Effects of extraction methods and particle size distribution on the structural, physicochemical, and functional properties of dietary fiber from deoiled cumin

Fermentation of millet bran with Bacillus natto: enhancement of bioactivity levels and the bioactivity of bran extract

BACKGROUND

Millet bran (MB), a byproduct of millet production, is rich in functional components but it is underutilized. In recent years, researchers have shown that fermentation can improve the biological activity of cereals and their byproducts. This study used Bacillus natto to ferment millet bran to improve its added value and broaden the application of MB. The bioactive component content, physicochemical properties, and functional activity of millet bran extract (MBE) from fermented millet bran were determined.

RESULTS

After fermentation, the soluble dietary fiber (SDF) content increased by 92.0%, the β-glucan content by 164.4%, the polypeptide content by 111.4%, the polyphenol content by 32.5%, the flavone content by 16.4%, and the total amino acid content by 95.4%. Scanning electron microscopy revealed that the microscopic morphology of MBE changed from complete and dense blocks to loosely porous shapes after fermentation. After fermentation, the solubility, water-holding capacity, and viscosity significantly increased and the particle size decreased. Moreover, the glucose adsorption capacity (2.1 mmol g-1), glucose dialysis retardation index (75.3%), and α-glucosidase inhibitory (71.4%, mixed reversible inhibition) activity of the fermented MBE (FMBE) were greater than those of the unfermented MBE (0.99 mmol g-1, 32.1%, and 35.1%, respectively). The FMBE presented better cholesterol and sodium cholate (SC) adsorption properties and the adsorption was considered inhomogeneous surface adsorption.

CONCLUSION

Fermentation increased the bioactive component content and improved the physicochemical properties of MBE, thereby improving its hypoglycemic and hypolipidemic properties. This study not only resolves the problem of millet bran waste but also encourages the development of higher value-added application methods for millet bran. © 2024 Society of Chemical Industry.

Combined dilute alkali and milling process enhances the functionality and gut microbiota fermentability of insoluble corn fiber

In this study, we developed a process combining dilute alkali (NaOH or NaHCO3) and physical (disk milling and/or ball milling) treatments to improve the functionality and fermentability of corn fiber. The results showed that combining chemical with physical processes greatly improved the functionality and fermentability of corn fiber. Corn fiber treated with NaOH followed by disk milling (NaOH-DM-CF) had the highest water retention (19.5 g/g), water swelling (38.8 mL/g), and oil holding (15.5 g/g) capacities. Moreover, NaOH-DM-CF produced the largest amount (42.9 mM) of short-chain fatty acid (SCFA) during the 24-hr in vitro fermentation using porcine fecal inoculum. In addition, in vitro fermentation of NaOH-DM-CF led to a targeted microbial shifting to Prevotella (genus level), aligning with a higher fraction of propionic acid. The outstanding functionality and fermentability of NaOH-DM-CF were attributed to its thin and loose structure, decreased ester linkages and acetyl groups, and enriched structural carbohydrate exposure.

Research on pear residue dietary fiber and Monascus pigments extracted through liquid fermentation

Pear residue, a byproduct of pear juice extraction, is rich in soluble sugar, vitamins, minerals, and cellulose. This study utilized Monascus anka in liquid fermentation to extract dietary fiber (DF) from pear residue, and the structural and functional characteristics of the DF were analyzed. Soluble DF (SDF) content was increased from 7.9/100 g to 12.6 g/100 g, with a reduction of average particle size from 532.4 to 383.0 nm by fermenting with M. anka. Scanning electron microscopy and infrared spectroscopic analysis revealed more porous and looser structures in Monascus pear residue DF (MPDF). Water-, oil-holding, and swelling capacities of MPDF were also enhanced. UV-visible spectral analysis showed that the yield of yellow pigment in Monascus pear residue fermentation broth (MPFB) was slightly higher than that in the Monascus blank control fermentation broth. The citrinin content in MPFB and M. anka seed broth was 0.90 and 0.98 ug/mL, respectively. Therefore, liquid fermentation with M. anka improved the structural and functional properties of MPDF, suggesting its potential as a functional ingredient in food.

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.

Modification, biological activity, applications, and future trends of citrus fiber as a functional component: A comprehensive review

Citrus fiber, a by-product of citrus processing that has significant nutritional and bioactive properties, has gained attention as a promising raw material with extensive developmental potential in the food, pharmaceutical, and feed industries. However, the lack of in-depth understanding regarding citrus fiber, including its structure, modification, mechanism of action, and potential applications is holding back its development and utilization in functional foods and drugs. This review explores the status of extraction methods and modifications applied to citrus fiber to augment its health benefits. With the aim of introducing readers to the potential health benefits of citrus fibers, we have placed special emphasis on their regulatory mechanisms in the context of various conditions, including type 2 diabetes mellitus, cardiovascular disease, obesity, and cancer. Furthermore, this review highlights the applications and prospects of citrus fiber, aiming to provide a theoretical basis for the utilization and exploration of this valuable resource.

