Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: June 21, 2009
Publication Date: June 21, 2009
Citation: Yang, J., Pan, Z., Brandl, M., Mc Hugh, T.H., Bingol, G., Wang, H., Olson, D.A. 2009. Infrared Heating for Improved Safety and Processing Efficiency of Dry-Roasted Almonds. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). ASABE Paper #096047. p. 1-13. St. Joseph, Mich. Interpretive Summary: This research developed a new processing method for almond roasting. The sequential infrared and hot air roasting has shown significantly improved food safety of roasted almonds and reduced roasting time. This new roasting method can be implemented in the almond industry easily.
Technical Abstract: The use of infrared (IR) heating technology was investigated for improving safety and processing efficiency of dry-roasted almonds. Almonds were roasted at 130, 140 and 150°C with three different methods: IR heating, sequential infrared and hot air (SIRHA) heating, and traditional hot air (HA) heating. The heating rate and color change of almonds under different heating methods and temperatures were evaluated. The value of overall color change was used as the indicator of degree of roasting. Pediococcus spp. NRRL B-2354 was used as a surrogate for Salmonella Enteriditis PT 30 and inoculated to raw almonds for evaluating the pasteurization efficacy of different processing methods and conditions. When SIRHA roasting was used for producing medium roasted almonds, 4.10-, 5.82- and 6.96-log bacterial reductions were achieved by using 130, 140 and 150°C roasting temperatures with roasting times of 21, 11 and 5 min., respectively. Furthermore, the SIRHA roasting process resulted in 38%, 39% and 62% time saving compared to traditional HA roasting at the same corresponding roasting temperatures. We concluded that SIRHA roasting is a much superior roasting method for producing roasted almonds that meet the pasteurization requirement and has the potential to reduce costs due to reduced roasting time compared to current hot air roasting.