Article

Effect of a photoselective filter on the yield and postharvest quality of 'Viroflay' baby spinach (Spinacia oleracea L.) leaves cultivated in a hydroponic system

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Abstract

Consumers are demanding foods with high sensory and nutritional quality including a higher content of compounds that help maintain good health. Given this scenario, new technologies are emerging to produce fresh salads that have the characteristics currently in demand. Shade nettings or photoselective filters on fruit and vegetable crops are a technology that provides protection, modifies the light spectrum resulting in a higher accumulation of antioxidant compounds, making them more desirable to consumers. The objective of this study was to compare the effect of shade netting on the fresh quality parameters of baby leaf spinach grown in a hydroponic system at harvest and after a period of 10 days at 4 • C. By using different shade netting colors, the average photosynthetic photon flux density (PPFD) that reaches the plants was modified during the growing period of baby leaf spinach (red: 118.35 μmol m − 2 s − 1 ; blue:117.96 μmol m − 2 s − 1 ; gray: 63.18 μmol m − 2 s − 1 and control without shade nettings: 278.12 μmol m − 2 s − 1). At harvest, baby leaf spinach grown under the red shade netting reached the highest yield. However, with the blue filter, leaves showed a value of 9.3 % dry weight, significantly higher than the values from red and gray filters with values of 7.3 and 6.3 %, respectively. The phenolic compound contents reached significantly higher values of 485.5 mg gallic acid equivalent (GAE) per 100 g − 1 FW for the baby leaf spinach grown under the red filter compared to the blue, gray and control filters with values of 472.5; 387.6 and 316.5 mg GAE per 100 g − 1 FW, respectively. The antioxidant capacity was significantly higher under the red filter. The sensory quality parameters indicated that spinach grown under color filters did not show off-flavors and maintained its turgidity and appearance at harvest. In the postharvest period, baby leaf spinach grown under red filter maintained the highest total phenol content and antioxidant activity after 10 days at 4 • C with similar appearance and turgidity as the control.

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... The measurements were taken in the axial part of the distal sector of the leaf using a tristimulus compact colorimeter (Minolta Chroma meter, CM -2500d, Japan). The results were expressed as hue, chroma (C) and lightness (L) (25). The longest three leaves were measured from another five random plants per repetition (to limit the length). ...
... The longest three leaves were measured from another five random plants per repetition (to limit the length). The measurements were made with a metric rule, where the maximum length and width were represented for the distance obtained from the base to the apex of the leaf above the midrib and the greatest distance perpendicular to the central rib of the leaf, respectively (25). The results were expressed in cm. ...
... The results were expressed in cm. The fresh weight (FW), dry weight (DW) and dry weight percentage (%DW) were measured with a precision balance (Radwag, AS 100/C/2, Poland) (25). For the DW, the samples were dried in a freeze dryer (ilShinBioBase, FD5508, Korea) until reaching a constant weight. ...
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... The measurements were taken in the axial part of the distal sector of the leaf using a tristimulus compact colorimeter (Minolta Chroma meter, CM -2500d, Japan). The results were expressed as hue, chroma (C) and lightness (L) (25). The longest three leaves were measured from another five random plants per repetition (to limit the length). ...
... The longest three leaves were measured from another five random plants per repetition (to limit the length). The measurements were made with a metric rule, where the maximum length and width were represented for the distance obtained from the base to the apex of the leaf above the midrib and the greatest distance perpendicular to the central rib of the leaf, respectively (25). The results were expressed in cm. ...
... The results were expressed in cm. The fresh weight (FW), dry weight (DW) and dry weight percentage (%DW) were measured with a precision balance (Radwag, AS 100/C/2, Poland) (25). For the DW, the samples were dried in a freeze dryer (ilShinBioBase, FD5508, Korea) until reaching a constant weight. ...
