Respiration rates of whole and minimally processed apples under modified atmospheres

Author

Manuel A. Ortega

Date of Award

8-1993

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

Rabindra N. Biswal

Committee Members

John Mount, Carl E. Sams

Abstract

An automated system was developed for measuring respiration rates of whole and minimally processed fruits and vegetables. The system consisted of the following components: an electrochemical O₂ analyzer, two plexiglass chambers, four solenoid valves, an electronic timer, and a data acquisition system. The system was used for measuring respiration rates of whole apples, fresh apple rings and apple rings osmotically concentrated in 60% sucrose—water solution (w/w) at 24 °C for 3 hours. Respiration behavior of whole and minimally processed Red Winesap apples was measured. Two temperatures (10 and 24 °C) and two starting atmospheres (atmospheric air (21% O₂) and 5% O₂ + 95% N₂) were evaluated in the study. Oxygen consumption, CO₂ generation and C₂H₄ production rates were determined.

Slicing of apples to obtain fresh apple rings increased the respiration rate to almost double that of whole apples. The respiration rate of apple rings was, however, reduced when they were osmotically concentrated in 60% sucrose—water solution (w/w) at 24 °C for 3 hours. Respiration rates of whole apples, and fresh and osmotically concentrated apple rings under atmospheric air as the starting atmosphere at 10 °C was found to be lower than the respective respiration rates at 24 °C.

Respiration rates of whole apples, and fresh and osmotically concentrated apple rings under the modified starting atmosphere (5% O₂ + 95% N₂) at both temperatures (24 and 10 °C) varied with time. In general, the respiration rates for osmotically concentrated apple rings were found to be lower than those for fresh apple rings, and slightly higher than those for whole apples. The only exception was that the CO₂ production of osmotically concentrated apple rings at 10 °C was higher than that for whole apples and fresh apple rings. This could be due to fermentation of sucrose.

Ethylene production in osmotically concentrated apple rings under both atmospheres (atmospheric air and 5% O₂ + 95% N₂) nd at both temperatures was found to be lower than that in whole apples and fresh apple rings. This suggests that osmotic concentration suppressed the rates of ethylene production in apples.

Results of this study are useful in the design and development of modified atmosphere packages for whole and minimally processed apples. This study could be extended for other fruits and vegetables.

Recommended Citation

Ortega, Manuel A., "Respiration rates of whole and minimally processed apples under modified atmospheres. " Master's Thesis, University of Tennessee, 1993.
https://trace.tennessee.edu/utk_gradthes/6918