Freeze drying of edible insects and derived protein products: A review

Sustainable protein sources are crucial for food security, especially to meet the growing population food demand by using fewer resources during production. Recent studies have reported benefits of edible insects in terms of high nutritional content (protein, vitamins and minerals), reduced waste generation and efficient resource use (water, land and feed) with low carbon footprint. There are over 2100 species of edible insects that can be consumed but the habit of insect eating (entomophagy) is still not popular even today. Processing of edible insects is usually conducted through frying or drying and subsequent utilization or consumption can be in the forms of whole insects, insect flour and extracted protein powder which can be incorporated into various food products such as breads, biscuits, noodles, meat patties, beverages, snack bars and so on. In order to preserve the nutritional content of edible insects, processing method using freeze drying is a popular option as compared to conventional hot air drying. However, freeze drying alone has inherent disadvantages such as long drying duration and the high equipment and operational cost. Based on SWOT analysis, hybridization of freeze drying with other techniques (e.g. microwave or infrared) are recommended to improve product quality, energy consumption and drying efficiency. However, more detailed studies need to be conducted especially to evaluate the techno-economic aspects for industrial drying operation. Misconceptions about the safety of edible insects remain a major barrier to consumer acceptance and another critical challenge is allergenicity. Therefore, a more rigorous evaluation of the allergens is needed to assess the risks and to provide a more comprehensive labeling. Future efforts should focus on enhancing regulatory frameworks that govern production and consumption of edible insects as well as educational outreach highlighting health, safety and environmental benefits to build consumer confidence.