Recent overview of kaffir lime (Citrus hystrix DC) dual functionality in food and nutraceuticals

Kaffir lime, less popular than most citrus species with fresh edible fruits, is considered a minor citrus in its native Southeast Asia, where cultivation is also less intensive. This review presents a novel perspective regarding kaffir lime, highlighting its potential utility not only as a culinary spice but also as a promising nutraceutical. Kaffir lime essential oils (KEOs) is a key source of citronellal, citronellol, sabinene, and terpinene-4-ol—compounds typically found in lemongrass and black pepper but rarely present in other citrus varieties. Citronellal, citronellol, and terpinene-4-ol act as antimicrobial agents, are used in aromatherapy, and function as repellents. Citronellal and citronellol also provide natural fragrance and preservative properties. Additionally, sabinene has the potential to prevent muscle atrophy. Although kaffir lime is known for its KEOs content, its phytochemical composition can vary depending on the plant part and extraction method. KEOs such as linalool and citronellal produce sweet, floral, and fresh aromas. Consequently, kaffir lime is often used to enhance the flavor of food and beverage products. A potential byproduct of kaffir lime fruit is pectin used as a thickening and stabilizer agent in the food industry. The biological benefits of pectin include lowering cholesterol, controlling blood sugar, and reducing the risk of digestive cancers. Moreover, various active components in kaffir lime, including vitamin C, are crucial for radioprotection, boosting immunity, and improving iron absorption. This overview highlights the application of kaffir lime and its derivative product in aromatherapy, antioxidant properties, anticancer effects, gastrointestinal health, wound healing, dietary fiber, aroma and flavor, beverages, and natural preservation. Furthermore, future concepts regarding the engineering of nanoparticles from kaffir lime for drug delivery and functional food release systems will also be discussed.