Using Edible Insects in the Production of Cookies, Biscuits, and Crackers: A Review ^†

Abstract

The world’s population is ever-increasing and thus food security is becoming a big problem. To meet protein demand, edible insects could be a sustainable, eco-friendly, economical, and alternative source. However, consumers have some concerns about the sensorial properties of edible insect-based foods. To make them invisible and more familiar to consumers, powder of edible insects could be used together with flours in most commonly consumed bakery products, particularly bread, followed by biscuits, cookies, and crackers. Moreover, the rearing and processing conditions should be enhanced, a marketing strategy should be developed, and education about the health and environmental benefits should be given.

1. Introduction

Eleven percent of the world’s population are, nearly two billion people are influ enced by nutrient deficiencies, and the world’s population is ever-increasing and predicted to reach 9.7 billion by 2050 [1]. Therefore, food security is becoming a major problem and thus sufficient nutrition should be provided immediately, especially in the countries that are in poverty. In this regard, edible insects could be a promising source to meet the demand, particularly as an alternative resource of protein [2]. The main reasons behind using edible insects are that they have high nutritional value, especially in terms of the high quality and amount of protein, lipids, vitamins, and mineral composition, together with the issues related to environment and sustainability, and also some economic factors. In this regard, edible insects also reduce water pollution, greenhouse gas emission, and pesticide usage. Moreover, they have a short reproduction cycle, a high growth rate, a high feed conversion ratio, and widespread distribution when compared with livestock [3]. Therefore, since 2010, the FAO has been evaluating the possibility and potential of utilizing edible insects for feed and food to meet food security [4]. However, the consumption of edible insects as food, i.e., entomophagy, emerged approximately 7000 years ago [5]. It is known that there are more than 2000 species of edible insects in the world [6], and the most consumed ones are ants, bees, crickets, and flies. Most recently, dried Tenebrio molitor larva (yellow mealworm) has been authorised the placing on the market as a novel food under Regulation (EU) 2015/2283 of the European Parliament [7]. As a result, the market of edible insect-based food products is going to grow quickly and gain more space in the markets, and thus is predicted to produce reach nearly 260,000 tons by 2030, according to the International Platform of Insects for Food and Feed [8].

2. Effects of Using Edible Insects on the Nutritional Values and Technological Properties of Cookies, Biscuits, and Crackers

Bakery products are more promising food products to enrich with powder forms of edible insects that could develop not only their nutritional value but also influence both the technological and sensory properties of the end-products [9]. However, there is limited research in the literature regarding cookies, biscuits, and crackers enriched with edible insects, as summarized in

Table 1. The effects of edible insects on a number of technological and sensorial properties of some bakery products.

Bakery Product	Edible Insect	Usage Ratio	Results	References
Biscuit	Mulberry silkworm pupae (Bombyx mori), Locust	15% a	Weight ↓, width ↑: silkworm; ↔: locust, thickness ↑, spread ratio ↓, sensory properties ↔ (except aroma)	[17]
Biscuit	Termite (Macrotermes subhyalinus)	5, 10, 15, 20, and 25% b	Weight ↓, diameter ↑ (except 5% inclusion), thickness ↓, spread ratio ↑, specific volume ↔, sensory properties ↔	[13]
Biscuit	Termite (Macrotermes nigeriensis)	5, 10, 15, and 20% b	Weight ↑; diameter ↑ (except 5% inclusion); spread ratio ↑; breaking strength ↓; sensory properties: taste ↓, aroma ↔, texture ↔, overall acceptability ↓ (except 5% inclusion)	[15]
Shortcake biscuit	Mealworm (Tenebrio molitor)	1:9, 1:14, 1:19 c	Diameter ↔, thickness ↔ (except 1:9 inclusion), spread ratio ↔ (except 1:9 inclusion), L* ↓, a* ↑, b*↓, Browning index ↑	[18]
Biscuit	Cricket (Acheta domesticus)	5, 10, and 15% b	Color: L* ↓, a* ↑, b* ↓; texture: hardness ↔; sensory properties: odor ↔, flavor ↓ (except 5% inclusion), color ↓ (except 5% inclusion), texture ↔, overall liking ↓	[9]
Biscuit	Termite (Macrotermes subhyalinus)	5, 10, 15, 20, and 25% b	Weight ↓, diameter ↑, thickness ↓, spread ratio ↑, specific volume ↓, sensory properties: taste ↔ (except 25% inclusion), aroma ↔, color ↓, texture ↔ (except 20 and 25% inclusion), appearance ↔, overall acceptability ↔	[14]
Baby biscuit	Grasshopper (Melanoplus cinereus)	5, 7, and 10% a, b	Sensory properties: taste ↑, aroma ↑, color ↑, texture ↑	[16]
Cookie	Termite (Macrotermes belliscosus)	5, 10, and 15% b	Weight ↓; diameter ↓; thickness ↑ (except 5% inclusion); spread factor ↓; color: L* ↓, a* ↑, b* ↑; texture: hardness ↓, fracturability ↑	[12]
Cracker	Cricket, termites (soldier termite, winged termite)	8% b	Sensory properties: taste ↓, flavor ↓, aroma ↓, color ↓, appearance ↓, overall acceptability ↓	[11]