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The present study employed white (W), blue (B: 468 nm), red (R: 629 nm) and green (G: 524 nm) monochromatic LED lights for 26 days, from 11:00 to 18:00 h (7 h per day), with an average photosynthetic photon flux density (PPFD) of 26.0 m-2 s-1 on baby spinach leaves (Spinacia oleracea L.), cvs. Falcon F1 and Viroflay, grown in a hydroponic system. Regardless of the cultivar, the fresh and dry weights were positively influenced when the plants were irradiated by R-light in comparison to W-light. Independent of the cultivar, the leaves treated with Blight reached a significantly higher phenolic compound concentration and antioxidant capacity than plants irradiated with W-light. In addition, the green light increased total phenolic compound concentration. According to the results, the use of LED lights is a promising technique for the production of antioxidant compound-enriched leafy vegetables. Keywords LED light • biomass • spectrum • antioxidant capacity • hydroponic system • spinach Effect of LED light on the quality of spinach 99 Revista de la Facultad de Ciencias Agrarias-UNCuyo | Tomo 53-1-Año 2021 Resumen El presente estudio empleó luces LED monocromáticas blanca, azul (468 nm), roja (629 nm) y verde (524 nm) durante 26 días, desde las 11:00 hasta las 18:00 h (7 horas por día), con una densidad media de flujo fotosintético de 26,00 µmol m-2 s-1 sobre dos cultivares de espinaca (Spinacia oleracea L.) de hoja baby (Falcon F1 y Viroflay) cultivadas en un sistema hidropónico. Respecto del cultivar, los pesos fresco y seco fueron influenciados positivamente cuando las plantas fueron irradiadas con luz roja en comparación con las irradiadas con luz blanca. Independientemente del cultivar, las hojas tratadas con luz azul alcanzaron una concentración de compuestos fenólicos y capacidad antioxidante superiores a la de las plantas irradiadas con luz blanca. Además, la luz verde incrementó la concentración de compuestos fenólicos. De acuerdo con los resultados, el uso de luces LED es una técnica prometedora para la producción de hortalizas de hoja enriquecidas en compuestos antioxidantes. Palabras clave luces LED • biomasa • espectros • capacidad antioxidante • sistema hidropónico • espinaca
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... The higher altitude and rainfall, through their subsequent influence on the fruit growth and maturation stage, appear to be strongly related to the higher incidence of herbaceous off-flavor in sweet cherry. Additionally, the effect of light and solar radiation spectrum may influence the off-flavor profiles in plant foods, such as in baby spinach, though research in this area is still at its infancy (Lara et al. 2021). Riesling wines produced through shading, less vigor and in warmer climates generally have lower free "petrol-like" 1,1,6-trimethyl-1,2-dihydronaphthalene (Ziegler et al. 2020). ...
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... In a different way, Lara et al. [77] studied the light incidence by using different shade-netting colours (red: 118.35 µmol m −2 s −1 , blue: 117.96 µmol m −2 s −1 , grey: 63.18 µmol m −2 s −1 , and control without shade nettings: 278.12 µmol m −2 s −1 ). As other authors corroborated by using LED lighting, the use of the blue netting enhanced the biosynthesis of phenolics, whereas the use of the red netting increased the antioxidant activity of spinach baby leaves. ...
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... Producing about 18.1 ton ha−1 of spinach in 2017 (Casierra-Posada et al. 2021). Which may be associated to the growing awareness of healthier lifestyles based on plantbased diets and alertness of chronic diseases associated to unhealthy nutritional habits, e.g., cardiovascular problems, overweight, cancer to name but a few (Fan et al. 2014;Lara et al. 2021). ...
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Phytochromes are the best characterized and most frequently studied plant photoreceptors. A plethora of studies have revealed important roles for phytochromes in plant development, and more recently, evidence indicates that these photoreceptors also modulate responses to a multitude of abiotic and biotic stresses. Thus, the present work aimed to investigate whether tomato phytochromes phyA, phyB1 and phyB2 are involved with responses to low water potential (polyethylene glycol 6000 at Ψw of −0.3 MPa), high salinity (100 mM NaCl), cadmium contamination (65 mM CdCl2), high temperature (42 °C for six hours during three days) and ultraviolet B radiation (UV-B − 280–320 nm for eight hours during three days) stresses. For this purpose, seedlings of tomato mutants impacted by phytochrome A (fri), phytochrome B1 (tri) and phytochrome B2 (phyB2) were subjected to abiotic stresses and evaluated for their growth, pigment and osmoprotectant accumulation and lipid peroxidation. Under the conditions of this study, the results did not shown large variations of phyA mutant when compared to the wild genotype. However, the tomato phytochromes B1 and B2 mainly act as negative regulators of growth, pigment maintenance and osmoprotectant accumulation during responses to the different abiotic stresses.
