Felicidad Ronda

Improving gluten-free bread quality by enrichment with acidic food additives

An experimental design has been developed to improve gluten-free bread formulation, on the basis of rice flour and hydroxypropylmethylcellulose (HPMC) as alternative baking ingredients. In order to improve the quality of gluten-free bread, several levels of acidic food additives (acetic acid, lactic acid, citric acid and monosodium phosphate) have been tested. The influence of these compounds on the dough and on bread properties has been determined, including a hedonic sensory test of appearance, odour, taste and texture of bread. Results suggest that monosodium phosphate yields bread producing better texture scores, associated with the highest volumes of the loaf. Discussions are made on the basis of CO2 transport pathway across the HPMC network and simultaneous interactions with acidic food additives present. Chemical properties of the acids justify the breads alveolus size and the preservative effects of acetic acid in the dough.

Improvement of Quality of Gluten-free Layer Cakes

The development and study of new gluten-free foods of high quality that are suitable for people with celiac disease is necessary since there is increasing frequency of people who have been found to be allergic to proteins in wheat flour. Rice is one of the most used cereals in these special foods elaborations. However, replacement of wheat flour by rice flour usually leads to a noticeable decrease in the quality of the products discussed in this study. This work studied the individual and combined influence of xanthan gum (XAN), emulsifier, pregelatinizated starch, and transglutaminase on quality of rice yellow layer cake (YLC) by means of a systematic study based on a two-level half-fractional factorial experimental design. Size and shape, texture, color, crumb grain profile and sensory acceptance were evaluated in YLC. XAN, white egg proteins, and emulsifier showed significant positive effects on volume, texture and crumb grain characteristics. The feasibility of rice YLC reaching acceptable levels of customer satisfaction was demonstrated.

Effect of Nut Paste Enrichment on Wheat Dough Rheology and Bread Volume

The study was carried out to investigate the effect of nuts (almond, hazelnut, peanut, walnut) enrichment (5, 10 and 15%) on the rheological properties of dough using alveograph, consistograph and rheofermentometer measurements. The loaf volume (LV) of bread added nut paste was also determined. The increase in nut percentage increases the dough viscoelastic characteristics (tenacity, extensibility, and strength) and mixing time, but decreased the dough consistency and tolerance, and the CO2 production during fermentation. Loaf volume increased when 5 and 10% of nut paste are added. Dough added walnut paste presented the lowest tenacity, strength and water absorption values, but the highest values in dough development time, tolerance and stability. Dough added almond, hazelnut and peanut paste had a similar behavior during mixing and handling.

Impact of variety type and particle size distribution on starch enzymatic hydrolysis and functional properties of tef flours

Tef grain is becoming very attractive in the Western countries since it is a gluten-free grain with appreciated nutritional advantages. However there is little information of its functional properties and starch digestibility and how they are affected by variety type and particle size distribution. This work evaluates the effect of the grain variety and the mill used on tef flour physico-chemical and functional properties, mainly derived from starch behavior. In vitro starch digestibility of the flours by Englyst method was assessed. Two types of mills were used to obtain whole flours of different granulation. Rice and wheat flours were analyzed as references. Protein molecular weight distribution and flour structure by SEM were also analyzed to justify some of the differences found among the cereals studied. Tef cultivar and mill type exhibited important effect on granulation, bulking density and starch damage, affecting the processing performance of the flours and determining the hydration and pasting properties. The color was darker although one of the white varieties had a lightness near the reference flours. Different granulation of tef flour induced different in vitro starch digestibility. The disc attrition mill led to higher starch digestibility rate index and rapidly available glucose, probably as consequence of a higher damaged starch content. The results confirm the adequacy of tef flour as ingredient in the formulation of new cereal based foods and the importance of the variety and the mill on its functional properties.

Effect of nut paste enrichment on physical characteristics and consumer acceptability of bread

Four kinds of nut paste (almond, hazelnut, peanut, walnut) in three different percentages (5, 10, and 15%) were added to bread formula to study the morphogeometric and textural characteristics, and the consumer acceptability of enriched breads. The change of texture along time was also studied. Control bread presented the lowest volume, water loss and height, and the highest firmness and chewiness. The enrichment with 15% of nut paste caused a decrease in loaf volume, weight loss, cohesiveness, and resilience but an increase in height, firmness, and chewiness. Almond and walnut breads presented the lowest values in firmness and chewiness. The lowest cohesiveness and resilience corresponded to hazelnut bread. The increased firmness during storage was slower in enriched than in nonenriched breads. The adhesiveness, cohesiveness, and resilience decreases were more important in the first 2 days of storage. Breads added with 10 and 15% nut paste showed the highest intent for consumption, persistence, and texture values. Peanut-enriched bread was the least accepted bread. Only a third of the consumers were able to correctly identify the nuts added.

