Potassium nutrition as a strategy to mitigate salt stress in melon grown under protected cultivation / Nutrição potássica como estratégia mitigadora do estresse salino em melões em cultivo protegido

The use of saline water is one of the major challenges of agriculture, as it can cause nutritional imbalances and thus reduce crop yield. This study proposes to examine the efficiency of potassium nutrition asa salt stress-mitigating agent in melon grown in a protected environment. The experiment was laid outin a randomized-block design with ten treatments in a 2 × 4 factorial arrangement represented by two melon cultivars (McLaren and SV1044MF) and four nutrient solutions (S1 - standard nutrient solution, 2.5 dS m-¹; S2 - nutrient solution salinized with NaCl, 5.0 dS m-¹; S3 - nutrient solution salinized with NaCl + 50% K, 6.5 dS m-¹; and S4 - nutrient solution salinized with NaCl + 100% K, 7.5 dS m-¹). Yield (average fruit weight, production, fruit diameter, internal cavity, and pulp thickness), quality (pulp firmness, total sugars, soluble solids [SS], vitamin C, pH, titratable acidity [TA] and SS/TA ratio) and nutritional (K, Na and K/Na ratio) variables were evaluated. Plants fertigated with standard nutrient solution showed the highest values for fruit weight (1,190.6 g), production (2,381.3 g per plant), fruit diameter (13.6 cm) and pulp thickness (2.6 cm) Cultivar McLaren produced heavier fruits (931.4 g) with larger diameter (12.4 cm) and pulp thickness (2.4cm). The addition of NaCl to nutrient solution induced a reduction in the yield variables but did not influence fruit quality. The addition of extra K to salinized nutrient solution did not mitigate the deleterious effect of salinity on the yield of melon.

O uso de água salina é um dos principais desafios na produção agrícola, pois pode provocar desbalanço nutricional e, consequentemente, reduzir o rendimento das culturas. Este trabalho teve como objetivo avaliar a eficiência da nutrição potássica como agente atenuador do estresse salino no meloeiro cultivado em ambiente protegido. O delineamento experimental utilizado foi em blocos casualizados, com dez tratamentos arranjados em esquema fatorial 2 × 4, sendo dois cultivares de meloeiro (McLarene SV1044MF) e quatro soluções nutritivas (S1- solução nutritiva padrão, 2,5 dS m-¹; S2 – solução nutritiva salinizada com NaCl, 5,0 dS m-¹; S3 – solução nutritiva salinizada com NaCl + 50% K, 6,5 dS m-¹; S4 - solução nutritiva salinizada com NaCl + 100% K, 7,5 dS m-¹). As variáveis de rendimento (peso médio de fruto, produção, diâmetro de fruto, cavidade interna e espessura de polpa), qualidade (firmeza de polpa, açúcares totais, sólidos solúveis, vitamina C, pH, acidez titulável e razão SS/AT) e nutrição (K, Na e razão K/Na) foram avaliadas. Plantas fertirrigadas com solução nutritiva padrão apresentaram maiores valores para peso de frutos (1.190,6 g), produção (2.381,3 g planta-¹), diâmetro de fruto (13,6 cm) e espessura de polpa (2,6 cm). O cv. McLaren apresentou frutos mais pesados (931,4 g), com maior diâmetro (12,4 cm) e espessura de polpa (2,4 cm). A adição de NaCl na solução nutritiva provocou redução nas variáveis de rendimento, mas não influenciou a qualidade dos frutos. A adição extra de K em solução nutritiva salinizada não atenuou o efeito deletério da salinidade sobre o rendimento do meloeiro.

Potassium nutrition as a strategy to mitigate salt stress in melon grown under protected cultivation / Nutrição potássica como estratégia mitigadora do estresse salino em melões em cultivo protegido

