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BACKGROUND: 'Vegetative' and 'generative' tomato rootstock types have been proposed based on their different effects on tomato scion growth performance; however, their impacts on fruit quality have not been characterized. No study has been conducted in which the effects of rootstock on grape tomato quality attributes were assessed using sensory and instrumental methods of evaluation. Here, we conducted two experiments to examine the influence of 'DR0141TX', 'Estamino', and 'Multifort' rootstocks (vegetative, generative, and uncharacterized, respectively) on fruit quality properties of determinate and indeterminate grape tomato scions under organic production in high tunnels, including color, size, firmness, dry matter content, soluble solids content (SSC), titratable acidity (TA), pH, and consumer sensory attributes. RESULTS: In both experiments, grafting 'Sweet Hearts' indeterminate grape tomato onto 'DR0141TX', 'Estamino', or 'Multifort' increased fruit size and led to negligible effects on sensory attributes and instrumental measurements of fruit quality attributes. For 'BHN 1022' determinate grape tomato, rootstocks did not exhibit any major impact on fruit quality attributes in Experiment 1. However, fruit quality was compromised by grafting per se and rootstocks, especially 'Multifort', in Experiment 2, as reflected by reduced SSC, TA, and SSC/TA and lower scores for overall appearance, overall acceptability, tomato flavor, overall texture, and sweetness. CONCLUSION: In general, 'vegetative' and 'generative' rootstocks showed comparable effects on sensory evaluations and instrumental measurements of grape tomato quality attributes for both indeterminate and determinate scions. More research is needed to better characterize rootstock effects on fruit quality, including the flavor‐related compounds under different growing conditions. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Reducing the negative effects of chilling injury (CI) in tomatoes after harvest is essential to ensure good quality and to minimize losses. CI is a postharvest disorder associated with the generation of reactive oxygen species (ROS) in the fruit. Therefore, antioxidant accumulation can counteract ROS, alleviating CI symptoms. In this sense, it has been confirmed that a brief hot‐water (HW) immersion promotes the synthesis of antioxidants. RESULTS: HW treatment at 52 °C for 5 min significantly reduced chilling‐associated decay, from 66.7% to 17.2% in breaker turning (BT) and from 55.8% to 9.8% in mature green (MG) 'BHN‐602' tomatoes stored at 5 °C for 2 weeks and from 26.7% to 6.7% in BT tomatoes stored at 5 °C for 1 week. Also, HW treatment significantly increased lycopene content by 17% in BT tomatoes stored at 5 °C for 2 weeks, as well as ascorbic acid by 11%, lipophilic phenolics by 18% and total phenolics by 6.5% in BT tomatoes stored at 12.5 °C for 1 week. Despite the increase of antioxidants, HW treatment did not enhance the sensory aromatic profile, color and antioxidant capacity. Interestingly, HW treatment reduced ripening time by 3 days in MG tomatoes stored at 5 °C for 2 weeks or at 12.5 °C for 1 week. CONCLUSION: HW treatment applied to MG or BT 'BHN‐602' tomatoes can alleviate the development of some CI symptoms, particularly decay, possibly by increasing antioxidants that scavenge ROS. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Designing modified atmosphere packages (MAPs) for fresh produce requires respiration rate (RR) data. A steady‐state (SS) approach is widely used but is expensive, tedious, and time‐consuming. Unsteady‐state (USS) methods mitigate shortcomings of the SS approach, but comparisons between the two approaches have not been done to verify the design outcomes of MAPs, especially those with microperforations. RR measurement methods for grape tomatoes and blueberries were compared. Data were then used to design microperforated MAP packages to compare predicted design specifications created from RR data with observed shelf life. Results show that the USS method provides similar magnitudes of RR and predicts similar numbers of perforations as the SS method. Observations of packages produced using 100 µm perforations, using measured respiration data, suggest that both methods underestimated what might have been deemed correct by about one microperforation. Practical Application: Designing packaging for fresh produce requires the knowledge of produce respiration. Steady‐state methods are conceptually simple, but time‐consuming. Unsteady‐state methods are rapid. This work compares methods on design of packages. [ABSTRACT FROM AUTHOR]

