Symbolic Metabolite Analysis of Pickled Wax Gourd in Eastern China by ¹H-NMR Spectroscopy and Multivariate Data

Abstract

Pickled wax gourd is a traditional fermented vegetable product popular in Zhejiang province, eastern China; however, information on their quality is quite limited. In the present study, we investigated the quality of pickled wax gourd at different processing phases using nuclear magnetic resonance, principal component analysis, and orthogonal partial least squares-discriminant analysis. According to the spectra of 1 H NMR, 36 kinds of metabolites were found at the 20th day of fermentation. Principal component analysis score plot showed that diverse marker metabolites occurred in all designated sampling points (every other 5 days), apart from the samples between the 10th day and 15th day of fermentation. Symbolic metabolites at the first 5 days were L-rhamnose, lactate, fatty acid, arginine, N-acetylglutamate, succinate, phosphorylcholine, glutamate, ornithine, lysine, and β-glucose. Lactate, succinate, glycine, proline, and choline were detected at the following period from the 5th to the 10th day of fermentation. Lactate, succinate, glycine, mannitol, choline, and α-ketoglutaric acid were the main metabolites on the 15th and 20th day. The diversity of metabolites fits with the microbial species structure in different pickling periods. This method was proved to be effective for monitoring the pickling process in real time.

Microbiota Succession and Chemical Composition Involved in the Radish Fermentation Process in Different Containers

“…Although ketoglutaric acid has previously been found in pickled wax gourd (Wu et al, 2016), its concentration was low in the samples of this study. Although butyric acid may be associated with the spoilage of fermented cucumbers (Medina et al, 2016), and was not found in the samples from any of the containers on the 6th day, it was evident in low concentrations in all containers on the 12th day.…”

The Changes in Endogenous Metabolites in Hyperlipidemic Rats Treated with Herbal Mixture Containing Lemon, Apple Cider, Garlic, Ginger, and Honey

“…The conventional analytical instruments for the detection are mass spectrophotometer (MS) or nuclear magnetic resonance (NMR). NMR metabolomics has been successfully applied in analyzing complex sample matrices in food chemistry, toxicology and environmental studies [ 19 , 20 ]. It is also being used in the medicinal and pharmacological fields in detecting putative biomarkers, especially biomarkers related to the pathogenesis of the disease and testing for a new lead compound [ 19 ].…”

“…NMR metabolomics has been successfully applied in analyzing complex sample matrices in food chemistry, toxicology and environmental studies [ 19 , 20 ]. It is also being used in the medicinal and pharmacological fields in detecting putative biomarkers, especially biomarkers related to the pathogenesis of the disease and testing for a new lead compound [ 19 ]. The information generated from these data can help clinicians and researchers understand the efficacy of the treatment of the disease.…”

Effect of Different Drying Treatments and Solvent Ratios on Phytochemical Constituents of Ipomoea aquatica and Correlation with α-Glucosidase Inhibitory Activity

“…[20,21] In recent years, it has been widely used in several fields, such as agriculture, food chemistry, toxicology, and medicine. [22,23] A lot of high throughput metabolomics methodologies are currently available, and among them, proton nuclear magnetic resonance ( 1 H NMR) is more preferred due its robustness, reproducibility, and nondestructiveness. [20,24] The 1 H-NMR is an emerging leading analytical tool in metabolomics studies due to a large number of identified compounds.…”