Properties of soluble dietary fiber-polysaccharide from papaya peel obtained through alkaline or ultrasound-assisted alkaline extraction

In vivo absorption, in vitro digestion, and fecal fermentation properties of non-starch polysaccharides from Chinese chestnut kernels and their effects on human gut microbiota

Non-starch polysaccharides are major bioactive components in chestnuts, and can serve as water-soluble polysaccharides with potential prebiotic properties. This study aims to establish an in vitro digestion and fermentation model to reveal the digestive and fermentative characteristics of Non-starch polysaccharides from chestnut kernels (NSPCK). The results indicated that under simulated digestion, NSPCK was partially digested in gastric juice but remained significantly undigested in saliva and intestinal juice, demonstrating considerable resilience against hydrolysis. After digestion, NSPCK still exhibited stable rough, lamellar, and porous structure and maintained strong antioxidant capacity. Animal experiments revealed positive effects of NSPCK on blood lipid level, and colon tissue of mice. Moreover, NSPCK enhanced the accumulation of short-chain fatty acids during fermentation, particularly acetic acid, propionic acid, and butyric acid. Furthermore, NSPCK intervention increased the abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium, and at the same time reduced that of harmful bacteria such as Enterococcus.

Effects of airflow superfine pulverization on the structure, functional properties, and flavor quality of wheat bran

BACKGROUND

Wheat bran (WB) is a byproduct of refined wheat flour production with poor edible taste and low economic value. Herein, the WB was micronized via airflow superfine pulverization (ASP), and the effects of the ASP conditions on its particle size, nutritive compositions, whiteness, hydration characteristics, moisture distribution, microstructure, cation exchange capacity, volatile flavor components, and other characteristics were investigated.

RESULTS

Reducing the rotational speed of the ASP screw and increasing the number of pulverizations significantly decreased the median particle size Dx(50) of WB to a minimum of 12.97 ± 0.19 μm (P < 0.05), increased the soluble dietary fiber content from 55.05 ± 2.94 to 106.86 ± 1.60 mg g-1, and improved the whiteness and water solubility index. In addition, the water holding capacity and oil holding capacity were significantly reduced (P < 0.05), while the cation exchange and swelling capacities first increased and then decreased. Up to about 70% of water in WB exists as bound water. As the Dx(50) of WB decreased, the content of bound and immobile water increased, while the free water decreased from 14.37 ± 1.21% to 7.59 ± 1.03%. Furthermore, WB was micronized and the particles became smaller and more evenly distributed. Using gas chromatography-ion mobility spectrometry, a total of 37 volatile compounds in micronized WB (including 10 aldehydes, 9 esters, 7 alcohols, and several acids, furans, ethers, aldehydes, esters, and alcohols) were identified as the main volatile compounds of WB.

CONCLUSION

Collectively, ASP improved the physicochemical properties of WB. This study provides theoretical references for the use of ASP to improve the utilization and edibility of WB. © 2024 Society of Chemical Industry.

Valorizing date seeds through ultrasonication to enhance quality attributes of dough and biscuit, Part-1: Effects on dough rheology and physical properties of biscuits

In the present study, non-conventional and green technology (ultrasonication) was utilized to recover bioactive compounds from the small, medium and large sized defatted date seed powder (DDSP) particles. Bioactive compounds recovered from DDSP and the remaining fiber-rich residue were incorporated as functional ingredient in the biscuit dough to enhance the functionality and the quality characteristics of the dough and biscuit. The polyphenolic extract and 2.5 %, 5 % and 7.5 % substitution levels of fiber-rich extraction residue were incorporated in formulations followed by investigating the effect on rheological, physical and microstructural properties of dough and biscuit. Loss and storage moduli, G'' and G', respectively, of dough increased with decreasing particle size and increasing substitution level while tan δ decreased with increasing substitution level of fiber-rich extraction residue. The smallest particles at 7.5 % substitution level resulted in the lowest creep strain value in dough. Hardness of the dough and biscuit increased with decreasing particle size and increasing substitution level of the residue. The 7.5 % substitution level of the smallest particle size resulted in the darkest dough and biscuit. Spread ratio and diameter of the biscuit decreased with increasing substitution level of the residue. The smallest diameter of 50.61 mm and spread ratio of 8.36 was observed in the biscuits substituted with the largest particle size with 7.5 % substitution level. Microstructural images of dough and biscuit revealed that the continuity of the gluten network was disrupted by the incorporation of the fiber-rich extraction residue. This study provided valuable insights into extracting bioactive components from date by-products using green ultrasonication technique and utilizing such compounds to improve functional attributes of bakery products, as a sustainable approach for valorizing date by-products.

Potential prebiotic effects of soy by-products as novel dietary fibre: Structure, function, in vitro simulation of digestion and fermentation properties

This study aimed to prepare soybean dregs dietary fibre (DF) using physically assisted chemical (KHMSO) modification and study its structure, function and vitro simulation experiments. The soluble dietary fibre (SDF) content in KHMSO increased and insoluble dietary fibre (IDF) content decreased. The modified DF surface becomes irregular and rough, and the results of XPS fitting indicated that the DF structure had different peak-splitting groups. The KHMSO-treated group had the lowest digestion rate in gastric fluid and the highest digestibility in intestine fluid. The OD600 of fecal cultures was increased to 0.915, and the increased abundance of microbiota was associated with the metabolism of SCFAs, such as Lachnospiraceae, as well as the higher n-butyric acid in the KHMSO-treated group compared to the other groups and lower than the inulin, suggesting KHMSO might enhance the production of functional foods aimed at promoting intestinal health.

A sequential approach of alkali enzymatic extraction of dietary fiber from rice bran: Effects on structural, thermal, crystalline properties, and food application

Rice bran is abundant in dietary fiber and is often referred to as the seventh nutrient, recognized for its numerous health benefits. The objective of the current study is to investigate the extraction of both soluble and insoluble dietary fiber from defatted rice bran (DRB) using an alkali-enzymatic treatment through response surface methodology. The independent variables like substrate percentage (5-30 %), enzyme concentration (1-50 µL/g), and treatment time (2-12 h) and dependent variables were the yield of soluble and insoluble DF. The highest extraction yield was observed with alkali enzyme concentration (50 µL/g) treatment, resulting in 2 % SDF and 59.5 % IDF at 24 h of extraction. The results indicate that cellulase-AC enzyme aids in the hydrolysis of higher polysaccharides, leading to structural alterations in DRB and an increase in DF yield. Furthermore, the disruption of intra-molecular hydrogen bonding between oligosaccharides and the starch matrix helps to increase in DF yield, was also confirmed through FTIR and SEM. The extracted DF soluble and insoluble was then used to develop rice porridge. Sensory evaluation using fuzzy logic analysis reported the highest scores for samples containing 0.5 % insoluble DF and 1.25 % soluble DF.

Enhancing mechanical and water barrier properties of starch film using chia mucilage

Biodegradable packaging materials are increasingly being investigated due to rising concerns about food safety and environmental conservation. This study examines the incorporation of chia mucilage (CM) into starch-based films using the casting method, aiming to understand its effects on the structure and functionality of the films. CM, an anionic heteropolysaccharide, is hypothesized to enhance the mechanical and barrier properties of the films through polymer interactions and hydrogen bonding. Our findings confirm that CM incorporation results in films with uniformly smooth surfaces, indicating high compatibility and homogeneity within the starch matrix. Notably, CM improves film transparency and crystallinity. Mechanical assessments show a remarkable elevation in tensile strength, soaring from 5.21 MPa to 12.38 MPa, while elongation at break decreases from 61.73 % to 31.42 %, indicating a trade-off between strength and flexibility. Additionally, water solubility decreases from 57.97 % to 41.40 %, and water vapor permeability is reduced by 30 % with CM loading. These results highlight the role of CM in facilitating the formation of a dense, interconnected polymeric network within the starch matrix. Given the soluble dietary fiber nature of CM, the CS/CM (corn starch/chia mucilage) blended films are expected to be safe for food packaging and applicable as edible films with health benefits.

