Effect of wheat bran dietary fibre on the rheological properties of dough during fermentation and Chinese steamed bread quality

Role of superfine grinding in whole-purple-wheat flour. Part II: Impacts of size reduction on dough properties, bread quality and in vitro starch digestion

This study aimed to enhance bread functionality while maintaining its organoleptic attributes by employing superfine grinding and purple wheat, through characterizing dough properties, bread quality attributes, and in vitro starch digestibility. Compared with dough made from commercial-superfine-whole-wheat flour, the superfine-whole-purple-wheat dough was less strong, comparably extensible, and higher in gassing power during mixing, moulding and proofing, respectively. The subsequent bread quality analysis of crumb grain features and texture indicated that the bread made from superfine-whole-purple-wheat flour was more porous and softer with a larger specific volume (3.21 ± 0.20 cm3/g) than that made from commercial-superfine-whole-wheat flour (2.30 ± 0.17 cm3/g). Additionally, the superfine-whole-purple-wheat bread had a significantly slower glucose release (k = 0.0048 min-1) during in vitro starch digestion as compared to the superfine-whole-wheat bread (k = 0.0065 min-1). Therefore, this study demonstrates that using superfine-whole-purple-wheat flour leads to bread with desirable quality attributes and potential health benefits compared to conventional whole-wheat flour.

Biofortification, metabolomic profiling and quantitative analysis of vitamin B12 enrichment in guava juice via lactic acid fermentation using Levilactobacillus brevis strain KU15152

BACKGROUND

Chemical fortification and dose supplementation of vitamin B12 are widely implemented to combat deficiency symptoms. However, in situ, fortification of vitamin B12 in food matrixes can be a promising alternative to chemical fortification. The present study aimed to produce vitamin B12-rich, probiotic guava juice fermented with Levilactobacillus brevis strain KU15152. Pasteurized fresh guava juice was inoculated with 7.2 log CFU mL-1 L. brevis strain KU15152 and incubated for 72 h at 37 °C anaerobically. The antioxidants, total phenolic compounds, vitamin B12 production, sugars, organic acids, pH and viable count were analyzed at 24, 48 and 72 h of incubation. The fermented juice was stored at 4 °C, and the changes in its functional properties were analyzed at 7-day intervals up to 28 days of storage.

RESULTS

During fermentation, the bacteria cell count was increased from 7.01 ± 0.06 to 9.76 ± 0.42 log CFU mL-1 after 72 h of fermentation and was decreased to 6.94 ± 0.34 CFU mL-1 during storage at 4 °C after 28 days. The pH, total soluble solids, crude fiber, citric acid and total sugars decreased, while titratable acidity, total protein, antioxidants, phenolic compounds and lactic acid contents increased during fermentation. The fermented guava juice exhibited higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS)) radical scavenging activities (85.97% and 75.97%, respectively) at 48 h of fermentation. The concentration of active vitamin B12 in the sample reached 109.5 μg L-1 at 72 h of fermentation. However, this concentration gradually decreased to 70.2 μg L-1 during the storage period. During storage for 28 days at 4 °C, both the fermented and control guava juices exhibited a decline in antioxidant and phenolic compound concentrations. Furthermore, the addition of 20% honey and guava flavor enhanced the organoleptic properties and acceptability of fermented guava juice.

CONCLUSION

The value-added fermented guava juice could be a novel functional food product to combat vitamin B12 deficiency. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The influence of non-starch polysaccharides on the formation mechanism of wheat dough

The study examined the effects of oat β-glucan (OβG), chitosan (CTS), araboxylan (AX), and fructosan (FOS) on wheat dough formation. Adding 0-7 % OβG, AX, and FOS increased SS content, enhancing gluten stability. D-AX and D-FOS showed higher β-sheet structures, higher air retention and gluten network, smaller pores and denser structures, higher elastic and viscosity moduli. Excessive OβG and CTS could reduce the dough stability, and β-turn and β-sheet ratios, respectively. Therefore, B-7AX and B-7FOS exhibited lower hardness indices during storage, leading to a smoother appearance and more orderly gas chamber distribution. The study provides a theoretical foundation for using non-starch polysaccharides in flour-based products.

