Submitted to: Journal of Food Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/4/2004
Publication Date: 3/1/2005
Citation: Fan, X., Niemira, B.A., Mattheis, J.P., Hong, Z., Olson, D.W. 2005. Quality of fresh-cut apple slices as affected by ionizing radiation and calcium ascorbate treatment. Journal of Food Science. 70(2) S143-148. Interpretive Summary: The major concerns with many fresh-cut fruits (fruit salad) are microbial safety and surface browning. Ionizing radiation effectively inactivates bacteria that cause illness and spoilage in food while antibrowning agents are applied to reduce tissue browning. This study investigated the effects of a antibrowning agent (calcium ascorbate) and irradiation on acidity, firmness, color, vitamin C content and bacteria population of apple slices in modified atmosphere packaging. Fruit slices prepared from Gala apples were dipped into calcium ascorbate solution followed by exposure to low dose gamma radiation. The results demonstrate that a combination of calcium ascorbate and irradiation results in microbiologically safe and high quality fresh-cut apples rich in nutrients (calcium and vitamin C). The information will be useful for the fresh-cut fruit industry to improve food safety and quality of cut apples.
Technical Abstract: Although ionizing radiation effectively inactivates foodborne bacterial pathogens in fresh-cut fruits and vegetables, it may adversely affect product quality. In this study, the effect of calcium ascorbate (CaA) and ionizing radiation on quality of 'Gala' apple slices under modified atmosphere packaging was investigated. 'Gala' apple slices, treated with water or 7% CaA followed by either nonirradiation (0 kGy), or irradiated at 0.5 and 1.0 kGy, were stored at 10 C for 3 weeks. Irradiation did not affect titratable acidity and pH of sliced apples, however, fruit slices softened following irradiation and during storage. The decrease in firmness during storage was reduced by the CaA treatment. Although the ascorbic acid content of apple slices treated with CaA decreased rapidly during storage, the ascorbic acid content was always higher in those treated samples than in the apple slices treated with water. Irradiation decreased both L* and hue values of apple slices. Hue values decreased during the entire storage period while L* increased during the first week of storage, then decreased between 1-3 weeks of storage. CaA increased L* and hue values of apple slices, suggesting CaA reduced browning even in irradiated samples. The microflora population of apples slices was not affected by CaA, and CaA treatment did not alter the reduction in microflora by irradiation. The combination of CaA and irradiation enhanced microbial food safety while maintaining quality of fresh-cut apple slices.