Empleo del psyllium para el desarrollo de nuevos productos a base de cereales.

Los hidrocoloides son ingredientes muy utilizados en la industria alimentaria debido principalmente a dos características: su solubilidad y su viscosidad. Sin embargo, los hidrocoloides son considerados aditivos y, en vista de la demanda actual por productos “clean label”, es necesario buscar alternativas naturales que tengan propiedades similares. El psyllium es un ingrediente natural, con propiedades funcionales similares a de la goma xantana, que presenta grandes ventajas nutricionales, debido a su alto contenido en fibras. Así se ha demostrado su acción positiva sobre diversas enfermedades o disfunciones del organismo, como el estreñimiento, la diarrea, el síndrome de intestino irritable (SII), el cáncer de colon, la diabetes y la hipercolesterolemia. Además, el psyllium es uno de los sustitutos del gluten más utilizados en la elaboración de panes comerciales sin gluten a nivel mundial, junto con el HPMC, la goma xantana y la goma guar. Sin embargo, los efectos de la incorporación del psyllium en productos horneados están poco estudiados. Se sabe que el psyllium tiene interesantes propiedades gelificantes y espesantes, por ello, la presente tesis evalúa el efecto del psyllium en las propiedades del almidón de maíz, ya que el almidón es una de las alternativas a la harina de trigo más utilizadas en la elaboración de panes comerciales, y otros productos sin gluten. A partir de este estudio y mediante una mejor comprensión de las propiedades funcionales del psyllium, se observó que su uso en la elaboración de panes sin gluten podría afectar a la hidratación de dichas masas, lo que alteraría los efectos de este hidrocoloide en la masa y en la calidad final de los panes. Por lo tanto, esta tesis también evalúa el efecto del psyllium sobre la hidratación de los panes sin gluten, utilizándolo como único sustituto del gluten y comparando sus efectos con otros hidrocoloides. La alta capacidad de absorción de agua del psyllium también hace que pueda funcionar como sustituto de la grasa. Este efecto puede ser útil en la fabricación de productos de bollería más saludables, ya que estos productos suelen tener grandes cantidades de grasa en su formulación. Así, en esta tesis también se estudian los efectos de la utilización de una mezcla de psyllium y agua para sustituir la grasa en las formulaciones de bizcochos y galletas para producir productos finales más sanos, empleándose diferentes niveles de sustitución de la grasa. Previamente se estudia la influencia del tamaño de partícula de harinas de maíz para la elaboración de galletas sin gluten. El estudio del efecto de la sustitución de la grasa en la formulación de galletas se realizó tanto en galletas con gluten como en galletas libres de gluten. El empleo del psyllium en diferentes porcentajes de sustitución del almidón, mostró un aumento de las propiedades de hidratación del almidón y su efecto fue similar al de la goma xantana. Para los geles elaborados sin exceso de agua, ambos hidrocoloides disminuyeron su dureza. A pesar de presentar pequeñas diferencias en la temperatura de formación de pasta, el comportamiento viscoso del psyllium y de la xantana son distintos a altas concentraciones, en las cuales el psyllium aumenta el setback y la temperatura de formación de la pasta. El efecto del psyllium sobre la hidratación de panes sin gluten fue analizado y comparado con otros hidrocoloides (HPMC y goma xantana), en masas elaboradas con almidón de maíz y harina de arroz. En todos los casos, las formulaciones con almidón de maíz tuvieron mayor volumen específico que las elaboradas con harina de arroz. Las formulaciones con psyllium mostraron un comportamiento similar con respecto al volumen específico y la pérdida de peso, en relación a la goma xantana. El HPMC produjo panes con mayor volumen específico, pero al compararse volúmenes específicos similares, los panes con HPMC presentaron mayor dureza que las formulaciones con psyllium o goma xantana. Distintas mezclas de psyllium y agua fueron evaluadas como sustitutos del aceite en bizcochos, empleándose sustituciones del 25%, 50% y 75%. Las mayores sustituciones del aceite produjeron bizcochos finales con una corteza más clara y volumen específicos menores, pero sin diferencias significativas en comparación con el control. El test de aceptabilidad mostró que bizcochos con un 25% menos de aceite no tuvieron diferencia significativa frente al control y que los bizcochos con el 75% de sustitución obtuvieron buena aceptabilidad, con una puntuación de 7 sobre 9. En la elaboración de galletas es necesario la presencia de un cierto porcentaje de partículas finas en la harina, pues ellas son las responsables por dar cohesividad a la masa y así se permite su correcto laminado. Tamaños de partículas mayores producen un mayor grado de expansión y menor dureza en las galletas finales. Al sustituir toda la grasa de galletas, con y sin gluten, por una pasta de psyllium y agua se obtuvieron galletas con menor grado de expansión, diámetros pequeños y mayor dureza. Las