Betalains are pigments highly appreciated in the food industry for their applications for human consumption and for their different contributions to human health. However, the stability of betalains is compromised by several factors, including temperature and pH, so it is necessary to determine the optimal conditions to maintain the betalains stability in the final product. In this study, different protocols for extracting betalains from amaranth are compared, and Attenuated Total Reflectance-Fourier Transformation Spectroscopy (ATR-FTIR) together with principal component analysis (PCA) is used to determine amaranth pigments stability at different temperatures and pHs. A simple and efficient method to extract betalains from amaranth plants was established. It was possible to know the stability of amaranth betalains under different temperatures and pH conditions using ATR-FTIR and UV/Vis spectroscopy. The bands associated with carboxylic acids, amino groups, carbon dioxide and carbon double bonds detected by ATR-FTIR spectroscopy were related to the state of conservation and degradation of betalains. Our results will improve the storage, supervision and application of betalains in the food industry.

甜菜红素是食品工业中备受推崇的色素，因其可用于人类消费以及对人类健康的不同贡献。然而，甜菜红素的稳定性受到多种因素的影响，包括温度和 pH 值，因此有必要确定维持最终产品中甜菜红素稳定性的最佳条件。在这项研究中，比较了从苋菜中提取甜菜红素的不同方案，并使用衰减全反射傅立叶变换光谱 (ATR-FTIR) 和主成分分析 (PCA) 来确定苋菜色素在不同温度和 pH 下的稳定性。建立了一种简单、高效的从苋菜植物中提取甜菜碱的方法。利用 ATR-FTIR 和 UV/Vis 光谱可以了解苋菜甜菜碱在不同温度和 pH 条件下的稳定性。ATR-FTIR 光谱检测到的与羧酸、氨基、二氧化碳和碳双键相关的谱带与甜菜碱的保存和降解状态有关。我们的研究结果将改善甜菜碱在食品工业中的储存、监管和应用。