Postharvest processes of edible insects in Africa: A review of processing methods, and the implications for nutrition, safety and new products development

Abstract

In many African cultures, insects are part of the diet of humans and domesticated animals. Compared to conventional food and feed sources, insects have been associated with a low ecological foot print because fewer natural resources are required for their production. To this end, the Food and Agriculture Organization of the United Nations recognized the role that edible insects can play in improving global food and nutrition security; processing technologies, as well as packaging and storage techniques that improve shelf-life were identified as being crucial. However, knowledge of these aspects in light of nutritional value, safety, and functionality is fragmentary and needs to be consolidated. This review attempts to contribute to this effort by evaluating the available evidence on postharvest processes for edible insects in Africa, with the aim of identifying areas that need research impetus. It further draws attention to potential postharvest technology options for overcoming hurdles associated with utilization of insects for food and feed. A greater research thrust is needed in processing and this can build on traditional knowledge. The focus should be to establish optimal techniques that improve presentation, quality and safety of products, and open possibilities to diversify use of edible insects for other benefits.

Edible Insects Processing: Traditional and Innovative Technologies

“…The highest diversity is in the orders Lepidoptera, Orthoptera , and Coleoptera (Kelemu et al., ). Most edible insects are harvested from the wild (Mutungi et al., ). They are cleaned (with the removal, in some cases, of certain parts, such as wings and legs), and then roasted or boiled.…”

Protein Solubilization

“…Up to 2000 edible insect species have been reported (Rumpold & Schluter, ; Sun‐Waterhouse et al, ) and are consumed globally, particularly in Asia, Africa, Oceania, Latin America, and the Middle East (Feng et al, ; Kelemu et al, ). Notable advantages of insects over traditional animal sources include (1) ability to convert ingested organic matter into high‐quality protein more effectively (Gahukar, ; Mutungi et al, ) and (2) less natural resources required for production compared to conventional food source production (Mutungi et al, ). Available data on reported insect foods indicate that the most widely consumed insect sources are butterflies, moths, beetles, grubs, crickets, grasshoppers, and locusts with protein content ranging from 23% to 25% on a fresh weight basis (Nowak et al, ).…”

Impact of heat processing on the nutritional content of Gryllus bimaculatus (black cricket)

“…To date, only a limited number of studies have examined the impact of processing temperature on the nutritional profile of edible insects, and previous studies have done this predominantly within the context of how the insects are traditionally prepared rather than systematically (Mutungi et al . ). This study examined the impact of various drying temperatures on the nutritional content of black crickets and found that while some effect is seen on protein and micronutrient content, the most marked change is seen in the fatty acid profile, with black crickets dried at higher temperatures showing lower levels of polyunsaturated fatty acids (PUFAs).…”

“…; Mutungi et al . ), although neither of these studies compared a distinct set of temperatures but rather distinct processing methods such as boiling versus frying. The finding that micronutrients such as iron, potassium and zinc in black crickets are largely not affected by processing temperature is important as it suggests that insects can be processed into foods such as buns, biscuits, flour and porridge without reducing their micronutrient value.…”

“…Second, there is some evidence to suggest the gut contents of insects have an impact on their nutrient content (Mutungi et al . ) and this was not controlled for in the study. While the crickets had all been given free access to food prior to being dispatched, it is possible that some of the crickets had fuller guts than others.…”