High insoluble fibre content increases in vitro starch digestibility in partially baked breads

Wheat breads prepared from frozen partially baked breads were characterized by their content of rapidly digestible starch (RDS) and slowly digestible starch (SDS) by the in vitro starch digestibility method developed by Englyst. Breads with different contents and types of fibre and breads prepared with different fermentation processes were studied. Bread with inulin and with a double fermentation had the lowest RDS content of 58.8 ± 1.7 and 60.0 ± 1.9 (% dry matter), respectively. Wheat bran bread, seeded bread, triple fermentation white bread and baguette-type bread showed values of RDS between 63.1 ± 1.7 and 65.7 ± 1.7 with no significant differences between them (p < 0.05). The fraction of SDS was higher in wheat breads than in breads with added fibre. The highest values of the starch digestive rate index (SDRI) were obtained by the three types of breads with added fibre, which ranged from 91.8 ± 3.5 to 95.8 ± 3.5 versus 80.2 ± 3.5 to 87.5 ± 3.5 for white wheat breads. A significant (p < 0.01) positive linear correlation between the insoluble fibre content and SDRI was obtained (R 2 = 0.96). Insoluble fibre dilutes and disrupts gluten network and probably weakens the interaction between gluten and starch, which protects starch from digestive enzymes action. Scanning electronic microscopy microstructure of bread crumbs corroborated this statement.

Prolonged frozen storage of partially-baked wheat bread increases in vitro slowly digestible starch after final bake.

Abstract We have studied the effect of the frozen storage time of industrially produced partially-baked wheat bread on starch digestibility, as the conventional production process is substantially modified for this type of bread, and alterations in its nutritional characteristics are therefore possible. The objective of the present study was to determine the effects of frozen storage on in vitro starch digestibility of partially-baked bread after final bake, with the Englyst analytical method. The rapidly digestible starch, expressed as percentage of dry matter ± 95% confidence interval, fell significantly at 63 days, from 51.9 ± 2.9 to 42.7 ± 2.9 whereas the slowly digestible starch increased over this period, from 18.8 ± 5.5 to 29.9 ± 2.7 (P < 0.05). During the frozen storage, changes occur in the composition and structure of partially-baked bread, modifying the in vitro starch digestibility, with a significant reduction in rapidly digestible starch, which is associated with a lower glycaemic response.

Rheological Properties of Gluten-Free Bread Doughs: Relationship With Bread Quality

Little information has been published on the rheological characteristics of gluten-free doughs which greatly vary in consistency, going from batter to dough. The relationships between dough rheology and dough structure and the link between the rheological properties of dough and its behavior during mechanical handling and baking still need to be studied in gluten-free systems. The most frequently used rheological methods applied to gluten-free dough will be presented and briefly explained in this chapter. An overview of the main factors affecting dough rheology and the effect of some common ingredients of gluten-free doughs and how the dough rheology may affect the quality of bread will also be discussed. The design of gluten-free breads remains an empirical task but some conclusions can be drawn from all the rheological and quality studies. The best developed breads were obtained from doughs not too strong or too weak. Nevertheless, consistency seems not to be the sole issue. Pasting properties and other physico-chemical and structural properties of GF matrices also affect the physical quality of the final bread. The high complexity and variability of ingredients used in GF breadmaking, their different nature and properties, are probably responsible for the difficulty of finding a good predictor of bread quality based only in dough rheology.

Influence of milling type on tef injera quality

Injera is an Ethiopian flat bread that is mostly made from tef flour. Injera making on an industrial scale holds a significant economic and social interest but requires a thorough study of how the process variables affect the product quality. The aim of this work was to investigate the effects of mill type (hammer, disc, and blade) on injera sensory quality and starch digestibility. The application of software for the determination of injera quality descriptors and its comparison with visual human eye evaluation was also established. Injera made with disc mill flour had higher overall acceptability (6.6) than that obtained from hammer mill (4.2) and blade mill (4.1) flours. The injera made with blade mill flour obtained the lowest rapidly available glucose and rapidly digestible starch. The outcome of introducing software for the determinations of injera number of eyes was found effective; its difference with human eye determination was insignificant.

Chapter 12 – Rheological Properties of Gluten-Free Bread Doughs: Relationship With Bread Quality

Little information has been published on the rheological characteristics of gluten-free doughs which greatly vary in consistency, going from batter to dough. The relationships between dough rheology and dough structure and the link between the rheological properties of dough and its behavior during mechanical handling and baking still need to be studied in gluten-free systems. The most frequently used rheological methods applied to gluten-free dough will be presented and briefly explained in this chapter. An overview of the main factors affecting dough rheology and the effect of some common ingredients of gluten-free doughs and how the dough rheology may affect the quality of bread will also be discussed. The design of gluten-free breads remains an empirical task but some conclusions can be drawn from all the rheological and quality studies. The best developed breads were obtained from doughs not too strong or too weak. Nevertheless, consistency seems not to be the sole issue. Pasting properties and other physico-chemical and structural properties of GF matrices also affect the physical quality of the final bread. The high complexity and variability of ingredients used in GF breadmaking, their different nature and properties, are probably responsible for the difficulty of finding a good predictor of bread quality based only in dough rheology.