Effect of structural characteristics on the physicochemical properties and functional activities of dietary fiber: A review of structure-activity relationship

Dietary fibers come from a wide range of sources and have a variety of preparation methods (including extraction and modification). The different structural characteristics of dietary fibers caused by source, extraction and modification methods directly affect their physicochemical properties and functional activities. The relationship between structure and physicochemical properties and functional activities is an indispensable basic theory for realizing the directional transformation of dietary fibers' structure and accurately regulating their specific properties and activities. In this paper, since a brief overview about the structural characteristics of dietary fiber, the effect of structural characteristics on a variety of physicochemical properties (hydration, electrical, thermal, rheological, emulsifying property, and oil holding capacity, cation exchange capacity) and functional activities (hypoglycemic, hypolipidemic, antioxidant, prebiotic and harmful substances-adsorption activity) of dietary fiber explored by researchers in last five years are emphatically reviewed. Moreover, the future perspectives of structure-activity relationship are discussed. This review aims to provide theoretical foundation for the targeted regulation of properties and activities of dietary fiber, so as to improve the quality of their applied products and physiological efficiency, and then to realize high value utilization of dietary fiber resources.

Changes in the structural, physicochemical and functional properties and in vitro fecal fermentation characteristics of barley dietary fiber fermented by Lactiplantibacillus plantarum dy-1

Fermentation is an effective method for improving the nutritional quality and functional characteristics of grains. This study investigated changes in the structural, physicochemical, and functional properties of fermented barley dietary fiber (FBDF) exerted by Lactiplantibacillus plantarum dy-1 (Lp. plantarum dy-1) as well as its in vitro fecal fermentation characteristics. Lp. plantarum dy-1 fermentation remarkably changed the structure of FBDF, including the microstructure and monosaccharide components, correlating with improved water or oil retaining and cholesterol adsorption capacities. Additionally, Lp. plantarum dy-1 fermentation significantly (p < 0.05) promoted the release of bound phenolics from 6.24 mg g-1 to 6.93 mg g-1 during in vitro digestion, contributing to the higher antioxidant capacity and inhibitory activity of α-amylase and pancreatic lipase compared with those of raw barley dietary fiber (RBDF). A total of 14 phenolic compounds were detected in the supernatants of digestion and fermentation samples. During colonic fermentation, FBDF significantly increased the production of acetate, propionate, and butyrate (p < 0.05), inhibited the growth of Escherichia-Shigella, and promoted the abundance of SCFA-producing microbiota such as Faecalibacterium and Prevotella_9. In conclusion, Lp. plantarum dy-1 fermentation enhanced the physicochemical properties and in vitro fermentation characteristics of barley dietary fiber, representing a promising bioprocessing technology for modifying barley bran.

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.

Effects of two celery fibers on the structural properties and digestibility of glutinous rice starch: A comparative study

The present study focused on the extraction of water-soluble dietary fiber (CSDF) and water-insoluble dietary fiber (CIDF) from celery. It investigated their effects on glutinous rice starch's (GRS) physicochemical, structural, and digestive properties. The results showed that as the addition of the two dietary fibers increased, they compounded with GRS to varying degrees, with the complexing index reaching 69.41 % and 60.81 %, respectively. The rheological results indicated that the two dietary fibers reduced the viscosity of GRS during pasting and inhibited the short-term regrowth of starch. The FTIR and XRD results revealed that the two fibers interacted with GRS through hydrogen bonding, effectively inhibiting starch retrogradation. Furthermore, both fibers increased the pasting temperature of GRS, thus delaying its pasting and exhibiting better thermal stability. Regarding digestibility, the starch gels containing dietary fibers exhibited significantly reduced digestibility, with RS significantly increased by 8.15 % and 8.95 %, respectively. This study provides insights into the interaction between two dietary fibers and GRS during processing. It enriches the theoretical model of dietary fiber-starch interaction and provides a reference for the application development of starch-based functional foods.

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.

Effect of physical treatments on the functional and structural features of soluble dietary fiber from soybean dregs

BACKGROUND

In this research, the effects caused by ultrafine grinding (U), high-temperature cooking (HTC), microwave (M) and combined treatment (U-HTC, U-M) were evaluated on the functional properties and structural characteristics of soluble dietary fiber (SDF) obtained from soybean dregs.

