Quality Of Spinach Research Articles

Identification of spinach SIAMESE and analysis of its function in plant immunity

Diseases cause a significant loss in both yield and quality of spinach. The cell cycle signalling pathway plays a central role in balancing development and immunity of plants. Cyclin-Dependent Kinase Inhibitor (CKI) is a core cell cycle regulator. It has been found that two Arabidopsis CKIs, SIAMESE (SIM) and SMR1 (SIAMESE-Related 1), function redundantly not only as negative regulators of cell proliferation but also as positive regulators of plant immunity. In the spinach genome, we identified a homologue of Arabidopsis SIM, referred to as Spinacia oleracea SIAMESE (SoSIM). To investigate the function of SoSIM, we introduced the 35S promoter-driven SoSIM (35S:SoSIM) into Arabidopsis sim smr1 double mutants. Over-expression of SoSIM phenocopied RNA interference of Cyclin-Dependent Kinase A1 (CDKA1) which exhibited dwarf and serrated leaves, confirming that SIM is a CDK inhibitor. Arabidopsis wild-type trichomes are single and unicellular, whereas sim smr1 mutant trichomes are clustered and multicellular. SoSIM restored wild-type trichome phenotype of sim smr1 mutant. The sim smr1 mutants were susceptible to the avirulent pathogen Pseudomonas syringae pv. maculicola as compared with wild-type plants. Our data showed that the resistance of 35S:SoSIM-transgenic sim smr1 lines to the pathogen was fully restored, indicating that SoSIM activates plant immunity. These data verify that SoSIM functions as its Arabidopsis counterpart in inhibition of plant development and activation of plant immunity. Therefore, SoSIM can be explored to control the balance between development and immunity in spinach.

Effect of Sowing Dates and Number of Cuttings on Yield and Quality of Spinach (Spinacia oleraceae L.)

Two field experiments were carried out in clay loam soil at Experimental farm, Baramon, Dakahlia Governorate during the two winter seasons of 2010/11 and 2011/12 to investigate the effect of four sowing dates (15 Oct., 1 Nov., 15 Nov. and 1 Dec.) and three harvesting patterns (without cutting C0, one cutting C1 and two cuttings C2) as well as their interaction on yield and quality of spinach cv. Balady. The experiments were laid out in a split plot design with three replicates where sowing dates were the main factor and the number of cuttings was the secondary factor. The obtained results indicated that sowing date at mid October followed by first of November promoted vegetative growth characters, which showed a significant increase in plant height, number of leaves/plant and average leaf area. In addition, early sowing at mid October and first of November produced the greatest fresh foliage weight/plant, fresh yield and total fresh yield. Moreover, early sowing dates increased dry matter content in spinach leaves but showed the least values for total chlorophyll content. Harvesting spinach plants without cutting led to an increase in plant height and average leaf area, whereas the second cutting exhibited the largest number of leaves/plant. Harvesting plants without cutting showed the largest means of plant height, average leaf area, foliage fresh foliage weight/plant and fresh yield, while total fresh yield was increased by cutting spinach plants twice. The interaction between sowing dates and number of cuttings showed significant differences for all studied characters in both seasons of the study. Generally, it could be concluded that the suitable treatment to maximize spinach yield was sowing spinach at mid October or first of November and cut plants twice. Otherwise, delaying sowing date causes a reduction in vegetative growth and consequently total yield production

Short-term Effects of Composted Cattle Manure or Cotton Burr on Growth, Physiology, and Phytochemical of Spinach

