Use of Sub-Atmospheric Pressure Storage to Improve the Quality and Shelf-Life of Marmande Tomatoes cv. Rojito

In this study, the feasibility of storing Marmande tomatoes (Solanum lycopersicum, cv Rojito) under hypobaric conditions was evaluated. The fruits were sorted into four lots of 72 fruits each. One lot was considered as a control, and the fruits were kept in the open box, while the fruits of the rest of the three remaining lots were enclosed in airtight containers and subjected to 101, 75 and 50 Kpa, respectively. Control fruits and airtight containers were kept at room temperature, and every three days from the beginning of the experiment the following main quality parameters were analysed: ethylene production rate, firmness, colour, total solids content, ascorbic acid, total phenolics and pigments, as well as a sensory analysis carried out by panellists. The results show that sub-atmospheric storage led a reduction in ethylene production, which was associated with a delay in ripening. The differences in the evolution of pigments were very significant, while a large degradation of chlorophylls was observed in the control fruits and in those kept at 101 kPa, in the fruits kept at 75 kPa and 50 kPa the degradation was much slower. In relation to carotenoid pigments, it was observed that sub-atmospheric treatments delayed their appearance compared to control and 101 kPa fruits. In relation to other quality parameters, it was found that control fruit and fruit held at 101 kPa softened more rapidly than fruit under sub-atmospheric conditions, whose loss of firmness was more gradual with differences found only at 9 and 12 days of storage with respect to fruit firmness at harvest. The appearance of these fruits was evaluated with the same score as at the time of harvesting, during 9 of the 12 days of the experiment, then a positive effect of sub-atmospheric treatments was also found in the sensory analysis. The results suggest that sub-atmospheric storage could be a suitable method of increasing the shelf-life of fruits

Effect of Ethylene-Insensitive Mutation etr2b on Postharvest Chilling Injury in Zucchini Fruit

Zucchini is a vegetable fruit that is very susceptible to postharvest chilling injury, and fruit ethylene production is correlated with chilling injury sensitivity, such that the more tolerant the cultivar, the lower is its ethylene production. It is expected that zucchini fruit with reduced sensitivity to ethylene would have a higher chilling injury tolerance. In this study, we compared the postharvest fruit quality of wild type and ethylene-insensitive mutant etr2b, in which a mutation was identified in the coding region of the ethylene receptor gene CpETR2B. Flowers from homozygous WT (wt/wt), mutant plants in homozygous (etr2b/etr2b) and heterozygous (wt/etr2b) were hand-pollinated, and all fruits were harvested with the same length, at about 8 days after pollination. After harvesting, fruit of each genotype was randomly divided in 3 batches of 12 fruits each (four replications with three fruits each), and then stored at 4 °C and 95% RH. At 0, 7, and 14 days after cold storage, each batch was used to assess ethylene production, respiration rate, weight and firmness loss, chilling injury, and oxidative stress metabolites. The results showed a lower chilling injury associated with lower cold-induced ethylene production in the mutant fruit, in comparison with the WT fruit. These data demonstrated that the ethylene-insensitive etr2b mutant fruit was more tolerant to chilling injury, confirming that basal ethylene in the still undamaged fruit could function as a modulator of post-harvest chilling injury. Moreover, the higher chilling tolerance of the etr2b mutant fruit was not associated with MDA content, but was concomitant with a reduction in the accumulation of hydrogen peroxide in the refrigerated mutant fruit

Individual Shrink Wrapping of Zucchini Fruit Improves Postharvest Chilling Tolerance Associated with a Reduction in Ethylene Production and Oxidative Stress Metabolites

