NUTRITIONAL COMPOSITION OF BLANCHED AND SODIUM HYDROGEN SULPHATE (NaSO4) TREATED DUCKWEED.

Abstract

Duckweed (Lemna minor L.) is emerging as a sustainable and nutrient-rich food source, particularly appealing due to rising animal protein costs and interest in plant-based diets; hence, duckweed could serve as an alternative and cheap protein source for human and animal feed. This study examined the effects of various pretreatments (blanching and soaking in Sodium hydrogen sulphate solution) and drying methods (oven-drying, sun-drying, freeze-drying) on the nutritional and antinutritional profiles of duckweed. Nine sample groups were prepared: OB: Oven-dried, blanched, OS: Oven-dried, NaHSO4-treated, OC: Oven-dried, untreated control, SB: Sun-dried, blanched, SS: Sun-dried, NaHSO4-treated, SC: Sun-dried, untreated control, FB: Freeze-dried, blanched, FS: Freeze-dried, NaHSO4-treated, FC: Freeze-dried, untreated control samples and analyzed using standard methods for nutrient content, including proximate, minerals, vitamins (A, E, C), and amino acids. Results indicated that freeze-drying was the most effective method for preserving nutrients, yielding higher levels of amino acids, minerals, and vitamins. Sun-drying and oven-drying with Sodium hydrogen sulphate (NaSO4) treatment moderately retained proteins (ranging from 10.15 to 19.89 %) but varied in fiber and lipid content. The study found considerable variations in nutritional content among the samples, with moisture levels ranging from 7.01% in freeze-dried NaHSO4-treated samples to 11.71% in sun-dried controls. Carbohydrates were highest in sun-dried blanched samples, while crude fiber peaked in oven-dried NaHSO4 samples. Protein content varied significantly, with values from 11.33% in sun-dried NaHSO4 samples to 19.89% in oven-dried controls. Overall, freeze-drying is recommended for preserving essential nutrients in duckweed, while oven-drying is better for non-essential amino acids. Sodium sulphate treatment maintained vitamins during freeze-drying but slightly reduced amino acid levels and altered mineral content.