Phenolic profile and in vitro antioxidant capacity of insoluble dietary fiber powders from citrus (Citrus junos Sieb. ex Tanaka) pomace as affected by ultrafine grinding

Effects of Grinding Methods of Tartary Buckwheat Leaf Powder on the Characteristics and Micromorphology of Wheat Dough

The functional components in tartary buckwheat leaf powder can give flour products higher nutritional value. To comprehensively realize the high-value utilization of tartary buckwheat and its by-products, electric stone mill powder (EMP), ultra-fine mill powder (UMP), steel mill powder (SMP), and grain mill powder (GMP) from tartary buckwheat leaves were used in the preparation of wheat dough, and this was used to explore their effects on dough properties and protein microstructure. With an increase in tartary buckwheat leaf powder, the hydration characteristics, protein weakening rate, and starch gelatinization characteristics of the dough changed, and the water holding capacity and swelling capacity decreased. The retrogradation value increased, which could prolong the shelf life of related products. The water solubility of the dough showed an upward trend and was the lowest at 10% UMP. The addition of UMP produced a more uniform dough stability time and the lowest degree of protein weakening, which made the dough more resistant to kneading. An increasing amount of tartary buckwheat leaf powder augmented the free sulfhydryl content of the dough and decreased the disulfide bond content. The disulfide bond content of the dough containing UMP was higher than that of the other doughs, and the stability of the dough was better. The peaks of the infrared spectrum of the dough changed after adding 10% UMP and 20% EMP. The content of α-helical structures was the highest at 10% UMP, and the content of ordered structures was enhanced. The polymerization of low molecular weight proteins to form macromolecular polymers led to a reduction in surface hydrophobic regions and the aggregation of hydrophobic groups. The SEM results also demonstrated that at 10% tartary buckwheat leaf powder, the addition of UMP was significantly different from that of the other three leaf powders, and at 20%, the addition of EMP substantially altered the structure of the dough proteins. Considering the effects of different milling methods and different added amounts of tartary buckwheat leaf powder on various characteristics of dough, 10% UMP is the most suitable amount to add to the dough.

Fabrication and characterization of dual-functional porous starch with both emulsification and antioxidant properties

Starchy materials with good antioxidant, emulsification and adsorption properties have potential applications in industry. To improve these properties, a Dual-functional porous starch was prepared through one-pot synthesis. In this case, octenyl succinic anhydride (OSA) and syringic acid (SA) were selected to modify the porous starch (PS) by esterification, with subsequent signals recorded by 1H NMR at 1.2 ppm and FT-IR at 1743 cm-1, indicating the formation of Dual-functional porous starch grafted by OSA and SA. N2 adsorption analysis further proved that the porous structure (2.9 m2g-1) was still maintained after modification. This was followed by measurements of droplet size distribution (34.18 ± 3.80 μm), zeta potential (-39.62 ± 1.89 mV) and emulsion index (85.10 ± 1.76 %), all of which indicated good emulsifying capacity. Meanwhile, results of radical scavenging assay proved that the Dual-functional porous starch had considerable antioxidant properties due to the introduction of SA groups. Besides, the Dual-functional porous starch also showed good resistance to digestion. These findings not only provide a novel strategy for constructing multi-functionalized starchy materials, but also open up potential applications of starch in the food and pharmaceutical industries.

Tailoring the composition, antioxidant activity, and prebiotic potential of apple peel by Aspergillus oryzae fermentation

Apple peel is a typical lignocellulosic food by-product rich in functional components. In this work, apple peel was solid-state fermented with Aspergillus oryzae with an aim to modulate its composition and bioactivity. The results showed that A. oryzae fermentation substantially tailored the composition, improved the antioxidant activity and prebiotic potential of apple peel. Upon the fermentation, 1) free phenolics increased and antioxidant activity improved; 2) the pectin substances degraded significantly, along with a decrease in soluble dietary fiber while an increase in insoluble dietary fiber; 3) the in vitro fermentability increased as indicated by the increase in total acid production. The gut microbiota was shaped with more health-promoting potentials, such as higher abundances of Lactobacillus, Bifidobacterium, Megamonas and Prevotella-9 as well as lower abundances of Enterobacter and Echerichia-Shigella. This work is conducive to the modification of apple peel as a potential ingredient in food formulations.

