Physico-chemical properties of corn starch modified with cyclodextrin glycosyltransferase

Cyclodextrin glycosyltransferase (CGTase) has been used to produce cyclodextrins (CDs) from starches, but their ability to modify starches has been barely explored. The effect of CGTase on corn starch at sub-gelatinization temperature (50 °C) and at different pH conditions, pH 4.0 and pH 6.0, was evaluated. Biochemical features, thermal and structural analysis, oligosaccharides and CDs content were studied. Microscopic analysis of the granules confirmed the enzymatic modification of the starches obtaining structures with irregular surface and small pinholes. The extent of the starch modification was largely dependent on the pHs, being higher at pH 6.0. This was also confirmed by the low viscosity of the resulting pastes during a heating and cooling cycle. Thermal parameters were not affected due to enzymatic treatment. Modified starches were less susceptible to undergo α-amylase hydrolysis. CDs released were higher for samples treated at pH 4.0. Therefore, CGTase modification of corn starches at sub-gelatinization temperature offers an attractive alternative for obtaining porous starches with different properties depending on the pH conditions.Financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2011-23802, AGL2014-52928-C2-1-R), the European Regional Development Fund (FEDER) and Generalitat Valenciana (Project Prometeo 2012/064). A. Dura would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness.Peer reviewe

Role of enzymes in improving the functionality of proteins in non-wheat dough systems

40 pages, 3 figures, 2 tables.-- Available online 25 September 2015Gluten free systems lack the viscoelastic network required to resist gas production and expansion during baking. Enzymatic treatments of the GF flours have been proposed initially for creating protein aggregates that mimic gluten functionality but then also for modifying proteins changing their functionality in GF systems. To better exploit the technological function and the potentials of enzymatic processing for improving GF bread quality, it is important to understand the key elements that define the microstructure and baking functionality of GF batters as compared to wheat dough. In this review, some keys are pointed out to explain the different mechanisms that are available for understanding the action of enzymes to effectively design GF viscoelastic matrixes. Focus will be on protein modifying enzymes, because they play a decisive role in the formation of the fine network responsible for improving the expansion of rice batters.Financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R), the European Regional Development Fund (FEDER).Peer reviewe

Influence of germination time of brown rice in relation to flour and gluten free bread quality

The effect of germination time on physicochemical characteristics of brown rice flour and its effect on gluten free bread qualities have been investigated. Germination was carried out at 28 °C and 100 % RH for 12, 24 and 48 h; brown rice and soaked brown rice was also analyzed. Significant changes on hydration and pasting properties of brown rice flour were found during germination. The starch degradation by enzyme activity could be evidenced with the decrease in viscosity and water binding capacity (WBC). No significant effect in specific volume, humidity and water activity of the gluten free bread was found as germination time increase, but a significant softness of the crumb was obtained. However, at 48 h of germination, the intense action of α amylase could result in excessive liquefaction and dextrinisation, causing inferior bread quality. Overall, germinated rice flour showed appropriate functionality for being used as raw ingredient in gluten free breadmaking.Authors acknowledge the financial support of Spanish Scientific Research Council (CSIC), the Spanish Ministry of Economy and Sustainability (Project AGL2011-23802), and the Generalitat Valenciana (Project Prometeo 2012/064). F. Cornejo acknowledges the financial support of Secretaría Nacional de Educación Superior, Ciencia, Tecnología e Innovación (SENESCYT, Ecuador). Instituto Nacional de Investigaciones Agropecuarias from Ecuador (INIAP) is thanked for providing the BR cultivars and Biotechnological Research Center of Ecuador (CIBE, Ecuador) for the laboratories facilitiesPeer Reviewe

Physicochemical properties of long rice grain varieties in relation to gluten free bread quality