Enhancing water retention and mechanisms of citrus and soya bean dietary fibres in pre-fermented frozen dough

In recent years, the production of prepared and frozen foods has increased with economic development. However, during freezing, moisture migration forms ice crystals that damage food structure and reduce quality. This study investigates moisture migration changes in pre-fermented dough during frozen storage and effectiveness of Citrus fibre (CF) and Soya dietary fibre (SDF) on quality improvement. Pre-fermented frozen dough properties were evaluated at different freezing storage days with CF and SDF. Results showed frozen storage reduced water retention, converting deeply bound water to weakly bound and free water. Freezable water content increased significantly from 53% (fresh) to 56.95% (60d-control), forming disruptive ice crystals in gluten protein structure. SDF had superior water flow restriction compared to CF, preventing large ice crystal accumulation, enhancing water-holding capacity, and maintaining gluten protein structure. These findings lay a theoretical foundation for improving quality and industrial applications of pre-fermented frozen dough.

Interaction of wheat bran dietary fiber-gluten protein affects dough product: A critical review

Wheat bran dietary fiber (WBDF) is an emerging food additive used for improving the nutritional value of dough products, albeit its adverse effects cannot be ignored. The dilution effect, mechanical shear effect, competitive water absorption, and steric hindrance of WBDF, as well as the non-covalent binding between WBDF and gluten protein, are considered the key mechanisms underlying the WBDF-gluten protein interaction. However, current studies on the interaction are mostly limited to the impact of the interaction on gluten protein and are rarely focused on the quality of products. Therefore, the effects of the interaction on the structural characteristics and aggregation behavior of gluten protein and multiple involved mechanisms are discussed in this review. On this basis, these changes are systematically related to the gluten network structure, dough properties, and product quality. Mitigation measures corresponding to negative impacts also need to be elaborated to guide and standardize the production and development of dough products containing WBDF.

Effects of Incorporating Alkaline Hydrogen Peroxide Treated Sugarcane Fibre on The Physical Properties and Glycemic Potency of White Bread

The consumption of dietary fibres can affect glycemic power and control diabetes. Sugarcane fibre (SCF) is known as insoluble dietary fibre, the properties of which can be affected by physical, chemical, and enzymatic treatments. In this study, alkaline hydrogen peroxide (AHP) treatments were conducted over time (0.5, 1, 3, and 5 h) at 12.6% (w/v) SCF and the effects on the physicochemical and structural properties of the SCF were evaluated. After making dough and bread with the SCF, with and without AHP treatments, the glycemic responses of the bread samples were evaluated. Shorter durations of AHP treatment (0.5 and 1 h) reduced lignin effectively (37.3 and 40.4%, respectively), whereas AHP treatment at 1 and 3 h duration was more effective in increasing particle sizes (50.9 and 50.1 μm, respectively). The sugar binding capacity, water holding capacity (from 2.98 to 3.86 g water/g SCF), and oil holding capacity (from 2.47 to 3.66 g oil/g SCF) increased in all AHP samples. Results from Fourier-transform infrared spectroscopy (FTIR) confirmed the polymorphism transition of cellulose (cellulose I to cellulose II). The morphology of SCF detected under scanning electron microscopy (SEM) indicated the conversion of the surface to a more porous, rough structure due to the AHP treatment. Adding SCF decreased dough extensibility but increased bread hardness and chewiness. All SCF-incorporated bread samples have reduced glycemic response. Incorporation of 1, 3, and 5 h AHP-treated SCF was effective in reducing the glycemic potency than 0.5 h AHP-treated SCF, but not significantly different from the untreated SCF. Overall, this study aims to valorize biomass as AHP is commonly applied to bagasse to produce value-added chemicals and fuels.

Influence of blend proportion and baking conditions on the quality attributes of wheat, orange-fleshed sweet potato and pumpkin composite flour dough and bread: optimization of processing factors

Orange-fleshed sweet potato (OFSP) and pumpkin fruit are underutilized crops with great potential for the production of high-quality bread with health-enhancing properties. However, the incorporation of nonconventional flour in bread formula may influence the dough and bread quality properties. This study investigated the effect of partial substitution of wheat flour with OFSP (10–50%) and pumpkin flour (10–40%), baking temperature (150–200 °C) and baking time (15–25 min) on the quality properties of the composite dough and bread using response surface methodology (RSM). Dough rheological, bread physical and textural properties were analyzed, modelled and optimized using RSM. Satisfactory regression models were developed for the dough and bread quality attributes (R2 > 0.98). The dough development time, crust redness, hardness, and chewiness values increased while optimum water absorption of dough, specific volume, lightness, springiness, and resilience of bread decreased significantly (p < 0.05) with increasing incorporation of OFSP and pumpkin flour in the bread formula. Additionally, the specific volume, crust redness, crumb hardness, and chewiness of the composite bread increased significantly (p < 0.05) with increasing baking temperature from 150 to 180 °C but reduced at higher baking temperatures (≥ 190 °C). The staling rate declined with increased OFSP and pumpkin flour whereas increasing the baking temperature and time increased the bread staling rate. The optimized formula for the composite bread was 78.5% wheat flour, 11.5% OFSP flour, 10.0% pumpkin flour, and baking conditions of 160 °C for 20 min. The result of the study has potential applications in the bakery industry for the development of functional bread.

