Microbial Enzymes as Substitutes of Chemical Additives in Baking Wheat Flour—Part I: Individual Effects of Nine Enzymes on Flour Dough Rheology

Combined effects of α-amylase, xylanase, and cellulase coproduced by Stachybotrys microspora on dough properties and bread quality as a bread improver

This study aims to explore the feasibility of introducing, during the manufacture of bakery bread, an enzymatic cocktail coproduced by the fungus Stachybotrys microspora: α-amylases, xylanases and cellulases, using wheat bran as a nutrient source. Among the characteristics of the alveograph (dough tenacity "P" and dough extensibility "L"), the addition of a cocktail of enzymes at a concentration of 2 %, to weak wheat flour, has made it possible to significantly reduce its P/L ratio from 2.45 to 1.41. Furthermore, the use of enzyme cocktails at 2 %, 4 %, and 6 % concentrations increases the brown color of the bread crust. The great reduction in the rate of bread firmness, during storage over 5 days, was obtained in the presence of an enzyme cocktail in comparison with bread control (65.13 N for the control and 22.99 N, 23.24 N, and 18.24 N for bread enriched with enzyme cocktail at 2 %, 4 % and 6 % concentrations, respectively). In conclusion, the enzyme cocktail added can synergistically improve bread dough rheology and bread properties.

Individual and combined effects of α-amylase, xylanase, and cellulase on the breadmaking and nutritional properties of steamed bun enriched in wheat bran

The present study investigates the effects of α-amylase (6 and 10 ppm), xylanase (70 and 120 ppm), and cellulase (35 and 60 ppm) on the physicochemical characteristics and nutritional quality of Chinese steamed bun (CSB) incorporated with 15% wheat bran (WB). Compared to the single enzyme, the combined enzymes improved the specific volume of CSB up to the highest value (2.50 mL/g) and decreased the hardness to the minimum value (299.61 g) when the concentration was 6, 120, 35 ppm. Additionally, the combined enzymes (6, 120, and 35 ppm) significantly (p < 0.05) decreased the total dietary fiber from 14.65% to 13.10% and hence increased the area under the reducing sugar release curve during in vitro digestion from 302.12 to 357.26 mg/g. Consequently, enzymes combination can significantly improve the quality of WB CSB, whereas reduce the nutritional value of WB CSB.

A combined use of different functional additives for improvement of wheat flour quality for bread making

BACKGROUND

Low-protein wheat flour can produce bread with poor texture and appearance, reducing its nutritional value and market appeal. This is a growing concern for both the food industry and consumers relying on wheat as a dietary staple. The present study evaluated the individual and combined effects of bacterial xylanase (BX), maltogenic α-amylase (MG), vital gluten (VG) and ascorbic acid (AA) with respect to improving weak flour properties for bread making.

RESULTS

BX, VG and AA improved gluten Index (GI), whereas MG was employed for optimizing amylolytic-activity in flour. VG increased the water absorption (WA) capacity of flour and prolonged dough development time (DDT). The dough stability (DST) was increased by BX and VG. BX and MG decreased crumb firmness (CF) and showed anti-staling effect. All additives reduced bake loss, increased loaf volume (LV) and retained or improved sensory attributes of bread. However, MG at 60 mg kg-1 (MG60), BX at 30 mg kg-1 (BX30), VG at 5% (VG5) and AA at 50 mg kg-1 (AA50) were found to be the most suitable for evaluating in combinations. Ternary combinations of MG60, BX30, VG5 or AA50 imparted significantly (P < 0.05) positive impacts on GI, WA, DDT, DST, CF, LV and sensory attributes compared to control, individual and binary combinations.

CONCLUSION

The PCA suggested that a combination of MG60 + VG5 was more similar to MG60 + BX30 + VG5, whereas, MG60 + BX30 and MG60 + AA50 were more related to MG60 + BX30 + AA50 combination, but all of these combinations showed the improvement in the characteristics compared to control flour. © 2023 Society of Chemical Industry.

Influence of α-amylase, xylanase and cellulase on the rheological properties of bread dough enriched with oat bran

A better understanding of dough rheology during processing is crucial in the bakery industry, since quality attributes of the final product are influenced by those properties. In this study, we investigated the effects of xylanase, α-amylase and cellulase on the rheological properties of bread dough enriched in oat bran. A DoughLAB was used to measure the mixing characteristics of dough. According to the results, adding a single enzyme did not significantly affect the water absorption, development time, or stability of oat bran dough. In contrast, when blended enzymes were used at high concentrations (10, 120, and 60 ppm), the water absorption, development time, and stability of the oat bran dough were significantly reduced compared to using the single enzyme (62.1%, 7.1 and 6.6 min). It was found that combining α-amylase, xylanase and cellulase resulted in better extensibility and stickiness (16.5 mm and 60.8 g) of oat bran dough than using these enzymes individually. As a result, α-amylase, xylanase and cellulase complemented each other in determining the rheology of bread dough.

A Comparative Assessment of the Baking Quality of Hybrid and Population Wheat Cultivars

The study assessed the quality parameters of grain and flour, the rheological properties of dough and the quality of bread prepared from flour of hybrid cultivars of wheat in comparison with population cultivars of wheat. As the interest in wheat hybrids cultivars from the agricultural and milling industry is growing, their technological value of grain and flour was evaluated at two levels of nitrogen fertilisation (N1—110 kg/ha, N2—150 kg/ha). Increasing the fertilisation (N2) produced a significant influence on the crude protein and gluten content in the flour, as well as the moisture of the crumb and the yield of the dough without impacting other rheological traits and parameters of bread baking process. The performed principal component analysis (PCA) allowed for identification of the best cultivars among the studied wheat cultivars (Hybery and Hyvento). The hybrid cultivar Hyvento was characterised by favourable qualitative traits of the grain (vitreousness, crude protein content) and rheological parameters of the dough (bread volume), however, it had lower baking quality parameters. Among the hybrid cultivars, the best applicability for baking purposes was Hybery due to the favourable values of the baking process parameters and bread quality (bread yield, bread volume, Dallmann porosity index of crumb). Hybrid cultivars of wheat can therefore be used for the production of bread and be an alternative in agricultural production for population cultivars, which will contribute to filling the knowledge gap for the hybrid wheat cultivars.