“Rhapsody” tomatoes were not heated or heated in air at 34 or 38C and 95% relative humidity (RH) for 24 h then stored at 4 or 20C for up to 4 weeks. The fruits were severely injured by 38C exposure, while those heated at 34C were only slightly injured. Heated fruit had more weight loss than control fruit. Nonheated fruit and those heated at 34C developed the best color compared with fruit heated at 38C. There were no differences in chlorophyll degradation between heated and nonheated fruit stored at 4C; however, fruits that were not heated and stored at 20C were the only ones with chlorophyll that degraded completely. Fruit stored at 20C developed a high quantity of lycopene andβ -carotene, with the highest level obtained in fruit heated at 34C and stored at 20C. Fruit stored at 4C almost did not develop any carotenoids. [ABSTRACT FROM AUTHOR]

Recently, so-called “vegetative” and “generative” rootstocks have been identified by seed companies as rootstock types that have different impacts on tomato scions. In this experiment of grafted grape tomato production in an organically managed high tunnel system, we characterized the effects of vegetative and generative rootstock cultivars on tomato yield components and fruit mineral contents. Grape tomato scions ‘BHN 1022’ (determinate) and ‘Sweet Hearts’ (indeterminate) were grafted onto ‘DR0141TX’ (vegetative), ‘Estamino’ (generative), and ‘Multifort’ (noncharacterized) rootstocks with self- and nongrafted scions as controls. Experiments were conducted twice with different transplanting dates (Expt. 1: 31 Jan. vs. Expt. 2: 9 Mar.) in 2018. No rootstock by scion interaction effects on whole-season fruit yield components were observed, indicating similar responses of determinate and indeterminate grape tomato scions to all rootstocks tested. For Expt. 1, the three rootstocks increased marketable fruit number, marketable yield, and total yield by 23.3%, 37.9%, and 34.4% on average, respectively, compared with the self- and nongrafted controls, primarily due to improved productivity during the peak and late harvest periods. For Expt. 2, the rootstocks did not significantly benefit any whole-season yield components. ‘DR0141TX’ and ‘Multifort’ increased stem diameter in both experiments, whereas ‘Estamino’ only increased stem diameter in Expt. 2 relative to the nongrafted controls. Consistent increase in aboveground dry biomass of rootstock treatments at crop termination in Expt. 1 corresponded to the greater yield of rootstock-grafted plants in that experiment. All rootstocks in both experiments consistently increased fruit P, K, Ca, Zn, and Fe contents on a dry weight basis at peak harvest regardless of the tomato scion used. Despite a relatively low level of root-knot nematode infestation, plants grafted with ‘DR0141TX’ or ‘Estamino’ tended to have lower root galling index ratings than scion controls and ‘Multifort’-grafted plants, which was more evident in Expt. 1. Given the different environmental conditions during the tomato production period between the two experiments conducted in high tunnels, our findings highlight the important influence of production environment on grafted tomato performance. This study on grafted grape tomatoes in high tunnel organic production systems also demonstrated that so-called “vegetative” and “generative” rootstocks had similar impacts on tomato scion yield components and fruit mineral contents. [ABSTRACT FROM AUTHOR]

