Potassium permanganate (KMnO4) is a powerful ethylene (C2H4)-scavenging agent widely used in fresh horticultural commodities to delay the postharvest maturation. According to databases, it has been used for almost 50 years in food-packaging systems, and over 70 studies have evaluated its effects on fresh produce quality, mainly on climacteric fruit. However, the use of KMnO4-based technology remains limited at a commercial scale, since there are still lots of doubts on its potential as an effective postharvest tool, as well as in relation with health, environmental and safety concerns. Depending on the commodity, and even the variety, these scavengers may have different effects, but overall, they can delay ripening/senescence-related processes such as chlorophyll degradation/colour changes, weight and firmness losses, disorders and diseases, acidity and sugar changes. This review comprises an updated overview of the current knowledge regarding the use of KMnO4 as C2H4-scavenging agent, providing a concise appraisal on KMnO4-based C2H4 removal application and its effect on the quality of fresh produce. KMnO4 is commonly supported onto microporous mineral particles, which are placed into small sachets to avoid direct food contact within packages. Generally, KMnO4-based C2H4 scavengers are jointly used with modified atmosphere packaging. Hence, KMnO4-based C2H4-scavenging systems, as an active food-packaging technology, seem to be a relevant option to preserve the quality and safety of fresh horticultural produce. Nevertheless, although there are many KMnO4-based products available in the market, which are presently reviewed, more research is required in order to obtain an optimal C2H4-scavenger performance.

Potassium permanganate-based ethylene scavengers for fresh horticultural produce as an active packaging.

Preharvest aminoethoxyvinylglycine (AVG) and 1-methylcyclopropene (1-MCP) effects on ethylene and starch concentrations of ‘Empire’ and ‘McIntosh’ apples

Combined effects of aminoethoxyvinylglycine and MAP on the fruit quality of kiwifruit during cold storage and shelf life

Fuji' apple trees grown on Inceptisol and Entisol were annually fertilized with doses of N and K2O (0, 50, 100, and 200 kg ha-1, for both) along nine growing seasons. Changes of fruit maturity and quality at harvest and after cold storage in response to N and K2O fertilization were not the same for the two soil types. The increment of N rate applied increased the N content and reduced the starch content and peel red color of the fruit in both soils, regardless of K2O rate. On the Entisol, the increment of N rate increased the fresh mass and reduced the flesh firmness of the fruit, regardless of K2O rate, while in the Inceptisol this response was not consistent. Fruit titratable acidity (TA) reduced with the increment of N rate in both soils, especially at low rates of K2O. For the orchard on Inceptisol, the K and starch contents, TA, fresh mass, and peel red color increased, while the flesh firmness reduced consistently and independently of N rate, with the increment of K2O rate, but not for the orchard on the Entisol. The effects of N and K2O rates on flesh firmness and TA of the fruit were more evident after cold storage than at harvest.

https://www.scielo.br/pdf/rbf/v35n1/35.pdf

Qualidade de maçãs 'Fuji' influenciada pela adubação nitrogenada e potássica em dois tipos de solo

Thinning promotes an increase in fruit size, balance between vegetative growth and productive and prevents switching of production. The aim of this study was to evaluate the effect of different concentrations of ethephon on chemical thinning of plum cv. Irati, at 4 years old on rootstock A-9 spaced 5.0 x 2.5 m, in the municipality of Arapoti - PR. Five treatments were tested at ethephon concentrations of 0.1; 0.125; 0.15; 0.2 mg L-1, applied 30 days after full bloom. The following characteristics were evaluated: average number of fruits per branch, number of fruits form whole plant at harvest point, yield per plant, fruit weight, fruit diameter, soluble solids, fruit stiffness, acidity, pH and color. Increased in the concentration of ethephon linearly reduced the number of fruit, I, II and III diameter, increasing the number of fruit of IV diameter, larger fruit, obtained with the concentration of 0.093 mg L-1 of ethephon. The drought in August and September may have affected the smooth fruit development.

