Masters Theses

Dharia Renate

Date of Award

8-1991

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

J. L. Collins

Committee Members

David L. Coffey, Rabindra N. Biswal, John R. Mount

Abstract

The objectives of this research were to determine the concentrating effect of different concentrations of sucrose or salt on tomato flesh and to measure/evaluate chemical, physical and sensory quality properties after dehydration.

Fresh tomatoes of Roma and Milano cultivars were prepared and concentrated partially in solutions of sucrose (50, 60, 70%) or salt (10, 15, 20%). Times for holding in solution were extended up to 2 hr in sucrose solution and 1.5 hr in salt solution. Moisture loss, solids weight gain and net weight loss were measured at designated times during these periods. Following these determinations, the tomato flesh was dehydrated at 57°C for 14 hr. Color was measured on the dehydrated tomato.

Tomato samples were prepared for sensory evaluation, using sucrose solution (60%, 1.5 hr) and salt solution (15%, 1 hr). The dehydrated tomato was stored 2 and 4 months in sealed glass containers after flushing with nitrogen gas.

The longer the time of holding tomato flesh in either solution and the greater the concentration of solute, resulted in the greater the loss of moisture, gain in solids content and loss of net weight. Cultivar exhibited limited effect on these measurements.

Hunter color values of dehydrated tomato from the sucrose treatment were greater after 1 hr but no changes occurred with longer times. Sucrose concentration and cultivar had no effect on color. For salt-treated tomato, Hunter values increased with time of treatment, but the greatest increase occurred for L and 'b' values. Salt concentration and cultivar exhibited minor color changes.

Panel scores for sucrose-treated tomato of both cultivars ranged between means 5.7 and 6.6 ("like slightly" and "like very much"). Scores for salt-treated tomato in pasta sauce were highest at 6.0 ("like moderately") for color; for fresh tomato in pasta sauce, scores were highest at 5.2 and 5.0 ("like slightly") for flavor and overall acceptability, respectively. Female panelists give the higher scores for flavor and overall acceptability. Storage time had no effect on sensory scores.

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