Weight, habitual fibre intake, and microbiome composition predict tolerance to fructan supplementation.

Fructans are commonly used as dietary fibre supplements for their ability to promote the growth of beneficial gut microbes. However, fructan consumption has been associated with various dosage-dependent side effects. We characterised side effects in an exploratory analysis of a randomised trial in healthy adults (n = 40) who consumed 18 g/day inulin or placebo. We found that individuals weighing more or habitually consuming higher fibre exhibited the best tolerance. Furthermore, we identified associations between gut microbiome composition and host tolerance. Specifically, higher levels of Christensenellaceae R-7 group were associated with gastrointestinal discomfort, and a machine-learning-based approach successfully predicted high levels of flatulence, with [Ruminococcus] torques group and (Oscillospiraceae) UCG-002 sp. identified as key predictive taxa. These data reveal trends that can help guide personalised recommendations for initial inulin dosage. Our results support prior ecological findings indicating that fibre supplementation has the greatest impact on individuals whose baseline fibre intake is lowest.

Reply to "Stribling & Ibrahim 2023: Commentary to the Editor".

In response to "Stribling & Ibrahim 2023: Commentary to the Editor", we wish to thank all authors for their interest in our work. The sole motive behind our narrative review, after learning the lesson from the trans-fat history and its impact on the science and food industry, is to prevent harm before it is too late. We agree with the authors regarding the importance of a worldwide unified definition of dietary fibre, but this should not have potential to worsen symptoms of those with functional bowel disorders nor cause more confusion among the public regarding the health benefits of dietary fibre. Thus, we aim to address the authors' views and concerns, and to provide future recommendations, which will be summarised below. The following abbreviations will be used: FBDs, functional bowel disorders; DF, dietary fibre; LMW DF, low molecular weight dietary fibre; HMW DF, high molecular weight dietary fibre.

Impact of Simulated Human Gastrointestinal Digestion on the Functional Properties of Dietary Fibres Obtained from Broccoli Leaves, Grape Stems, Pomegranate and Tomato Peels.

This study aimed to analyse the impact of a simulated human digestion process on the composition and functional properties of dietary fibres derived from pomegranate-peel, tomato-peel, broccoli-stem and grape-stem by-products. For this purpose, a computer-controlled simulated digestion system consisting of three bioreactors (simulating the stomach, small intestine and colon) was utilised. Non-extractable phenols associated with dietary fibre and their influence on antioxidant capacity and antiproliferative activity were investigated throughout the simulated digestive phases. Additionally, the modifications in oligosaccharide composition, the microbiological population and short-chain fatty acids produced within the digestion media were examined. The type and composition of each dietary fibre significantly influenced its functional properties and behaviour during intestinal transit. Notably, the dietary fibre from the pomegranate peel retained its high phenol content throughout colon digestion, potentially enhancing intestinal health due to its strong antioxidant activity. Similarly, the dietary fibre from broccoli stems and pomegranate peel demonstrated anti-proliferative effects in both the small and the large intestines, prompting significant modifications in colonic microbiology. Moreover, these fibre types promoted the growth of bifidobacteria over lactic acid bacteria. Thus, these results suggest that the dietary fibre from pomegranate peel seems to be a promising functional food ingredient for improving human health.

Probabilistic Modelling of the Food Matrix Effects on Curcuminoid's In Vitro Oral Bioaccessibility.

The bioaccessibility of bioactive compounds plays a major role in the nutritional value of foods, but there is a lack of systematic studies assessing the effect of the food matrix on bioaccessibility. Curcuminoids are phytochemicals extracted from Curcuma longa that have captured public attention due to claimed health benefits. The aim of this study is to develop a mathematical model to predict curcuminoid's bioaccessibility in biscuits and custard based on different fibre type formulations. Bioaccessibilities for curcumin-enriched custards and biscuits were obtained through in vitro digestion, and physicochemical food properties were characterised. A strong correlation between macronutrient concentration and bioaccessibility was observed (p = 0.89) and chosen as a main explanatory variable in a Bayesian hierarchical linear regression model. Additionally, the patterns of food matrix effects on bioaccessibility were not the same in custards as in biscuits; for example, the hemicellulose content had a moderately strong positive correlation to bioaccessibility in biscuits (p = 0.66) which was non-significant in custards (p = 0.12). Using a Bayesian hierarchical approach to model these interactions resulted in an optimisation performance of r2 = 0.97 and a leave-one-out cross-validation score (LOOCV) of r2 = 0.93. This decision-support system could assist the food industry in optimising the formulation of novel food products and enable consumers to make more informed choices.

