Investigation of Strategies to Reduce Exposure to β-Carboline Alkaloids in Food

Abstract

β-Carboline (βC) alkaloids are indole alkaloids that occur naturally in foods, and they have been reported to have both pharmacological effects and toxicity. We monitored the levels of six types of βC alkaloids in various food products and found significant variations within the same food. This study was conducted to develop measures for minimizing dietary exposure to βC alkaloids, specifically focusing on garlic and broccoli. We compared the detection levels of Harman in whole garlic, peeled garlic, and minced garlic based on their distribution and storage forms. For broccoli, the detection levels of Norharman were compared between fresh and frozen products, considering their distribution forms. Each sample was analyzed up to Day 28 with distinct storage temperatures. Results indicated that, regardless of storage temperature or duration, minced garlic exhibited the highest levels of Harman. Fresh broccoli showed greater Norharman levels compared to frozen broccoli. Additionally, minced garlic tended to have increased detection levels with longer storage periods at room temperature and refrigeration. In contrast, frozen broccoli showed a tendency for increased Norharman levels with prolonged storage. For minced garlic, freezing can minimize exposure to Harman, while for broccoli, blanching followed by freezing is required to minimize exposure to Norharman. The significant variations found in this study are presumed to be due to enzyme activity caused by microbial growth and differences in the manufacturing process. Further studies are needed to identify the causes of these variations and to develop strategies for reducing β-Carboline alkaloids in food products.