Department of Biological Systems Engineering, Washington State University, Pullman, Washington 99163, United States.
J Agric Food Chem. 2011 Aug 10;59(15):8233-43. doi: 10.1021/jf200732p. Epub 2011 Jul 15.
Measuring antioxidant activity using a biologically relevant assay adds important evidence to aid in understanding the role of phytochemicals based on data from in vivo and chemical assays of extrusion processed purple potato and pea flours. A cellular antioxidant activity assay could provide biologically relevant information on bioactive compounds in raw as well as processed food products. The objective of this study was to investigate the complete phytochemical profiles, antioxidant activity, cellular antioxidant activity, and their contribution to bioactivity in purple potato flour, dry pea flour, raw formulations, and extrusion cooked products prepared with the above ingredients. The free fraction of extracts contributed 68, 64, and 88% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in purple potato flour (PPF). Similarly, extracts in the free fraction contributed 87, 86, and 64% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in dry pea flour (DPF). The amount of total phenolics and total flavonoids in purple potato flour and the antioxidant activity of PPF and DPF were comparable to published data. However, a higher amount in the total flavonoids and lower in the total phenolics of DPF were observed. Caffeic, p-coumaric, and ferulic acids were mostly observed in the bound extracts of raw formulations as in the extrudates, whereas chlorogenic acid was predominant in the free extracts. The extruded products had significantly higher (p < 0.05) content of total phenolics, ORAC antioxidant activity, and flavonoids, compared to the raw formulations. Extrusion processing increased the cellular antioxidant activity of the extrudates prepared from 35:65 and 50:50 PPF/DPF (w/w) of ingredients compared with control raw formulations in a dose-dependent manner. Increase of PPF significantly increased (p < 0.05) the cellular antioxidant activity of 35-50% PPF formulations.
使用与生物相关的测定方法来测量抗氧化活性，为理解基于植物化学物质的生物活性提供了重要的证据，这些植物化学物质来自于体内和化学挤压加工紫土豆和豌豆粉的测定。细胞抗氧化活性测定法可以为未加工和加工食品中的生物活性化合物提供与生物相关的信息。本研究的目的是研究完整的植物化学特征、抗氧化活性、细胞抗氧化活性，以及它们对紫土豆粉、干豌豆粉、原始配方和用上述成分制备的挤压蒸煮产品的生物活性的贡献。紫土豆粉（PPF）中提取物的游离部分分别对总酚、总抗氧化活性（ORAC 值）和总类黄酮的总含量贡献了 68%、64%和 88%。同样，干豌豆粉（DPF）中提取物的游离部分分别对总酚、总抗氧化活性（ORAC 值）和总类黄酮的总含量贡献了 87%、86%和 64%。紫土豆粉中的总酚和总类黄酮的含量以及 PPF 和 DPF 的抗氧化活性与已发表的数据相当。然而，DPF 中的总类黄酮含量较高，总酚含量较低。在原始配方和挤压物中，咖啡酸、对香豆酸和阿魏酸主要存在于结合提取物中，而绿原酸则主要存在于游离提取物中。与原始配方相比，挤压产品的总酚、ORAC 抗氧化活性和类黄酮含量显著更高（p < 0.05）。挤压加工增加了由 35:65 和 50:50 PPF/DPF（w/w）成分制备的挤压物的细胞抗氧化活性，与对照原始配方相比，呈剂量依赖性。PPF 含量的增加显著提高了 35-50%PPF 配方的细胞抗氧化活性（p < 0.05）。