Development of a protocol for fractionating and characterising fibres from lignocellulosic food waste.

This study aims to explore an advanced protocol for characterising dietary fibre (DF) fractions to meet the growing demand for accurate and reliable data. Although current enzymatic-gravimetric approaches, e.g., AOAC and Van Soest analysis, provide information about soluble and insoluble DF quantification, they present limitations related to the lack of fractions characterisation. To overcome these limitations, the proposed protocol integrates the official AOAC 991.43 method with the sequential fibre fractionation by exploiting the different resistance of the fibre fractions to acid hydrolysis treatments (TFA and H2SO4), utilising hazelnut shells as a case-study. Each hydrolysed fraction was quantified and characterised through GC-MS analysis of monosaccharides. The data obtained for hemicellulose, cellulose, and lignin fractions were then discussed and compared with the Van Soest method. This approach yields a comprehensive procedure applicable to different food and nutraceutical products, emphasising the importance of DF characterisation for a deeper understanding of their bio-functional properties.

Microbiota of healthy dogs demonstrate a significant decrease in richness and changes in specific bacterial groups in response to supplementation with resistant starch, but not psyllium or methylcellulose, in a randomized cross-over trial.

Even though dietary fibres are often used as prebiotic supplements in dogs, the effect of individual types of fibres on canine microbiota composition is unknown. The objective of this study was to assess changes in faecal microbiota richness, diversity and taxonomic abundance with three different fibre supplements in dogs. These were psyllium husk, resistant starch from banana flour and methylcellulose. They were administered to 17 healthy dogs in a cross-over trial after transition to the same complete feed. Faecal scores and clinical activity indices were recorded, and faecal samples were collected before and at the end of supplementation, as well as 2 weeks after each supplement (washout). Illumina NovaSeq paired-end 16S rRNA gene sequencing was performed on all samples. After quality control and chimera removal, alpha diversity indices were calculated with QIIME. Differences in specific taxa between groups were identified using Metastats. Methylcellulose significantly increased faecal scores but had no effect on microbiota. Psyllium resulted in minor changes in the abundance of specific taxa, but with questionable biological significance. Resistant starch reduced microbiota richness and resulted in the most abundant changes in taxa, mostly a reduction in short-chain fatty acid-producing genera of the phylum Bacillota, with an increase in genera within the Bacteroidota, Pseudomonadota, Actinomycetota and Saccharibacteria. In conclusion, while psyllium and methylcellulose led to few changes in the microbiota composition, the taxonomic changes seen with resistant starch may indicate a less favourable composition. Based on this, the type of resistant starch used here cannot be recommended as a prebiotic in dogs.

Impact of chickpea hummus on postprandial blood glucose, insulin and gut hormones in healthy humans combined with mechanistic studies of food structure, rheology and digestion kinetics.

Slowing the rate of carbohydrate digestion leads to low postprandial glucose and insulin responses, which are associated with reduced risk of type 2 diabetes. There is increasing evidence that food structure plays a crucial role in influencing the bioaccessibility and digestion kinetics of macronutrients. The aims of this study were to compare the effects of two hummus meals, with different degrees of cell wall integrity, on postprandial metabolic responses in relation to the microstructural and rheological characteristics of the meals. A randomised crossover trial in 15 healthy participants was designed to compare the acute effect of 27 g of starch, provided as hummus made from either intact chickpea cells (ICC) or ruptured chickpea cells (RCC), on postprandial metabolic responses. In vitro starch digestibility, microstructural and rheological experiments were also conducted to evaluate differences between the two chickpea hummus meals. Blood insulin and GIP concentrations were significantly lower (P < 0.02, P < 0.03) after the consumption of the ICC meal than the meal containing RCC. In vitro starch digestion for 90 min was slower in ICC than in RCC. Microscopic examination of hummus samples digested in vitro for 90 min revealed more intact chickpea cells in ICC compared to the RCC sample. Rheological experiments showed that fracture for ICC hummus samples occurred at smaller strains compared to RCC samples. However, the storage modulus for ICC was higher than RCC, which may be explained by the presence of intact cells in ICC. Food structure can affect the rate and extent of starch bioaccessibility and digestion and may explain the difference in the time course of metabolic responses between meals. The rheological properties were measured on the two types of meals before ingestion, showing significant differences that may point to different breakdown mechanisms during subsequent digestion. This trial was registered at clinicaltrial.gov as NCT03424187.

