29D-16 |
Effect of end-over-end thermal processing on heat penetration paramters and quality of canned potatoes |
B. Jobe and H. S. RAMASWAMY. Dept. of Food Science & Agricultural Chemistry, McGill Univ., Macdonald Campus, 21111 Lakeshore Rd., Sainte-Anne-de-Bellevue, QC H9X 3V9 Today’s consumers are interested in products that are safe and appealing in quality. This demands efforts to optimize thermal processing conditions for low acid foods. Data on thermal process parameters fh,jch etc are essential for determining the process time and optimal processing conditions for heat sterilization. These parameters are influenced by many factors related to the product, package and process. The objectives of this study were to investigate the effects of selected thermal process variables (temperature, rotational speed, can size and nature of the carrier fluid) on heating behavior of canned potatoes and their influence on product quality. Heat penetration tests were carried out using a full factorial design of experiments. Prepared potatoes were filled (68.5%w/w) into 211x400, 307x409 and 401x411 cans. Cans were toped with water (with 2% sugar + 2% salt) or 1% Carboxymethyl cellulose (CMC) solution, sealed and subjected to end-over-end rotational processing in a pilot-scale rotary, single cage full water immersion retort. Temperature signals at the particle center were measured at 10-s intervals using flexible copper-constantan thermocouple fitted to a HP data logger. Increasing rotational speed from 0 to 20 rpm or using smaller can size significantly (p<0.05) reduced the fh and jch values while the effect of temperature was not conclusive. None of the factors under investigation showed significant effect on the jcc. All factors that enhanced heat transfer rates resulted in higher process lethality (Fo) and cook value (Co). Processing at high temperature, high rotational speed and small can size reduced the process time significantly and gave products of better color and texture as indicated by the color parameters (L, a and b) values and Co/Fo ratio. Lower ratio of Co/Fo is indicative of conditions promoting better quality in thermal processing.
Session 29D, Food Engineering: Thermal processes
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