Feruloyl oligosaccharides stimulate the growth of Bifidobacterium bifidum

Hepatoprotective effects of almond shells against carbon tetrachloride induced liver injury in albino rats

Liver injury is a prevalent pathological process that can give rise to conditions such as fatty liver, cirrhosis, fibrosis, and even cancer. It has been observed that plants and natural products possess significant protective effects against liver injury. Current study was performed to investigate the efficacy of almonds shell against carbon tetrachloride (CCl4) induced hepatotoxicity in rat model. As almonds shell contain a large variety of phenolic and flavonoid compounds, which are largely associated with antioxidant and hepatoprotective properties. For this purpose, screening of small-scale library of twenty plant extracts was performed for evaluation of antioxidant potential by DPPH assay. The data revealed that almonds shell extract (ASEE) exhibited potent antioxidant activity. This potent extract was further evaluated for hepatoprotective activity in in vivo rat model on 30 rats, divided into 6 groups of 5 rats each. On 29th day all rats were sacrificed and blood serum was collected for further analysis. Liver tissues were also preserved in formalin for histopathology. The results demonstrated that ASEE displayed a protective effect on liver function tests (LFT), renal function tests (RFT), and lipid biomarkers in comparison to the CCl4 group. The histological data also unveiled a substantial safeguarding impact on liver damage, characterized by a reduction in apoptosis, diminished liver hemorrhage, and decreased accumulation of cellular debris. The data indicates that ethanolic extract from almond shells possesses hepatoprotective potential, suggesting its viability as an alternative source for hepatoprotective drug development after pre-clinical research.

Improving the Yield of Feruloyl Oligosaccharides from Rice Bran through Enzymatic Extrusion and Its Mechanism

Rice bran, rich in feruloyl arabinoxylan, is a good source of feruloyl oligosaccharides (FOs). To prepare FOs, bran was often hydrolyzed by amylase and protease to remove starch and protein and then hydrolyzed by xylanase, which was time-consuming and had a low yield. To solve the above problems, enzymatic extrusion was used to treat rice bran, and the effects of traditional hydrolysis, a combination of traditional extrusion and hydrolysis (extrusion-hydrolysis) and enzymatic extrusion on the yield of FOs were investigated and compared in this study. It was found that traditional extrusion and enzymatic extrusion significantly increased the yield of FOs. Particularly, the yield of FOs resulting from enzymatic extrusion was increased to 5.78%, while the yield from traditional hydrolysis was 4.23%. Microscopy analysis showed that extrusion damaged the cell wall of bran, which might increase the accessibility of xylanase to arabinoxylan and the yield of FOs. Spectroscopy analysis suggested that FOs obtained by different pretreatments had similar structures. It was obvious that enzymatic extrusion saved the time for removal of starch and protein and increased the yield of FOs. In addition, the highest yield of FOs was found at the moisture content of 30% and the screw speed of 50 rpm. This study provided an efficient method for the preparation of FOs that is suitable for industrial production.

Interaction between dietary fiber and bifidobacteria in promoting intestinal health

Bifidobacteria are considered as probiotics due to their role in promoting intestinal health, including regulating intestinal flora, controlling glycolipid metabolism, anti-colitis effects. Dietary fiber is considered as prebiotic favoring gut health. It also can be used as carbon source to support the growth and colonization of probiotics like bifidobacteria. However, because of genetic diversity, different bifidobacterial species differ in their ability to utilize dietary fiber. Meanwhile, dietary fiber with different structural properties has different effects on the bifidobacteria proliferation. The interaction between dietary fiber and bifidobacteria will consequently lead to a synergistic or antagonistic function in promoting intestinal health, therefore affecting the application of combined use of dietary fiber and bifidobacteria. In this case, we summarize the biological function of bifidobacteria, and their interaction with different dietary fiber in promoting gut health, and finally provide several strategies about their combined use.