Effects of Different Extraction Methods on the Structural and Functional Properties of Soluble Dietary Fibre from Sweet Potatoes

In this study, hot water treatment (WT), ultrasonic treatment (UT), ultrasonic-sodium hydroxide treatment (UST), ultrasonic-enzyme treatment (UET), and ultrasonic-microwave treatment (UMT) were used to treat sweet potatoes. The structural, physicochemical, and functional properties of the extracted soluble dietary fibres (SDFs) were named WT-SDF, UT-SDF, UST-SDF, UET-SDF, and UMT-SDF, respectively. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal properties, and Brunauer-Emmett-Teller (BET) analysis were employed. The structural results indicated that the UST-SDF exhibited the best thermal stability, highest crystallinity, and maximum specific surface area. Moreover, compared to hot water extraction, ultrasonic extraction, or ultrasonic extraction in combination with other methods, enhanced the physicochemical and functional properties of the SDF, including extraction yield, water-holding capacity (WHC), oil-holding capacity (OHC), glucose adsorption capacity (GAC), glucose dialysis retardation index (GDRI), sodium cholate adsorption capacity (SCAC), cholesterol adsorption capacity (CAC), nitrite ion adsorption capacity (NIAC), and antioxidant properties. Specifically, the UST-SDF and UMT-SDF showed better extraction yield, WHC, OHC, GAC, CAC, SCAC, and NIAC values than the other samples. In summary, these results indicate that UST and UMT could be applied as ideal extraction methods for sweet potato SDF and that UST-SDF and UMT-SDF show enormous potential for use in the functional food industry.

Investigating the physicochemical characteristics and importance of insoluble dietary fiber extracted from legumes: An in-depth study on its biological functions

Legumes are widely appreciated for their abundant reserves of insoluble dietary fiber, which are characterized by their high fiber content and diverse bioactive compounds. Insoluble dietary fiber in leguminous crops is primarily localized in the structural cell walls and outer integument and exhibits strong hydrophilic properties that enable water absorption and volumetric expansion, resulting in increased food bulk and viscosity. This contributes to enhanced satiety and accelerated gastrointestinal transit. The benefits of legume insoluble dietary fiber extend to its notable antioxidant, anti-inflammatory, and anti-cancer properties, as well as its ability to modulate the composition of the intestinal microbiota, promoting the growth of beneficial bacteria while suppressing the proliferation of harmful pathogens, thereby promoting optimal intestinal health. It is highly valued as a valuable thickening agent, stabilizer, and emulsifier, contributing to the texture and stability of a wide range of food products.

Extraction of Heracleum dissectum soluble dietary fiber by different methods: Structure and antioxidant properties

Heracleum dissectum is rich in nutrients, but there is little research on its soluble dietary fiber (SDF). In this study, SDF from H. dissectum was extracted by enzyme extraction (E-SDF), enzyme chemical extraction (EC-SDF), and fermentation extraction (F-SDF). The composition, molecular weight (Mw), structural characterization, and antioxidant activity of SDF extracted by the three methods were compared. This study showed that different extraction methods lead to differences in their structure. The Mw results showed that F-SDF had the largest Mw, the structure of SDF could be destroyed by enzymatic hydrolysis, and large molecules could be converted into small molecules. The monosaccharide composition analysis showed that the main sugars of E-SDF, EC-SDF, and F-SDF were galacturonic acid and galactose, and the main components of the three SDF samples were hemicellulose hydrolyzed pectin and soluble polysaccharide. Notably, E-SDF had the greatest antioxidant effect at the same concentration. In summary, different extraction methods can affect the structure and antioxidant capacity of H. dissectum SDF, among which E-SDF has potential as a functional food ingredient.

Advances in the novel and green-assisted techniques for extraction of bioactive compounds from millets: A comprehensive review

Millets are rich in nutritional and bioactive compounds, including polyphenols and flavonoids, and have the potential to combat malnutrition and various diseases. However, extracting these bioactive compounds can be challenging, as conventional methods are energy-intensive and can lead to thermal degradation. Green-assisted techniques have emerged as promising methods for sustainable and efficient extraction. This review explores recent trends in employing green-assisted techniques for extracting bioactive compounds from millets, and potential applications in the food and pharmaceutical industries. The objective is to evaluate and comprehend the parameters involved in different extraction methods, including energy efficiency, extraction yield, and the preservation of compound quality. The potential synergies achieved by integrating multiple extraction methods, and optimizing extraction efficiency for millet applications are also discussed. Among several, Ultrasound and Microwave-assisted extraction stand out for their rapidity, although there is a need for further research in the context of minor millets. Enzyme-assisted extraction, with its low energy input and ability to handle complex matrices, holds significant potential. Pulsed electric field-assisted extraction, despite being a non-thermal approach, requires further optimization for millet-specific applications, are few highlights. The review emphasizes the importance of considering specific compound characteristics, extraction efficiency, purity requirements, and operational costs when selecting an ideal technique. Ongoing research aims to optimize novel extraction processes for millets and their byproducts, offering promising applications in the development of millet-based nutraceutical food products. Therefore, the current study benefits researchers and industries to advance extraction research and develop efficient, sustainable, and scalable techniques to extract bioactive compounds from millets.

Optimization of Composite Enzymatic Extraction, Structural Characterization and Biological Activity of Soluble Dietary Fiber from Akebia trifoliata Peel

In order to reduce the waste of Akebia trifoliata peel and maximize its utilization, in this study, on the basis of a single-factor experiment and the response surface method, the optimum technological conditions for the extraction of soluble dietary fiber from Akebia trifoliata peel with the compound enzyme method were obtained. The chemical composition, physical and chemical properties, structural characterization and biological activity of the purified soluble dietary fiber (AP-SDF) from the Akebia trifoliata peel were analyzed. We discovered that that the optimum yield was 20.87% under the conditions of cellulase addition 600 U/g, enzymolysis time 100 min, solid-liquid ratio 1:24 g/mL and enzymolysis temperature 51 °C. At the same time, AP-SDF was a porous network structure cellulose type I acidic polysaccharose mainly composed of arabinoxylan (36.03%), galacturonic acid (27.40%) and glucose (19.00%), which possessed the structural characteristic peaks of the infrared spectra of polysaccharides and the average molecular weight (Mw) was 95.52 kDa with good uniformity. In addition, the AP-SDF exhibited high oil-holding capacity (15.11 g/g), good water-holding capacity and swelling capacity, a certain antioxidant capacity in vitro, hypoglycemic activity in vitro for α-glucosidase inhibition and hypolipidemic activity in vitro for the binding ability of bile acids and cholesterol. These results will provide a theoretical basis for the development of functional products with antioxidant, hypoglycemic and hypolipidemic effects, which have certain application value in related industries.