• A HW applied on MG tomatoes induced higher antioxidant capacity when ripe. • High-temperature ethylene treatment promoted phenolics compounds. • HW synergized with high temperature ethylene treatment to promote antioxidants. • High temperature ethylene treatment delayed ripening of tomatoes. Controlled postharvest stresses were used to induce the synthesis of antioxidants in tomato fruit. In this study, a hot-water (HW) treatment of 52 °C for 5 min promoted higher total oxygen radical absorbance capacity (ORAC) compared to fruit immersed in 25 °C water for 5 min. Whereas, ethylene treatment at high temperature, particularly at 35 °C for 24, 48 or 72 h, induced higher content of total phenolics and ferric reducing ability of plasma (FRAP) than fruit treated with ethylene at 20 or 30 °C. In combination, there was synergy between the treatments, and this was most notable by the increase of total phenolics in HW-treated tomatoes exposed to ethylene at 35 °C for 24, 48 or 72 h. There was also a significant increase of total ORAC in HW-treated fruit exposed to ethylene at 30 °C for 72 h or 35 °C for 24, 48 or 72 h. This increase in antioxidant capacity was observed in the hydrophilic fraction of HW-treated fruit exposed to ethylene at 30 °C for 72 h or 35 °C for 24 or 48 h and in the lipophilic fraction of HW-treated tomatoes exposed to ethylene at 35 °C for 24, 48 or 72 h. Moreover, The HW-treatment especially maintained the level of total carotenoids and ascorbic acid when exposed to ethylene at 30 °C for 72 h or 35 °C for 48 or 72 h. Nevertheless, the high temperature ethylene treatment reduced the a* value of tomato peel regardless of the application of HW treatment. In conclusion, application of a HW treatment of 52 °C for 5 min followed by exposure to ethylene at 35 °C for 48 h was most effective in synergistically improving the antioxidant capacity and composition of tomatoes without severely impairing color development. [ABSTRACT FROM AUTHOR]

The U.S. fresh-market tomato industry faces increasing competition from Mexico, which achieves greater productivity and quality due to the use of protected structures. Protected agriculture is limited in humid, subtropical regions of the United States. Although grower interest in high tunnel production has increased in recent years, systematic high tunnel research has not yet been conducted in subtropical Florida. Additionally, although tomato grafting has shown the potential to overcome biotic and abiotic stresses, research of high-tunnel, grafted tomato production in subtropical conditions is lacking. During this 2-year study (Citra, FL), a side-by-side comparison of open field and high tunnel organic tomato production was conducted using a split-split plot design. The most significant benefit of high tunnel production was season extension achieved through the reduction of foliar disease severity, which reduced the area under the disease progress curve by 64% across two seasons. This may be largely attributed to the pronounced reduction in the duration of leaf wetness during the wet months of the growing cycle. Grafting with 'Multifort' rootstock reduced the root-knot nematode soil population density by 88% as well as root galling severity, both of which demonstrated the potential for increased levels in the high tunnel production system compared with open field production. The more severe root-knot nematode infestation in high tunnels was likely due to the modification of soil temperatures, which were 2 8C greater during the early part of the season but were reduced after shadecloth application. Compared with the open field, solar radiation was reduced by 23% in the high tunnel before shadecloth application and by 51% after shadecloth application; however, due to the high radiation levels in subtropical Florida, daily light integral levels indicated that light was not limiting for high-quality tomato production. The average wind speed was reduced by 57% in the high tunnel and, together with the reduction in solar radiation, indicated the potential reduction in summer abiotic stress and evapotranspiration within high tunnels. These results revealed that the integrated use of high tunnel and grafting technologies may be important for enhancing fresh-market tomato production in the humid subtropics, especially in organic systems. [ABSTRACT FROM AUTHOR]

Harvesting before ripening initiation (i.e., mature green) may negatively affect the flavor of fresh tomatoes (Solanum lycopersicum) even though the ripening process off the vine is physiologically the same as that on the plant. Low temperature storage at or below the putative chilling injury (CI) threshold can also have detrimental effects on fresh tomato flavor regardless of the developmental stage of the fruit at harvest, but sensitivity to CI declines with ripening. Controlled atmospheres (CA) using reduced oxygen and elevated carbon dioxide partial pressures can extend the shelf life (SL) of tomatoes while possibly minimizing the negative effects of low temperatures. In this study, we explored the possibility that a combination of temperature and CA could be used to achieve similar SL for pink-harvested tomatoes as has been found in other studies with green-harvested fruit while avoiding the negative effects of CI on sensory quality. Consumer panels were given samples of pink-harvested tomatoes after they had reached the red ripeness stage in terms of surface hue following storage for 7 days in air or CA at 7.5, 15, or 20 °C followed by 2-7 days ripening in air at 20 °C. Exposing pink tomatoes to 7.5 °C before ripening to the full-red stage at 20 °C negatively affected fruit sensory quality, holding fruit constantly at 20 °C until they reached the full-red stage resulted in better quality for one taste panel, whereas there was no difference in another taste panel. The time to reach the full-red stage was extended by CA. Sensory quality of air- and CAstored fruit was similar at the nonchilling temperatures of 15 and 20 °C. Pink stage tomato fruit stored in CA at 7.5 °C for 7 days did not attain full red color within the subsequent 7 days in air at 20 °C. [ABSTRACT FROM AUTHOR]

