foods Review Quality Aspects of Insects as Food—Nutritional, Sensory, and Related Concepts Mohammed Elhassan 1,*, Karin Wendin 2,3 , Viktoria Olsson 2 and Maud Langton 1 1 Department of Molecular Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden; [email protected] 2 Department of Food and Meal Science, Kristianstad University, SE-291 88 Kristianstad, Sweden; [email protected] (K.W.); [email protected] (V.O.) 3 Department of Food Science, University of Copenhagen, Bülowsvej 17, DK-1870 Frederiksberg C, Denmark * Correspondence: [email protected] Received: 6 February 2019; Accepted: 7 March 2019; Published: 12 March 2019 Abstract: In the search for another appealing source of future food to cover the increasing need for nutrients of a growing global population, this study reviewed the potential of insects as human food. Most previous reviews have dealt with insects as a group, making it difficult to evaluate each individual insect species as food because of the generalized data. This study assessed some common edible insects, but concentrated on mealworms. Insects, especially mealworms, have a similar or higher nutritional value than many conventional food sources. For example, the protein content of mealworm larvae is reported to be almost 50% of dry weight, while the fat content is about 30% of larval dry weight. Mealworms can be cooked by different methods, such as hot air drying, oven broiling, roasting, pan frying, deep frying, boiling, steaming, and microwaving. Oven broiling in particular gives a desirable aroma of steamed corn for consumers. Changes in the flavor, taste, and texture of mealworm products during storage have not been studied, but must be determined before mealworms can be used as a commercial food source. Factors controlling the shelf-life of mealworms, such as their packaging and storage, should be identified and considered with respect to the feasibility of using mealworms on a commercial scale. Keywords: cricket; grasshopper; neophobia; protein; nutrition 1. Introduction The global population is steadily increasing [1,2], making food security a crucial issue world-wide. Both the quantity and quality of food supply are of interest in the context of food security. All major nutrients are important, but protein is one of the main nutrients required by humans, and protein deficiency leads to severe illness. Protein from animal sources may be especially valuable, as it contains essential amino acids that are not found in many plant proteins. However, protein from animal sources is not always affordable for a large share of the global population [3]. Moreover, devastating wars are still occurring in various parts of the world, resulting in millions of people, especially innocent civilians, being displaced and often suffering from malnutrition due to a lack of food. During or immediately after wars, people need a fast source of protein, but conventional sources of protein (animals and plants) take a long time to become available. This means there is a need for fast protein sources that are nutritionally similar to protein from conventional sources. During the First World War, Germany used single-cell protein as the source of protein in animal feed, in order to meet human protein requirements [4]. However, direct consumption and excess consumption of single-cell protein by humans have negative effects on health, since it contains nucleic acids which cause the precipitation of uric acid in the human body, leading to gout and the formation of kidney stones. Another issue Foods 2019, 8, 95; doi:10.3390/foods8030095 www.mdpi.com/journal/foods Foods 2019, 8, 95 2 of 14 with the production of protein from animal sources is that it requires advanced resources, in many cases making it unsustainable for the environment [5]. Moreover, animal rearing for food is controlled by strict ethical rules and regulations, which can complicate the process. For the above reasons, an alternative source of protein is needed to assist in assuring food security for the increasing global population. One such source could be insects. The aim of this literature review was to examine the use of insects as a sensory appealing food and to identify knowledge gaps in this area (Figure1). Although it is commonly claimed that insects are a non-traditional food, more than two billion people in 113 countries generally eat insects directly or use them as food ingredients [6–8]. It is estimated that there are up to 1900–2000 species of edible insect [6,9]. The tradition of eating insects is very old, e.g., there is evidence that insects were eaten during pre-historic times, forming an important source of protein [10,11]. FoodsFoods2019 ,20198, 95, 8, x FOR PEER REVIEW 3 of 153 of 14 Insects as human food Problem statement Why insects Foods made from Packaging and Insects toxicity insects storage Securing food for High nutritional Indigenous toxins increasing Effect of packaging value population in shelf life Transmitted toxins fast source of High feed Effect of storage and diseases protein in wars and conversion ratio conditions in shelf natural crisis life In which forms are eaten Effects of processing Sensory tests methods in the quality conclusion FigureFigure 1. 1.Flowchart Flowchart ofof insectsinsects as human food food literature literature review review.. Foods 2019, 8, 95 4 of 14 2. Nutritional Value of Insects Insects have been proven to have high nutritional value, especially the protein fraction in terms of adequate amino acid composition [12]. The amino acid composition in the larvae of yellow mealworm Foods 2019, 8, x FOR PEER REVIEW 4 of 16 (Tenebrio molitor) is particularly favorable [13]. A study investigating four insects commonly eaten in Nigeria2. (African Nutritional palm Value weevil, of Insects coconut palm rhinoceros beetle, caterpillar, and termite) found that the essential aminoInsects acids have lacking been proven in cereal to have protein, high nutritional i.e., lysine value, and especially methionine, the protein were fraction present in terms in relatively high amountsof adequate in these amino insects acid com [14position]. The overall[12]. 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