Impact of red flour beetle infestations in wheat flour and their effects on dough and bread physical, chemical, and color properties

Abstract

The impact of Tribolium castaneum on the quality and technological suitability of bread-making wheat flour was evaluated. The aim of this study is to investigate whether insect-infested flours can be used, after pest removal, avoiding the common use of insecticides and flour waste. The tests were carried out with wheat flour infested red flour beetle with 500 adults/kg (N1), 1000 adults/kg (N2) and 2000 adults/kg (N3), for two weeks. Flour color, total starch, protein and water contents, mineral composition and flour acidity were studied. The technological properties of the respective doughs and of bread were characterized. The results showed that infested flours acidity was significantly higher (N1, N2 and N3 = 0.3 g H2SO4/100 g) than the control (0.1 g H2SO4/100 g), the total starch content decrease, from 78 g (control) to 70 g/100 g dm (N3), and protein content did not significantly change, 7 g/100 g (control) to 8 g/100 g (N2); flour infested showed darker greyish tone which colour differences ΔE higher than 5, while the bread crust was lighter; the gelatinization properties of starch were slightly influenced by degree of infestation with gelatinization temperature reduction of about 5◦c. There was not impact on the structure of the doughs from infested flours measured by rheology. The extensibility of the doughs, before and after fermentation, was moderately affected by the insects. For the respective breads, they kept their softness for longer, without significant volume change. These results encourage insect tolerance on grains and derivatives, avoiding chemical toxic insecticides and food waste. This pretends to be a contribution to pest management and decision support systems, prevention, and control of losses, relevant subject to stored products.