Abstract: ‘Rhapsody’ tomatoes heated for 24h in air at 34 or 38°C were compared to fruit heated in 5% O2 at 38°C in order to determine if heat treatment applied in reduced O2 pressure might reduce stress-related oxidative changes that sometimes accompany heat injury. Fruit were subsequently stored at 4 or 10°C for up to 30d. Unheated fruit and those heated in air at 34°C for 24h developed the best colour during storage at 10°C. Storage at 4°C inhibited carotenoid development in all treatments. Fruit heated in air or in 5% O2 lost the most ascorbic acid and isoascorbic acid. Glutathione reductase activity at the end of storage was similar in all fruit, while glutathione S-transferase activity was higher in fruit that had initially been heated in 5% O2. Heating of ‘Rhapsody’ tomato fruit in air at 34°C for 24h prior to storage at 10°C for up to 30d resulted in the least losses in antioxidant content, and fruit colour developed adequately. Reduced O2 neither improved the efficacy of the heat treatment in reducing chilling injury nor protected tomato fruit from the negative effects of heat treatment. [Copyright &y& Elsevier]

Abstract: Hexanal, Z-3-hexenal, E-2-hexenal, hexanol, and Z-3-hexenol are major tomato (Solanum lycopersicum L.) volatile aroma compounds derived from oxygenation of unsaturated fatty acids. Chilling and heating may suppress production of these C6 volatiles. The objective of this research was to determine the effects of chilling or heating on gene expression and enzyme activity of lipoxygenase (LOX), hydroperoxide lyase (HPL), and alcohol dehydrogenase (ADH), which catalyze key steps in C6 volatile production via the oxylipin pathway. ‘Tasti-Lee’ and ‘Sanibel’ tomatoes, harvested at different stages of fruit development, were ripened to full (red) ripe stage at 20°C. Fruit were then treated by either chilling (5°C for 5d) or heating (52°C hot water for 15min), then cooled with 23°C tap water to 25°C and placed at 20°C for 4d, or held continuously at 20°C as the control. Both chilling and heating reduced C6 aldehyde and alcohol aroma volatiles immediately after treatment, and the levels of aldehydes did not fully recover after 4d at 20°C. Chilling down-regulated expression of TomloxA, B, and C, but not D; however, it increased total LOX activity. Chilling also down-regulated HPL and ADH expression immediately after treatment, but, after 4d at 20°C, both genes were up-regulated compared to the control. HPL activity in chilled tomatoes was reduced, but recovered to control levels after 4d at 20°C. ADH activity in chilled fruit decreased after 4d at 20°C. On the other hand, heating greatly up-regulated TomloxB and C expression, even after 4d at 20°C, and slightly down-regulated TomloxA and D, while increasing overall LOX activity. Heating up-regulated both HPL and ADH, and that effect persisted for 4d at 20°C. However, heating reduced the activities of HPL for 4d at 20°C and ADH immediately after treatment. The results indicate that heating and chilling regulate C6 volatile production by different mechanisms. Chilling-induced inhibition of C6 volatile production may be due to down-regulation of gene expression, and subsequent reduction of HPL and ADH enzyme activities in the oxylipin pathway. Heating-inhibition of C6 volatile production, however, does not appear to be due to down-regulation of gene expression, but HPL and ADH activities were briefly suppressed. [Copyright &y& Elsevier]