A 2-year project was undertaken to determine the commercial feasibility of recovering pulp from the peelings of caustic peeled tomatoes. In 1975, peel from regular cannery operations was processed through a 20-gpm (5 t/hr) continuous-flow line. This processing consisted of acidifying the peel to pH 4.2 with food-grade hydrochloric acid, then separating the pulp from the skin with a paddle finisher (screen). Recovered peel pulp was found to be of food quality but contained high peeling-aid residues (150-450 ppm). In 1976, a 1-t/hr pilot peeling line was set up at a cannery to study modifications in the peeling process for the purpose of reducing peeling-aid residue in the recovered pulp. The principal modification was to pretreat the tomatoes by immersion in a 150F aqueous bath (approximately pH 3.6) containing about 0.15% food-grade octanoic (caprylic) acid; subsequently, the tomatoes were immersed in caustic. The peel was removed with rubber-disc peelers. Recovered pulp met USDA Quality Grade A, and the octanoic acid levels were low (0 to 30 ppm). The proposed use of this recovered peel pulp is in combination with tomato pulp from regular sources for canned products such as tomato sauce, catsup, paste, and fill juice for peeled tomatoes.

Interagency agreement EPA-IAG-D5-0795. "EPA 600-2-78-202." "September 1978." Cover title. Includes bibliographical references (pages 52-55).