Evaluation of antioxidants in currant and gooseberry

Importance of the topic

Antioxidants in fruits play a key role in neutralizing free radicals and reducing oxidative stress in human cells. Berries such as currants and gooseberries are especially rich in compounds that can support health, making reliable measurement of their antioxidant capacity essential for nutrition research, breeding programs, and quality control in agriculture.

Objectives and overview of the study

This study compared the total antioxidant activity of various currant (black, red, white, pink) and gooseberry (red, white) cultivars grown under organic (EKO) and integrated pest management (IPM) systems. Using a rapid electrochemical approach, the work aimed to quantify differences among cultivars, cultivation regimes, and pigment intensity.

Methodology and instrumentation

• Plant material: Fruit samples were harvested at optimal maturity from experimental plantings in Holovousy, Czech Republic, under EKO and IPM management.
• Sample preparation: Berries were frozen, thawed, homogenized, and extracted with methanol/formic acid. Extracts were sonicated, centrifuged, filtered, diluted, and refrigerated before analysis.
• Antioxidant measurement: Flow injection analysis with coulometric electrochemical detection (FIA-ECD) quantified total antioxidant charge (Coulombs per gram fresh weight) by integrating signals from four sequential electrodes at 200, 400, 600, and 800 mV.

Použitá instrumentace

• Flow Injection Analysis system equipped with a CoulArray multichannel coulometric detector
• Ultrasonic bath (Bandelin Sonorex) for sample sonication
• Centrifuge (Hettich EBA 200) for phase separation
• High-speed homogenizer (Nutribullet)
• Syringe filters (0.22 µm Nylon) for sample clarification

Main results and discussion

Antioxidant activity varied strongly by cultivar and fruit color. Black currants exhibited the highest values (up to 0.785 C/g in ‘Triton’ under EKO), followed by red currants and then white and pink types. Gooseberries showed a similar pattern, with red cultivars (‘Karmen’, 0.117 C/g) exceeding white ones (‘Mucurines’, 0.045 C/g). Overall, organic (EKO) samples tended to yield higher antioxidant charges than IPM, though differences were within cultivar-specific variability and not always statistically significant at α=0.05.

Benefits and practical applications of the method

The FIA-ECD approach proved fast (up to 50 samples per hour), highly reproducible, and sensitive to cultivar and management effects. It facilitates high-throughput screening of breeding lines, quality control in fruit production, and rapid assessment of antioxidant potential in research and industry settings.

Future trends and potential applications

• Integration with chemometric and machine-learning tools for predictive modeling of antioxidant profiles.
• Application to a broader range of berries, fruits, and plant matrices to guide breeding for enhanced health benefits.
• Development of portable FIA-ECD instruments for field-based quality monitoring.
• Investigation of environmental and agronomic factors influencing antioxidant synthesis under organic and conventional systems.

Conclusion

Flow injection analysis with multichannel electrochemical detection offers a robust, rapid method for evaluating total antioxidant activity in small fruits. It revealed clear cultivar-dependent differences and a general trend toward higher antioxidant levels in organically grown samples. These insights support breeding efforts and quality assurance in berry production but should be interpreted in light of cultivar-specific variability.

Reference

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• Blasco A, Rogerio MC, González MC, Escarpa A. “Electrochemical Index” as a screening method to determine “total polyphenolics” in foods: a proposal. Analytica Chimica Acta. 2005;539:237-244.
• Benbrook C. Elevating Antioxidant Levels in Food through Organic Farming and Food Processing: An Organic Center State of Science Review. 2020.
• Kazimierczak R, Hallmann E, Rusaczonek A, Rembiałkowska E. Antioxidant content in black currants from organic and conventional cultivation. Electronic Journal of Polish Agricultural Universities. 2008;11.