Effects of enzymatic modification of soybean protein on the pasting and rheological profile of starch–protein systems

ABSTRACT Reformulation of traditional food systems to introduce new ingredients may change their structure and perceived texture. Interactions between proteins and starch during processing can markedly influence starch gel network structure and rheological profile. The present work aimed to study the effects of soybean protein and the products of enzymatic modification on the pasting and rheological profile of corn and cassava starch. The behaviour of those protein enriched gels during storage was also assessed. Soybean protein isolate (SPI) was incubated with endopeptidase (AL) or food grade microbial transglutaminase (TG). Pasting and rheological behaviour, water retention capacity and structure of protein-and hydrolysed protein-starch gels were analyzed. Protein incorporation increased the viscosity of starch suspension during and after heating. SPImodified proteins increased peak viscosity. Only the structural modifications brought by TG on SPI increased the final viscosity during starch pasting and the storage modulus (G′). This modulus (G′) of the gelled systems decreased with the addition of AL-treated protein isolate. Light and fluorescence microscopy showed that SPI formed a continuous phase, like a network, in the gelled system. Different network structures and rheological properties can be obtained when SPI are modified by protease and transglutaminase enzymes, which may be very useful for designing new food products

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

Particle Size and Hydration Properties of Dried Apple Pomace: Effect on Dough Viscoelasticity and Quality of Sugar-Snap Cookies

Apple pomace (AP) is a by-product of the juice industry, rich in dietary fiber (45.06%), which is generated in large quantities. The objectives of the present work were to evaluate the effect of the particle size and the level of replacement with AP on the quality of sugar-snap cookies. Dehydrated AP was ground to three different particle sizes (d (4,3) = 362, 482, 840 μm) to substitute 15% and 30% of wheat flour in cookie formulations. The quality of dough and cookies was evaluated in terms of rheological properties, color, texture and global acceptability of the final product. When the AP particle size decreased, the water absorption properties (WHC, WBC) were higher (33 and 10 % respectively for the lowest and the highest particle size). For both replacement levels the smallest particle size (362 μm) led to the highest dynamic moduli of dough. The spread ratio (SR) of the cookies diminished when the particle size decreased (from 6.4 to 4.8 corresponding to AP840 and AP362 respectively). The lowest SRs were obtained for the 30% replacement level except for AP362. When employing AP with the largest particle size (840 μm) the cookies were less hard (48.7N). The addition of AP to sugar-snap cookies led to higher global acceptability scores than for control cookies. The sensory attribute that most differentiated the cookies with AP was their pleasant taste being the taste score always higher than the control one.Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-2-R) and the European Regional Development Fund (FEDER) and the University of La Plata (Projects 11/X661 and 11/X771) and CONICET from Argentin

Antioxidantes naturales: efecto sobre la estabilidad oxidativa del aceite de nuez (<i>Juglans regia</i> L.)

Por su elevado nivel de insaturación (> 68%), el aceite de nuez es altamente susceptible al deterioro termo y foto-oxidativo. En este trabajo se propone analizar el efecto de algunas sustancias naturales y sintéticas sobre la estabilidad oxidativa y la conservación del aceite de nuez. Las condiciones de iluminación empleadas (luz fluorescente, intensidad 800 Lux) promovieron la formación de productos de oxidación primarios, aún en los aceites aditivados; los antioxidantes evaluados resultaron poco eficaces como inhibidores de oxidación fotosensibilizada. En ausencia de luz, todos los tratamientos con agregado de antioxidantes fueron igualmente eficaces para inhibir la formación de productos de oxidación durante el periodo de almacenamiento. La valoración de la capacidad antirradicalaria de los aceites aditivados permitió determinar que: a) TBHQ es un efectivo inhibidor de radicales libres en el aceite de nuez, b) su actividad no resulta afectada por la luz, pero es dependiente de la concentración, c) el extracto de romero y el palmitato de ascorbilo no ejercen un efecto aditivo sobre la actividad del TBHQ.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Utjecaj svojstava pšeničnog brašna i tijesta na tehnološku kakvoću slanih proizvoda od kvasnog lisnatog tijesta

