Red Ripe Tomato Research Articles

PENGUNAAN EKSTRAK TOMAT SEBAGAI INOVASI PAKAN ALAMI UNTUK MENINGKATKAN KUALITAS WARNA IKAN BADUT MERAH MARUN (Amphiprion biaculeatus, Bloch 1790)

Background: Amphiprion biaculeatus, Bloch 1790 is one of the exported marine ornamental fish commodities. To meet export demand, must be from cultivation fish. However, the problem faced in cultivation conditions is that the color of the fish is not as attractive as in nature. This is due to uniform feeding. Therefore, alternative solutions are needed to enrich feed with natural pigment sources. One of them is red ripe tomato extract with high carotene content. Methods: The study used a completely randomized design with extract concentration treatments (0, 25%, 50%, 75%). Natural feed is made by coating, then applied to non-breeder sized fish obtained from BPBL Ambon. Extract efficiency parameters were measured through color characteristics, carotene content in the skin and fins, total length and body weight. The data obtained were analyzed using ANOVA and continued with the DMRT test at a significance level of 95%. Results: The results showed that tomato extract had a significant effect on color characteristics, carotenoid content, total length and body weight in maroon clownfish. The concentration of tomato extract which had the highest value for all parameters measured was in treatment 75% : 75 mL tomato extract + 10 mL binder + 15 g commercial feed). Conclusion: Tomato extract has the potential as a natural feed that can improve the color quality of A. biaculeatus with a usable concentration of 75%.

Neural Network-Based Image Processing for Tomato Harvesting Robot

Agriculture is one of the areas that can benefit from robotics technology, as it faces issues such as a shortage of human labor and access to less arid terrain. Harvesting is an important step in agriculture since workers are required to work around the clock. The red ripe tomatoes should go to the nearest market, while the greenest should go to the farthest market. Harvesting robots can benefit from Neural Network-based image processing to ensure robust detection. The vision system should assist the mobility system in moving precisely and at the appropriate speed. The design and implementation of a harvesting robot are described in this study. The efficiency of the proposed strategy is tested by picking red-ripened tomatoes while leaving the yellowish ones out of the experimental test bed. The experiment results demonstrate that the effectiveness of the proposed method in harvesting the right tomatoes is 80%.

Studies on postharvest loss assessment of Tomato fruits using Aloe Vera gel as mitigating agent

This work evaluates effect of aloe gel coatings on post-harvest quality management of red ripe tomato fruits. Red ripe tomato fruits were purchased from Mandate market, Ilorin, Kwara State. It was sorted and washed with potable water. The sample was divided into four (4) lots for dip treatment in already prepared different aloe vera solutions and labelled: A0 (control), A1 (1.5% aloe vera), A2 (50% aloe vera) and A3 (100% aloe Vera). The pre-treated lots were stored on a laboratory shelf at ambient for 15 days. Physicochemical and nutritional properties were evaluated using standard procedures. Moisture (97.58%) and ash contents (0.68%) of lot A3 (100% aloe gel) were significantly higher (p<0.05) than the other lots. Results showed that lot A1 had the lowest weight loss of 13.1%, while A3 recorded the highest (37.2%). Lot A1 had significantly (p<0.05) higher sensory attributes than the other lots. At day 15, TTA was between 0.13 and 0.35 %, with lot A1 recording significantly (p<0.05) higher value of 0.35 %. TSS content of the tomato fruits decreased with increase in storage with exception to lot A2 which had the highest value (5.30 oBrix). There was a decrease in pH value of both the untreated and treated lots. The results also showed that the vitamin C content of the stored tomato fruits increased significantly (p<0.05) in all the lots as storage days progressed. The result from the study showed that Lot A1 retarded water loss and delayed fruit softening thereby making them acceptable to consumer.

Molecular Responses of Red Ripe Tomato Fruit to Copper Deficiency Stress.

