Descascamento de frutas cítricas pelo uso do tratamento hidrotérmico / Peeling of citric fruits by using Hydrothermal Treatment

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The citrus fruit processing is justified for the difficulty of peeling of these fruits. Studies of peeling of Perasweet orange fruit accomplished at ESALQ-USP are showing the potential of the use of the hydrothermal treatment to facilitate the peeling of this variety. The oranges are immersed in hot water at 50ºC for 8 minutes. This process to make easy the peeling and it doesnt affect the quality of the fruit. However, it is necessary to study other immersion times to make flexible the use of this technique in industrial scale, as well as to extend it for other varieties. The purpose of this work was to adapt the technology of peeling of citric fruits for the use of the hydrothermal treatment, as well as to evaluate the influence of the hydrothermal treatment in the physiological, physicochemical, microbiologic and sensorial qualities of Perasweet orange, Valenciasweet orange and Murcotttangor. The peeling time, the yield of marketable fruits and the internal fruit temperature were also evaluated during the treatment. Fruits were washed, sanitized, cooled at 5ºC for 12 hours, submitted to hydrothermal treatment and peeled. The hydrothermal treatment consisted of putting fruits in water-bath at 50ºC for 5 (only for Murcotttangor), 10, 15, 20, 25 and 30 minutes. Then, fruits were peeled by first opening a gap on the peduncular region with a knife and then, the flavedo was removed, manually, with the albedo. Fruits with no hydrothermal treatment (control) were peeled by first removing the flavedo and then, the albedo was removed carefully to cause the less of injuries possible. The fruits were analyzed for six days of storage at 5ºC. The experiments were carried out separately for each citric fruit and in agreement with each analysis type. The experimental designs used were completely randomized and in randomized blocks, appropriate for each analyzed variable. Hydrothermal treatment caused changes in respiratory activity just in first hours after treatment. Internal fruit temperature (evaluated at 2 cm depth in relation to the epicarp) after 30 minutes of treatment reached 35ºC approximately, temperature commonly observed in some stages of the commercializations chain of the fruits. The external coloration of the oranges without treatment presented larger value of brightness (L) when compared to the treated fruits. There were no changes in the others physicochemicals and microbiologics characteristics of the fruits. The treatment did not change the flavor and it improved the appearance in relation to the fruits without treatment due to the lower albedo residue in the fruits. Besides, the treatment decreased in up to 78% the peeling time of the treated fruits for the Perasweet orange, in up to 75% for the Valenciasweet orange and in up to 57% for the Murcotttangor, when compared to the fruits without treatment, and it increased the yield of marketable fruits. The hydrothermal treatment accomplished up to 30 minutes at 50ºC can be used as peeling technique for Perasweet orange, Valenciasweet orange and Murcotttangor.

ASSUNTO(S)

processamento de alimentos aquecimento descascamento qualidade dos alimentos. murcotttangor valenciasweet orange perasweet orange heat quality. frutas cítricas fresh-cut

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