Article
Modification of spectral quality via colored shade nets can act as a physiological tool to modify the crop microenvironment and advance plant growth and yield. This literature review presents data on the physiological responses in vegetables linked to light quality under different coloured shade nets. The physiological parameters discussed in the review include: vegetable growth parameters (leaf area, leaf chlorophyll), tissue structure, fruit ripening, physiological disorders, pest and disease incidence, fruit quality parameters (soluble solids content and titratable acidity), phytochemicals (antioxidant activity, ascorbic acid, carotenoid and flavonoid contents) and aroma volatile compounds at harvest. Also, it is evident in the reviewed literature that light quality influences the biosynthesis, accumulation and retention of vegetable phytochemicals, as well as the decay development during storage. These new strategies to modulate light quality should be conveyed to vegetable producing farmers, thus allowing them to preserve the freshness and post-harvest quality of vegetables for an extended period of time, and to meet the consumers demand for vegetables with high nutritional value all year round. Research on light manipulation in horticultural systems is necessary for a sustainable and market-oriented open field and greenhouse vegetable production in the future.
Article
Green leafy vegetables available in Sri Lanka have not been fully exploited, although they are stipulated to be rich sources of natural antioxidant. This study examined the antioxidant properties of thirty four edible green leafy vegetables popular in Sri Lanka. Methanolic extracts of leafy vegetables were analysed for total phenolic, carotene and chlorophyll content, and were evaluated for total antioxidant capacity, reducing power, lipid peroxidation and DPPH radical scavenging assays. The results indicated that these leafy vegetables have remarkable variations in their antioxidant activities. Among the plant materials screened for their antioxidant properties, Sesbania grandiflora, Cassia auriculata, Murraya koenigii Spreng, Passiflora edulis, Gymnema lactiferum and Olax zeylanica showed high carotene content, antioxidant activities and polyphenolics compared to other leaf varieties tested. A good correlation was observed between antioxidant assays and polyphenolics of the leafy vegetables. Keywords Green leafy vegetables; Polyphenolics; Antioxidant activities; Reducing power; Carotene
Article
The influence of spectral light on leaf quality and phytochemical contents and composition of aroma compounds in coriander leaves grown for fresh use under photo-selective nets; pearl net [40% shading; and 3.88 blue/red ratio; 0.21 red/far red ratio; photosynthetic radiation (PAR) 233.24 (μmol m− 2 s− 1)] and red net [40% shading and 0.57 blue/red ratio; 0.85 red/far red ratio; 221.67 (μmol m− 2 s− 1)] were compared with commercially used black nets [25% shading; 3.32 blue/red ratio 0.96 red/far red ratio; 365.26 (μmol m− 2 s− 1)] at harvest and after 14 days of storage.
Article
The nutritional composition of ten leafy vegetables (chicory, green lettuce, lamb’s lettuce, mizuna, red chard, red lettuce, rocket, spinach, Swiss chard, and tatsoi) and quality traits of the selected leafy vegetables in relation to the light intensity (low and high Photosynthetically Active Radiation; PAR) at time of harvest were determined. Irrespective of the light intensity at time of harvest, the highest leaf dry matter (DM), proteins, nitrate, P, K and Ca contents were observed in rocket followed by mizuna. The highest lipophilic antioxidant activity (LAA) was recorded in red lettuce and rocket, whereas ascorbic acid (AA) and total phenolic (TP) contents of red lettuce were higher compared to the other leafy vegetables. When leafy vegetables were harvested at low as opposed to high PAR, the leaf content was higher in DM, protein, K, Ca and Mg, hydrophilic antioxidant activity (HAA), and LAA by 12.5%, 10.0%, 12.6%, 23.7%, 14.1%, 11.9%, and 18.5%, respectively. The highest values in TP for chicory, green lettuce, lamb’s lettuce, mizuna, red chard, and red lettuce, were observed under high PAR.
