Mature Red Tomatoes Research Articles

Spatially resolved metabolic distribution for unraveling the physiological change and responses in tomato fruit using matrix-assisted laser desorption/ionization\u2013mass spectrometry imaging (MALDI\u2013MSI)

Information on spatiotemporal metabolic behavior is indispensable for a precise understanding of physiological changes and responses, including those of ripening processes and wounding stress, in fruit, but such information is still limited. Here, we visualized the spatial distribution of metabolites within tissue sections of tomato (Solanum lycopersicum L.) fruit using a matrix-assisted laser desorption/ionization–mass spectrometry imaging (MALDI–MSI) technique combined with a matrix sublimation/recrystallization method. This technique elucidated the unique distribution patterns of more than 30 metabolite-derived ions, including primary and secondary metabolites, simultaneously. To investigate spatiotemporal metabolic alterations during physiological changes at the whole-tissue level, MALDI–MSI was performed using the different ripening phenotypes of mature green and mature red tomato fruits. Although apparent alterations in the localization and intensity of many detected metabolites were not observed between the two tomatoes, the amounts of glutamate and adenosine monophosphate, umami compounds, increased in both mesocarp and locule regions during the ripening process. In contrast, malate, a sour compound, decreased in both regions. MALDI–MSI was also applied to evaluate more local metabolic responses to wounding stress. Accumulations of a glycoalkaloid, tomatine, and a low level of its glycosylated metabolite, esculeoside A, were found in the wound region where cell death had been induced. Their inverse levels were observed in non-wounded regions. Furthermore, the amounts of both compounds differed in the developmental stages. Thus, our MALDI–MSI technique increased the understanding of the physiological changes and responses of tomato fruit through the determination of spatiotemporally resolved metabolic alterations.Graphical abstractᅟ

Shelf-Life and Free Radical Scavenging Activity of Tomato (Lycopersicon Esculentum Mill.) Fruits Coated with Safe Phytochemicals

This study was conducted to investigate the potential of phytochemical extracts on extending the shelf-life of harvested tomato fruits, and to determine which phytochemical extracts can best enhance its shelf-life. The free radical scavenging activity (FRSA) of tomato fruits coated with phytochemical extracts stored under ambient condition and the toxicity of the phytochemical coatings was also evaluated. Mature green, breaker, and mature red tomato (Diamante max hybrid) fruits were used. The fruits were coated with phytochemical extracts derived from starfruit, cat’s whisker, citronella, cocohusk, ginger, and hagimit. The extraction was accomplished using distilled water, ethyl alcohol, and acetic acid. The shelf-life evaluation of the harvested tomato fruits was conducted in a completely randomized design at ambient condition. The results showed that the phytochemical extracts can potentially enhance the shelf-life of harvested tomatoes. The aqueous hagimit extract (AQHE) was able to extend the shelf-life of mature green tomatoes from 44 days to 97 days which is equivalent to 120 % shelf-life enhancement. The ethanolic hagimit extract (ETHE) extended the shelf-life of breaker tomatoes from 27 days to 83 days which is about 207 % shelf-life enhancement. The acetic acid starfruit extract (AASE) extended the shelf-life of mature red tomatoes from 17 days to 31 days which is tantamount to 82 % enhancement of its shelf-life. These findings suggested the potential application of phytochemical extracts to solve the problem of high perishability of vegetables, particularly on tomatoes. The mature red tomatoes gave the highest FRSA among the three maturity stages of tomato tested. However, the FRSA of mature green and breaker tomatoes increased with shelf-life extension. The sustenance of FRSA on coated mature red tomato with extended shelf-life is noteworthy to consider. Furthermore, the acute toxicity tests revealed that these phytochemical coatings are non-toxic and are safe to use as coatings on agricultural products for human consumption.

