UV-Vis Spectroscopy for Quality Assessment of Paprika as per ASTA Method 20.1

Significance of the Topic

Paprika’s color intensity directly influences its quality grading, consumer appeal and market value. Ensuring accurate and reproducible measurements of carotenoid pigments in paprika is vital for regulatory compliance, product authenticity and consistent supply chain quality control.

Objectives and Study Overview

This study demonstrates a streamlined workflow for determining paprika’s ASTA color value according to ASTA Method 20.1. Two commercial paprika samples were evaluated using a high-throughput multicell UV-Vis system to illustrate the speed, precision and standardization achievable in a routine laboratory environment.

Methodology and Instrumentation

Sample Preparation

• Certified reference material (Starna CRM 18294) was used to calculate the instrument correction factor (If).
• Test samples (~90 mg) were extracted in acetone (ACS grade) in 100 mL volumetric flasks, allowed to stand for 16 hours, then filtered by settling.
• Blank and sample extracts were measured in 10 mm quartz cuvettes.

Data Collection Parameters

• Wavelength range: 350–800 nm
• Analysis wavelength: 460 nm
• Spectral bandwidth: 2 nm
• Signal averaging time: 0.1 sec
• Data interval: 1 nm

Applied Instrumentation

• Agilent Cary 3500 Multicell UV-Vis spectrophotometer with eight stationary channels
• Agilent Cary UV Workstation software for data acquisition and End of Sequence analysis

Main Results and Discussion

The instrument correction factor (If) was determined by comparing NIST-declared absorbance (0.4934 Abs) with laboratory measurements over ten replicates, yielding a mean If of 1.0036 and an RSD of 0.019%. This confirmed instrument stability within ASTA requirements (RSD <1%).

Triplicate measurements of the two paprika samples produced corrected ASTA color values of approximately 103 and 61, respectively. The automatic End of Sequence analysis calculated absorbance at 460 nm, raw ASTA values and corrected values, simplifying data processing. Spectral overlays facilitated visual comparison of pigment profiles.

Benefits and Practical Applications

The multicell design enables simultaneous analysis of multiple samples and a reference, increasing throughput and reducing variability. Automated workflows in the UV Workstation software eliminate manual calculations and external tools, improving lab efficiency and traceability. The method supports quality grading in spice production, incoming raw material inspection and regulatory compliance checks.

Future Trends and Opportunities

Advances in software-driven automation and expanded multicell capacity will further accelerate high-volume analyses. Integration with laboratory information management systems (LIMS) and real-time reporting will enhance data integrity and decision support. Emerging fiber-optic and portable UV-Vis sensors may enable on-site quality checks at processing facilities.

Conclusion

The Agilent Cary 3500 UV-Vis system combined with Cary UV Workstation software offers a fast, reliable and standardized approach for paprika quality assessment per ASTA Method 20.1. Its high throughput, low variability and automated reporting streamline laboratory workflows and reinforce confidence in colorimetric grading.

Reference

• ASTA Method 20.1: Extractable Color in Capsicums and Their Oleoresins. Revised October 2004.