Fruit nutritional value, plant growth, and yield can be compromised by deficient copper (Cu) bioavailability, which often appears in arable lands. This condition causes low Cu content and modifications in the ripening-associated processes in tomato fruit. This research studies the transcriptomic changes that occur in red ripe tomato fruit grown under suboptimal Cu conditions to shed light on the molecular mechanisms underlying this stress. Comparative RNA-sequencing and functional analyses revealed that Cu deficiency during cultivation activates signals for metal ion transport, cellular redox homeostasis, pyridoxal phosphate binding, and amino acid metabolism while repressing the response to phosphate starvation in harvested fruit. Transcriptomic analyses highlighted a number of novel Cu stress-responsive genes of unknown function and indicated that Cu homeostasis regulation in tomato fruit may involve additional components than those described in model plants. It also studied the regulation of high-affinity Cu transporters and a number of well-known Cu stress-responsive genes during tomato fruit ripening depending on Cu availability, which allowed potential candidates to be targeted for biotechnological improvements in reproductive tissues. We provide the first study characterizing the molecular responses of fruit to Cu deficiency stress for any fruit crop.

Effect of Rootstock on ‘Tasti-Lee’ Tomato Yield and Fruit Quality in a High Tunnel Production System

Grafting tomatoes with vigorous rootstocks can be used to increase yield in high tunnels without significant soilborne disease pressure. However, evidence suggests that grafting with high-yielding rootstocks could compromise the accumulation of primary and secondary metabolites. ‘Tasti Lee’ is a hybrid tomato that is bred to have a superior fresh-eating quality and higher lycopene content. The objective of this experiment was to investigate the yield and fruit quality impacts of grafting ‘Tasti Lee’ with rootstocks with ranging vigor and typical yield performance in high tunnels. Nongrafted ‘Tasti-Lee’ and ‘Tasti-Lee’ scion grafted onto ‘Maxifort’, ‘DRO141TX’, ‘Fortamino’, ‘Estamino’, and ‘RST-04-106-T’ rootstocks were trialed in a high tunnel in Kansas for three consecutive growing seasons (2018–20). The trials were arranged in a randomized complete block design with four replications. Total yield, marketable yield, average fruit size, and distribution of fruit size classes were assessed. Red ripe tomato fruit were harvested to determine the soluble solids content, titratable acidity, lycopene content, vitamin C content, antioxidant capacity, and fruit firmness. ‘Maxifort’, ‘DRO141TX’, ‘Estamino’, and ‘Fortamino’ significantly increased marketable yield (kg/plant) by 31.5% to 47.0% more than nongrafted plants. In contrast, ‘RST-04-106-T’ did not lend any significant yield benefit. Regardless of the rootstock, grafting increased the marketable average fruit weight by 20 g. Grafting did not have significant effects on any of the fruit quality attributes assessed. However, the soluble solids content of fruit from plants grafted to ‘RST-04-106-T’ was 10% higher (P < 0.05) than that grafted to ‘Maxifort’, indicating that rootstock genotype can influence this quality trait. Our findings suggest that growers can graft the tomato ‘Tasti-Lee’ with select vigorous rootstocks to increase marketable yield without sacrificing fruit quality for high tunnel production.

Increased ACS Enzyme Dosage Causes Initiation of Climacteric Ethylene Production in Tomato.

Fruits of wild tomato species show different ethylene-dependent ripening characteristics, such as variations in fruit color and whether they exhibit a climacteric or nonclimacteric ripening transition. 1-Aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) and ACC oxidase (ACO) are key enzymes in the ethylene biosynthetic pathway encoded by multigene families. Gene duplication is a primary driver of plant diversification and angiosperm evolution. Here, interspecific variations in the molecular regulation of ethylene biosynthesis and perception during fruit ripening in domesticated and wild tomatoes were investigated. Results showed that the activated ACS genes were increased in number in red-ripe tomato fruits than in green-ripe tomato fruits; therefore, elevated dosage of ACS enzyme promoted ripening ethylene production. Results showed that the expression of three ACS isogenes ACS1A, ACS2, and ACS4, which are involved in autocatalytic ethylene production, was higher in red-ripe tomato fruits than in green-ripe tomato fruits. Elevated ACS enzyme dosage promoted ethylene production, which corresponded to the climacteric response of red-ripe tomato fruits. The data suggest that autoinhibitory ethylene production is common to all tomato species, while autocatalytic ethylene production is specific to red-ripe species. The essential regulators Non-ripening (NOR) and Ripening-Inhibitor (RIN) have experienced gene activation and overlapped with increasing ACS enzyme dosage. These complex levels of transcript regulation link higher ethylene production with spatiotemporal modulation of gene expression in red-ripe tomato species. Taken together, this study shows that bursts in ethylene production that accompany fruit color changes in red-ripe tomatoes are likely to be an evolutionary adaptation for seed dispersal.

