This study aims to determine the priority attributes of nougat with purple sweet potato, cowpea, and stevia leaves, optimize the nougat formulation from the organoleptic aspect, and determine the physicochemical characteristics of nougat. The research method used the Kano model and the central composite design (CCD) response surface methodology (RSM). The results of this study indicate that the attributes that influence consumer satisfaction are purple color, block shape, and low-calorie natural sweeteners. The optimum formulations obtained from purple sweet potato, cowpea, and stevia leaves were 20%, 1.5%, and 0.15% (Formula A14). Nougat products produce a moisture content of 6.09%-7.35%, ash content of 0.73%-1.95%, reducing sugar content of 11.50-17.11%, sucrose content of 35.14-49.38%, total color difference of 38.15-85.40; and hardness 0.357835-10.455 N. All formulations comply with SNI 3547.2-2008 (soft candy not jelly).

中文翻译：

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紫甘薯、豇豆、甜菊叶牛轧糖的配方优化及产品设计分析

本研究旨在确定紫甘薯、豇豆、甜叶菊叶牛轧糖的优先属性，从感官角度优化牛轧糖配方，并确定牛轧糖的理化特性。研究方法采用卡诺模型和中心复合设计（CCD）响应面法（RSM）。这项研究的结果表明，影响消费者满意度的属性是紫色、块状和低热量天然甜味剂。紫甘薯、豇豆、甜菊叶的最佳配方为20%、1.5%、0.15%（配方A14）。牛轧糖产品含水量6.09%-7.35%，灰分0.73%-1.95%，还原糖含量11.50-17.11%，蔗糖含量35.14-49.38%，总色差38.15-85.40；硬度为 0.357835-10.455 N。所有配方均符合 SNI 3547.2-2008（软糖而非果冻）。