We have studied the effect of individual shrink wrapping (ISW) on the postharvest performance of refrigerated fruit from two zucchini cultivars that differ in their sensitivity to cold storage: Sinatra (more sensitive) and Natura (more tolerant). The fruit was individually shrink wrapped before storing at 4°C for 0, 7 and 14 days. Quality parameters, ethylene and CO2 productions, ethylene gene expression, and oxidative stress metabolites were assessed in shrink wrapped and non-wrapped fruit after conditioning the fruit for 6 hours at 20°C. ISW decreased significantly the postharvest deterioration of chilled zucchini in both cultivars. Weight loss was reduced to less than 1%, pitting symptoms were completely absent in ISW fruit at 7 days, and were less than 25% those of control fruits at 14 days of cold storage, and firmness loss was significantly reduced in the cultivar Sinatra. These enhancements in quality of ISW fruit were associated with a significant reduction in cold-induced ethylene production, in the respiration rate, and in the level of oxidative stress metabolites such as hydrogen peroxide and malonyldialdehyde (MDA). A detailed expression analysis of ethylene biosynthesis, perception and signaling genes demonstrated a downregulation of CpACS1 and CpACO1 genes in response to ISW, two genes that are upregulated by cold storage. However, the expression patterns of six other ethylene biosynthesis genes (CpACS2 to CpACS7) and five ethylene signal transduction pathway genes (CpCTR1, CpETR1, CpERS1, CpEIN3.1 and CpEN3.2), suggest that they do not play a major role in response to cold storage and ISW packaging. In conclusion, ISW zucchini packaging resulted in improved tolerance to chilling concomitantly with a reduction in oxidative stress, respiration rate and ethylene production, as well as in the expression of ethylene biosynthesis genes, but not of those involved in ethylene perception and sensitivity.This work was supported by grants AGL2011-30568-C02/ALI from the Spanish Ministry of Science and Innovation, and AGR1423 from the Consejería de Economía, Innovación y Ciencia, Junta de Andalucía, Spain. Z.M. acknowledges FPU program scholarships from MEC, Spain. S.M. is funded by grant PTA2011-479-I from the Spanish Ministry of Science and Innovation

Efecto de distintos tratamientos sobre los principios nutritivos, características fermentativas y digestibilidad in vitro de ensilados de subproducto de pimiento

Se ha analizado el efecto de diversos aditivos sobre la evolución de distintos parámetros bromatológicos y fermentativos en subproductos vegetales de invernadero (SVI) de pimiento tras 24 días de ensilado. Los aditivos y las proporciones en que se emplearon fueron las siguientes: i) ácido fórmico ii) un producto comercial: Ficpotenciado, a base de ácido propiónico y de sus sales, y iii) mezcla de SVI de pimiento con SVI de tomate. Se determinó la composición química (proteína bruta, proteína verdadera, nitrógeno no proteico, extracto etéreo, fibra neutro detergente, fibra ácido detergente, lignina ácido detergente, cenizas y materia seca), las características fermentativas (ácido láctico, ácido acético, nitrógeno soluble, nitrógeno amoniacal, pH) así como la producción de gas in vitro del material vegetal original y de los microensilados obtenidos. En general, las digestibilidades in vitro de los ensilados obtenidos son inferiores al material vegetal en fresco, debido fundamentalmente al aumento de la fracción fibrosa (excepto las obtenidas con la utilización del ácido fórmico), pero a su vez son similares a las de otros forrajes europeos tradicionales. Las mejores calidades de los ensilados obtenidos se muestran en los tratamientos realizados con ácido fórmico

Efecto de distintos tratamientos sobre los principios nutritivos, características fermentativas y digestibilidad in vitro de ensilados de subproducto de pimiento

Se ha analizado el efecto de diversos aditivos sobre la evolución de distintos parámetros bromatológicos y fermentativos en subproductos vegetales de invernadero (SVI) de pimiento tras 24 días de ensilado. Los aditivos y las proporciones en que se emplearon fueron las siguientes: i) ácido fórmico ii) un producto comercial: Ficpotenciado, a base de ácido propiónico y de sus sales, y iii) mezcla de SVI de pimiento con SVI de tomate. Se determinó la composición química (proteína bruta, proteína verdadera, nitrógeno no proteico, extracto etéreo, fibra neutro detergente, fibra ácido detergente, lignina ácido detergente, cenizas y materia seca), las características fermentativas (ácido láctico, ácido acético, nitrógeno soluble, nitrógeno amoniacal, pH) así como la producción de gas in vitro del material vegetal original y de los microensilados obtenidos. En general, las digestibilidades in vitro de los ensilados obtenidos son inferiores al material vegetal en fresco, debido fundamentalmente al aumento de la fracción fibrosa (excepto las obtenidas con la utilización del ácido fórmico), pero a su vez son similares a las de otros forrajes europeos tradicionales. Las mejores calidades de los ensilados obtenidos se muestran en los tratamientos realizados con ácido fórmico

Ethylene biosynthesis and signaling elements involved in chilling injury and other postharvest quality traits in the non-climacteric fruit of zucchini (Cucurbita pepo)