Evaluation of bio-fenton oxidation approach for the remediation of trichloroethylene from aqueous solutions

In the present study, a Bio-Fenton oxidation approach for the removal of trichloroethylene (TCE) was developed through the optimization of enzyme-based hydrogen peroxide (H₂O₂) production from glucose. Glucose oxidase (GOD) was evaluated for the production of H₂O₂ and the optimized parameters were found to be the oxidation of 60 mM glucose by 1 mg mL^-1 of GOD which yielded a conversion of 88.4% of glucose for subsequent utilization in the Bio-Fenton process. The biologically produced H₂O₂ was further used for the removal of TCE from groundwater samples by addition of ferrous ion to the reaction mixture. To determine the efficiency of hydroxyl radicals generated in Fenton reactions to remove TCE in a cost-efficient way, preliminary experiments such as classical Fenton and pseudo Bio-Fenton were carried out in aqueous solutions containing TCE in order to obtain the optimum conditions and then the efficiency of bio-Fenton was tested in groundwater. Based on these results, almost 97% of TCE was removed from aqueous solution within 30 min of classical Fenton under low pH condition (pH 3.0). While performing pseudo bio-Fenton experiments, the optimum conditions were determined to be pH 7.0 and 30 ppm H₂O₂ which yielded 61% removal of TCE in 30 min. Although a comparatively lower removal (30.2%) in groundwater containing TCE was achieved using Bio-Fenton process, it was at a neutral pH. The process was further enhanced by the addition of hydrogen peroxide after 3 h of reaction and a maximum of 48.4% removal of TCE was observed. Thus, this process will help to prevent the scavenging of the unstable H₂O₂ and can be employed in-situ.

Effects of starch addition on the activity and specificity of food-grade lipases

Lipases are surface-active enzymes, acting on their substrates at the polar/nonpolar interface in emulsions. This study was aimed to test whether their activity, specificity, and the rates of formation/degradation of the various hydrolysis intermediates (i.e., mono- and diglycerides of interest as surface-active agents) could be modulated by adhesion of the triglyceride substrates as a thin layer on the surface of solids. These hypotheses were tested by using an array of food-grade lipases used in bakery, testing various types of starch as the "solid" phase. Starch-dependent increase in the hydrolysis rate was tested by pH-stat techniques on pure triglycerides and on food-grade oils in diluted emulsions. Starch-related improvements in the rate of fatty acids release were most evident at temperatures above 40 °C, and when using maize starch instead of wheat starch. Starch-dependent changes in the nature of the hydrolysis products were tested by chromatographic profiling of ethyl ether extracts from aqueous slurries containing up to 33% fat and 33% starch. Accumulation of mono- and diglycerides as hydrolysis intermediates was found to be modulated by the type of oil being used, by the reaction conditions, as well as by the enzyme nature and amount.

Improving changes in physical, sensory and texture properties of cake supplemented with purified amylase from fenugreek (Trigonella foenum graecum) seeds

Three different concentrations of a purified maltogenic amylase (FSA) from fenugreek (Trigonella foenum graecum) seeds were incorporated into the cake formulation. The addition of FSA at 0.003, 0.005 and 0.01 U/g of cake increased the loaf volume, the number of holes (gas cells), and water absorption. Textural study revealed an improvement of the cake quality, resulting in the decrease of hardness and the increase of cohesion. Environmental scanning electron microscopy was performed on different cakes to evaluate the influence of amylase activity on microstructure. The microstructure observation showed that the FSA had a beneficial effect on starch and crumb properties. The sensory evaluation supported this result and confirmed the beneficial effect of adding FSA on cake odor and crust color. In addition, relationships between physical parameters, instrumentally textural parameters, and sensory characteristics of cake treated with FSA might be used for constructing linear regression analysis models to predict overall acceptability. In fact, overall acceptability of treated cake with FSA at 0.01 U appeared to be the most remarkable one and could be a promising technology to improve the quality of cake.

Recombinant Wheat Endoplasmic Reticulum Oxidoreductin 1 Improved Wheat Dough Properties and Bread Quality

Recombinant wheat endoplasmic reticulum oxidoreductin 1 (wEro1) with considerable ability was expressed in Escherichia coli. The functional roles of wEro1 in flour processing quality were investigated by farinographic, rheological, texture profile analysis, electrophoresis, size exclusion chromatography, scanning electron microscopy, and Fourier transform infrared spectroscopy. wEro1 exhibited an obvious oxidation activity of sulfhydryl groups in small molecule and protein. Addition of wEro1 could strengthen the processing quality of dough, indicated by the improved mixing characteristics, viscoelastic properties, and bread qualities. These improvement effects of wEro1 could be attributed to the formation of macromolecular gluten polymers and massive gluten networks by disulfide cross-linking. Additionally, the increased β-turn structure further demonstrated the enhancement of dough strength. Moreover, the amount of peroxide in dough was improved significantly from 2.36 to 2.82 μmol/g of flour with 0.15% wEro1 treatment. Therefore, the results suggested that wEro1 is a promising novel flour improver.