Modification of pea dietary fibre by superfine grinding assisted enzymatic modification: Structural, physicochemical, and functional properties

Using the optimal extraction conditions determined by response surface optimisation, the yield of soluble dietary fibre (SDF) modified by superfine grinding combined with enzymatic modification (SE-SDF) was significantly increased from 4.45 % ± 0.21 % (natural pea dietary fibre) to 16.24 % ± 0.09 %. To further analyse the modification mechanism, the effects of three modification methods-superfine grinding (S), enzymatic modification (E), and superfine grinding combined with enzymatic modification (SE)-on the structural, physicochemical, and functional properties of pea SDF were studied. Nuclear magnetic resonance spectroscopy results showed that all four SDFs had α- and β-glycosidic bonds. Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy results showed that the crystal structure of SE-SDF was most severely damaged. The Congo red experimental results showed that none of the four SDFs had a triple-helical structure. Scanning electron microscopy showed that SE-SDF had a looser structure and an obvious honeycomb structure than other SDFs. Thermogravimetric analysis, particle size, and zeta potential results showed that SE-SDF had the highest thermal stability, smallest particle size, and excellent solution stability compared with the other samples. The hydration properties showed that SE-SDF had the best water solubility capacity and water-holding capacity. All three modification methods (S, E, and SE) enhanced the sodium cholate adsorption capacity, cholesterol adsorption capacity, cation exchange capacity, and nitrite ion adsorption capacity of pea SDF. Among them, the SE modification had the greatest effect. This study showed that superfine grinding combined with enzymatic modification can effectively improve the SDF content and the physicochemical and functional properties of pea dietary fibre, which gives pea dietary fibre great application potential in functional foods.

Characterization of the Structure and Physicochemical Properties of Soluble Dietary Fiber from Peanut Shells Prepared by Pulsed Electric Fields with Three-Phase Partitioning

This study evaluated the impact of pulsed electric fields (PEFs) combined with three-phase partitioning (TPP) extraction methods on the physicochemical properties, functional properties, and structural characterization of the soluble dietary fiber (SDF) derived from peanut shells (PS). The findings of this study indicated that the application of a PEF-TPP treatment leads to a notable improvement in both the extraction yield and purity of SDF. Consequently, the PEF-TPP treatment resulted in the formation of more intricate and permeable structures, a decrease in molecular weight, and an increase in thermal stability compared to SDFs without TPP treatment. An analysis revealed that the PEF-TPP method resulted in an increase in the levels of arabinose and galacturonic acid, leading to enhanced antioxidant capacities. Specifically, the IC50 values were lower in SDFs which underwent PEF-TPP (4.42 for DPPH and 5.07 mg/mL for ABTS) compared to those precipitated with 40% alcohol (5.54 mg/mL for DPPH, 5.56 mg/mL for ABTS) and PEF75 (6.60 mg/mL for DPPH, 7.61 mg/mL for ABTS), respectively. Notably, the SDFs which underwent PEF-TPP demonstrated the highest water- and oil-holding capacity, swelling capacity, emulsifying activity, emulsion stability, glucose adsorption, pancreatic lipase inhibition, cholesterol adsorption, nitric ion adsorption capacity, and the least gelation concentration. Based on the synthesis scores obtained through PCA (0.536 > -0.030 > -0.33), which indicated that SDFs which underwent PEF-TPP exhibited the highest level of quality, the findings indicate that PEF-TPP exhibits potential and promise as a method for preparing SDFs.

Extraction of insoluble soybean fiber by alternating ultrasonic/alkali and its improved superior physicochemical and functional properties

Okara, as a by-product of soybean processing, is rich in insoluble dietary fiber (IDF), which is a carbohydrate polymer with various insoluble polysaccharides. Nowadays, the extraction of IDF with excellent functional properties has become a research hotspot. In this work, we further proposed an alternating alkali/ultrasound method for the efficient extraction of IDF. The sequential treatments of alkali (A-ISF), alkali-ultrasonic (AU-ISF), ultrasonic-alkali (UA-ISF), ultrasonic-alkali-ultrasonic (UAU-ISF) and alkali-ultrasonic-alkali (AUA-ISF) were applied to extract insoluble soybean fiber (ISF). FTIR and XRD results proved the typical structure of ISFs, and TGA results demonstrated the improved thermal stability of UAU-ISF and AUA-ISF. Chemical composition measurement showed that UAU-ISF and AUA-ISF exhibited higher cellulose content (>83 %). SEM results revealed that ultrasonic treatment led to a decomposition of okara matrix and significant porous structure in ISFs with an amplified collapse effect, resulting in an increase of the pore size of ISFs, and strengthening the properties of UAU-ISF and AUA-ISF in higher water (>15 g/g)/oil (>12 g/g) holding capacities, cholesterol binding capacity (>36 mg/g), and cation exchange capacity (>0.3 mmol/g), thus providing new insights for the preparation of ISF with high functional properties that are beneficial for human intestinal health.

Study of the structural characterization, physicochemical properties and antioxidant activities of phosphorylated long-chain inulin with different degrees of substitution

In this study, phosphorylated derivatives of long-chain inulin with different substitution degrees were prepared. The synthesized samples were named PFXL-1, PFXL-2, PFXL-3, and PFXL-4 according to their degree of substitution (from low to high). The structures of FXL and PFXL were characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy, and the results indicated the successful introduction of phosphate groups. FXL and PFXL were composed of two types of sugar, fructose and glucose, with a molar ratio of 0.977:0.023. The SEM results showed that phosphorylation changed the morphology of FXL from an irregular mass to small spherical aggregates. The XRD pattern showed that the crystallinity was reduced by the introduction of phosphate groups. The Mw of FXL was 2649 g/mol, and the Mw of PFXL-4 increased the most (2965 g/mol). Additionally, PFXL was more stable and uniform, and the absolute value of the PFXL potential reached 7.83 mV. Phosphorylation decreased the weight loss rate of FXL and improved the viscoelastic properties and antioxidant activity of FXL. This study presents a method for the modification of FXL, demonstrating that phosphorylation can enhance its physicochemical properties and physiological activity and suggesting its potential as a functional food and quality modifier.

Improvement of soluble dietary fiber quality in Tremella fuciformis stem by steam explosion technology: An evaluation of structure and function

Edible fungi by-products are rich in dietary fiber (DF). In this study, we used steam explosion (SE) to modify Tremella fuciformis (T. fuciformis) stem DF. The SE conditions were optimized using response surface methodology (RSM), and the soluble dietary fiber (SDF) extraction rate increased 1.42-fold (from 23.33 ± 0.42 % to 33.21 ± 0.28 %) under optimized conditions. SE destroyed the dense structure of SDF, which improved the specific surface area and thermal stability. Furthermore, the structural changes induced by SE resulted in improved functional properties, and SDF had better hydration properties (water holding capacity, oil holding capacity, and swelling capacity increased by 1.23, 1.59, and 1.24 times, respectively) and hypoglycemic capacity (glucose adsorption capacity increased 1.84-fold at 100 mmol/L glucose). Therefore, SE is an excellent modification method for improving quality of edible fungi processing by-products SDF.

Subcritical water treatment to modify insoluble dietary fibers from brewer's spent grain for improved functionality and gut fermentability

Lactic acid (LA)-assisted subcritical water treatment (SWT) was applied to modify the insoluble dietary fiber (IDF) from brewer's spent grain (BSG) for enhancing its functionality and gut fermentability. Modified IDFs were thoroughly characterized for their chemical and structural properties. The results revealed that increasing the treatment temperature and LA concentration reduced hemicellulose content in IDFs from 38.4 % to 0.7 %, alongside a decreased yield (84.8 %-51.4 %), reduced particle size (519.8-288.6 μm), and more porous structure of IDFs. These modifications were linked to improved functionalities, evidenced by the highest water and oil holding capacity increasing by 36 % and 67 %, respectively. Remarkably, the highest glucose adsorption capacity increased by 6.5 folds. Notably, modified IDFs exhibited slower in-vitro fermentation, elevated short-chain fatty acids (SCFAs) production, and a higher proportion of butyrate in SCFAs. These findings highlight the potential of LA-assisted SWT in transforming BSG-derived IDF into a valuable functional food ingredient.

