Chemical Composition, Functional and Antioxidant Properties of Dietary Fibre Extracted from Lemon Peel after Enzymatic Treatment.

Lemon peel represents an interesting by-product owing to its content of dietary fibre (DF) and (poly)phenols, which is of great importance for its valorisation. Hence, the objective of this study was to characterise the DF, total phenolic content (TPC), and antioxidant capacity of two lemon-peel-derived ingredients using two different methods (drying with warm air and enzymatic hydrolysis with pectinesterase). The analysis included a DF assessment, followed by neutral sugars characterisation through GC-FID and uronic acids determination via colorimetry. Subsequently, TPC and antioxidant capacity using the FRAP method were quantified through spectrophotometry. The swelling capacity (SWC), water retention capacity (WRC), and fat absorption capacity (FAC) were also determined as functional properties. It was observed that pectinesterase treatment led to a reduction in soluble DF and an increase in insoluble DF. This treatment also affected the pectin structure, thereby diminishing its ability to absorb water and fat within its matrix. The TPC was also reduced, resulting in a decrease in antioxidant capacity. Conversely, employing warm air exhibited a noteworthy increase in antioxidant capacity. This underscores its crucial contribution to the valorisation of lemon peel, not only by diminishing the environmental impact but also by enabling the acquisition of fibre ingredients with a noteworthy antioxidant capacity.

Interactive effects of dietary fibre and lipid types modulate gastrointestinal flows and apparent digestibility of fatty acids in growing pigs.

A total of eight ileal and caecal cannulated Yorkshire barrows were used to determine the interactions of dietary fibre (DF) and lipid types on apparent digestibility of DM and fatty acids (FA) and FA flows in gastrointestinal segments. Pigs were offered four diets that contained either pectin or cellulose with or without beef tallow or maize oil in two Youden square designs (n 6). Each period lasted 15 d. Faeces, ileal and caecal contents were collected to determine apparent ileal digestibility (AID), apparent caecal digestibility and apparent total tract digestibility (ATTD) of dietary components. The interactions between DF and lipid types influenced (P <0·05) the digestibility of DM and FA flows. The addition of maize oil decreased (P <0·05) AID of DM in pectin diets, and the addition of beef tallow depressed (P <0·001) ATTD of DM in cellulose diets. Dietary supplementation with beef tallow decreased (P <0·05) the AID of FA in pectin-containing diets but had no effects in cellulose-containing diets. Dietary supplementation with beef tallow increased (P <0·05) AID of SFA and PUFA and the flow of ileal oleic, vaccenic, linolenic and eicosadienoic acids and reduced the flow of faecal lauric, docosatetraenoic and docosapentaenoic acids in pectin- and cellulose-containing diets. In conclusion, the interaction between DF type and lipid saturation modulates digestibility of DM and lipids and FA flows but differs for soluble and insoluble fibre sources, SFA and unsaturated fatty acids and varies in different gastrointestinal segments.

Delivery of alpha-tocopherol through soluble dietary fibre-based nanofibres for improving the life span of Caenorhabditis elegans.

The effect of alpha-tocopherol (α-TOC) delivered by soluble dietary fibre-based nanofibres (α-TOC-SDNF) on the life span of nematode Caenorhabditis elegans N2 (wild type) and TK22 (mev-1 mutants) with and without heat shock was investigated. Without heat shock, the wild-type and mev-1 mutants maintained in the 100 µg/mL of α-TOC-SDNF had longer life spans than their respective blank control groups. With heat shock, the wild-type N2 in the 200 µg/mL of α-TOC-SDNF had a survival rate of 5% at day 49, while no nematodes survived in the blank control group. An increased pharyngeal pumping rate was observed in the α-TOC-SDNF treated mev-1 mutants worms compared to the blank control group. Encapsulating α-TOC in SDNF yielded protective effects and the life span and pumping rate of C. elegans was increased with α-TOC delivered by SDNF.