galletas con gluten presentaron una humedad final mayor que las sin gluten. Estas características hicieron que las galletas tuviesen baja aceptabilidad por los consumidores y este resultado fue más evidente en las galletas sin gluten.Hydrocolloids are widely used as ingredients in the food industry mainly due to two characteristics: their solubility and their viscosity. However, hydrocolloids are considered food additives and, in view of the current demand for "clean label" products, it is necessary to look for natural alternatives that have similar properties. Psyllium is a natural ingredient, with functional properties similar to xanthan gum, and presents great nutritional advantages, due to its high fibre content. Thus, it has been shown that psyllium has a positive effect in the treatment of diseases or body’s dysfunctions, such as constipation, diarrhoea, irritable bowel syndrome, colon cancer, diabetes and hypercholesterolemia. In addition, psyllium is one of the most widely used gluten substitute in formulations of worldwide commercial gluten-free breads, such as the HPMC, xanthan gum and guar gum. However, the effects of incorporating psyllium into baked products have been little studied. It is known that psyllium has interesting gelling and thickening properties. Therefore, this thesis evaluates the effect of psyllium on the properties of maize starch, since this starch is one of the most used alternatives to wheat flour in the production of commercial gluten-free breads, and other gluten-free products. From this study and through a better understanding of the functional properties of psyllium, it was observed that its use in the production of gluten-free breads could affect the hydration of these doughs, which would change the effects of this hydrocolloid on the dough and on the final quality of the breads. Therefore, this thesis also evaluates the effect of psyllium on the hydration of gluten-free breads, using it as the only gluten substitute and comparing its effects with other hydrocolloids. The high-water absorption capacity of psyllium also makes possible its use as a fat substitute. This effect can be useful in the manufacturing of healthier baked products, as these products often have great amount of fat in their formulation. Thus, this thesis also studies the effects of using a mixture of psyllium and water to replace fat in cakes and cookies formulations to produce healthier final products, using different levels of fat replacement. Previously, the influence of the particle size of maize flour on the production of gluten-free cookies was studied. The study about the effect of fat substitution in cookies formulation was carried out both in gluten-content and gluten-free cookies. The use of psyllium in different percentages of starch substitution, showed an increase in the hydration properties of starch and this effect was similar to that of xanthan gum. For gels made without excess water, both hydrocolloids decreased their hardness. Despite small differences in pasting temperature, the viscous behaviour of psyllium and xanthan gum are different at high concentrations, where psyllium increases the setback and the pasting temperature. The effect of psyllium on the hydration of gluten-free breads was analysed and compared with other hydrocolloids (HPMC and xanthan gum), in doughs made with maize starch and rice flour. In all the cases, the formulations with maize starch had a higher specific volume than those made with rice flour. Psyllium formulations showed similar behaviour with respect to specific volume and weight loss, in relation to xanthan gum. The HPMC produced breads with higher specific volume, but when similar specific volumes were compared, HPMC breads were harder than formulations with psyllium or xanthan gum. Different mixtures of psyllium and water were evaluated as oil substitutes in cakes, using substitutions of 25%, 50% and 75%. The higher oil replacements produced final cakes with lighter crust and lower specific volume, but they had no significant differences compared to the control. The test of acceptance showed that cakes with less 25% of oil did not differ significantly from the control and the cakes with 75% of oil substitution obtained good acceptability, with a score of 7 out of 9. In cookies elaboration is necessary the presence of a certain percentage of fine particles in the flour, because they are responsible for giving cohesiveness to the dough and thus allows proper lamination. Large particle sizes produce a higher degree of expansion and lower hardness in the final cookies. The total replacement of fat in cookies, with and without gluten, through using a paste of psyllium and water, resulted in cookies with a lower degree of expansion, small diameters and great hardness. Cookies with gluten had a higher final moisture content than those without gluten. These characteristics were responsible for the low acceptability of these cookies by consumers and this result was most evident in the gluten-free cookies.Doctorado en Ciencia e Ingeniería Agroalimentaria y de Biosistema

