Improving storage property of wheat bran by steam explosion

The Principle of Steam Explosion Technology and Its Application in Food Processing By-Products

Steam explosion technology is an emerging pretreatment method that has shown great promise for food processing due to its ability to efficiently destroy the natural barrier structure of materials. This narrative review summarizes the principle of steam explosion technology, its similarities and differences with traditional screw extrusion technology, and the factors that affect the technology. In addition, we reviewed the applications in food processing by-products in recent years. The results of the current study indicate that moderate steam explosion treatment can improve the quality and extraction rate of the target products. Finally, we provided an outlook on the development of steam explosion technology with a reference for a wider application of this technology in the food processing field.

Effects of Co-Modification by Extrusion and Enzymatic Hydrolysis on Physicochemical Properties of Black Wheat Bran and Its Prebiotic Potential

Black wheat bran (BWB) is an important source of dietary fiber (DF) and phenolic compounds and has stronger nutritional advantages than ordinary WB. However, the low content of soluble dietary fiber (SDF) negatively influences its physicochemical properties and nutritive functions. To obtain a higher content of SDF in BWB, we evaluated the impact of co-modification by extrusion and enzymes (cellulase, xylanase, high-temperature α-amylase, and acid protease) on water extractable arabinoxylan (WEAX) in BWB. An optimized co-modification method was obtained through single-factor and orthogonal experiments. The prebiotic potential of co-modified BWB was also evaluated using pooled fecal microbiota from young, healthy volunteers. The commonly investigated inulin served as a positive control. After co-modification, WEAX content was dramatically increased from 0.31 g/100 g to 3.03 g/100 g (p < 0.05). The water holding capacity, oil holding capacity, and cholesterol adsorption capacity (pH = 2.0 and pH = 7.0) of BWB were increased by 100%, 71%, 131%, and 133%, respectively (p < 0.05). Scanning electron microscopy demonstrated a looser and more porous microstructure for co-modified BWB granules. Through in vitro anerobic fermentation, co-modified BWB achieved a higher content of Bifidobacterium and Lactobacillus than inulin fermentation. In addition, co-modified BWB induced the highest butyric acid production, indicating high potential as prebiotics. The results may contribute to improving technologies for developing high-fiber-content cereal products.

Effects of steam explosion on the nutritional and functional properties of black-grained wheat bran and its application

BACKGROUND

In recent years, an increasing interest in healthy functional foods has been documented among health-conscious consumers. Steam explosion (SE)-treated black-grained wheat (BGW) bran was explored for the development of chiffon cakes with high nutritional and functional value.

RESULTS

The content of crude fat and total starch decreased with increasing SE pressure, whereas water-holding capacity and antioxidant activity increased, suggesting SE at 0.6-1.0 MPa could be an effective technique for enhancing the nutritional and functional properties of wheat bran. The protein, iron, zinc, manganese, selenium, and soluble dietary fiber contents, the water-holding, oil-binding, swelling, cholesterol binding, and cation-exchange capacities, and antioxidant activity of SE BGW bran were better than those of SE white-grained wheat bran. The addition of SE bran (0.8 MPa) to flour significantly decreased the peak viscosity, final viscosity, and setback and increased the pasting temperature. The effect of SE bran on the pasting properties of low-gluten and medium-gluten flour was stronger than that of high-gluten flour. SE BGW bran altered the physicochemical properties of chiffon cakes. When 6% SE BGW bran (0.8 MPa) was added, chiffon cakes exhibited good specific volume, hardness, chewiness, and other sensory qualities.

CONCLUSIONS

These results indicate that SE at 0.6-1.0 MPa is an effective technique for enhancing the nutritional and functional properties of wheat bran. SE BGW bran can be alternatives to food materials for developing health functional cereal-based products. © 2022 Society of Chemical Industry.

Physical properties, antioxidant capacity, and starch digestibility of cookies enriched with steam-exploded wheat bran