30 pages, 3 figures, 7 tablesThe aim of this study was conducted to determine the breadmaking potential of six long-grain rice varieties (INIAP 14, INIAP 15, INIAP 16, INIAP 17, F09 and F50) and to identify any flour characteristic governing their breadmaking behavior. Pasting parameters, thermal parameters assessed by differential scanning calorimetry and bread quality parameters (specific volume, color, and crumb texture profile analysis) were assessed. Results confirmed the suitability of long-grain rice varieties for breadmaking. Nevertheless, significant differences were observed in flour properties among varieties. A significant correlation was observed between specific volume of the gluten-free bread (GFB) with swelling power (r = 0.71, P < 0.01), breakdown viscosity (r = −0.97, P < 0.01) and conclusion temperature (Tc) of gelatinization (r = 0.81, P < 0.05). Moreover, a strong correlation was found between cohesiveness and properties of rice flour such as peak temperature (Tp) (r = −0.96, P < 0.001), DH (r = 0.71 P < 0.05) and swelling volume (r = 0.82, P < 0.05). The quality characteristics of the gluten-free breads made of long-grain rice flour were comparable to those reported in commercial GFB. INIAP 14 and F09 were the most promising varieties for bakery applications. Results suggested that the most important parameters of rice flour when defining breadmaking performance of GFB would be WBC, SP, SV, Tp, Tc and enthalpy.financial support of Spanish Scientific Research Council (CSIC), the Spanish Ministry of Economy and Sustainability (Project AGL2011-23802), and the Generalitat Valenciana (Project Prometeo 2012/064). F. Cornejo acknowledges the financial support of National Secretary of High Education, Science, Technology and Innovation (SENESCYT, Ecuador).Peer reviewe

Comparison of porous starches obtained from different enzyme types and levels

The objective was to compare the action of different hydrolases for producing porous corn starches. Amyloglucosidase (AMG), α-amylase (AM), cyclodextrin-glycosyltransferase (CGTase) and branching enzyme (BE) were tested using a range of concentrations. Microstructure, adsorptive capacity, pasting and thermal properties were assessed on the porous starches. SEM micrographs showed porous structures with diverse pore size distribution and pore area depending on the enzyme type and its level; AMG promoted the largest holes. Adsorptive capacity was significantly affected by enzymatic modification being greater influenced by AMG activity. Unexpectedly, amylose content increased in the starch treated with AMG and BE, and the opposite trend was observed in AM and CGTase treated samples, suggesting different mode of action. A heatmap illustrated the diverse pasting properties of the different porous starches, which also showed significant different thermal properties, with lower To and Tp. Porous starch properties could be modulated by using different enzymes and concentrations.Financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R) and the European Regional Development Fund (FEDER). Y. Benavent-Gil would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness.Peer reviewe

Glycemic Response to Corn Starch Modified with Cyclodextrin Glycosyltransferase and its Relationship to Physical Properties

Corn starch was modified with cyclodextrin glycosyltransferase (CGTase) below the gelatinization temperature. The porous granules with or without CGTase hydrolysis products may be used as an alternative to modified corn starches in foods applications. The amount and type of hydrolysis products were determined, containing mainly β-cyclodextrin (CD), which will influence pasting behavior and glycemic response in mice. Irregular surface and small holes were observed by microscopic analysis and differences in pasting properties were observed in the presence of hydrolysis products. Postprandial blood glucose in mice fed gelatinized enzymatically modified starch peaked earlier than their ungelatinized counterparts. However, in ungelatinized enzymatically modified starches, the presence of β- CD may inhibit the orientation of amylases slowing hydrolysis, which may help to maintain lower blood glucose levels. Significant correlations were found between glycemic curves and viscosity pattern of starches.financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2011-23802 and AGL2014-52928-C2-1-R), the European Regional Development Fund (FEDER) and GeneralitatValenciana (Project Prometeo 2012/064). A. Dura would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness. This research was performed in part at the Processed Foods Research, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, United States.Peer reviewe

Mixing properties of fibre-enriched wheat bread doughs: A response surface methodology study