/pdf/aplicacao-de-ethephon-no-raleio-quimico-de-ameixeira-e-seu-3i4m1uvfkk.pdf

Aplicação de ethephon no raleio químico de ameixeira e seu efeito sobre a produtividade

The objective of this research was to evaluate the effects of ethylene action inhibition (by sprayable formulation of 1-methylcyclopropene; 1-MCP) and ethylene synthesis inhibition (by aminoethoxyvinylglycine; AVG) on preharvest apple fruit maturation. ‘Royal Gala’ apple trees were sprayed with 1-MCP (at 50 or 100 mg L-1)) seven days before anticipated harvest (DBAH), or with AVG (124 mg L-1)) 28 DBAH. Apple trees not sprayed with 1-MCP and AVG were used as control. Fruit were harvested weekly,along five weeks from the 7th day after 1-MCP spraying, and then analyzed in terms of maturity and quality one day after harvest. Fruit maturity and quality attributes when fruit reached the flesh firmness of 71.1 N were estimated by analysis of regression, for each treatment. 1-MCP (50 and 100 mg L-1)) and AVG delayed fruit maturation, by reducing the ethylene production rates, starch degradation, loss of flesh firmness and acidity, skin yellowing, increase of soluble solids content and skin red color development. 1-MCP (100 mg L-1)) and AVG delayed in 6 and 12 days, respectively, the time required for fruit to reach the flesh firmness of 71.1 N on the tree, in comparison to the control. Fruit treated with 1-MCP or AVG had starch index, ethylene production and acidity values similar or smaller than the control, at the date when all treatments achieved the flesh firmness of 71.1 N. The magnitude of 1-MCP effect on flesh firmness was similar to the effect on ethylene production and skin color, and slightly slower on starch degradation. The effects of AVG on ethylene production, skin color and acidity were more substantial than on loss of flesh firmness. The results show that the treatment of ‘Royal Gala’ apple trees with the sprayable formulation of 1-MCP represents an additional method for management of fruit maturation and harvest.

/pdf/controle-da-maturacao-pre-colheita-de-macas-royal-gala-pela-56sbm7saae.pdf

Controle da maturação pré-colheita de maçãs ‘royal gala’ pela inibição da ação ou síntese do etileno

The study evaluated the efficacy of a sprayable formulation of 1-methylcyclopropene (1-MCP) to delay fruit maturation on the tree in comparison to aminoethoxyvinylglycine (AVG). 1-MCP (150 mg L-1) and AVG (124 mg L-1) were sprayed to 'Imperial Gala' and 'Royal Gala' apple trees from two commercial orchards, 7 and 28 days before commercial fruit harvest maturity, respectively, during four consecutive years. Untreated trees were used as control. Fruit were harvested weekly, during four weeks from the 7th day after 1-MCP spray and assessed one day after harvest. The extent of fruit maturation delay on the tree by 1-MCP and AVG was quantified by linear regression analysis of fruit firmness as a function of harvest date. The estimated date when apple fruit reached firmness of 71.1 N on the tree was delayed for 5.3 to 5.6 days by 1-MCP and for 9.0 to 9.4 days by AVG in comparison to the control, depending on cultivar-orchard. Indices of fruit maturity and quality at harvest were also estimated by linear regression analysis for the estimated date when fruit reach flesh firmness of 71.1 N on the tree. 1-MCP and/or AVG treated fruit had similar or lower ethylene production rates, starch index, titratable acidity and red color and similar or greener background color than control, at estimated harvest dates when fruit of all three treatments reached the same firmness of 71.1 N. 1-MCP and AVG treatments did not affect rates of fruit growth. However, at estimated dates when fruit of all treatments reached the firmness of 71.1, 1-MCP and AVG treated fruit were 2.1 to 7.1% larger than control fruit.

Preharvest treatment of 'Gala' apples with 1-MCP and AVG – I: effects on fruit maturation on the tree

Preharvest treatment of ‘Gala’ apples with 1-MCP and AVG – II: effects on fruit quality after storage

This research was carried out to assess the effects of fruit maturity at harvest and its treatment with 1-methylcyclopropene (1-MCP) on flesh browning (chilling injury) and ripening during cold storage of 'Laetitia' plums. Fruits were harvested at two maturity stages in commercial orchards located in Lages (in 2006 and 2008) and Sao Joaquim (in 2008): with 20-45% (maturity 1) and 46-80% (maturity 2) of surface with red coloration. Fruit were cold stored in air, at 0.5oC ± 0.5oC and 90-95% RH, within 36 h after harvest, treated four days latter with zero (control) or 0.5 µL.L-1 of 1-MCP, and then kept under refrigeration for up to 73 days. Fruit were assessed at harvest, periodically during cold storage and after three days of shelf life (at 22±4oC) in terms of flesh firmness, titratable acidity (TA), soluble solids content (SSC) and incidence of shrinkage, flesh browning and decay. In Lages, fruit harvested at the maturity stage 1 had flesh firmness values of 2.5 to 2.3 lb higher than fruit harvested at the maturity stage 2, in 2006 and 2008, respectively. In Sao Joaquim, fruit harvested at the maturity stage 1 had flesh firmness value 1.3 lb higher than fruit harvested at the maturity stage 2. The fruit harvested at an advanced maturity (maturity 2) and the treatment with 1-MCP delayed the expression of flesh browning during cold storage, regardless of orchard location and year. In general, for fruit harvested at maturity stage 2 and treated with 1-MCP, the increase of cold storage period without the occurrence of flesh browning, assessed after three days of shelf life, was >20 days, in comparison to fruit harvested at maturity stage 1 and non-treated with 1-MCP. Additionally, 1-MCP delayed the loss of flesh firmness, but it did not substantially improve the preservation of TA and SSC of the fruit during cold storage.

