Postharvest treatment of antioxidant reduces lenticel browning and improves cosmetic appeal of mango (Mangifera indica L.) fruits without impairing quality

Shang

et al. 2020

Preprint

Objective ： Fresh-cut fruits and vegetables is an emerging type of fruits and vegetables processing products for consumers to eat immediately or for the catering industry. Enzymatic browning is one of the crucial problems compromising the flavor and texture of fresh-cut fruit and vegetables. Eggplant is a common vegetable, which is favored by consumers. Accordingly, we used an untargeted metabolomics approach based on liquid chromatography-mass spectrometry (LC-MS) to explore the browning mechanism in peeled eggplant ( Solanum melongena L . ). Results: Metabolomics revealed several hundred differential metabolites, including lipids, phenols, sugars and fatty acids. The content of these metabolites changed dynamically as the peeled time increased. The content of polyphenols, especially chlorogenic acid, increased significantly, suggesting that the main substrate for enzymatic browning in eggplant is chlorogenic acid. Furthermore, all the differential metabolite were mapped to KEGG pathway, revealing significant differences in linoleic acid metabolism, tyrosine metabolism，glutathione metabolism, pentose phosphate pathway, tropane, piperidine and pyridine alkaloid biosynthesis, phenylpropanol metabolism and glycosylphosphatidylinositol(GPI)-anchor biosynthesis over time. Therefore, we speculate that some metabolic pathways that are closely connected with respiration, glycolysis, ATP synthesis, and phenolic synthesi are disturbed after peeling, under the action of enzymes, eventually leading to browning.

Section: Discussionmentioning

confidence: 99%

Metabolomics Study of Browning Mechanism in Eggplant Fruits

Shang

et al. 2020

Preprint

“…The phenolic compounds identified in banana peels in recent years were mainly dopamine, followed by chlorogenic acid and coumarin, with dopaminerase oxidation being the main factor for banana browning 19 . Chlorogenic acid and epicatechin are the phenolic compounds with the highest contents in apple fruits 20 , while the substrates in mango are mainly coffeic acid and ferulic acid 21 . In addition, some studies have shown that apple browning index (BI) is negatively correlated with hyperoside 4 .…”

Section: Discussionmentioning

confidence: 99%

Study on browning mechanism of fresh-cut eggplant (Solanum melongena L.) based on metabolomics, enzymatic assays and gene expression

Shang

et al. 2021

Sci Rep

Enzymatic browning is one of the crucial problems compromising the flavor and texture of fresh-cut fruit and vegetables. In this study, an untargeted metabolomics approach based on liquid chromatography-mass spectrometry (LC–MS) was used to explore the browning mechanism in fresh-cut eggplant. Metabolomics studies showed that with the increase of fresh-cut time, the contents of 946 metabolites changed dynamically. The metabolites having the same trend share common metabolic pathways. As an important browning substrate, the content of chlorogenic acid increased significantly, suggesting that may be more important to fresh-cut eggplant browning; all 119 common differential metabolites in 5 min/CK and 3 min/CK contrastive groups were mapped onto 31 KEGG pathways including phenylpropanol metabolism, glutathione metabolism pathway, et al. In physiological experiments, results showed that the Phenylpropanoid-Metabolism-Related enzymes (PAL, C4H, 4CL) were changed after fresh-cut treatment, the activities of three enzymes increased first and then decreased, and reached the maximum value at 5 min, indicating the accumulation of phenolic substances. At the same time, ROS were accumulated when plant tissue damaged by cutting, the activities of related antioxidant enzymes (SOD, APX and CAT) changed dynamically after oxidative damage. SOD and APX content increased significantly and reached the maximum value at 10 min after cutting, and then showed a downward trend. However, CAT activity increased sharply and reached the maximum value within 3 min after cutting, then maintained the same activity, and showed a downward trend after 30 min. These data fully demonstrated that the activities of browning related enzymes and gene expression increased with the prolonging of fresh cutting time. We explained the browning mechanism of fresh-cut eggplant by combining metabolomics and physiology, which may lay the foundation for better understanding the mechanism of browning during the fruits and vegetables during processing.

“…The phenolic compounds identified in banana peels in recent years were mainly dopamine, followed by chlorogenic acid and coumarin, with dopaminerase oxidation being the main factor for banana browning 36 . Chlorogenic acid and epicatechin are the phenolic compounds with the highest contents in apple fruits 37 , while in caffeic acid and ferulic acid are the main substrates in mangos 38 . Mishra et al .…”

Section: Discussionmentioning

confidence: 99%

Transcriptome profiling reveals potential genes involved in browning of fresh-cut eggplant (Solanum melongena L.)

Zhao³

et al. 2021

Sci Rep

Fresh-cut processing promotes enzymatic browning of fresh fruits and vegetables, which negatively affects the product appearance and impacts their nutrition. We used RNA-sequencing to analyze the transcriptomic changes occurring during the browning of fresh-cut eggplant fruit samples from both browning-sensitive and browning-resistant cultivars to investigate the molecular mechanisms involved in browning. A total of 8347 differentially expressed genes were identified, of which 62 genes were from six gene families (i.e., PPO, PAL, POD, CAT, APX, and GST) potentially associated with enzymatic browning. Furthermore, using qRT-PCR, we verified 231 differentially regulated transcription factors in fresh-cut eggplant fruits. The enzyme activities of PPO, POD, PAL, and CAT in ‘36’ were significantly higher than those of ‘F’ fresh-cut for 15 min. Both PPO and POD play a major role in the browning of eggplant pulp and might therefore act synergistically in the browning process. Meanwhile, qPCR results of 18 browning related genes randomly screened in 15 eggplant materials with different browning tolerance showed variant-specific expression of genes. Lastly, gene regulatory networks were constructed to identify the browning-related genes. This work provides a basis for future molecular studies of eggplants, and lays a theoretical foundation for the development of browning-resistant fresh-cut fruits and vegetables.