ABSTRACT
Two strategies were combined and applied in this study to achieve a desired structure and texture of gluten free crackers and to reduce the calorie content. The first strategy is increasing structural heterogeneity of crackers and doughs and a separated-dough method was developed. A butter dough and a water dough were prepared separately and mixed together and the influence of mixing time was investigated. In the second strategy, which is the incorporation of a structuring material, powdered cellulose and fibrillated cellulose were incorporated in formulation to replace flour and pregelatinised starch with enhanced health benefits of low calorie and high fibre. Powdered cellulose played the role of the skeleton of the gluten free crackers. A laminar structure was observed in crackers when powdered cellulose was initially added to the butter dough. The crackers exhibit high thickness, hardness and fracturability and sharp sound emission which are typically observed in wheat crackers. Pregelatinised starch can be replaced by fibrillated cellulose at a lower addition level.
Subject(s)
Cellulose , Flour , Food Handling/methods , Glutens , Starch/chemistry , Dietary Fiber , Triticum/chemistryABSTRACT
The production of gluten free crackers is challenging because the formation of a gluten network is required. This study investigated the effects of psyllium seed husk powder (PSY), methylcellulose (MC), pregelatinised starch (PGS), and cold water swelling starch (CWSS) on gluten free crackers made of rice flour. The evaluations of pasting properties, dough rheological properties, textural properties, acoustic emissions, and structures were included in this study. Gluten free cracker doughs were more solid-like compared to wheat doughs based on their frequency dependence shown in the mechanical spectra. However, PGS significantly increased the fluid-like property and shapeability. The addition of MC at a high level significantly modified the pasting profile and a secondary swelling and breakdown might occur. As for the crackers, PSY and PGS crackers had comparable textural properties and sound release to wheat crackers, while CWSS crackers were slightly weaker. However, MC did not improve the textural properties compared to rice crackers because the interaction between the MC molecules was limited at the low water addition level, which limited its functionality in cracker making.
Subject(s)
Methylcellulose/chemistry , Psyllium/chemistry , Snacks , Starch/chemistry , Elasticity , Food Handling , Glutens/analysis , Oryza/chemistry , Powders/chemistry , Rheology , Seeds/chemistry , Triticum/chemistry , Viscosity , Water/chemistryABSTRACT
Contribution of methylcellulose (MC), psyllium seed husk powder (PSY), and water addition level to gluten free bread quality and correlations between dough rheological properties and bread qualities were investigated by response surface design and principal component analysis. The generalised Maxwell model was applied to estimate the relaxation frequency of gluten free doughs. The addition of PSY has a complex influence on pasting viscosity at high temperature and an additional peak was observed. MC significantly influenced dough extensibility and work of adhesion, which are good predictors of bread volume and textural properties. Other rheological responses are less significantly correlated to specific volume, but they are sensitive to formulation variations, reflect dough structures and stability, related to proving behaviours, and correlated to loaf concavity. An inappropriate combination of water and hydrocolloids might lead to problems such as low stability of doughs, overexpansion, and weak crumb structure at high water addition levels, or, in contrast, high rigidity of dough, a trap of excessive air during mixing, and restrained gas cell expansion with high hydrocolloid addition and low water addition.
