Nutritional and Phytochemical Characterization of Lemon Peel and Juice: Implications for Functional Food Applications

• Fatima Salih Mahdi1 Entisar Dawood Mustafa 2 Hussein Essa Hamad3

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This study aimed to conduct a comprehensive comparative evaluation of lemon peel and lemon juice (Citrus limon L.) with respect to their proximate composition, mineral profile, vitamin content, total phenolic content, antioxidant activity, and individual flavonoid composition. Fresh lemons obtained from local Iraqi markets were manually processed, and analyses were performed using standard AOAC methods, atomic absorption techniques, and HPLC. The results revealed significant compositional differences between peel and juice fractions. Lemon peel exhibited higher levels of protein, fat, fiber, ash, and total carbohydrates compared to juice. Mineral analysis showed that peel samples contained greater concentrations of calcium, magnesium, potassium, copper, and zinc, indicating superior micronutrient density. Vitamin profiling demonstrated that lemon peel was richer in B-complex vitamins and fat-soluble vitamins (A, E, and K), whereas lemon juice contained higher levels of vitamin C. Total phenolic content was markedly higher in lemon peel (77) than in juice (45), which was reflected in stronger antioxidant activity (76.42 vs. 65.45, respectively). HPLC analysis identified hesperidin and naringenin as the predominant flavonoids in lemon peel, followed by other flavonoids in general. This confirms that the peel is a concentrated source of bioactive compounds with significant antioxidant and nutritional potential.. The valorization of lemon peel may contribute to functional food development and sustainable agro-industrial practices.

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