Infrared Roasting and Pasteurization

Conventional hot air roasting method for almonds at temperatures of 130 to 155ºC has the shortcomings of long roasting time and high processing cost and is unable to meet the pasteurization requirement. Our research team developed a new Sequential IR and hot air (SIRHA) roasting approach for almonds at 130 to 150ºC for improved microbial reduction and reduced roasting time. SIRHA dry-roasting of pistachios resulted in saving of processing time and inactivation of bacteria without affecting the texture, flavor and oil quality. Main findings from this research include: 

  • IR heating almonds to 100 ºC with subsequent holding at 90 ºC for 10 min provided more than 5.5-log reduction of Pediococcus number on the kernels.
  • No significant differences were found in appearance, texture, flavor and overall quality of pasteurized almonds compared with untreated samples.
  • Sequential IR and hot air (SIRHA) roasting is an effective and low cost method for producing pasteurized almonds with similar quality, but less time compared to hot air roasting.

Read more articles at: Infrared-Based Approach Explored for Keeping Almonds Safe to Eat

Selected Publications:

Venkitasamy, C., C. Zhu, M.T. Brandl, F. J.A. Niederholzer, R. Zhang, T.H. McHugh, and Z. Pan. 2018. Feasibility of using sequential infrared and hot air for almond drying and inactivation of Enterococcus faecium NRRL B-2354. LWT – Food Science and Technology. 95:123-128.

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