The effects of four hydrocolloids (guar, xanthan gum, carboxylmethylcellulose (CMC), and hydroxypropylmethylcellulose (HPMC)) in three concentrations (0.1, 0.5, and 1 % w/w flour basis), on Barbari (Iranian bread) was investigated. Farinograph parameters, physical properties (specific volume, oven spring, height to width ratio, crumb to crust ratio), and the moisture content of fresh bread were analyzed. CMC and HPMC had the most noticeable effect on dough rheological properties; leading to a more strengthened dough. The hydrocolloids also improved the bread's physical properties. In addition, the best effect on moisture content was observed by 0.5% CMC, followed by 0.5% and 1% HPMC. Hydrocolloids did not unfavourably influence the sensory properties of bread. All sensory parameters were improved using hydrocolloids. Consequently, despite the improving effect of all hydrocolloids, cellulose derivatives could have better uses in bread-making processes.Keywords: Barbari, bread, hydrocolloids, rheology, sensory properties, quality *To whom correspondence should be addressed. E-mail: Milani.jafar@yahoo.com
IntroductionBread is a staple in the diets of most Middle Eastern families. Barbari is one of the most famous types of bread found in many countries such as Iran, Turkey, and some Arab countries. It has an oval shape, and is typically 70 − 80 cm in length, 25 − 30 cm in width, and 1.5 − 2 cm thickness in most parts that reaches to 2.5 − 3 cm in two ends (Qarooni, 1994). It is usually made from flour of 78% extraction.As demands for greater variety and healthier foodstuffs, including bread, are increasing and the general public are more conscientious of the appearance and quality of food products, food industries and researchers have to find ways to produce high-quality food products with longer shelf life. One of the most influential methods is to use additives including hydrocolloids. Hydrocolloids are generally water soluble polysaccharides which have recently been taken into consideration as bread improvers. They improve taste, texture, mouthfeel, moisture control, physical properties, and overall product quality (Xue and Ngadi, 2009). Some breadimproving effects of hydrocolloids were reported by previous researchers (Rosell et al., 2001;Sharadanant and Khan, 2003;Guarda et al., 2004;Bárcenas et al., 2009;Polaki et al., 2010). The improving effect of sodium alginate, xanthan, κ-carageenan and HPMC on the quality of fresh bread was investigated (Guarda et al., 2004). While all hydrocolloids were able to reduce the dehydration rate of bread crumb during storage, sodium alginate and HPMC showed exceptional moisture retention (Davidou et al., 1996). It has also been reported that HPMC and κ-carrageenan could likewise affect the specific volume, hardness, moisture content and staling of bread obtained from partially baked bread after being stored in sub-zero or low temperatures (Bárcenas et al., 2004;Bárcenas and Rosell, 2006).The purpose of this study was to compare the effect of four hydrocolloids (guar, xanthan g...