Apple flavonoids: isolation and characterization for antioxidant properties in selected food systems

人们对发现天然存在的抗氧化剂作为食品添加剂越来越感兴趣，因为它们有益于保持食品的健康和潜在的健康益处。脂质过氧化是食品中常见的过程，可能导致食品质量下降，并对受影响产品的消费者造成不利的健康问题。一般来说，饮食中的抗氧化剂可以保护体内易受氧化应激影响的分子，如脂质、DNA和蛋白质。除了抗氧化特性，饮食中摄入的多酚类物质，如类黄酮，与人类慢性疾病的发病率呈负相关。苹果是类黄酮的主要食物来源。黄酮类化合物以其清除自由基的特性和对癌症、心脏病和其他慢性疾病的保护能力而闻名。因此，确定苹果类黄酮具有特殊的抗氧化特性，可以防止食物受到氧化损伤，不仅可以替代潜在有毒的合成抗氧化剂，而且还可以通过食用补充了类黄酮的食品来改善人类健康。本研究计划的总体目标是了解苹果及其副产品中特定类黄酮的结构和功能关系，最终目标是开发可商业开发的生物产品，如增值食品配料。本课题将研究超临界流体萃取法提取苹果果皮中黄酮类化合物黄酮醇的技术。离心分配色谱、质谱和核磁共振技术将用于分离和表征特定的黄酮醇。将在选定的实验室、食品和动物模型系统中评估提取物和分离的黄酮醇的抗氧化能力和防止脂质过氧化的能力。反滴定法也将用于消除黄酮醇产生毒性作用的风险。

There is a growing interest in discovering naturally occuring antioxidants as food additives because of their benefits in preserving food wholesomeness and their potential health benefits. Lipid peroxidation is a common process in food that could cause loss of food quality and adverse health problems for the consumers of affected products. In general, dietary antioxidants protect molecules such as lipids, DNA and proteins in the body, which are susceptible to oxidative stress. Beyond the antioxidant properties, intake of dietary polyphenolics such as flavonoids have been inversely associated with incidences of human chronic diseases.  Apples are a major food source of flavonoids. Flavonoids are known for their free radical scavenging properties and protective ability against cancer, heart disease, and other chronic diseases. Therefore, identification of apple flavonoids with specific antioxidant properties that prevent oxidative damage to foods will allow not only for the replacement of potentially toxic synthetic antioxidants but will also improve human health upon the consumption of food products supplemented with flavonoids.      The overall goal of the proposed research program is to understand the structure and function relationship of specific flavonoids present in apple and their by-products with the ultimate goal of developing commercially exploitable bio-products such as value-added food ingredients. This project will investigate health friendly extraction techniques including supercritical fluid extraction to extract flavonols, the predominant group of flavonoids, from apple skin. Centrifugal partition chromatography followed by mass spectrometry and nucleic magnetic resonance techniques will be used to isolate and characterize specific flavonols. The extracts and isolated flavonols will be assessed for their antioxidant capacity and ability to prevent lipid peroxidation in selected laboratory, food, and animal model systems. Counter assays will also be used to eliminate flavonols at risk of producing toxic effects.