Wheat bran-based food is rich in bioactive compounds, and steam explosion enhances the nutritional properties of wheat bran. This study examined the potential utilization of steam-exploded wheat bran (SWB) in cookie formulation. The influence of steam explosion on the chemical compounds in wheat bran and the effects of SWB on the physical properties, antioxidant capacity, and starch digestibility of cookies were investigated. The results showed that steam explosion facilitated the release of reducing sugar, flavonoids, phenolic substances, and amino acid nitrogen in wheat bran, thereby improving its nutritional properties. The reduction of sugar, total flavonoids, total phenolics, and amino acid nitrogen contents of wheat bran after steam explosion increased by 34.22, 183.02, 284.09, and 93.39%, respectively, compared with those of native wheat bran. Substitution of SWB for wheat flour mainly induced higher water, sodium carbonate, and sucrose solvent retention capacities, which were positively related to the spread ratio and hardness of cookies. The cookies with more SWB substitution (30-50%) expressed a higher spread ratio and harder texture than the others. The substitution of SWB caused changes in the antioxidant properties of cookies, which were related to the phenolic content. The cookies with SWB showed a higher DPPH radical scavenging activity (16.30-30.93%) than that of the control (14.74%). SWB might form a matrix barrier to hinder starch digestion, thus reducing the digestibility of cookies. The cookies enriched with 30-50% of the SWB exhibited greater physical properties and antioxidant capacity but lower starch digestibility than those of other cookies. The results will contribute to expanding the application range and improving the quality of bran-rich flour products.

Correlation of steam explosion severity with morphological and physicochemical characterization of soybean meal

Steam explosion, a novel effective technology for cereal modification, integrates high-temperature autohydrolysis and structural disruption, which can significantly influence the morphological and physicochemical characterization of the feedstocks. The deep knowledge of the structural changes that are brought about by the treatment severity is connected with the technological demands to improve the processing efficiency and to increase the industrial application of the feedstocks by steam explosion. In this study, the changes in morphological and physicochemical properties of soybean meal induced by steam explosion were investigated. The correlation of steam explosion severity with soybean meal's final quality was also analyzed. The results showed that steam explosion effectively increased the fractal dimension from 1.6553 to 1.8871, the glycinin content from 151.38 to 334.94 mg/g, and the 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging activity from 28.69 to 63.78%. The gray value, color (L* and a* values), and the total phenol and polysaccharide contents of soybean meal were reduced with greater steam explosion severity. Steam explosion severity had a remarkable positive correlation with the fractal dimension and DPPH radical scavenging activity. However, steam explosion severity had no significant correlation with the textural and adsorption properties of the soybean meal. This study focused on the morphological and physicochemical property changes of the soybean meal during a steam explosion process, which could guide the application of steam explosion in food systems.

Principle and Application of Steam Explosion Technology in Modification of Food Fiber

Steam explosion is a widely used hydrothermal pretreatment method, also known as autohydrolysis, which has become a popular pretreatment method due to its lower energy consumption and lower chemical usage. In this review, we summarized the technical principle of steam explosion, and its definition, modification and application in dietary fiber, which have been explored by researchers in recent years. The principle and application of steam explosion technology in the modification of food dietary fiber were analyzed. The change in dietary fiber structure; physical, chemical, and functional characteristics; the advantages and disadvantages of the method; and future development trends were discussed, with the aim to strengthen the economic value and utilization of plants with high dietary fiber content and their byproducts.

Effect of steam explosion on nutritional components, physicochemical and rheological properties of brown rice powder

Brown rice powder is underutilized mainly due to its lower starch digestibility and poor processing performance. The present study investigated the potential of steam explosion on the improvement of nutritional and physicochemical characteristic in brown rice powder and rheological property of paste. Compared with native brown rice powder, steam explosion at 0.5 MPa for 7 min increased the water-extractable arabinoxylans (5.77%), reducing sugar content (21.04%), and iodine blue value (30.38%), which indicated steam explosion that destroyed the intact cells of brown rice. Later the crystalline structure of brown rice powder was destroyed into an amorphous structure by steam explosion. Steam explosion enhanced the degree of gelatinization (4.76~351.85%) and solvent retention capacity (SRC) of brown rice powder, compared with native sample. The effect on the intact cells and starch structure of brown rice caused the starch digestibility enhancement remarkable. Viscoelastic profiles confirmed that steam explosion weakened the paste strength and elasticity corresponded with hardness and cohesiveness by increasing the loss factor (tanδ). This work provided important information for brown rice powder modified by steam explosion (0.5 MPa, 7 min) with good nutritional property (nutrients and digestibility) and processability (SRC, textural, and rheological property). Steam exploded brown rice powder (0.5 MPa, 7 min) could serve as a potential ingredient widely used in food products.