Characterization of Glucuronosyl-diacyl/monoacylglycerols and Discovery of Their Acylated Derivatives in Tomato Lipid Extracts by Reversed-Phase Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry.

Glucuronic acid containing diacylglycerols (3-(O-α-d-glucuronopyranosyl)-1,2-diacyl-sn-glycerols, GlcA-DAG) are glycolipids of plant membranes especially formed under phosphate-depletion conditions. An analytical approach for the structural characterization of GlcA-DAG in red ripe tomato (Solanum lycopersicum L.) extracts, based on reversed-phase liquid chromatography (RPLC) coupled with electrospray ionization (ESI) and tandem mass spectrometry (MS/MS) using a linear ion trap, is described in this paper. At least 14 GlcA-DAG (R1/R2) species, including four regioisomers, containing three predominant fatty acyl chains C16:0, C18:2, and C18:3, were identified for the first time. Moreover, 29 GlcA-DAG acylated on the glucuronosyl ring (acyl-R3 GlcA-DAG) were discovered, alongside 15 acylated lyso-forms, i.e., acylated 3-(O-α-d-glucuronosyl)monoacylglycerols, abbreviated as acyl-R3 GlcA-MAG (R1/0) or (0/R2). Although many of these acylated lyso-forms were isomeric with GlcA-DAG (i.e., acyl chains with equivalent sum composition), they were successfully separated by reversed-phase liquid chromatography (RPLC) using a solid-core C18 column packed with 2.6 μm particle size. Tandem MS (and eventually MS3) data obtained from sodium adducts ([M + Na]+) and deprotonated molecules ([M - H]-) were fundamental to detect diagnostic product ions related to the glucuronosyl ring and then determine the identity of all investigated glycolipids, especially to recognize the acyl chain linked to the ring. A classification of GlcA-MAG, GlcA-DAG, and acylated GlcA-DAG and GlcA-MAG was generated by an in house-built database. The discovery of acylated derivatives emphasized the already surprising heterogeneity of glucuronic acid-containing mono- and diacylglycerols in tomato plants, stimulating interesting questions on the role played by these glycolipids.

Multiomics analyses reveal the roles of the ASR1 transcription factor in tomato fruits.

The transcription factor ASR1 (ABA, STRESS, RIPENING 1) plays multiple roles in plant responses to abiotic stresses as well as being involved in the regulation of central metabolism in several plant species. However, despite the high expression of ASR1 in tomato fruits, large scale analyses to uncover its function in fruits are still lacking. In order to study its function in the context of fruit ripening, we performed a multiomics analysis of ASR1-antisense transgenic tomato fruits at the transcriptome and metabolome levels. Our results indicate that ASR1 is involved in several pathways implicated in the fruit ripening process, including cell wall, amino acid, and carotenoid metabolism, as well as abiotic stress pathways. Moreover, we found that ASR1-antisense fruits are more susceptible to the infection by the necrotrophic fungus Botrytis cinerea. Given that ASR1 could be regulated by fruit ripening regulators such as FRUITFULL1/FRUITFULL2 (FUL1/FUL2), NON-RIPENING (NOR), and COLORLESS NON-RIPENING (CNR), we positioned it in the regulatory cascade of red ripe tomato fruits. These data extend the known range of functions of ASR1 as an important auxiliary regulator of tomato fruit ripening.

Postharvest Reduction of Salmonella enterica on Tomatoes Using a Pelargonic Acid Emulsion.