Effect of Hydration on Gluten-Free Breads Made with Hydroxypropyl Methylcellulose in Comparison with Psyllium and Xanthan Gum

Producción CientíficaThe use of hydrocolloids in gluten-free breads is a strategy to improve their quality and obtain products with acceptable structural and textural properties. Hydration level (HL) optimization is important to maximize the hydrocolloids effects on dough and bread quality. This study evaluated the optimum hydration level (OHL) for gluten-free breads prepared with different starch sources (rice flour or maize starch) and hydroxypropyl methylcellulose (HPMC) in comparison with psyllium husk fibre and xanthan gum. Breads with the same final volume and the corrected hydration (CH) were evaluated. The hydration is a key factor that influences the final characteristics of gluten-free breads. Breads made with HPMC had greater dependence on the HL, especially for preparations with maize starch. Psyllium had similar behaviour to xanthan with respect to specific volume and weight loss. Breads manufactured with maize starch and HPMC had low hardness due to their great specific volume. However, in breads made with rice flour, the combined decreased hydration and similar specific volume generated a harder bread with HPMC than the use of psyllium or xanthan. Breads made with HPMC presented higher specific volume than the other hydrocolloids, however combinations among these hydrocolloids could be evaluated to improve gluten-free breads quality.European Regional Development Fund (0612_TRANS_CO_LAB_2_P

Wasted bread flour as a novel ingredient in cake making

Producción CientíficaBread is one of the most wasted products in both industry and retail. This study analysed the use of bread flour of various particle sizes (1000 lm, 500 lm and 200 lm) in different percentages for sponge formulations (10% and 20%) and layer cakes (10%, 20% and 30%). Viscosity, microstructure and den- sity of batters, as well as specific volume, texture and colour of cakes were evaluated. The inclusion of bread flour change batter microstructure. Viscosity does not affect the sponge batters but it tends to increase in the layers, mostly in the case of finer flours. The specific volume is reduced in sponge cakes while hardness is generally increased, even with the lowest percentages of bread flour. In layers, this reduction in volume is only visible at the highest doses of flours below 500 microns with no changes in hardness.Junta de Castilla y León (project VA177P20)TRANSCOLAB FEDER-Interreg España-Portugal (project 0612_TRANS_CO_LAB_2_P

Effect of the particle size of pear pomace on the quality of enriched layer and sponge cakes

Pear pomace (PP) is a by-product of the fruit industry with a high content of fiber. Its potential as an ingredient at 15% or 30% level for sponge and layer cakes was investigated. Three PP powders with different particle sizes (fine, medium and coarse) were obtained. Microstructure, density and viscosity were evaluated in batter, and specific volume, texture and color in the final product. When PP was added, less uniformity in bubble distribution was observed in batters, particularly at higher particle sizes. Cake specific volume significantly diminished with increasing amounts of PP. For sponge cakes, the decrease in specific volume was the highest for the finest particle size of PP. In general, increasing PP addition increased hardness and reduced elasticity, cohesiveness and resilience but the effect depended on the particle size. In general, better textural attributes were obtained with medium and coarse particle sizes. These results indicate that PP of an adequate particle size could be a promising fiber source for different cake formulations.Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-2-R) and the European Regional Development Fund (FEDER

Influence of marine hydrocolloids on extruded and native wheat flour pastes and gels

Producción CientíficaExtruded and native wheat flours were combined with agars (gracilaria and gelidium) and carrageenans (κ-carrageenan and ι-carrageenan) to modify their paste and gel properties. Combinations of extruded flours with hydrocolloids produced an increase in the hydration properties (swelling volume and water holding and water binding capacities). All hydrocolloids (particularly ι-carrageenan) also produced an increase in hydration properties after combination with native flours. With regard to the pasting properties of native flours combinations, all hydrocolloids produced an increase in peak viscosity (particularly gelidium agar), but only agars decreased the onset temperature of gelatinization and increased breakdown, indicating a different mechanism of action. In the presence of extruded flour, the incorporation of hydrocolloids increased the cold viscosity of flours in very different ways depending on the hydrocolloid. Both native and extruded flours exhibited higher G’ and G’’ values and a lower tanafter the incorporation of carrageenans, which, together with the lower dependence on frequency, would produce stiffer and more stable pastes/gels. Based on gel properties, greatest hardness with native and extruded flours was achieved by the incorporation of carrageenans. In general, carrageenans, besides producing stiffer and more stable pastes, gave rise to harder and clearer gels compared to those made with agar, for both their combination with extruded and native wheat flours. Meanwhile, pastes made with combinations of extruded flours and agar showed higher thixotropy

Effects of adding chickpea and chestnut flours to layer cakes

Producción CientíficaChestnut and chickpea flours have interesting nutritional characteristics and can be incorporated into layer cake formulations. This study aims to evaluate the effect of incorporating mixtures of these flours with wheat flour in the elaboration of layer cakes. With this aim, layer cakes were elaborated with the three different flours. Mixes of 50% of these flours and a mixture of the three flours in the same proportion were analysed. Batter density, microstructure and viscosity, as well as the specific volume, texture and acceptability of layer cakes were evaluated. Chickpea flour reduced the batter density and increased viscosity compared to wheat flour, while chestnut flour reduced viscosity and did not clearly affect density. Although both flours produced layer cakes with lower specific volume, as well as less cohesive and springiness, the effect on specific volume was clearer in chestnut flour. With 50% of chickpea flour, it was possible to obtain layer cakes with the same specific volume and hardness as those made with wheat flour. Layer cake acceptability decreased with the reduction in wheat flour, regardless of the type of flour incorporated. No improved acceptability has been found when combining chickpea and chestnut flours.Junta de Castilla y León (VA177P20)TRANSCOLAB FEDER-Interreg España-Portugal project (0612_TRANS_CO_LAB_2_P