The use of saline water is one of the major challenges of agriculture, as it can cause nutritional imbalances and thus reduce crop yield. This study proposes to examine the efficiency of potassium nutrition asa salt stress-mitigating agent in melon grown in a protected environment. The experiment was laid outin a randomized-block design with ten treatments in a 2 × 4 factorial arrangement represented by two melon cultivars (McLaren and SV1044MF) and four nutrient solutions (S1 - standard nutrient solution, 2.5 dS m-¹; S2 - nutrient solution salinized with NaCl, 5.0 dS m-¹; S3 - nutrient solution salinized with NaCl + 50% K, 6.5 dS m-¹; and S4 - nutrient solution salinized with NaCl + 100% K, 7.5 dS m-¹). Yield (average fruit weight, production, fruit diameter, internal cavity, and pulp thickness), quality (pulp firmness, total sugars, soluble solids [SS], vitamin C, pH, titratable acidity [TA] and SS/TA ratio) and nutritional (K, Na and K/Na ratio) variables were evaluated. Plants fertigated with standard nutrient solution showed the highest values for fruit weight (1,190.6 g), production (2,381.3 g per plant), fruit diameter (13.6 cm) and pulp thickness (2.6 cm) Cultivar McLaren produced heavier fruits (931.4 g) with larger diameter (12.4 cm) and pulp thickness (2.4cm). The addition of NaCl to nutrient solution induced a reduction in the yield variables but did not influence fruit quality. The addition of extra K to salinized nutrient solution did not mitigate the deleterious effect of salinity on the yield of melon.(AU)

O uso de água salina é um dos principais desafios na produção agrícola, pois pode provocar desbalanço nutricional e, consequentemente, reduzir o rendimento das culturas. Este trabalho teve como objetivo avaliar a eficiência da nutrição potássica como agente atenuador do estresse salino no meloeiro cultivado em ambiente protegido. O delineamento experimental utilizado foi em blocos casualizados, com dez tratamentos arranjados em esquema fatorial 2 × 4, sendo dois cultivares de meloeiro (McLarene SV1044MF) e quatro soluções nutritivas (S1- solução nutritiva padrão, 2,5 dS m-¹; S2 solução nutritiva salinizada com NaCl, 5,0 dS m-¹; S3 solução nutritiva salinizada com NaCl + 50% K, 6,5 dS m-¹; S4 - solução nutritiva salinizada com NaCl + 100% K, 7,5 dS m-¹). As variáveis de rendimento (peso médio de fruto, produção, diâmetro de fruto, cavidade interna e espessura de polpa), qualidade (firmeza de polpa, açúcares totais, sólidos solúveis, vitamina C, pH, acidez titulável e razão SS/AT) e nutrição (K, Na e razão K/Na) foram avaliadas. Plantas fertirrigadas com solução nutritiva padrão apresentaram maiores valores para peso de frutos (1.190,6 g), produção (2.381,3 g planta-¹), diâmetro de fruto (13,6 cm) e espessura de polpa (2,6 cm). O cv. McLaren apresentou frutos mais pesados (931,4 g), com maior diâmetro (12,4 cm) e espessura de polpa (2,4 cm). A adição de NaCl na solução nutritiva provocou redução nas variáveis de rendimento, mas não influenciou a qualidade dos frutos. A adição extra de K em solução nutritiva salinizada não atenuou o efeito deletério da salinidade sobre o rendimento do meloeiro.(AU)

Cucumis melo pectin as potential candidate to control herpes simplex virus infection.

The herpes simplex virus, also known as HSV, is an important human pathogen. Acyclovir (ACV) is the first-line antiviral for the treatment of HSV infections; nevertheless HSV resistance to ACV has been increasingly reported and, therefore, search for alternative drugs have been encouraged. Herein, the effect of Cucumis melo sulfated pectin (SPCm) was evaluated in the HSV-1 infection. Pectin cytotoxicity and its antiherpetic action were determined by assays of MTT and plaque reduction, respectively. The SPCm concentration that reduced the cell viability by 50% (CC50) was 1440 µg/mL, while the concentration that reduced PFU in 50% (IC50) was 6 µg/mL against ACV-sensitive (KOS) strain and 12 µg/mL for ACV-resistant (AR-29) strain. The pectin showed high selectivity index (SI) for both viral strains. Therefore, we suggest that SPCm has been effective for HSV-1, strenghten by viral protein and DNA syntheses inhibition. In conclusion, we have found that SPCm is a promising alternative compound to control HSV infection.

Antioxidant stability enhancement of carotenoid rich-extract from Cantaloupe melon (Cucumis melo L.) nanoencapsulated in gelatin under different storage conditions.

The study evaluated the potential and antioxidant stability of nanoencapsulated carotenoid-rich extract (CE) from Cantaloupe melon (EPG). DPPH and ABTS radical scavenging assays were used to investigate the nanoencapsulation effect on antioxidant potential. CE and EPG stability were evaluated at 25 °C and 5 °C, with and without light (1600 lx) for 60 days, determining the ß-carotene concentration by UHPLC and antioxidant potential by ABTS. The antioxidant potential of carotenoids increased after nanoencapsulation (57-59%). After 60 days, there was low retention of ß-carotene (0-43.6%) in the CE, mainly at 25 °C light (0.00%) and dark (10.0%), and total loss of activity in the four conditions. EPG preserved the ß-carotene concentration in the dark at 25 °C (99.0%) and in the light (83.1%) and dark (99.0%) at 5 °C, maintaining the antioxidant potential (68.7-48.3%). Therefore, EPG enhanced and stabilized the antioxidant potential of carotenoids, beneficial to human health.