Compost is increasingly used in horticultural crop production as soil conditioner and fertilizer because of its contribution to agriculture sustainability. The short-term (35 days after transplanting) effects of composted cattle manure or cotton burr on growth, physiology, and phytochemical of spinach (Spinacia oleracea L.) were evaluated in a greenhouse. Composted cattle manure at 5% or 10% mix rate (5Ca or 10Ca) greatly enhanced spinach growth as indicated by increased leaf number, area, fresh and dry weights (FW and DW), shoot FW and DW, and root DW. They also increased water use efficiency (WUE) and shoot:root ratio, and improved the photochemistry of mature leaves. Chlorophyll content also increased under 10Ca treatment. Composted cotton burr also improved spinach growth but only at 10% amendments (10Co), and was less efficient than composted cattle manure. Specific leaf area (SLA) decreased and succulence increased under all compost amendment indicating that compost could improve spinach quality. All soil amendments reduced the content of total phenolic and anthocyanin, while only 10Co and 5Ca treatments decreased flavonoid content and total antioxidant capacity. The content of carotenoid and protein increased in 10Ca treatment and amino acid content increased under both 5Ca and 10Ca treatments. The results indicated that compost, especially composted cattle manure mixed at 10%, improved spinach production and quality, and with proper application rate enhanced nutritional value by increasing carotenoid, protein, and amino acid contents while having little effect on total antioxidant capacity.

Gaseous ozone treatment of baby spinach within the existing production chain for inactivation of Escherichia coli O157:H7

Sanitization of fresh fruits and vegetables, particularly leafy greens, is limited by penetration of sanitizers to the location of internalized pathogens. It is necessary, therefore, to adapt sanitization operations to practices in the existing produce chain. In this work, we investigated experimentally in a pilot scale, various potential sanitization options using gaseous ozone during and post vacuum cooling on the inactivation of Escherichia coli O157:H7 ATCC 43889. It was found that vacuum cooling causes bacterial internalization, making them harder to reach by sanitizer. However, the application of ozone during the vacuum cooling step significantly reduced (p < 0.05) population of viable internalized bacteria which otherwise remain unaffected by sodium hypochlorite and UV light surface treatments. The presence of free water inside the vessel available for evaporation during vacuum cooling was found to impact the microbial reduction during combined vacuum cooling and the gaseous ozone treatment. The efficacy of application of high ozone concentration (1.5 g/m3) short term during the vacuum cooling step in combination with low ozone concentration (0.032–0.528 g/m3) long term sanitization treatments (days) was evaluated. This combination of gaseous treatment was found more effective in microbial reduction compared to a single treatment with a strongly expressed synergistic effect. The post-treatment spinach quality evaluation, however showed an increasing degree of damage as the time of treatment increases even at low ozone concentrations.

Vermicompost Affects Soil Properties and Spinach Growth, Physiology, and Nutritional Value

The use of vermicompost to improve soil fertility and enhance crop yield has gained considerable momentum due to its contribution to agroecological sustainability. Short-term (35 days after transplanting) effects of vermicompost, applied either as a soil amendment (5% and 10%, v/v) or a drench (40 mL of vermicompost extract at 0, 14, 21, and 28 days after transplanting), on soil properties and spinach plants (Spinacia oleracea L.) were evaluated in a greenhouse. After harvesting, the amendments left high residual levels of nutrients, organic matter and carbon, and increased soil cation exchange capacity (CEC) and water-holding capacity (WHC). Drench treatment of unamended soil increased soil nutrients, CEC, and WHC. All vermicompost treatments, especially amendment at 10% rate, increased leaf number, area, fresh and dry weight (FW and DW), shoot FW and DW, root DW, and water use efficiency (WUE). Vermicompost increased leaf chlorophyll content, and photochemical efficiency, yield, and electron transport rate (ETR) of mature leaves, as well as increased leaf succulence, and carotenoid, protein, and amino acid content. Vermicompost soil amendment reduced phenolics and flavonoids, leading to lower antioxidant capacity, whereas drench treatment only decreased betacyanin content. Vermicompost improved soil fertility, prompted leaf production, delayed leaf senescence, and enhanced growth of spinach. It also favorably influenced spinach quality by increasing leaf succulence and carotenoid, protein, and amino acids content, although it, as soil amendment, reduced flavonoid content leading to low antioxidant capacity.

Effect of nitrogen fertilizer and growth stimulants on flowering behaviour , seed yield and its quality of spinach.

Effect of nitrogen fertilizer and growth stimulants on flowering behaviour , seed yield and its quality of spinach.