Effects of high-pressure microfluidization treatment on the structural, physiochemical properties of insoluble dietary fiber in highland barley bran

High-pressure microfluidization treatment (HPMT) was performed on the insoluble dietary fiber (IDF) of highland barley bran (HBB), with conditions set at 60 MPa (IDF-60), 120 MPa (IDF-120), and two consecutive high-pressure treatments at 120 MPa (IDF-120-2), respectively. Then the particle size, structural, physicochemical and adsorption properties of different IDF samples were analyzed. After HPMT, the particle size of IDF samples gradiently decreased (p < 0.05), and part of IDF was transferred into soluble dietary fiber (SDF), accompanied by the decrease of hemicellulose and lignin content. In addition, the morphology of the IDF samples became more fragmented and wrinkled, and the two consecutive treatments at 120 MPa significantly damaged the crystalline structure of the IDF. Moreover, the adsorption capacities to water, oil, cholesterol, and NO2- were basically enhanced with the increase of treatment pressure and treatment number. The IDF-120-2 sample had the strongest water/oil-holding, swelling, and cholesterol trapping capacities, and the IDF-120 showed strongest NO2- trapping capacity (pH = 2). Through the correlation analysis, the adsorption capacities were positively to the particle size and SDF content, and negatively correlated with the specific surface area (SSA) and IDF content. The adsorption capacities of IDF for the four substances were positively correlated with each other.

Study of the acetylation-induced changes in the physicochemical and functional characteristics of insoluble dietary fiber from wheat bran

BACKGROUND

Wheat bran is rich in dietary fiber (DF), particularly insoluble dietary fiber (IDF). Although the benefits for human health following the consumption of these DFs have been documented, the lower water retention capacity (WRC) and other properties still limit the applications of DF. Therefore, the current research investigated the impact of acetylation on the changes in the corresponding physicochemical and functional properties of DF.

RESULTS

The current results indicated the acetylated group restricted the alignment of the molecular chains, which led to an increased amorphous phase in the fiber structure, followed by an enhanced thermal sensitivity and a reduced crystallinity as evidenced by X-ray diffraction (XRD). Moreover, the acetylation of the IDFs enhanced the cholesterol absorption capacity, but the corresponding antioxidant capacity and cation exchange capacity were reduced, which might be due to the partial loss of the phenolic compounds onto the polysaccharides during the modification. Interestingly, a lower degree of substitution (DS) of the IDF achieved from water-acetic anhydride modification led to a higher WRC and water swelling capacity (WSC). In contrast, a higher DS from acetic anhydride modification demonstrated a greatly improved in vitro hypoglycemic performance of the IDF, including α-amylase inhibitory activity and glucose dialysis retardation index (GDRI), compared to the other samples.

CONCLUSION

This study highlights a new approach to modify the functionality of IDFs via acetylation and the design of a novel IDF with hypoglycemic activity. © 2023 Society of Chemical Industry.

Effects of extraction methods on the structure and functional properties of soluble dietary fiber from blue honeysuckle (Lonicera caerulea L.) berry

The work within this study aimed to investigate and compare the effects of compound enzyme extraction (CE), ultrasonic chemical extraction (UC) and combined fermentation extraction (CF) on the physicochemical properties, microstructure, and functional properties of soluble dietary fiber (SDF) extracted from blue honeysuckle berries. The results showed that CE-SDF had higher crystallinity (32.41%). UC-SDF had the highest yield (13.32 ± 0.80 g/100 g). CF-SDF had the maximum inhibition of α-amylase (50.82 ± 0.76%) and α-glucosidase (54.87 ± 1.25%). The in vitro hypoglycemic activity of the three SDFs was observed in the order of CF > CE > UC. Meanwhile, the purity of SDF had a strong positive correlation with its antioxidant and in vitro hypoglycemic capacities. The crystallinity of SDF was found to be positively correlated with its molecular weight and thermal properties. Additionally, the sugar composition of SDF was found to be an important factor affecting its biological activity.

Application of ultrasound technology for the effective management of waste from fruit and vegetable

Food waste presents a continuous challenge for the food industry, leading to environmental pollution and economic issues. A substantial amount of waste, including by-products from fruits and vegetables, non-edible food items, and other waste materials, is produced throughout the food supply chain, from production to consumption. Recycling and valorizing waste from perishable goods is emerging as a key multidisciplinary approach within the circular bio-economy framework. This waste, rich in raw by-products, can be repurposed as a natural source of ingredients. Researchers increasingly focus on biomass valorization to extract and use components that add significant value. Traditional methods for extracting these bio-compounds typically require the use of solvents and are time-consuming, underscoring the need for innovative techniques like ultrasound (US) extraction. Wastes from the processing of fruits and vegetables in the food industry can be used to develop functional foods and edible coatings, offering protection against various environmental factors. This comprehensive review paper discusses the valorization of waste from perishable items like fruits and vegetables using US technology, not only to extract valuable components from waste but also to treat wastewater in the beverage industry. It also covers the application of biomolecules recovered from this process in the development of functional foods and packaging.

Effects of hazelnut soluble dietary fiber on lipid-lowering and gut microbiota in high-fat-diet-fed rats

Hazelnut is one of the most popular nuts in the world, rich in nutrients and various active substances. In this study, soluble dietary fiber (SDF) was extracted from hazelnut kernels, and its physicochemical properties and absorbability were explored. Hazelnut-SDF exhibited ideal water-holding, oil-holding and swelling capacity, and glucose, cholesterol and cholate absorbing ability. Scanning electron microscopy and fourier transform infrared spectroscopy showed that hazelnut-SDF had typical polysaccharide structure of functional groups. The main monosaccharides were identified as arabinose, rhamnose, xylose, ribose, glucuronic acid, mannose and glucose by gas chromatography-mass spectrometry. In high-fat diet rats, hazelnut-SDF could improve serum lipid parameters, inhibit lipid accumulation in liver and adipocytes, and regulate the expression level of liver lipid synthesis-related genes. It also could adjust intestinal short chain fatty acids, promote the composition and structure of intestinal microbiota, and significantly balance the abundance of Alloprevotella, Fusicatenibacter, Lactobacillus, Roseburia, Ruminococcaceae_UCG-005, Ruminococcaceae_UCG-014 and Clostridiales. The results concluded that oral administration of hazelnut-SDF could alleviate hyperlipidemia and obesity, and might serve as a potential functional food ingredient.

Enhancement of γ-Aminobutyric Acid and the Characteristics of Nutrition and Function in White Quinoa through Ultrasound Stress at the Pre-Germination Stage

The global production of quinoa has been increasing in recent years. In plant-based foods, ultrasound stress has received increasing attention, owing to its ability to enhance the production of primary and secondary metabolites. We studied the effects of ultrasonic stress at the pre-germination stage on the γ-aminobutyric acid (GABA) accumulation and characteristics of nutrition and function in quinoa. The results showed that ultrasonic conditions of 100 W for 4 min promoted an increase in GABA content by 9.15-fold, to 162.47 ± 6.69 mg/100 g·DW, compared to that of untreated quinoa, through promoting a 10.2% and 71.9% increase in the water absorption and glutamate decarboxylase activity of quinoa, respectively. Meanwhile, compared to untreated quinoa, ultrasonic stress at the pre-germination stage enhanced the total phenolic, total flavonoid, and total saponin contents of quinoa by 10.2%, 33.6%, and 90.7%, to 3.29 mg GA/g·DW, 104.0 mg RE/100 g·DW, and 7.13 mg/g, respectively, without decreasing its basic nutritional quality. Ultrasonic stress caused fissures on the surface of quinoa starch particles. Additionally, germination under ultrasonic stress increased the n3 polyunsaturated fatty acids by 14.4%. Furthermore, ultrasonic stress at the pre-germination stage promoted the scavenging of 2,2-diphenyl1-picrylhydrazyl radicals and inhibitions of α-amylase, α-glucosidase, and pancreatic lipase by 14.4%, 14.9%, 24.6%, and 20.0% in vitro, compared to untreated quinoa. The results indicated that the quinoa sprouted via ultrasonic stress could represent a promising method through which to develop nutritionally balanced whole grains rich in GABA, with hypoglycemic and hypolipidemic activities, which could provide theoretical support for the development of functional whole-grain foods based on quinoa.