Beneficial effects of consumption of acerola, cashew or guava processing by-products on intestinal health and lipid metabolism in dyslipidaemic female Wistar rats.

This study assessed the effects of diet supplementation with industrial processing by-products of acerola (Malpighia emarginata D.C.), cashew (Anacardium occidentale L.) and guava (Psidium guajava L.) fruit on the intestinal health and lipid metabolism of female Wistar rats with diet-induced dyslipidaemia. Female rats were randomly divided into five groups: healthy control, dyslipidaemic control and dyslipidaemic experimental receiving acerola, cashew or guava processing by-products. Fruit processing by-products were administered (400 mg/kg body weight) via orogastric administration for 28 consecutive days. Acerola, cashew and guava by-products caused body weight reduction (3·42, 3·08 and 5·20 %, respectively) in dyslipidaemic female rats. Dyslipidaemic female rats receiving fruit by-products, especially from acerola, presented decreased faecal pH, visceral fat, liver fat and serum lipid levels, as well as increased faecal moisture, faecal fat excretion, faecal Bifidobacterium spp. and Lactobacillus spp. counts and amounts of organic acids in faeces. Administration of the tested fruit processing by-products protected colon and liver from tissue damage (e.g. destruction of liver and colon cells and increased fat deposition in hepatocytes) induced by dyslipidaemic diet. Dietary fibres and phenolic compounds in tested fruit by-products may be associated with these positive effects. The industrial fruit processing by-products studied, mainly from acerola, exert functional properties that could enable their use to protect the harmful effects on intestinal health and lipid metabolism caused by dyslipidaemic diet.

Characterization of fructans and dietary fibre profiles in raw and steamed vegetables.

Dietary fibre (DF) has many positive effects on human health associated with its functionality in the gastrointestinal tract. These benefits vary according to the type of DF. Vegetables can be a natural source of DF in the diet. However, to provide adequate nutritional advice, the content and profile of their various DF types must be characterised. This study aimed to determine the DF profile of 29 vegetables cultivated in Wallonia (Belgium) and the impact of steaming on these profiles. Using a combination of enzymatic, gravimetric and chromatographic methods, fructans, total dietary fibre (TDF), low- and high-molecular-weight soluble dietary fibre (SDF), and insoluble dietary fibre (IDF) were analysed. Results show that the DF content varies considerably among the 29 investigated vegetable varieties and species, but the influence of steaming is limited to a shift from IDF to high-molecular-weight SDF for 18 of the 29 tested vegetables, while fructans are preserved with not actual reduction in the DP.

Addition of arabinoxylan and mixed linkage glucans in porcine diets affects the large intestinal bacterial populations.

PURPOSE: To investigate the effects of two cereal soluble dietary fibres (SDF), wheat arabinoxylan (AX) and oat-mixed linkage glucans (MLG), on fermentative end-products and bacterial community profiles of the porcine caecum (Cae) and distal colon (DC). We hypothesised that feeding pigs these SDF would stimulate Cae and DC carbohydrate fermentation, resulting in a modification of the resident bacterial communities. METHODS: Five groups of six pigs were each fed one diet based on wheat starch (WS) only, or treatment diets in which some WS was replaced by 10 % AX, or 10 % MLG, a combination of 5 % AX:5 % MLG (AXMLG), or completely replaced with ground whole wheat. Post-euthanasia, Cae and DC digesta were collected for analysis of fermentative end-products, and bacterial community profiles were determined by 16S rRNA gene amplicon 454 pyrosequencing. RESULTS: Across all the SDF-containing diets, predominantly in the proximal region of the large intestine, Prevotella, Lactobacillus, Mitsuokella and Streptococcus were most significantly influenced (P < 0.05), while notable changes were observed for the Ruminococcaceae and Lachnospiraceae families in the Cae and DC. The addition of MLG or AXMLG had the greatest effect of influencing bacterial profiles, reducing sequence proportions assigned to the genus Clostridium, considered detrimental to gut health, with associated increases in short-chain fatty acid and reduced ammonia concentrations. CONCLUSIONS: This study demonstrated how the cereal SDF AX and MLG altered the large intestinal bacterial community composition, particularly proximally, further giving insights into how diets rich in specific complex carbohydrates shift the bacterial population, by increasing abundance and promoting greater diversity of those bacteria considered beneficial to gut health.