Improving bioaccessibility and physicochemical property of blue-grained wholemeal flour by steam explosion

Whole grain contains many health-promoting ingredients, but due to its poor bioaccessibility and processibility, it is not widely accepted by consumers. The steam explosion was exploited to modify the nutritional bioaccessibility and the physicochemical properties of wholemeal flour in this study. In vitro starch digestibility, in vitro protein digestibility of wholemeal flour, total flavonoids content, and total phenolics content of digestive juice were used to evaluate the bioaccessibility, and a significant variation (p < 0.05) was noted. Results showed that steam explosion enhanced the gastric protein digestibility ranged from 5.67 to 6.92% and the intestinal protein digestibility ranged from 16.77 to 49.12%. Steam-exploded wholemeal flour (0.5 MPa, 5 min) had the highest protein digestibility and rapidly digestible starch content. Compared with native flour, steam explosion (0.5 MPa, 5 min) contributed to a 0.72-fold and 0.33-fold increment of total flavonoids content and total phenolics content in digestible juice. Chemical changes of wholemeal flour, induced by steam explosion, caused the changes in the solvent retention capacity, rheological property of wholemeal flour, and altered the falling number (and liquefaction number). An increasing tendency to solid-like behavior and the gel strength of wholemeal flour was significantly enhanced by the steam explosion at 0.5 MPa for 5 min, while the gluten was not weakened. This study indicated that steam-exploded wholemeal flour (0.5 MPa, 5 min) could serve as a potential ingredient with the noticeable bioaccessibility and physicochemical properties in cereal products.

Improving Antioxidative and Antiproliferative Properties Through the Release of Bioactive Compounds From Eucommia ulmoides Oliver Bark by Steam Explosion

Eucommia ulmoides Oliver bark is a potential medicinal plant-based feedstock for bioactive products and possesses the effective functions of antioxidant and antitumor. Network pharmacology was employed to reveal the oxidative and free radical damage and cancer-related potential compounds of Eucommia ulmoides Oliver in this study. The result showed that quercetin might be the key compound to resist these two types of diseases. Then, the effect of steam explosion on the release of bioactive compounds and the antioxidative and antiproliferative properties of the extract from Eucommia ulmoides Oliver bark were investigated. Results showed that steam explosion at 0.7 MPa for 30 min significantly enhanced the total phenolic, total flavonoids, and quercetin content of Eucommia ulmoides Oliver bark. Reducing power and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging activity of the steam-exploded extracting solution were 1.72 and 2.76 times of native. The antiproliferative activity to CT26 and HepG2 of the extract from steam-exploded Eucommia ulmoides Oliver bark (SEU) was higher than those of native-exploded Eucommia ulmoides Oliver bark (NEU). All these results suggested that steam explosion could be applied to release the bioactive compounds, thus enhanced the antioxidative and antiproliferative activities of medicinal and edible plant-based sources.

Effect of Steam Explosion on Structural Characteristics of β-Conglycinin and Morphology, Chemical Compositions of Soybean Meal

In this study, steam explosion was applied as a means to degrade β-conglycinin. We investigated changes in morphology, the chemical composition of soybean meal, and the structural characteristics of β-conglycinin. The results showed that steam explosion at 0.7 MPa for 8 min could effectively decrease the β-conglycinin content of soybean meal while the histamine content was not increased. The structural characteristics of soybean meal proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), and X-ray diffraction (XRD). Steam explosion caused the degradation of high weight proteins and reduced the band density of α', α, and β subunits in β-conglycinin. The micro-surface of soybean meal seemed to be in the cracked or puffed stage and the color became brown or dark after steam explosion. Steam explosion facilitated the dissolution of water-extractable arabinoxylans, which are 4.81 fold higher than that of native soybean meal. Phytic acid was exposed to the hydrothermal environment of the steam explosion process and consequently degraded by 12.95-24.69%. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of soybean meal extract was gradually increased from 20.70 to 33.71% with the rising of treated pressure from 0.3 to 0.7 MPa, which was 1.11-1.81 fold of native extract. The steam explosion may be a new modification technology that could decrease antigenicity, and steam-exploded soybean meal (0.7 MPa, 8 min) with lower β-conglycinin and phytic acid content that could be widely used in food products.

Arabinoxylans as Functional Food Ingredients: A Review

The health benefits of fibre consumption are sound, but a more compressive understanding of the individual effects of different fibres is still needed. Arabinoxylan is a complex fibre that provides a wide range of health benefits strongly regulated by its chemical structure. Arabinoxylans can be found in various grains, such as wheat, barley, or corn. This review addresses the influence of the source of origin and extraction process on arabinoxylan structure. The health benefits related to short-chain fatty acid production, microbiota regulation, antioxidant capacity, and blood glucose response control are discussed and correlated to the arabinoxylan's structure. However, most studies do not investigate the effect of AX as a pure ingredient on food systems, but as fibres containing AXs (such as bran). Therefore, AX's benefit for human health deserves further investigation. The relationship between arabinoxylan structure and its physicochemical influence on cereal products (pasta, cookies, cakes, bread, and beer) is also discussed. A strong correlation between arabinoxylan's structural properties (degree of branching, solubility, and molecular mass) and its functionalities in food systems can be observed. There is a need for further studies that address the health implications behind the consumption of arabinoxylan-rich products. Indeed, the food matrix may influence the effects of arabinoxylans in the gastrointestinal tract and determine which specific arabinoxylans can be included in cereal and non-cereal-based food products without being detrimental for product quality.