Probing covalent and non-covalent interactions between vanillic acid and starch and their effects on digestibility by solid-state NMR

Intermolecular interactions play a significant role on the physicochemical properties and digestibility of starchy foods. This study investigated the covalent and non-covalent interactions between vanillic acid (VA) and porous starch (PS) as well as their effects on digestibility using solid-state NMR. VA-PS conjugates and mixtures were synthesized and characterized using 1H NMR, FT-IR, SEM and XRD. 13C NMR peaks at 163 ppm and FT-IR signals at 1737 cm-1 indicated the formation of ester bond in VA-PS conjugates. While differences between covalent and non-covalent interactions were also probed by solid-state NMR. The specific binding sites between VA and PS were subsequently identified by 1H13C HETCOR spectra before assessing the impact of covalent and non-covalent interactions on digestibility through an in vitro digestion test. The results revealed 13C chemical shifts of about 2.0 ppm, indicating stronger intermolecular interactions, and reduced mobility of the VA-PS conjugate due to its covalent bonding. Overall, the results showed that the VA-PS conjugate, characterized by stronger covalent interactions, exhibited superior effects in inhibiting starch digestibility compared with non-covalent interactions.

Insight into structure-activity relationships of hydroxycinnamic acids modified porous starch: The effect of phenolic hydroxy groups

Antioxidant capacity of hydroxycinnamic acids-modified starch mainly depends on their chemical structure. Herein, cinnamic acid as well as meta-substituted and para-substituted cinnamic acid were selected for esterification with porous starch (labelled as CA@PS, m-CA@PS and p-CA@PS), with the successful formation of porous starch (labelled as PS) esters then confirmed by ¹H NMR, ¹³C solid-state NMR and FT-IR spectroscopy. Three PS esters with almost same degrees of substitution (DS) were obtained, and antioxidant assays, including DPPH radical scavenging, reducing power and hydroxyl radical scavenging tests, were subsequently used to evaluate the antioxidant activity of the esterified PS. Overall, CA@PS showed weak antioxidant activity because of the absence of phenolic hydroxy, while p-CA@PS displayed better antioxidant capacity. Because its conjugated structure offered the stronger electron-donating effect, that could enhance antioxidant capacity. Therefore, antioxidant capacity depended significantly on overall chemical structure, including numbers and substitution positions of phenolic hydroxy groups.

Effect of particle size on composition, physicochemical, functional, and structural properties of insoluble dietary fiber concentrate from citrus peel

To investigate the composition, physicochemical, functional, and structural properties of citrus insoluble dietary fiber concentrate from citrus peel affected by different particle sizes, citrus insoluble dietary fiber concentrate was modified by coarse crush and superfine grinding treatments. The results showed that the contents of hemicellulose and lignin significantly decrease and a significant increase in cellulose and insoluble dietary fiber contents with the reduction in particle size. In addition, the markedly decreased particle size and obviously microstructural changes of citrus insoluble dietary fiber concentrate powder were observed. The color value of citrus insoluble dietary fiber concentrate was observably improved, crystallinity and thermal stability of modified fiber slightly increase with the decrease in particle size, which is due to the partial elimination of hemicellulose and lignin after the treatments. However, water holding capacity, water swelling capacity, and oil holding capacity were found to be lower with the reduction in particle size, which might be attributed to the fact that superfine grinding treatment destroyed the structure integrity, thus causing some soluble components to break away from the cellulose backbone, or due to aggregation of smaller granules. The present study suggested that decreasing the particle size could effectively change some properties of citrus insoluble dietary fiber concentrate, which will provide new perspectives for the application of citrus insoluble dietary fiber concentrate in food products.

Bioavailability of Bioactive Compounds from Reconstituted Grapefruit Juice as Affected by the Obtention Process

Much attention has been paid to the health benefits of including fruits and vegetables in the diet. However, for the compounds responsible for this beneficial effect to be effective at the level of the human organism, they must be available for absorption after digestion. In this sense, in vivo studies are needed to demonstrate the bioavailability of these compounds and their physiological activity. In order to provide information in this regard, this study collects data on the levels of vitamin C (VC) and naringenin (NAG) in the blood serum of the 11 volunteer participants in this trial, before and after consuming two different grapefruit juices. The juices were prepared by rehydrating the grapefruit powder obtained by freeze-drying (FD) the fruit puree or by spray-drying (SD) the liquefied grapefruit. No significant differences (p > 0.05) neither by juice nor by participant were observed in any case. The mean relative increase of VC, NAG and the radical scavenging ability (RSA) in blood serum due to grapefruit juices intake was 12%, 28% and 26%, respectively. Just VC showed a positive and significant Pearson's correlation with RSA. The mean bioavailability of VC was quantified as 1.529 ± 0.002 mg VC/L serum per 100 mg of VC ingested.