From seed to flour: Sowing sustainability in the use of cantaloupe melon residue (Cucumis melo L. var. reticulatus).

Reduction of waste from food industry and food services is a current concern due to the large amount of waste generated, including peels and fruit seeds. The objective of this study was to obtain a flour produced from Cantaloupe melon seeds (Cucumis melo L. var. reticulatus) and to evaluate the viability of using the product as an ingredient in cake manufacturing. In this study, different formulations were developed: standard cake-0% (F1) and cakes containing melon seed flour as substitute of wheat flour in 10% (F2), 30% (F3), and 50% (F4) concentrations. Centesimal composition, dietary fibre, structural and morphological characterization, determination of mineral composition, and evaluation of fatty acids profile in melon seed flour were carried out. To determine the overall acceptance of cake formulations, sensory analysis was performed with 135 non-trained panelists, which also included the identification of sensorial attributes using the Just About Right ideal scale test. The results showed that the melon seed flour has considerable nutritional value, with 18% proteins, 3% moisture, 4% ash, 30% lipids, and 35% dietary fibre. Melon flour also has a significantly high content of minerals, mainly phosphorus (1507.62 mg/100 g), potassium (957.35 mg/100 g), and magnesium (504.03 mg/100 g). The polyunsaturated fatty acid fraction was the most abundant in melon seed flour, with predominance of omega-6 fatty acids (17.95 g/mg of sample). Sensorial analysis disclosed good acceptance for formulations containing 10% and 30% of melon seed flour, with the 10% formulation being the most accepted. The research showed the feasibility of using the melon seed flour in cake production, as well as the possibility of using food waste in restaurants and food industries in order to adhere to sustainable production actions.

Phenolic Content and Antioxidant Activity of Extracts of 12 Melon (Cucumis melo) Peel Powders Prepared from Commercial Melons.

Melons are a diverse group of fresh, dessert fruits that includes orange flesh cantaloupe, green flesh honeydew, and mixed hybrid melons. As part of an effort to discover potential health benefits of fruit and vegetable peels that are considered to be byproducts of food processing, we determined the total phenolic content and antioxidative activities of methanolic extracts of the powdered peels of the following commercial melon (Cucumis melo) varieties sold at retail markets in California that were imported from Mexico and Honduras: nonorganic Canary, Charentias, Hani Gold, Vine ripened, and Santa Claus; and organic Ambrosia, Cantaloupe, Galia, Goddess, Ham, Honeydew, and Tuscan. The total phenolic content (in mg gallic acid equivalents/g extract) ranged from 0.69 (Tuscan) to 2.96 (Galia) or 4.3-fold variation from lowest to highest value. The antioxidative activity (in mg ascorbic acid equivalents/mL extract) ranged from 0.13 (organic Tuscan) to 0.26 (organic Galia). Similar results were observed using the ABTS antioxidative assay. The content of the phenolic and flavonoid compounds 3-hydroxybenzoic acid, chlorogenic acid, neochlorogenic acid, isovanillic acid, apigenin-7-α-glucoside, luteolin-7-o-glucoside, and quercetin-3-galactoside in three melon flesh samples (nonorganic and organic Galia from Honduras and organic Galia from Mexico and two peel samples (Mexican organic peel and flesh) were analyzed using HPLC. The results suggest that the peel from the Honduran Galia melon with the highest antioxidative activity merits further study to investigate potential health properties. Potential nutritional and health benefits of melon peels, Seeds, and their bioactive compounds are discussed. PRACTICAL APPLICATION: The peel from the Honduran Galia melon variety merits further study for potential health benefits, including antioxidative, anticholesterol, and antidiabetic activities, and stimulation of thyroid function, as reported for peels from other melon varieties, as well as antibiotic activities against pathogenic bacteria, protozoa, and viruses.

Nanoencapsulation improved water solubility and color stability of carotenoids extracted from Cantaloupe melon (Cucumis melo L.).

