From Agricultural Waste to Health-promoting Salts: Peanut Shells and Corn Cobs as Alternatives to Table Salt

Abstract

Background: Excessive consumption of sodium chloride is associated with hypertension and cardiovascular diseases, while large amounts of agricultural residues such as peanut shells and corn cobs remain underutilized and contribute to environmental pollution. Valorizing these biomasses into mineral-rich plant-based salts may provide a sustainable and healthier alternative to conventional table salt. Aims : This study proposes an innovative approach for producing plant-based mineral salts from peanut shells and corn cobs, aiming to partially replace sodium chloride (NaCl) while addressing environmental and health concerns associated with agricultural residues. Study design. The study focused on the transformation of agricultural residues into mineral salts and the physicochemical characterization of the obtained products. Place and Duration of Study: The biomasses were processed under laboratory conditions through drying, incineration, leaching, and evaporation procedures. Methodology : The biomasses were oven-dried at 105 °C and incinerated at 550 °C. The resulting ashes were leached with distilled water and the filtrates were evaporated at 105 °C to obtain crystalline salts, with average extraction yields of 19.13% and 48.11% for peanut shells and corn cobs, respectively. ICP-OES analysis revealed a high potassium content in both salts : peanut shells K (468.10 mg/g), Na (5.60 mg/g), Ca (1.22 mg/g), Mg (0.07 mg/g); corn cobs K (411.20 mg/g), Na (3.63 mg/g), Ca (2.13 mg/g), Mg (0.04 mg/g). Results : The Na/K ratio was extremely low (0.01) in both cases. Anion analysis indicated significant chloride contents (44.37 mg/L and 49.70 mg/L), while iodide was not detected. The predominance of potassium suggests a strong potential for these salts as healthier alternatives to NaCl. Conclusion : These findings indicate that plant-based salts derived from peanut shells and corn cobs could serve as promising alternatives to conventional table salt. However, iodine fortification is required prior to consumption to prevent iodine deficiency disorders.