UMR408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, F-84000 Avignon, France.
J Agric Food Chem. 2012 Apr 11;60(14):3551-63. doi: 10.1021/jf204785w. Epub 2012 Mar 29.
The objectives of this study were (i) to test different conditions of freezing, thawing, and grinding during sample preparation and (ii) to evaluate the possibility of using mid-infrared spectroscopy for analyzing the composition of sugars, organic acids, and polyphenols in apples. Seven commercial apple cultivars were chosen for their large variability in composition (total polyphenols from 406 to 1033 mg kg(-1) fresh weight). The different conditions of sample preparation affected only the phenolic compounds and not sugars or organic acids. The regression models of the mid-infrared spectra showed a good ability to estimate sugar and organic acid contents (R(2) ≥ 0.96), except for citric acid. Good predictions were obtained for total phenolic, flavan-3-ols, and procyanidins (R(2) ≥ 0.94) provided oxidation was avoided during sample preparation. A rapid and simple procedure was then proposed for phenolic compounds using sodium fluoride during sample homogenization at ambient temperature and freeze-drying before spectra acquisition.
(i) 测试在样品制备过程中不同的冷冻、解冻和研磨条件；(ii) 评估中红外光谱法用于分析苹果中糖、有机酸和多酚成分的可能性。选择 7 个商业苹果品种，其成分差异很大（总多酚含量从 406 到 1033 mg kg(-1) 鲜重）。样品制备条件的不同仅影响酚类化合物，而不影响糖或有机酸。中红外光谱的回归模型显示出很好的估计糖和有机酸含量的能力（R(2) ≥ 0.96），除了柠檬酸。如果在样品制备过程中避免氧化，则可获得总酚、黄烷-3-醇和原花青素的良好预测值（R(2) ≥ 0.94）。然后提出了一种快速简便的方法，即在室温下使用氟化钠进行样品均化，并在光谱采集前进行冷冻干燥，用于酚类化合物。