Article
Colored shade nets (photo-selective nets - ChromatiNets), which have been developed during the last decade to filter selected spectral regions of sunlight, concomitantly with inducing light scattering, are designed to specifically modify plant attributes such as more fruits on the plants and higher yield. In studies conducted during the last two years on two cultivars of red sweet bell pepper (Capsicum annuum); 'Romans' and 'Vergasa', we have found that peppers grown in semi-arid region under the Pearl and Yellow shade nets, significantly maintained better fruit quality after 15 d storage at 7°C plus 3 d shelf life simulation, compared to the traditional black shade net, or the Red shade net of equivalent shading capacity (35%). Most prominently, the Pearl and Yellow nets significantly reduced decay incidence in both cultivars during the two years, compared to the Black and Red shade nets. The main decay-causing agent was Alternaria alternata. Results have shown a significant reduction in Alternaria spp. population in the field, under both Pearl and Yellow nets as evaluated by selective growing medium. Red shade net significantly reduced fruit weight loss, compared to the other shade nets, but other quality parameters such as firmness, elasticity and sugar level have not been affected by the colored shade nets.
Article
In this study, we determined the effects of raising seedlings with different light spectra such as with blue, red, and blue + red light-emitting diode (LED) lights on seedling quality and yield of red leaf lettuce plants. The light treatments we used were applied for a period of 1 week and consisted of 100 μmol.m-2.s-1 of blue light, simultaneous irradiation with 50 mmol.m-2.s-1 of blue light and 50 mmol.m-2.s-1 of red light, and 100 mmol.m-2.s-1 of red light. At the end of the light treatment, that is 17 days after sowing (DAS), the leaf area and shoot fresh weight (FW) of the lettuce seedlings treated with red light increased by 33% and 25%, respectively, and the dry weight of the shoots and roots of the lettuce seedlings treated with blue-containing LED lights increased by greater than 29% and greater than 83% compared with seedlings grown under a white fluorescent lamp (FL). The shoot/root ratio and specific leaf area of plants irradiated with blue-containing LED lights decreased. At 45 DAS, higher leaf areas and FWs were obtained in lettuce plants treated with blue-containing LED lights. The total chlorophyll (Chl) contents in lettuce plants treated with blue-containing and red lights were less than that of lettuce plants treated with FL, but the Chl a/b ratio and carotenoid content increased under blue-containing LED lights. Polyphenol contents and the total antioxidant status (TAS) were greater in lettuce seedlings treated with blue-containing LED lights than in those treated with FL at 17 DAS. The higher polyphenol contents and TAS in lettuce seedlings at 17 DAS decreased in lettuce plants at 45 DAS. In conclusion, our results indicate that raising seedlings treated with blue light promoted the growth of lettuce plants after transplanting. This is likely because of high shoot and root biomasses, a high content of photosynthetic pigments, and high antioxidant activities in the lettuce seedlings before transplanting. The compact morphology of lettuce seedlings treated with blue LED light would be also useful for transplanting.
Article
Fresh-cut spinach during processing undergoes several mechanical procedures such as cutting, which may induce stress responses. These stresses may trigger the accumulation of harmful reactive oxygen species (ROS). Plants respond through a wide range of mechanisms and ascorbic acid (AsA) has an important role. The combined effect of cutting, temperature and storage time on AsA recycling route in spinach fresh-cut leaves was studied. AsA, gene expression and activities of the enzymes involved in the AsA oxidation and recycling were considered. Spinach leaves were cut in six pieces and stored at 4 °C or 20 °C. AsA content and enzymes activities were measured over six days of storage, while gene expression analyses were performed in a time-point experiment within 24 h after cutting. Results showed that AsA decreased after cutting (from 19.41 mg/100 g FW to 15 mg/100 g FW) and generally was higher in samples stored at 4 °C. After six days, AsA was 10 mg/100 g in control and 5 mg/100 g FW in cut leaves. The expression of genes and activities of the enzymes involved in the AsA oxidation and recycling route were, for some enzymes, in accordance with AsA levels. The APX (EC 1.11.1.11) activity after cutting increased up to 290 nmol AsA mg−1 prot min−1 compared to the control with 190 nmol AsA mg−1 prot min−1. AsA reduction is firstly affected by temperature and aggravated by cutting procedures. AsA represents a valuable postharvest quality indicator of freshness in spinach leaves.
