CHARACTERIZATION OF LIPIDS AND EVALUATION OF ELEMENTAL COMPOSITION OF AVOCADO (Persea americana Mill) CULTIVARS GROWN IN MURANG’A COUNTY, KENYA

Abstract

Globally, over two billion people suffer from malnutrition and chronic micronutrient deficiencies, representing 7% of the disease burden. Avocado, a nutrient-dense fruit rich in lipids and essential minerals, has potential to alleviate such deficiencies. This study focused on characterizing the lipid content and determining the elemental composition of pulp and seed from four avocado cultivars—Fuerte, Hass, Pinkerton, and Giant—cultivated in Murang’a County, Kenya, a region with optimal climate and soil conditions for avocado farming. Fruits were sampled from three agro-ecological zones (1400–2200 m altitude). Proximate analysis was conducted on fresh pulp, while oil from dried pulp was extracted using petroleum ether. Physicochemical properties of the oil—including specific gravity, acid value, saponification value, iodine value, and peroxide value—were analysed. Fatty acid methyl esters were derived and analysed using GC-MS to determine fatty acid composition. Mineral element profiles in pulp and seed were quantified using Atomic Absorption Spectroscopy. Data were statistically analysed using ANOVA and Tukey’s HSD test (P < 0.05). Results revealed moisture content ranged from 59.30–84.31%, ash 0.96–1.53%, dietary fibre 1.83–6.43%, and oil 59.44–75.32% among cultivars. Oil properties varied: specific gravity (0.85–0.92), acid value (0.18–0.98 mg KOH/g), saponification value (123.42–187 mg KOH/g), iodine value (54–107 g I₂/100g), and peroxide value (0.9–2.3 meq O₂/kg). The fatty acid profile showed presence of seven fatty acids, predominantly oleic and palmitoleic acids. Fuerte from zone 1 recorded the highest oleic acid content (78.62%), followed closely by Giant (78.52%). Mineral analysis showed potassium (169.2–653.7 mg/100g) and calcium (14.12–49.95 mg/100g) were most abundant in pulp, while iron (0.429–0.786 mg/100g) and zinc (0.049–1.59 mg/100g) were more concentrated in seeds. Statistically significant variations across cultivars and regions led to the rejection of the null hypothesis. The findings demonstrate substantial nutritional variability among avocado cultivars and highlight the potential of Murang’a-grown avocados as sources of health-promoting lipids and minerals. These insights are valuable for nutritional labeling, product development, and informed cultivar selection by producers and consumers.