In vitro fermentability and prebiotic potential of soyabean Okara by human faecal microbiota.

At present, there is a huge interest in finding new prebiotics from agrofood industrial waste, such as the soyabean by-product Okara, rich in insoluble dietary fibre. A previous treatment of Okara with high hydrostatic pressure assisted by the food-grade enzyme Ultraflo ® L achieved a 58·2 % increment in its soluble dietary fibre (SDF) contents. Therefore, potential prebiotic effect of both treated and native Okara was assayed using 48 h, pH-controlled, anaerobic batch cultures inoculated with human faecal slurries, which simulate the human gut. Changes in faecal microbiota were evaluated using 16S rRNA-based fluorescence in situ hybridisation, whereas release of SCFA and lactic acid was assessed by HPLC. Both Okara samples exhibited potential prebiotic effects but Okara treated to maximise its SDF content showed higher SCFA plus lactic acid, better growth promotion of beneficial bacteria, including bifidobacteria after 4 and 48 h and lactobacilli after 4 h of fermentation, and a greater inhibition of potentially harmful bacterial groups such as clostridia and Bacteroides. Differences found between fructo-oligosaccharides and Okara substrates could be attributed to the great complexity of Okara's cell wall, which would need longer times to be fermented than other easily digested molecules, thus allowing an extended potential prebiotic effect. These results support an in vitro potential prebiotic effect of Okara.

Digestion-resistant maltodextrin effects on colonic transit time and stool weight: a randomized controlled clinical study.

PURPOSE: Increased awareness of the importance of dietary fibre has led to increased interest in "functional" fibre components like digestion-resistant maltodextrin (RMD). This randomized, placebo-controlled, double-blind study assessed the effects of RMD in the colonic transit time (CTT) and defecation characteristics (frequency, stool volume and consistency). METHODS: Sixty-six healthy adult volunteers (32 men) who did not have a daily defecation habit had a 7-day run-in period before the 21-day intervention period with RMD or placebo. CTT and segmental CTT (SCTT) were assessed by a single abdominal X-ray film taken at the end of both periods after radiopaque marker ingestion. Defecation characteristics and intestinal functions were also assessed, which were self-reported by patients. Intragroup comparisons were evaluated by Student's paired t test, Bonferroni test and Chi-square test, while time comparisons by analysis of variance (ANOVA) and time-by-treatment interaction by repeated-measures ANOVA. RESULTS: Fifty-seven subjects were assessed for CTT (placebo, n = 28; RMD, n = 29). In the RMD group, the total CTT, left SCTT and rectosigmoidal SCTT decreased significantly compared to baseline (p < 0.01 each; -13.3, -4.7, -8.7 h, respectively). Significant differences between groups were observed in total CTT and left SCTT. Significant time-by-treatment interaction was observed in the RMD group for stool volume (p = 0.014), increasing 56 % compared to baseline (p < 0.01), while remained unchanged in the placebo group. Stool consistency was improved only in the RMD group (p < 0.01). No adverse effects related to study products were observed. CONCLUSIONS: The results show that RMD improved CTT, stool volume, stool consistency and some intestinal functions in a healthy population.

Soluble plantain nonstarch polysaccharides, although increasing caecal load, reduce systemic invasion of Salmonella Gallinarum in the chicken.

