Evaluation of respiratory parameters in minimally processed lettuce grown under organic or conventional system

Abstract

RESUMOAvaliação de parâmetros respiratórios em alface minimamente preocessada produzida em sistema orgânico ou convencional O aumento da preferência por hortaliças minimamente processada tem sido atribuído aos benefícios à saúde associado aos produtos frescos, bem como à demanda pelo consumo de salada pronta para o consumo. Neste trabalho, a alface americana (Lactuca sativa L.) foi avaliada quanto aos efeitos de diferentes sistemas de cultivo sobre as propriedades respiratórias. A alface foi acondicionada em sacos de polietileno de baixa densidade, conservada em refrigerador a 4 o C. A concentração de dióxido de carbono e de oxigênio no interior das embalagens foi monitorada ao longo da conservação nos tempos 0, 3, 6, 8, 10 e 12 dias por cromatografia gasosa e a variação da matéria seca foi avaliada por gravimetria até o décimo quarto dia de conservação. O valor do padrão respiratório na alface convencional aumentou do primeiro ao terceiro dia e se manteve baixo, enquanto a orgânica aumentou a taxa respiratória até três vezes até o oitavo dia, estabilizando em alto nível. O sistema de cultivo também resultou em diferenças na variação da matéria seca durante o armazenamento. O mais elevado conteúdo de matéria seca foi atingido pela alface americana orgânica.Palavras-chave: Pós-colheita, conservação, vida de prateleira. The increased preference for minimally processed vegetables has been attributed to the health benefits associated with fresh produce and the demand for ready-to-eat salads. In this paper, lettuce (Lactuca sativa L.) was evaluated for the effects of different cropping systems on the respiratory properties. Lettuce was packaged in low density polyethylene bags and stored in a refrigerator at 4 o C. The concentration of carbon dioxide and oxygen inside the package was monitored during the storage at zero, three, six, eight, ten and twelve days by gas chromatography. Dry matter variation was measured gravimetrically up to day fourteen of storage. Values of respiratory rate for conventional lettuce increased from day 1 to 3 and remained low, while respiratory rate of the organic lettuce increased three-fold up to day 8, stabilizing at a high level. Variation in dry matter during storage also resulted from differences between the two cultivation systems. The highest content of dry matter was achieved by organic lettuce.

Effect of nitrogen fertilisation on the overall quality of minimally processed globe artichoke heads

“…To our knowledge, no study has addressed the change in respiratory performance of artichoke as a function of nitrogen fertilisation level. Only one study addressing the influence of the cultivation system on the respiratory parameters of lettuce found that conventional cultivation determined a lower RQ compared to organic cultivation, whose RQ was close to unity: this difference is likely to be determined by the higher nitrogen supply of the first treatment, thus results are in agreement with the present findings.…”

Consumer Preference, Quality, and Safety of Organic and Conventional Fresh Fruits, Vegetables, and Cereals

“…Organic fruits and vegetables performed better in visual quality and shelf life compared with the conventionally grown ones. For example, organic lettuce exhibited a longer shelf life than the conventionally grown ones [ 42 ].…”

“…Dry matter content increases the flesh product of organic lettuce and, as a result, produce shows less decay and decomposition with increased storage life [ 42 ]. Yu et al [ 33 ] reported that dry matter content accumulated by photosynthesis is almost 7–20% higher in organic crops than in the conventionally grown ones.…”