Insects in your soup? Research shows growing interest in eco-friendly, protein-rich food sources

By Neha MathurDec 12 2023Reviewed by Lily Ramsey, LLM

In a recent study published in the Journal Nutrients, researchers assessed the acceptance level of various soups with insect flour versus a control sample among 104 subjects, including 55 seniors and 49 young adults in Poland. 

Study: The Acceptance of Cream Soups with the Addition of Edible Insects (Mealworm, T. molitor; House Cricket, A. domesticus; Buffalo Worm, A. diaperinus; Grasshopper, R. differens) among Young People and Seniors in Poland. Image Credit: nicemyphoto/Shutterstock.com

Background

Insects represent a promising food source due to their high nutritional value, taste, inexpensive and efficient production, and minimal environmental impact.

They are more protein-rich than traditional meat products and contain many essential vitamins and minerals, especially iron and zinc. 

Given the growing awareness of a sustainable food chain and ecology, they may be introduced into the diets of Europeans and Americans that, so far, have remained challenging.

Further expansion of the insect foods market would require more consistent legal regulations, ensuring production safety, and a plethora of products meeting individual consumer requirements. However, the most important is spreading awareness of the benefits of insect consumption.

Amid increasing demand for diverse foods, as per estimates, the market share of aquafeed, including edible insects, will surge from 17%-40%.

Edible insects vary substantially in taste, shape, use, maturity stage, and serving form, and even their nutritional value varies with species, breeding conditions, and processing methods. 

In the Western world, insects are not as widely accepted as food due to a lack of taste and high neophobia levels.

However, acting for higher goals, such as planet health, might provide the requisite impetus to add insects to people's daily diets in these countries. Yet, their origin, safety, durability, and serving method remain vital.

The most accepted form of insect consumption is the powder form. Thus, partly crushed insects or insect flour are added to many commonly eaten food products, such as cereals (bread, biscuits), sweets, etc. Similarly, adding whole insects, either as larvae or imago, to soups can be interesting.

Studies on using insects in soups have been conducted in Africa and Asia but on a small scale. However, the number of such studies has remained small, and these studies used youth as their target population, as the dietary patterns of older people are considered unchangeable.

About the study

In the present study, researchers investigated the acceptance levels of cream-type soups comprising tomatoes or white vegetables and 20% flour from four insect species in groups of young adults and seniors in Poland. 

These were mealworm (Tenebrio molitor), buffalo worm (Alphitobius diaperinus), house cricket (Acheta domesticus), and grasshopper (Ruspolia differens).

They prepared the tomato and the white vegetable soups and blended them into a smooth cream. Next, they calculated the caloric value per 100 mL of each soup. The base dishes, tomato and white vegetable cream soup, with caloric values of 85 and 114 kcal/100 mL, served as controls.

Per previous studies, the addition of >20% insect flour altered the taste and texture, leading to consumer rejection, while a lower content was undetectable.

Thus, in the next phase, the team added 20% flour from four edible insect species relative to the control sample's dry weight, which served as the study's test samples. 

Finally, the researchers tested ten soups: five tomato and five white vegetable. These were served just after preparation, with each serving containing 50mL of soup. Specifically, the team analyzed their ash, protein, and water content and the total, insoluble, and soluble dietary fiber content.

In consumer acceptance analysis, healthy, voluntary evaluators who did not have food neophobia used rating cards and an unstructured scale to evaluate the appearance, taste, smell, texture, and acceptance, i.e., all sensory attributes of soups. 

In statistical analysis, the PQStat Software checked the normality of data distribution and applied non-parametric tests when necessary.

A mathematical model then determined the influence coefficients of aroma, appearance, taste, and texture on the acceptance of edible insects.

Results

Two age-extreme tester groups participated in this study: 55 seniors over 60 and 49 young adults, of which 58.8% constituted the neutral group on the neophobia scale (FNS), while 21.5% were neophiles. The proportion of neutral participants was higher among seniors than young adults (62.3% vs. 54.3%).

Contrary to expectations, even older individuals displayed great willingness to participate in this study investigating factors influencing the consumers in Poland (in Europe) to consume insects.

There was no statistically marked association across age groups studied, albeit they rated all four sensory attributes of the insect-based soups lower, including controls. In the future, it will allow for the expansion of the target consumer group for insects. 

Further, the study results suggested that the control samples without insect flour received the highest ratings in both age groups for the overall acceptability and individual descriptors.

Thus, these were rated significantly higher than the cream of white vegetable soup in all test samples based on tomato soup (9 vs. 8.5 points on a 10-point scale). 

Many studies have indicated that mealworms typically achieve the highest acceptance, given their slightly nutty taste.

In this study, accordingly, tomato soup with the addition of mealworm flour attained the highest overall acceptability. 

Soups with buffalo worm attained the second-highest acceptability rating, while both soups with grasshopper received the lowest rating in both groups of participants.

Tomato-based soups had a more pronounced taste and intense color, which helped hide the peculiar taste and appearance of the insect additive. Even in previous studies on other food products, the color and rheological characteristics were the key determinants of sensory attributes.

The appearance ratings of soups with insect flour were consistently lower than those of soup preparations with no insects. Among those, the appearance rating was lower even for the tomato soup with grasshoppers.

In aroma evaluation, all soups with added insects showed a decline in acceptance, attaining statistical significance at a p-value of 0.00005 in the Wilcoxon T-statistic test.

The addition of buffalo and mealworms in the tomato soup significantly lowered their taste rating, with the rating being the lowest soups with a grasshopper (average rating of 4.22).

The white vegetable soups with grasshopper attained a taste rating of less than four, disqualifying this soup variant on taste parameters.

The consistency of soups is another key parameter for cream soups. In this study, creams based on insects in the imago form were rated much lower than test samples with mealworms and buffalo worms (added as larvae).

Multiple regression analysis identified the taste and texture of soups with a 20% insect flour additive as the key determinants shaping their overall acceptability, implying palatability is the most important criterion to meet when proposing insect-based food to consumers. 

Indeed, designing food with high sensory qualities that even the most conservative consumers will accept requires more extensive sensory studies on various insect-based food products in different forms.

Conclusions

Neophobia towards new foods and general negative perceptions of products based on insects have hindered the entry of products containing them as ingredients in Europe and other developed countries.

This study demonstrated the importance of the base product and the recipe (in this case, soup) in a product containing insects as a hidden ingredient.

Among the four insect species studied, tomato soup and cream of white vegetables with mealworms (T. molitor) achieved the highest level of acceptance, and soups with grasshoppers (R. differens) received the lowest ratings. 

Future research should focus on developing novel, attractive food products that incorporate edible insects.