Article
Pyropheophytins a and b were determined as predominant chlorophyll derivatives in heat processed spinach. Chlorophylls a, b, pheophytins a, b and pyropheophytins a, b were quantitated in fresh, blanched and heat processed spinach at 116, 121 and 126°C. First order degradation rate constants were determined to calculate activation energies of 25.2 and 22.5 Kcal/mole for chlorophylls a and b and 20.7 and 15.7 Kcal/mole for pheophytins a and b, respectively. Based on the results, the suggested mechanism for the decomposition of chlorophyll during heat processing of vegetables is: Chlorophyll Pheophytin Pyropheophytin. Pyropheophytins a and b were major chlorophyll degradation products found in all commercially canned vegetable products surveyed.
Article
Flavonoids are important in plant interactions with the environment and may have positive effects on human health. Effects of light quality and quantity on flavonoid concentration were studied in baby spinach (Spinacia oleracea L.) cultivated under three types of shade netting differing in transmittance of UV-B and PAR, at two times during the season. Leaves harvested at two growth stages for each sowing were subjected to different post-harvest storage conditions. Shade nettings had a relatively small effect on flavonoid concentration in baby spinach. The largest effect was found when radiation was most intense. The nettings then decreased total flavonoid concentration by 15–24% at the normal commercial growth stage at harvest. Radiation and plant growth both affected flavonoid concentration, in opposite or similar directions depending on time of season. This variation was reflected in the statistical analysis, showing significant interactions among the factors. There were large differences (up to 100%) in flavonoid concentration between the different times of the season, in shaded as well as unshaded spinach. Flavonoid concentration and composition changed during storage, but no consistent difference was found between the shaded and unshaded leaves. In most cases, total flavonoid concentration increased significantly during the first 6 days of storage. In conclusion, the use of shade netting is acceptable for production of baby spinach as regards flavonoid concentration and composition. Copyright © 2007 Society of Chemical Industry
Article
This review describes the biochemical bases for color and firmness changes in fruit and vegetable tissues, since appearance and texture are two of the most fundamental factors affecting the quality of fresh-cut products. The intent is to provide a level of understanding that can be used to underpin future research directions in order to resolve existing issues that limit fresh-cut quality and shelf life. The biochemical mechanisms for enzymatic browning mediated by polyphenol oxidase and phenol peroxidase are described, and the importance of limiting cellular damage during the processing of fresh-cut fruit and vegetable products is emphasized. Also described are two mechanisms of chlorophyll degradation involved in discoloration events in green tissues, and examples of coloring processes specific to particular crops (white blush in carrots, discoloration of Allium spp., secondary browning in apples). The loss of desirable texture in fresh-cut products is a major problem. In fruit this is largely due to a continuation of cell wall disassembly events that are a normal component of ripening, and which result in declining cell wall strength and reduced intercellular adhesion. In some species the process is exacerbated by wound-response ethylene. However, wounding, water loss and ripening-related turgor changes are also important contributors to textural deterioration. In fresh-cut vegetables, water loss and damage-induced lignification are common problems. The effects of factors such as maturity at harvest, processing conditions and various treatments to mitigate quality decline are discussed.
Article
The antiradical activities of various antioxidants were determined using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH*). In its radical form. DPPH* has an absorption band at 515 nm which dissappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPH* and shown to follow one of three possible reaction kinetic types. Ascorbic acid, isoascorbic acid and isoeugenol reacted quickly with the DPPH* reaching a steady state immediately. Rosmarinic acid and δ-tocopherol reacted a little slower and reached a steady state within 30 min. The remaining compounds reacted more progressively with the DPPH* reaching a steady state from 1 to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometry of 4 to 6 reduced DPPH* molecules per molecule of antioxidant. Vanillin, phenol, γ-resorcylic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry for the other 13 phenolic compounds varied from one to three reduced DPPH* molecules per molecule of antioxidant. Possible mechanisms are proposed to explain the experimental results.