Fruit pomaces-their nutrient and bioactive components, effects on growth and health of poultry species, and possible optimization techniques

The ever-growing human population, coupled with the exigent need to meet the increasing demand for poultry meat and egg, has put the onus on poultry nutritionists and farmers to identify alternative feed ingredients that could assure the least-cost feed formulation. In addition, the public desire for non-antibiotic-treated poultry products has also necessitated the ultimate search for potent antibiotic alternatives for use in poultry production. While some identified alternatives are promising, their cost implications and technical know-how requirements may discourage their ease of adoption in poultry. The use of plants and/or their by-products, like fruit pomaces, present a pocket-friendly advantage and as a result, are gaining much interest. This is traceable to their rich phytochemical profile, nutritional composition, ready availability, and relatively cheap cost. The fruit juice and wine pressing industries generate a plethora of fruit wastes annually. Interestingly, fruit pomaces contain appreciable dietary fibre, protein, and phenolic compounds, and thus, their adoption could serve the poultry industry in dual capacities including as substitutes to antibiotics and some conventional feedstuff. Thus, there is a possibility to reduce fruit wastes produced and feed-cost in poultry farming from environmental and economical standpoints, respectively. This review seeks to provide reinforcing evidence on the applicability and impact of fruit pomaces in poultry nutrition.

Construction of ferulic acid modified porous starch esters for improving the antioxidant capacity

For exploration of a type of synthetic antioxidant dietary fiber (ADF), porous starch (PS), modified by esterification with ferulic acid (FA) moieties, was synthesized successfully, with different degree of substitution (DS). The ester linkage of FA modified PS was confirmed by ¹³C solid-state NMR and FT-IR. XRD analysis showed that starch ferulates had a different crystal structure from the V-type pattern of native starch, suggesting that the starch gelled during the esterification reaction, then re-crystallized into a different structure. Morphological studies revealed that FA modified PS esters had a different morphology of irregular beehive-like and dense fibrous-like structures compared with that of native starch. In vitro antioxidant assays showed that starch ferulates had excellent antioxidant capacity. In particular, FA modified PS esters had a much higher antioxidant capacity than free FA in the β-carotene–linoleic acid assay. This study has advanced the technology of using porous starches for modifying the biological activity of an antioxidant polyphenol. We expect this work would inspire further studies on the interactions of phenolics with other food ingredients in the food industry.

For exploration of a type of synthetic antioxidant dietary fiber (ADF), porous starch (PS), modified by esterification with ferulic acid (FA) moieties, was synthesized successfully, with different degree of substitution (DS).

Effect of different superfine grinding technologies on the physicochemical and antioxidant properties of tartary buckwheat bran powder

The effect of shear crushing, airflow comminution, and wet grinding on the physical and chemical properties of Tartary buckwheat bran (TBB) powder was compared. Superfine grinding significantly reduces the particle size of bran (1.644 μm), while increasing the protein content (23.60%), water-holding capacity (4.38 g g^-1), solubility (21.077 g 100 g^-1), bulk density (0.34 g mL^-1), and tap density (0.53 g mL^-1) providing good processing characteristics. The antioxidant properties of bran powder prepared by the three methods mentioned above were compared. The results showed that different bran powders subjected to superfine grinding displayed varying levels of antioxidant capacity. The quercetin content (2.18 g 100 g^-1) of the wet-grinding bran powder (WGBP) was twice that of the control group, while no rutin was detected. The total flavonoid content (TFC) and total phenolic content (TPC) were significantly different from those of other groups. The DPPH, ˙OH, and ABTS⁺ removal rates were 60.74%, 86.62%, and 92.98%, respectively, while that of ˙OH was significantly higher than in the other treatment groups. The control group, shear crushed, and airflow comminution bran exhibited no significant differences in TFC, TPC, and oxidation resistance, except for the ability to remove ˙OH. TBB powder obtained via superfine grinding displayed superior taste and functional characteristics, providing a theoretical reference for the processing of this bran.