Optimization of Chemical Extraction Conditions of Dietary Fiber from Cistanche deserticola Residues and Its Structural Characteristics and Physicochemical and Functional Properties

Cistanche deserticola residues are by-products of the industrial production of Cistanche deserticola, which are currently often discarded, resulting in the waste of resources. In order to achieve the efficient utilization of Cistanche deserticola, dietary fiber from Cistanche deserticola residues was extracted chemically and the optimization of the extraction conditions was performed, using the response surface methodology to study the effects of the NaOH concentration, extraction temperature, extraction time, and solid-liquid ratio on the yield of water-soluble dietary fiber (SDF). The structural, physicochemical, and functional properties of the dietary fiber were also investigated. The results showed that the optimal conditions were as follows: NaOH concentration of 3.7%, extraction temperature of 71.7 °C, extraction time of 89.5 min, and solid-liquid ratio of 1:34. The average yield of SDF was 19.56%, which was close to the predicted value of 19.66%. The two dietary fiber types had typical polysaccharide absorption peaks and typical type I cellulose crystal structures, and the surface microstructures of the two dietary fiber types were different, with the surface of SDF being looser and more porous. Both dietary fiber types had good functional properties, with SDF having the strongest water-holding capacity and the strongest adsorption capacity for nitrite, cholesterol, sodium cholate, and glucose, while IDF had a better oil-holding capacity. These results suggest that Cistanche deserticola residues are a good source of dietary fiber and have promising applications in the functional food processing industry.

Physicochemical Properties and Hypolipidemic Activity of Dietary Fiber from Rice Bran Meal Obtained by Three Oil-Production Methods

This study investigated the effects of three oil production methods on the physicochemical properties of dietary fiber from rice bran flour, and the hypolipidemic effects of the dietary fibers were investigated in vitro and in vivo. The particle size results showed that the organic-solvent-impregnated rice bran meal dietary fiber (N-RBDF) had the smallest average particle size and the aqueous enzymatic rice bran meal dietary fiber (E-RBDF) had the narrowest particle size distribution. Scanning electron microscopy (SEM) results demonstrated that all three kinds of rice bran meal dietary fibers (RBDFs) were irregularly flaky. Fourier transform infrared spectroscopy (FT-IR) results revealed that the three RBDFs had similar reactive groups, and X-ray diffraction (XRD) results indicated that all three RBDFs were cellulose type I crystals. The results of thermogravimetric analysis showed that the lignin content of N-RBDF was significantly lower than that of the other two. Among the three kinds of RBDFs, E-RBDF had higher water retention capacity, swelling capacity, oil holding capacity, and adsorption capacity for cholesterol and sodium bile salts. The results of experimental studies in hyperlipidemic rats showed that all three kinds of RBDFs significantly reduced triglycerides (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) and elevated high-density lipoprotein cholesterol (HDL-C) in the serum of hyperlipidemic rats; they also significantly lowered malondialdehyde (MDA) and elevated total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) activities in the livers of rats. In addition, all three kinds of RBDFs decreased aminotransferase (ALT) and aminotransferase (AST) activity in serum and also improved liver steatosis and reduced atherosclerosis index (AI) in rats with hyperlipidemia. Our study provides a reference for the development and utilization of rice bran meal and the application of rice bran meal dietary fiber in food processing.

Optimization of Ultrasound-Assisted Extraction of Dietary Fiber from Yellow Dragon Fruit Peels and Its Application in Low-Fat Alpaca-Based Sausages

The main objective of this study was to optimize the extraction of dietary fiber (insoluble dietary fiber and soluble dietary fiber) and degree of esterification from yellow dragon fruit peels using ultrasound-assisted extraction. Additionally, the study aimed to investigate the potential application of this fiber as a fat replacement in alpaca-based sausages. The optimization process for extracting dietary fiber and degree of esterification involved considering various factors, including the liquid-to-solid ratio, pause time, and total ultrasound application time. A Box-Behnken design consisting of 15 treatments was employed to determine the optimal levels for ultrasound-assisted extraction. The optimized conditions were found to be a liquid-to-solid ratio = 30 mL/g, pause time = 1 s, and total ultrasound application time = 60 min, which resulted in the highest values of insoluble dietary fiber (61.3%), soluble dietary fiber (10.8%), and the lowest value of degree of esterification (39.7%). The predicted values were validated against experimental data and showed no significant differences (p > 0.05). Furthermore, a completely randomized design was utilized to assess the effect of dietary fiber on replacing fat content during the production of alpaca-based sausages. The findings revealed that up to 78% of the fat content could be successfully replaced by soluble dietary fiber obtained from yellow dragon fruit peels when compared to high-fat sausages. Additionally, experimental sausages using soluble dietary fiber showed similar (p > 0.05) quality characteristics, such as hardness (24.2 N), chewiness (11.8 N), springiness (0.900), cohesiveness (0.543), redness (a* = 17.4), and chroma values (20.0), as low-fat commercial sausages.

Anti-Inflammatory and Anti-Oxidative Effects of Polysaccharides Extracted from Unripe Carica papaya L. Fruit

This study evaluated the antioxidative and anti-inflammatory activities of polysaccharides extracted from unripe Carica papaya L. (papaya) fruit. Three papaya polysaccharide (PP) fractions, namely PP-1, PP-2, and PP-3, with molecular weights of 2252, 2448, and 3741 kDa, containing abundant xylose, galacturonic acid, and mannose constituents, respectively, were obtained using diethylaminoethyl-Sepharose™ anion exchange chromatography. The antioxidant capacity of the PPs, hydroxyl radical scavenging assay, ferrous ion-chelating assay, and reducing power assay revealed that the PP-3 fraction had the highest antioxidant activity, with an EC50 (the concentration for 50% of the maximal effect) of 0.96 mg/mL, EC50 of 0.10 mg/mL, and Abs700 nm of 1.581 for the hydroxyl radical scavenging assay, ferrous ion-chelating assay, and reducing power assay, respectively. In addition, PP-3 significantly decreased reactive oxygen species production by 45.3%, NF-κB activation by 32.0%, and tumor necrosis factor-alpha and interleukin-6 generation by 33.5% and 34.4%, respectively, in H2O2-induced human epidermal keratinocytes. PP-3 exerts potent antioxidative and anti-inflammatory effects; thus, it is a potential biofunctional ingredient in the cosmetic industry.

Modification of Ginseng Insoluble Dietary Fiber by Enzymatic Method: Structural, Rheological, Thermal and Functional Properties

In this study, the effects of enzymatic modification using cellulase/xylanase on the composition and structural and functional properties of ginseng insoluble dietary fiber (G-IDF) were evaluated. Fourier transform infrared spectroscopy and scanning electron microcopy showed that enzymatic extraction treatment caused obvious structural alterations in ginseng-modified (G-MIDF) samples, which exhibited more porous and completely wrinkled surfaces. Comparing the peak morphology of G-MIDF with untreated IDF using X-ray diffractometry, the G-MIDF sample exhibited split peaks at a 2θ angle of 23.71°, along with the emergence of sharp peaks at 28.02°, 31.78°, and 35.07°. Thermo-gravimetric analysis showed that G-MIDF exhibited a specified range of pyrolysis temperature and is suitable for food applications involving processing at temperatures below 300 °C. Overall, it was evident from rheograms that both G-IDF and G-MIDF exhibited a resemblance with respect to viscosity changes as a function of the shear rate. Enzymatic treatment led to significant (p < 0.05) improvement in water holding, oil retention, water swelling, nitrite ion binding, bile acid binding, cholesterol absorption, and glucose absorption capacities.