Graphical Abstract

Empirical and Theoretical Bases of Good Steamed Bread Production

Chinese steamed bread (CSB) is a main staple food in China, accounting for 40% of wheat flour usage in China. Due to its health benefits, CSB is gaining popularity across the world. In this review, the effects of gluten proteins (particularly glutenins and gliadins) on the quality of CSB are summarized from the literature. Requirements of appropriate rheological parameters in different studies are compared and discussed. Along with the increasing demand for frozen storage food, there are obvious increases in the research on the dynamics of gluten proteins in frozen dough. This review also summarizes the factors influencing the deterioration of CSB dough quality during frozen storage as well as effective measures to mitigate the negative effects.

Addition of Amaranth Flour of Different Particle Sizes at Established Doses in Wheat Flour to Achieve a Nutritional Improved Wheat Bread

Amaranth is an underutilized pseudocereal that can be used to supplement wheat flour (WF) in order to improve the nutritional quality of bread. Bread digestibility is impacted by particle size which produces different nutritional properties. This research aims to evaluate the baking characteristics of optimal wheat−amaranth composite flour for each studied amaranth flour (AF) particle size at doses previously established based on an optimization process and to characterize from a physical, textural, nutritional, and sensorial point of view the obtained bread. The results revealed that the optimal wheat−amaranth composite flour with medium and small particle size, respectively showed a slightly lower α-amylase activity, while dough development time was significantly higher compared to the WF. A significant (p < 0.05) decrease was observed in the elasticity, deformation energy, and dynamic rheological parameters of the optimal composite dough for all the particle sizes, whereas fermentation parameters showed higher values compared to the control, indicating the ability of the gluten structure in large, medium, and small particle sizes of AF to hold the gas and to expand without collapsing. The physical, textural, and especially nutritional characteristics of the optimal WF-AF bread were enhanced. The sensory evaluation results revealed high scores (8.70) for the acceptability of optimal bread with a medium particle size as compared to wheat bread (8.25). The protein and ash content of the optimal breads with large, medium, and small AF particle sizes, respectively, increased significantly, from 8.92 to 10.58%, and 0.82 to 0.99%, respectively, relative to the wheat flour bread (8.35% and 0.72%, respectively). The mineral content was up to two times higher in the optimal breads compared to wheat flour bread. The findings generated from this study are helpful in bakery industry for designing products with enhanced nutritional properties and for introducing new products to the market.

In vitro digestion characteristics of cereal protein concentrates as assessed using a pepsin-pancreatin digestion model

An alkaline extraction method has been used in many studies to extract total protein from cereal samples. Wheat bran protein concentrate (WBPC), oat bran protein concentrate (OBPC), and barley protein concentrate (BPC) were prepared by alkaline extraction and isoelectric precipitation to study their functional and nutritional properties. The three protein concentrates were hydrolysed by an in vitro pepsin-pancreatin digestion model. Their digestibility (%) and degree of hydrolysis (DH%) were evaluated, and SDS-PAGE electrophoresis was used to illustrate the protein and peptides patterns. The change of the particle sizes and the release of the essential amino acids was followed during the digestion process. The in vitro digestibility of WBPC, OBPC and BPC was 87.4%, 96.1% and 76.9%, respectively. The DH% of protein concentrates were between 50 and 60%. The change of the particle size distribution values Dv(50) was assumed to be related to protein aggregations during the digestion. The protein fractions were identified and the degradation during the digestion and were analysed by SDS-PAGE; the gels of WBPC and OBPC digestion showed virtually complete degradation whereas the intensive bands of undigested protein were presented for BPC. The generation of the free amino acids and short chain peptides were significantly higher at the end of the intestinal digestion compared to the stages of before and after gastric digestion. Higher content of the deficient amino acids such as lysine and threonine were found comparing to the level of deficient amino acids in cereal grains but does not meet the daily recommended intake.