RESULTS

Physical treatments could increase the extraction yield of SDF and improve the functional properties of SDF. The highest extraction yield (277.15 ± 5.87 g kg-1 based on the weight of soybean dregs) and purity (863.37 ± 5.15 g kg-1 based on the extract weight) of SDF was found in the sample by U-M treatment. U-HTC and U-M combined treatments significantly improved the water solubility and oil holding capacity of SDF. U-M treatment significantly increased the ability of SDF to adsorb cholesterol and perform cationic exchange; compared to the control, these abilities were increased by 138.46% and 10.38%, respectively. At pH 2.0, the nitrite ion adsorption capacity (NIAC) of SDF obtained by U-M combined treatment was 184.55 μg g-1 , which was significantly higher by 32.10% compared with that of the control. The results obtained by X-ray diffraction and scanning electron microscopy showed that the structure of SDF generated from soybean dregs became coarser and more porous, and the crystallinity decreased after physical treatments.

CONCLUSION

Combined physical treatment is an effective way to improve the extracted yield and functional properties of SDF from soybean dregs. © 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.

Nutritional, Fatty Acids, (Poly)phenols and Technological Properties of Flower Powders from Fuchsia hybrida and Alcea rosea

Fuchsia hybrida (pena pena) and Alcea rosea L. (malvagoma) are predominant flowers in the "Horchata" infusion, a traditional beverage in southern Ecuador, to which some medicinal properties are attributed. However, there is very little published information about these two flower species. The current study aimed to obtain two dehydrated powders of these flowers and to determine their chemical composition, physicochemical and technological properties, polyphenols, and fatty acids profile. In both powdered flowers, carbohydrates predominated, with a significant content of dietary fiber and fructose. The fat content was low, mainly comprising polyunsaturated fats (62% pena pena and 52% malvagoma), with a significant presence of omega-3 (C18:3n-3,6,9) and omega-6 (C18:2n-6,9) fatty acids, showing a better n-6/n-3 balance in the malvagoma flowers. Pena pena flowers are highlighted by high anthocyanin and ellagic acid amounts, whereas malvagoma contains a high content of flavanones. In conclusion, the studied powder flowers, could be used in the formulation of new foods or as source of anthocyanins as food colorants.

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.

Characterization of Băbească Neagră Grape Pomace and Incorporation into Jelly Candy: Evaluation of Phytochemical, Sensory, and Textural Properties

The influence of particle size intervals (<125 μm, ≥125-<200 μm, and ≥200-<300 μm) of grape pomace (Vitis vinifera var. Băbească Neagră) was analyzed in terms of the proximate composition, functional properties, and physicochemical parameters. The aim was to study the effect of the formulation variables (extract from grape pomace with different particle size intervals and gelatin doses-7, 8.5, and 10 g) on the mechanical properties (hardness, cohesiveness, adhesiveness, springiness, and gumminess), color, and sensorial, microbiological, and phytochemical parameters. The jelly candy formulated with grape pomace extract (<125 μm) and 7 g of gelatin showed the highest total phenolic content (156 mg GAE/g) and antioxidant activity (65.8% inhibition), while grape pomace jellies with a particle size of ≥125-<200 μm and different concentration of gelatin presented the greatest sensory acceptance in terms of sweetness, taste, odor, elasticity, color, and overall acceptability of the resulting jelly. The concluding observation was supported by the microbiological analysis, which also showed that there is no growth in jelly samples except the jelly candies prepared with a ≥200-<300 μm particle size interval of grape pomace extract.

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.

Biovalorization of mango byproduct through enzymatic extraction of dietary fiber

Mango is considered one of the most important tropical fruits worldwide in terms of its consumption and consumer acceptability. Its processing generates huge quantities of mango byproducts, which is often discarded unscrupulously into the environment and, therefore, needs effective waste management practices. The extraction of mango peels' dietary fiber using enzymatic method can be a useful valorization strategy for management of mango by-products. In the present investigation, dietary fiber (soluble and insoluble fraction) was extracted by enzymatic hydrolysis using α-amylase, protease, and amyloglucosidase. Highest yield of dietary fiber (67.5%, w/w) was obtained at 60 °C temperature using recommended enzyme concentrations including α-amylase (40 µL), protease (110 µL), and amyloglucosidase (200 µL) after a treatment time of 60 min. SEM analysis indicated the increased porosity of dietary fiber samples caused due to the hydrolytic effect of enzymes on its surface structure, whereas FTIR analysis confirmed the functional groups present in dietary fiber. The coexistence of crystalline and amorphous nature of polymers present in soluble and insoluble fractions of dietary fiber was assessed by XRD analysis. Further, the analysis of functional properties including WHC, OHC, and SC revealed the suitability of using extracted mango peel's dietary fiber in the food systems.

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.

