[Evaluation of walnut by terahertz nondestructive technology]

Area of Science:

• Agricultural Science
• Spectroscopy
• Materials Science

Context:

• Walnut quality assessment is crucial for the food industry.
• Current methods for detecting walnut spoilage and measuring shell thickness can be destructive or inefficient.
• Terahertz (THz) time-domain spectroscopy (TDS) offers a non-destructive approach for material analysis.

Purpose:

• To develop and validate a non-destructive method for evaluating walnut quality, including spoilage detection and shell thickness measurement, using THz-TDS.
• To compare THz spectra of normal, moth-eaten, and moldy walnuts to identify distinguishing features.
• To establish a novel formula for calculating walnut shell thickness within a THz-TDS system.

Summary:

• Terahertz time-domain spectroscopy (THz-TDS) was employed to analyze walnut quality. Differences in THz absorption peaks allowed for the rejection of spoiled walnuts (moth-eaten, moldy).
• A combined transmission- and reflection-type THz-TDS system was utilized to develop a new formula for determining walnut shell thickness, achieving a 3.7% relative error.
• The study demonstrates the capability of THz-TDS to nondestructively evaluate walnut quality based on physical and chemical indicators derived from spectral data.

Impact:

• Provides a non-destructive, rapid, and accurate method for walnut quality control, potentially reducing waste and improving product safety.
• Enables precise measurement of walnut shell thickness, which can be an indicator of kernel development and overall quality.
• Advances the application of THz spectroscopy in agricultural product analysis and quality assessment.