Protective role of three differently processed corn bran on glucose and lipid concentrations in d-galactose-induced mice model

In this research, the effects of three differently processed corn bran (corn bran soluble hemicellulose (HEM), hemicellulose hydrolyzed by oxalic acid (HOA), Amberlite XAD-2 eluate (XE)) on the changes of glucose and lipid concentrations of d-galactose (d-gal)-induced mice were investigated. The mice were divided into five groups and intragastric administration HEM, HOA, and XE at 200 mg/kg Body Weight (BW) for continuously 6 weeks. Mice were submitted under oral glucose tolerance test (OGTT).Then, the serum insulin, glucagon-like peptide-1(GLP-1), serum C-peptide, hepatic glycogen (HG), muscle glycogen (MG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) of all the mice were detected. As we can see, by inducing with d-gal, the glucose and lipid concentrations of aging mice could be effectively regulated by HEM, HOA, and XE. High degree of esterification feruloylated oligosaccharides has the most obvious effect of regulating glucose and lipid concentrations. PRACTICAL APPLICATIONS: Corn bran has not been fully paid attention owing to the rough taste and the poor water solubility. Actually, corn bran, a renewable resource available in a large quantity, could be a goods source of valuable consumer products. The results of this study indicated that three differently processed corn brans could regulate glucose and lipid concentrations and XE had the most obvious effect of regulating glucose and lipid concentrations. Corn bran could advantage as a new type of environmentally and inexpensive food supplements on reducing blood glucose and lipid concentrations.

Effective bifidogenic growth factors cyclo-Val-Leu and cyclo-Val-Ile produced by Bacillus subtilis C-3102 in the human colonic microbiota model

Bifidobacterium species are known to fulfill important functions within the human colon. Thus, stimulating the activity of bifidobacteria is important to maintain host health. We revealed that culture supernatants of Bacillus subtilis C-3102 (referred to as C-3102) stimulated the growth of Bifidobacterium species. In this study, we isolated and identified six bifidogenic growth factors, which were cyclo (D-Val-D-Ile), cyclo (L-Val-D-Ile), cyclo (D-Val-L-Ile), cyclo (L-Val-L-Ile), cyclo (D-Val-L-Leu) and cyclo (L-Val-L-Leu). These six cyclic dipeptides increased the growth of Bifidobacterium species and had no effect on potentially harmful gut organisms. Moreover, supplementation with a mixture of these six cyclic dipeptides significantly increased the abundance of microorganisms related to the genus Bifidobacterium in a human colonic microbiota model culture system, although supplementation with a single type of dipeptide had no effect. These results show that cyclic dipeptides containing Val-Leu and Val-Ile produced by C-3102 could serve as bifidogenic growth factors in the gut microbial community.

Structural features, interaction with the gut microbiota and anti-tumor activity of oligosaccharides

Some oligosaccharides are regarded as biological constituents with benefits to human health in an indirect way. They enter the intestinal tract to be fermented by the gut microbiota, causing changes in the abundance and composition of the gut microbiota and producing fermentation products such as short-chain fatty acids (SCFAs). In this review, the structural features and biological activities of eight common natural oligosaccharides were summarized, including human milk oligosaccharides (HMOS), xylo-oligosaccharides (XOS), arabinoxylo-oligosaccharides (AXOS), isomaltooligosaccharides (IMOS), chitin oligosaccharides (NACOS), mannan-oligosaccharides (MOS), galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS). Furthermore, XOS were selected to explain the anti-tumor mechanism mediated by gut microbiota. The review aims to reveal primary structural features of natural functional oligosaccharides related to the biological activities and also provide an explanation of the anti-tumor activity of functional oligosaccharides mediated by the gut microbiota.

Some oligosaccharides are regarded as biological constituents with benefits to human health in an indirect way.

Effect of ferulic acid sugar ester with high molecular mass from corn bran on proliferation of intestinal bifidobacteria in aged mice induced by D-galactose: The role of HFASE in the intestine

Our experiment was to study the effect of high molecular mass ferulic acid sugar ester (HFASE) from corn bran on proliferation of intestinal bifidobacteria in aged mice induced by D-galactose. The number of bifidobacteria in the intestine of D-galactose-induced aging mice was lower than that of normal mice. After the intragastric administration of different doses of HFASE (100, 200, and 300 mg kg^-1  day^-1 body weight) in experimental groups, the number of bifidobacteria was also higher than the aging group. The proliferation rate of bifidobacteria in the intestine of the experimental groups was fast in the first 24 days of feeding and then tended to be gentle. The H-l experimental group (100 mg/kg body weight) had the most obvious effect of the proliferation of bifidobacteria. PRACTICAL APPLICATIONS: As the by-product of corn starch processing, corn bran was usually processed into animal feed and sold at a low price. The results of this study indicated that high molecular mass corn bran ferulic acid sugar ester had the effect of promoting the proliferation of bifidobacteria in aging mice, which provided ideas for the development and application of corn bran in the food industries. It could be added as a raw material for functional foods to common foods such as yogurt, baked bread, cereals, and porridge.