Chickpea and chestnut flours as non-gluten alternatives in cookies

This study proposes the use of a mix composed of chickpea flour and chestnut flour in cookies, aiming to improve their acceptability. Cookie properties and nutritional value were also analysed. The gluten-free cookies were made by using different mixes of chickpea and chestnut flours (0:100, 25:75, 50:50, 75:25, 100:0). Dough rheology and cookie dimensions, texture, external colour and acceptability were evaluated. The presence of the chestnut flour increased the values of G’ and G”, but reduced the loss factor (tan δ) when compared with the doughs made with chickpea flour. Chestnut flour also decreased the diameter and the spread ratio of the cookies, while increasing the hardness and darkening of the cookies. Furthermore, adding chestnut to the flour mixture increased the nutritional quality of the cookies by adding unsaturated fatty acids and fibre. The use of reduced percentages of chestnut flour (25%) resulted in masking the off-flavour of the chickpea flour, which improved the cookie’s acceptability without significantly changing the dough rheology, cookie dimensions, hardness, or lightness.This work was financially supported byFEDER-Interreg España-Portugal programme through the project TRANSCOLAB (0612_TRANS_CO_LAB_2_P). The authors are also grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020). L. Barros thanks FCT through the institutional scientific employment program-contract for her contract, while M. Carocho thanks FCT through the individual scientific employment program-contracts (CEECIND/00831/2018).info:eu-repo/semantics/publishedVersio

Psyllium husk gel to reinforce structure of gluten-free pasta?

Gluten-free pasta is a technological challenge. The effect of Psyllium particle size, processing temperature and gel concentration on the quality of rice-based pasta was investigated. The rheological properties, i.e. maturation kinetics and mechanical spectra, of the Psyllium gels were studied and optimal conditions were set: 160–315 μm particle size, 4 g/100 g Psyllium husk concentration thermally processed at 40 ºC. Cooking quality parameters, texture properties, nutritional composition, antioxidants and digestibility of pasta were determined. Consequently, the use of Psyllium husk in gluten-free pasta showed good overall properties. Moreover, the pregelatinization step of rice flour can be eliminated, resulting in a final gluten-free pasta formulation with Psyllium gel and rice flour (50/50) with high digestibilityinfo:eu-repo/semantics/publishedVersio

Influence of Flour Particle Size Distribution on the Quality of Maize Gluten-Free Cookies

The objective of the present study was to analyse the influence of particle size distribution of maize flour in the formulation of gluten-free cookies. Different cookie formulations were made with three distinct maize flour fractions obtained by sieving (less than 80 µm; between 80 and 180 µm; greater than 180 µm). Cookies dimension, texture and colour were evaluated. Flour hydration properties and cookie dough rheology were also measured. Overall, an increase in maize flour particle size decreases the values of water holding capacity (WHC), swelling volume and G’ (elastic modulus) for the doughs. An increase in average particle size also increases diameter and spread factor of the cookies but decreases their hardness. A higher percentage of thick particles is more effective to reduce cookie hardness, but a certain percentage of thinner particles is necessary to give cohesion to the dough and to allow formation of the cookies without breaking. Cookies with a larger diameter also presented a darker colour after baking

Assessing Acerola Powder as Substitute for Ascorbic Acid as a Bread Improver

Bread is one of the most widely consumed products in the world. The use of oxidants is common in bread production, but consumers are demanding products with less additives. Acerola is the fruit with the highest ascorbic acid content and, once dried, it can be used as an oxidant in baking. The use of acerola powder in bread making and its effect on bread quality is studied in this article and compared with the addition of ascorbic acid. For this purpose, flour properties and dough behaviour were analysed with a farinograph and an alveograph. Breads were elaborated with white wheat flour and wholemeal flour; specific volume, loaf height, weight loss, texture, colour, and cell structure were analysed. Acerola powder had similar effects to ascorbic acid: it increased the alveographic strength and the tenacity of the doughs without reducing extensibility; it incremented dough development time (DDT) and dough softening; it increased the specific volume of white wheat breads, and it reduced the hardness of white and wholemeal breads, without significant changes in crust or crumb colour. Therefore, acerola powder can be a natural alternative to the use of ascorbic acid as an improver in bread making