Effects of Alkaline Hydrogen Peroxide and Cellulase Modifications on the Physicochemical and Functional Properties of Forsythia suspensa Dietary Fiber

Besides active substances, Forsythia suspensa is rich in dietary fiber (DF), but it is often wasted or discarded and not put to good use. In order to improve the function of Forsythia DF, it was modified using alkaline hydrogen peroxide (AHP) and cellulase (EM). Compared to the control DF (ODF), the DF modified using AHP (AHDF) and EM (EMDF) had a looser microstructure, lower crystallinity, and higher oil holding capacity (OHC) and cation exchange capacity (CEC). The AHP treatment significantly increased the water holding capacity (WHC) and water swelling ability (WSA) of the DF, while the EM treatment achieved just the opposite. Moreover, the functional properties of AHDF and EMDF, including their cholesterol adsorption capacity (CAC), nitrite ion adsorption capacity (NAC), glucose adsorption capacity (GAC), glucose dialysis retardation index (GDRI), α-amylase inhibitory activity, and DPPH radical scavenging activity, were far better than those of ODF. Together, the results revealed that AHP and EM modifications could effectively improve or enhance the physicochemical and functional properties of Forsythia suspensa DF.

Relationship between Physicochemical, Techno-Functional and Health-Promoting Properties of Fiber-Rich Fruit and Vegetable By-Products and Their Enhancement by Emerging Technologies

The preparation and processing of fruits and vegetables produce high amounts of underutilized fractions, such as pomace and peel, which present a risk to the environment but constitute a valuable source of dietary fiber (DF) and bioactive compounds. The utilization of these fiber-rich products as functional food ingredients demands the application of treatments to improve their techno-functional properties, such as oil and water binding, and health-related properties, such as fermentability, adsorption, and retardation capacities of glucose, cholesterol, and bile acids. The enhancement of health-promoting properties is strongly connected with certain structural and techno-functional characteristics, such as the soluble DF content, presence of hydrophobic groups, and viscosity. Novel physical, environmentally friendly technologies, such as ultrasound (US), high-pressure processing (HPP), extrusion, and microwave, have been found to have higher potential than chemical and comminution techniques in causing desirable structural alterations of the DF network that lead to the improvement of techno-functionality and health promotion. The application of enzymes was related to higher soluble DF content, which might be associated with improved DF properties. Combined physical and enzymatic treatments can aid solubilization and modifications, but their benefit needs to be evaluated for each DF source and the desired outcome.

Polysaccharide-based biosorbents for cholesterol and bile salts in gastric-intestinal passage: Advances and future trends

Cholesterol is one of the hazard elements for many cardiovascular diseases, but many cholesterol-lowering drugs are expensive and unhealthy. Therefore, it is necessary to develop edible and safe biosorbents to reduce excess cholesterol and bile salts in the gastric-intestinal passage. Polysaccharide-based biosorbents offer a feasible strategy for decreasing them. This review summarized polysaccharide-based biosorbents that have been developed for adsorbing cholesterol and bile salts from the gastric-intestinal passage and analyzed common modification methods for these adsorbents. Finally, the adsorption models were also elucidated. Polysaccharides, including β-cyclodextrin, pectin, chitin/chitosan, dietary fiber extract, and cellulose, have been proposed for adsorbing cholesterol and bile salts in the gastric-intestinal passage as biosorbents. This is mainly due to the retention of pores, the capture of the viscosity network, and the help of hydrophobic interactions. In spite of this, the adsorption capacity of polysaccharides is still limited. Therefore, the modifications for them became the most popular areas in the recent studies of in vitro cholesterol adsorption. Chemical approaches namely grafting, (1) acetylation, (2) hydroxypropylation, (3) carboxymethylation, and (4) amination are considered to modify the polysaccharides for higher adsorption ability. Moreover, ultrasonic/microwave/pressure treatment and micron technology (microfluidization, micronization, and ball milling) are effective physical modification methods, while the biological approach mainly refers to enzymatic hydrolysis and microbial fermentation. The adsorption models are generally explained by two adsorption isotherms and two adsorption kinetics. In sum, it is reckoned that further food applications will follow soon.

Dietary fiber extraction from citrus peel pomace: Yield optimization and evaluation of its functionality, rheological behavior, and microstructure properties

Citrus fruits were widely used in processing and production, generating a large amount of peel pomace and a low utilization rate, resulting in substantial economic losses and environmental risks. It was important to extract compounds from citrus peel pomaces and find suitable preparation methods to improve their yield and physicochemical properties. Grapefruit peel pomace (GP) and navel orange peel pomace (OP) were used as raw materials in this study to prepare green and edible soluble dietary fiber (SDF) and insoluble dietary fiber (IDF). Analysis was done on the effects of solid-liquid ratio, cellulase hydrolysis time, cellulase dosage, and ultrasonic time on dietary fiber (DF) yield. To obtain the best DF preparation conditions, we used range analysis, variance analysis, and orthogonal experimental design. We also analyzed the structural, physicochemical, and rheological characteristics of SDF and IDF. According to the study's findings, SDF and IDF showed a loose and expansive structure with reduced particle size, higher specific surface area, and noticeably better physical and chemical properties after treating GP and OP with ultrasound-assisted composite enzyme method. Both SDF solution and IDF suspension were discovered through rheological analysis to be non-Newtonian pseudoplastic fluids, which was advantageous for expanding their applications in the field of food packaging. In conclusion, DF prepared using the ultrasound-assisted composite enzyme method was an excellent source of edible packaging materials, offering a benchmark for the recycling of other citrus peel wastes and ultimately paving the way for new methods of recycling citrus waste.