Analysing the Impact of Resistant Starch Formation in Basmati Rice Products: Exploring Associations with Blood Glucose and Lipid Profiles across Various Cooking and Storage Conditions In Vivo.

Common cooking methods were used to prepare basmati rice products, including boiling 1 (boiling by absorption), boiling 2 (boiling in extra amount of water), frying, and pressure cooking. The cooked rice was held at various temperatures and times as follows: it was made fresh (T1), kept at room temperature (20-22 °C) for 24 h (T2), kept at 4 °C for 24 h (T3), and then reheated after being kept at 4 °C for 24 h (T4). The proximate composition, total dietary fibre, resistant starch (RS), and in vitro starch digestion rate of products were examined. The effect of RS on blood glucose and lipid profiles was measured in humans and rats, including a histopathological study of the liver and pancreas in rats. The basmati rice that was prepared via boiling 1 and stored with T3 was found to be low in glycaemic index and glycaemic load, and to be high in resistant starch. Similarly, in rats, the blood glucose level, cholesterol, triglycerides, and LDL were reduced by about 29.7%, 37.9%, 31.3%, and 30.5%, respectively, after the consumption of basmati rice that was prepared via boiling 1 and stored with T3. Awareness should be raised among people about the health benefits of resistant starch consumption and the right way of cooking.

Performance and nutrient digestibility of growing pigs fed highly or low fermentable coarse or finely ground fibre-rich feedstuffs.

Dietary fibre is mainly classified according to its chemical characteristics but structure and particle size of fibre-rich feedstuff can also be decisive for digestion and performance. So far, only few studies investigated this in pigs. This experiment aimed to compare coarse and finely ground dried hemp plants and apple pomace regarding performance and ileal and total tract nutrient digestibility of growing pigs. Coarse or finely ground apple pomace or dried hemp plants were added to the diet of 56 nine weeks old growing pigs (DanBred x Duroc), housed in flat decks with each 2 animals. The growing pigs received the experimental diets for three weeks while performance was recorded. Eight pigs per group were sacrificed and digesta and organ tissue sampled. The stomach health was evaluated by visually scoring of the mucosa integrity. Apparent ileal (AID) and total tract digestibility (ATTD) were calculated using titanium dioxide as marker. Statistical analyses were performed using two-way ANOVA (p < 0.05). The highest feed intake (fibre particle size, p = 0.018) and bodyweight gain (fibre particle size, p = 0.018; fibre source x particle size interaction, p = 0.040), was observed in animals fed finely ground apple pomace, while the feed conversion ratio was 8-12% lower in pigs fed finely ground fibre sources (p = 0.012). No differences in stomach mucosa integrity were detected between the groups. The relative pancreas (p = 0.045), stomach (p < 0.001), and jejunum (p = 0.010) weights were higher in animals fed diets containing apple pomace. In contrast, the relative liver, caecum and colon weights were not affected by fibre source or particle size. The AID of protein and amino acids was not affected, while ATTD was increased by fibre source (hemp vs. apple pomace) reducing faecal nitrogen excretion. The AID of calcium was increased when diets contained apple pomace (p < 0.001), while zinc AID and ATTD were enhanced when diets contained dried hemp (p = 0.016; p = 0.016, respectively). Our results suggest that the structure as well as the chemical characteristics should be considered in a future fibre evaluation system in pigs.

Quantitative management of human faecal bulking response to combinations of functionally distinct dietary fibers, using functional equivalents and a validated rat model.

Functionally distinct dietary fibre sources may be combined in reformulated foods to restore a natural spectrum of health attributes. Effects of wheat bran (WB), psyllium husk, guar gum and Raftilose™ combinations on hydrated faecal mass (HFM), were determined. A valid rat model was fed diets supplemented with 10% WB, 10% WB with 1-6% psyllium in 1% steps, and 10% WB/5% psyllium with 1-7% guar gum or 1-6% Raftilose in 1% steps. Fully hydrated faecal pellets gave HFM values in the human range, increasing by 2.4 ± 0.29 g per gram of WB ingested, and by 15.6 ± 1.52 g per g of psyllium. Equations for incremental changes in HFM predicted intakes of fibre combinations required for adequate daily HFM, and it is shown how expressing relative effects of foods on HFM as functional equivalents would allow quantitative personalised management of HFM for reduced constipation and colorectal cancer in humans.

