Anatomic and physiological characterization and conservation of minimally processed carrots / Caracterização anatômico-fisiológica e conservação de cenoura minimamente processada

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The objective of this study was to characterize the dehydration, white blush and histological location of suberin, lignin and phenolic compounds and assess their contribution to superficial white blush in baby carrots. The effects were assessed of the controlled atmospheres consisting of 2 % O2 + 15 % CO2, 5 % O2 + 5 % CO2 and 10 % O2 + 10 % CO2, all with N2 and environment balance; and modified atmospheres associated to the use of antimicrobial edible covering, in chilled baby carrot storage. White blush was observed in the first hours of minimal processing for baby carrots that were not packed and in the first days when packed in polyvinyl chloride film at 5 C and 90 5 % relative humidity. This fact occurred simultaneously with dehydration and minimal water losses were observed in the baby carrots that were sufficient to damage their appearance, because of the white blush. Although the mini carrot surface was rehydrated, depending on the intensity of the dehydration, the symptoms could not be reverted, suggesting that reversion of white blush is not undefined. It was observed that phenilalanine ammonia-lyase (PAL) activity in the surface tissue of the baby carrot secondary phloem was not related to lignin accumulation but to precursor phenolic compounds. Therefore, lignin is not associated to white blush on the baby carrot surface. When baby carrots were stored in environment atmosphere, their total quality was altered by the flavor, due to perception of bitterness, and by their appearance, based on the evolution of white blush on the surface. It was observed that baby carrots submitted to atmospheres of 2 % O2 + 15 % CO2 and 5 % O2 + 5 % CO2, N2 balance, had few alterations in flavor, ascorbic acid contents, dehydroascorbic acid, total carotenoids and phenolic compounds. The 5 % O2 + 5 % CO2 atmosphere, because it permitted less probability of anaerobic respiration, was a suitable atmosphere for baby carrot storage, for 12 days, compared to the 2 % O2 + 15 % CO2, atmosphere, if the temperature altered during the distribution logistics or even on the supermarket shelves. In all the cases, atmosphere control was not sufficient to maintain the total baby carrot quality and white blush showed on the surface. On the other hand, this symptom was minimized with the use of edible covering. Carrots cut in sticks, with edible covering containing starch and chitosan, in association with the atmosphere modified by two films (A and B) with different permeability to O2 and CO2, maintained the original orange color of the surface, did not present strange flavor and maintained acceptable microbiological quality. The respiratory metabolism was altered, along with vitamin C, total carotenoids the phenolic compounds and their individual components. Under the conditions studied, stick carrots that were covered with edible film and packed with film A with greater O2 permeability, kept acceptable sensorial and microbiological qualities for a longer period.

ASSUNTO(S)

phytochemistry botanica esbranquecimento carrot qualidade quality composition cenoura fitoquímica phenolic metabolism composição white blush metabolismo fenólico

ACESSO AO ARTIGO

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