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UBC Theses and Dissertations

Studies on refrigerated fruit products in flexible pouches Speers, Robert Alexander

Abstract

Selected cultivars of apples, peaches, and cherries were prepared as edible fruit portions, and preserved in flexible pouches under refrigeration. Preserving adjuncts such as sucrose, potassium sorbate, calcium chloride, citric acid and ascorbic acid were added as concentrated solutions to apple slices, peach slices or pitted cherries in Polyester/Polyethylene or Polyester/ Al foil/Polypropylene pouches that were evacuated and nitrogen-flushed prior to sealing. Some of the pouches were placed directly in 4°C storage whereas others were heated in steam or water to provide various blanching treatments prior to refrigerated storage. At various times up to 12 weeks after processing, the fruits were examined for physical, chemical, microbiological and sensory quality. Of the two package structures studied the aluminum foil-containing pouch proved superior to the Polyester/Polyethylene laminate in preserving fruit quality. Results for a series of mild thermal blanch treatments varied with fruit type in terms of microbial stability and sensory quality attributes. For apples, blanching to a center temperature of 80°C proved to be the most satisfactory, whereas 70°C was optimal for peach quality. Cherries, blanched to a center temperature of 80°C, were of good microbial stability. Both. Golden Delicious and Spartan cultivars prepared as apple slices were found to have good flavor, color and textural characteristics after 12 weeks of refrigerated storage. Of the three peach cultivars examined, Fairhaven and Redhaven freestone peaches produced slices of good quality after processing and refrigerated storage of 12 weeks. Fortuna, a clingstone cultivar, had an unsuitable rubbery texture after the storage period. Lambert sweet cherries and Montmorency sour cherries proved to be unsuitable because of problems arising from microbial growth and loss of textural quality. In summary, it was determined that Golden Delicious and Spartan apple cultivars and Fairhaven and Redhaven peach cultivars can be processed into high quality refrigerated fruit products suitable for storage in aluminum foil-containing flexible pouches at 4°C for up to 12 weeks.

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