The environmental impacts of citrus residue management in China: A case study in The Three Gorges Reservoir Region

This study conducted the first life cycle analysis for citrus residue (CR) management systems in China. The results indicated conventional waste treatment systems were not suitable for CR management in China. Although feed system seems to be a favourable option, the uncertainty analysis suggested valorisation system could achieved better performance in global warming, eutrophication and human toxicity. The environmental impacts of valorisation systems were more sensitive to energy consumption. For silage and single cell protein (SCP) system, the environmental impacts could be significantly reduced by improving the energy use efficiency or using more renewable energy. In comparison, although the environmental impacts of biorefinery system were less favourable than SCP and silage systems. The multiple extraction unit had less impact than reported values in other studies. Further research in biorefinery system can focus on increasing the energy efficiency of pre-treatment or reuse of extraction chemicals.

Modification of pea dietary fiber by ultrafine grinding and hypoglycemic effect in diabetes mellitus mice

This study was designed to investigate the effects of ultrafine grinding on the physicochemical properties of pea dietary fiber (PDF) and the hypoglycemic effect of ultrafine grinding dietary fiber on diabetes mellitus (DM). So, the PDF was treated by ultrafine grinding technology, and its microstructure and physicochemical properties were determined. Then, the DM model was established, and the 4-week ultrafine grinded pea dietary fiber (UGPDF) diet intervention was conducted by using gavage and feeding. During this period, the blood glucose and body weight of the mice were measured, and an oral glucose tolerance test was measured on the last day. The biochemical blood indexes of the mice were determined, and the pancreas was stained with HE after dissecting. The results showed that after ultrafine grinding, the structure fragmentation, specific surface area increased, and UGPDF showed higher swelling ability as well as water and oil holding capacities. Simultaneously, UGPDF had a significant effect on reducing blood glucose and glycosylated hemoglobin in DM mice, improving the wasting state of mice and increasing the tolerance to glucose. Further, the results of the HE section showed that the pancreatic islet cells gradually returned to normal regular morphology. In biochemical blood indicators, UGPDF reduced TC and TG levels in the blood. This study provided a specific data basis for the following research on the hypoglycemic mechanism, and broadens the application field of PDF. PRACTICAL APPLICATION: The physicochemical properties of pea dietary fiber were improved by ultrafine grinding technology. Because of this, the application of pea dietary fiber in the field of hypoglycemic had a better effect, laying a foundation for the next research on hypoglycemic mechanism.

Leading individual features of antioxidant systematically classified by the ORAC assay and its single electron transfer and hydrogen atom transfer reactivities; analyzing ALS therapeutic drug Edaravone

Many natural compounds mop up radicals and limit radical reactions and may prove useful in reducing or preventing oxidative stress-related diseases in vivo. Several assays have been developed to measure antioxidant or anti-radical activity. Here, we measured the anti-radical activities of representative antioxidants using different assays. The oxygen radical absorption capacity (ORAC) assay has two mechanistic stages. We classified antioxidant behavior using two characteristic values thought to be related to the two stages - peroxyl radical formation time (lag time) and fluorescein annihilation rate (k _obs) - by applying Voronoi polyhedral division. We focused on four class-representative antioxidants, Trolox ®, vitamin C, l-cysteine, and 2,6-di‑tert‑butyl‑p-cresol, and compared their characteristic activities with those of edaravone. Our analysis indicates that edaravone is in the same group as cysteine and may function via a similar mechanism. Our results suggest that analyzing lag time and k _obs is a useful method to characterize antioxidants.

Comparative assessment of functional properties, free and bound phenolic profile, antioxidant activity, and in vitro bioaccessibility of rye bran and its insoluble dietary fiber

