Impact of Guar and Wheat Bran on the Physical and Nutritional Quality of Extruded Breakfast Cereals

Abstract

Two non-starch polysaccharides, guar gum and wheat bran, were used at 15% replacement level in a cereal base to produce an extruded breakfast cereal product from both wholemeal and high-ratio wheat flour mixes. The inclusion of the non-starch polysaccharides into the flour bases had no significant effect on the expansion ratio of the products. However, the product density and bulk density of the extruded products increased with guar gum and wheat bran addition. The pasting properties of the raw flour and polysaccharide base as well as the extruded products were altered with the incorporation of polysaccharides, with guar gum-enriched products showing elevated peak and final viscosity readings. This appeared to be related to moisture manipulation and hence the regulation of gelatinisation. In vitro starch hydrolysis of the raw bases and the extruded samples illustrated that the extrusion process significantly increased the availability of carbohydrates for digestion. Additionally, the inclusion of non-starch polysaccharides in the raw bases significantly reduced the rate and extent of carbohydrate hydrolysis. This potentially glycaemic reducing action was also evident in the extruded products where the incorporation of guar gum at 15% yielded a reduction of starch hydrolysis of 36% in the wholemeal base and 32% in the high-ratio white wheat flour base.

The physico-chemical characteristics of extruded snacks enriched with tomato lycopene

“…doi:10.1016/j.foodchem.2010.05.071 lubricating effect on the melt. This interferes with the air cell formation and limits the starch gelatinisation required for expansion of the snacks, as a result the snacks will be less expanded and hard in texture (Ainsworth, Ibanoglu, Plunkett, Ibanoglu, & Stojceska, 2007;Brennan, Merts, Monro, Woolnough, & Brennan, 2008;Camire, 1998;Yanniotis, Petraki, & Soumpasi, 2007). To compensate, severe extrusion processing at high temperature and shear is needed to decrease the melt viscosity and produce well expanded products enriched with tomato derivatives (Altan, McCarthy, & Maskan, 2008;Huang, Peng, Lu, Lui, & Lin, 2006;Yagci & Gogus, 2008).…”

“…Product density: The product density was determined by the poppy seed displacement method applied to 1 l of extruded products (Brennan et al, 2008). Variation in the product density of the product is largely dependant on the proportion of voids or bubbles that were trapped in the extruded products as they solidified from the extruder.…”

Phenolic profile and carbohydrate digestibility of durum spaghetti enriched with buckwheat flour and bran

“…The influence of fibre on the carbohydrate digestibility and postprandial blood glucose levels has been brought to light in many in vitro studies Brennan & Samyue, 2004;Brennan et al, 2012;Brennan et al, 2008) and human studies (Cummings et al, 1996;Raben et al, 1994;Reader et al, 1997;Wisker & Feldheim, 1990;Wisker et al, 1992).…”

“…The method employed by Brennan et al (2008) in determining in vitro carbohydrate digestibility was used. Two grams of previously cooked and minced spaghetti were mixed with 30 mL of distilled water and 0.8 mL of 1 M HCl to achieve a pH of 2.5.…”

Starch-Galactomannans Mixtures: Rheological and Viscosity Behavior in Aqueous Systems for Food Modeling

“…Brennan et al [62] evaluated the effects of the addition of dietary fiber (wheat bran, guar gum, inulin, hi-maize, and swede) at different concentrations (5-15%) and found that peak and final viscosities among the different extruded products increased with the addition of guar gum. Guar gum decreased readily digestible starch, being more effective than wheat bran.…”