Contribution of gut microbiota to metabolism of dietary glycine betaine in mice and in vitro colonic fermentation

BACKGROUND

Accumulating evidence is supporting the protective effect of whole grains against several chronic diseases. Simultaneously, our knowledge is increasing on the impact of gut microbiota on our health and on how diet can modify the composition of our bacterial cohabitants. Herein, we studied C57BL/6 J mice fed with diets enriched with rye bran and wheat aleurone, conventional and germ-free C57BL/6NTac mice on a basal diet, and the colonic fermentation of rye bran in an in vitro model of the human gastrointestinal system. We performed 16S rRNA gene sequencing and metabolomics on the study samples to determine the effect of bran-enriched diets on the gut microbial composition and the potential contribution of microbiota to the metabolism of a novel group of betainized compounds.

RESULTS

The bran-enriched study diets elevated the levels of betainized compounds in the colon contents of C57BL/6 J mice. The composition of microbiota changed, and the bran-enriched diets induced an increase in the relative abundance of several bacterial taxa, including Akkermansia, Bifidobacterium, Coriobacteriaceae, Lactobacillus, Parasutterella, and Ruminococcus, many of which are associated with improved health status or the metabolism of plant-based molecules. The levels of betainized compounds in the gut tissues of germ-free mice were significantly lower compared to conventional mice. In the in vitro model of the human gut, the production of betainized compounds was observed throughout the incubation, while the levels of glycine betaine decreased. In cereal samples, only low levels or trace amounts of other betaines than glycine betaine were observed.

CONCLUSIONS

Our findings provide evidence that the bacterial taxa increased in relative abundance by the bran-based diet are also involved in the metabolism of glycine betaine into other betainized compounds, adding another potential compound group acting as a mediator of the synergistic metabolic effect of diet and colonic microbiota.

Microencapsulated feruloyl esterase-producing lactobacilli ameliorate lipid profile and glycaemia in high fat diet-induced obese mice

The effect of oral administration of spray-dried microcapsules of feruloyl esterase (FE) producing Lactobacillus fermentum CRL1446 (Lf) and Lactobacillus johnsonii CRL1231 (Lj) on high fat diet-induced obese mice was investigated to evaluate whether these strains could be used as a biotherapeutic for obesity. Swiss albino mice were divided into a normal diet fed group receiving empty microcapsules (control), a high fat diet plus empty microcapsules (HFD group), HFD plus microcapsules with Lf (HFD-Lf group) and HDF plus microcapsules with Lj (HFD-Lj group). Microcapsules containing Lf or Lj at a dose of ~10⁷ cells/day/mouse were given orally for 7 weeks. Body weight gain, adiposity index, plasma leptin, lipid profiles, glycaemia, insulinemia, oral glucose tolerance, intestinal FE, glutathione peroxidase and glutathione reductase (GR) activities were determined. Administration of lactobacilli (HFD-Lf and HFD-Lj groups) improved metabolic parameters (triglyceride, total cholesterol, low-density lipoprotein cholesterol levels) and cardiovascular risk indicators (37-46% decrease of atherogenic index), and reduced body weight gain (29-38%), adiposity index (42-62%), plasma leptin levels, liver weight and fat deposition in liver. Intestinal FE activities significantly increased in HFD-Lf (62%) and HFD-Lj group (48%), thus improving hepatic GR activity (42% increment) compared to HFD group. Moreover, L. johnsonii increased HDL-cholesterol and L. fermentum reduced blood glucose to levels similar to the control. These FE-producing lactobacilli have the potential to improve biomarkers involved in obesity by increasing intestinal FE activity.

Processing and Prebiotics Characteristics of β-Glucan Extract from Highland Barley

β-glucan extract (GE) was obtained from highland barley bran using alkaline–acid–alcohol extraction method. The stability, solubility, foaming ability, and prebiotics characteristics of GE were assessed consecutively. GE demonstrated excellent heat stability (hardly degraded at 220 °C) and pH stability, especially at neutral or alkaline condition, and its solubility was significantly influenced by temperature instead of pH or NaCl, achieving 0.91 g/100 g at 100 °C. Good foaming ability and foam stability of GE were observed during low temperatures (≤40 °C), neutral or alkaline condition. GE indicated a strong anti-digestibility capacity of resisting the hydrolysis of α-amylase and simulated human gastric acid. Interestingly, GE could effectively promote the growth of Lactobacillus bulgaricus and Bifidobacterium adolescentis, which was close to fructooligosaccharide. The results of this study could offer valuable information for the application of β-glucan from highland barley as prebiotics in promoting human intestinal health metabolism.

