Compositional and mechanical properties of peanuts roasted to equivalent colors using different time/temperature...

Area of Science:

• Food Science
• Agricultural Science
• Nutritional Science

Background:

• Peanuts are commonly dry roasted to a specific surface color (Hunter L-value) in North America and Europe.
• Varying roast temperature/time combinations can achieve equivalent surface colors, potentially impacting peanut quality.

Purpose of the Study:

• To investigate how different roast temperature/time combinations affect peanut composition and quality parameters.
• To determine the influence of roasting conditions on moisture content, tocopherols, glucose, fructose, soluble protein, lysine, and texture.

Main Methods:

• Runner peanuts were roasted at five temperatures (147-187 °C) to three Hunter L-values (light, medium, dark).
• Moisture content, tocopherol, glucose, fructose, soluble protein, lysine, and peak compression force were analyzed.

Main Results:

• Moisture content varied significantly with roast conditions, correlating strongly with tocopherols, soluble protein, and texture.
• Lower temperatures and darker roasts resulted in higher tocopherol content.
• Glucose content depended on roast color and temperature, while fructose was only temperature-dependent.
• Soluble protein decreased with darker roasts, and lysine decreased with increasing roast color.

Conclusions:

• Roast temperature and time significantly influence peanut composition, including key nutrients and physical properties.
• Variations in roasting conditions can affect final product shelf life and consumer acceptability.
• Optimizing roast profiles is crucial for achieving desired peanut quality attributes.