yogurt was enhanced by optimization of culture conditions using single factor and response surface methods. The results showed that culture temperature, monosodium glutamate concentration, and culture time are the 3 main factors that affect GABA yield. The optimal culture conditions were determined as follows: 38.8°C for culture temperature, 20 g/L of monosodium glutamate, and 120 h of culture time. Under the above optimal conditions, the actual yield of GABA production was maximized at 9.66 g/L, which was 1.2 times or higher than that of from any single factor treatment. The GABA concentration, viable bacteria number, and water-holding capacity of GABA-rich yogurt were stable throughout the whole storage time. The results show that producing yogurt with Streptococcus thermophilus fmb5 and the optimized culture conditions will achieve high GABA concentrations that maximize health benefits to consumers.

酸奶是一种功能性的乳制品，是传递有益功能成分的有效介质。γ-氨基丁酸（GABA）是一种成分，由于它具有降低糖尿病，高血压和压力作为生物活性剂的风险，因此在功能性食品的开发中具有越来越大的吸引力。但是，现有食品中GABA的浓度非常低。我们使用嗜热链球菌开发了富含GABA的功能性酸奶fmb5。通过使用单因素法和响应面法优化培养条件，可以提高酸奶的GABA产量。结果表明，培养温度，味精浓度和培养时间是影响GABA产量的3个主要因素。确定最佳培养条件如下：培养温度为38.8°C，味精为20 g / L，培养时间为120 h。在上述最佳条件下，GABA的实际产量最高，为9.66 g / L，是任何单因素处理的1.2倍或更高。富含GABA的酸奶中的GABA浓度，活菌数和持水量在整个存储时间内均保持稳定。结果表明，用嗜热链球菌生产酸奶 fmb5和优化的培养条件将实现高GABA浓度，从而最大程度地为消费者带来健康益处。