Quality Comparisons of Tomatoes Irradiated with Light, Treated with Ethylene, and Stored in Darkness

  • Lee, Gwi Hyun (Division of Agricultural Engineering, Kangwon National University) ;
  • Bunn, Joe M. (Department of Agricultural and Biological Engineering, Clemson University) ;
  • Han, Young J. (Department of Agricultural and Biological Engineering, Clemson University)
  • Published : 2000.12.01

Abstract

Quality characteristics of tomatoes irradiated with light (red light of far-red light followed two days later with a red light treatment), treated with ethylene, and stored in darkness were evaluated by subjective sensory and objective physical and chemical evaluations. Overall and individual liking evaluations and sensory evaluations were made by an untrained panel of eighteen people. A rankin gof treatments for consumer (panelist) acceptability was also conducted by the panel. Physical and chemical evaluations included surface color measurement (L*, a*, and b*), mechanical puncturing (firmness), soluble solids content (SSC), titratable acidity(TA), and tomato juice pH. Sensory data showed that outside color, inside color, and flavor of tomatoes treated with red light (R) and far-red light/red light (FR/R) were scored significantly higher than those of tomatoes treated with ethylene and those kept in darkness. The L* values for tomatoes treated with R and FR/R were lower (more darkening) than those for tomatoes treated with ethylene and those stored in darkness. Tomatoes treated with FR/R had the highest A* values, followed by those irradiated with R, treated with ethylene, and kept in darkness, respectively. Sensory values for firmness were similar for tomatoes treated with R, FR/R, and ethylene. Treatments had no significantly different effects on sweetness and acidity. There were no significantly different effects between treatments for pH, SSC, TA, and SSC/TA. From observations made during the study, it was suggested that R irradiation stimulated red color development in tomatoes after it had been delayed by FR irradiation. Consumer acceptability for tomatoes with either R or FR/R treatment was significantly higher than that for tomatoes treated with ethylene or stored in darkness. panelists' overall liking scores correlated well with all sensory variables except acidity, and also correlated highly with inside color, flavor, and sweetness (P<0.001). Overall liking versus flavor had the most pronounced relationship (r=0.78, P<0.001).