Textural characteristics of ready-to-eat breakfast cereals produced from different types of cereal and with varying water addition during extrusion process

Abstract

U radu je ispitan utjecaj dodatka pšeničnog, kukuruznog i rižinog brašna te različite količine dodane vode (21 %, 23 % i 27 %) u procesu ekstruzije na strukturu ekstrudiranih žitarica za doručak. Uzorci su pripremljeni sa i bez slatkog premaza. Teksturalna svojstva suhih ekstrudiranih kuglica i kuglica pripremljenih kao obrok s mlijekom ispitana su pomoću senzorskih metoda i instrumentalno pomoću analizatora teksture TA.XT Plus. Weibullova jednadžba se koristila za nelinearnu regresijsku analizu eksperimentalnih podataka za apsorpciju mlijeka i promjenu hrskavosti u pripremljenom obroku tijekom vremena. Hrskavost suhih ekstrudiranih uzoraka bez premaza je bila mnogo veća od hrskavosti uzoraka s premazom. Najveću hrskavost imali su uzorci od čiste pšenične krupice i brašna, a najmanju, uzorci od mješavine pšenične krupice i kukuruznog brašna. Povećanjem količine dodane vode u procesu ekstruzije smanjivala se hrskavost gotovog proizvoda. Sposobnost apsorpcije mlijeka i gubitak hrskavosti u obroku s mlijekom bili su mnogo jače izraženi i brži kod uzoraka bez premaza u odnosu na uzorke s premazom.Textural characteristics of ready-to-eat breakfast cereals were evaluated in order to determine the influence of wheat, corn and rice flour, as well as a varying water addition during the extrusion process. Extruded breakfast cereal balls were made of wheat semolina in combination with wheat, corn or rice flour. Three different levels of water addition (21 %, 23 % and 27 %) were used during the extrusion process. Samples were prepared with and without surface sugar coating. Sensory and instrumental assessments (TA.XT Plus) were used to evaluate textural attributes of dry samples and samples during immersion in milk. Weibull equation was used for nonlinear estimation of experimental data obtained for milk absorption and crispiness as a function of time. Crispiness of dry extruded balls without coating was much higher than for samples with coating. The highest values for crispness were observed for wheat extruded balls and the lowest for samples with corn flour addition. Increasing water addition during the extrusion process significantly increased crispness of ready-to-eat breakfast cereals. The rate of milk absorption and loss of crispiness were significantly higher for samples without coating than for samples with coating