UNLABELLED: Soluble plantain (Musa paradisiaca) nonstarch polysaccharides (NSPs) have previously been shown to prevent pathogenic interaction with the intestinal epithelium. Here, we examined whether plantain NSP could prevent the invasion of the intestinal mucosa by Salmonella enterica Gallinarum, a causative agent of fowl typhoid. In vitro assays using B1OXI cells were performed with monolayers pretreated with/without plantain NSP, before inoculation with Salm. Gallinarum 287/91. Chicks were fed from hatch on a pellet diet containing 50 mg day(-1) plantain NSP, followed by oral inoculation with Salm. Gallinarum 287/91 at the age of 6 days. Bacteria were enumerated from the liver, spleen and caecal contents 3 days postinfection. Adhesion and invasion of Salm. Gallinarum to B1OXI cells were inhibited by 10 mg ml(-1) plantain NSP (reduction in invasion 52%; 95% CI 27-77; P < 0.05). In vivo diet supplemented with 50 mg day(-1) plantain NSP reduced the invasion of Salm. Gallinarum in the chick liver (control 4.05 Log10 CFU g(-1) , SE 0.28, vs plantain 2.07 Log10 CFU g(-1) , SE 0.65; P < 0.01) and nonsignificantly in the spleen. Conversely, CFUs were significantly increased in the caeca (control 1.27 Log10 CFU g(-1), SE 0.65, vs plantain 6.04 Log10 CFU g(-1) , SE 0.17; P < 0.001). Plantain NSP feed reduced the systemic infection by Salm. Gallinarum and may have potential in reducing the impact of the disease in avian salmonellosis. The caveat is the increased caecal load of Salm. Gallinarum, although this may reflect both the reduced intestinal invasion and the bacterial multiplication in the caeca. SIGNIFICANCE AND IMPACT OF THE STUDY: Nonstarch polysaccharide (NSP) derived from the plantain (Musa paradisiaca) inhibits interaction with epithelial cells by Salmonella enterica Gallinarum, a causative agent of the disease fowl typhoid. Incorporation of plantain NSP into the poultry feed reduced Salm. Gallinarum levels in the spleen and liver of chicks following experimental infection, although their numbers in the caeca increased. These data demonstrate that alternatives to antimicrobials such as NSP may be useful in the control of invasive salmonellosis in poultry.

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

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

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

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

Soluble Non-Starch Polysaccharides From Plantain (Musa x paradisiaca L.) Diminish Epithelial Impact of Clostridioides difficile.

Clostridioides difficile infection (CDI) is a leading cause of antibiotic-associated diarrhoea. Adhesion of this Gram-positive pathogen to the intestinal epithelium is a crucial step in CDI, with recurrence and relapse of disease dependent on epithelial interaction of its endospores. Close proximity, or adhesion of, hypervirulent strains to the intestinal mucosa are also likely to be necessary for the release of C. difficile toxins, which when internalized, result in intestinal epithelial cell rounding, damage, inflammation, loss of barrier function and diarrhoea. Interrupting these C. difficile-epithelium interactions could therefore represent a promising therapeutic strategy to prevent and treat CDI. Intake of dietary fibre is widely recognised as being beneficial for intestinal health, and we have previously shown that soluble non-starch polysaccharides (NSP) from plantain banana (Musa spp.), can block epithelial adhesion and invasion of a number of gut pathogens, such as E. coli and Salmonellae. Here, we assessed the action of plantain NSP, and a range of alternative soluble plant fibres, for inhibitory action on epithelial interactions of C. difficile clinical isolates, purified endospore preparations and toxins. We found that plantain NSP possessed ability to disrupt epithelial adhesion of C. difficile vegetative cells and spores, with inhibitory activity against C. difficile found within the acidic (pectin-rich) polysaccharide component, through interaction with the intestinal epithelium. Similar activity was found with NSP purified from broccoli and leek, although seen to be less potent than NSP from plantain. Whilst plantain NSP could not block the interaction and intracellular action of purified C. difficile toxins, it significantly diminished the epithelial impact of C. difficile, reducing both bacteria and toxin induced inflammation, activation of caspase 3/7 and cytotoxicity in human intestinal cell-line and murine intestinal organoid cultures. Dietary supplementation with soluble NSP from plantain may therefore confer a protective effect in CDI patients by preventing adhesion of C. difficile to the mucosa, i.e. a "contrabiotic" effect, and diminishing its epithelial impact. This suggests that plantain soluble dietary fibre may be a therapeutically effective nutritional product for use in the prevention or treatment of CDI and antibiotic-associated diarrhoea.