In cereals, 95% of dietary fiber is associated with phenolic compounds. The present study examined the functional properties, phenolic composition, antioxidant activity, and in vitro bioaccessibility of phenolics and flavonoids present in rye bran (RB) and its insoluble dietary fiber (IDF). Compared to RB, higher functional properties (WHC, WRC, and OHC) were represented by IDF due to its porous structure. The IDF contained lower free but higher bound phenolics and flavonoids content as compared to RB, whereas highest total phenolics (556.6 mg GAE/100 g) and flavonoids (378.3 mg RE/100 g) content were observed in IDF. Results had identified significant differences (p < .05) in phenolic acids composition between RB and IDF determined by HPLC-MS and the total phenolic acids were higher in IDF. The antioxidant capacity of IDF was higher than RB in DPPH, FRAP, ABTS, and reducing power assay. However, the in vitro phenolics and flavonoids bioaccessibility of IDF was much lower because of its high content of bound phenolics and flavonoids. PRACTICAL APPLICATIONS: A successful comparative study between RB and its IDF has been conducted in this research work that edifies the health benefits associated with the phytochemicals linked with RB and IDF. The present study also carries rich information regarding the cereal chemistry of RB that truly facilitates the food developers to specifically focus on the bioaccessibility of phenolic compounds present in IDF and RB. The findings about the functional properties and antioxidant capacities of RB and its IDF can also open new research horizons when dealing with food product development tasks, specifically related to therapeutic and medically tailored meals for the targeted customers.

Development and Characterization of Citrus Junos Pomace Pectin Films Incorporated With Rambutan (Nephelium Lappaceum) Peel Extract

New packaging materials using biopolymers have been studied to substitute synthetic packaging materials that lead to environmental pollution. In this study, a new biodegradable packaging material was developed using the pectin extracted from Citrus junos pomace, which is considered a food processing byproduct. Rambutan peel extract (RPE), at different concentrations (0.25%, 0.5%, and 1.0%), was added as an active material, and the functional properties of the C. junos pectin (CJP) films were evaluated. The incorporation of RPE enhanced the extensibility of the CJP films and their light-blocking ability by decreasing light transmittance. As the concentration of RPE increased, antioxidant activities of the CJP films increased, along with an increase in total phenolic content. Subsequently, the CJP prepared in this study can be used as a low-cost active biodegradable film material, and RPE can be added as a natural antioxidant for the CJP films to confer antioxidant activity.

Effects of superfine grinding on asparagus pomace. Part I: Changes on physicochemical and functional properties

The effects of superfine grinding on the physicochemical and functional properties of asparagus pomace were investigated. The results showed that in terms of the specific surface area, water solubility, soluble dietary fiber content, and ratio of insoluble dietary fiber to soluble dietary fiber, finer samples usually possessed better physicochemical properties compared with coarse samples. However, grinding samples excessively to produce small particle sizes could reduce the water-holding capacity, oil-binding capacity, and swelling capacity. In addition, the extraction of both free and bound phenolics in asparagus pomace powder samples and the samples' absorption of both nitrite ion and glucose showed typical bell-shaped curves, demonstrating that superfine grinding could significantly impact the various properties of asparagus pomace. This study should provide insights into the effect of micronization on the functionalities of fiber-rich food materials. PRACTICAL APPLICATION: This article deals with the effects of superfine grinding on the physicochemical and functional properties of asparagus pomace. The results showed that the properties of asparagus pomace did not always improve gradually with decreasing particle size. With a decrease in granularity, some parameters showed a bell-shaped curve whereas others initially increased and then stabilized, indicating that in actual production, the crushing particle size should be determined according to actual needs or target parameters.

Effect of superfine grinding on the physicochemical properties of bulbs of Fritillaria unibracteata Hsiao et K.C. Hsia powder

This work aimed to determine the influence of superfine grinding on the physicochemical properties of bulbs of Fritillaria unibracteata Hsiao et K.C. Hsia (BFU) powder. For this purpose, fine powder (FP) and two superfine powders (SPs) were obtained via superfine and conventional grinding methods. The properties of different powders were studied and compared. Compared with FP, SPs exhibited higher values in terms of the angle of repose, swelling capacity, ethanol extraction yield, total alkaloid content, and imperialine content, while lower values in terms of particle size and bulk density. Especially, the total alkaloid content of SP-I increased by 66.7%. Proper grinding is more conducive to reduce particle size and improve alkaloid content. FTIR analysis indicates that no new functional groups produced after superfine grinding. XRD analysis suggests that grinding treatment lead to decreases in the crystallinity. Therefore, superfine grinding displays immense potential in the BFU application.

