Sun drying and roasting mulberry silkworm pupae with salt improves dehydration efficiency, microbiological safety, fatty acid and amino acid profile, and protein digestibility and quality

Abstract

Mulberry silkworm pupae (Bombyx mori), a popular but highly perishable edible insect, were processed by sun-drying (32–42 °C, 16 h during the day) and roasting (200 °C, 35 min), without and with salt seasoning (1% and 3% w/w). The effects of these processes on the physicochemical, microbiological, and nutritional qualities of the pupae were investigated. A processed sample, selected for its superior overall nutritional profile, was incorporated into 3 food dishes, and their nutritive values were compared to traditional dishes without pupae. The results showed that sun-drying and roasting could enhance the stability and microbiological safety of the pupae by significantly reducing moisture content (~ 15 to 29-fold) and a<inf>w</inf> (~ 3 to 6-fold), with salt enhancing dehydration during processing. The sun-dried and roasted samples processed with 1% (w/w) salt demonstrated improved fatty acid and amino acid profiles compared to the unprocessed material. The SSP1 sample, in particular, demonstrated superior lipid and protein quality, making it a promising nutrient-dense ingredient for food fortification. Foods fortified with SSP1 showed a significant increase in energy (2–6%) and higher levels of protein, fat, and dietary fiber (up to 2.8-fold, 1.1-fold, and 1.3-fold, respectively) compared to traditional recipes without insect incorporation. These results emphasize the effectiveness of sun-drying and roasting in processing mulberry silkworm pupae, offering practical solutions for post-harvest management, food security, and sustainability through insect protein, especially for communities with limited access to diverse protein sources. Furthermore, incorporating mulberry silkworm pupae into food formulations could promote insect consumption among populations unfamiliar with entomophagy.