[Effects of barley beta -glucan on some rheological properties of wheat flour]

ABSTRACT

In the recent years, hydrocolloids have been the subject of much investigation as functional foods. In the present study beta-glucan was acid-extracted from barley and its effects on some rheological properties of wheat flour were investigated. Beta-glucanwas extracted from whole barley flour by the acid-extraction method. The total beta-glucan content of the extracted gum was determined using the Megazyme assay kit. The beta-glucan gum obtained was added to 3 samples of wheat flour, namley Nol, Setareh, and their Mix [5050] flours at a level of 0.0%, 0.5%, or 1%. Doughs wer prepared from the what flour samples and theirrheological properties investigated. The SPSS software was used for data analysis. A completely randomized design was used for the experiment, the means being compared using the LSD test. The rheological behavior of beta-glucan-enriched doughs depended on flour quality and beta-glucan concentration. All the farinographic characteristics, specially water absorption, improved with increasing beta -glucan concentration. Extensograph results also showed that resistance to extension and extensibility increased with increasing beta -glucan concentration. The mix flour with 1% beta -glucan showed the best rheological properties [p<0.05]. In all the treatments addition of beta-glucan increased water absorption, dough resistance time, dough development time, extensibility, resistance to extension, and the surface area under the curve, and it decreased dough loss. Beta-glucan at1% level showed better rheological properties as compared to the 0.5% sample. Overall, considering all the chemical and rheological tests, it can be concluded that addition of 1% beta-glucan to mix flour results in the best treatment, although it is not the most effective