↓ indicates an increment that is statistically different; ↑ indicates a decrease that is statistically different; ↔ indicates an increment or decrease that is not statistically different. ^a: the concentration in the whole recipe; ^b: the ratio of raw material replacement; ^c: the ratio of the edible insect to raw material (edible insect: flour).

. The commonly used edible insects are crickets [9,10,11], termites [11,12,13,14,15], grasshoppers [16], locusts [10,17], silkworm pupae [17], mealworms [18], and palm weevil larvae [19], which can generally replace raw material in concentrations between 5 and 25% of bakery products, as seen in Table 1. Moreover, termites are the most used by researchers from among these. It has also been revealed that crackers enriched with winged termites are more preferred than those enriched with crickets. Crackers also had the highest values for sensory features, which were not significantly different from those of the control sample. This was attributed to the high fat content, which positively influences the flavor and texture [11].

The protein and fat content increased while the carbohydrate and fiber content decreased in cricket-enriched biscuits when compared with the control sample without the addition of edible insects [9]. A similar pattern, except for fiber content, was observed in baby biscuits containing wood grasshopper flour [16], biscuits fortified with palm weevil larvae [19], and biscuits and cookies including termites [13,15]. The biscuits enriched with silkworm pupae had a higher content of protein and fat, but a slightly lower content of carbohydrate, ash, and fiber than locust-enriched biscuits. Moreover, the pro-vitamin A and vitamin C contents were twice higher in both biscuits made with these edible insects, according to the United States Agency for International Development commodity specifications for high-energy biscuits [17]. The mineral composition was enhanced when using locust [17], termite [13,14], or grasshopper [16] in biscuit formulations. In addition, saturated fats were dominant, and caproic acid together with arachidic acid was the most abundant fatty acid in biscuits enriched with palm weevil larvae. However, lauric acid, myristic acid, and monounsaturated fatty acids were present in trace amounts in both biscuits supplemented with palm weevil larvae at both low and high concentrations [19]. The different drying methods altered the ratio of individual fatty acids [20]. On the other hand, the protein digestibility was higher when compared with the control cookies made with 100% wheat flour, and also increased with increasing concentrations of winged termite in cookie formulations. In addition, the composition of essential amino acids, which was dominated by leucine and lysine, was higher than in the control sample and also generally met the reference values for both children and adults according to the standards of FAO)/WHO, 2007 [12]. However, in vitro protein quality was decreased in baby biscuits including wood grasshoppers compared with the control biscuits without edible insects substituting for flour. This was explained by the high fiber content of the grasshopper and also the Maillard reaction [16]. Moreover, the rapidly digested starch decreased, whereas slowly digested starch content increased, and the in vitro glycemic index did not change significantly in mealworm-enriched shortcake biscuit [18].

