Tenebrio molitor Mealworm

Abstract

Mealworms are the larvae of two species of darkling beetles of the Tenebrionidae family: the yellow mealworm beetle (Tenebrio molitor Linnaeus), and the smaller and less common dark or mini mealworm beetle (Tenebrio obscurus Fabricius). Larvae typically measure about 2.5 cm or more, whereas adults are generally between 1.25 and 1.8 cm in length. Mealworms are typically fed live, but canned and dried larvae are commercially available. Minimum protein solubility (29.6%) was at pH 4–6 and maximum (68.6%) at pH 11. Protein extraction at 0.1 M NaCl, pH 10 gave a recovery of 100%. The nutritional value of live mealworm is composed of 20% protein, 13% fat, 2% fiber, and 62% moisture, while the dried mealworm’s nutritional value is composed of 53% protein, 28% fat, 6% fiber, and 5% moisture. The main fatty acids of the obtained biodiesel were linolenic acid (19.7%), palmitic acid (17.6%), linoleic acid (16.3%), and stearic acid (11.4%). The mealworm grease has an acid value of 7.6 (mg KOH/g), iodine value of 96 (g I/100 g), and saponification value of 162 (mg KOH/g) with low peroxide value of 0.27 (mEq./kg). The gross energy of the mealworm was 206 kcal/100 g fresh weight, depending on the insect’s diet.