Effects of three biological combined with chemical methods on the microstructure, physicochemical properties and antioxidant activity of millet bran dietary fibre

The effects of cellulase hydrolysis separately combined with hydroxypropylation, carboxymethylation and phosphate crosslinking on the physicochemical properties and antioxidant activity of millet bran dietary fibre (MBDF) were investigated. Compared to cellulase hydrolysis alone, these dual modifications more effectively improved the soluble fibre content, water-swelling ability, viscosity, emulsifying capacity and cation-exchange capacity of MBDF but reduced the emulsion stability, brightness and polyphenol content of MBDF (P < 0.05). MBDF modified by cellulase hydrolysis combined with hydroxypropylation showed the highest emulsifying capacity (60.03 m²/g) and oil-adsorption capacity (3.32 g/g) but the lowest nitrite ion-adsorbing ability (NIAA). MBDF modified by cellulase hydrolysis with carboxymethylation showed the highest surface hydrophobicity, cation-exchange capacity (0.352 mmol/g) and NIAA (152.89 μg/g). MBDF modified by cellulase hydrolysis combined with phosphate crosslinking exhibited excellent copper ion-adsorbing ability (19.97 mg/g) and viscosity (19.33 cp). Moreover, these dual modifications all enhanced the Fe²⁺ chelating ability and reducing power of MBDF (P < 0.05).

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.

Effect of Insoluble Dietary Fiber Extracted from Feijoa (Acca sellowiana (O. Berg) Burret.) Supplementation on Physicochemical and Functional Properties of Wheat Bread

This study aimed to assess the effects of insoluble dietary fiber (IDF) from feijoa supplementation on the physicochemical and functional properties of wheat bread. The results showed that feijoa IDF (FJI) had the typical structures of hydrolysis fiber, polysaccharide functional groups, and crystal structure of cellulose. The gradual increase of FJI levels (from 2 to 8%) in wheat bread resulted in increased total DF, ash, and protein contents, accompanied by a reduction in moisture, carbohydrates, and energy value. The inclusion of FJI in the bread crumb caused a rise in both redness (a*) and yellowness (b*) values while decreasing the brightness (L*) relative to the control specimen. In addition, adding FJI up to 2% significantly increased total phenolic and flavonoid contents and antioxidant activity, as well as flavor score of supplemented bread samples, while additions above 2% resulted in undesirable taste and texture. FJI addition caused higher bile acid, NO^2-, and cholesterol adsorption capacities. Moreover, FJI addition up to 4% significantly reduced glucose adsorption capacities at different in vitro starch digestion intervals. The findings revealed that FJI offers great potential as an ideal functional ingredient in food processing.

Dietary Fiber from Navel Orange Peel Prepared by Enzymatic and Ultrasound-Assisted Deep Eutectic Solvents: Physicochemical and Prebiotic Properties

Dietary fiber (DF) was extracted from navel orange peel residue by enzyme (E-DF) and ultrasound-assisted deep eutectic solvent (US-DES-DF), and its physicochemical and prebiotic properties were characterized. Based on Fourier-transform infrared spectroscopy, all DF samples exhibited typical polysaccharide absorption spectra, indicating that DES could separate lignin while leaving the chemical structure of DF unchanged, yielding significantly higher extraction yields (76.69 ± 1.68%) compared to enzymatic methods (67.27 ± 0.13%). Moreover, ultrasound-assisted DES extraction improved the properties of navel orange DFs by significantly increasing the contents of soluble dietary fiber and total dietary fiber (3.29 ± 1.33% and 10.13 ± 0.78%, respectively), as well as a notable improvement in the values of water-holding capacity, oil-holding capacity, and water swelling capacity. US-DES-DF outperformed commercial citrus fiber in stimulating the proliferation of probiotic Bifidobacteria strains in vitro. Overall, ultrasound-assisted DES extraction exhibited potential as an industrial extraction method, and US-DES-DF could serve as a valuable functional food ingredient. These results provide a new perspective on the prebiotic properties of dietary fibers and the preparation process of prebiotics.