Valorisation of Sea Buckthorn Pomace by Optimization of Ultrasonic-Assisted Extraction of Soluble Dietary Fibre Using Response Surface Methodology.

Sea buckthorn pomace is a valuable industrial waste/by-product obtained after juice production that contains bioactive, health-promoting dietary fibres. This pomace finds usage as animal feed or simply discarded, owed to the lack of appropriate handling or processing facilities. The present study was aimed to evaluate the effects of green extraction technologies such as ultrasonic-assisted extraction on the yield of soluble dietary fibre (SDF) from sea buckthorn pomace. Response surface methodology (RSM) coupled with Box-Behnken design (BBD) was applied for optimization of SDF yield. The effects of sonication temperature (60-80 °C), sonication power (100-130 W) and extraction time (30-60 min) on the yield of SDF were also investigated. Furthermore, colour measurement and hydration properties of sea buckthorn pomace powder (STP) and dietary fibre fractions (SDF and insoluble dietary fibre, IDF) were also investigated. From the RSM results, the optimal sonication temperature (67.83 °C), sonication power (105.52 W) and extraction time (51.18 min) were identified. Based on this, the modified optimum conditions were standardised (sonication temperature of 70 °C, sonication power of 105 W and extraction time of 50 min). Accordingly, the yield of SDF obtained was 16.08 ± 0.18%, which was close to the predicted value (15.66%). Sonication temperature showed significant effects at p ≤ 0.01, while sonication power and extraction time showed significant effects at p ≤ 0.05 on the yield of SDF. The result on colour attributes of STP, SDF and IDF differed (L* (STP: 54.71 ± 0.72, IDF: 72.64 ± 0.21 and SDF: 54.53 ± 0.31), a* (STP: 52.35 ± 1.04, IDF: 32.85 ± 0.79 and SDF: 43.54 ± 0.03), b* (STP: 79.28 ± 0.62, IDF: 82.47 ± 0.19 and SDF: 71.33 ± 0.50), and ∆E* (STP: 79.93 ± 0.50, IDF: 74.18 ± 0.30 and SDF: 68.40 ± 0.39)). Higher values of hydration properties such as the water holding, swelling and oil holding capacities were found in SDF (7.25 ± 0.10 g g-1, 7.24 ± 0.05 mL g-1 and 1.49 ± 0.02 g g-1), followed by IDF (6.30 ± 0.02, 5.75 ± 0.07 and 1.25 ± 0.03) and STP (4.17 ± 0.04, 3.48 ± 0.06 and 0.89 ± 0.03), respectively. Based on our results, response surface methodology is recommended to be adopted to optimize the ultrasonic-assisted extraction to obtain maximum yield of SDF from sea buckthorn pomace. These results can be of practical usage while designing future functional food formulations using sea buckthorn pomace.

High methoxyl pectin from the soluble dietary fiber of passion fruit peel forms weak gel without the requirement of sugar addition.

Passion fruit peel (PFP) is a by-product from the fruit processing industry, accounting for approximately 50 % of the fruit weight. It is well known for its health properties, although few studies evaluated its rheological properties. PFP polysaccharides (PFPP) contain a high methoxyl pectin (HMP), specifically a 70 % methyl-esterified homogalacturonan. Flow behaviour analysis of PFPP (with or without sucrose) revealed a shear-thinning non-Newtonian behaviour. Dynamic oscillatory tests showed a weak gel-like behaviour, even without sucrose addition. Moreover, under simulated pasteurization process PFPP maintained its gel structure. Taken together we demonstrated that PFPP has divergent behaviour from commercial HMP, since it does not require sucrose or low pH to form gel. The present work reinforces the use of PFP as a source of soluble dietary fibres and pectins, providing its alternative application as a rheological modifier in a wide range of products, including those with low sugar.

