Heat penetration data were obtained for a canned food model (gelatinized waxy maize starch) during processing in an agitating retort under various conditions to evaluate the effect of process variables on the heat penetration parameters (f$ sb{ rm h}$ and j$ sb{ rm ch}$) and resulting process lethality (F$ sb{ rm o}$) and cook value (C$ sb{ rm o}$). Overall heat transfer coefficient (U$ sb{ rm o}$), Hunter L, a and b values were determined. The study indicated that f$ sb{ rm h}$, j$ sb{ rm ch}$, F$ sb{ rm o}$, C$ sb{ rm o}$ and U$ sb{ rm o}$ were influenced (p $<$ 0.05) by all process variables except can headspace. Retention percentage of thiamin, ascorbic acid and chlorophyll at each process condition was estimated using the heat penetration data and documented D and z values for each quality factor. Results confirm better retention of quality factors at higher temperatures and higher rotation speeds. / Rheological changes associated with the starch were evaluated in relation to different factors and were well described by the Power law model. Apparent viscosity of the processed product was related to the cook value of the process. / Fresh vegetables were canned and subjected to end-over-end rotation. Heating times were adjusted to give approximately the same process lethality (F$ sb{ rm o}$ = 10 minutes). Processing under higher temperatures and higher rotation speeds resulted in better retention (p $<$ 0.01) of vegetable texture, while only temperature (higher the better) had a desirable effect on color. / Buffered aqueous mixtures of ascorbic acid and thiamin were sealed in glass vials and cans. At each temperature, rotation speed did not have a significant effect on the retention of either vitamin. Processing at 110$ sp circ$C yielded significantly lower retention (p $<$ 0.01) of both vitamins than at 120$ sp circ$C and 130$ sp circ$C. Estimated ascorbic acid and thiamin retention using experimental time-temperature data and published kinetic parameters showed fairly good agreement with experimental data.

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Graduation date: 1951