The effects of cereal ß-glucans on cardiovascular risk factors and the role of the gut microbiome.

The human gut microbiome has emerged as a key influencer of human health and disease, particularly through interactions with dietary fiber. However, national dietary guidelines worldwide are only beginning to capitalize on the potential of microbiome research, which has established the vital role of host-microbe interactions in mediating the physiological effects of diet on overall health and disease. ß-glucans have been demonstrated to modulate the composition of the gut microbiota, leading to improved outcomes in cardiovascular disease (CVD). Raised serum cholesterol and blood pressure are important modifiable risk factors in the development of CVD and emerging evidence highlights the role of the gut microbiota in ameliorating such biomarkers and clinical characteristics of the disease. The proposed mechanism of action of ß-glucans on the pathophysiological mechanisms of disease have yet to be elucidated. Validating gaps in the literature may substantiate ß-glucans as a potential novel dietary therapy against modifiable risk factors for CVD and would further support the public health significance of including a habitual fiber-rich diet.

Enrichment of vegan gluten-free pasta with basil seeds: Cooking quality, nutritional and antioxidant properties.

The germinated clove basil (Ocimum gratissimum) and sweet basil (Ocimum basilicum) seeds being a potent source of dietary fibre, minerals and antioxidants are utilized as functional ingredients for the enrichment of gluten-free pasta. The germinated clove basil seed and sweet basil seed incorporated pastas with acceptable sensory scores were developed by substituting 30% and 15% of gluten-free flour respectively. Basil seed pastas exhibited lesser cooking time (7-8 min), cooking loss (6%) and similar texture as that of control. The clove basil seed pasta exhibited better cooking quality, nutritional and antioxidant properties than the sweet basil seed pasta due to higher level of basil seed flour substitution. Consumption of one serving of clove basil seed pasta (75 g) could meet the dietary fibre (49%, 58%), protein (15%, 17%), magnesium (18%, 21%), phosphorus (22%, 22%), manganese (28%, 28%) and copper (28%, 28%) daily requirements of sedentary adult men and women, respectively.

Dietary fibre supplementation enhances radiotherapy tumour control and alleviates intestinal radiation toxicity.

BACKGROUND: Non-toxic approaches to enhance radiotherapy outcomes are beneficial, particularly in ageing populations. Based on preclinical findings showing that high-fibre diets sensitised bladder tumours to irradiation by modifying the gut microbiota, along with clinical evidence of prebiotics enhancing anti-cancer immunity, we hypothesised that dietary fibre and its gut microbiota modification can radiosensitise tumours via secretion of metabolites and/or immunomodulation. We investigated the efficacy of high-fibre diets combined with irradiation in immunoproficient C57BL/6 mice bearing bladder cancer flank allografts. RESULT: Psyllium plus inulin significantly decreased tumour size and delayed tumour growth following irradiation compared to 0.2% cellulose and raised intratumoural CD8+ cells. Post-irradiation, tumour control positively correlated with Lachnospiraceae family abundance. Psyllium plus resistant starch radiosensitised the tumours, positively correlating with Bacteroides genus abundance and increased caecal isoferulic acid levels, associated with a favourable response in terms of tumour control. Psyllium plus inulin mitigated the acute radiation injury caused by 14 Gy. Psyllium plus inulin increased caecal acetate, butyrate and propionate levels, and psyllium alone and psyllium plus resistant starch increased acetate levels. Human gut microbiota profiles at the phylum level were generally more like mouse 0.2% cellulose profiles than high fibre profiles. CONCLUSION: These supplements may be useful in combination with radiotherapy in patients with pelvic malignancy. Video Abstract.

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.

Quality of High-Fibre Pasta Supplemented with Watermelon Rind Powder with Different Particle Sizes.