Lactobacillus fermentum CRL1446 Ameliorates Oxidative and Metabolic Parameters by Increasing Intestinal Feruloyl Esterase Activity and Modulating Microbiota in Caloric-Restricted Mice

The purpose of this study was to determine whether the administration of the feruloyl esterase (FE)-producing strain Lactobacillus fermentum CRL1446 enhances metabolic and oxidative parameters in caloric-restricted (CR) mice. Balb/c male mice were divided into ad libitum fed Group (ALF Group), CR diet Group (CR Group) and CR diet plus L. fermentum Group (CR-Lf Group). CR diet was administered during 45 days and CRL1446 strain was given in the dose of 10⁸ cells/mL/day/mouse. FE activity was determined in intestinal mucosa and content at Day 1, 20 and 45. Triglyceride, total cholesterol, glucose, thiobarbituric acid reactive substances (TBARS) levels and glutathione reductase activity were determined in plasma. Gut microbiota was evaluated by high-throughput sequencing of 16S rRNA gene amplicons. At Day 45, total intestinal FE activity in CR-Lf Group was higher (p = 0.020) than in CR and ALF groups and an improvement in both metabolic (reductions in triglyceride (p = 0.0025), total cholesterol (p = 0.005) and glucose (p < 0.0001) levels) and oxidative (decrease of TBARS levels and increase of plasmatic glutathione reductase activity (p = 0.006)) parameters was observed, compared to ALF Group. CR diet increased abundance of Bacteroidetes and CRL1446 administration increased abundance of Bifidobacterium and Lactobacillus genus. L. fermentun CRL1446 exerted a bifidogenic effect under CR conditions.

Isolation and identification of feruloylated arabinoxylan mono- and oligosaccharides from undigested and digested maize and wheat

Feruloylated arabinoxylan mono- and oligosaccharides (F-AXOS) are a subject of interest because of their prebiotic and antioxidant properties. We aimed at isolating and identifying F-AXOS from maize, wheat, wheat bran and wheat aleurone using HPLC and LC-MS/MS. Prior to extraction of F-AXOS, samples were subjected to either simulated gastric fluid with enzymes (gastric) or without enzymes (pH) or water (aqueous) at 37 °C. F-AXOS present in all samples were identified as 5-O-feruloyl-α-L- arabinofuranose and possibly 5-O-feruloyl-α-L-arabinofuranosyl-(1 → 3)-O-β-D-xylopyranose. Their mean content, measured as esterified ferulic acid (FA), was 2.5 times higher in maize (10.33 ± 2.40 μg/g) compared to wheat. Digestion under gastric or pH conditions resulted in a two-fold increase in F-AXOS in all samples. The level of F-AXOS produced during gastric or pH condition was positively correlated to the insoluble bound FA content of the sample (R(2) = 0.98). 5-O-Feruloyl-α-L- arabinofuranose was the only identifiable F-AXOS released during gastric digestion. Our results suggest feruloyl arabinose is the most abundant form of F-AXOS in maize and wheat.

Adjuvant properties of water extractable arabinoxylans with different structural features from wheat flour against model antigen ovalbumin

Despite the numerous benefits of AX on the immune system and gut bacteria, the potential adjuvant activity of WEAX on immune responses has not been adequately investigated.

Direct production of feruloyl oligosaccharides and hemicellulase inducement and distribution in a newly isolated Aureobasidium pullulans strain

Studies were carried out to screen and identify strains that are able to directly produce ferulic oligosaccharides (FOs) from wheat bran (WB). The inducement and distribution of hemicellulases from strain 2012, which was identified as a non-melanin secreting strain of Aureobasidium pullulans (A. pullulans), were also determined. In a 60 g/L WB solution, A. pullulans could produce 545 nmol/L FOs, 64.12 IU/mL xylanase and 0.14 IU/mL ferulic acid esterase (FAE). A. pullulans was cultivated in media with WB, glucose, xylose, sucrose, lactose or xylan as the carbon source, and hemicellulases were mainly induced by xylan and WB and inhibited by glucose and sucrose. Xylanase and FAE were mainly present in the culture filtrate, xylosidase in the hyphal filaments and arabinofuranosidase was a membrane-bound enzyme. The yield of FOs was positively correlated to the hemicellulases activity, and significantly positively (P < 0.05) correlated to the xylanase activity (r = 0.992).