Analysis by UPLC-DAD-ESI-MS of Phenolic Compounds and HPLC-DAD-Based Determination of Carotenoids in Noni ( Morinda citrifolia L.) Bagasse

Noni bagasse is usually wasted after the noni juice extraction process. The purpose of this study was to investigate the phytochemical composition of noni bagasse (with and without seeds) obtained after a 1 week period of a short-term juice drip-extraction process from over-ripe noni fruit. Totals of free phenolics, flavonoids, condensed tannins, carotenoids, and most of the minerals were higher in bagasse without seeds (NSB) than in bagasse with seeds (WSB), whereas bound phenolics and total and insoluble dietary fiber were higher in WSB than in NSB. β-Carotene and lutein, quantified by HPLC-DAD, were higher in both bagasse than in juice. A total of 16 phenolic compounds and 2 iridoids were determined by UPLC-DAD-ESI-MS. Among them, procyanidin B-type dimer, caffeoylquinic-acid-hexoside, and quercetin-hexose-deoxyhexose have not been previously reported in noni bagasse, noni juice, or noni fruit. Isorhamnetin-3- O-rutinoside was the most abundant compound in both bagasses. In conclusion, both bagasses are potential sources of phytochemical compounds for the food and pharmaceutical industries.

Protective Effect of Water Extract of Citrus Pomace against AAPH-Induced Oxidative Stress In Vitro in Vero Cells and In Vivo in Zebrafish

Citrus pomace (CP) is a by-product occurred during juice or other products processing. The enormous amount of CP caused serious environmental issues. However, CP is rich in a variety of bioactive compounds. In the present study, a water extract of CP (CPW) was prepared from the by-product and the in vitro and in vivo antioxidant activities of CPW were investigated. The in vitro antioxidant activities of CPW were evaluated by measuring the free radical scavenging activity and protective effects against 2,2-azobis(2-amidinopropane) hydrochloride (AAPH)-induced oxidative stress in Vero cells. CPW scavenges 1,1-diphenyl-2-picrylhydrazyl, alkyl, and hydroxyl radicals at IC₅₀ of 0.16±0.00, 0.31±0.01, and 0.86±0.02 mg/mL, respectively. In addition, CPW improved cell viability and scavenged intracellular reactive oxygen species (ROS) in AAPH-stimulated Vero cells in a dose-dependent manner. The in vivo antioxidant activities of CPW were investigated in a model of AAPH-induced zebrafish embryos. CPW significantly improved the survival rates and reduced heartbeat rates in AAPH-stimulated zebrafish. Furthermore, the intracellular ROS and cell death levels were remarkably decreased in CPW-treated zebrafish. Therefore, the present results indicated that CPW possesses potent in vitro and in vivo antioxidant properties and could be a potential ingredient used in food, pharmaceutical, and cosmetic industries.

Valuable Compound Extraction, Anaerobic Digestion, and Composting: A Leading Biorefinery Approach for Agricultural Wastes

In a society where the environmental conscience is gaining attention, it is necessary to evaluate the potential valorization options for agricultural biomass to create a change in the perception of the waste agricultural biomass from waste to resource. In that sense, the biorefinery approach has been proposed as the roadway to increase profit of the agricultural sector and, at the same time, ensure environmental sustainability. The biorefinery approach integrates biomass conversion processes to produce fuels, power, and chemicals from biomass. The present review is focused on the extraction of value-added compounds, anaerobic digestion, and composting of agricultural waste as the biorefinery approach. This biorefinery approach is, nevertheless, seen as a less innovative configuration compared to other biorefinery configurations, such as bioethanol production or white biotechnology. However, any of these processes has been widely proposed as a single operation unit for agricultural waste valorization, and a thoughtful review on possible single or joint application has not been available in the literature up to now. The aim is to review the previous and current literature about the potential valorization of agricultural waste biomass, focusing on valuable compound extraction, anaerobic digestion, and composting of agricultural waste, whether they are not, partially, or fully integrated.

Enhancing cellulose functionalities by size reduction using media-mill

This study explored the feasibility of enhancing cellulose functionalities by using media milling to reduce the size of cellulose particles, and assayed various physicochemical and physiological properties of the resulting cellulose. Cellulose has been recognized as dietary fiber by USFDA due to its health benefits. However, its properties like low degradability, stiff texture, and insolubility in water limits its applicability in foods. Milling reduced the volume mean size of cellulose from 25.7 μm to 0.9 μm, which in turn increased the specific surface area (36.78-fold), and swelling capacity (9-fold). Conversely, a reduction in the bulk density (1.41 to 1.32 g/mL) and intrinsic viscosity (165.64 to 77.28 mL/g) were found. The milled cellulose also had significantly enhanced capacity for holding water and binding bile acids and sugars. Moreover, the size reduction also resulted in increased fermentability of cellulose into short chain fatty acids using three human fecal microflora samples. The increase in production of acetate (2880.60%), propionate (2738.52%), and butyrate (2865.89%) after fermentation of cellulose for 24 h were significantly enhanced by size reduction. With these improved characteristics, the milled cellulose might have beneficial physiological effects including laxation as well as reduced blood cholesterol and glucose attenuation.

