Lettuce quality loss under conditions that favor the wilting phenomenon

Agüero, María Victoria; Ponce, Alejandra Graciela; Moreira, M.R.; Roura, Sara I.

doi:10.1016/j.postharvbio.2010.08.018

Cited by 66 publications

(51 citation statements)

References 15 publications

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“…After image acquisition, the water content and osmotic potential were determined for the harvested leaves. The leaf water contents were estimated following the method described by [23] with modifications. Twenty grams of leaf pieces per treatment were taken, homogenized with a commercial grinder, and divided into three samples of five grams per treatment.…”

Section: Materials and Analytical Measurementsmentioning

confidence: 99%

Hyperspectral Imaging to Evaluate the Effect of IrrigationWater Salinity in Lettuce

et al. 2016

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Salinity is one of the most important stress factors in crop production, particularly in arid regions. This research focuses on the effect of salinity on the growth of lettuce plants; three solutions with different levels of salinity were considered and compared (S1 = 50, S2 = 100 and S3 = 150 mM NaCl) with a control solution (Ct = 0 mM NaCl). The osmotic potential and water content of the leaves were measured, and hyperspectral images of the surfaces of 40 leaves (10 leaves per treatment) were taken after two weeks of growth. The mean spectra of the leaves (n = 32,000) were pre-processed by means of a Savitzky-Golay algorithm and standard normal variate normalization. Principal component analysis was then performed on a calibration set of 28 mean spectra, yielding an initial model for salinity effect detection. A second model was subsequently proposed based on an index computing an approximation to the second derivative at the red edge region. Both models were applied to all the hyperspectral images to obtain the corresponding artificial images, distinguishing between the 28 that were used to extract the calibration mean spectra and the rest that constituted an external validation. Those virtual images were studied using analysis of variance in order to compare their ability for detecting salinity effects on the leaves. Both models showed significant differences between each salinity level, and the hyperspectral images allowed observations of the distribution of the salinity effects on the leaf surfaces, which were more intense in the areas distant from the veins. However, the index-based model is simpler and easier to apply because it is based solely on the reflectance at three different wavelengths, thus allowing for the implementation of less expensive multispectral devices.

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Section: Materials and Analytical Measurementsmentioning

confidence: 99%

Hyperspectral Imaging to Evaluate the Effect of IrrigationWater Salinity in Lettuce

et al. 2016

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“…This shows the importance of silicon in maintaining fresh matter and the post-harvest quality of the leaves, thus representing a possibility for producers and traders to achieve more and more distant markets. In studies with lettuce 'Lores' submitted to two conditions of optimum relative humidity (95-98%) and low (70-72%), during the storage temperature at 0 to 2°C resulted in fresh matter losses of up to 18% after 5 days of storage for plants subjected to the condition of low relative humidity, while for treatment under optimal conditions of relative humidity that loss was up to 5%, indicating the importance of the relative humidity controlling for the quality of vegetable products (Agüero et al, 2011). The shriveling and wrinkling of the greenery occur due to perspiration which is caused due to the vapor pressure difference that exists between the plant and the environment (Paliyath et al, 2008).…”

Section: Resultsmentioning

confidence: 99%

“…The sales volume of this leafy vegetable in CEAGESP in 2012 was 30,188 tons (Agrianual, 2013). The maintenance of the appearance and the fresh consistency of lettuce is a challenge, since, after harvesting, the exposure to environmental conditions favor the water loss by the product damaging the quality and reducing the shelf life of the greenery (Agüero et al, 2011). Therefore it is important to adopt post-harvest and cultural practices aiming to prolong the commercial quality of the products.…”

Section: Introductionmentioning

confidence: 99%

Silicon in the turgidity maintenance of American lettuce

Mattiuz¹,

Filho²,

Muniz³

et al. 2015

Afr. J. Agric. Res.

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This study aimed to verify the influence of silicon application in hydroponics lettuce cv Lucy Brown, on post-harvest under refrigeration. In hydroponic production silicon was used in the doses of 0, 28, 56 and 84 mg L -1 of potassium silicate. Lettuces were harvested early in the morning and immediately transported to UNESP, campus of Jaboticabal. Upon being received at the laboratory the plants were standardized in size and appearance, removing the three older leaves. The plants were placed in polystyrene trays (Styrofoam © ) and packaged under the temperature at 8±2°C and 80 ± 3% relative humidity. The experimental design was completely randomized with three replications, and two plants per repetition. The fresh matter of shoots was analyzed together with the silicon content in the leaves, the firmness, the fresh matter loss, titratable acidity, pH and enzyme activity of polyphenoloxidize and peroxides. The evaluations were performed every four days, for a total of 16 days of storage. The concentration of 84 mg L -1 silicon increased the fresh matter of the plant at harvest and post-harvest, provided less water loss and consequently greater firmness in the leaves during the storage period for lettuce at 8±2°C for 16 days.

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“…This weight loss corresponds to the natural catabolism process in vegetable commodities, catalysed by enzymes and accelerated by the minimal processing [19].…”

Section: Weight Lossmentioning

confidence: 99%

Effect of Lactoperoxidase System on Microbiological and Quality Markers of Minimally Processed Lettuce

Telmoudi¹,

Hassouna²

2017

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Minimally processed lettuce is sensitive to microbial attack caused by the loss of natural resistance and their high water content and nutrients. The use of natural anti-microbial agents such as the lactoperoxidase system (LPS) represents an interesting alternative to the use of chemical treatments. This study focused on the importance of LPS and its efficiency as a bioprotective agent. The effect of washing with LPS, at two different concentrations (4 and 5 IU) and four different treatment times (1, 2, 3 and 4 h) on microbial growth in fresh-cut lettuce, was determined at 30˚C and compared with a 80 ppm chlorine at 4˚C for 20 min. The results deduced that both doses of LPS showed significant reductions in microbial growth when applied during 4 h, but the highest dose proved to be more effective. No significant differences were found between the LPS treatment and chlorine considering native microflora reduction and quality markers during storage.

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Lettuce quality loss under conditions that favor the wilting phenomenon

Cited by 66 publications

References 15 publications

Hyperspectral Imaging to Evaluate the Effect of IrrigationWater Salinity in Lettuce

Hyperspectral Imaging to Evaluate the Effect of IrrigationWater Salinity in Lettuce

Silicon in the turgidity maintenance of American lettuce

Effect of Lactoperoxidase System on Microbiological and Quality Markers of Minimally Processed Lettuce

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