Effect of Processing on Nutritional Quality of Spinach (Spinacia oleracea

Effect of Processing on Nutritional Quality of Spinach (Spinacia oleracea

Effect of phosphorus and potassium levels on yield and quality of spinach

The present investigation on effect of P and K levels on yield and quality of spinach was carried out during Rabi season 2012-13 at College Garden, Department of Horticulture, College of Agriculture, Nagpur. The treatments were three levels of phosphorus viz. , 0 kg (P 0 ), 10 kg (P 1 ), 20 kg (P 2 ) and potassium viz. , 0 kg (K 0 ), 15 kg (K 1 ), 30 kg (K 2 ). The experiment was laid out in FRBD with three replications. The experimental soil was slightly calcareous, alkaline in reaction and clayey in texture. It was sufficient in potassium and low in organic carbon, available nitrogen and phosphorus. Among the quality parameters, the maximum leaf area (112.03 cm 2 and 111.84 cm 2 ), protein (10.97% and 11.21%), chlorophyll (1.93 and 1.98 mg g ?1 ), and ascorbic acid content (71.48 mg and 71.54 mg) were found in treatment which received phosphorus @ 20 kg ha ?1 and potassium @ 30 kg ha ?1 , respectively at harvesting.

Combined Effects of Water and Nitrogen on Growth, Biomass, and Quality of Spinach (Spinacia oleracea Linn.)

ABSTRACTWater scarcity and nitrate contamination have caused considerable attention to environmental matters. Water and nitrogen interactions have critical impacts on their use efficiency, plant growth, and quality. In a field experiment, a combination of three water treatments and three nitrogen rates was applied to determine their interactive effects on the growth of spinach. Soil water supply that was too low [W3N1 (the combination of water treatment 3 and nitrogen treatment 1), W3N2] could cause an increase in nitrate content. Oxalate contents would increase when water and nitrogen were either inadequate (W3N0, W3N1) or too high (W2N2). The most profit from spinach was obtained in plots that received water treatment 2 and nitrogen fertilizer 78 kg N ha−1. However, considering nitrogen treatments could affect the nitrate and oxalic acid, application of water treatment 2 and 39 kg N ha−1 nitrogen fertilizer could get better spinach quality.

Improving spinach quality and reducing energy costs by retrofitting retail open refrigerated cases with doors

The prevalence of open-refrigerated display cases is ubiquitous in retail supermarkets, even in the face of the non-uniform temperature conditions present in these cases. In this paper, the temperature variations (ΔT) of packaged ready-to-eat baby spinach were evaluated for an open display case and a display case with glass doors, in order to assess the advantages of this physical barrier in minimizing ΔT and decay rate, and improving the visual quality of the samples after four days of storage. The two 3.66m display cases were installed in the same room and conditions were constant at 21°C and 60–70% of relative humidity, with a thermostat setting for both cases set at 0.6°C. Results showed that the display case with doors significantly improved temperature uniformity and compliance with the U.S. Food and Drug Administration (FDA) Food Code recommendation of 5°C or less to prevent microbial pathogen growth in packaged leafy greens. Only 1% of the temperature readings over four days in the case with doors were non-compliant with the FDA Food Code, while 24% of the readings in the open case were non-compliant; mostly recorded by the front positions of the case. The lower temperatures and ΔT of the case with doors were consistent with the higher visual quality scores (P<0.001) for the baby spinach samples recorded by trained panelists, based on a 9-point hedonic scale, at 7.2 and 6.6 for the case with doors and the open case, respectively. Differences in decay rate were significant (P<0.001) by the front of the case, with mean values of 8.8% for the open case and 5.5% for the case with doors. Furthermore, operational energy costs were 69% less than the open display case and the cost of door retrofits can be recouped in less than two years by energy savings alone.

