Effects of drying methods (hot air, microwave, and superheated steam) on physicochemical and nutritional properties of bulgur prepared from high-amylose and waxy hull-less barley

Background and objectives Bulgur, an ancient and traditional food extensively consumed in Turkey and the Middle East, has been gaining popularity elsewhere as a nutritious and convenient cereal product with prolonged shelf life. The cooking, drying, and comminution methods used for bulgur production may affect the color, yield, chemical composition, nutritive quality, and physical properties of bulgur. The objectives of this study were to produce bulgur from high-amylose and waxy hull-less barley (Hordeum vulgare L.) varieties and to investigate the effects of different drying methods: hot air, microwave, and superheated steam on the physicochemical and nutritional properties of barley bulgur. Findings Different drying methods applied in this study for the preparation of barley bulgur had significant effects on the physicochemical and nutritious properties of the final products. Bulgur products from high-amylose barley (cv. CDC Hilose) contained lower amounts of proteins, but higher amounts of ash, arabinoxylans, resistant starch, total dietary fiber, and vitamin E than bulgur products from waxy barley (cv. CDC Marlina). However, bulgur products from CDC Marlina exhibited significantly higher solubility of beta-glucans compared with bulgur from CDC Hilose. Conclusions Overall, the optimal quality characteristics in terms of high bulgur yield, short cooking time, low cooking losses, high beta-glucan solubility, and high retention of vitamin E were achieved for bulgur prepared from grain dried with superheated steam at 110 degrees C. The second best results were obtained for bulgur prepared from the microwave-dried grain. Some differences in composition and properties of bulgur prepared from waxy and high-amylose barley were related to genetic variations and differences in starch composition. The higher content of total dietary fiber in bulgur products from CDC Hilose was partly attributed to a higher content of resistant starch formed during the processing of this high-amylose barley. Significance and novelty Barley has been long considered a wholesome and nutritious grain, and the results of this study clearly showed that it can be used for the preparation of bulgur, a convenient and functional food product. The use of superheated steam as a drying method for the preparation of barley bulgur proved to generate product with superior properties, especially when compared to conventional hot air drying.