Mechanism of lipid metabolism regulation by soluble dietary fibre from micronized and non-micronized powders of lotus root nodes as revealed by their adsorption and activity inhibition of pancreatic lipase.

Soluble dietary fibre (SDF) of micronized and non-micronized powders of lotus root nodes were investigated based on its adsorption and activity inhibition of pancreatic lipase (PL) by using circular dichroism, fluorescence spectroscopy and modification. Results showed that SDF2 (SDF from micronized powders of lotus root nodes) had stronger PL adsorption and enzyme activity inhibition than SDF1 (SDF from non-micronized powders of lotus root nodes). Specifically, SDF2 showed more binding sites than SDF1 in PL. There were hydrogen bonds and van der Waals interactions between SDF and PL, with Trp on PL probably serving as the main binding site. Carboxyl groups exhibited a stronger inhibition on PL by carboxymethyl and hydroxypropyl modification. The common mechanisms between SDF1 and SDF2 can be attributed to the combination between Trp and carboxyl groups, while the differences may be generated by the variations in structures or chemical groups induced by micronization.

Comparison of the adsorption behaviour of catechin onto cellulose and pectin.

The adsorption behaviour of catechin onto cellulose and pectin was compared. The adsorption of catechin onto the two fibres involved an initial fast adsorption phase followed by a slower adsorption as the sites became saturated and the systems moved towards equilibrium. The adsorption capacity of pectin for catechin (20.71 ±â€¯2.24 mg/g) was significantly greater than that of cellulose (2.41 ±â€¯0.05 mg/g) after equilibration for 24 h at 37 °C. The Langmuir and Freundlich models were applied to obtain the quantitative information about the adsorption of catechins to pectin and cellulose. Thermodynamic data derived from the isothermal adsorption carried out at the temperatures of 27 °C, 32 °C, 37 °C and 42 °C suggested that the adsorption was spontaneous and the binding was driven predominantly by physisorption. Fluorescence experiments confirmed the adsorption of catechins onto cellulose and pectin. The results showed that catechin adsorption capacity and adsorption mechanism were different for pectin and cellulose.

Unravelling the Effects of Soluble Dietary Fibre Supplementation on Energy Intake and Perceived Satiety in Healthy Adults: Evidence from Systematic Review and Meta-Analysis of Randomised-Controlled Trials.

Consumption of soluble dietary fibre is recommended as part of a healthy diet. Evidence has shown that soluble dietary fibre slows gastric emptying, increases perceived satiety and plays a significant role in appetite regulation. This systematic review examined the effects of soluble dietary fibre using randomised-controlled trials (RCTs). Three different electronic databases were used, namely PubMed, Scopus® and the Cochrane Central Register of Controlled Trials (CENTRAL). Effect size (Cohen's d) was calculated based on the intergroup mean difference and standard deviation (SD) followed by Cochran's Q and I² determination. The effect size was statistically pooled in the meta-analyses and presented as a forest plot. The risk of bias was high for each study as assessed using the Jadad scale. Meta-analysis of statistically pooled data for guar gum showed a sizeable effect on post-meal energy intake, followed by ß-glucan, alginate, polydextrose and pectin, with pooled effect sizes of -0.90, -0.44, -0.42, -0.36 and -0.26, respectively. Guar gum (5 g) effectively reduced energy intake when prepared in milk beverages compared with control milk (p < 0.001). Alginate, when prepared in liquid (5 g) or solid (9 g) meals, effectively reduced energy intake compared with control (p < 0.001). A high dose of polydextrose (25 g) prepared in liquid meal form significantly reduced energy intake (p = 0.01). This study suggests that soluble fibres are not all created equal. Further interventional studies are needed to determine whether combinations of these soluble fibres might have greater effects than individual fibres per se.

