Technological quality of wheat infested with Rhyzopertha Dominica F. (Coleoptera: Bostrichidae)

Abstract

Due to its negative impact on the yield and quality of stored grains, the aim of this research was to study the influence of Rhyzopertha dominica F. on rheological properties of wheat flour obtained from grains infested by examined pest. A rheological laboratory device - Mixolab was employed in order to simulate the production process of bread (from the beginning of dough mixing until the end of bread baking). Wet gluten and gluten index, as significant flour quality parameters, were also determined. The flour of wheat varieties Planeta and Kruna was used in these experiments. The samples of both varieties infested with R. dominica (infested samples) were characterized and compared to their uninfested counterparts (control samples). Infested samples expressed a lower gluten index content, greater weakening of the gluten network upon mixing and heating, as well as lower starch gelatinization viscosity in comparison to control samples. Changes in the gluten index value were more pronounced in Planeta variety which was characterized with a higher degree of infestation. Determined changes in rheological properties of infested wheat were mainly dependent on a degree of infestation. However, a varietal dependency on the intensity of changes in technological quality cannot be neglected.

Zbog negativnog uticaja na prinos i kvalitet uskladištenog žita, cilj istraživanja je proučavanje uticaja Rhyzoperta dominica F. na reološke osobine pšeničnog brašna dobijenog od zrna infestiranog ispitivanom štetočinom. Za simulaciju proizvodnje hleba (od zamesa do krajnjeg proizvoda – hleba) korišćen je reološki laboratorijski uređaj – Mixolab. Takođe, određen je i sadržaj vlažnog glutena i gluten indeks koji su značajni parametri kvaliteta brašna. U eksperimentu je korišćeno brašno sorti pšenice Planeta i Kruna. Ispitani su uzorci obe sorte infestiranih sa R. dominica (infestirani uzorci) i upoređeni sa odgovarajućim neinfestiranim uzorcima (kontrola). U poređenju sa kontrolnim uzorcima, infestirani uzorci pokazali su manji sadržaj glutena, veće slabljenje glutenske mreže prilikom mešenja i zagrevanja, kao i manji viskozitet i želatinizaciju skroba. Promene u vrednosti gluten indeksa bile su izraženije kod sorte Planeta kod koje je utvrđen veći procenat infestacije.Utvrđene promene u reološkim osobinama infestirane pšenice zavisile su, prvenstveno, od stepena infestacije pšenice. Međutim, intenzitet promena tehnološkog kvaliteta uslovljen je i uticajem sorte, koji ne može biti zanemaren.