Cantaloupe melon carotenoids were encapsulated in porcine gelatin, whey protein isolate and concentrate by emulsification O/W to evaluate which agent could promote an increase in water solubility, and color stability in yogurt. The average particle size obtained was 59.3 (2.60) nm-161.0 (27.30) nm. Encapsulated crude extract in porcine gelatin presented the smallest size and polydispersity index [0.4 (0.04)], and showed sphericity, smooth surface and low agglomeration in SEM. These results associated to the good chemical interaction between the raw materials shown by FTIR, justify the increase in water solubility [0.072 (0.007) mg.mL-1] compared to the crude extract [0.026 (0.003) mg.mL-1]. The yogurt added with this nanoencapsulate remained stable for 60 days, unlike the crude extract. The results show that the nanoencapsulation using gelatin increased water solubility and the potential of application of melon carotenoids in food as natural dyes.

Strobilurin and boscalid in the quality of net melon fruits / Estrobirulinas e boscalida na qualidade de frutos de melão rendilhado

Until recently, fungicides were used exclusively for disease control; however observations of physiological effects brought a new concept to the use of these products. Strobilurins have positive physiological effects on crop yield, due to the increase of liquid photosynthesis and better hormonal balance. However, boscalid complements the action of these fungicides, applied alternately or together. The aim of this study was to evaluate the effect of strobilurins (azoxystrobin and pyraclostrobin), boscalid and the mixture of these on the physical-chemical quality of net melon fruits (Cucumis melo var. Reticulatus). The experiment was conducted in the municipality of São Manuel (SP), using the hybrid of Cantaloupe M2-308 net melon, the experimental design was in randomized blocks with five replicates. The treatments used were: T1 control; T2 azoxystrobin 60g ha-1 of active principle (a.p.); T3 boscalid 75g ha-1 of the a.p.; T4 pyraclostrobin 50g ha-1 of the a.p.; T5 boscalid (37,5g ha-1) of the a.p. + pyraclostrobin (25g ha-1) of the a.p. The first application of the treatments was carried out at fourteen days after the transplanting of the seedlings and the others at seven day intervals, totaling eight applications throughout the cycle. Two fruits of each plot were collected, which were identified for analysis in the laboratory. The following characteristics were evaluated: fresh fruit mass; mesocarp thickness, pulp texture, peel trajectory, pH, titratable acidity, soluble solids and the ratio. The results were submitted to analysis of variance and the averages compared by the Tukey test at 5% probability using the SISVAR program. The fruits of the plants treated with boscalid 75g ha-1 were the ones that showed higher concentration of soluble solids and low titratable acidity, resulting in a better ratio.[...](AU)

Os fungicidas até pouco tempo eram utilizados exclusivamente para o controle de doença, no entanto observações de efeitos fisiológicos trouxeram um novo conceito para o uso desses produtos. As estrobilurinas possuem efeitos fisiológicos positivos no rendimento das culturas, devido ao aumento da fotossíntese líquida e melhor balanço hormonal. Já o boscalida complementa a ação desses fungicidas, aplicado alternadamente ou em conjunto. O trabalho teve como objetivo avaliar o efeito da aplicação de estrobilurinas (azoxistrobina e piraclostrobina), boscalida e a mistura destes na qualidade físico química de frutos de melão rendilhado (Cucumis melo var. reticulatus). O experimento foi conduzido no município de São Manuel (SP), utilizando-se o híbrido de melão rendilhado Cantaloupe M2-308, o delineamento experimental foi em blocos ao acaso com cinco repetições. Os tratamentos utilizados foram: T1 testemunha; T2 azoxistrobina 60g ha-1 do princípio ativo (p.a.); T3 boscalida 75g ha-1 do p.a.; T4 piraclostrobina 50g ha-1 do p.a.; T5 boscalida (37,5g ha-1) do p.a. + piraclostrobina (25g ha-1) do p.a. A primeira aplicação dos tratamentos foi realizada aos 14 dias após o transplante das mudas e as demais a intervalos de sete dias, totalizando oito aplicações ao longo do ciclo. Foram colhidos 2 frutos de cada parcela, os quais foram identificados para as análises no laboratório. Foram avaliadas as seguintes características: massa fresca do fruto; espessura do mesocarpo, textura de polpa, rendilhamento da casca, pH, acidez titulável, sólidos solúveis e o “ratio”. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste Tukey a 5% de probabilidade com auxílio do programa SISVAR. Os frutos provenientes das plantas tratadas com boscalida 75g ha-1 foram os que apresentaram maior concentração de sólidos solúveis e baixa acidez titulável, resultando em melhor “ratio”. [...](AU)