A novel neutral thermophilic β-mannanase from Malbranchea cinnamomea for controllable production of partially hydrolyzed konjac powder

Partially hydrolyzed konjac powder (PHKP) can be used to increase the daily intake of dietary fibers of consumers. To produce PHKP by enzymatic hydrolysis, a novel β-mannanase gene (McMan5B) from Malbranchea cinnamomea was expressed in Pichia pastoris. It showed a low identity of less than 52% with other GH family 5 β-mannanases. Through high cell density fermentation, the highest β-mannanase activity of 42200 U mL^-1 was obtained. McMan5B showed the maximal activity at pH 7.5 and 75 °C, respectively. It exhibited excellent pH stability and thermostability. Due to the different residues (Phe214, Pro253, and His328) in catalytic groove and the change of β2-α2 loop, McMan5B showed unique hydrolysis property as compared to other β-mannanases. The enzyme was employed to hydrolyze konjac powder for controllable production of PHKP with a weight-average molecular weight of 22000 Da (average degree of polymerization 136). Furthermore, the influence of PHKP (1.0%-4.0%) on the qualities of steamed bread was evaluated. The steamed bread adding 3.0% PHKP had the maximum specific volume and the minimum hardness, which showed 11.0% increment and 25.4% decrement as compared to the control, respectively. Thus, a suitable β-mannanase for PHKP controllable production and a fiber supplement for steamed bread preparation were provided in this study. KEY POINTS: • A novel β-mannanase gene (McMan5B) was cloned from Malbranchea cinnamomea and expressed in Pichia pastoris at high level. • McMan5B hydrolyzed konjac powder to yield partially hydrolyzed konjac powder (PHKP) instead of manno-oligosaccharides. • PHKP showed more positive effect on the quality of steamed bread than many other dietary fibers including konjac powder.

Evolutionary Wheat Populations in High-Quality Breadmaking as a Tool to Preserve Agri-Food Biodiversity

Plant biodiversity preservation is one of the most important priorities of today’s agriculture. Wheat (Triticum spp. L.) is widely cultivated worldwide, mostly under a conventional and monovarietal farming method, leading to progressive biodiversity erosion. On the contrary, the evolutionary population (EP) cultivation technique is characterized by mixing and sowing together as many wheat genotypes as possible to allow the crop to genetically adapt over the years in relation to specific pedoclimatic conditions. The objective of this study was to assess the nutritional, chemical and sensory qualities of three different breads obtained using different organic EP flours, produced following a traditional sourdough process and compared to a commercial wheat cultivar bread. Technological parameters, B-complex vitamins, microelements, dietary fibre and phenolic acids were determined in raw materials and final products. Flours obtained by EPs showed similar characteristics to the commercial wheat cultivar flour. However, significant differences on grain technological quality were found. The breads were comparable with respect to chemical and nutritional qualities. Overall, the sensory panellists rated the tasted breads positively assigning the highest score to those produced with EPs flours (6.75–7.02) as compared to commercial wheat cultivar-produced bread (cv. Bologna, 6.36).

The Characteristics of Steamed Bread from Reconstituted Whole Wheat Flour (WWF) of Different Hard Wheat Classes with Different Bran Particle Size Distributions

The purpose of this study was to investigate the effects of reconstituted whole wheat flour (WWF) particle size on flour characteristics and northern-type steamed bread (NTSB) quality. In this study, hard white (HW), hard red winter (HRW), and hard red spring (HRS) wheat classes, and four different bran particle size distributions [D(50) values of 53 μm, 74 μm, 105 μm, and 125 μm] were blended at a ratio of 85% refined flour + 15% bran to create reconstituted WWF and make reconstituted WWF NTSB. Farinograph water absorption and water solvent retention capacity (SRC) increased as bran particle size decreased. Flour and dough strength tests such as lactic acid SRC and Farinograph and Mixolab development time and stability did not show any clear trends with bran particle size. HRW WWF tended to be the exception as Farinograph development time and stability generally increased as particle size increased. Resistance to extension increased as bran particle size decreased for HRW WWF and increased as particle size increased for HW and HRS. These differences in WWF dough rheology trends were likely due to differences in gluten characteristics between the classes. The results showed that larger particle sizes (105 μm and 125 μm) were more conducive to achieving desirable whole wheat NTSB specific volume, color, and texture.