30B-11

Approaches to the utilization of lye peel tomato processing by-products

J. MONTECALVO, R. Elizondo, J. H. Dupuy, and O. R. Noyes. Department of Food Science and Nutrition, California Polytechnic State University, San Luis Obispo, CA 93407

Presently the tomato processing industry in the state of California processes in excess of ten million tons of tomatoes each year. Central to the issue of tomato processing are unit operations that use 12-15 percent sodium hydroxide at 215-218°F to facilitate rapid removal of tomato skins prior to further processing. The alkali by-product stream consisting of sodium hydroxide, tomato skins and fragments of tomato historically have been dumped into municipal sewer systems after neutralization creating high sewage fee costs to the processor. This paper will focus on the utilization of this tomato by-product stream by acidification with hydrochloric acid and further processing.

As a function of industry agreements all samples obtained were selected during actual production runs. Titratable acidity, pH, total solids, salt analysis, BRIX and Bostwick consistometry were conducted on all experimental samples. Controls were non-alkali treated tomato and for sensory analysis, a commercial tomato sauce was selected.

Results for tomato sauce produced from acidified tomato peel (ATP) indicated pH values from 3.8 to 4.6, BRIX 3.1 to 4.5, titratable acidity 0.16 to 0.35%, salt levels 0.56 to 0.85%, and total solids of 3.12 to 5.10%. Results from a four sample consumer acceptance test using sequential monadic design showed no significant difference (a=0.05) in odor or texture among 10, 20 and 30% ATP in tomato sauce (N=96). The thirty percent ATP samples were significantly more acceptable (mean 7.37 ± 1.65) for color than the control. Overall the thirty-percent sample and control were found to be more acceptable.

The results of this study suggest that utilization of acidified tomato peel by-product in the form of a thirty-percent blend with tomato sauce may offer a significant approach in the utilization of alkali tomato by-products that could significantly reduce solid by-product and enhance overall production yields.

Session 30B, Fruit & Vegetable Products: Sensory, Product Development, Fresh-Cut, and Storage
1:00 PM - 4:30 PM, 2001-06-24 Room Hall D

2001 IFT Annual Meeting - New Orleans, Louisiana