Effect of Combining Moisture-assisted Drying on Lemon (Citrus limon (L.) Brum.): Physicochemical Properties, Antioxidant Capacities, and Sensory Evaluations

Abstract

Introduction

Moisture-assisted drying (MA-HAD) enhances agricultural products’ safety, functionality, and flavor and is applied to various fruits, including lemons, improving their market value and consumer acceptance.

Objectives

Evaluate MA-HAD’s impact on black lemons’ appearance, ingredients, antioxidant activities, flavor, and consumer acceptance.

Methods

Organic lemons (Eureka, Meyer, Assam, and Tahiti) were sliced and subjected to MA-HAD at 65 ± 2˚C and 80 ± 5% relative humidity for 7 days. After drying at 65 ± 2˚C and freeze-drying, samples were stored at -20˚C. Citric and ascorbic acids were analyzed using HPLC-UV. Hesperidin and limonin were quantified similarly. Antioxidant activities (DPPH, ABTS), total polyphenol, and flavonoid contents were measured. Sensory evaluation involved 120 panelists rating appearance, flavor, aroma, and overall acceptance using a 9-point hedonic scale.

Results

Water activity in MA-HAD lemons decreased significantly, with more uniform browning compared to HAD lemons. Browning and color differences were more pronounced in MA-HAD treated samples. Citric acid content decreased with increased heat, with Tahiti lemons having the highest initial content. Hesperidin content showed no significant difference between treatments but varied among species. The limonin content decreased in all lemons, with Eureka having the highest initial content. MA-HAD increased total polyphenol and flavonoid content, enhancing antioxidant activities. Sensory evaluation indicated that Eureka lemons were most acceptable, resembling commercial aged tangerine peels and black lemons. Tahiti, Meyer, and Assam lemons were less favored due to their pronounced sourness and bitterness.

Conclusion

The MA-HAD process enhanced lemon browning, increased total polyphenols, flavonoids, and antioxidant activity, while reducing ascorbic acid and limonin levels. Eureka lemons showed the best overall performance, aligning with commercial black lemons, and offering higher consumer acceptance due to improved functionality and reduced bitterness.

Graphical Abstract