ARS | Publication request: Effect of Different Time/Temperature Roast Combinations on Nutritional and Mechanical Properties of Peanuts

Submitted to: Institute of Food Technologies
Publication Type: Abstract Only
Publication Acceptance Date: June 10, 2011
Publication Date: June 10, 2011
Citation: 2011. Effect of Different Time/Temperature Roast Combinations on Nutritional and Mechanical Properties of Peanuts. Institute of Food Technologies. 1.

Technical Abstract: Peanuts in North America and Europe are primarily consumed after dry roasting. Standard industry practice is to roast peanuts to a specific surface color (Hunter L-value) for a given application; however, equivalent surface colors can be attained using different roast temperature/time combinations. Accordingly, a single lot of runner peanuts was roasted using five roast temperatures (147 ºC, 157 ºC, 167 ºC, 177 ºC, and 187 ºC) and various roast times to obtain 3 degrees of roast corresponding to L-values of 53+1, 48.5+1, and 43+1, for light, medium and dark roasts, respectively. Moisture content (MC), mechanical textural properties, tocopherol content, sugar content, and other characteristics were determined across the roasted peanut matrix. MC ranged from 0.41% for the 147 ºC dark roast to 1.70% for the 187 ºC light roast peanuts. At the same roast temperature, MC decreased as peanuts became darker; however, for a given color, MC decreased with decreasing roast temperature due to longer roast times required for specified color formation. Kramer shear cell indicated that peak force at compression positively correlated (R2=0.75) with MC. Total tocopherol contents ranged from 140 to 470 µg/g oil and decreasing MC correlated (R2=0.62) with increased total tocopherols. Total sugar contents of completely defatted flours ranged from approximately 7.4 to 8.6 g /100 g of defatted meal. Sucrose, glucose and fructose were significantly (p<0.05) influenced by roast color and temperature. The variation related to method of roasting for quality characteristics is sufficient to suggest influences on final product shelf life and consumer acceptability.