A novel produce wash consisting of pelargonic acid (PEL) emulsions was tested on tomatoes contaminated with a five-serovar Salmonella enterica cocktail. Ability to reduce contamination on the inoculated tomato surface, as well as mitigation of subsequent cross-contamination to uninoculated tomatoes washed in re-used/spent wash water were examined. Sanitizer efficacy was also examined over 1 and 7 d storage time (8 °C, recommended for red ripe tomatoes) and in the presence of 0.5% (w/v) organic load. PEL performed statistically the same (p ≤ 0.05) at both 30 mM and 50 mM concentrations and resulted in greater than 1, 5 and 6 log CFU/g Salmonella reductions at 0 h, 1 d and 7 d, respectively, when compared to a water-only or no rinse (NR) treatment. This was also a significantly greater reduction than was observed due to chlorine (sodium hypochlorite) and peroxyacetic acid (PAA) at all time points (p ≤ 0.01). Organic load had no impact on sanitizer efficacy for all examined treatments. Finally, PEL had a deleterious impact on tomato texture. At 1 d, ca. 5 N and 7 N were required to achieve tomato skin penetration and compression, respectively, compared to >9 N and 15 N required by all other treatments (p ≤ 0.05). While PEL sanitizers effectively reduced inoculated Salmonella and subsequent transfer to uninoculated tomatoes, reformulation may be necessary to prevent deleterious quality impacts on produce.

Challenges and Prospects of New Plant Breeding Techniques for GABA Improvement in Crops: Tomato as an Example.

Over the last seven decades, γ-aminobutyric acid (GABA) has attracted great attention from scientists for its ubiquity in plants, animals and microorganisms and for its physiological implications as a signaling molecule involved in multiple pathways and processes. Recently, the food and pharmaceutical industries have also shown significantly increased interest in GABA, because of its great potential benefits for human health and the consumer demand for health-promoting functional compounds, resulting in the release of a plethora of GABA-enriched products. Nevertheless, many crop species accumulate appreciable GABA levels in their edible parts and could help to meet the daily recommended intake of GABA for promoting positive health effects. Therefore, plant breeders are devoting much effort into breeding elite varieties with improved GABA contents. In this regard, tomato (Solanum lycopersicum), the most produced and consumed vegetable worldwide and a fruit-bearing model crop, has received much consideration for its accumulation of remarkable GABA levels. Although many different strategies have been implemented, from classical crossbreeding to induced mutagenesis, new plant breeding techniques (NPBTs) have achieved the best GABA accumulation results in red ripe tomato fruits along with shedding light on GABA metabolism and gene functions. In this review, we summarize, analyze and compare all the studies that have substantially contributed to tomato GABA breeding with further discussion and proposals regarding the most recent NPBTs that could bring this process to the next level of precision and efficiency. This document also provides guidelines with which researchers of other crops might take advantage of the progress achieved in tomato for more efficient GABA breeding programs.

Functional analysis of tomato rhamnogalacturonan lyase gene Solyc11g011300 during fruit development and ripening

Rhamnogalacturonan I (RG-I) is a domain of plant cell wall pectin. The rhamnogalacturonan lyase (RGL) enzyme (EC 4.2.2.23) degrades RG-I by cleaving the α-1,4 glycosidic bonds located between the l-rhamnose and d-galacturonic residues of the main chain. While RGL’s biochemical mode of action is well known, its effects on plant physiology remain unclear. To investigate the role of the RGL enzyme in plants, we have expressed the Solyc11g011300 gene under a constitutive promoter (CaMV35S) in tomato cv. ‘Ohio 8245’ and evaluated the expression of this and other RGL genes, enzymatic activity and alterations in vegetative tissue, and tomato physiology in transformed lines compared to the positive control (plants harboring the pCAMBIA2301 vector) and the isogenic line. The highest expression levels of the Solyc11g011300, Solyc04g076630, and Solyc04g076660 genes were observed in leaves and roots and at 10 and 20 days after anthesis (DAA). Transgenic lines exhibited lower RGL activity in leaves and roots and during fruit ripening, whereas higher activity was observed at 10, 20, and 30 DAA than in the isogenic line and positive control.Both transgenic lines showed a lower number of seeds and fruits, higher root length, and less pollen germination percentage and viability. In red ripe tomatoes, transgenic fruits showed greater firmness, longer shelf life, and reduced shriveling than did the isogenic line. Additionally, a delay of one week in fruit ripening in transgenic fruits was also recorded. Altogether, our data demonstrate that the Solyc11g011300 gene participates in pollen tube germination, fruit firmness, and the fruit senescence phenomena that impact postharvest shelf life.

