FROM LOCAL PROTEIN TO NUTRITIOUS FOODS: PROCESSING EFFECTS ON THE NUTRITIONAL AND PHYSICOCHEMICAL CHARACTERISTICS OF SAGO GRUBS

Abstract Sago worms represent an underutilized local protein resource with considerable potential for the development of nutrient-rich and sustainable food products to support Indonesia’s Free Nutritious Meal Program. This study evaluated the influence of different thermal processing methods on the nutritional composition, physicochemical characteristics, fatty acid and amino acid profiles, functional groups, and microstructural properties of sago worms. Samples were prepared as fresh sago worms (SG), air-fried samples (AF; 100 °C for 15 min), and oven-dried samples (OV; 60 °C for 6 h), followed by characterization using proximate analysis, GC–MS, HPLC, FTIR, and SEM. Both thermal treatments substantially decreased moisture content from 67.23% in SG to 13.51% in AF and 12.57% in OV, thereby concentrating protein, fat, and energy. The AF treatment yielded the highest protein content (21.85%), while OV exhibited the greatest fat content (57.60%) and energy value (629.82 kcal/100 g). Oleic acid (omega-9) emerged as a major fatty acid following processing, accounting for approximately 23% in AF and 26% in OV. Glutamic acid was the predominant amino acid across the samples, although thermal treatment modified the relative abundance of several other amino acids. FTIR analysis confirmed that the principal functional groups were largely retained after processing, despite variations in spectral intensity associated with thermal exposure. SEM observations further demonstrated distinct structural modifications, with the porous matrix of fresh samples becoming more compact after air frying, whereas oven drying produced an intermediate microstructure. Overall, these results indicate that controlled thermal processing can enhance the nutrient density and modify the structural characteristics of sago worms, supporting their potential use as a locally sourced protein ingredient for sustainable and nutritious food development.