Inactivation of Escherichia coli O157:H7 in vitro and on the surface of spinach leaves by biobased antimicrobial surfactants

This study was conducted to evaluate the effect of biosurfactants on the populations of Escherichia coli O157:H7 in suspension and on spinach leaves. Eight surfactants including four soybean oil-based biosurfactants, sodium dodecyl sulfate (SDS), polyoxyethylene sorbitan monooleate (Tween 80), sophorolipid (SO) and thiamine dilauryl sulfate (TDS) at concentrations of 0.1%, 0.5% and 1.0% were tested in bacterial suspension, and the most effective biosurfactants were applied on spinach leaves. Results showed that the soybean oil-based biosurfactants, SDS or Tween 80 did not significantly affect E. coli O157:H7 populations. SO and TDS at concentrations of 1.0% were effective in reducing E. coli O157:H7 populations in bacterial suspension. E. coli O157:H7 with an initial population of 7.1 log CFU/mL was not detectable (detection limit: 1 log CFU/mL) after 1 min in 1.0% TDS or after 2 h in 1.0% SO. On spinach leaves, SO at 1% did not significantly affect E. coli when compared to a water wash during 7 days post-treatment storage at 4 °C. However, TDS (1.0%) wash was as effective as 200 ppm chlorine in reducing population of spot inoculated E. coli O157:H7, achieving 3.1 and 2.7 log CFU/per leaf at day 0, and 1.4 and 1.9 log CFU/leaf at day 7 when compared with a water wash. No apparent change in spinach visual quality was observed. None of treatments caused changes in visual quality of spinach. Electron micrographs suggested ultrastructural damage of bacterial cells such as separation of the outer membrane from the cytoplasmic membrane. Overall, our results showed that SO and TDS may be potential sanitizers in inactivating human pathogens such as E. coli O157:H7 in wash water and on fresh produce.

Quantitative Relationship of the Nutritional Quality of Spinach with Temperature and Duration in Root Area Chilling Treatment

Quantitative Relationship of the Nutritional Quality of Spinach with Temperature and Duration in Root Area Chilling Treatment

Effect of Nano-Zinc Oxide on the Leaf Physical and Nutritional Quality of Spinach

Spinach (Spinacia oleracea) belongs to family Amaranthaceae and is one of the important and nutritious leafy vegetable consumed in India. The pot culture experiment is carried out during 2014-15 to study the effect of nanozinc oxide particles on the leaf physical and nutritional traits of spinach. The spinach plants were sprayed with graded concentration of zinc oxide nanoparticles (ZnO NPs) after 14 days of sowing. The leaf physical parameters like leaf length, leaf width and leaf surface area are recorded at the time of maturity (45-50 days). The protein, carbohydrate, fat and dietary fiber content in leaf samples are determined. The plants sprayed with ZnO NPs at the concentration of 500 and 1000 ppm showed the increased leaf length, width, surface area and colour of leaf samples when compared to control leaf samples. Similarly treated plants with ZnO NPs at the concentration of 500 and 1000 ppm showed higher values of protein and dietary fibre content in comparison to control leaf samples of spinach. Hence our study suggests that the nano-zinc oxide sprayed spinach is more nutritious to vegetarian diet by providing, protein, fiber and required amount of vegetarian fat to diet.

First Report of Leaf Spot of Spinach Caused by Pleospora betae in Spain.