Fermentation of grapefruit peel by an efficient cellulose-degrading strain, (Penicillium YZ-1): Modification, structure and functional properties of soluble dietary fiber

In the study, a highly efficient cellulose-degrading strain was screened, which was identified as a fungus in the genus Penicillium sp., named YZ-1. The content of soluble dietary fiber was greatly increased by the treatment of this strain. In addition, the effects of soluble dietary fiber from high-pressure cooking group (HG-SDF), strain fermentation group (FG-SDF) and control group (CK-SDF) on the physicochemical structure, and in vitro hypolipidemic activity were investigated. The results showed that the physicochemical structure of the raw materials was improved after fermentation, and FG-SDF exhibited the loosest structure, the highest viscosity and thermal stability. Furthermore, compared to CK-SDF and HG-SDF, FG-SDF showed the most significant improvement in functional properties, including cholesterol adsorption capacity (CAC), inhibition of pancreatic lipase activity (LI) and mixed bile acid adsorption capacity (BBC). Overall, these findings will provide new insights into dietary fiber modification and improve the comprehensive use value of grapefruit by-products.

Effects of particle size on the structure, cooking quality and anthocyanin diffusion of purple sweet potato noodles

The effects of different particle sizes of purple sweet potato flour (PSPF) on the structure and quality of noodles and the diffusion kinetics of anthocyanins during cooking were studied. As the particle size of the PSPF decreased (from 269 to 66 μm), the adverse effects of the addition of PSPF on the quality of noodles were reduced. The smaller particle size of PSPF was beneficial for the secondary structure orderliness and the tighter microstructure of PSP noodles. The diffusion of anthocyanins in noodles to the soup during cooking could be fitted well with Fick's second law, and diffusion coefficients were in the range of 8.3248-14.0893 × 10^-9 m²/s. The noodles with 15% 66 μm PSPF showed the best cooking properties, the highest sensory score, the highest anthocyanin retention ability and a compact and orderly microstructure. Thus, they could be considered as noodles rich in anthocyanins for commercial application.

Effects of Highland Barley Flour with Different Particle Sizes on the Characteristics of Reconstituted Flour and Noodles

To study the effects of highland barley flour with different particle sizes on dough characteristics and noodle quality, highland barley flours (median particle sizes of 223.25, 143.12, 90.73, 42.33 and 19.26 μm, respectively) were mixed with the wheat flour to make noodles. The damaged starch content of highland barley flour with five particle sizes was 47.0, 61.0, 62.3, 102.0, and 108.0 g/kg, respectively. The reconstituted flour containing highland barley powder with smaller particle sizes showed higher viscosity and water absorption. The smaller the particle size of barley flour, the lower the cooking yield, shear force and pasting enthalpy of the noodles, and the higher the hardness of the noodles. As the particle size of barley flour decreases, the structural density of the noodles increases. This study is expected to provide a constructive reference for the development of barley-wheat composite flour and the production of barley-wheat noodles.

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.

Structure characteristics and physicochemical property of starch, dietary fiber, protein in purple corn flour modified by low temperature impact mill

The structural changes of macromolecules (starch, dietary fiber and protein) in purple corn flour (PCF) modified by a low temperature impact mill (LTIM) at different air classifier speed (ACS) were investigated. LTIM changed the multi-scale structure of starch, which was characterized by increased starch damage, stronger destruction of relative crystallinity (from 37.85 % to 15.53 %) and short-range ordered structure (R_1047/1022, from 1.21 to 0.73) with the increased ACS. The structure of dietary fiber was also destroyed on multi-level, including decreased particle size, destructive morphology, and slightly changed crystalline structure. Additionally, LTIM showed high damage on the senior structure (surface hydrophobicity, disulfide bond, secondary structure) of protein. Due to the structure changes modified by LTIM, starch, dietary fiber and protein played different role on hydration property of PCF. Starch had positive effect, while dietary fiber and protein had negative effect. Our experimental results may provide valuable information for further analysis of other quality changes (oil holding capacity, cation exchange capacity, ability to produce high-quality dough or end-out products, etc.) of purple corn flour after LTIM treatment.

Influences of Particle Size and Addition Level on the Rheological Properties and Water Mobility of Purple Sweet Potato Dough

This paper investigated the effects of different particle sizes and addition levels of purple sweet potato flour (PSPF) on the rheological properties and moisture states of wheat dough. There was deterioration in the pasting and mixing properties of the dough, due to the addition of PSPF (0~20% substitution), which was reduced by decreasing the particle size of the PSPF (260~59 μm). Dynamic rheology results showed that PSPF enhanced the elasticity of the dough, providing it solid-like processability. PSPF promoted the binding of gluten proteins and starch in the dough, resulting in a denser microstructure. Differential scanning calorimetry and low-field nuclear magnetic resonance showed that PSPF converted immobilized water and freezable water to bound water and non-freezable water in the dough, making the dough more stable, and that the reduction in PSPF particle size facilitated these processes. Our results provide evidence for the great application potential of purple sweet potatoes for use in flour-based products.

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.