Impact of early harvesting and two cold storage technologies on eating quality of red ripe tomatoes

Tomato fruits of cv. Caramba harvested at the pink ripening stage were cold stored for 4 and 7 days at 6 °C, then allowed to fully ripen at ambient temperature, and finally evaluated for eating quality, and compared with fruit fully ripened on the vine. In addition, fruits harvested at full ripeness were subjected to cold storage at 6 °C by a conventional or the innovative passive refrigeration PRS™ system for 2, 4, and 7 days, and then evaluated. Tomato quality evaluation included sensory, chemical (volatile compounds, sugars, and organic acids), and physical (flesh texture and skin colour) attributes. Fruit harvested at the pink stage, and then subjected to cold storage, when attained full external red colour showed less intense tomato odour, red ripe tomato odour, and flavour when compared to fruit fully ripened on the vine, and, at the same time, developed a perceptible mould off-odour. These differences were consistent with those observed in the levels of aroma compounds and fermentation metabolites. Main effects associated with cold storage of red ripe fruits by both conventional and passive refrigeration were increased skin toughness and decreased sourness. Passive refrigeration caused a more pronounced toughening of the skin, but no development off-odours were detected. Analysis of alteration of volatile synthesis confirmed recent findings on the molecular mechanism underlying chilling-induced loss of flavour in tomatoes.

The cis-lycopene isomers composition in supercritical CO2 extracted tomato by-products

The use of concentrated carotenoid extracts from red-ripe tomato by-products in traditional foods can improve the functional properties of the product while increasing the efficiency of industrial red-ripe tomatoes processing. In red tomatoes, lycopene is almost exclusively found in the all-trans-form, but during processing lycopene can undergo isomerisation to cis-lycopene isomers. The cis-lycopene isomers offer potentially better health benefits than the trans-lycopene isomers. The objectives of this study were to optimize supercritical carbon dioxide (SC-CO2) extraction parameters for the isolation of the non-polar tomato by-product fraction (oleoresin) and cis-lycopene isomers by using a central composite rotatable design (CCD) model with response surface methodology (RSM). SC-CO2 using CCD and RSM was used for the first time for the isolation of cis-lycopene isomers from tomato by-products. The best results in terms of oleoresin yield were obtained at a temperature of 73.9 °C, a pressure of 53.7 MPa and a time of 155 min, whereas the optimal extraction process parameters of cis-lycopene isomers are a 52 °C temperature, a 55 MPa pressure and a 180 min extraction time. The optimized conditions of SC-CO2 allows to obtain high yields of lycopene rich extracts (oleoresins) comprising higher percentage of cis-lycopene isomers (∼62% of total lycopene).

Bilayer edible coating with chitosan and wax extended shelf life and maintained quality of tomatoes at ambient storage

Tomato, a widely consumed fruit vegetable rich in neutraceuticals, faced significant loss during ambient storage and chilling injury in refrigerated storage, which resulted in poor shelf life. Thus, the present experiment was conducted with red ripe tomato cv. Samrudhi to study the influence of chitosan (2%), wax and carboxy methyl cellulose (CMC 3%), single or bilayer coating on shelf life and quality at ambient storage. Results showed that tomatoes coated with chitosan 2%+wax had minimum weight loss (4.57%) and fruit decay (9.58%), whereas TSS: acid ratio (13.66), ascorbic acid (15.28 mg/100 g), and lycopene (24.76 μg/g) contents were found reasonably high at 15 DAS compared to other treatments and caused average shelf life of 28.67 days. However, fruits coated with chitosan 2%+CMC 3% also had high shelf life (24.46 days) compared to control (15.25 days).