Research background: Watermelon rind, a by-product of watermelon juice processing, contains large amounts of dietary fibre and phenols with antioxidant capacity. The use of agro-industrial by-products would both improve economic benefits and reduce environmental emissions. The aim of this research is to examine the effect of the particle size of watermelon rind powder on the quality of high-fibre pasta. Experiment approach: The nutritional, physical and physicochemical quality of three samples of watermelon rind powder, sieved through three sieves with aperture size of 400, 210 and 149 µm, were analysed. Durum wheat semolina with watermelon rind powder mass fraction of 10 % were mixed and used to make pasta. Nutritional, textural and cooking quality, sensory acceptability, in vitro glycaemic index and antioxidant bioaccessibility of high-fibre pasta with added watermelon rind powder of different particle sizes were evaluated and compared. Results and conclusions: When the sieve aperture size was reduced from 400 to 149 µm, the soluble dietary fibre and total phenolic contents of watermelon rind powder were increased by 35 and 15 %, respectively, while its insoluble dietary fibre content was decreased by 21 %. Decrease in sieve aperture size from 410 to 149 µm reduced phenolic bioaccessibility of the fortified pasta from 63 to 57 %, but enhanced its predicted glycaemic index from 50 to 69. It also decreased the pasta hardness by 13 %, but improved its elongation rate and tensile strength by 13 and 40 %, respectively. The finer the particles of the watermelon rind powder, the longer the optimal cooking time, the higher the water absorption index, and the lower the cooking loss of the supplemented pasta. Consumers did not notice any significant differences in the overall acceptability among all pasta samples. Novelty and scientific contribution: The particle size of the watermelon rind powder had a major effect on nutritional value, texture and cooking quality of the fortified pasta. In particular, the predicted glycaemic index and antioxidant bioaccessibility of high-fibre pasta were significantly affected by the particle size of the dietary fibre material used in the recipe.

Influence of seaweed dietary fibre as a potential alternative to phosphates on the quality profiles and flavour attributes of frankfurters.

This study primarily aimed to investigate the influence of seaweed dietary fibre (SDF), as a potential alternative to phosphates, on the quality profiles and flavour attributes of frankfurters. The results revealed that SDF addition can significantly improve the cooking yield and texture characteristics of phosphate-free frankfurters (P < 0.05), and 1.00% SDF proved to be the optimal concentration for replacing phosphates in frankfurters. Moreover, electronic nose and electronic tongue analyses demonstrated that SDF incorporation potentially influences the aroma and taste of phosphate-free frankfurters. Furthermore, volatile compound analysis revealed that SDF addition potentially compensates for the decrease in volatile flavour compound content caused by phosphate deficiency. Generally, our results indicate that SDF can be successfully applied as a potential alternative to phosphates and subsequently improve the quality profiles and flavour attributes of phosphate-free frankfurters. Moreover, they provide valuable theoretical guidance for the processing of phosphate-free emulsified meat products.

Role of the intestinal microbiota and diet in the onset and progression of colorectal and breast cancers and the interconnection between both types of tumours.

Colorectal cancer (CRC) is among the leading causes of mortality in adults of both sexes worldwide, while breast cancer (BC) is among the leading causes of death in women. In addition to age, gender, and genetic predisposition, environmental and lifestyle factors exert a strong influence. Global diet, including alcohol consumption, is one of the most important modifiable factors affecting the risk of CRC and BC. Western dietary patterns promoting high intakes of xenobiotics from food processing and ethanol have been associated with increased cancer risk, whereas the Mediterranean diet, generally leading to a higher intake of polyphenols and fibre, has been associated with a protective effect. Gut dysbiosis is a common feature in CRC, where the usual microbiota is progressively replaced by opportunistic pathogens and the gut metabolome is altered. The relationship between microbiota and BC has been less studied. The estrobolome is the collection of genes from intestinal bacteria that can metabolize oestrogens. In a dysbiosis condition, microbial deconjugating enzymes can reactivate conjugated-deactivated oestrogens, increasing the risk of BC. In contrast, intestinal microorganisms can increase the biological activity and bioavailability of dietary phytochemicals through diverse microbial metabolic transformations, potentiating their anticancer activity. Members of the intestinal microbiota can increase the toxicity of xenobiotics through metabolic transformations. However, most of the microorganisms involved in diet-microbiota interactions remain poorly characterized. Here, we provide an overview of the associations between microbiota and diet in BC and CRC, considering the diverse types and heterogeneity of these cancers and their relationship between them and with gut microbiota.

Enhancing water retention and mechanisms of citrus and soya bean dietary fibres in pre-fermented frozen dough.

