Physicochemical and Functional Properties of Edible Dung Beetle Larvae (Scarabaeus satyrus) Flours and Oils and their Significance in Human Nutrition

The potential of edible insects in alleviating the nutritional challenges facing humans has led to an increased interest in their utilization. Edible insects contain substantial amounts of protein and fats, which are very important macronutrients that confer useful functional and physicochemical properties to foods. However, the functional properties of these nutrients have not been given sufficient attention, limiting their use as ingredients in diets and food products. Processing of insects converts them into an ingredient that can be added to various foods, improving their acceptability in terms of flavor, taste, and nutritional content. Popular processing methods for edible insects include frying, boiling, oven drying, roasting, smoking, and toasting. These thermal treatments reduce the insect water content, enabling them to be milled into powders. This study set out to investigate the fatty acid profile, protein digestibility, and physicochemical and functional properties of powders and oils of edible dung beetle (Scarabaeus satyrus). The dung larvae were collected from three counties in Western Kenya. They were cleaned and subjected to drying and milling, then analyzed. Results indicated that protein digestibility ranged between 64.27-70.03%. The dominant unsaturated fatty acid was Oleic (45.71±2.45%), while the main saturated fatty acid was Lauric (45.43 ±0.8%). The saponification value of the oils ranged between 127.94 -130.17 mgKOH/g oil, Acid value (41.96-44.11 mg KOH/g oil), peroxide value (4.23-3.8 Meq.thio / kg sample), refractive index (1.41-1.44/25ºC) and Iodine value (77.89-88.02 g I/100g). Functional properties of the powders showed high lipophilic (332.45±19.73%) and moderate (1.11±0.14 ml/g) hygroscopic tendencies in toasted samples from Bungoma and Siaya Counties, respectively. Emulsifying capacity varied between 80.85%-82.53%, while emulsifying stability ranged from 80.85%-81.33%. These findings show that the edible Scarabaeus satyrus can provide unsaturated fatty acids and can be a good ingredient in foods as an alternative to conventional cuisines