The immature non-climacteric fruit of zucchini is very sensitive to postharvest chilling injury (PCI). Although the fruit produces very low ethylene at harvest, cold storage induces an increase in ethylene production in the refrigerated fruit, and upon rewarming up to room temperature. The production of ethylene after rewarming was proportional to cold damage and found to be higher in the fruit of the cultivars most susceptible to chilling. The effects of the ethylene inhibitor 1-methycyclopropene (1-MCP) has been analyzed using the postharvest quality parameters of nine zucchini cultivars stored at 20 °C and 4 °C for 14 days. We have also determined the evolution of ethylene production in the fruit of these cultivars, and assessed the expression profiles of twelve ethylene biosynthesis and signaling genes in both control fruit and in 1-MCP treated fruit, of two cultivars that responded to 1-MCP. The 1-MCP treatment reduced the rate and delayed the onset of PCI symptoms and reduced fruit weight loss, although only in the fruit of the most chilling-susceptible cultivars, and concomitantly we found a reduction in the respiration rate and in the level of cold-induced ethylene. This data suggests that ethylene is not only a response of the fruit to cold damage, as occurs upon rewarming, but could also play a regulation role in the onset of PCI in this non-climacteric fruit. The genes CpACO1 and CpACS1 were found to be involved in the biosynthesis of the cold-induced ethylene, but the role played by CpACO1 was found to be the key function, since it was induced higher than CpACS1 in response to cold storage. More over CpACO1 was the only ethylene biosynthesis gene that was downregulated by the 1-MCP treatment. Some of the ethylene perception and signaling genes, including CpETR1, CpCTR1 and CpEIN3.1 were also induced in response to cold storage, and were downregulated in response to 1-MCP, indicating that the positive effect of 1-MCP in the fruit of certain zucchini cultivars is also associated with a downregulation of genes involved in ethylene perception and signal transduction pathways

Postharvest cold tolerance in summer squash and its association with reduced cold-induced ethylene production

Tolerance to postharvest chilling injury (PCI) is becoming an ever more essential trait for export-oriented vegetables requiring refrigerated transport and/or storage. Summer squash, Cucurbita pepo, is highly subjectto PCI.We screened a collection consisting of 80 long-fruited accessions of morphotypes zucchini, cocozelle, and vegetable marrow for cold tolerance. Of these, we selected the most cold tolerant and some of the least cold tolerant for further scrutiny. Fruits from each accession were stored for 7 and 14 days at 4 C before evaluating PCI, weight loss (WL) and ethylene production. Several accessions, including CpCAL003, CpCAL053 and CpCAL051, showed tolerance to PCI, with a lower percentage of the fruit surface suffering injury and WL at 4 C. The mode of inheritance of tolerance to PCI index and WL was investigated by crossing the tolerant accession designated CpCAL003 with the susceptible CpCAL112, and observing their filial- and backcross-generation progenies. The results indicate that cold tolerance is not conferred by a single gene, but rather is quantitatively inherited trait. Cold induced ethylene production co-segregated with PCI susceptibility. Thus, ethylene production under cold storage can be used as physiological indicator in selecting for PCI tolerance in summer squash

Postharvest quality in control and ISW fruit of Sinatra and Natura zucchini cultivars.

<p>(A) fruit pictures (B) weight loss, (C) chilling injury index, (D) firmness. Fruits of the two cultivars were harvested at a similar stage of development, shrink wrapped, stored for 0, 7 and 14 days at 4°C, and then rewarmed at 20°C for 6 hours before unwrapping and taking pictures and performing measurements. Control fruit was left unwrapped for the whole period of time. The results represent the mean and standard deviation of four independent replicates for each sample. Different letters indicate significant differences between samples for each storage time (<i>p</i>-value <0.05).</p

Expression profiles of ethylene biosynthesis genes in control and ISW fruit of Sinatra and Natura.

<p>Control and wrapped fruits of the two cultivars were stored for 0, 7 and 14 days at 4°C and then rewarmed at 20°C for 6 hours before collecting the exocarp material that was used for gene expression analyses. Transcript levels for each gene were assessed by quantitative RT-PCR. Data were standardized with the expression at harvest. Results represent the mean and standard deviation of three independent replicate samples for each cultivar, treatment and storage time.</p

Expression profiles of ethylene perception and signaling genes in control and ISW fruit of Sinatra and Natura.

<p>Control and wrapped fruits of the two cultivars were stored for 0, 7 and 14 days at different temperatures and then rewarmed at 20°C for 6 hours before colleting the exocarp material used for gene expression analyses. Transcript levels for each gene were assessed by quantitative RT-PCR. Data were standardized with the expression at harvest. Results represent the mean and standard deviation of three independent replicate samples for each cultivar, treatment and storage time.</p