Free Radical Scavenging Activity of Mature Red Tomato (Lycopersicon esculentum Mill.) Fruit Coated with Hagimit (Ficus minahassae Miq.) Extract

The study was conducted to determine the effect of storage time on the free radical scavenging activity (FRSA) of mature red tomatoes with hagimit extracts, to investigate the effect of timing of application of hagimit extract on the FRSA of the mature red tomatoes, and to evaluate the maximum/optimum FRSA of the mature red tomatoes coated with hagimit extracts. Coating was done on the 4th, 6th and 8th day after harvest of the tomato fruits and analyzed for FRSA. Results show that free radical scavenging activity of untreated tomato fruit drastically reduced after 6 days of storage. However, when the tomato fruits were coated with polar hagimit extracts, the free radical scavenging activity was sustained until 12 days of storage with only gradual decrease until the end of its shelf-life. Application of hagimit extracts 4, 6, and 8 days after harvest of the tomato fruits showed similar preservation of the fruits’ free radical scavenging activity although fruits coated 4 days after harvest were of shorter shelf-life. Moreover, the optimum free radical scavenging activities of tomato fruits coated with aqueous, ethanolic, acetic acid extracts were 340.54, 349.01, 348.88 μmolTE/100g, respectively.

Development of multispectral imaging algorithm for detection of frass on mature red tomatoes

In this research, a multispectral fluorescence-based imaging algorithm was developed to detect frass contamination on mature Campari tomatoes. Tomato images were acquired using a hyperspectral fluorescence line-scan imaging system with violet LED excitation, then analyzed for wavelength selection. The fluorescence intensities at five wavelengths, 515nm, 640nm, 664nm, 690nm, and 724nm, were used to compute three simple ratio functions to detect frass contamination. The contamination spots were created on the tomato surfaces using four low-concentration frass dilutions. The algorithms detected over 99% of the 0.2kg/L and 0.1kg/L frass contamination spots and successfully differentiated these spots from tomato skin surfaces, stem scars, and stems. However, differentiation of the 0.05kg/L and 0.02kg/L frass contamination spots was more difficult. Adjusting the algorithm to successfully detect 95% of the 0.05kg/L spots also resulted in false-positive pixel detections occurring on 28% of the tomatoes. This study demonstrates that a simple multispectral fluorescence imaging algorithm based on violet LED excitation could be useful for rapid postharvest detection of frass contamination on tomatoes in processing lines.

Physicochemical and Sensory Characteristics of Arabic Gum-Coated Tomato (Solanum Lycopersicum L.) Fruits during Storage

The effects of gum arabic surface coating (5–20% aqueous gum solution) on physicochemical and sensory properties of mature red tomato fruits during 16 days of storage at 10 ± 1C were investigated. The firmness of uncoated fruits was significantly (P ≤ 0.05) lower, while weight loss was higher than coated ones. Uncoated tomatoes had higher total soluble solids, low acidity and fluctuating pH values. The values of L and b of the fruits decreased, while that of a increased during storage. The hue angle of the fruits significantly decreased, but total color change significantly increased during storage. The chroma and browning index of fruits increased slightly, while the color index increased significantly. Gum coating showed a better retention of all these physical, chemical and optical parameters of stored tomatoes. Panelists' results showed that gum-coated tomato fruits have acceptable sensory quality. Practical Applications Tomato is an important food commodity from nutritional and commercial point of view; however, freshly harvested tomato fruits have shorter shelf life in the market. Strategies to preserve its physicochemical and sensorial characteristics have significance for grower, processor and seller. We observed that gum arabic coating effectively preserved different quality attributes of tomato fruits for 16 days while stored at even more than normal refrigeration temperature. Our findings are valuable for those involved in tomato fruit handling and processing.

Purification and characterization of β-xylosidase that is active for plant complex type N-glycans from tomato (Solanum lycopersicum): removal of core α1-3 mannosyl residue is prerequisite for hydrolysis of β1-2 xylosyl residue

