New Study Reveals Optimal Storage Conditions for Preserving Health-Promoting Anthocyanins in Fruit Extracts

Recently, a team of researchers from the University of Craiova in Romania explored the stability and degradation behavior of anthocyanins. This study, which was published in the journal Antioxidants (Basel), used ultraviolet–visible (UV-vis) spectrophotometry to measure the anthocyanin content of several fruits, which allowed them to determine the optimal storage conditions (1).

What are anthocyanins?

Anthocyanins are plant-derived polyphenolic compounds widely known for potent antioxidant properties and associated health benefits (2). Anthocyanins are colored water-soluble pigments that are responsible for the red, purple, and blue hues in many fruits and vegetables (2). Beyond their aesthetic contribution, these compounds have garnered scientific interest because of their demonstrated antimicrobial, anti-obesity, cardioprotective, and anticarcinogenic effects. Given their role as key dietary antioxidants, understanding their concentration in foods and their stability under various conditions is essential for maximizing health benefits and maintaining product quality in consumer goods (1).

What did the researchers test in their study?

In their study, the researchers analyzed the total anthocyanin content (TAC) of several fresh fruits using the pH differential method and UV–vis spectrophotometry. Their analysis ranked the TAC levels in descending order as follows: blackcurrants, blackberries, blueberries, raspberries, strawberries, and plums (1). The highest anthocyanin content was found in blackcurrants, with 256 mg per 100 grams of fresh fruit, while plums contained the lowest, at just 12 mg per 100 grams (1).

A bowl of fresh blueberries sits on a rustic wooden table, several berries scattered nearby. Generated with AI. | Image Credit: © Collection - stock.adobe.com

Another aspect of this study concentrated on blueberries. These fruits are rich in anthocyanins. For this part of the study, the researchers extracted anthocyanins into an ethanol/water solution and studied their degradation under four experimental storage conditions: direct sunlight, shadow (ambient light), complete darkness, and refrigeration (cold test) (1). Their goal was to determine how environmental factors like light exposure and temperature affect the stability of these valuable compounds (1).

What were the results of the study?

The researchers uncovered some important results about the blueberry anthocyanins. When stored under direct sunlight, the blueberry anthocyanins underwent rapid and extensive degradation, with 97.4% of color lost after just 10 days (1). In contrast, cold storage preserved the extract’s color and anthocyanin content far better, resulting in only 2.4% degradation over the same time frame (1). The researchers also determined that better results were achieved when the blueberry anthocyanins were stored in complete darkness compared to shadow and dark storage.

These findings were supported by kinetic modeling of the degradation reactions. The team observed that anthocyanin degradation followed zero-order kinetics under sunlight exposure, meaning the rate of degradation remained constant over time regardless of the concentration (1). However, under the other three storage conditions, the degradation followed pseudo-first-order kinetics, where the degradation rate was dependent on anthocyanin concentration (1). This distinction is important for predicting shelf-life and designing storage systems that minimize anthocyanin loss.

What are the next steps in this research?

The next steps in this research extend to the food industry. As anthocyanins gain popularity as natural additives in functional foods, dietary supplements, beverages, and cosmetics, optimizing their stability during production and storage becomes critical. These findings demonstrate that avoiding light exposure and maintaining cool temperatures are key strategies for preserving the integrity of anthocyanin-containing products (1).

In addition to offering a degradation mechanism for blueberry anthocyanins, the study also touches on the potential health impacts of anthocyanin degradation products, noting that such byproducts may differ in biological activity from the parent compounds (1). Proper storage of anthocyanin-rich extracts not only preserves visual appeal but also ensures their therapeutic potential remains intact.

References

1. Ionescu, C.; Samide, A.; Tigae, C. Trend in Detection of Anthocyanins from Fresh Fruits and the Influence of Some Factors on Their Stability Impacting Human Health: Kinetic Study Assisted by UV–Vis Spectrophotometry. Antioxidants (Basel) 2025, 14 (2), 227. DOI: 10.3390/antiox14020227
2. Khoo, H. E.; Azlan, A.; Tang, S. M.; Lim, S. M. Anthocyanidins and Anthocyanins: Colored Pigments as Food, Pharmaceutical Ingredients, and the Potential Health Benefits. Food Nutr. Res. 2017, 61 (1), 1361779. DOI: 10.1080/16546628.2017.1361779