A Comparison of the Chemical Composition, In Vitro Bioaccessibility and Antioxidant Activity of Phenolic Compounds from Rice Bran and Its Dietary Fibres

The composition, in vitro bioaccessibility and antioxidant activities of the phenolic compounds in defatted rice bran (DRB) and its soluble and insoluble dietary fibres were systematically evaluated in this study. The total phenolic content of insoluble dietary fibre from DRB (IDFDRB) was much higher than that of the soluble dietary fibre from DRB (SDFDRB) but was 10% lower than that of DRB. Bound phenolics accounted for more than 90% of the total phenolics in IDFDRB, whereas they accounted for 34.2% and 40.5% of the total phenolics in DRB and SDFDRB, respectively. Additionally, the phenolic profiles and antioxidant activities were significantly different in DRB, SDFDRB and IDFDRB. The phenolic compounds in IDFDRB were much less bioaccessibility than those in DRB and SDFDRB due to the higher proportion of bound phenolics in IDFDRB. Considering that bound phenolics could be released from food matrices by bacterial enzymes in the large intestine and go on to exert significant beneficial health effects in vivo, further studies on IDFDRB are needed to investigate the release of the phenolics from IDFDRB via gut microbiota and the related health benefits.

Antioxidant and antiplatelet activities of flavonoid-rich fractions of three citrus fruits from Korea

Three different fractional (methanol, ethyl acetate and hexane) extracts from yuzu (Citrus junos Sieb ex Tanaka), hallabong [(C. unshiu Marcov × C. sinensis Osbeck) × C. reticulata Blanco] and orange (C. sinensis) were evaluated for their antioxidant activity and antiplatelet effects. 2,2-Diphenyl-1-Picrylhydrazyl (DPPH), cupric reducing antioxidant capacity (CUPRAC) and ferric-reducing antioxidant power (FRAP) methods were used for the antioxidant activity tests. Total flavonoids and total phenolics were also evaluated spectrophotometrically. The ethyl acetate fraction contained the highest total flavonoid and total phenolic content and exhibited the highest antioxidant activities (185.2 ± 14.5 and 208.7 ± 17.5 mg/g dry extract for FRAP and CUPRAC values, respectively). The total phenolic and total flavonoid content ranged from 58.2 ± 1.4 to 102.4 ± 8.6 and 19.6 ± 0.5 to 64.3 ± 0.8 mg/g dry extract, respectively. The results of DPPH assay showed that ethyl acetate fractions had the least IC50 values (0.12 ± 0.002, 0.04 ± 0.0006, in mg/mL for orange and hallabong samples, respectively) followed by the hexane fraction (0.19 ± 0.007 mg/mL) of the orange sample. For all fractions, the antioxidant activity and contents of total phenolics and total flavonoids correlated well with each other. In vitro investigation of the antiplatelet effect showed that ethyl acetate fraction has the highest inhibition (84.3 ± 5.8 to 96.1 ± 1.8 %). Hexane and MeOH fractions of hallabong and orange samples inhibited platelet aggregations by less than or equal to 41 %.

Effect of micronization on the physicochemical properties of insoluble dietary fiber from citrus (Citrus junos Sieb. ex Tanaka) pomace

The aim of this work was to study the effect of micronization (mechanical and jet grindings) on the physicochemical properties of the insoluble dietary fiber from citrus pomace in comparison with ordinary grinding. The results showed that micronization treatment effectively pulverized the IDF-CP powders to micron scale and significantly increased the soluble dietary fiber content (p < 0.05). Compared with mechanical grinding, jet grinding was more effective in size reduction and resulted in IDF-CP powders with narrower particle size distributions. Micronized IDF-CP powders had smaller particle size, smoother surface, higher fluidity, cation-exchange capacity, and metal cation binding capacity values, but lower water holding capacity, oil holding capacity, and swelling capacity values. These functional properties were significantly dependent on surface area and particle size (D0.5). The present study suggested that micronization treatments could modify functional properties of IDF-CP powders, which promotes their use in food applications.