Assessment of eggplant freshness using nondestructive techniques

Eggplant fruit is a chilling injury sensitive vegetable, which should be stored at temperature of 12°C; however, at this temperature, the metabolism of the fruit is still intensively active and therefore significant quality deterioration may be induced. Since these quality losses can be difficultly detected by eyes, objective of this study was to develop a novel non-destructive method to estimate freshness of eggplants. Eggplant fruits ('Fantasy') were harvested from a commercial farm in Lecce, Italy, during July 2017. Fruits were stored at 12°C for 10 days. Every 2 days, fruits from were sampled and left at room temperature (20°C), for one additional day, simulating one-day shelf life at the market. Color spectra (360-740 nm), Fourier Transform (FT)-NIR spectra (800-2777 nm) and hyperspectral images (HSI) in the Vis-NIR range (400-1000 nm) were also acquired on each fruit. Partial least square regression analyses were carried out between the data collected and the storage days and appropriate models were built, allowing safe assessment of the freshness of the fruits. According to the results based on whole wavelength ranges, storage days correlated very well with both the FT-NIR spectra and the hyperspectral data extracted from the Vis-NIR imaging system (RC>0.98, RCV>0.94, RMSEC<0.4 and RMSECV<0.8), in contrast to the color measurements with lower RC and RCV values and significantly high root means square errors (1.5 and 1.8, respectively). Moreover, after conducting SPA as a variable selection method, classification models could almost keep the same performance. The results of this study may set the basis to develop a protocol allowing a rapid screening and sorting of eggplants according to their postharvest freshness at distribution center or even upon the reception in the retail market

Improvement of sea fennel (Crithmum maritimum L.) nutritional value through iodine biofortification in a hydroponic floating system

Sea fennel is an herbaceous aromatic and edible halophyte, naturally occurring in coastal areas of the Mediterranean basin. Besides its scientific interest as a salt-tolerant species it exhibits considerable nutritional value and economical potential. As sea fennel is distributed in maritime areas, where natural iodine is available in high concentrations, the aim of this study was to evaluate whether sea fennel has the potential to accumulate elevated iodine concentrations under cultivation. A biofortification experiment in a hydroponic system applying two forms of iodine, KI and KIO3 in different concentrations was set up and monitored using sophisticated targeted elementary and metabolite analysis. The biofortification potential and possible effects on nutritional value were investigated. This study revealed that both iodine forms increased the iodine content of sea fennel tissues. Nutritional and health promoting components, biomass production but also antioxidant potential were stable or even improved under the iodine treatment

Silencing of ascorbate oxidase results in reduced growth, altered ascorbic acid levels and ripening pattern in melon fruit

Ascorbate oxidase (AO, EC 1.10.3.3) is a copper-containing enzyme localized at the apoplast, where it catalyzes the oxidation of ascorbic acid (AA) to dehydroascorbic acid (DHA) via monodehydroascorbic acid (MDHA) intermediate. Despite it has been extensively studied, no biological roles have been definitively ascribed. To understand the role of AO in plant metabolism, fruit growth and physiology, we suppressed AO expression in melon (Cucumis melo L.) fruit. Reduction of AO activity increased AA content in melon fruit, which is the result of repression of AA oxidation and simultaneous induction of certain biosynthetic and recycling genes. As a consequence, ascorbate redox state was altered in the apoplast. Interestingly, transgenic melon fruit displayed increased ethylene production rate coincided with elevated levels of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO, EC 1.14.17.4) activity and gene expression, which might contribute to earlier ripening. Moreover, AO suppressed transgenic melon fruit exhibited a dramatic arrest in fruit growth, due to a simultaneous decrease in fruit cell size and in plasmalemma (PM) ATPase activity. All the above, support for the first time, the in vivo AO participation in the rapid fruit growth of Cucurbitaceae and further suggest an alternative route for AA increase in ripening fruit