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Drying behavior of a single baking biscuit was modeled using unsteady state, anisotropic, two dimensional, simultaneous heat and mass balances. Solutions of these equations agreed well with the experimentally determined temperature and the moisture data. Modeling revealed that in the outer sections of the baking biscuit conduction and diffusion were the dominant heat and mass transfer mechanisms, respectively. In the central section of the biscuit the gas cells cracked with the increased vapor pressure and the upward volume expansion, then air/vapor enclaves were formed among the horizontal dough layers in the radial direction. the dominant heat and mass transfer mechanisms in the central section of the biscuit were convection. Presence of two different regime zones in a baking biscuit may have important consequences concerning the strength of the commercial products against crumbling during marketing and consumption.

Texture of acidified canned carrots was evaluated using a shear compression procedure. Carrots canned with as littlc as 0.77% gluconic acid in the brine retained firmer texture than those packed without acid. Softening phenomena of acidified carrots do not appear to be consistent with a two substrate first order rate expression model.

Spores of the putrefactive anaerobe (P.A.) 3679 are widely used in inoculated pack studies designed to evaluate the adequacy of heat processes for low acid foods. For this purpose, it is essential to have the ability to repeatedly grow large amounts (>106) of test spores with comparable heat resistance. Beef heart infusion broth fortified with 1.0% tryptone, 1.0% gelatin, 0.05% glucose, 0.4% dibasic POtassium phosphate, 0.3% sodium citrate, and either 0.5% isoelectric casein or 1.5% skim milk powder, in the presence of beef heart particles was found to be dependable for producing >109 heat resistant spores/liter medium when incubated 2 wk at 30°C followed by 1 wk at 20°C. With the beef heart debris either remaining or absent after two washing, the heat resistance of the spores did not change during 1 yr of storage at 4°C.

Apricots, clingstone and freestone peaches packed in tin-free steel cans with up to 1.1% gluconic acid in the syrup retained better color than fruits packed without the acidulant. Up to 0.44% by weight gluconic acid did not affect heat resistance of peroxidase/polyphenoloxidase enzyme systems in apricots. Requirements for heat inactivation of enzymes increased with fruit maturity, from Frmc = 1.3 min with z = 16°C in canning ripe, to Franc = 7 min with z = 61.5"C in soft ripe apricots. Enzyme regeneration occurred within 48 hr. Methods tested for measuring enzyme activity arc discussed.