Earth Worming—An Evaluation of Earthworm (Eisenia andrei) as an Alternative Food Source

Abstract

Aside from their bioremediation roles, little is known about the food and feed value of earthworms. In this study, a comprehensive evaluation of the nutritional composition (proximate analysis and profiles of fatty acids and minerals) and techno-functional properties (foaming and emulsion stability and capacity) of earthworm (Eisenia andrei, sourced in New Zealand) powder (EAP) were investigated. Lipid nutritional indices, ω6/ω3, atherogenicity index, thrombogenicity index, hypocholesterolemic/hypercholesterolemic acid ratio, and health-promoting index of EAP lipids are also reported. The protein, fat, and carbohydrate contents of EAP were found to be 53.75%, 19.30%, and 23.26% DW, respectively. The mineral profile obtained for the EAP consisted of 11 essential minerals, 23 non-essential minerals, and 4 heavy metals. The most abundant essential minerals were potassium (8220 mg·kg−1 DW), phosphorus (8220 mg·kg−1 DW), magnesium (744.7 mg·kg−1 DW), calcium (2396.7 mg·kg−1 DW), iron (244.7 mg·kg−1 DW), and manganese (25.6 mg·kg−1 DW). Toxic metals such as vanadium (0.2 mg·kg−1 DW), lead (0.2 mg·kg−1 DW), cadmium (2.2 mg·kg−1 DW), and arsenic (2.3 mg·kg−1 DW) were found in EAP, which pose safety considerations. Lauric acid (20.3% FA), myristoleic acid (11.20% FA), and linoleic acid (7.96% FA) were the most abundant saturated, monounsaturated, and polyunsaturated fatty acids, respectively. The lipid nutritional indices, such as IT and ω-6/ω-3, of E. andrei were within limits considered to enhance human health. A protein extract derived from EAP (EAPPE), obtained by alkaline solubilisation and pH precipitation, exhibited an isoelectric pH of ~5. The total essential amino acid content and essential amino acid index of EAPPE were 373.3 mg·g−1 and 1.36 mg·g−1 protein, respectively. Techno-functional analysis of EAPPE indicated a high foaming capacity (83.3%) and emulsion stability (88.8% after 60 min). Heat coagulation of EAPPE was greater at pH 7.0 (12.6%) compared with pH 5.0 (4.83%), corroborating the pH-solubility profile and relatively high surface hydrophobicity (1061.0). These findings demonstrate the potential of EAP and EAPPE as nutrient-rich and functional ingredients suitable as alternative food and feed material. The presence of heavy metals, however, should be carefully considered.

Earthworms: Anti-Aging Skin Care Miracle

“…Rigorous scientific studies, including clinical trials and laboratory analyses, are being conducted to understand the mechanisms behind earthworm-derived ingredients and their effects on the skin. This research-driven approach ensures that any products emerging from these efforts are not only backed by evidence but also adhere to the highest safety and quality standards (Kavle et al, 2023).…”

Can foraging for earthworms significantly reduce global famine in a catastrophe?

“…Considering the three dry matter content values, a mean of 17% suggests there are 900 million tonnes of earthworm dry matter available globally. The nutritional value of earthworms is described for earthworm meal with dry matter crude protein content in the range of 53.8% to 72.9% [11,12,23,30] depending on the species and the method of preparing earthworms for consumption. Taking the mean from several nutritional values for whole earthworm dry matter of 60.7% estimates the global earthworm nutritional protein resource is 540 million tonnes.…”

“…Taking the mean from several nutritional values for whole earthworm dry matter of 60.7% estimates the global earthworm nutritional protein resource is 540 million tonnes. The energy content of earthworms is less widely reported, but a mean estimate of 4.068 kcal•g −1 of dry matter can be derived from Sun et al's value for partially dried Eisenia fetida worm meal [23] and Kavle et al's [11] value for Eisenia andrei. The total nutritional energy resource is 3.65 × 10 15 kcal equivalent to 910 million tonnes of dry carbohydrate.…”

“…The total nutritional energy resource is 3.65 × 10 15 kcal equivalent to 910 million tonnes of dry carbohydrate. Epigeic earthworms have mean dry matter fat content of 13.7% as derived from the literature [11,23], suggesting the total dietary fat resource of the earthworm population is 122 million tonnes. Based on World Health Organisation requirements for daily fat intake to comprise at least 15% of daily caloric intake [31,32], earthworms could represent a significant nutritional resource.…”

“…Across the globe, earthworms have provided a source of nutrition for people in many societies [9][10][11][12] as well as a safe feed ingredient for livestock [13][14][15]. There are also reported instances of people earning a living from collecting and selling wild earthworms [16].…”