Bread fortified with dietary fibre extracted from culinary banana bract: its quality attributes and in vitro starch digestibility

The effect of fortification of dietary fibre (DF) on dough rheology, quality characteristics and in vitro starch digestibility of bread was studied. Bread was prepared incorporating DF (2–4 g per 100 g of flour mixture). Rheological study of dough showed an increase in dough stiffness and elasticity with higher incorporation of the DF. The results of chemical composition revealed that addition of DF increased total DF (19.65 g per 100 g) content of bread. However, incorporation of 2 g per 100 g DF of flour mixture with 66 g per 100 g moisture showed higher water retention and specific volume of 86.76% and 5.83 cm³ g⁻¹, respectively, which was close to control bread. Improved textural property with acceptable sensory attributes was observed for bread fortified with 2 g per 100 g DF of flour mixture and 66 g per 100 g moisture content. Incorporation of DF (2–4 g per 100 g of flour mixture) showed a decrease in rapidly digestible starch (RDS) and an increase in slowly digestible starch (SDS) content with lower predicted glycaemic index (pGI) than control bread.     

Beta Vulgaris root as a natural food colouring in doughnut: Dough rheological properties and bioactive composition

In the present study, the influence of Beta vulgaris root powder (BVP) incorporated at 0%, 5%, 7.5%, 10% and 12.5% levels on the empirical and fundamental rheological characteristics; dough texture properties; nutritional and bioactive components in the doughnut were carried out. The addition of BVP, decreased the WAC (58.4%–51.2%), DDT (6.19–1.31 min), extensibility (148–95 mm), and springiness (4.56–3.24 N) and viscosity parameters to varying extent. The frequency sweep test indicated that both the dynamic moduli increased and G' was higher than G" at all levels indicating the solid elastic structure of the dough. The dimensional characteristics of the doughnuts indicated a decrease in volume (103.3–85 mL) and an increase in weight (35.8–46.7 g) and compression force (11.6–14.5 N). The sensory studies indicated that 10% BVP incorporated doughnut was highly acceptable with higher dietary fibre content. The higher retention of betacyanin (17.88 mg 100 g⁻¹), betaxanthin (12.9 mg 100 g⁻¹), betanin (6.61 mg 100 g⁻¹), TPC (25.74 mg GAE 100 g⁻¹), TFC (77.08 mg QE 100 g⁻¹) and TAC (28.76 mMTE 100 g⁻¹) was observed.     

Evaluation of rheological properties,microstructure and water mobility in buns dough enriched in aleurone flour modified by enzyme combinations

This study aimed to explore the differences between single enzyme and combined enzymes in improving buns dough quality characterised by changes in rheological properties, microstructure and water mobility. The results indicated that xylanase (60 μg g⁻¹)–glucose oxidase (GOX) (40 μg g⁻¹) and xylanase (60 μg g⁻¹)–glucose oxidase (40 μg g⁻¹)–cellulase (30 μg g⁻¹)-modified dough can improve the negative effects of the single enzyme on the dough in terms of extensibility, tenacity and stability, leading to the formation of a softer gluten matrix. This may be due to xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹) and xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹)–cellulase (30 μg g⁻¹)-modified dough reduced the free sulfhydryl and significantly increased water-extractable arabinoxylan content (P < 0.05) and enhanced more less-tightly bound water availability. The microstructure observation showed that xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹) and xylanase (60 μg g⁻¹)–GOX (40 μg g⁻¹)–cellulase (30 μg g⁻¹) modified dough exhibited a more compact and continuous gluten matrix.     

Effects of polyphenol oxidation on in vitro iron availability in faba bean (Vicia faba L.) flour

Tannic acid (TA) and green tea extract (GTE) were added to faba bean flour, before and after incubation with polyphenol oxidase (mushroom tyrosinase), and the effect on in vitro iron availability was investigated. The inhibitory effect of TA and GTE was dose dependent, and the in vitro iron availability decreased from 64.5% in the pure faba bean flour to 9.8% (P < 0.05) with the addition of 1 mg of TA 1 g^?1 to faba bean flour. The addition of 5 mg of GTE resulted in low in vitro iron availability as after the addition of 10 mg of TA (11.6% against 10.3% for 1 mg TA). Incubation of the polyphenols with tyrosinase before addition to the faba bean flour significantly increased the in vitro iron availability. The increase in iron availability was significant (P < 0.05) when amounts of 0.2, 0.5 or 1 mg g^?1 TA or GTE added to faba bean flour, respectively, were oxidised, even with the lowest amount of tyrosinase (150 u). Oxidation of 1 mg TA or GTE with 150 u tyrosinase increased the in vitro iron availability from 10.3% to 15.5% and from 19.2% to 26.1%, respectively. At the 300‐u level, the addition of higher amounts of enzyme (from 600 to 900 u) did not have any effect. The results from the study therefore suggest that the oxidation of polyphenols may be a promising way to increase the availability of iron in polyphenol‐containing legume foods.     

