Waste Orange Peels as a Feed Additive for the Enhancement of the Nutritional Value of Tenebrio molitor

Abstract

Lately, additional attention is being placed on edible insects, since they constitute an excellent, cost-efficient source of proteins with a low ecological footprint. Tenebrio molitor was the first insect that was considered edible by EFSA in 2021. This species can replace conventional protein sources and thus, it has the potential to be used in many different food products. In the present study, a food by-product that is commonly produced (i.e., albedo orange peel waste) was used as a feed additive for T. molitor larvae, in an effort to further improve the circular economy and enhance the nutritional value of the insects. To this end, bran, which is commonly used as feed for T. molitor larvae, was fortified with the albedo orange peel waste (up to 25% w/w). Larval performance, in terms of larval survival and growth, as well as the larval nutritional value, i.e., the content of protein, fat, carbohydrates, ash, carotenoids, vitamins A and C, and polyphenols, was evaluated. Based on the results, the increase in the percentage of orange peel albedos in T. molitor feed resulted in a subsequent increase in the content of larvae in carotenoids and vitamin A up to 198%, in vitamin C up to 46%, and an increase in the protein and ash content up to 32% and 26.5%, respectively. Therefore, the use of albedo orange peel waste for feeding of T. molitor larvae is highly recommended, since it results in larvae with enhanced nutritional value and at the same time, the utilization of this feeding substrate further lowers the cost of insect farming.

Enhancing the Nutritional Profile of Tenebrio molitor Using the Leaves of Moringa oleifera

“…To extract proteins from each sample, 10 mL of distilled water at pH 12, in order to be secured alkaline environment (adjusted with NaOH—1M), was mixed with 1 g of the sample [ 20 ]. The extraction took place at room temperature for 60 min at 500 rpm and upon completion, the mixture was centrifuged for 5 min at 4500 rpm and the supernatant was retracted and transferred to another vial.…”

Nutritional Quality and Antioxidant Properties of Brown and Black Lentil Sprouts

“…The Bradford assay was used to determine the protein content of the samples, according to our previous study [25]. The proteins were extracted by adding 10 mL of distilled water to 1 g of the sample and stirring the mixture at 500 rpm for 1 h at room temperature.…”

“…The phenol/sulfuric acid assay was employed to determine the carbohydrate content of the samples [25]. To extract the carbohydrates, 1 g of the sample was mixed with 10 mL of distilled water and stirred at 500 rpm for 1 h at 50 • C. The mixture was then centrifuged at 3600× g for 5 min at room temperature, and the resulting supernatant was collected.…”

“…The estimation of carotenoid content was carried out using a previously reported method [25]. The extraction step involved adding 10 mL of ethanol to 1 g of each sample and stirring for 30 min at 300 rpm at room temperature.…”

“…To determine the vitamin C content, a modified chromatometric assay was employed [25]. Initially, 5 g of ground LS sample was placed in a beaker, and 27 mL of distilled water:methanol mixture (60:40, v/v) and 3 mL of 10% w/v trichloroacetic acid solution were added sequentially.…”