Conservação e qualidade pós-colheita em duas variedades de alface submetidas ao hidroresfriamento
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Data
2011-07-16
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Universidade Federal de Viçosa
Resumo
A alface é uma hortaliça folhosa altamente suscetível à perda de água, o que reduz sua vida de prateleira e aumenta o custo final para o consumidor. O objetivo desse trabalho foi avaliar o efeito do hidroresfriamento, como técnica de pré-resfriamento, na conservação pós-colheita de duas cultivares de alface, a ‘Vitoria-de-Santo-Antão’ do tipo solta lisa e a ‘Lucy Brown’ do tipo repolhuda crespa, armazenadas a 5 e 22°C, revestidas com sacos plásticos de polietileno perfurado em caixas de colheita. O hidroresfriamento foi realizado por imersão das cabeças em uma mistura de água com gelo a 4°C (1:3 v/v). Avaliou-se a vida de prateleira, a perda de massa das folhas frescas, teor de clorofila, teor relativo de água, teores de açúcares solúveis totais, açúcares redutores, açúcares não redutores e teor de amido. O hidroresfriamento foi efetivo em retardar o murchamento das folhas a 5 e 22°C, promovendo maior vida de prateleira nas duas cultivares testadas. O hidroresfriamento aliado ao armazenamento à temperatura de 5°C manteve o balanço hídrico das folhas, deixando-as hidratadas durante o armazenamento, promovendo maior período de comercialização do produto. Não houve efeito do hidroresfriamento nos teores de açúcares solúveis totais, redutores, não redutores e amido em nenhuma das temperaturas de armazenamento para as variedades estudadas. Nas ‘Lucy Brown’ a aplicação do hidroresfriamento resultou em um efeito de diluição no teor de clorofila total das folhas no período de análise, porém alterações visíveis na cor não foram detectadas. Na ‘Vitória de Santo Antão’ não houve efeito dos tratamentos e do tempo de armazenamento sob o teor de clorofila total das folhas. O hidroresfriamento a 4°C durante 10 minutos em alfaces do tipo repolhuda crespa, e durante 5 minutos em alfaces do tipo solta lisa, seguido de armazenamento a 5°C é uma técnica eficiente em manter o balanço hídrico das folhas e em promover maior vida de prateleira das alfaces.
Lettuce is a leafy vegetable highly susceptible to water loss, which reduces its shelf life and increases the final cost to the consumer. The aim of this study was to evaluate the effect of hydrocooling as the technique of pre-cooling, on the postharvest conservation of two cultivars of lettuce, ‘Vitória de Santo Antão’ type loose-smooth and the ‘Lucy Brown’ type curly cabbage, stored at 5 and 22° C, coated with polyethylene perforated plastic bags in boxes of harvest. The hydrocooling was performed by immersing the heads in a mixture of ice and water at 4°C (1:3v/v). It was evaluated the shelf life, the weight loss of fresh leaves, chlorophyll content, relative water content, total soluble sugars, reducing sugars, non-reducing sugars and starch. The hydrocooling was effective in slowing down the wilting of the leaves through storage at 5 and 22° C, promoting longer shelf life in both tested cultivars. The hydrocooling combined with storage at 5° C maintained the water balance of the leaves, keeping them hydrated during storage, and providing greater marketing period for the product. There was no effect of hydrocooling in levels of total soluble sugars, reducing, non-reducing and starch in any period of storage and temperatures for the varieties studied. In the ‘Lucy Brown’ the application of hydrocooling resulted in a dilution effect on total chlorophyll content of leaves in the analysis, but no visible changes in color was detected. In the ‘Vitória de Santo Antão’ there was no effect of treatments and storage time on the total chlorophyll content of the leaves. The hydrocooling at 4° C for 10 minutes in the type lettuce curly cabbage and for 5 minutes in the type lettuce loose-smooth, followed by storage of 5° C is an effective technique to maintain the water balance of leaves and to promoter longer shelf life of lettuce.
Lettuce is a leafy vegetable highly susceptible to water loss, which reduces its shelf life and increases the final cost to the consumer. The aim of this study was to evaluate the effect of hydrocooling as the technique of pre-cooling, on the postharvest conservation of two cultivars of lettuce, ‘Vitória de Santo Antão’ type loose-smooth and the ‘Lucy Brown’ type curly cabbage, stored at 5 and 22° C, coated with polyethylene perforated plastic bags in boxes of harvest. The hydrocooling was performed by immersing the heads in a mixture of ice and water at 4°C (1:3v/v). It was evaluated the shelf life, the weight loss of fresh leaves, chlorophyll content, relative water content, total soluble sugars, reducing sugars, non-reducing sugars and starch. The hydrocooling was effective in slowing down the wilting of the leaves through storage at 5 and 22° C, promoting longer shelf life in both tested cultivars. The hydrocooling combined with storage at 5° C maintained the water balance of the leaves, keeping them hydrated during storage, and providing greater marketing period for the product. There was no effect of hydrocooling in levels of total soluble sugars, reducing, non-reducing and starch in any period of storage and temperatures for the varieties studied. In the ‘Lucy Brown’ the application of hydrocooling resulted in a dilution effect on total chlorophyll content of leaves in the analysis, but no visible changes in color was detected. In the ‘Vitória de Santo Antão’ there was no effect of treatments and storage time on the total chlorophyll content of the leaves. The hydrocooling at 4° C for 10 minutes in the type lettuce curly cabbage and for 5 minutes in the type lettuce loose-smooth, followed by storage of 5° C is an effective technique to maintain the water balance of leaves and to promoter longer shelf life of lettuce.
Descrição
Palavras-chave
Hidroresfriamento, Folhosas, Vida de prateleira, Hydrocooling, Leafy, Shelf life
Citação
FRANÇA, Christiane de Fátima Martins. Conservation and postharvest quality of two varieties of lettuce submitted to hydrocooling. 2011. 53 f. Dissertação (Mestrado em Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de) - Universidade Federal de Viçosa, Viçosa, 2011.