https://doi.org/10.17113/ftb.63.01.25.8474

article in press

Thermal Aging of Black Garlic Enhances Cellular Antioxidant Potential Through Nrf2-Mediated Pathway Activation

Shan-Shan Yu¹, Yung-Lin Chu², Yen-Chen Tung³ and Zheng-Yuan Su^1*

¹Department of Bioscience Technology, Chung Yuan Christian University, Taoyuan City 320314, Taiwan, Republic of China

²Department of Food Science, National Pingtung University of Science and Technology, Pingtung County 912301, Taiwan, Republic of China

³Department of Food Science, National Ilan University, Yilan County 260007, Taiwan, Republic of China

Copyright © 2024 This is a Diamond Open Access article published under CC-BY licence. Copyright remains with the authors, who grant third parties the unrestricted right to use, copy, distribute and reproduce the article as long as the original author(s) and source are acknowledged.

Article history:

Received: 14 December 2023

Accepted: 11 February 2025

Keywords:

garlic; Maillard reaction; liver; Nrf2; oxidative stress; antioxidant properties

The content of this publication has not been approved by the United Nations and does not reflect the views of the United Nations or its officials or Member States.

Summary:

Research background. Oxidative stress plays a crucial role in various diseases, including chronic hepatitis, cirrhosis, and liver cancer, which are significant causes of mortality worldwide. Liver cell injury resulting from oxidative stress contributes to the development of these diseases. Garlic is known for its diverse physiological activities, and black garlic, produced through thermal aging of raw garlic, has gained attention for its biological properties.

Experimental approach. This study explores the hepatoprotective potential of black garlic prepared using an electric cooker. The investigation covers weight loss, brown index, free amino acids, free-reducing sugar content, total phenolic compounds, and DPPH radical scavenging ability. Additionally, sensory assessment indicates a preference for a black garlic sample. The study also examines Nrf2-ARE pathway activation in HepG2-C8 cells and evaluates protective effects against H₂O₂-induced damage.

Results and conclusions. The findings indicated that black garlic lost weight, possibly due to water loss and the Maillard reaction, which led to an increase in brown index and decreased free amino acids. However, the free-reducing sugar content increased. After 14 and 21 days, black garlic showed an increase in total phenolic compounds and a better ability to scavenge DPPH radicals. Significant activation of the Nrf2-ARE pathway was observed in HepG2-C8 cells. The sensory evaluation showed a preference for the 14-day-aged black garlic. The Nrf2 pathway can be effectively activated in HepG2 cells by 14-day aged black garlic extract, resulting in protection against H₂O₂-induced damage.

Novelty and scientific contribution. Our research reveals the significant impact of thermal aging on black garlic, highlighting its enhanced antioxidant properties. A straightforward approach has been established to prepare black garlic that is more potent and healthier, with potential applications in liver protection and oxidative stress-related diseases.