Abstract In this study, 360 intact almonds, half sweet and half bitter, were assessed by near-infrared (NIR) spectroscopy to predict amygdalin content (established by high performance liquid chromatography (HPLC)) and by applying partial least squares (PLS) to the spectral data. After optimising amygdalin extraction and chromatographic conditions, the amygdalin contents found by HPLC were not detected or below to 350 mg kg−1 for sweet almonds, and between 14,700 and 50,400 mg kg−1 for bitter almonds. The intact almond spectra resulted in good predictions of amygdalin content with R2p of 0.939 and RMSEP of 0.373. Almonds were correctly classified into sweet and bitter by linear discriminant analysis (LDA), quadratic discriminant analysis (QDA) and PLS-DA, with sensitivity and specificity values higher than 0.94 for evaluation set samples. Based on these results, it can be concluded that NIR spectroscopy is a good non-destructive alternative to be used as an automatic in-line classification system by food industry.

中文翻译：

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NIR 光谱预测完整杏仁中 HPLC 中苦杏仁苷含量的潜力和基于杏仁苦味的分类

摘要 在这项研究中，通过近红外 (NIR) 光谱法评估了 360 个半甜半苦的完整杏仁，以预测苦杏仁苷含量（由高效液相色谱 (HPLC) 确定），并通过应用偏最小二乘法 (PLS) 来预测苦杏仁苷含量。光谱数据。优化苦杏仁苷提取和色谱条件后，HPLC 检测到的苦杏仁苷含量未检出或低于 350 mg kg-1 甜杏仁，14,700 至 50,400 mg kg-1 苦杏仁。完整的杏仁光谱可以很好地预测苦杏仁苷含量，R2p 为 0.939，RMSEP 为 0.373。通过线性判别分析（LDA）、二次判别分析（QDA）和PLS-DA将杏仁正确分类为甜和苦，评价集样本的敏感性和特异性值均高于0.94。