Effects of konjac glucomannan on the long-term retrogradation and shelf life of boiled wheat noodles

BACKGROUND

Starch retrogradation and moisture migration of boiled wheat noodles (BWNs) result in quality deterioration and short shelf life. The objective of this research was to investigate whether konjac glucomannan (KGM) could improve the quality of BWNs and further establish the shelf-life prediction model.

RESULTS

The moisture distribution, recrystallization, and thermal properties of BWNs during refrigerated or ambient temperature storage were determined. Low-field nuclear magnetic resonance data showed that KGM addition induced left-shifts of T₂₁ and T₂₂ values, indicating that KGM limited the mobility of bound and immobile water among noodle matrices. X-ray diffraction spectra revealed that KGM did not change the crystal patterns of BWNs but could inhibit the starch recrystallization after refrigerated storage. The T_p and ΔH values of retrograded samples notably (P < 0.05) decreased with the increase of KGM addition, suggesting the hinderance of starch retrogradation behavior by KGM. The shelf life of BWNs was predicted by accelerated storage test combined with the Arrhenius equation. The present data displayed that the predicted shelf life of vacuum-packed and sterilized BWNs with 10 g kg^-1 KGM at 25 °C was 733 days, 2.4-fold that of the control group.

CONCLUSION

BWNs with KGM addition could inhibit starch retrogradation and improve the storage stability, consequently promoting noodle quality. © 2021 Society of Chemical Industry.

Severity factor kinetic model as a strategic parameter of hydrothermal processing (steam explosion and liquid hot water) for biomass fractionation under biorefinery concept

Hydrothermal processes are an attractive clean technology and cost-effective engineering platform for biorefineries based in the conversion of biomass to biofuels and high-value bioproducts under the basis of sustainability and circular bioeconomy. The deep and detailed knowledge of the structural changes by the severity of biomasses hydrothermal fractionation is scientifically and technological needed in order to improve processes effectiveness, reactors designs, and industrial application of the multi-scale target compounds obtained by steam explosion and liquid hot water systems. The concept of the severity factor [log₁₀ (R_o)] established>30 years ago, continues to be a useful index that can provide a simple descriptor of the relationship between the operational conditions for biomass fractionation in second generation of biorefineries. This review develops a deep explanation of the hydrothermal severity factor based in lignocellulosic biomass fractionation with emphasis in research advances, pretreatment operations and the applications of severity factor kinetic model.

Wheat Bran Modifications for Enhanced Nutrition and Functionality in Selected Food Products

The established use of wheat bran (WB) as a food ingredient is related to the nutritional components locked in its dietary fibre. Concurrently, the technological impairment it poses has impeded its use in product formulations. For over two decades, several modifications have been investigated to combat this problem. Ninety-three (93) studies (review and original research) published in English between January 1997 and April 2021 reporting WB modifications for improved nutritional, structural, and functional properties and prospective utilisation in food formulations were included in this paper. The modification methods include mechanical (milling), bioprocessing (enzymatic hydrolysis and fermentation with yeasts and bacteria), and thermal (dry heat, extrusion, autoclaving), treatments. This review condenses the current knowledge on the single and combined impact of various WB pre-treatments on its antioxidant profile, fibre solubilisation, hydration properties, microstructure, chemical properties, and technological properties. The use of modified WB in gluten-free, baked, and other food products was reviewed and possible gaps for future research are proposed. The application of modified WB will have broader application prospects in food formulations.

Effect of superheated steam treatment on the lipid stability of whole wheat flour

This study aimed to investigate the effect of superheated steam treatment (SST) on lipid stability of whole wheat flour (WWF) during storage. After SST, the lipase and peroxidase of WWF were inactivated, and lipoxygenase activity was lower than 5% of its initial value. The total tocopherols decreased slightly in all SST groups, especially it only decreased by 1.1% at 190 °C for 5 s. Furthermore, the increase of fatty acid value in the control group was over 100-fold than that of the SST groups during storage. The unsaturated fatty acids and total tocopherols in WWF decreased gradually, but the decrease was alleviated by SST at 190 °C for 5 s. After storage, the relative content of hexanal and 2-pentylfuran in the SST groups were 4 and 0.3-fold than those in the control group, respectively. Thus, SST may be a potential approach to stabilise the quality of WWF.