Alterações químicas, físicas e físico-químicas da tangerina 'ponkan' (Citrus reticulata Blanco) durante o armazenamento refrigerado

Abstract

This work was aimed to evaluating chemical, physical and physical–chemical changes on tangerine 'Ponkan' (citrus reticulata Blanco) during the storage at 5 ± 2° C under relative humidity of 85 ± 3%, for a period of 28 days, in two maturation stadiums (fruits collected at the beginning of the crop; with the greenest peel and yellow peel fruits,, collected by the end of the crop). Fruits with stalf were alleatory collected in a seven–years old commercial orchard, located at Perdões, South area of the State of Minas Gerais. Fruits were collectd twice: on April, when they got a green peel, but they were already edible; and on July, by the end of the crop, when fruits got a very yellow peel. Then fruits were taken to the Laboratory of Biochemistry of the Federal University of Lavras, where a hundred aff them with uniform size and injury were washed with a 1% sodium hypochoride solution, marked, weigthted measured and submitted to color readings. After 0, 7, 14, 21 and 28 days in a refrigerator at fruits of uniform size and with absence of offenses to each crop, these were washed with a hipoclorito of sodium solution to 1%, recorded, heavy, measured and accomplished the color readings. Then the fruits were stored then in refrigerator at 5 ± 2° C, under relative humidity of 85 ± 3%, fruits as well as thein juice were analysed. The experimental outline used was entirely randomized, with five replicates containig four fruits in each one. Almost all rescelts were significantly dependent on the number of storage days. Loss and traverse and longitudinal diameter presented significant decreases as the number the of refrigerated storage days increased. Sugar concentration also had significant variations, increasing with storage. pH and vitamin C did not present significant variations. Fruit pell coloration was measured in a color imeter using there colour variables: brightness, yellow and red intensity. Cold be observed visuallty that fruits collected in the beginning of the crop, specially those with granulation, aftem one week of storage, presented juice vesicles dried, while fruits collected riper, with larger amounts of soluble sugars, were more resistant inernal drying of vesicles (visual and tactile analysis).