In recent years, the production of prepared and frozen foods has increased with economic development. However, during freezing, moisture migration forms ice crystals that damage food structure and reduce quality. This study investigates moisture migration changes in pre-fermented dough during frozen storage and effectiveness of Citrus fibre (CF) and Soya dietary fibre (SDF) on quality improvement. Pre-fermented frozen dough properties were evaluated at different freezing storage days with CF and SDF. Results showed frozen storage reduced water retention, converting deeply bound water to weakly bound and free water. Freezable water content increased significantly from 53% (fresh) to 56.95% (60d-control), forming disruptive ice crystals in gluten protein structure. SDF had superior water flow restriction compared to CF, preventing large ice crystal accumulation, enhancing water-holding capacity, and maintaining gluten protein structure. These findings lay a theoretical foundation for improving quality and industrial applications of pre-fermented frozen dough.

Impact of Brewers' Spent Grain-Containing Biscuit on Postprandial Glycaemic Response in Individuals with Metabolic Syndrome: A Crossover Randomised Controlled Trial.

Brewers' spent grain (BSG) is a fibre and protein-rich by-product of beer-brewing. Fermenting BSG with Rhizopus oligosporus can further increase its content of soluble fibre, protein and certain antioxidants. Since nutrients rich in BSG can improve postprandial glycaemic response, this study assessed the postprandial glucose response (PPGR) and postprandial insulin response (PPIR) controlling effect of consuming 30% wheat flour substituted biscuits with autoclaved BSG (ABSG) or fermented BSG (FBSG) in individuals with metabolic syndrome (MetS). The effect on postprandial lipid panel, breath hydrogen (H2) and methane (CH4) concentration and subjective appetite response was also examined. Fifteen subjects with MetS participated in this crossover randomised controlled trial, and blood was collected at 9 time-points for 4 h after consumption of control biscuits (Control), ABSG and FBSG. A significant interaction effect was observed (Pinteraction = 0.013) for the glucose time-points concentration. At 180 min, the glucose concentration was lowered after the consumption of ABSG (p = 0.010) and FBSG (p = 0.012) compared to the Control. Moreover, the FBSG resulted in a significantly lower glucose incremental area under curve (iAUC) compared to the Control (p = 0.028). Insulin level was also lowered at 180 min after the ABSG (p = 0.010) and FBSG (p = 0.051) consumption compared to the Control. However, no difference was noted for postprandial lipid panel, breath H2 and CH4 concentration and subjective appetite response. In conclusion, the consumption of BSG-incorporated biscuits can attenuate PPGR, and fermented BSG incorporation conferred a further PPGR controlling benefit.

In vitro protein digestion and carbohydrate colon fermentation of microbial biomass samples from bacterial, filamentous fungus and yeast sources.

This study evaluated the nutritional quality of different microbial biomass samples by assessing their protein digestibility and carbohydrate fermentability in the colon using in vitro methods. Four microbial samples were produced: one hydrogen-oxidizing bacterial strain (Nocardioides nitrophenolicus KGS-27), two strains of filamentous fungi (Rhizopus oligosporus and Paecilomyces variotii), and one yeast strain (Rhodotorula babjevae). The microorganisms were grown in bioreactors, harvested and dried before analysis. The commercial fungal product Quorn was used as a reference. The protein digestibility of the microbial samples was analysed using the INFOGEST in vitro model, followed by quantification of N-terminal amine groups. An in vitro faecal fermentation experiment was also performed to evaluate the degradation of carbohydrates in microbial biomass samples and formation of short-chain fatty acids (SCFA). The fungal biomass samples had higher protein hydrolysis (60-75 %) than the bacterial sample (12 %) and Quorn (45 %), while the yeast biomass had the highest protein digestibility (85 %). Heat-treatment of the biomass significantly reduced its protein digestibility. Total dietary fibre (DF) content of fungal biomass was 31 - 43 %(DW), mostly insoluble, whereas the bacterial biomass contained mainly soluble DF (total DF: 25.7 %, of which 23.5 % were soluble and 2.2 % insoluble). After 24 h of colonic in vitro fermentation, SCFA production from the biomass of Paecilomyces, Quorn and Rhodotorula was similar to that of wheat bran, while 17 % and 32 % less SCFA were produced from the biomass of Rhizopus and the bacterial strain, respectively. Further studies are needed to clarify the reasons for the observed differences in protein digestibility and DF fermentability, especially regarding the cell wall structures and role of post-processing.