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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Extending shelf-life of fresh-cut pears

Dong, Xiaoling 25 September 1998 (has links)
Different concentrations of various browning inhibitors and a firming agent were evaluated to prevent browning and softening of Bartlett, Bosc and Anjou pear slices during cold storage at 2-4°C. Browning inhibition effect of Semperfresh, Snow Fresh and cysteine were compared with that of 4-hexylresorcinol (4-HR). The effect of ripeness on color and texture changes as well as the influence of storage temperature on texture and color retention was investigated. 4-HR residual content under different treatment conditions and its sensory properties were analyzed. 4-HR was an effective browning inhibitor at concentration as low as 0.005% when combined with 0.5% ascorbic acid (AA). Cysteine (0.5%) with 0.5% ascorbic acid (AA) effectively inhibited Anjou and Bosc pear slice browning for 25 days and its sensory properties merit further study. A combination of 1.0% AA and 1.0% calcium lactate prevented Anjou pear slices from discoloration, but also caused tissue leaking and softening. Semperfresh and Snow Fresh did not maintain flesh color effectively. 1.0% calcium lactate maintained slice firmness at an acceptable level for 30 days when the average firmness of whole pears at slicing was 49, 38 and 43 Newton (N) for Bartlett, Bosc and Anjou respectively. A storage temperature of 0°C significantly retained better texture than the control of 2-4°C. Slices with acceptable texture and color were achieved by treatment with a solution of 0.01% 4-HR, 0.5% AA, and 1.0% calcium lactate for 2 min, vacuum packaging, and storage at 2-4°C for 30 days for Bartlett and Bosc, and 15 days for Anjou. 4-HR residual content increased with increasing dipping times and concentrations, with the latter being the major factor. The 4-HR residual decreased with storage time for all the treatments. Sensory tests indicated that panelists detected the overall differences between 0.01% 4-HR treated samples and the controls for both Bartlett and Anjou pears (P<0.01). There were no significant differences in preference between treated sample and control for Anjou pears. / Graduation date: 1999

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