Genetic identification and genomic organization of factors affecting fruit texture.
ABSTRACT Fleshy fruits are an essential part of the human diet providing vital vitamins, minerals and other health-promoting compounds. The texture of the ripe fruit has a significant effect on quality and influences consumer acceptance, shelf-life, resistance, and transportability. The development of rational approaches to improve texture and shelf-life depend on understanding the biological basis of fruit ripening. Until recently, work has focused on the isolation of ripening-related genes from a variety of fleshy fruits. However, little is known about the genes that regulate this complex developmental process or whether similar regulatory genes are active in all fruiting species. A major breakthrough would be the identification of generic genes associated with texture and other aspects of ripening in fleshy fruits. In tomato, a small number of single gene mutations exist, such as ripening-inhibitor (rin), non-ripening (nor), Never-ripe (Nr), and Colourless non-ripening (Cnr) which have pleiotropic effects resulting in the reduction or almost complete abolition of ripening. These mutations probably represent lesions in regulatory genes. The cloning of the wild-type alleles of RIN and NOR is reported by Moore et al. in this issue. This review focuses on the texture characteristics of the Cnr mutant. A possible framework for the molecular regulation of fruit texture is discussed and quantitative genetic approaches to determining the generic attributes of fruit texture are explored.
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ABSTRACT: Tomato (Solanum lycopersicum L.) is an important food commodity from nutritional and commercial point of view, however, freshly harvested tomato has shorter shelf life in the market. Tomato coated with gum Arabic (5-20% solution) was evaluated during 16 day storage at 24±1°C. Firmness of uncoated fruits was significantly (p ≤ 0.05) lower and weight loss higher. Uncoated fruits had higher total solids, lower acidity and uneven pH. L and b values decreased while a value increased. Hue angle of fruits decreased and total color change increased, significantly. Chroma and browning index increased slightly while the color index increased significantly. The kinetic models of color change were dependent on gum concentration. Coated fruits had good sensory acceptability till 8-12 days. Tomato strategies to preserve its physico-chemical and sensorial characteristics have significance for grower, processor and seller. We observed that gum Arabic coating effectively preserved different quality attributes of tomato fruits at even elevated storage temperature for longer time.Journal of Food Agriculture and Environment 05/2013; 11(2):142-148. · 0.44 Impact Factor
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ABSTRACT: A hyperspectral reflectance and transmittance imaging system was developed to non-destructively evaluate the comprehensive mechanical properties of blueberry. Reflectance and transmittance spectra were extracted from segmented hyperspectral images of whole fruit and correlated with fruit mechanical properties obtained from Texture Profile Analysis and Puncture Analysis using least squares-support vector machine. A random frog spectral selection approach was applied to collect informative wavelengths. Prediction models based on random frog selected reflectance and transmittance spectra gave similar results to those based on respective full spectra. Combined spectra with single random frog, which were obtained by combining random frog selected reflectance and transmittance into one spectral vector, were feasible for predicting hardness, springiness, resilience, force max and final force, with Rp (RPD) values of 0.86 (1.78), 0.72 (1.73), 0.79 (1.78), 0.77 (1.51) and 0.84 (1.72), respectively. When applying random frog again for combined spectra with single random frog, the obtained models were also satisfactory with fewer wavelengths. In conclusion, the use of hyperspectral reflectance and transmittance as well as their combined spectra, coupled with random frog approach, showed a considerable potential for predicting blueberry mechanical properties.Postharvest Biology and Technology 04/2015; 106:1-10. DOI:10.1016/j.postharvbio.2015.03.014 · 2.63 Impact Factor
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ABSTRACT: Background Apple fruit mealiness is one of the most important textural problems that results from an undesirable ripening process during storage. This phenotype is characterized by textural deterioration described as soft, grainy and dry fruit. Despite several studies, little is known about mealiness development and the associated molecular events. In this study, we integrated phenotypic, microscopic, transcriptomic and biochemical analyses to gain insights into the molecular basis of mealiness development.ResultsInstrumental texture characterization allowed the refinement of the definition of apple mealiness. In parallel, a new and simple quantitative test to assess this phenotype was developed.Six individuals with contrasting mealiness were selected among a progeny and used to perform a global transcriptome analysis during fruit development and cold storage. Potential candidate genes associated with the initiation of mealiness were identified. Amongst these, the expression profile of an early down-regulated transcript similar to an Arabidopsis thaliana pectin methylesterase gene (AtPME2) matched with mealiness development. In silico analyses of this Malus x domestica PME gene (MdPME2) confirmed its specific pattern compared with all other identified MdPME genes. Protein fusion experiments showed that MdPME2 is secreted into the apoplast in accordance with a possible activity on pectin structure. Further microscopic analysis indicated a progressive loss of cell to cell adhesion in mealy apple fruits. Biochemical analysis revealed specific modifications of pectin residues associated with mealiness, without global changes in the degree of methylesterification of pectins.Conclusions These data support the role of PME in cell wall remodelling during apple fruit development and ripening and suggest a local action of these enzymes. Mealiness may partially result from qualitative and spatial variations of pectin microarchitecture rather than quantitative pectin differences, and these changes may occur early in fruit development. The specific MdPME2 gene highlighted in this study could be a good early marker of texture unfavourable trait in apple.BMC Plant Biology 12/2014; 14(1):1593. DOI:10.1186/s12870-014-0375-3 · 3.94 Impact Factor