<p>The farming of insects has been shown to require less land,
feed, and water compared to traditional livestock maintenance, while proven to
be a source of high-quality protein. The aversion of the Western culture
towards edible insects is the major hurdle into their incorporation in the
market, unveiling the challenge of integrating them into an existing familiar
product. However, studies have shown that merely pulverizing insects into
edible “flours” possesses difficulties on itself such as low solubility;
severely altering the structural and sensory characteristics of food products
upon their addition. Alternatively, scientists have turned to chemical protein
isolation techniques to create insect flours with improved functionality.
Furthermore, enzymatic proteolysis has shown to aid in extracting the protein
bound to insoluble chitin and enhancing techno-functional properties. While
this promising technique may open a range of possibilities, no research has
been done regarding the incorporation of insect hydrolysates into a food
matrix. The purpose of this work was to explore the production of insect
hydrolysates with improved techno-functional properties and their impact in the
physicochemical, structural, and sensory characteristics on a chosen model
matrix: corn tortillas. Crickets (<i>Acheta domesticus</i>) were chosen due to
their current relevance in the Western market. </p>
<p>Hydrolysates were produced with low (5%), medium (8%), and
high (15%) degrees of hydrolysis (DH) either with Alcalase (AL) or Flavourzyme
(FL). Alcalase cricket protein hydrolysates (CPH) resulted in higher fat
content, which was suspected of possessing surface-activity. Overall, AL
peptides displayed significantly (p < 0.05) higher emulsion and foam
capacity and stability, suggesting stronger amphiphilic activity. On the other
hand, FL peptides were more soluble and had a lower mean molecular weight,
demonstrated by their lower glass transition temperatures. Both of these
developments may be explained by Alcalase endopeptidase activity and
Flavourzyme primarily exopeptidase activity. Treatments resulted in AL-peptides
with large and medium size molecular weights that included hydrophobic terminal
ends, while FL peptides were smaller and likely contained free amino acids. The
difference in molecular weights were seen upon their addition in the raw corn
masa, where AL-CPH increased elastic and viscous behavior compared to control,
whereas the smaller FL-CPH lowered them due to the plasticizing capability of
hydrophilic small peptides. The ability of FL-CPH to interact with corn
macromolecules was observed upon thermal treatment, resulting in FL-tortillas
with superior strength and extensibility compared to AL-tortillas. In fact,
AL-tortillas fragility was seen by the rollability test, showing a complete
disintegration of the tortilla structure. Raman spectroscopy further showed the
heat-induced intermolecular interactions of FL-peptides with the corn
macromolecules. Raman bands at 1049 cm<sup>-1</sup> in FL-tortillas allude to
protein-starch complexes and the <i>gauche-gauche</i> region confirmed the
presence of disulfide bridges in FL-tortillas, both of these developments were
absent in AL-tortillas. Lastly, the formulation of corn chips with these CPH
proved to be globally accepted by a population with diverse neophobia levels,
confirming theories that consumers are willing to eat insects in an “invisible”
format. Flavor and aroma profiles of the chips, quantified by a descriptive
analysis study, revealed no commonalities between the two sets of chips.
AL-chips were characterized as having corn, shrimp, and roasted peanut notes,
while FL-chips were characterized as having tomato, ketchup, and French fry
notes. Overall, enzymatic proteolysis was shown to generate cricket peptides
with different characteristics, both able to be utilize as a functional
ingredient for palatable food products. </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/9973622 |
| Date | 14 January 2021 |
| Creators | Gabriela Calzada Luna (7491338) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Cricket_i_Acheta_domesticus_i_Protien_Hydrolysates_Functional_Properties_and_Application_in_a_Food_Matrix/9973622 |
Page generated in 0.0298 seconds