Influencia da desidratação osmotica com aditivos na estrutura celular e na manutenção da qualidade de goiabas minimamente processadas. / Influence of osmotic dehydration with additives on the cellular structure and quality maintenance of minimally processed guavas.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The main purpose of this work was to study the osmotic dehydration process with additives and evaluating the use of modified atmosphere packaging and refrigeration on guava halves. For osmotic treatment, two sugar types, sucrose and maltose, at different concentrations (40, 50 and 60ºBrix) and two calcium salts, calcium lactate and chloride, at concentrations of 0.5 to 2.5% were used. For shelf life study, guavas were packed in polyethylene terephthalate (PET) containers. The osmotic dehydration assays allowed: 1) to compare the effect of calcium salts on rheological properties, structure by light microscopy and sensory acceptance of osmotically dehydrated guavas; 2) to verify the effect of process variables, sugar type and concentration and addition of different calcium lactate concentrations, on the color and instrumental texture and sensory acceptance of the product; 3) to evaluate the structural characteristics of the osmotically dehydrated fruits with sucrose and maltose solutions with or without the addition of calcium lactate, using light and scanning electron microscopy and calorimetry assays. The shelf life study was carried out with guavas subjected to process conditions selected in the osmotic dehydration assays, and the samples were analyzed with respect to color and rheological properties, weight loss, microbial spoilage and sensory attributes. During the osmotic dehydration trials, it could be verified that the calcium lactate salt was more effective than calcium chloride, providing tissue structural preservation with good sensory acceptance for salt concentrations up to 1,5%. All process variables influenced guavas color and texture characteristics, however, the distinctive effects of these variables were not perceptible by the consumers. The guavas structural evaluation showed the severe tissue damages caused by osmotic process and the preserving effect of calcium lactate on its cellular structure. This preservation due to Ca+2 and guavas pectin linkage was confirmed by differential scanning calorimetry assays. During shelf life study, it was verified that sample packaging under passive modified atmosphere preserved the fruits along the 24 days of storage at 5ºC, resulting in a product with good microbiological conditions, small weight loss and with color and texture characteristics maintenance. However, only the guava osmotically dehydrated with sucrose solution without calcium salt addition showed good sensory acceptance by the consumers during the whole storage period.

ASSUNTO(S)

desidratação osmotica goiaba minimal processing modified atmosphere packaging embalagem sob atmosfera modificada osmotic dehydration processamento minimo guava

ACESSO AO ARTIGO

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