The production of spinach (Spinacia oleracea L.) in Spain has increased 50% since 2009, mainly due to the commercialization of fresh-cut spinach leaves packaged in modified atmosphere containers. In October 2012, light brown leaf spots 1 to 2 cm in diameter with dark concentric rings were observed in a commercial spinach production area in Valencia Province, Spain. The initial outbreak comprised an area of about 3 ha with a 20% disease incidence. Symptomatic leaves from spinach cv. Apollo were collected in the affected area and were surface disinfected with 0.5% NaOCl for 2 min. Small fragments from lesions were placed onto potato dextrose agar (PDA) amended with 0.5 g streptomycin sulfate/liter. Fungal colonies developed after 3 days of incubation at 23°C from about 90% of the infected tissues plated. Isolates were transferred to oatmeal agar (OA) (1) and water agar (WA) amended with autoclaved pea seeds (2). Plates were incubated for 30 days at 24°C with 13 h of fluorescent light and 11 h of dark for morphological examination. Colonies were olivaceous grey in OA and pycnidia developed in WA were globose to subglobose, olivaceous black, and 100 to 200 μm in diameter. Conidia were globose to ellipsoidal, hyaline, aseptate, and 3.8 to 7.7 × 2.4 to 3.9 μm. Swollen cells were observed. Isolates showed a positive reaction to NaOH (1). Partial 18S, ITS1, 5.8S, ITS2, and partial 28S ribosomal RNA (rRNA) regions were amplified using the primers ITS1 and ITS4 (4) and sequenced from DNA extracted from the isolate designated as IVIA-V004 (GenBank Accession No. KF321782). The sequence had 100% identity (e-value 0.0) with that of Pleospora betae (Berl.) Nevod. (syn. Phoma betae A.B. Frank) representative strain CBS 523.66 (1). Pathogenicity tests were performed twice by inoculating 4-month-old plants of spinach cv. Apollo, table beet (Beta vulgaris L.) cv. Detroit, and Swiss chard (B. vulgaris subsp. cicla) cv. Verde de Penca Blanca. Plants were inoculated by spraying a conidial suspension of isolate IVIA-V004 (10 ml/plant, 105 conidia/ml water) using a manual pressure sprayer. Plants were immediately covered with black plastic bags and incubated in a growth chamber at 23°C. In each experiment, four plants of each host were inoculated with the fungus and four additional plants sprayed with sterile distilled water were used as controls. Plastic bags were removed after 48 h and leaf spots similar to those observed in affected spinach plants in the field were visible on all spinach, table beets, and Swiss chard plants 3 to 5 days after inoculation. No symptoms were observed on control plants. Fungal colonies morphologically identified as P. betae were re-isolated from leaf lesions on inoculated plants, but not from asymptomatic leaves of control plants. To our knowledge, this is the first report of leaf spot caused by P. betae on spinach in Spain, where it was previously described affecting sugar beet (3). The disease reduces the quality of spinach leaves and proper control measures should be implemented.

Effect of Gamma Radiation on the Reduction of Salmonella strains, Listeria monocytogenes, and Shiga Toxin–Producing Escherichia coli and Sensory Evaluation of Minimally Processed Spinach (Tetragonia expansa)

This study evaluated the effects of irradiation on the reduction of Shiga toxin-producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10 -values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

Effects of Nitrogen and Calcium Nutrition Withdrawal Before Harvesting on Biomass and Nutritive and Safety Quality in Spinach (Spinacia Oleracea L.)

A hydroponic culture was used to study different nitrogen and calcium supply patterns on biomass, nutritive, and safety quality of spinach seven days before harvesting. The results showed that the complete or partial withdrawal of nitrogen (N) and calcium (Ca) nutrient decreased spinach biomass compared to control (CK). At the same time, the withdrawal of N and Ca supply before harvesting increased vitamin C contents and decreased nitrate and oxalate content in edible parts of spinach. The decrease in spinach biomass could be partially compensated by the increase of the nutritive and safety quality of spinach and the reduced use of N and Ca nutrients.

Kinetic study of quality indices and shelf life modelling of frozen spinach under dynamic conditions of the cold chain

A systematic kinetic study of quality loss of frozen spinach was conducted. Vitamin C, chlorophyll (a, b and total), colour, texture and sensory attributes were measured in frozen leafy spinach. Kinetic models of the selected quality indices were developed to determine the frozen spinach quality loss and calculate product remaining shelf life. Validated kinetic models of quality loss are applied in the evaluation, control and management of frozen spinach in the cold chain. Storage experiments were conducted at isothermal (−5, −8, −12, −18°C) and non-isothermal temperature conditions (Teff=−6.9°C) to validate proposed shelf life models. The temperature dependence of quality loss was adequately modelled by Arrhenius type equation and activation energy values of 132, 72, 43 and 61kJ/mol for vitamin C loss, total chlorophyll retention, texture deterioration and overall sensory scoring were calculated respectively. The shelf life at the reference temperature of −18°C ranged from 400 to 500days based on the different quality indices. The effects of temperature deviations were quantitatively evaluated and a realistic assessment of the frozen spinach remaining shelf life in the actual cold chain was conducted.