In this study, we purified and characterized the β-xylosidase involved in the turnover of plant complex type N-glycans to homogeneity from mature red tomatoes. Purified β-xylosidase (β-Xyl'ase Le-1) gave a single band with molecular masses of 67 kDa on SDS-PAGE under a reducing condition and 60 kDa on gelfiltration, indicating that β-Xyl'ase Le-1 has a monomeric structure in plant cells. The N-terminal amino acid could not be identified owing to a chemical modification. When pyridylaminated (PA-) N-glycans were used as substrates, β-Xyl'ase Le-1 showed optimum activity at about pH 5 at 40 °C, suggesting that the enzyme functions in a rather acidic circumstance such as in the vacuole or cell wall. β-Xyl'ase Le-1 hydrolyzed the β1-2 xylosyl residue from Man₁Xyl₁GlcNAc₂-PA, Man₁Xyl₁Fuc₁GlcNAc₂-PA, and Man₂Xyl₁Fuc₁GlcNAc₂-PA, but not that from Man₃Xyl₁GlcNAc₂-PA or Man₃Xyl₁Fuc₁GlcNAc₂-PA, indicating that the α1-3 arm mannosyl residue exerts significant steric hindrance for the access of β-Xyl'ase Le-1 to the xylosyl residue, whereas the α1-3 fucosyl residue exerts little effect. These results suggest that the release of the β1-2 xylosyl residue by β-Xyl'ase Le-1 occurs at least after the removal the α-1,3-mannosyl residue in the core trimannosyl unit.

Predominant Occurrence of Truncated Complex TypeN-Glycans among Glycoproteins in Mature Red Tomato

In this study, we analyzed the structures of complex type N-glycans linked to glycoproteins in mature red tomato to determine the relative ratio of high-mannose type structure and complex type structure. Structural analysis of pyridylaminated N-glycans revealed that the truncated plant complex type structure accounted for about 70% of total conjugated N-glycans, while the high-mannose type structure accounted for about 22%.

α-Mannosidase Involved in Turnover of Plant Complex TypeN-Glycans in Tomato (Lycopersicum esculentum) Fruits

In this study, we purified and characterized an alpha-mannosidase to homogeneity from mature red tomato fruits. Purified alpha-mannosidase (alpha-Man LE-1) gave two separate bands, of molecular masses of 70 kDa (L-subunit) and 47 kDa (S-subunit), on SDS-PAGE under non-reducing and reducing conditions. On the other hand, the molecular weight was estimated to be 230 kDa by gel filtration, indicating that alpha-Man LE-1 functions in a tetrameric structure in plant cells. The N-terminal sequence of the L-subunit and the S-subunit were determined to be L-Y-M-V-Y-M-T-K-Q-G- and X-X-L-E-Q/K-S-F-S-Y-Y respectively. When pyridylaminated N-glycans were used as substrates, alpha-Man LE-1 showed optimum activity at about pH 6 and at 40 degrees C, and the activity was completely inhibited by both swainsonine and 1-deoxy-mannojirimycin. alpha-Man LE-1 hydrolyzed the alpha-mannosidic linkages from both high-mannose type and plant complex type N-glycan, but preferred a truncated plant complex type structure to high-mannose type N-glycans bearing alpha1-2 mannosyl residues.

Culling Tomatoes with External Symptoms of Irregular Ripening Is of Limited Benefit

Mature-green and mature-red tomato (Lycopersicon esculentum Mill.) fruit were harvested from spring- and fall-grown plants infested with sweet potato whitefly (SPWF; Bemisia tabaci Gennadins). The mature-green fruit were either ripened at 20 to 22C or cold-stored at 10 to 13C for 3 weeks and then were allowed to ripen at 20 to 22C. There was no significant difference in the appearance of either external or internal tomato irregular ripening (TIR) symptoms between the two storage–ripening regimes or in the appearance of internal TIR symptoms among the two storage regimes and vine-ripened tomatoes. Thus, removing the tomatoes from the SPWF during ripening does not reduce TIR symptoms. About half of the mature-green tomatoes, ripened with or without cold storage (10 to 13C), developed no external TIR symptoms, but about half of these tomatoes had internal TIR symptoms. About one-third of the tomatoes developed external symptoms during ripening, but these symptoms disappeared after ripening was complete. A high percentage (71%) of these tomatoes with external symptoms also had internal symptoms. The remaining tomatoes developed external TIR that did not disappear, and almost all of these tomatoes had internal symptoms. These data suggest that culling tomatoes that develop external TIR during ripening will reduce but not eliminate tomatoes with internal TIR from the fresh-fruit market.