Feruloyl-L-arabinose attenuates migration, invasion and production of reactive oxygen species in H1299 lung cancer cells

Ferulic acid (FA), a phenolic compound, is an abundant dietary antioxidant and exerts the mitogenic effect on cells. Recently, we isolated an active FA derivative, namely feruloyl-L-arabinose (FAA), from coba husk. The aim of this study was to investigate the effects of FAA on the proliferation, migration and invasion of H1299 human lung cancer cells. Our results showed a strong antioxidant potential of FAA. Additionally, FAA inhibited the migration and invasion ability, while causing a significant accumulation of G2/M-population, of H1299 tumor cells in a dose-dependent manner, whereas no significant change on cell proliferation was observed. Results from the wound healing assay revealed that cell migration ability was markedly inhibited by FAA treatments. Similarly, results of gelatin zymography study showed that FAA treatments significantly decreased the activities of matrix metalloproteinase (MMP)-2 and MMP-9, suggesting that FAA-mediated inhibition on migration and invasion of lung cancer cells may be achieved by the down-regulation of the MMPs activities. Taken together, our present work provides a new insight into the novel inhibitory function of FAA on cell migration in H1299 cells, suggesting its promising role in the chemoprevention of lung cancer.

In vitro antioxidant activity of feruloyl arabinose isolated from maize bran by acid hydrolysis

In this study feruloylated oligosaccharides (FOs) was released from maize bran by hydrochloric acid hydrolysis, and feruloyl arabinose (F-Ara) was obtained by D301 macroporous resin chromatography followed by polyamide resin purification from FOs. After structural identification, the antioxidant activity of F-Ara was evaluated in vitro by DPPH and superoxide radical scavenging activity assay, reducing power assay and chelating activity assay. The results show that F-Ara exhibited antioxidant activity in vitro when compared to standard antioxidants such as butylated hydroxyanisole, ferulic acid and L-ascorbic acid. The antioxidant activity depends on the concentration and increases with increasing dose of sample. The present study suggests that F-Ara possesses promising future for its strong reducing power, chelating activity and free radical-scavenging activity. Therefore, it can be a natural and efficient antioxidant used in food, medicine and cosmetic.

Influence of dietary ingredients on in vitro inflammatory response of intestinal porcine epithelial cells challenged by an enterotoxigenic Escherichia coli (K88)

Enterotoxigenic Escherichia coli (ETEC) K88 is the main bacterial cause of diarrhea in piglets around weaning and the adhesion of ETEC to the intestinal mucosa is a prerequisite step for its colonization. In this study, the adhesion of a fimbriated ETEC and a non-fimbriated E. coli (NFEC) to the intestinal cells and the activation of the innate immune system were evaluated using a porcine intestinal epithelial cell line (IPEC-J2). The impact of several feedstuffs (wheat bran (WB); casein glycomacropeptide (CGMP); mannan-oligosaccharides (MOS); locust bean extract (LB) and Aspergillus oryzae fermentation extract (AO)) on ETEC attachment and the inflammatory response were also studied. The gene expression of TLR-4; TLR-5; IL-1β; IL-8; IL-10 and TNF-α were quantified using Cyclophilin-A, as a reference gene, and related to a non-challenged treatment. The fimbriated strain was markedly better than the non-fimbriated strain at adherence to intestinal cells and inducing an inflammatory response. All the feedstuffs studied were able to reduce the adhesion of ETEC, with the greatest decrease with CGMP or MOS at highest concentration. Regarding the inflammatory response, the highest dose of WB promoted the lowest relative expression of cytokines and chemokines. All tested feedstuffs were able to reduce the adhesion of ETEC to IPEC-J2 and interfere on the innate inflammatory response; however WB should be further studied according to the beneficial results on the intestinal inflammatory process evidenced in this study.

Feruloylated and nonferuloylated arabino-oligosaccharides from sugar beet pectin selectively stimulate the growth of Bifidobacterium spp. in human fecal in vitro fermentations

