Postharvest Quality Evolution in Long Shelf-Life "Vesuviano" Tomato Landrace

"Vesuviano" or "piennolo" tomato is among the most famous Italian small tomato landraces and is cultivated on the slopes of Vesuvio volcano (Southern Italy). The "piennolo" tomato is an interesting case with regard to its potential sustainability, as it is traditionally grown in water-deficit conditions with a low fertilizer input. Fruits with a high firmness and a thick skin can be stored for 3–4 months at room temperature ("long shelf-life" or LSL tomato) without postharvest fungicide applications. The aim of this research was to study the retention, changes in quality, and nutritional traits of "Vesuviano" tomatoes over 120 days of "natural" storage. The dry matter, soluble sugar, organic acids, volatile compounds, and carotenoid contents were evaluated at harvesting and in fruits stored for 40, 80, and 120 days. Slight decreases in dry matter content, soluble sugars, and sweetness index were found, while the organic acids levels remained relatively stable. Moreover, interesting increases in the concentrations of certain flavor volatiles, alcohols, aldehydes, and terpenes were detected. Regarding carotenoids, the total lycopene levels exhibited a 1.5-fold increase from harvest to 120 days. The unchanged lycopene cis-isomer levels and the β-carotene/total lycopene ratio is characteristic of relatively stable isomerization activity and indicated an optimal ripening pattern up until the end of the "natural" storage period. These results, which demonstrate good overall quality retention of this LSL tomato, represent a well-grounded reason to enhance the cultivation and marketing of this genetic resource, the fruits of which can be appreciated by consumers during the winter–early spring, when high-quality fresh tomatoes are not available on the markets

Postharvest Quality Evolution in Long Shelf-Life “Vesuviano” Tomato Landrace

“Vesuviano” or “piennolo” tomato is among the most famous Italian small tomato landraces and is cultivated on the slopes of Vesuvio volcano (Southern Italy). The “piennolo” tomato is an interesting case with regard to its potential sustainability, as it is traditionally grown in water-deficit conditions with a low fertilizer input. Fruits with a high firmness and a thick skin can be stored for 3–4 months at room temperature (“long shelf-life” or LSL tomato) without postharvest fungicide applications. The aim of this research was to study the retention, changes in quality, and nutritional traits of “Vesuviano” tomatoes over 120 days of “natural” storage. The dry matter, soluble sugar, organic acids, volatile compounds, and carotenoid contents were evaluated at harvesting and in fruits stored for 40, 80, and 120 days. Slight decreases in dry matter content, soluble sugars, and sweetness index were found, while the organic acids levels remained relatively stable. Moreover, interesting increases in the concentrations of certain flavor volatiles, alcohols, aldehydes, and terpenes were detected. Regarding carotenoids, the total lycopene levels exhibited a 1.5-fold increase from harvest to 120 days. The unchanged lycopene cis-isomer levels and the β-carotene/total lycopene ratio is characteristic of relatively stable isomerization activity and indicated an optimal ripening pattern up until the end of the “natural” storage period. These results, which demonstrate good overall quality retention of this LSL tomato, represent a well-grounded reason to enhance the cultivation and marketing of this genetic resource, the fruits of which can be appreciated by consumers during the winter–early spring, when high-quality fresh tomatoes are not available on the markets

Effects of preharvest applications of natural antimicrobial products on tomato fruit decay and quality during long-term storage

The effects of preharvest sprays of Thyme essential oil, Propolis and Chitosan on postharvest quality and decay of a \u201clong-storage\u201d tomato, called \u201cVesuviano\u201d, stored at room temperature for 120 days, were investigated. Postharvest fruit quality [number of swollen-healthy fruits (SF), withered-healthy fruits (WF) and rotten fruits (RF)], organoleptic-related indexes (dry matter, soluble sugars, organic acids, volatiles) and health-related compounds (total carotenoids and phenols) were investigated at 40, 80 and 120 days post-harvesting (T40, T80, T120). Propolis and Chitosan were able to reduce rotten fruits starting from T80, while the effect of Thyme was evident as early as T40. Furthermore Chitosan delayed fruit senescence (as expressed by SF/WF ratio) during the long-storage period. All treatments did not affect the overall postharvest quality, nevertheless some compounds (such as total soluble sugar for Chitosan and Thyme; total carotenoids and flavonols for Chitosan; total organic acids, 2-(E)-hexenal, 2-isobutylthiazole and terpenes for Propolis), were better retained than the control during postharvesting period. Among the three natural fungicides, Chitosan was most effective in reducing fruit senescence, maintaining a good quality of the fruits over a long-term