Skimmed milk powder was replaced at 15% concentration with two different edible insects (mulberry silkworm pupae and locust). Although no apparent defect was observed in some quality parameters in biscuits such as thickness and spread ratio, the thickness increased whereas the spread ratio decreased statistically significantly in edible insect-based biscuits compared with the control sample containing skimmed milk. Moreover, while the thickness values were higher in biscuits made with locusts, the spread ratio values were higher in biscuits containing silkworm pupae [17]. A similar tendency was observed in cookies enriched with termite at three different concentrations [12]. An adverse effect was observed in biscuits incorporated with termite (Macrotermes subhyalinus) [13,14]. On the other hand, no significant differences were found in diameter in biscuits containing 5% termites [13]. Adding cricket powder into the flour mixture in the biscuit recipe increased values of a* and total titratable acidity, but a decline in the L* and b* values. Moreover, this tendency was increased when the amounts of edible insect increased [9].

The drying parameters and drying methods of edible insects could affect not only the nutritional quality in terms of protein digestibility, fatty acid composition, and solubility of minerals [11], but also the volatile composition and odor characteristics, and thus the sensory properties of the end-products [20]. In this regard, winged termites were oven-dried at three different temperatures (90, 120, and 150 °C) for 10 min to enrich a cracker recipe. According to the results, nutritional value, in terms of protein digestibility and the solubility of iron and zinc decreased, whereas the energy value increased, although the sensory properties were not significantly affected by the drying temperature [11]. On the other hand, two different drying methods (freeze-drying and microwave-drying) were applied to locusts and silkworms to determine the impacts on the volatile profiles and sensory attributes of cookies enriched with edible insects. The microwave-dried insects caused additional emissions of pyrrole and pyrazine, and showed a roasted odor that is typical of the Maillard reaction [20].

3. Effects of Using Edible Insects on the Sensory Properties of Cookies, Biscuits, and Crackers, and Their Consumer Acceptance

The most effective factor in the decision between eating or avoiding insect-containing foods is cultural background [21]. The other drawbacks of edible insect-based food products are based on concerns of health and food safety, but also some organoleptic features such as flavor, aroma, color, and texture [22]. Therefore, there are some strategies, generally based on farming (breeding and diet) and processing methods of edible insects, to enhance the sensorial appeal of edible insects incorporated into food formulations. Moreover, adding edible insect powder together with flour where it is not visible to most consumed and in familiar foods such as bakery products has a great potential to overcome these barriers to increase consumer acceptability. On the other hand, the rearing and processing methods and parameters of edible insects such as defatting, drying, heat treatments, and protein extraction have an impact upon the sensory attributes of the end-products [21]. Microwave-dried and freeze-dried locusts were more preferred by panelists instead of raw insects and oven-dried insects. However, there were no significant differences between the control sample and the cookies enriched with locusts that were exposed to different drying methods. Moreover, caramelized and bready notes were dominant, although the odor intensity varied among different drying methods. In addition, the raw ground form of silkworms had higher overall liking scores than raw locusts. Freeze-dried samples had similar overall liking scores to control cookies without insects. However, cookies including microwave-dried locusts had the strongest aroma intensity with a dominant fishy odor, and thus were the least liked [20]. On the other hand, none of the sensorial attributes (taste, color, appearance, crispiness, and overall acceptability) except aroma were affected by the replacement of skimmed milk powder with edible insect such as locusts and silkworm pupae in a biscuit recipe [17]. Similar results were obtained for texture and crispiness in biscuits including termites [13]. In another study, the odor and texture properties were not affected by the inclusion of crickets in the biscuit recipe. However, the values of color, flavor, and overall liking were lower than oat flour-based control biscuits, which were more obvious in biscuits containing more than 5% cricket. Therefore, the biscuits with high amounts of edible insects were rejected by panelists, although the biscuits enriched with 10% and 15% cricket could be labeled as protein sources according to European Union’s Regulation No. 1924/2006. In addition, while cheesy and fatty flavors had a positive impact on overall liking, burnt flavor and color had a significantly negative effect on overall liking, according to results of check-all-that-apply (CATA) questions [9].