Quality parameters of wheat grain and flour as influenced by treatments with natural zeolite and diatomaceous earth formulations,grain infestation status and endosperm vitreousness

This study investigated the changes in quality parameters of wheat (mealy and vitreous) non-infested and infested with Sitophilus oryzae (L.) caused by treatments with inert dusts: natural zeolite, two diatomaceous earths from Serbia, and a commercial product enhanced DE Protect-It^®.Inert dust treatments, regardless of infestation status, significantly reduced wheat test weight. This was more marked in mealy (8.3%) rather than in vitreous wheat grain (2.7%). Content of silicon dioxide (SiO₂) in flour from infested lots was significantly higher than in non-infested ones. Treatments with all formulations of inert dusts significantly affected flour water absorption in the non-infested wheat lots. Non-infested high vitreous wheat treated with Protect-It^® showed the highest moisture absorption (61.9 g.100 g⁻¹) in comparison with the control (59.7 g.100 g⁻¹). Significant improvement in dough rheology was observed in the infested soft and hard wheat, particularly through rise of dough energy. Small-deformation tests implied certain dough weakening effects of inert dusts in vitreous wheat but this was not observed in standard large-deformation rheological tests.Application of inert dusts shows an ability to improve some aspects of the technological quality of wheat.     

The antioxidant activity and the composition of free and bound phenolic acids in dough of wheat flour enriched by Boletus edulis after mixing and thermal processing

The porcino is good source of phenolics and has been used to enrich wheat flour. The antioxidant activity and the content and composition of free and bound phenolic acids in the dough of wheat and porcino flour mixture (70:30 w/w) were investigated. The free form in the amount of 1305.76 μg g^?1 was the main part of the phenolic content in the flour mixture. By dough mixing, the content of free phenolics increased by approximately 70%. Further thermal processing decreased the content of both forms of phenolics compared to dough after mixing, but the content of free phenolics of 1764.24 μg g^?1 is still higher than in the flour mixture. The stability of the detected phenolic acids during mixing and thermal processing depended on whether they were in free or bound form. After thermal processing, the total content of detected phenolic acids was 683.31 μg g^?1, indicating that approximately 87% of the total content of phenolic acids detected in flour mixture was retained.     

Thermo‐rheological and functional properties of gamma‐irradiated wholewheat flour

The effects of different doses (0, 0.5, 1, 2.5, 5 and 10 kGy) of gamma irradiation on the thermal, rheological and functional properties of the wholewheat flour were evaluated. Water and oil absorption capacity of the flour increased from 85.92% to 91.44% and 1.10 to 1.91 g g^?1 of flour, respectively, with increase in irradiation dose. The dough development time decreased with dose from 4.0 to 3.0 min. The transition temperatures (T_o, T_p and T_c) decreased as the dose increased; enthalpy of gelatinisation (?H) decreased from 5.18 to 4.27 J g^?1 with dose. The flow behaviour showed a shear‐thinning behaviour, and the hysteresis area decreased with dose. The structural recovery decreased with dose. FTIR did not show formation of any new chemical groups.     

Effects of endogenous flour lipids on the quality of short‐dough biscuits

Fractionation and reconstitution techniques were used to study the contribution of endogenous flour lipids to the quality of short‐dough (shortcake type) biscuits. Biscuit flour was defatted with chloroform and baked with bakery fat, but without endogenous lipid. Short‐dough biscuits baked from defatted flour had smaller diameters, and were flatter, denser and harder than control biscuits. Defatted flour shortcake doughs exhibited different rheological behaviour from the control samples, showing higher storage and loss moduli (G′ and G″ values), ie higher viscoelasticity. Functionality was restored when total non‐starch flour lipids were added back to defatted flour. The polar lipid fraction had a positive effect in restoring flour quality whereas the non‐polar lipid fraction had no effect. Both fractions were needed for complete restoration of both biscuit quality and dough rheological characteristics. A study of the microstructure of defatted biscuits revealed that their gluten protein was more hydrated and developed than the gluten of the control biscuits. This conclusion was supported by the higher water absorption of the defatted gluten. Copyright © 2004 Society of Chemical Industry     

Dynamic rheology of wheat flour dough. II. Assessment of dough strength and bread‐making quality