8 pages, 2 figures, 5 tables.-- Published online 29 December 2005.-- The original publication is available at www.springerlink.comFibre-enriched baked goods have increasingly become a convenient carrier for dietary fibre. However, the detrimental effect of fibres on dough rheology and bread quality continuously encourages food technologists to look for new fibres. The effect of several fibres (Fibruline, Fibrex, Exafine and Swelite) from different sources (chicory roots, sugar beet and pea) on dough mixing properties when added singly or in combination has been investigated by applying a response surface methodology to a Draper-Lin small composite design of fibre-enriched wheat dough samples. Major effects were induced on water absorption by Fibrex that led to a significant increase of this parameter, accompanied by a softening effect on the dough, more noticeable when an excess of mixing was applied. Conversely, Exafine increased water absorption without affecting the consistency and stability of dough, which even improved when combined with Swelite. Fibruline showed little effect on dough mixing parameters, but showed synergistic effects with pea fibres. The overall result indicates that the use of an optimised combination of fibres in the formulation of fibre-enriched dough allow improving dough functionality during processing.Peer reviewe

Rheology of different hydrocolloids-rice starch blends. Effect of successive heating-cooling cycles

10 pages, 3 figures, 5 tables.-- Available online 25 November 2010.Hydrocolloids are frequently used for modifying starch functionality. In the present study the possible interaction of three different hydrocolloids – guar gum, hydroxypropylmethylcellulose (HPMC) and xanthan gum – with rice starch was explored by determining the pasting, viscoelastic and swelling properties of the rice starch–hydrocolloids mixtures. The impact of successive heating–cooling cycles on the pasting, viscoelasticity and swelling was also determined. Hydrocolloids tested in the range 0.2–0.8% (w/w) significantly modified the pasting, viscoelastic and swelling properties of rice starch–hydrocolloid pastes (8%, w/w) and the extent of the effect was dependent on hydrocolloid concentration. Guar and xanthan gum mixtures with rice starch had the greatest effect on the pasting properties, whereas HPMC mixtures only changed the viscosity during cooling. The starch–hydrocolloids pastes formed weaker gels compared to those of the starch alone. Rheological results suggested the formation of composite network structures with high frequency dependence. Successive multiple-heating cycles allowed the gel to rearrange resulting in altered gel viscoelasticity and release of water soluble compounds that favour phase separation at the highest hydrocolloid level tested.Financial support from University of California-Davis, Ministry of Education and Science, Spanish Research National Council (CSIC) and Spanish Ministerio de Ciencia e Innovación (Project AGL2008-00092/ALI) is gratefully acknowledged. Dr. Rosell thanks the Spanish Ministry of Education and Science for her grant.Peer reviewe

Improvement of dough rheology, bread quality and bread shelf-life by enzymes combination

12 pages, 2 figures, 6 tables.-- Published online 28 November 2006.Present work seeks to systematically analyse the individual and synergistic effects of some gluten-crosslinking enzymes (transglutaminase, glucose oxidase and laccase), along with polysaccharide and gluten degrading enzymes (alpha-amylase, xylanase and protease), in breadmaking systems. Except glucose oxidase (GO) and laccase (LAC), enzymes affected significantly to viscoelastic properties of dough. Results confirmed the strengthening effect exerted by transglutaminase (TG). However, alpha-amylase (AMYL), xylanase (XYL) and protease (PROT) promoted a similar decrease in all dynamic moduli analysed, particularly after 180 min of incubation. Addition of XYL to TG containing samples showed to be an interesting alternative to prevent excessive dough strengthening. Bread quality parameters were significantly affected by individual enzyme addition, except when LAC was used. TG diminished loaf specific volume and provided a finer crumb structure. Polysaccharide degrading enzymes and PROT led to better shape, greater specific volume and void fraction of loaves. Significant interactions between TG and all the other enzymes except GO, were proved. According to crumb texture evolution during storage, bread staling increased with TG addition, whilst AMYL, XYL and PROT exhibited a significant antistaling effect.This work was financially supported by Comisión Interministerial de Ciencia y Tecnología Projects (MCYT, AGL2002-04093-C03ALI and AGL2005-05192-C04), Consejo Superior de Investigaciones Científicas (CSIC) and Universidad de Valladolid, Spain.Peer reviewe