Assessment of Starters of Lactic Acid Bacteria and Killer Yeasts: Selected Strains in Lab-Scale Fermentations of Table Olives (<i>Olea europaea</i> L.) cv. <i>Leccino</i>

Olives debittering, organoleptic quality and safety can be improved with yeasts and lactic acid bacteria (LABs) selected strain starters, that allow for better fermentation control with respect to natural fermentation. Two selected killer yeasts (Wickerhamomyces anomalus and Saccharomyces cerevisiae) and Lactobacillus plantarum strains were tested for olive (cv. Leccino) fermentation to compare different starter combinations and strategies; the aim was to assess their potential in avoiding pretreatments and the use of excessive salt in the brines and preservatives. Lactobacilli, yeasts, molds, Enterobacteriaceae and total aerobic bacteria were detected, as well as pH, soluble sugars, alcohols, organic acids, phenolic compounds, and rheological properties of olives. Sugars were rapidly consumed in the brines and olives; the pH dropped quickly, then rose until neutrality after six months. The oleuropein final levels in olives were unaffected by the treatments. The use of starters did not improve the LABs’ growth nor prevent the growth of Enterobacteriaceae and molds. The growth of undesirable microorganisms could have been induced by the availability of selective carbon source such as mannitol, whose concentration in olive trees rise under drought stress. The possible role of climate change on the quality and safety of fermented foods should be furtherly investigated. The improvement of olives’ nutraceutical value can be induced by yeasts and LABs starters due to the higher production of hydroxytyrosol

Kiwifruit Adaptation to Rising Vapor Pressure Deficit Increases the Risk of Kiwifruit Decline Syndrome Occurrence

Kiwifruit has, for a long time, been widely affected by a syndrome named &ldquo;kiwifruit decline syndrome&rdquo; (KiDS). Several environmental factors have already been investigated looking for the possible origin of this syndrome. Recently, a possible role of climate change has been proposed, highlighting the influence of high air and soil temperature. In this work, the role of rising vapor pressure deficit (VPD) was also investigated in an experimental orchard in which several agronomic practices were examined in order to find strategies to face KiDS occurrence in crops. Stomatal control in response to rising VPD showed to be lacking, and root xylem vessel size and number modifications were observed as an adaptation to water stress; then, a scarce prospect of success facing sudden and strong weather events related to climate change can be expected in this plant. None of the agronomic strategies tested, that were focused on the soil quality improvement and on prevention of desiccation, avoided the KiDS occurrence. Agronomic management should move to new practices focused on orchard climate control

Mercaptosilane-Passivated CuInS2 Quantum Dots for Luminescence Thermometry and Luminescent Labels

Bright and nontoxic quantum dots (QDs) are highly desirable in a variety of applications, from solid-state devices to luminescent probes in assays. However, the processability of these species is often curbed by their surface chemistry, which limits their dispersibility in selected solvents. This renders a surface modification step often mandatory to make the QDs compatible with the solvent of interest. Here, we present a new synthetic approach to produce CuInS2 QDs compatible with organic polar solvents and readily usable for the preparation of composite materials. 3-Mercaptopropyl trimethoxysilane (MPTS) was used simultaneously as solvent, sulfur source, and capping agent for the QD synthesis. The synthesized QDs possessed a maximum photoluminescence quantum yield around 6%, reaching approximately 55% after growing a ZnS shell. The partial condensation of MPTS molecules on the surface of QDs was probed by solid-state nuclear magnetic resonance, whose results were used to interpret the interaction of the QDs with different solvents. To prove the versatility of the developed QDs, imparted by the thiolated silane molecules, we prepared via straightforward procedures two nanocomposites of practical interest: (i) silica nanoparticles decorated with QDs and (ii) an inexpensive polymeric film with embedded QDs. We further demonstrate the potential of this composite film as a luminescence thermometer operational over a broad temperature interval, with relative thermal sensitivity above 1% K−1 in the range of biological interest