Regulation strategy, bioactivity, and physical property of plant and microbial polysaccharides based on molecular weight

Structural features affect the bioactivity, physical property, and application of plant and microbial polysaccharides. However, an indistinct structure-function relationship limits the production, preparation, and utilization of plant and microbial polysaccharides. Molecular weight is an easily regulated structural feature that affects the bioactivity and physical property of plant and microbial polysaccharides, and plant and microbial polysaccharides with a specific molecular weight are important for exerting their bioactivity and physical property. Therefore, this review summarized the regulation strategies of molecular weight via metabolic regulation; physical, chemical, and enzymic degradations; and the influence of molecular weight on the bioactivity and physical property of plant and microbial polysaccharides. Moreover, further problems and suggestions must be paid attention to during regulation, and the molecular weight of plant and microbial polysaccharides must be analyzed. The present work will promote the production, preparation, utilization, and investigation of the structure-function relationship of plant and microbial polysaccharides based on their molecular weight.

Synergistic effect of ultrasound and citric acid treatment on functional, structural and storage properties of hog plum (Spondias mombin L) bagasse

A novel approach in promoting the valorisation of fruit waste as potential bio-ingredients in food applications is gaining research attention in recent times. In the present study, hog plum bagasse (HPB) treated with citric acid alone (0.12 dm3, 99.0% purity) and in synergistic treatment with ultrasound (40 KHz, 400 W, 0.348 W/cm3, 60 min, 80 °C). Treated samples were evaluated for proximate and lignocellulose composition, functional, bioactive, structural, morphology and microbial properties, while the untreated samples served as control. HPB showed varied proximate values with treatment effect. Notably, a significant reduction (42.06%) was observed in fibre content. A similar reduction was observed in the hemicellulose and lignin fraction but improved the yield of the cellulose component. Furthermore, treatment increased bulk density (0.120-0.131 g/cm3), water absorption capacity (5.60-6.35 g/g), swelling power (8.85-9.94 g/g) and solubility index (1.01-2.32%) but reduced oil absorption capacity (7.50-4.15 g/g). All colour parameters were reduced with treatment, while the total phenolic compound and antioxidant capacity of treated bagasse improved by 24.70% and 45.37%. Fourier transform infra-red spectroscopy alterations were observed in the absorption spectra with treatment, while scanning electron microscopestructure in treated samples showed cavity formation. Also, the microbial population was reduced to a non-detectable level after treatment. Ultrasound-assisted treatment of HPB holds a valorisation potential for its food application by relevant agro-based industries.

Effects of ultrasonic assisted high-temperature cooking method on the physicochemical structure characteristics and in vitro antioxidant capacities of dietary fiber from Dendrocalamus brandisii Munro shoots

In this study, the ultrasonic assisted high-temperature cooking extraction method of soluble dietary fiber from bamboo shoots was optimized by response surface methodology, and the effects of ultrasonic assisted high-temperature cooking extraction on the structural characteristics, physicochemical properties and antioxidant activity of soluble dietary fiber (SDF) from bamboo shoots were evaluated. The yield of modified UH-SDF¹ was significantly higher than that of untreated D-SDF². FTIR and XRD confirmed that UH-SDF had more hydrophilic groups and higher crystallinity (28.73 %), resulting in better thermal stability. SEM observation showed that UH-SDF exhibited a more loose microstructure, and the particle size of UH-SDF (601.52 μm) was significantly smaller than that of D-SDF (242.59 μm), so UH-SDF had a larger specific surface area. In addition, UH-SDF has stronger water holding capacity, water swelling capacity and oil holding capacity than D-SDF. The DPPH radical and hydroxyl radical scavenging rates of UH-SDF were 8.91 % and 7.49 % higher than those of D-SDF. In addition, the reducing ability of UH-SDF was higher than that of D-SDF, which had better antioxidant activity. In summary, UH-SDF has the potential to be developed as an anti-inflammatory functional food.

Extraction Optimization, Characterization and Biological Activities of Polysaccharide Extracts from Nymphaea hybrid

In this study, polysaccharide-rich Nymphaea hybrid extracts (NHE) were obtained using the ultrasound-assisted cellulase extraction (UCE) method optimized by response surface methodology (RSM). The structural properties and thermal stability of NHE were characterized by Fourier-transform infrared (FT-IR), high-performance liquid chromatography (HPLC) and thermogravimetry-derivative thermogravimetry (TG-DTG) analysis, respectively. Moreover, the bioactivities of NHE, including the antioxidant, anti-inflammatory, whitening and scratch healing activities were evaluated by different in vitro assays. NHE conveyed a good ability to scavenge against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and inhibit the hyaluronidase activity. NHE can effectively protect the HaCaT cells against oxidative damage by inhibiting the intracellular reactive oxygen species (ROS) production in the H₂O₂ stimulation assays and promoting the proliferation and migration in the scratch assays. In addition, NHE was proven to inhibit melanin production in B16 cells. Collectively, the above results seem to be the evidence needed to promote the potential of NHE to be regarded as a new functional raw material in the cosmetics or food industries.

Obtaining non-digestible polysaccharides from distillers' grains of Chinese baijiu after extrusion with enhanced antioxidation capability

Distillers' grains of Chinese Baijiu (DGS) presents a significant challenge to the environmentally-friendly production of the brewing industry. This study utilized screw extrusion to modify the morphological and crystalline characteristics of DGS, resulting in a 316 % increase in the yield of non-digestible polysaccharides extraction. Physiochemical characteristics of extracted polysaccharides were variated, including infrared spectrum, monosaccharide composition, and molecular weight. Polysaccharides extracted from extruded DGS exhibited enhanced inhibitory capacity on α-amylase activity and starch hydrolyzation, as compared to those extracted from unextruded DGS. Additionally, the ABTS, DPPH, and OH radical scavenging efficiencies took a maximum increase of 1.20, 1.38, and 1.02-fold, correspondingly. Extrusion is a novel approach for the recycling non-digestible polysaccharides from DGS, augmenting the bioactivity of extracts and their potential application in functional food.

The structural and functional properties of dietary fibre extracts obtained from highland barley bran through different steam explosion-assisted treatments

The effects of steam explosion (SE)-assisted ultrasound (SEU), citric acid (SEC), sodium hydroxide (SEA), and cellulase (SEE) treatment on the properties of soluble dietary fibre (SDFP) extracted from highland barley bran were analysed. The results showed that SE pretreatment combined with other methods effectively improves the SDFP yield. The highest yield of SDF (20.01%) was obtained through SEA treatment. SEU-SDFP had a loose and porous structure, whereas the surface of SEC-SDFP and SEA-SDFP presented a complicated and dense texture. Although SE pretreatment reduced the thermal stability of SDFP, SEC and SEE treatment maintained its thermal stability. Furthermore, SEU-SDFP exhibited the highest water and oil holding capacities, and cholesterol and nitrite ion adsorption capacities. SEE-SDFP exhibited the best DPPH and ABTS radical scavenging abilities. In summary, four SE-assisted extraction methods had different advantages, and highland barley bran SDF can be considered as a potential functional additive in the food industry.