To promote the intake of protein and iron to decrease the incidence of malnutrition and anemia in pregnant women, biscuits were enriched with palm weevil larvae. Women were willing to buy these biscuits in the markets, and these biscuits were acceptable in terms of sweetness, aroma, color, and texture, according to the results of a sensory evaluation [19]. In another study, the acceptability and sensory attributes (the liking and intensity of hardness, crunchiness, bitterness, flavor strength, etc.) of chocolate chip cookies in which wheat flour was replaced by cricket flour at two different concentrations (15 and 30%) were evaluated by 200 consumers from each of three different countries (USA, Spain, and Mexico) using a nine-point hedonic scale. The cookies enriched with insects at 30%, were as acceptable as the control sample for Mexican consumers because of the respondents being more familiar with insect-based food products in those countries [23]. To determine the most consumed and/or preferred edible insect out of four different edible insects (termites, crickets, grasshoppers, and palm weevil), a survey providing a pictorial representation for ranking was sent to 79 consumers from a rural community in Nigeria. According to the results, termite was the most liked one, because of it being cheap and available locally, and needing less time for cooking, together with better taste. On the other hand, cricket was the least preferred insect among them as it was expensive and took more time for cooking. Later, termites were used with sorghum flour at the ratio of 1:3 as a composite flour to substitute for wheat flour at three different concentrations (20, 40, and 60%) for biscuit production. To investigate the acceptability of termites as an ingredient of biscuits, sensorial attributes such as taste, aroma, color, texture, and overall acceptability were assessed using a five-point facial hedonic scale by 84 consumers who had no allergies and who ate and/or were willing to try the biscuits and insects. Although biscuits supplemented with insects had an uneven surface, the biscuits enriched with 5% termite had better results in all attributes than the control sample made with 100% wheat flour. Moreover, the texture parameters were not affected by an increase in the insect concentration, whereas an intense brown color was monitored, which led to the biscuits with the highest amount of added insect being the least acceptable by consumers [24]. In another study, a 4-week-long parallel randomized study was conducted to assess the acceptability and suitability of biscuits containing edible insects for school feeding programs in Kenya. This is because Kenyan children are at risk of undernourishment, and milk powder is expensive and is not produced locally. Therefore, house cricket at a proportion of 10% was used in the biscuit formulation instead of milk powder. To determine acceptability, the weight of eaten biscuits was collected daily and the sensorial attributes (looks, color, smell, taste, texture, and overall) were evaluated once a week with a five-point facial hedonic scale by 54 Kenyan children aged between 5–10. The score of most sensorial properties, except color and taste, were lower than those of the control sample but were above the average score, which was defined as 2.5, although the color of biscuits containing insects was darker and their size was relatively bigger than that of milk biscuits. Moreover, the consumption of biscuits was determined to be about 97% and 94% for insect-based and milk powder-based biscuits, respectively [25].

4. Conclusions

Edible insects have gained a place in baked goods such as like biscuits, cookies, and crackers, followed by bread. The edible insects are mainly used in the recipes of those baked goods for generally replacing different kinds of flours, at a range of 5% to 25% in general. Among the edible insects, termites are the most used and preferred ones. Although the results of some sensory studies are promising, which indicated no significant differences from the control samples, there are still limitations for consumer acceptability, although edible insects have high nutritional value and higher digestibility than plant-based proteins. The limitations are much more related to the sensorial attributes, together with neophobia or concerns related to health. However, edible insects could still be a good alternative and a valuable resource to enrich bakery products by increasing the nutritional value and meeting the protein shortage. Therefore, further studies should mainly focus on making edible insect-enriched food products more appealing to consumers by modifying food formulations or masking some off-flavors, and should also determine the optimum conditions for pre- (rearing) and post-processing edible insects (drying, defatting, etc.).