Article
This work investigates the effect of leaf age (young, fully expanded and mature leaves) as well as storage temperature (0, 5 and 10 °C) on color, chlorophyll content, yellowing, composition, CO2 and ethylene production of rocket (Eruca sativa Mill.) leaves. Leaf age had a significant effect on the levels of soluble solids, total soluble phenols and nitrates and on the metabolic activity (CO2 and ethylene production) of rocket at harvest as well as on the postharvest ethylene production. However, this last effect was not important for the postharvest quality of rocket leaves. Chlorophyll degradation was the most serious postharvest alteration in rocket leaves resulting in yellowing. This process was significantly retarded at the lower storage temperatures, probably due to reduced overall metabolic activity. It is concluded that rocket leaves can be stored successfully at 0 °C with a maximum storage life of 16 days, while at 5 °C slight quality deterioration was observed and shelf-life was reduced by 3 days. At 10 °C, rocket leaves deteriorated rapidly and their shelf-life was only 8 days.
Article
The effects of water blanching, freezing, and frozen storage during 400 days at three different temperatures (−7, −15 and −30 °C), on watercress (Nasturtium officinale R. Br.) colour Hunter Lab parameters, chlorophyll degradation, vitamin C content loss and peroxidase (POD) activity were evaluated. The blanching induced significant changes on colour values and chlorophylls and vitamin C contents. POD activity was reduced 85% from its initial value. Freezing did not affect chlorophylls and vitamin C levels, however, promoted significant differences in colour values and POD residual activity. During frozen storage, ascorbic acid (AA) and POD activity degradations followed first-order kinetics, and colour parameters (LH · aH · bH, −aH/bH, LH · aH/bH, LH/aH · bH and hue ()) were successfully described by zero-order kinetics. The storage temperature effect was successfully described by the Arrhenius law. Chlorophylls and dehydroascorbic acid (DHAA) contents were kept constant during frozen storage.
Article
Water deficit and salinity, especially under high light intensity or in combination with other stresses, disrupt photosynthesis and increase photorespiration, altering the normal homeostasis of cells and cause an increased production of reactive oxygen species (ROS). ROS play a dual role in the response of plants to abiotic stresses functioning as toxic by-products of stress metabolism, as well as important signal transduction molecules. In this review, we provide an overview of ROS homeostasis and signalling in response to drought and salt stresses and discuss the current understanding of ROS involvement in stress sensing, stress signalling and regulation of acclimation responses.
Article
A simple, automated test measuring the ferric reducing ability of plasma, the FRAP assay, is presented as a novel method for assessing "antioxidant power." Ferric to ferrous ion reduction at low pH causes a colored ferrous-tripyridyltriazine complex to form. FRAP values are obtained by comparing the absorbance change at 593 nm in test reaction mixtures with those containing ferrous ions in known concentration. Absorbance changes are linear over a wide concentration range with antioxidant mixtures, including plasma, and with solutions containing one antioxidant in purified form. There is no apparent interaction between antioxidants. Measured stoichiometric factors of Trolox, alpha-tocopherol, ascorbic acid, and uric acid are all 2.0; that of bilirubin is 4.0. Activity of albumin is very low. Within- and between-run CVs are <1.0 and <3.0%, respectively, at 100-1000 micromol/liter. FRAP values of fresh plasma of healthy Chinese adults: 612-1634 micromol/liter (mean, 1017; SD, 206; n = 141). The FRAP assay is inexpensive, reagents are simple to prepare, results are highly reproducible, and the procedure is straightforward and speedy. The FRAP assay offers a putative index of antioxidant, or reducing, potential of biological fluids within the technological reach of every laboratory and researcher interested in oxidative stress and its effects.
Colored Shade Cloth Affects the Growth of Basil
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Guía de Laboratorio curso: Evaluación Sensorial de los alimentos
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Araya, E., 2007. Guía de Laboratorio curso: Evaluación Sensorial de los alimentos. Universidad de Chile, Facultad de Ciencias Agronómicas Departamento de Agroindustria y Enología, 81 p.
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Coloured shade nets can improve the yield and quality of green decorative branches of Pittosporum variegatum
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Lechuga hidrópica: Nutrición Mineral
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Light quality manipulation improves vegetable quality at harvest and postharvest: a reciew
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