Effects of shear emulsifying/ball milling/autoclave modification on structure, physicochemical properties, phenolic compounds, and antioxidant capacity of lotus (Nelumbo) leaves dietary fiber

Lotus (Nelumbo) leaves are rich in polyphenols and dietary fiber, which have the potential as a high-quality fiber material in functional food. However, lotus leaves exhibit dense structure and poor taste, it is vital to develop appropriate modification methods to improve the properties of lotus leaves dietary fiber. In this study, the effects of three modification methods with shear emulsifying (SE), ball milling (BM), and autoclave treatment (AT) on structure, physicochemical properties, phenolic compounds, and antioxidant capacity of lotus leave dietary fiber (LDF) were evaluated. SEM indicated that there were significant differences in the microstructure of modified LDFs. FT-IR spectra and X-ray diffraction pattern of modified LDFs revealed similar shapes, while the peak intensity and crystalline region changed by modification. SE showed the greatest effect on crystallization index. SE-LDF had the highest water holding capacity, water swelling capacity, and bound phenolic content in LDFs, which increased by 15.69, 12.02, and 31.81%, respectively, compared with the unmodified LDF. BM exhibited the most dramatic effect on particle size. BM-LDF had the highest free phenolic and total phenolic contents in LDFs, which increased by 32.20 and 29.05% respectively, compared with the unmodified LDF. Phenolic compounds in LDFs were mainly free phenolic, and modifications altered the concents of flavonoids. The BM-LDF and SE-LDF exhibited higher antioxidant capacity than that of AT-LDF. Overall, SE-LDF showed better physical properties, and BM-LDF showed better bioactive components. SE and BM were considered to be appropriate modification methods to enhance the properties of LDF with their own advantages.

The Sustainability of Sweet Potato Residues from Starch Processing By-Products: Preparation with Lacticaseibacillus rhamnosus and Pediococcus pentosaceus, Characterization, and Application

The effects of Lacticaseibacillus rhamnosus and Pediococcus pentosaceus on the nutritional-functional composition, structure, in vitro saliva-gastrointestinal digestion, and colonic fermentation behaviors of fermented sweet potato residues (FSPR) were investigated. The FSPR was obtained under the condition of a solid-to-liquid ratio of 1/10, inoculation quantity of 1.5%, mixed bacteria ratio 1:1, fermentation time of 48 h, and fermentation temperature of 37 °C. The FSPR showed higher contents of soluble dietary fiber (15.02 g/100 g), total polyphenols content (95.74 mg/100 g), lactic acid (58.01 mg/g), acetic acid (1.66 mg/g), volatile acids (34.26%), and antioxidant activities. As exhibited by FTIR and SEM, the higher peak intensity at 1741 cm^-1 and looser structure were observed in FSPR. Further, the FSPR group at colonic fermentation time of 48 h showed higher content of acetic acid (1366.88 µg/mL), propionic acid (40.98 µg/mL), and butyric acid (22.71 µg/mL), which were the metabolites produced by gut microbiota using dietary fiber. Meanwhile, the abundance of Bifidobacterium and Lacticaseibacillus in the FSPR group was also improved. These results indicated that FSPR potentially developed functional foods that contributed to colonic health.

Micronization Effects on Structural, Functional, and Antioxidant Properties of Wheat Bran

To explore the effect of micronization on the structural, functional, and antioxidant properties of wheat bran, wheat bran with mean particle size (D₅₀) of 46.08, 34.29, 26.51, 26.35, and 26.05 μm were prepared by using an ultrafine pulverizer under different rolling frequencies (0, 6, 9, 12, and 15 times). The main chemical components and structural, functional, and antioxidant properties of the wheat bran were compared and a correlation analysis was conducted. As the D₅₀ of the wheat bran decreased from 46.08 μm to 26.05 μm, the micromorphology exhibited the destruction of the bundle structure, which is formed by starch and fiber, during which the starch particles peeled off, the fiber fragments destructed, and some of the slim fiber fragments attached to the surfaces of the starch granules. According to the X-ray diffraction pattern, part of the crystalline structure was transformed into an amorphous structure and the crystallization index decreased from 13.08% to 3.95%. According to the near-infrared spectrum, more active groups, such as the hydroxyl group, were exposed; however, no new groups were generated. These structural changes accordingly caused changes in the chemical components, functional properties, and antioxidant properties of the wheat bran. Specifically, the protein, total phenols, total flavonoids, and fatty acid content increased by 6.72%, 23.47%, 19.07%, and 172.88%, respectively. The lipase activity, antioxidant activity in vitro (DPPH• scavenging activity, ABTS⁺• scavenging activity, and ferric reducing antioxidant power), and the water-holding, cholesterol-adsorption, sodium nitrite-adsorption, and cation-exchange capacities, were enhanced to some extent. The oil-holding capacity decreased from 3.01 g/g to 1.32 g/g. The swelling capacity decreased first and then increased and the swelling capacity of the wheat bran with a D₅₀ of 34.29 μm was the lowest (3.62 mL/g). Therefore, the micronization could be used as a pretreatment method to improve the functional and antioxidant properties of wheat bran; however, the optimal particle size of wheat bran is based on the function of the product.