Controlled stress rheometry revealed that differences in wheat flour dough strengths could be observed by means of dynamic rheological measurements in the region of higher stress amplitude (ie >100 Pa). At lower stress amplitude (τ_o) the values of elastic modulus G′ for weak doughs were higher than those for strong doughs, but they decreased substantially beyond 100 Pa stress amplitude (τ_o), such that the G′ values for strong doughs crossed over the G′ values for weak doughs. Beyond a critical value of stress amplitude (ie 100 Pa), true differences in dough strengths could be seen on the basis of their elastic characteristics, because at large deformations protein–protein interactions played a more dominant role in the rheological behaviour of flour doughs. Dynamic rheological analysis demonstrated a very weak inverse relationship (R² = 0.16) between the G′ values of flour doughs and loaf volume data for 12 wheat cultivars of diverse bread‐making performance. However, the G′ values of glutens showed significant positive relationships with bread‐making performance, explaining 73% of the variation in loaf volume. © 2002 Society of Chemical Industry     

Characterisation of jellyfish protein films with added transglutaminase and wasabi extract

The physical, optical, antimicrobial and antioxidant properties of jellyfish protein (JFP) films with added transglutaminase (TGase) and wasabi extract (WE) were studied. Among the plasticisers, 30% sorbitol was the most desirable. The optimal physical properties of the JFP films were obtained when 15 U transglutaminase g^?1 JFP was added. The incorporation of WE affected the physical properties of the JFP films. The tensile strength (21.68–35.25 MPa), elongation at break (10.85–13.25%) and Young's modulus (920.18–1278.9 MPa) of the films increased as WE concentration increased from 0.5% to 1.5%. The thermal gravimetric analysis results revealed that the thermal stability of the JFP films increased with increasing concentrations of WE. The inhibition zones against Escherichia coli O157:H7 and Listeria monocytogenes and antioxidant activity also increased as the concentration of WE increased. Thus, antimicrobial and antioxidant JFP films could be prepared by the addition of WE.     

Incorporation of microbial transglutaminase into non-fat yogurt production

This study investigated the physical, chemical and sensory characteristics of non-fat yogurts treated with microbial transglutaminase (MTGase) at varying concentrations from 0 to 0.5 g L⁻¹. Also, the effect of enzyme inactivation prior to fermentation on the selected properties of the yogurts was studied. Acid development rate was reduced with increasing MTGase doses. Cross-linking of milk proteins by MTGase had a growth-slowing effect on yogurt starter bacteria, which was more pronounced at higher concentrations. Physical properties of the yogurts were improved by MTGase throughout 21-day storage; on the contrary, the production of acetaldehyde was slowed down by increasing MTGase concentrations during the same period. Principal component analysis (PCA) and hierarchial cluster analysis (HCA) clearly differentiated the samples with added MTGase at lower (⩽0.3 g L⁻¹) and higher (0.4–0.5 g L⁻¹) concentrations regarding the physical and sensory properties. The physical and sensory properties of non-fat set yogurt could be improved by incorporating MTGase up to a level of 0.3 g L⁻¹.     

Effect of phenolic acids on the rheological properties and proteins of hard wheat flour dough and bread

BACKGROUND: The effects of different phenolic acids on the rheological properties and gluten proteins of hard wheat flour dough and bread were investigated. Caffeic, ferulic, syringic and gallic acids were each blended with hard wheat flour at a concentration of 4.44 µmol L^?1 g^?1 flour. RESULTS: Mixing time and tolerance were reduced with the addition of phenolic acids. The phenolic acids reduced the maximum resistance to extension (R_max) and increased the extensibility of dough, with effects in the following order: gallic < syringic < ferulic < caffeic acid. The effect on R_max was more pronounced in overmixed dough. Loaf volume was most significantly decreased with the addition of caffeic acid. Extraction of sodium dodecyl sulfate‐soluble high‐molecular‐weight proteins was increased in both mixed and fermented doughs by the addition of ferulic and caffeic acids. The order of influence of the phenolic acids on the rheological properties and protein structure of dough and bread was consistent with that of their antioxidant activity. CONCLUSION: The addition of caffeic and ferulic acids reduced R_max and increased the extensibility of hard wheat flour dough by modifying the high‐molecular‐weight gluten, which resulted in decreased bread volume. Copyright © 2011 Society of Chemical Industry     

Rheological properties of instant fried noodle dough as affected by some ingredients