Fruit preferential activity of the tomato RIP1 gene promoter in transgenic tomato and Arabidopsis

Isolation and functional characterization of tissue- and stage-specific gene promoters is beneficial for genetic improvement of economically important crops. Here, we have characterized a putative promoter of a ripening-induced gene RIP1 (Ripening induced protein 1) in tomato. Quantification of the transcript level of RIP1 showed that its expression is fruit preferential, with maximum accumulation in red ripe fruits. To test the promoter activity, we made a reporter construct by cloning 1450bp putative RIP1 promoter driving the GUS (ß-glucuronidase) gene expression and generated stable transgenic lines in tomato and Arabidopsis. Histochemical and fluorometric assays validated the fruit-specific expression of RIP1 as the highest GUS activity was found in red ripe tomatoes. Similarly, we detected high levels of GUS activity in the siliques of Arabidopsis. On the contrary, weak GUS activity was found in the flower buds in both tomato and Arabidopsis. To characterize the specific regions of the RIP1 promoter that might be essential for its maximum activity and specificity in fruits, we made stable transgenic lines of tomato and Arabidopsis with 5'-deletion constructs. Characterization of these transgenic plants showed that the full length promoter is essential for its function. Overall, we report the identification and characterization of a ripening-induced promoter of tomato, which would be useful for the controlled manipulation of the ripening-related agronomic traits in genetic manipulation studies in future.

Identification of Loci Affecting Accumulation of Secondary Metabolites in Tomato Fruit of a Solanum lycopersicum × Solanum chmielewskii Introgression Line Population.

Semi-polar metabolites such as flavonoids, phenolic acids, and alkaloids are very important health-related compounds in tomato. As a first step to identify genes responsible for the synthesis of semi-polar metabolites, quantitative trait loci (QTLs) that influence the semi-polar metabolite content in red-ripe tomato fruit were identified, by characterizing fruits of a population of introgression lines (ILs) derived from a cross between the cultivated tomato Solanum lycopersicum and the wild species Solanum chmielewskii. By analyzing fruits of plants grown at two different locations, we were able to identify robust metabolite QTLs for changes in phenylpropanoid glycoconjugation on chromosome 9, for accumulation of flavonol glycosides on chromosome 5, and for alkaloids on chromosome 7. To further characterize the QTLs we used a combination of genome sequencing, transcriptomics and targeted metabolomics to identify candidate key genes underlying the observed metabolic variation.

Lycopene estimates in terms of chromaticity value in tomato (Solanum lycopersicum)

Lycopene content as well as colour are the most important factors in the visual and nutraceutical quality of tomatoes (Solanum lycopersicum L.) and these factors are affected by temperature and light in different condition. In the present study color development in terms of chromaticity value (L, a, b and a/b) and lycopene accumulation in tomato fruits cv. Naveen known for virus resistant with prolific bearing, was assessed independently at different maturity stages, viz. breaking, turning, pinkish, red and red ripe, grown in greenhouse and compared with the fruits grown in open condition. The data on light and temperature were recorded periodically throughout the experimental period. The lycopene content (0.779±0.008 mg/FW) and chromacity value (a/b 0.908) were maximum in red ripe tomato fruits harvested from greenhouse as compared to open condition (0.099±0.006 mg/FW and 0.612 , respectively) . The direct relationships between chromaticity value and lycopene concentration at different stages was obtained. Thus the assessment of chromaticity value can be used as a nondestructive method to envisage the lycopene content in tomato fruits.

FT-IR and FT-Raman characterization of non-cellulosic polysaccharides fractions isolated from plant cell wall

The purpose of this work was to reveal the structural changes of cell wall polysaccharides’ fractions during tomato fruit development by analysis of spectral data. Mature green and red ripe tomato fruit were taken into consideration. The FT-IR spectra of water soluble pectin (WSP), imidazole soluble pectin (ISP) and diluted alkali soluble pectin (DASP) contained bands typical for pectins. Whereas for KOH fraction spectra bands typical for hemicelluloses were present. The FT-IR spectra showed the drop down of esterification degree of WSP and ISP polysaccharides during maturation. The changes in polysaccharides structure revealed by spectra were the most visible in the case of pectic polysaccharides. The WSP and DASP fraction pectins molecules length were shortened during tomato maturation and ripening. Whereas the ISP fraction spectra analysis showed that this fraction contained rhamnogalacturonan I, but also for red ripe was rich in pectic galactan comparing with ISP fraction from mature green.