The effect of protein composition and content on the characteristics and properties of laminated baked products has been studied for a long time. However, there are no flour quality parameters related to its suitability to produce yeast-leavened laminated salty baked products. The relationships among flour characteristics, laminated dough pieces and baked products were studied in order to establish flour quality parameters and help predict the quality of the products. Yeast-leavened salty laminated products made with hard wheat flour had better quality properties than the products made with soft wheat flour. Hydrophilic components and a high gluten network quality are responsible for the generation of a rigid structure and viscous dough. Consequently, during baking, the dough rises rather than extends laterally and does not experience any change in the expected shape. Among the analysed flour characteristics, glutenin macropolymer content, lactic acid and sodium carbonate solvent retention capacities together with dough viscosity and resistance to deformation were the variables which influenced the most the quality of yeast-leavened salty laminated products.Utjecaj sastava i udjela proteina na svojstva pečenih proizvoda od lisnatog tijesta ispituje se već dugi niz godina, no još nije istraženo koji su parametri kakvoće brašna prikladni za proizvodnju slanih proizvoda od kvasnog lisnatog tijesta. Stoga je ispitan odnos između karakteristika brašna, sirovog lisnatog tijesta i pečenih proizvoda, da bi se utvrdilo koji je tip brašna najpovoljniji te na osnovu toga predvidjela kakvoća dobivenih proizvoda. Slani proizvodi od kvasnog lisnatog tijesta izrađenog od oštrog pšeničnog brašna imali su bolja svojstva od onih dobivenih od glatkog pšeničnog brašna. Tijesto je zahvaljujući hidrofilnim sastojcima i pogodnoj strukturi glutena bilo čvrsto i elastično, pa tijekom pečenja nije gubilo oblik, jer je raslo a nije se širilo. Udjel makropolimera glutenske strukture, sposobnost zadržavanja otopina mliječne kiseline i natrijevog karbonata, te viskoznost i elastičnost tijesta najviše su utjecali na kakvoću proizvoda od kvasnog lisnatog tijesta

Microencapsulación mediante secado por aspersión: efecto sobre la estabilidad oxidativa de los aceites de Chía (Salvia hispanica L.) y nuez (Juglans regia L.)

Evaluar la estabilidad oxidativa del AC y del AN (con y sin el agregado de ER) microencapsulados en condiciones de almacenamiento prolongado.http://www.fcq.unc.edu.ar/documentos/Libro_resumenes_JP6-Final.pdfFil: Curti, María I. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina.Fil: Martinez, Marcela L. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Martinez, Marcela L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Ciencia y Tecnología de los Alimentos; Argentina.Fil: Roccia, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina.Fil: LLabot, Juan M. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica.Fil: Maestri, Damián M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Maestri, Damián M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Ciencia y Tecnología de los Alimentos; Argentina.Fil: Ribotta, Pablo D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina.Otras Ciencias Química

Caracterización física y obtención de parámetros de fluidización de germen de trigo

El germen de trigo es el embrión del grano de trigo, presenta un elevado contenido de tocoferoles y proteínas y ácidos grasos y proteínas de alta calidad. A su vez, contiene enzimas con elevada actividad que limitan su periodo de aptitud a unos pocos días. El objetivo del presente trabajo fue caracterizar físicamente las partículas de germen de trigo para determinar los parámetros de diseño para un proceso de fluidificación térmica con aire. Los ejes principales de las partículas fueron determinados mediante análisis de imágenes y sus dimensiones y parámetros geométricos fueron calculados. La densidad de lecho fijo y la porosidad del lecho fueron determinadas. Los estudios fluido-dinámicos nos permitieron determinar los coeficientes, laminar (277,46±17,48) y turbulento (7,79±0,69) de la ecuación de Ergun y la velocidad de mínima fluidificación (0,35±0,02 m/s).Wheat germ is the embryo of de wheat seed, it contains a high tocopherol and protein content, and high quality proteins and fatty acids. Also, wheat germ has a considerable enzymatic activity that limits its shelf life. The aims of the study were to physically characterize wheat germ particles to determine their design parameters of thermal fluidization process with air. The principal axes of the particle were measured by image analysis, and their dimensions and geometric parameters were calculated. The fixed bed density and the void fraction were measured. The fluid-dynamic studies allowed us to determine laminar (277.46±17.48) and turbulent (7.79±0.69) coefficients of the Ergun equation and the minimum fluidization velocity (0.35±0.02 m/s).Centro de Investigación y Desarrollo en Criotecnología de Alimento

Enzymatic modifications of pea protein and its application in protein-cassava and corn starch gels