An experiment was set up to investigate the influence of ingredients such as moisture, gum and starch on the rheological properties of instant fried noodle dough. The noodle dough was formulated using a mixture of wheat flour (100%), 0–0.3% guar gum, 0–7.5% starch and 30–42% moisture. The rheological properties of noodle dough were influenced by the ingredients and their interactions. Increasing moisture content decreased Young's modulus (E) of dough samples. Addition of gum to dough at a lower moisture content of 30% increased E, decreased the energy at break (EB) and increased the storage modulus (G′) values. Interactions of starch and gum influenced changes in the rheological parameters at higher moisture contents. Increasing starch content in noodle dough with a lower gum concentration increased EB to a point beyond which further increase in starch concentration decreased EB. Gum and starch improved the binding and mechanical network in the dough. Insufficient water in the dough apparently reduced cohesion in the dough whereas excess water reduced the functionality of gum and starch. Copyright © 2005 Society of Chemical Industry     

Effect of microbial transglutaminase and setting condition on gel properties of blend fish protein isolate recovered by alkaline solubilisation/isoelectric precipitation

The effect of microbial transglutaminase (M-TGase) (0–0.6 units g⁻¹ sample) and setting condition (25 °C/180 min, 30 °C/120 min, 35 °C/60 min and 40 °C/30 min) on gel properties of blend protein isolate of gutted kilka and silver carp was studied. The protein isolate provided a good substrate for M-TGase activity so that a low amount of M-TGase (0.2 unit g⁻¹ sample) substantially improved textural properties and water holding capacity (WHC) of the gels. Breaking force of the gels was positively affected by M-TGase up to 0.6 unit g⁻¹ sample, but it negatively affected their WHC. Prior setting at 25–35 °C increased the breaking force of proteins compared to directly heated gel, resulting in maximum breaking force at 35 °C/60 min. However, the setting at 40 °C/30 min caused proteolysis, which was reflected in higher amounts of TCA-soluble peptides and gel weakening. Denser microstructure and higher myosin heavy chain polymerisation observed in the gels which experienced the setting was well correlated with improvement in textural properties.     

Effects of japonica rice flour on the mesoscopic and microscopic properties of wheat dough protein

The aim of this study was to study the effects of twelve varieties of japonica rice flour on the gluten protein composition and structure of wheat dough. Experimental results indicated that the addition of japonica rice flour significantly decreased the α-helix structure in the gluten protein sample, but increased the random coil content, indicating that the protein secondary structure became more disordered. The ratio of α-helix/β-sheet structures in the dough supplemented with different varieties of japonica rice flour was decreased, contributing to improved dough stability. Increasing the proportion of japonica rice flour from 10% to 40% significantly decreased the sulfhydryl content of the mixed flour dough. However, the total sulfhydryl content was only positively correlated with the amount of Longdao 19 japonica rice flour, reaching a maximum of 25.34 mol g⁻¹ at 40% japonica rice flour. The gluten structure of mixed flour dough typically forms a porous three-dimensional network, with the Longdao 19, 20, 23 and 25, Longjing 31 and Mudanjiang 31 japonica rice flours leading to improved gluten protein networks. In summary, the supplementation of standard wheat flour with japonica rice flour can alter dough properties and gluten structure.     

Effect of hydroxypropyl methylcellulose,whey protein concentrate and soy protein isolate enrichment on characteristics of gluten‐free rice dough and bread

Due to a lack of gluten, rice dough needed some additives to improve its properties. This study aimed to investigate effect of hydroxypropyl methylcellulose (HPMC), whey protein concentrate (WPC) and soy protein isolate (SPI) on rice dough and bread. HPMC increased water absorption of the rice dough (P ≤ 0.05). Adding SPI (2–4 g per 100 g flour) together with HPMC tended to increase stability time and reduce tolerance index. During fermentation, HPMC increased maximum dough height, while SPI increased final dough height (P ≤ 0.05). All addition improved tan δ (G″/G′) to be comparable to the wheat dough, but it could not improve gas production and retention. Therefore, specific volume, springiness, cohesiveness and chewiness of rice bread were lower than those of wheat bread (P ≤ 0.05). Percentage of small pores in rice bread was reduced to be comparable to wheat bread, by adding WPC. All addition could improve porosity of the rice bread.     