Physicochemical Characteristics of Soluble Dietary Fiber Obtained from Grapefruit Peel Insoluble Dietary Fiber and Its Effects on Blueberry Jam

Appropriate modification methods can increase the proportion of soluble dietary fiber (SDF). In this study, grapefruit peel insoluble dietary fiber (GP-IDF) was modified with the combined microwave and enzymatic method to obtain SDF. With regard to structural characterization, SDF from grapefruit peel IDF (GP-IDF-SDF) presented as a flat sheet with cracks, composed of a typical cellulose type I crystal, and had good stability below 200 °C. Galacturonic acid, arabinose and glucuronic acid were the main monosaccharide compositions, indicating that pectin might have been the principal component. Moreover, GP-IDF-SDF was excellent in water retention capacity (13.43 ± 1.19 g/g), oil retention capacity (22.10 ± 0.85 g/g) and glucose adsorption capacity (14.49 ± 0.068 mg/g). Thereafter, the effects of GP-IDF-SDF and commercial pectin addition on the color, rheology, texture and sensory properties of blueberry jam were compared. The results showed that the color of jam with GP-IDF-SDF was lighter. The addition of GP-IDF-SDF had less effects on the viscosity and gel strength of jam, but it enhanced the stability of jam. According to sensory data, the color, texture and spreadability of jam with GP-IDF-SDF or pectin were improved and more acceptable. Overall, GP-IDF-SDF had functional characteristics and played a positive role in jam, and it is expected to be a candidate for the development of functional food ingredients.

Comparison of different extraction methods on the physicochemical, structural properties, and in vitro hypoglycemic activity of bamboo shoot dietary fibers

The effect of alkali extraction (AE), enzymatic extraction (EE), ultrasonic-assisted enzymatic extraction (UAEE), and shear homogeneous-assisted enzymatic extraction (SHAEE) on the physicochemical, structural properties, and in vitro hypoglycemic activity of bamboo shoot dietary fibers (BSDF) were investigated and compared. BSDF obtained by AE had the lowest protein content and crystallinity index. The lowest oil holding capacity (OHC) and highest protein content were observed in EE. BSDF generated highest OHC and glucose adsorption capacity by UAEE. SHAEE obtained the highest SDF content (17.89%), water-holding capacity (8.81 g/g), and α-amylase activity inhibition ratio (19.89%) and the smallest particle size (351.33 μm). BSDF extracted by SHAEE and UAEE presented a porous and loose structure. Furthermore, the in vitro hypoglycemic activity of the four BSDF samples generally followed the order of SHAEE > UAEE > EE > AE. Results show that SHAEE is an innovative and promising method to obtain BSDF with its excellent physicochemical and functional properties.

Technological Properties and Composition of Enzymatically Modified Cranberry Pomace

Cranberry pomace obtained after juice production is a good source of dietary fiber and other bioactive compounds. In this study, cranberry pomace was hydrolyzed with Viscozyme® L, Pectinex® Ultra Tropical, Pectinex® Yieldmash Plus, and Celluclast® 1.5L (Novozyme A/S, Denmark). The soluble and insoluble dietary fiber was determined using the Megazyme kit, while the changes in mono-, disaccharide and oligosaccharides’ contents were determined using HPLC-RI; the total phenolic contents were determined by Folin−Ciocalteu’s Assay. Prebiotic activity, using two probiotic strains Lactobacillus acidophilus DSM 20079 and Bifidobacterium animalis DSM 20105, was investigated. The technological properties, such as hydration and oil retention capacity, were evaluated. The enzymatic treatment increased the yield of short-chain soluble saccharides. The highest oligosaccharide content was obtained using Viscozyme® L and Pectinex® Ultra Tropical. All of the tested extracts of cranberry pomace showed the ability to promote growth of selected probiotic bacteria. The insoluble dietary fiber content decreased in all of the samples, while the soluble dietary fiber increased just in samples hydrolyzed with Celluclast® 1.5L. The highest content of total phenolic compounds was obtained using Viscozyme® L and Pectinex® Ultra Tropical (10.9% and 13.1% higher than control, respectively). The enzymatically treated cranberry pomace exhibited lower oil and water retention capacities in most cases. In contrast, water swelling capacity increased by 23% and 70% in samples treated with Viscozyme® L and Celluclast® 1.5L, respectively. Enzymatically treated cranberry pomace has a different composition and technological properties depending on the enzyme used for hydrolysis and can be used in various novel food products.