Development of antimicrobial gelatin-ulvan-beeswax composite films: Optimization of formulation using mixture design methodology

A new generation of antimicrobial film was developed by incorporation of ulvan extracted from Ulva intestinalis into gelatin from common carp scale and its water sensitivity was reduced with addition of beeswax. Optimum composition of gelatin (0-100%w/w), ulvan (0-100%w/w) and beeswax (0-10%w/w) for achieving composite films with minimum water solubility (S) and water vapor permeability (WVP) and maximum tensile strength (TS), elongation at break point (EAB) and antibacterial effect on E. coli (EC) were investigated using mixture design methodology. Both pure gelatin and ulvan films and their composites had relatively good mechanical and optical properties. Addition of ulvan to gelatin produced composite films with good antibacterial properties but water resistance of all the films was weak. Addition of beeswax up to ∼5 % improved the water resistance and mechanical properties of the films without jeopardizing their antibacterial properties. The final optimum formulation with a desirability of 0.709 was achieved as 52.18 % of gelatin, 40.83 % of ulvan and 6.97 % of beeswax resulting in a minimum possible S (40 %) and WVP (1.86 10^-10 g/ms Pa) and maximum possible TS (6.23 MPa) and EAB (89 %) with good EC (7.66 mm). Finally, good mechanical, thermal and microstructural properties of the optimum composite film was confirmed. Altogether, a combination of ulvan and beeswax can be a promising solution for development of gelatin films with both antimicrobial properties and lower water sensitivity.

Effect of ultrasonic degradation on the structural feature, physicochemical property and bioactivity of plant and microbial polysaccharides: A review

With the bioactivities of antioxidant, anti-bacteria, anti-inflammation, immune regulation, antitumor and anti-coagulation, plant and microbial polysaccharides have been widely used in foods, medicine and cosmetics. However, how structure features affect the physicochemical property and bioactivity of plant and microbial polysaccharides is still unclear. Ultrasonic degradation usually degrades or modifies plant and microbial polysaccharides with different physicochemical properties and bioactivities by affecting their chemical or spatial structures via mechanical bond breaking and cavitation effects. Therefore, ultrasonic degradation might be an effective strategy for producing bioactive plant and microbial polysaccharides and analyzing their structure-function relationship. Present review summarized the influence of ultrasonic degradation on structural feature, physicochemical property and bioactivity of plant and microbial polysaccharides. Moreover, further problems need to be paid attention to during the application of ultrasonication for plant and microbial polysaccharides degradation are also recommended. Overall, present review will provide an efficient method for producing enhanced bioactive plant and microbial polysaccharides and analyzing their structure-activity relationship based on ultrasonic degradation.

Microfibrillated Cellulose with a Lower Degree of Polymerization; Synthesis via Sulfuric Acid Hydrolysis under Ultrasonic Treatment

A new approach is being considered for obtaining microfibrillated cellulose with a low degree of polymerization by sulfuric acid hydrolysis with simultaneous ultrasonic treatment under mild conditions (temperature 25 °C, 80% power control). Samples of initial cellulose, MCC, and MFC were characterized by FTIR, XRF, SEM, DLS, and TGA. It was found that a high yield of MFC (86.4 wt.%) and a low SP (94) are observed during hydrolysis with ultrasonic treatment for 90 min. It was shown that the resulting microfibrillated cellulose retains the structure of cellulose I and has an IC of 0.74. It was found that MFC particles are a network of fibrils with an average size of 91.2 nm. ζ-potential of an aqueous suspension of MFC equal to -23.3 mV indicates its high stability. It is noted that MFC has high thermal stability, the maximum decomposition temperature is 333.9 °C. Simultaneous hydrolysis process with ultrasonic treatment to isolate MFC from cellulose obtained by oxidative delignification of spruce wood allows to reduce the number of stages, reduce energy costs, and expand the scope.

Multivariate analysis of structural and functional properties of fibres from apple pomace using different extraction methods

In recent years, diets rich in fibres have become more popular due to their well-documented beneficial health effects. This has driven exploration of novel dietary fibres from various bioresources. Apple pomace, an industrial waste rich in fibres was used in this study to extract the insoluble dietary fibres. The effect of various extraction methods (hot water, acid, and alkali) on the physico-chemical, structural and functional properties, and prebiotic activity of dietary fibres was evaluated. Hot water extraction resulted in highest yield of dietary fibres in comparison to other methods (p < 0.05). All the fractions resulted in different organization of fibrous components as depicted by scanning electron micrographs, Fourier Transform Infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) pattern and Thermo Gravimetric Analysis (TGA). The acid extracted fibre fraction was observed to be amorphous with loose and porous structure whereas the alkali extracted fraction was more thermal stable based on TGA profile. Among the functional properties, acid extracted dietary fibres fraction possessed highest water and oil holding capacity (p < 0.05). The hot water extracted dietary fraction resulted in maximum increase in viable cell count of standard probiotic strains Lactobacillus sporogenes and Streptococcus faecalis. The Principal Component Analysis revealed that acid extracted fraction possessed better functional activity which also correlates with the structural properties whereas for prebiotic activities, the fibre obtained from hot water extraction method served the best method. These results indicate that dietary fibres extracted through hot water can be employed as a potential prebiotic substrate for the probiotic cultures and could be further explored in foods to improve textural, functional, and bioactive properties of foods.

Graphical Abstract

Physicochemical, structure properties and in vitro hypoglycemic activity of soluble dietary fiber from adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) bran treated by steam explosion

To enhance the content of adlay bran soluble dietary fiber (SDF) and improve its functionality, we investigated the influences of steam explosion (SE) on the physicochemical, structural properties, and in vitro hypoglycemic activities of adlay bran SDF. The cellulose, hemicellulose, and lignin contents of adlay bran decreased significantly after SE treatment. When the SE strength was 0.8 MPa for 3 min, the SDF content was 9.37%, which was a significant increase of 27.48% compared to the control. Under these conditions, SDF showed the highest oil-holding capacity (OHC) (2.18 g/g), cholesterol adsorption capacity (CAC) (27.29 mg/g), glucose adsorption capacity (GAC) (15.54 mg/g), glucose dialysis retardation index (GDRI) (36.57%), and α-Amylase activity inhibition ratio (α-AAIR) (74.14%). Compared with SDF from untreated adlay bran, SDF from SE-treated adlay bran showed lower weight molecular. In addition, differential scanning calorimetry (DSC) measurement showed that the peak temperature of SDF from adlay bran treated by SE increased by 4.19°C compared to the untreated SDF sample. The structure of SDF from adlay bran treated by SE showed that the SDF surface was rough and poriferous and the specific surface areas increased. In conclusion, SE pretreatment increases the content of SDF in adlay bran and improves its physicochemical, structural properties, and biological activities, which will be beneficial for the further exploitation of adlay bran.

Potential application of modified date powder by microwave radiation, ultrasonication and chemical pretreatments as coffee substitute: its biochemical properties and consumer preferences

To consider the suitability of modified date powder as a coffee substitute, the biochemical and antioxidant properties of date powder were modified by hydrochloric acid-ethanol (HAE), alkaline hydrogen peroxide (AHP), combined with ultrasound (U) microwave (MW) radiation. The results showed that the highest antioxidant activity was observed in HAE and HAE-U treated date powders. The total flavonoid content of the date powder increased by 40.8% and 100% in response to the AHP-MW and HAE-U treatments, respectively. Fourier transform infrared spectroscopy did not show any abnormal or unknown peaks in the analyzed range of the treated samples. Therefore, modification of biochemical and sensory properties of date powder by chemical and irradiation treatments did not have a detrimental effect on changing the structure of its chemical compounds or the formation of harmful compounds in it. Sensory evaluations showed that replacing coffee powder with modified date powder by up to 25% did not have significant effects on the sensory properties of the coffee drink. Finally, the results showed that modifying the biochemical and antioxidant properties of date powder by the HAE method as coffee substitute can increase the nutritional properties of coffee drinks while also reducing the expenses of the coffee industry.