Texture and mouthfeel perceptions of a model beverage system containing soluble and insoluble oat bran fibres.

Dietary fibre fortified products have increased in popularity as health-conscious consumers seek convenient ways to increase fibre intake. Fibres from wholegrains are particularly desirable inclusions in food products because of their proven physiological health-benefits. When fortifying beverages with fibre, however, the insoluble dietary fibre components present in wholegrains often contribute to unpleasant gritty sensations making the products unpalatable. Consequently, designing wholegrain-fortified beverages with sufficient fibre-content to make health related fibre claims is a major challenge in the food manufacturing industry. This work aims to take a systematic approach in identifying the texture/mouthfeel related sensory impact and interaction between two commercial oat fibre ingredients (Oatwell28XF® and Milled Oats) when added to a model beverage system. Eighteen samples were prepared containing either or both the ingredients, at varying levels, and were assessed by a trained panel using conventional sensory descriptive techniques. The results indicate that the two different oat bran fibres produced distinct mouthfeel perceptions which could be attributed to the varying soluble and insoluble fibre content of the samples. Insoluble dietary fibre concentrations above 2% (w/w) resulted in particle-related sensory properties chalkiness, dryness and particle perception, which dominated the overall mouthfeel and textural sensory perception of the samples. Samples with predominantly soluble ß-glucan, resulted in perceptions of smoothness, sliminess and stickiness residue, while thickness, mouthcoating and cloying sensations were driven by total fibre concentration, irrespective of fibre solubility. This work provides a solid foundation for food manufacturers aiming to rationally design and develop nutritionally superior fibre-fortified beverages and is relevant to fibre content concentrations required for labelling/nutrition claims for consumer products in many developed nations.

Characterisation of physicochemical and functional properties of soluble dietary fibre from potato pulp obtained by enzyme-assisted extraction.

In this study, enzyme-assisted methodology was applied with the aim to optimise the efficiency of soluble dietary fibre (SDF) extraction from potato pulp. The yields of SDF pretreated by cellulase, xylanase, and a cellulase/xylanase mixture were 31.9% (w/w), 25.7% (w/w), and 39.7% (w/w) respectively. When comparing single enzyme pretreatment with combined enzymatic treatment, we observed differences in properties related to molecular weight and viscosity. SDF obtained by xylanase pretreatment rendered better results for glucose dialysis retardation index (32.98%, w/w), amylase inhibitory effect (56.2%), and pancreatic lipase inhibitory activity (55.33%), while combined enzymatic pretreatment exhibited better effect in properties related to exposure of functional groups and specific surface area, including sodium cholate binding capacity (72.2%) and hydroxyl radical scavenging activity (87.57%). Our results indicated that enzymatic pretreatment, which could effectively hydrolyse cellulose and hemicellulose components, could not only benefit the yield of SDF, but also enhance its physiological and functional properties.

Non-destructive determination and visualisation of insoluble and soluble dietary fibre contents in fresh-cut celeries during storage periods using hyperspectral imaging technique.

The feasibility of using hyperspectral imaging technique to non-destructively determine insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) contents in fresh-cut celeries and visualise their spatial distribution during 28-day storage periods was investigated. Genetic synergy interval partial least square (GA-Si-PLS) algorithm was developed to establish calibration model, which, superior to the PLS and Si-PLS developed models, achieved the prediction performance with Rp of 0.9638 and 0.9756, and RMSEP of 1.180 and 0.336, respectively. The developed GA-Si-PLS models were then applied pixel-wise to visualise the spatial distribution of IDF and SDF contents during storage, which clearly showed that the IDF content increased with storage time, while the SDF content kept decreasing. The study provides the basis for further understanding of the spatial-temporal variation of IDF and SDF contents during storage, demonstrating that HSI could be useful in real-time IDF and SDF contents monitoring in vegetable research and industry.