The side chains of the rhamnogalacturonan I fraction in sugar beet pectin are particularly rich in arabinan moieties, which may be substituted with feruloyl groups. In this work the arabinan-rich fraction resulting from sugar beet pulp based pectin production was separated by Amberlite XAD hydrophobic interaction and membrane separation into four fractions based on feruloyl substitution and arabino-oligosaccharide chain length: short-chain (DP 2-10) and long-chain (DP 7-14) feruloylated and nonferuloylated arabino-oligosaccharides, respectively. HPAEC, SEC, and MALDI-TOF/TOF analyses of the fractions confirmed the presence of singly and doubly substituted feruloylated arabino-oligosaccharides in the feruloyl-substituted fractions. In vitro microbial fermentation by human fecal samples (n = 6 healthy human volunteers) showed a selective stimulation of bifidobacteria by both the feruloylated and the nonferuloylated long-chain arabino-oligosaccharides to the same extent as the prebiotic fructo-oligosaccharides control. None of the fractions stimulated the growth of the potential pathogen Clostridium difficile in monocultures. This work provides a first report on the separation of potentially bioactive feruloylated arabino-oligosaccharides from sugar beet pulp and an initial indication of the potentially larger bifidogenic effect of relatively long-chain arabino-oligosaccharides as opposed to short-chain arabino-oligosaccharides.

Influence of casein hydrolysates on the growth and lactic acid production of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus

The growth performance of Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus) was determined in the presence of casein hydrolysates produced by the action of five proteolytic enzymes (Alcalase, Flavorzyme, Neutrase, Papain and Trypsin) with various degrees of hydrolysis (DH). In addition, these five kinds of casein hydrolysates were fractionated by ultrafiltration and the influence of the amino acid composition of the peptides on the growth and lactic acid yield of yoghurt lactic acid bacteria (LAB) was studied. The results showed that the ultrafiltered fraction (<3000 Da) was the determinant stimulator in crude hydrolysates. Furthermore, the hydrophilic amino acid residua including His, Lys, Glu and Ser were beneficial for bacterial growth. Compared with control, the cell growth and lactic acid yield of yoghurt LAB were increased with the supplementation of the peptides fraction (<3000 Da) produced with papain by 65.1% and 49.6%, respectively.

Xylo-oligosaccharides and the gut micro-ecosystem

The human gastrointestinal microbiota is a complex micro-ecosystem. It influences a variety of intestinal functions and plays a key role in nutrition regulation, in maintaining the integrity of the epithelial barrier, and in the development of mucosal immunity. In the normal gut the population structure of the microbiota is relatively stable and the relationship between the microbiota and the host is mutually beneficial. The complex network of host-microbe interactions is thought to prohibit colonization by intruding pathogens and any disruption of the net may lead to the loss of the microecological balance which will bring about the relevant diseases. Xylo-oligosaccharides (XOS), an emerging food additive, cause prebiotic effects when ingested as part of the diet through the modulation of colonic microflora. XOS affect the gut health and remedy diseases related to intestinal microbe dysbiosis by promoting the growth of good bacteria and diminishing the growth of deleterious microorganisms.

Utilisation of corn (Zea mays) bran and corn fiber in the production of food components

The milling of corn for the production of food constituents results in a number of low-value co-products. Two of the major co-products produced by this operation are corn bran and corn fiber, which currently have low commercial value. This review focuses on current and prospective research surrounding the utilization of corn fiber and corn bran in the production of potentially higher-value food components. Corn bran and corn fiber contain potentially useful components that may be harvested through physical, chemical or enzymatic means for the production of food ingredients or additives, including corn fiber oil, corn fiber gum, cellulosic fiber gels, xylo-oligosaccharides and ferulic acid. Components of corn bran and corn fiber may also be converted to food chemicals such as vanillin and xylitol. Commercialization of processes for the isolation or production of food products from corn bran or corn fiber has been met with numerous technical challenges, therefore further research that improves the production of these components from corn bran or corn fiber is needed.

Effect of prebiotic xylooligosaccharides on growth performances and digestive enzyme activities of allogynogenetic crucian carp (Carassius auratus gibelio)

The effect of prebiotic xylooligosaccharides (XOS) on the growth performance and digestive enzyme activities of the allogynogenetic crucian carp, Carassius auratus gibelio, was investigated. XOS was added to fish basal semi-purified diets at three concentrations by dry feed weight: diet 1, 50 mg kg(-1); diet 2, 100 mg kg(-1); diet 3, 200 mg kg(-1), respectively. Twelve aquaria (n = 20) with three replicates for each treatment group (diets 1-3) and control treated without XOS were used. Weights of all collected carp from each aquarium were determined at the initial phase and at the end of the experiment, and the carp survival was also determined by counting the individuals in each aquarium. After 45 days, there were significant differences (P < 0.05) in the relative gain rate (RGR), and daily weight gain (DWG) of diets 1-3 were compared with the control. However, the survival rate was not affected (P > 0.05) by the dietary treatments. For enzymatic analysis, dissection produced a crude mixture of intestine and hepatopancreas of each segment to measure. The protease activity in the intestine and hepatopancreas content of fish in diet 2 (487.37 +/- 20.58 U g(-1) and 20.52 +/- 1.93 U g(-1)) were significantly different (P < 0.05) from that in the control (428.13 +/- 23.26 U g(-1) and 12.81 +/- 1.52 U g(-1)) and diet 3 (428.00 +/- 23.78 U g(-1) and 14.04 +/- 1.59 U g(-1)). Amylase activity in the intestine was significantly higher for diet 2 compared to diet 1 and the control. As for amylase in the hepatopancreas, assays showed higher activity in diet 2 (P < 0.05) compared to the rest.

