Writing in Food Science and Technology, researchers from the Technological Institute of Tuxtepec in Mexico and New Mexico State University developed extruded snacks with grasshopper meal to establish what impact, if any, use of the protein had on the physicochemical properties of the product.
The researchers chose to work with corn because it represented a “basic component of human nutrition mainly in Latin America”, they said, and because Mexico had the highest per capita global consumption of the cereal. They also decided to work with extrusion because it “was one of the most important technologies” that had shown “great potential” in the development of new products.
“In recent years, consumer demand for nutritious extruded snacks has grown; therefore, it is necessary to generate appetizing products that take advantage of the nutritional benefits of the cereals and promote the substitution of 'junk foods' for healthy options,” they wrote.
Edible insect sources
Whilst a range of ingredients had previously been incorporated into snacks, including vegetables, fruits and fishmeal, the researchers said use of edible insect sources to increase protein in extruded foods had rarely been investigated.
Grasshoppers – an “unconventional protein source” – they said, were high in protein (52.74g per 100g once ground into meal), high in vitamins A and B, as well as zinc, magnesium and calcium, and were therefore a nutritionally interesting addition to snacks.
The researchers used the grasshopper species Sphenarium purpurascens Charpentier because it was Mexico's most abundant, found widely across the country from the center to the south and west.
The grasshoppers were dried at 65°C for 24 hours before being ground to a mesh size of 0.50mm to include into the extruded corn snacks.
During the study, the researchers analyzed what impact extrusion temperature, feed moisture content and grasshopper meal proportion had on the final snacks, looking at index of expansion, bulk density, hardness, total color difference, and sensory evaluation.
“The extrusion conditions (feed moisture content and temperature) and the formulation (i.e grasshopper meal in the nixtamalized maize flour) using a single screw extruder have great effects on the physicochemical characteristics of ready-to-eat extruded foods,” the researchers wrote.
Density, expansion and color
For example, increasing grasshopper meal resulted in extruded snacks with a higher density and lower expansion ratio, they said. Inclusion also increased total color difference, resulting in darker snacks, and lower water absorption.
However, the researchers said that if used at low levels, grasshopper meal could be successfully incorporated into maize snacks.
In terms of sensory acceptance – appearance, color, aroma, texture, flavor and overall acceptability – the “highest acceptance” was with a grasshopper inclusion rate of 8.11g per 100g. The researchers said this likely had something to do with the brown color and characteristic flavor associated with snacks containing high levels of grasshopper meal.
“Through the extrusion conditions used in this study, it was possible to obtain a ready-to-eat snack with acceptable physicochemical and sensory properties, while at the same time taking advantage of an unconventional protein source from blends of nixtamalized maize flour and grasshopper meal by incorporating up to 8.11g/100g of grasshopper meal, without affecting its physicochemical properties and acceptance,” the researchers wrote.
Source: Food Science and Technology
Published online March 2018: doi.org/ 10.1111/ijfs.13774
Title: “Physicochemical properties of ready-to-eat extruded nixtamalized maize-based snacks enriched with grasshopper”
Authors: R. Cuj-Laines, et al.