A comparison of the ability of several small and large deformation rheological measurements of wheat dough to predict baking behaviour

The rheological characteristics of twenty wheat flour samples obtained from four organic flour blends and a non-organic control were compared in relation to their ability to predict subsequent loaf volume in the baked bread. The flour samples considered had protein contents that varied between 11–14 g/100 g. Four different rheological methods were employed. Oscillatory stress rheometry on the protein gel extracted from the wheat flour, oscillatory stress rheometry and creep measurement on undeveloped dough samples and biaxial extensional measurements on simple flour–water doughs. None of the fundamental rheological parameters correlated with loaf volume. There was a correlation between the storage modulus of the gel protein and storage modulus for the undeveloped dough (r = 0.85). There was a weak negative correlation between protein content and biaxial extensional viscosity (r = −0.62). Stepwise multiple regression related loaf volume to dough stability time (measured on the Farinograph) and tan (phase angle) for the undeveloped dough samples (overall model r² = 0.54). The results indicate that the four rheological tests considered could not be used as predictors of subsequent loaf volume when the bread is baked.     

The Effects of Vital Wheat Gluten and Transglutaminase on the Thermomechanical and Dynamic Rheological Properties of Buckwheat Dough

The improvement of the processing properties of gluten-free cereals is a challenging issue for cereal technologists. Vital wheat gluten (VWG), transglutaminase (TGase), or combinations of the two have been successfully used to improve the processing properties of food materials. In this study, a Mixolab system and a rheometer were used to investigate the effects of TGase on the thermomechanical and dynamic rheological properties of buckwheat flour dough (BF dough) and a buckwheat flour dough containing 15% VWG (BF-VWG dough). The results indicated that the addition of 1.0% TGase decreased the water absorption and significantly increased the stability, storage modulus (G′), and complex modulus (|G*|) of the BF dough. The presence of 15% VWG had a synergistic effect, enhancing the effectiveness of the TGase in improving the thermomechanical and dynamic rheological properties of the BF-VWG dough. Quantification of the free amino groups showed that the amino groups were more effectively bonded in the BF-VWG dough than in the BF dough when the TGase level exceeded 1.0%. Confocal laser scanning microscopy (CLSM) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis confirmed that the TGase promoted the formation of protein complexes. These data indicate that the combination of VWG and TGase can be used to improve the properties of buckwheat flour for buckwheat-based food production.     

Rheology of Rice Flour Dough with Gum Arabic: Small and Large‐Deformation Studies,Sensory Assessment and Modeling

The absence of gluten protein makes the rice flour doughs difficult to handle when flattened/sheeted products are to be prepared. The rheological, sensory and microstructural changes in rice flour doughs having gum Arabic (0% to 5%, w/w) and moisture contents (44% to 50%) were studied for improving the dough handling characteristics. Rheological parameters like storage modulus (G′) and complex viscosity (η*) decreased with an increase in moisture content while loss angle (δ) increased. A power‐law type equation was suitable to relate angular frequency (ω) with G′, G″, and η* (0.814 ≤ r ≤ 0.999, P ≤ 0.01). An increase in gum and moisture contents increased δ from 6.9° to 15.5° but decreased the energy required for compression/flattening. The 6‐element spring‐dashpot model was suitable (r ≥ 0.991, P ≤ 0.01) for creep curves. The sensory panel had the opinion that dough with a low to moderate hardness between 3 and 4, and stickiness of ≤3.5 was suitable for the purpose of flattening in relation to the preparation of sheeted/flattened products; the appropriate condition for dough formulation was with the moisture and gum contents of 47.0% to 47.9% and 1.55% to 2.25%, respectively to offer the desirability index between 0.50 and 0.52. The microstructure of the rice flour dough in the absence of gum Arabic appeared to possess loosely bound flour particles. The presence of gum provided a coating on flour particles to yield dough having good cohesive microstructure.     

Impact of lecithin incorporation on gel properties of bigeye snapper (Priacanthus tayenus) surimi

Gelling characteristics of bigeye snapper (Priacanthus tayenus) surimi functionalised by lecithin at different concentrations were investigated. Lecithin at ≤1 g 100 g⁻¹ had no impact on breaking force and deformation (P > 0.05). Expressible drip tended to decrease with increasing lecithin level up to 1 g 100 g⁻¹. Lecithin at 1–3 g 100 g⁻¹ improved the whiteness (P < 0.05). Jointed clusters were formed in the gel microstructure with 1 g 100 g⁻¹ lecithin. Gel without and with 1 g 100 g⁻¹ lecithin had the same texture profile and likeness scores (texture, odour and flavour) (P > 0.05). Peroxide value, TBARS content and rancid odour score of gels were changed considerably during refrigerated storage (4 °C/polyethylene bag) for 15 days but lower values of all indices were noticeable in gel with lecithin. Therefore, lecithin at 1 g 100 g⁻¹ was the optimum concentration for stabilising the texture, improving the water holding capacity, whitening the colour and retarding the lipid oxidation of bigeye snapper surimi gel.