Potential prebiotic activity of oligosaccharides obtained by enzymatic conversion of durum wheat insoluble dietary fibre into soluble dietary fibre

BACKGROUND AND AIMS

Epidemiological evidence indicates that cereal dietary fibre (DF) may have several cardiovascular health benefits. The underlying mechanisms have not yet been elucidated. Here, the potential nutritional effects of physico-chemical properties modifications of durum wheat dietary fibre (DWF) induced by enzyme treatment have been investigated.

METHODS AND RESULTS

The conversion of the highly polymerised insoluble dietary fibre into soluble feruloyl oligosaccharides of DWF was achieved by a tailored enzymatic treatment. The in vitro fermentation and release of ferulic acid by intestinal microbiota from DWF before and after the enzymatic treatment were assessed using a gut model validated to mimic the human colonic microbial environment. Results demonstrated that, compared to DWF, the enzyme-treated DWF (ET-DWF) stimulated the growth of bifidobacteria and lactobacilli. Concurrently, the release of free ferulic acid by ET-DWF was almost three times higher respect to the control. No effect on the formation of short chain fatty acids was observed.

CONCLUSIONS

The conversion of insoluble dietary fibre from cereals into soluble dietary fibre generated a gut microbial fermentation that supported bifidobacteria and lactobacilli. The concurrent increase in free ferulic acid from the enzyme-treated DWF might result in a higher plasma ferulic acid concentration which could be one of the reasons for the health benefits reported for dietary fibre in cardiovascular diseases.

Enzymatic solubilization of brewers' spent grain by combined action of carbohydrases and peptidases

Brewers' spent grain (BSG), a high-volume coproduct from the brewing industry, primarily contains proteins, barley cell wall carbohydrates, and lignin. To create new possibilities for the exploitation of this large biomass stream, the solubilization of BSG by the combined action of carbohydrases (Depol 740 and Econase) and peptidase (Alcalase and Promod 439) was explored. Hydrolysis protocols were optimized with respect to temperature (influencing both microbial contamination and rate of enzymatic hydrolysis), pH, enzyme dose, order of enzyme addition, and processing time. On the basis of this approach, one- and two-step protocols are proposed taking 4-8 h and yielding combined or separate fractions of hydrolyzed oligosaccharides and liberated hydrolyzed protein. Optimized procedures resulted in the solubilization of >80% of the proteinaceous material, up to 39% of the total carbohydrates, and up to 42% of total dry matter in BSG. Of the original xylan present in BSG, 36% could be solubilized. Sequential and simultaneous treatments with the two enzyme types gave similar results. In sequential processes, the order of the carbohydrase and peptidase treatments had only minor effects on the outcome. Depol 740 released more pentoses than Econase and gave slightly higher overall dry matter solubilization yields.

Protection of wheat bran feruloyl oligosaccharides against free radical-induced oxidative damage in normal human erythrocytes

The present work assessed the protective effect of water-soluble feruloyl oligosaccharides (FSH), ferulic acid ester of oligosaccharides from wheat bran, against in vitro oxidative damage of normal human erythrocytes induced by a water-soluble free radical initiator, 2,2'-azobis-2-amidinopropane dihydrochloride (AAPH). In the whole process of AAPH-initiated oxidation, hemolysis occurred quickly after the lag time. The rate of hemolysis is correlated dose-dependently with AAPH concentration. Significant decrease in reduced glutathione (GSH) levels of erythrocyte with concomitant enhancement in oxidized gluthione (GSSG) levels was noticed. It was also observed that lipid and protein peroxidation of erythrocytes induced by AAPH was significantly increased, and scanning electron microscopy observations showed that AAPH induced obvious morphological alteration in the erythrocytes from a smooth discoid to an echinocytic form. FSH suppressed depletion of GSH, lipid peroxidation, and methaemoglobin and protein carbonyl group formation of erythrocytes in concentration- and time-dependent manners, remarkably delayed AAPH-induced hemolysis. Morphological changes to erythrocyte caused by AAPH were effectively protected by FSH. It was also observed that FSH could work synergistically with endogenous antioxidants in erythrocytes. These results indicated that FSH efficiently protected normal human erythrocytes against oxidative stress, and they could be used as a potential source of natural antioxidants.