/pdf/controle-do-escurecimento-interno-de-ameixas-durante-o-34kg16srs0.pdf

Controle do escurecimento interno de ameixas durante o armazenamento pelo manejo do ponto de colheita e do etileno

O presente estudo analisou os efeitos do inibidor da acao do etileno 1-MCP (1-metilciclopropeno), da AM (atmosfera modificada) e do oxidante de etileno KMnO4 (permanganato de potassio) sobre a qualidade de caqui 'Fuyu' apos a armazenagem refrigerada. Os fatores 1-MCP, AM e KMnO4 foram combinados de quatro maneiras, correspondendo aos seguintes tratamentos: T1) Controle + AM + KMnO4;T2) 1-MCP + AM + KMnO4; T3) 1-MCP + AM, e T4) 1-MCP + AA (AA=atmosfera do ar). Frutos maduro-firmes com coloracao da casca predominantemente amarela foram colhidos em sete pomares comerciais no nordeste do Estado do Rio Grande do Sul. Parte dos frutos foi exposta a 0.3 µL L-1 de 1-MCP por 12 h em 24 h apos a colheita. A seguir, os frutos foram armazenados sob AA ou sob AM induzida por bolsas de polietileno (0,04 mm de espessura), por 20; 40; 60 ou 80 dias a -0,1±0,8oC. Dois saches contendo 8,5 g de Alumina-KMnO4foram adicionados em cada uma das bolsas de polietileno dos tratamentos um e dois, antes de elas serem vedadas. Os frutos de cada periodo de armazenagem refrigerada foram analisados apos 0; 3; 6 ou 9 dias de prateleira sob AA a 22±1oC. O tratamento 1-MCP retardou o amolecimento da polpa, mas nao afetou consistentemente o desenvolvimento de 'estrias' e manchas pretas na superficie dos frutos armazenados sob AM contendo KMnO4. A incidencia de 'estrias' e manchas pretas em frutos tratados com 1-MCP e armazenados sob AM foi significativamente menor que a de frutos tratados com 1-MCP e armazenados sob AA. Houve efeitos aditivos do 1-MCP e AM na conservacao da firmeza e na reducao de danos por frio manifestados pela formacao de textura gel-firme e manchas translucidas na casca. O uso de KMnO4 nao aumentou a conservacao da qualidade dos frutos quando tratados com 1-MCP e armazenados sob AM. O desenvolvimento dos disturbios da epiderme dependeu do pomar e de periodos de armazenagem e prateleira. No entanto, os beneficios da combinacao de 1-MCP e AM sobre a reducao desses disturbios e do amolecimento dos frutos foram consistentes para todos os pomares. Os resultados indicam que a combinacao de 1-MCP e AM e um metodo efetivo para retardar a deterioracao de caqui 'Fuyu' durante e apos a armazenagem refrigerada.

/pdf/conservacao-da-qualidade-de-caqui-fuyu-em-ambiente-b6th0q8rn5.pdf

Andreia Maria Tomazini Scolaro

Papers

Controle da maturação pré-colheita de maçãs ‘royal gala’ pela inibição da ação ou síntese do etileno

Preharvest treatment of 'Gala' apples with 1-MCP and AVG – I: effects on fruit maturation on the tree

Preharvest treatment of ‘Gala’ apples with 1-MCP and AVG – II: effects on fruit quality after storage

Controle do escurecimento interno de ameixas durante o armazenamento pelo manejo do ponto de colheita e do etileno

Conservação da qualidade de caqui 'Fuyu' em ambiente refrigerado pela combinação de 1-MCP e atmosfera modificada