Chilling-Induced Changes in Aroma Volatile Profiles in Tomato.

Fruit and vegetables are regularly stored by consumers in the refrigerator at temperatures that may be well below the recommended storage temperatures. Apart from causing visible symptoms such as watery, sunken areas on the skin, chilling may also induce changes in fruit textural properties and flavour. The aim of this research was to investigate the effect of low temperature storage on tomato flavour and off-flavour production. To more closely mimic the real-consumer aroma perception while eating, in addition to the standard solid-phase microextraction gas chromatography–mass spectrometry (SPME/GC-MS) analysis, volatiles were also measured using a chewing device connected to a proton-transfer reaction–mass spectrometer (PTR-MS). Aroma volatiles were assessed in red ripe tomatoes of the cvs Cappricia RZ (round truss) and Amoroso RZ (cocktail truss) stored at refrigerator temperature (4 °C) and at higher temperatures (16 and 22 °C) for 20 days. The changes in aroma production were also monitored when the fruit was brought from room to refrigerator temperature and vice versa. After bringing the fruit from room to refrigerator temperature, the abundance of most volatiles was greatly reduced within 3 to 5 h, closely following the decrease in fruit temperature. When temperature was restored to room temperature following varying times of cold storage, the abundance of most volatiles increased again, but generally not to the original levels. Overall, the effects of low temperature storage on the decrease in volatile abundance were more pronounced in cv Cappricia RZ than in cv Amoroso RZ. On the contrary, the production of off flavours following prolonged cold storage was more pronounced in cv Amoroso RZ than in cv Cappricia RZ. Apart from changes in the overall abundance of the volatiles, marked changes in the volatile profile were observed in fruit stored for longer times in the cold and this may at least in part explain the negative effect of cold storage on overall tomato flavour.

Factors That Affect Proliferation of Salmonella in Tomatoes Post-Harvest: The Roles of Seasonal Effects, Irrigation Regime, Crop and Pathogen Genotype

Main ObjectivesFresh fruits and vegetables become increasingly recognized as vehicles of human salmonellosis. Physiological, ecological, and environmental factors are all thought to contribute to the ability of Salmonella to colonize fruits and vegetables pre- and post-harvest. The goal of this study was to test how irrigation levels, fruit water congestion, crop and pathogen genotypes affect the ability of Salmonella to multiply in tomatoes post-harvest.Experimental DesignFruits from three tomato varieties, grown over three production seasons in two Florida locations, were infected with seven strains of Salmonella and their ability to multiply post-harvest in field-grown tomatoes was tested. The field experiments were set up as a two-factor factorial split plot experiment, with the whole-plot treatments arranged in a randomized complete-block design. The irrigation treatment (at three levels) was the whole-plot factor, and the split-plot factor was tomato variety, with three levels. The significance of the main, two-way, and three-way interaction effects was tested using the (type III) F-tests for fixed effects. Mean separation for each significant fixed effect in the model was performed using Tukey’s multiple comparison testing procedure.Most Important Discoveries and SignificanceThe irrigation regime per se did not affect susceptibility of the crop to post-harvest proliferation of Salmonella. However, Salmonella grew significantly better in water-congested tissues of green tomatoes. Tomato maturity and genotype, Salmonella genotype, and inter-seasonal differences were the strongest factors affecting proliferation. Red ripe tomatoes were significantly and consistently more conducive to proliferation of Salmonella. Tomatoes harvested in the driest, sunniest season were the most conducive to post-harvest proliferation of the pathogen. Statistically significant interactions between production conditions affected post-harvest susceptibility of the crop to the pathogen. UV irradiation of tomatoes post-harvest promoted Salmonella growth.