Distribution of bound hydroxycinnamic acids and their glycosyl esters in barley (Hordeum vulgare L.) air-classified flour: comparative study between reversed phase-high performance chromatography-mass spectrometry (RP-HPLC/MS) and spectrophotometric analysis

The level of bound hydroxycinnamic acid was determined by spectrophotometry (as total hydroxycinnamic compounds and free-radical-scavenging activity) and reversed-phase high-performance chromatography (RP-HPLC) coupled to mass spectrometry (MS) in barley flours (whole meals and air-classified fractions: coarse fraction and fine fraction). Hydroxycinnamic acids and their derivatives were the main bound phenols in barley flours. A total of 12 different hydroxycinnamic acids were identified and quantified by HPLC/diode array detector (DAD)-MS within 90 min. Ferulic acid (as a simple and glycosylated derivative) was the main phenolic acid in barley flours, representing 89-93% of total hydroxycinnamic acids. The amount of total hydroxycinnamic acid in air-classified coarse fraction was 2 and 3 times higher than those of whole meal and the air-classified fine fraction, respectively. Similarly, the coarse fraction showed higher antioxidant activity (650.03 micromol of TEAC/100 g of flour) compared to whole meal and the fine fraction (388.78 and 320.27 micromol of TEAC/100 g of flour, respectively).

Enzymatic solubilization of proteins in brewer's spent grain

Brewer's spent grain (BSG) is an abundant, protein-rich coproduct from the beer industry. There is a growing interest in increasing and diversifying the exploitation of BSG and related coproducts for economic and environmental reasons. In this paper, we report on a study of the solubilization of proteinaceous material from BSG using several commercial peptidase preparations. Our data show that Alcalase is the most effective peptidase for solubilization of BSG proteins, with an ability to release up to 77% of total protein. The peptides produced by Alcalase had lower average molecular weight than peptides produced by the less effective enzymes. Processes that combined peptidase treatment with carbohydrate-degrading enzyme preparations such as Depol740 increased the solubilization of dry matter (from 30 to 43% under optimal conditions). However, such additional treatment had little effect on the solubilization of protein. The choice of enzyme dosage depends on the desired hydrolysis time and was assessed through several experiments. Protein solubilization was consistently better at pH 8.0 as compared to pH 6.8. Maximum protein solubilization at pH 8.0 within 4 h required the use of 10-20 microL Alcalase per g of dry matter. However, a considerable degree of solubilization (64%) and hydrolysates with high protein content could be obtained using doses down to only 1.2 microL. Amino acid composition analyses showed that Alcalase treatment solubilizes proline and glutamine (constituents of barley hordein) slightly more efficiently than the other amino acids in BSG.

In vitro three-stage continuous fermentation of wheat arabinoxylan fractions and induction of hydrolase activity by the gut microflora

In vitro fermentations were carried out by using a model of the human colon to stimulate microbial activities of gut bacteria. The model consisted of a three-stage culture system. Bacterial populations were evaluated under the effect of three types of arabinoxylan, a nonstarch polysaccharide derived from wheat, the water-unextractable arabinoxylan fraction (WU-AX), WU-AX pretreated with exogenous xylanase and the soluble water-extractable arabinoxylan fraction (WE-AX). The xylanase pretreated (WU-AX) had a stimulatory effect upon colonic bifidobacteria throughout all three vessels. Counts of Bacteroides spp. and Clostridium spp. were also both significantly reduced. Addition of the WU-AX substrates to the first vessel resulted in induction of bacterial synthesis of extracellular hydrolytic enzymes xylanase and ferulic acid esterase which are both required for bacterial metabolism of WU-AX; this induction was significantly greater with the xylanase treated WU-AX.

Structural characterisation by ESI-MS of feruloylated arabino-oligosaccharides synthesised by chemoenzymatic esterification

The chemoenzymatic synthesis of feruloylated arabino-oligosaccharides has been achieved, using a feruloyl esterase type C from Sporotrichum thermophile (StFaeC). The structure of the feruloylated products was confirmed by ESI-MS(n).