Date of Award
Master of Science
Food Science and Technology
Svetlana Zivanovic, Arnold Saxton
When available, wet pack peaches are produced by repackaging sliced and/or diced canned clingstone peaches into a 5-ounce MRE pouch, followed by a thermal process. In this study, wet pack diced peaches were processed in 5-ounce pouches using canned, fresh, and frozen peaches as the raw material. Calcium chloride was added at 0.0 or 0.5% (w/w) to the pouches. The pouches were then stored at 37°C for six months or 50°C for six weeks. The peaches were evaluated for texture, drained weight, pH, brix and sensory evaluations.
The canned peaches were not significantly different from wet pack peaches processed using frozen and fresh peaches for overall liking when stored at 37°C for six months. Based on the inability of panelists to differentiate between peach types for overall liking, this study suggests that producers should continue to use canned clingstone peaches as the peach source for wet pack peaches.
When calcium chloride was applied to wet pack peaches before thermal processing at 0.5% w/w, a significant increase was seen in the firmness of wet pack peaches after processing. Peaches treated with calcium chloride did not lose firmness as quickly when stored at 50°C for six weeks, but showed no difference in firmness loss rates when stored at 37°C for six months. Sensory analysis of the samples stored at 37°C for six months showed an improvement in firmness scores but a drastic decline in overall acceptance due to the impact of flavor scores.
Multiple levels of calcium chloride showed increased firming effects as the percentage of calcium chloride increased, with negative effects on flavor as the percentage increased. Flavor was not significantly affected by calcium chloride at 0.125% in sensory analysis. This study concludes that to optimize flavor and firmness of wet pack peaches, calcium chloride should only be added at a level up to 0.125%(w/w) that will result in a final pH ≥3.85.
Morse, Lee Charles, "Evaluation of Shelf-Life Improvements of Wet Pack Clingstone Peaches Designed for Military Operation Rations by Addition of Calcium Salts. " Master's Thesis, University of Tennessee, 2011.