Graphical abstract

Characterization of the structural, physicochemical, and functional properties of soluble dietary fibers obtained from the peanut shell using different extraction methods

Objective

To propose a possible solution for a peanut by-product, peanut shell (PS), this study evaluated the effects of different methods, including enzymatic extraction (E-SDF), microwave extraction (M-SDF), and pulsed electric field extraction (PEF-SDF), on the characterization of soluble dietary fibers (SDFs) from PS.

Methods

We determined the physicochemical properties, including water- and oil-holding capacities (WHC and OHC), emulsifying properties, rheological properties, functional properties, including pancreatic lipase activity inhibition (PRAI), glucose and cholesterol adsorption capacities (GAC and CAC), and the structural properties of SDFs.

Results

The results showed that PEF-SDF possessed the highest WHC, OHC, and emulsifying properties. M-SDF and PEF-SDF appeared to have more complex and porous structures, and they showed small molecular weights. Notably, PEF-SDF showed the strongest capacities in CAC, GAC, and PRAI.

Conclusions

The results indicate that PEF-SDF is a potential SDF preparation method for a promising dietary fiber (DF) source, PS.

A Comparative Study on Extraction and Physicochemical Properties of Soluble Dietary Fiber from Glutinous Rice Bran Using Different Methods

The methods of hot water extraction and ultrasound-assisted enzymatic treatment were applied for extracting the soluble dietary fiber from the glutinous rice bran in the study. Based on the single factor experiment for the hot water method, the optimum parameters of the extraction time of 120 min, solid-liquid ratio 1:20 (w/v), and pH 8.0, as well as the extraction temperature 80 °C, were obtained, while the yield and purity of SDF reached 31.83 ± 0.06% and 93.28 ± 0.27%, respectively. Furthermore, the SDF yield was improved to 34.87 ± 0.55% by using the ultrasound-assisted enzymatic treatment under the optimum conditions of cellulase dosage 9 × 103 U/g and ultrasonic temperature of 50 °C. Similar polysaccharide compositions were detected based on the infrared spectroscopic analysis. Compared with the SDF obtained from hot water extraction, the whiteness, solubility, water holding capacity, and swelling properties of SDF extracted by ultrasound-assisted enzymatic method improved significantly. These results demonstrated that both two strategies could be applied to SDF extraction in practical production, and the ultrasound-assisted enzymatic method might be an effective tool to improve the functional properties of SDF.

Effects of electron beam irradiation treatment on the structural and functional properties of okara insoluble dietary fiber

BACKGROUND

Insoluble dietary fiber (IDF) has beneficial physiological effects, such as the promoting of intestinal peristalsis, the improving of intestinal flora, and the absorbing of some harmful substances. Okara, a byproduct of soybean processing, is a potential source of IDF. But the larger particle size and poor water solubility of okara IDF have adverse effects on sensory properties and functional characteristics. Therefore, we used an emerging type of physical method is electron beam irradiation (EBI) to modify okara, and investigated that the effects of EBI doses on the structure and functional properties of okara IDF.

RESULTS

It was found that the electron beam treatment damaged the crystalline structure of IDF. Observation of the surface of EBI-treated IDF revealed a loose and porous morphology rather than the typical smooth structure. At a dose of 6 kGy, a smallest particle size and largest specific surface area of IDF was obtained, and these factors increased the apparent viscosity of an IDF dispersion. The water holding capacity, swelling capacity and the oil holding capacity upon irradiation at 6 kGy increased 74.13%, 84.76% and 41.62%, respectively. In addition, the capacity for adsorption of cholesterol, sodium cholate, glucose and nitrite ion were improved after electron beam treatment.

CONCLUSION

The modified okara IDF showed improved particle sizes and hydration properties, and these changes correlated with an improvement to the rough taste of IDF and improvements to the texture and storage period upon supplementation into food. © 2022 Society of Chemical Industry.

Comparison of physicochemical and in vitro hypoglycemic activity of bamboo shoot dietary fibers from different regions of Yunnan

In this study, the physicochemical properties, thermal characteristics, and in vitro hypoglycemic activity of dietary fibers extracted from four bamboo shoots were characterized and compared. The results showed that Dendrocalamus brandisii Munro (C-BSDF) had the highest dietary fiber content (6.1%) and the smallest particle size (222.21 μm). SEM observations found that C-BSDF exhibited a loose and porous microstructure, while FTIR and XRD confirmed that C-BSDF had a higher degree of decomposition of insoluble dietary fiber components and the highest crystallinity, resulting in a better microstructure. Furthermore, C-BSDF exhibited excellent physiochemical properties with the highest water hold capacity, water swelling capacity, and preferable oil holding capacity. Thermal analysis showed that C-BSDF had the lowest mass loss (64.25%) and the highest denaturation temperature (114.03°C). The hypoglycemic activity of dietary fibers from bamboo shoots were examined in vitro and followed this order of activity: C-BSDF>D-BSDF>A-BSDF>B-BSDF. The inhibition ratios of GAC, GDRI and α-amylase activity of C-BSDF were 21.57 mmol/g, 24.1, and 23.34%, respectively. In short, C-BSDF display excellent physicochemical and functional properties due to its high soluble dietary fiber content, small particle size with a high specific surface area, and loose microstructure. Thus, D. brandisii Munro can be considered a promising new source of dietary fiber for hypoglycemic health products.

Improving the adsorption characteristics and antioxidant activity of oat bran by superfine grinding

Oat bran (OB) is a by-product of oat, which is rich in β-glucan. As a new food processing technology, ultrafine powder can improve the surface properties of samples. OB with different grinding times was prepared, and its functional components, physical properties, adsorption properties, and antioxidant properties were evaluated. Results showed that with increased grinding times, the average particle size of OB decreased significantly (p < .05). And the water-holding capacity, swelling capacity, and water solubility index of OB increased significantly (p < .05), whereas the animal and vegetable oil-holding capacities decreased. Oat bran could adsorb cholic acid and glucose, which was related to the time of superfine grinding. In addition, the antioxidant capacity of OB was improved after superfine grinding. Related analysis shows that there was significant positive relationship between β-glucan, polyphenols and soluble dietary fibers and antioxidant indicators (p < .05). The Fourier transform infrared (FTIR) results showed that the FTIR spectra of OB powder with different crushing times were similar. On the basis of the above analyses, it is suggested that OB prepared by superfine grinding for 5 min had good physical and chemical properties and antioxidant properties and is widely used in food.

Effect of compound dietary fiber of soybean hulls on the gel properties of myofibrillar protein and its mechanism in recombinant meat products

Response surface methodology was used to determine the optimum ratio of rice husk dietary fiber, soybean hull dietary fiber, and inulin as 1.40, 1.42, and 3.24%. The effects of compound and single dietary fiber on water holding capacity, gel strength, secondary structure, rheological properties, chemical action force, and microstructure of myofibrillar proteins (MP) gel were investigated. The application of composite dietary fiber significantly (P < 0.05) improved the gel strength, water holding capacity and storage modulus (G') of MP gel. Fourier transform infrared spectrum analysis shows that the addition of compound dietary fiber can make the gel structure more stable. The effect of dietary fiber complex on the chemical action of MP gel was further studied, and it was found that hydrophobic interaction and disulfide bond could promote the formation of compound gel. By comparing the microstructure of the MP gel with and without dietary fiber, the results showed that the MP gel with compound dietary fiber had smaller pores and stronger structure. Therefore, the rice hull dietary fiber, the soybean hull dietary fiber and the inulin are compounded and added into the low-fat recombinant meat product in a proper proportion, so that the quality characteristics and the nutritional value of the low-fat recombinant meat product can be effectively improved, the rice hull dietary fiber has the potential of being used as a fat substitute, and a theoretical basis is provided for the development of the functional meat product.