Strobilurin and boscalid in the quality of net melon fruits / Estrobirulinas e boscalida na qualidade de frutos de melão rendilhado

Until recently, fungicides were used exclusively for disease control; however observations of physiological effects brought a new concept to the use of these products. Strobilurins have positive physiological effects on crop yield, due to the increase of liquid photosynthesis and better hormonal balance. However, boscalid complements the action of these fungicides, applied alternately or together. The aim of this study was to evaluate the effect of strobilurins (azoxystrobin and pyraclostrobin), boscalid and the mixture of these on the physical-chemical quality of net melon fruits (Cucumis melo var. Reticulatus). The experiment was conducted in the municipality of São Manuel (SP), using the hybrid of Cantaloupe M2-308 net melon, the experimental design was in randomized blocks with five replicates. The treatments used were: T1 – control; T2 – azoxystrobin 60g ha-1 of active principle (a.p.); T3 – boscalid 75g ha-1 of the a.p.; T4 – pyraclostrobin 50g ha-1 of the a.p.; T5 – boscalid (37,5g ha-1) of the a.p. + pyraclostrobin (25g ha-1) of the a.p. The first application of the treatments was carried out at fourteen days after the transplanting of the seedlings and the others at seven day intervals, totaling eight applications throughout the cycle. Two fruits of each plot were collected, which were identified for analysis in the laboratory. The following characteristics were evaluated: fresh fruit mass; mesocarp thickness, pulp texture, peel trajectory, pH, titratable acidity, soluble solids and the ratio. The results were submitted to analysis of variance and the averages compared by the Tukey test at 5% probability using the SISVAR program. The fruits of the plants treated with boscalid 75g ha-1 were the ones that showed higher concentration of soluble solids and low titratable acidity, resulting in a better ratio.[...]

Os fungicidas até pouco tempo eram utilizados exclusivamente para o controle de doença, no entanto observações de efeitos fisiológicos trouxeram um novo conceito para o uso desses produtos. As estrobilurinas possuem efeitos fisiológicos positivos no rendimento das culturas, devido ao aumento da fotossíntese líquida e melhor balanço hormonal. Já o boscalida complementa a ação desses fungicidas, aplicado alternadamente ou em conjunto. O trabalho teve como objetivo avaliar o efeito da aplicação de estrobilurinas (azoxistrobina e piraclostrobina), boscalida e a mistura destes na qualidade físico química de frutos de melão rendilhado (Cucumis melo var. reticulatus). O experimento foi conduzido no município de São Manuel (SP), utilizando-se o híbrido de melão rendilhado Cantaloupe M2-308, o delineamento experimental foi em blocos ao acaso com cinco repetições. Os tratamentos utilizados foram: T1 – testemunha; T2 – azoxistrobina 60g ha-1 do princípio ativo (p.a.); T3 – boscalida 75g ha-1 do p.a.; T4 – piraclostrobina 50g ha-1 do p.a.; T5 – boscalida (37,5g ha-1) do p.a. + piraclostrobina (25g ha-1) do p.a. A primeira aplicação dos tratamentos foi realizada aos 14 dias após o transplante das mudas e as demais a intervalos de sete dias, totalizando oito aplicações ao longo do ciclo. Foram colhidos 2 frutos de cada parcela, os quais foram identificados para as análises no laboratório. Foram avaliadas as seguintes características: massa fresca do fruto; espessura do mesocarpo, textura de polpa, rendilhamento da casca, pH, acidez titulável, sólidos solúveis e o “ratio”. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste Tukey a 5% de probabilidade com auxílio do programa SISVAR. Os frutos provenientes das plantas tratadas com boscalida 75g ha-1 foram os que apresentaram maior concentração de sólidos solúveis e baixa acidez titulável, resultando em melhor “ratio”. [...]

Effect of antagonistic yeast XL-1 on resistance-associated enzyme activities in postharvest cantaloupe.

The effect of the antagonistic yeast XL-1 on resistance-associated enzyme activities in postharvest cantaloupe was studied by inoculating the antagonistic yeast XL-1. Cantaloupes were sterilized, dried in air, and soaked in antagonistic yeast treatment liquid for 30 s. After drying in air, the cantaloupe was stored at room temperature (2°-5°C). The activities of resistance-associated enzymes in cantaloupe like polyphenol oxidase, ß-1,3-glucanase, peroxidase, and superoxide dismutase were measured every 7 days. Our results indicated that the antagonistic yeast XL-1 significantly improved the activity of ß-1,3-glucanase and chitinase to promote the disease resistance of postharvest cantaloupe.