Chicken breast patties were processed in an air convection oven at air temperatures of 149 to 218 C, air velocities of 7.1 to 12.7 m3/min, and air relative humidities of 40 to 95%. The air humidity was controlled via introducing steam into the oven. The patties were processed to a final center temperature of 50 to 80 C. Heat flux, heat transfer coefficient, moisture loss in the cooked chicken patties, the product yield, and the changes of soluble proteins in the product were evaluated for the cooking system. During cooking, heat flux varied with the processing time. Heat flux increased with increasing air humidity. The effective heat transfer coefficient was obtained for different cooking conditions. Air humidity in the oven affected the heat transfer coefficient. The moisture loss in the cooked products increased with increasing the final product temperature and the oven air temperature. The soluble proteins in the cooked patties decreased with increasing the final product temperature. Increasing humidity increased heat transfer coefficient and therefore reduced cooking time. Reducing oven temperature, reducing internal temperature, and increasing air humidity increased the product yield. Soluble proteins might be used as an indicator for the degree of cooking. The results from this study are important for evaluating commercial thermal processes and improving product yields.

Commercially formulated meat products, including chicken patties, chicken tenders, franks, beef patties, and blended beef and turkey patties, were obtained from processors. Each product was inoculated with 7 to 8 logs of Salmonella (Senftenberg, Typhimurium, Heidelberg, Mission, Montevideo, and California) or Listeria innocua. The inoculated meat samples were heat treated at 55 to 70 degrees C. At each temperature, the decimal reduction time (D) was obtained by linear regression of survival curves. Values of D and the temperature difference required for the thermal inactivation curve to drop a logarithmic cycle (z) were determined for the Salmonella serotypes and L. innocua in each product. At 55 to 70 degrees C. for the five tested products, the D-values for the Salmonella serotypes and L. innocua were 26.97 to 0.25 min and 191.94 to 0.18 min, respectively, and their z-values were 7.60 to 9.83 degrees C and 4.86 to 8.67 degrees C, respectively. Significant differences were found for the D- and z-values among the five products. This study will better enable processors to determine the process lethality of pathogens in commercial meat products.

Functional properties of the soy protein need to improve to have better applications in food industry. Alkali extracted and acid precipitated soy protein isolate (SPI) was glycosylated using D-glucose (G) and Xanthan gum (X) via Maillard reaction to improve solubility. The effects of SPI to G and SPI to X ratios (SPI:G = 2:1, 1:1, and 1:2; SPI:X = 100:1 and 10:1) and incubation time (0, 6, 12, and 24 h) on the solubility and functional properties of glycosylated SPI were evaluated. The SPI:G ratio of 1:2 yielded a maximum degree of glycosylation of 71.1 %. The solubility of SPI after glycosylation significantly increased (P<0.05) at pH 4.0-8.0 compared to SPI alone. Although the emulsion stability of glycosylated SPIs has not significantly increased (P>0.05), the emulsifying activity improved significantly (P<0.05). Glycosylation with SPI-X at a ratio of 10: 1 showed maximum emulsifying activity of 191.6 m 2 /g (SPI alone: 66.3 m 2 /g). Moreover, the SPI:X (ratio of 100:1) showed the maximum foaming activity (205 mL) compared to SPI alone (155 mL). The foaming stability of SPI (2.6 %) increased to 5.5 and 8.2 % when using xanthan gum at the ratio of 100:1 and 10:1, respectively. Glycosylated SPI with enhanced emulsifying and foaming properties has potential to improve the functional quality of the food products.

Beef/turkey blended patties, containing 10 7 to 10 8 cfu/g of Salmonella Senftenberg or Listeria innocua, were battered and breaded. The effect of frying (177 °C) and air convection cooking (288 °C) on thermal inactivation of S. Senftenberg and L. innocua was evaluated. A model was obtained to correlate product internal temperature with frying and oven cooking time. Cooking method significantly affected thermal history and subsequently the thermal inactivation of S. Senftenberg and L. innocua. The effect of frying time interacted with oven cooking time. Increasing frying time reduced the oven cooking time. Mathematical models were developed to correlate the survival rate of S. Senftenberg or L. innocua with frying and oven cooking time.

Fully cooked chicken breast strips were surface inoculated to contain 9 log10 (CFU/g) Salmonella Senftenberg or Listeria innocua. The inoculated products were vacuum packaged in 0.2-mm-thick barrier bags (241 by 114 mm), then steam pasteurized at 88 degrees C in a continuous process for 26 to 40 min or in a batch process for 33 to 41 min. After the treatments, the products were analyzed for the survivors of Salmonella or Listeria. The models were developed to correlate the surviving rate of Salmonella and Listeria with cooking time for both continuous and batch processes. A cooking time of 34 min was needed to achieve 7 logs of the reduction in a batch process. To achieve the same log reduction, a longer (6 min) cooking time was needed in a batch process than in a continuous process. The results from this study will be useful for processors to evaluate postcooking treatment procedures for ready-to-eat meat products.