Spinach-irrigating and fertilizing for optimum quality, quantity, and economy

The increasing scarcity of water for irrigation and environmental pollution due to excessive use of fertilizers are the important problems in vegetable production. A field experiment with combination of three levels of irrigation and nitrogen fertilization was employed to optimize the irrigation and nitrogen fertilizer usage of spinach. Traits, yields, quality, and economic factors of spinach under different regimes were determined. The yield was the highest when spinach was grown under the condition of the soil water content at 16.5% combined with 170 kg ha−1 of nitrogen fertilizer, while the lowest yield was recorded for the one under the soil water content at 12.5% with 0 kg ha−1. Nitrate and oxalate contents of spinach were highly dependent on levels of irrigation and nitrogen fertilization. Nitrogen fertilization significantly decreased nitrogen use efficiency. Both water use efficiency and profit responded positively to increased nitrogen fertilizer usage. To optimize the quality and earnings of spinach, and consider the fact that nitrogen fertilizer could degrade the quality of spinach, application of the nitrogen fertilizer at 85 kg ha−1 and maintenance of the soil water content at 16.5% could be recommended for spinach cultivation under field conditions. Therefore, the findings in this present study are important to improve our knowledge of the irrigation and fertilization for the sustainable agriculture.

Pre-harvest treatment of spinach with Ascophyllum nodosum extract improves post-harvest storage and quality

Fresh spinach (Spinacia oleracea L.) leaves contain high concentrations of beneficial phytochemicals. However, spinach does not store well and is highly perishable especially during handling and post-harvest storage. In this study, we investigated the effect of pre-harvest root-treatment of spinach with Ascophyllum nodosum extract (ANE) at different concentrations (0, 0.1, 1.0, or 5.0gL−1) on post-harvest quality of fresh-cut spinach over a 35-day storage period. At the time of harvest there was no significant difference in dry weight, chlorophyll, ascorbate and lipid peroxidation between ANE-treated and non-treated plants. However, the loss in fresh weight and visual quality (color and turgor) of spinach leaves during storage was reduced by pre-harvest application of ANE. Lipid peroxidation was significantly reduced in ANE-treated leaves. The total chlorophyll content and ascorbate content in the control and treated leaves was however identical over the storage period and decreased at a similar rate. A negative correlation was observed between visual quality and lipid peroxidation. The results show that pre-harvest ANE application through root drench, especially at 1.0gL−1, enhanced post-harvest storage quality of spinach leaves.

Temperature determines post-harvest quality of spinach leaves after gamma irradiation

The relative importance of radiation dose, storage time, and temperature in radiation processing of spinach (Spinacia oleracea L.), was evaluated in terms of the postharvest quality through a model study using leaf disks. Physiological activity and chlorophyll and carotenoid contents were measured to represent the postharvest quality (in terms of external appearance) of spinach, a leafy green vegetable. At <TEX>$22^{\circ}C$</TEX> and <TEX>$30^{\circ}C$</TEX>, the higher gamma-radiation dose caused a greater decrease in the physiological activity, depending on the storage time of 4 d. However, this decrease was not significant at <TEX>$4^{\circ}C$</TEX> and <TEX>$15^{\circ}C$</TEX>. Total chlorophyll and carotenoid contents were substantially decreased by 3 kGy at <TEX>$15^{\circ}C$</TEX>, and dose-dependently by 0.5-3 kGy at <TEX>$22^{\circ}C$</TEX>. In contrast, the proportion of lutein in total carotenoid was significantly increased in the 2-3-kGy samples only at <TEX>$22^{\circ}C$</TEX>, while that of <TEX>${\beta}$</TEX>-carotene was slightly decreased, indicating progression of leaf aging. These data suggest that the unfavorable effect of gamma irradiation on the postharvest quality of spinach could be avoided or controlled by the storage time or temperature rather than the radiation dose. The current study could be available to improve radiation processing of other leafy green vegetables.