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Processing Techniques and Production Systems on Phytochemical Properties in Fruits Vegetables and Their Processed Products
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Fruits and vegetables contain substantial amounts of phytochemicals that play crucial roles in the prevention of several chronic diseases. However, there is a general lack of insight among the researchers regarding the impacts of processing techniques, diversity among varieties, and other similar such factors on the overall metabolic profiles of these fruits and vegetables. The recent use of advanced metabolomic approaches in assistance with powerful statistical tools to characterize the entire metabolic composition has been gaining significant momentum in the areas of food science. In the first study, comprehensive metabolomics was combined with chemometric approaches to evaluate the impact of processing techniques on the physiochemical attributes, phytochemical contents and antioxidant activities of 21 commonly consumed vegetables. The results suggested that the purple baby carrot blended juice had the highest total phenolics and DPPH value. Principal component analysis (PCA) and partial least squares discriminant analysis (PLSDA) characterized kaempferol glycosides and betaxanthins attached with amino acids, which, were significantly affected by the processing techniques. In the second study, the chemometric characterization of 30 commercial thermal and cold pressed juices were investigated. Significant variations were observed for metabolic compositions in juices with diverse ingredients. Kaempferol and quercetin glycosides, decarboxylated betalains, and quercetin derivatives were found to be the representative metabolites in classifying the samples. In the third study, the solvent extract efficiency and antioxidant activities in conventionally- and organically-grown beets (red and golden colored) were assessed by using a comprehensive range of solvents. The results demonstrated that red beet extracted with methanol with or without ascorbic acid had the highest betanins, while the water-based extracts had the lowest betanins. Golden colored beet extracted with methanol: ascorbic acid: water (18:80:2, v/v/v) had the highest vulgaxanthin I. Meanwhile, the Ultra-high- performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOFMS) identified 25 phytochemicals in conventional red-, 20 in organic red-, 6 in conventional golden-, and 6 in organic golden-colored beet extracts, respectively. In summary, these results highlight the potential of metabolomic approaches in phytochemical profiling of vegetables grown under diverse production systems and their juices processed through different techniques.
Wang, Junyi (2019). Processing Techniques and Production Systems on Phytochemical Properties in Fruits Vegetables and Their Processed Products. Master's thesis, Texas A&M University. Available electronically from