6 pages, 4 figures, 2 tables. Available online 4 August 2011.The interactions between starch and proteins during processing influence pasting and rheological properties of starch and produce modifications on starch gel structure. Enzymatic modifications have been proposed for overcoming the limitations of using proteins as food ingredients. This work aimed to study the impact of native and enzymatically modified pea proteins on the properties of protein–starch (from cassava or corn) gels. Pea protein isolate (PPI) was incubated with endopeptidase (AL) or microbial transglutaminase (TG). Pasting profile, rheological behaviour and water retention capacity of protein–starch gels were analyzed. Protein (native and enzymatically modified) incorporation increased the viscosity of both corn and cassava starches during gel preparation. However, the hydrolyzed protein reduced drastically the increment of viscosity of protein–starch gels. The addition of PPI led to corn starch network that shifted from an elastic-like nature to a more viscous-like, whereas the opposite effect was observed in cassava gel network. TG- and AL-treated proteins led to a decrease of both G′ and G″ moduli of protein–starch gels, and AL-treated proteins showed the highest decrease on these parameters. Hydrolyzed proteins also favoured the syneresis of the protein–corn starch gel, whereas crosslinked proteins tended to reduce it. Enzymatic modifications of pea proteins affected significantly pasting and rheological properties of protein–starch gels.Authors would like to thank the CSIC and the Spanish Ministerio de Ciencia e Innovación (Project AGL 2008-00092 ALI), the Consejo Nacional de Ciencia y Técnica (CONICET) and the Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) for financial support. P.D. Ribotta would like to thank Conselleria de Educacio I Ciencia of the Comunidad Valenciana for his postdoctoral grant.Peer reviewe

Effect of microbial transglutaminase on the protein fractions of rice, pea and their blends

7 pages, 3 figures, 2 tables.-- Published online 19 September 2007BACKGROUND: Transglutaminase (TG) is a transferase that has been used for crosslinking proteins. In general, those interactions are promoted within proteins of the same nature, and very few studies have been conducted for creating new bonds between proteins from different sources catalysed by TG. The effect of TG on the protein fractions of rice flour, pea protein isolate and their blends was studied by using different electrophoretic analyses (simple sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and multistaking SDS-PAGE under reducing and non-reducing conditions). RESULTS: TG induced the disappearance of numerous protein bands as a consequence of the formation of large protein polymers, linked by isopeptidic and disulfide bonds, with reduced solubility. The main protein fractions involved in those interactions were the albumins and globulins, from the pea protein isolate, and the rice flour; and the glutelins were also crosslinked. CONCLUSION: Composite flours containing the rice flour and the pea protein isolate are proposed for obtaining a protein-enriched dough with better amino acid balance. Also a protein network formed of protein aggregates of high molecular weight can be created in the presence of transglutaminase.This work was financially supported by the Spanish Ministerio de Educación y Ciencia Project (MCYT, AGL2005-05192-C04-01) and Consejo Superior de Investigaciones Científicas (CSIC).Peer reviewe

Gleditsia triacanthos Galactomannans in Gluten-Free Formulation: Batter Rheology and Bread Quality

Gluten-free batters, in general, require the incorporation of agents to control their rheology; this role is commonly played by hydrocolloids. New natural sources of hydrocolloids are under permanent research. In this regard, the functional properties of the galactomannan extracted from the seed of Gleditsia triacanthos (Gledi) have been studied. In this work, we evaluated the incorporation of this hydrocolloid, alone and in combination with Xanthan gum, in gluten-free batters and bread and compared it with Guar gum. The incorporation of hydrocolloids increased the viscoelastic profile of the batters. Gledi addition at 0.5% and 1.25% increased the elastic modulus (G&prime;) by 200% and 1500%, respectively, and similar trends were observed when Gledi-Xanthan was used. These increases were more pronounced when Guar and Guar-Xanthan were used. The batters became firmer and more elastically resistant because of the addition of hydrocolloids; batters containing Gledi had lower values of these parameters than batters containing Gledi-Xanthan. The addition of Gledi at both doses significantly increased the volume of the bread compared to the control by about 12%, while when Xanthan gum was included, a decrease was observed, especially at higher doses (by about 12%). The increase in specific volume was accompanied by a decrease in initial crumb firmness and chewiness, and during storage, they were significantly reduced. Bread prepared with Guar gum and Guar-Xanthan gum combinations was also evaluated, and the trends observed were comparable to that of bread with Gledi gum and Gledi-Xanthan gum. The results showed that Gledi addition favors the production of bread of high technological quality