RESPONSE SURFACE MODELING OF INSTRUMENTAL TEXTURE AND COLOR IN HYBRID BEEF BURGERS CONTAINING GAMMA-IRRADIATED TENEBRIO MOLITOR FLOUR

Edible insects have garnered significant attention for their potential to provide high-quality protein, and Tenebrio molitor is one of the most studied and commercially viable edible insect species. As research advances, researchers have investigated traditional and emerging technologies—such as gamma irradiation—to develop safer insect-based ingredients with optimized technological properties. However, adding Tenebrio molitor flour (TMF) to meat products may affect their structural and physicochemical characteristics, particularly texture and color, which are important attributes of product quality. This study aimed to evaluate the effects of gamma irradiation dose applied to Tenebrio molitor flour and its incorporation level on the instrumental texture and color of hybrid beef burgers. A face-centered central composite design comprising 11 experimental runs, including three center-point replicates, was employed. Gamma irradiation doses ranged from 5 to 10 kGy, while beef replacement with insect flour varied from 5 to 12%. The flour was irradiated before incorporation into the burger formulations. Instrumental texture was assessed through texture profile analysis, including hardness, springiness, cohesiveness, and chewiness, while color was determined using CIELAB parameters (L*, a*, and b*). Response surface methodology was applied to investigate the effects of both experimental factors. Hardness increased with flour incorporation, and
the fitted model showed a high coefficient of determination (R² ≈ 0.995). Flour incorporation also influenced springiness (p ≈ 0.002), whereas irradiation dose did not show a significant linear effect on this parameter. The observed textural changes may be associated with alterations in the protein network and water distribution caused by partial meat replacement with insect flour, influenced by irradiation-induced changes in protein structure and functionality. For the b* coordinate of cooked burgers, flour incorporation (p ≈ 0.003) and its interaction with irradiation dose (p ≈ 0.025) were significant, with the fitted model explaining approximately 80.7% of the observed variability. Changes in instrumental color may reflect insect-derived pigments and differences in light scattering within the meat matrix. At the same time, irradiation-related protein modifications and browning reactions may also contribute to color development during cooking. These findings indicate that the incorporation level of gamma-irradiated T. molitor flour plays an important role in determining the instrumental texture and color characteristics of hybrid beef burgers. The results contribute to understanding the technological implications of using insect-derived ingredients in meat reformulation.

Funding Agencies: Financier of Studies and Projects (FINEP) (PROTINA nº 01.23.0776.00)

Acknowledgements: Federal University of São João Del Rei, Institute of Energy and Nuclear Research, University of Campinas, Center for the development of Nuclear Technology (CDTN) and Financier of Studies and Projects (FINEP).