I•IUTTERWORTH I'~IE I N E M A N N 0956-7135(95)00019--4 Food Control, Vol. 6, No. 6, pp. 31%322, 1995 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved I)956--7135/95 $10.(X) + (I.(X) Shelf-life of chilled cut orange determined by sensory quality A.M.C.N. Rocha, C.M. Brochado, R. Kirby and A.M.M.B. Morais* The shelf-life of chilled cut orange was evaluated in terms of physical and chemical quality characteristics, microbial contamination and sensorial acceptability. After minimal processing (peeling and cutting), fresh orange was stored in air at 4°C. Evaluations were performed at different times of storage. The respiration rate of the fresh-cut orange was also evaluated. No significant increase was noticed in relation to the whole fruit which means that this was not the factor responsible for an accelerated deterioration of the product. During the first eight days of storage the major quality parameters remain almost unchangeable, except for titratable acidity which decreased around 36% and ascorbic acid content which decreased around 22%. With respect to microbial contamination low temperature deter- mined a considerable shelf-life (15 days). Sensory quality was the parameter which determined the shelf-life of cut orange to five days at 4°C due to flavour changes. Keywords: minimal processing; peeling; cutting; fresh-cut fruits; orange; chilled; shelf-life; respiration INTRODUCTION The current consumer trend is towards fresh, natural, minimally processed convenient foods (Huxsoll et al., 1989; Rosen and Kader, 1989). Minimally processed fruits are products which have these attributes. Besides the safety aspect, acceptability of those products de- pends mainly upon their organoleptic characteristics: flavour, texture and appearance. Research has pre- viously been carried out to provide the industry with new methods for assuring the quality of these products: Heaton et al. (1969) studied the effects of antioxidants on sensory qualities of fresh sliced peaches; Santerre et al. (1988) tried to optimize the concentration of sul- phide substitutes to preserve the colour of apple slices; Sapers et al. (1990) compared different browning in- hibitors applied to the cut surface of apple; Powrie et al. (1990) suggested the MAP technology as a new method Escola Superior de Biotecnologia, Universidade Cat61ica Portuguesa, Rua Dr. Ant6nio Bernardine de Almeida, 4200 Porto, Portugal. *To whom correspondence should be addressed. to preserve fruit salad; and Stephan (1990) described a method to preserve a tropical fruit salad by using vitamin C, as a browning inhibitor, in the juice. Never- theless, little information is available on the shelf-life of chilled cut orange. Orange provides an important source of ascorbic acid for human nutrition. The juice contains 40-70 mg of ascorbic acid per 100 ml (Reuther et al., 1968). Rushing and Vincent (1962) studied the flavour stability and the microbial population in chilled citrus salads which included orange at different temperatures. They re- ported a loss of typical fresh flavour even at low storage temperature before a significant increase in microbial count was noticed. Baker and Bruemmer (1989) tested a new approach for commercial sectioning of citrus fruits using pectinase peeling and segmenting. In these experiments low temperature was effective in delaying bacterial but not yeast development. Normal losses of flavour quality of the chilled segments could be reduced by the use of controlled atmosphere packaging. The fresh cut fruit is believed to behave differently to the whole fruit. Due to wounding and damage to the skin cut fruits are usually more perishable than fresh Food Control 1995 Volume 6 Number 6 317