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Precision Microbiome Modulation with Discrete Dietary Fiber Structures Directs Short-Chain Fatty Acid Production.
Deehan, EC, Yang, C, Perez-Muñoz, ME, Nguyen, NK, Cheng, CC, Triador, L, Zhang, Z, Bakal, JA, Walter, J
Cell host & microbe. 2020;(3):389-404.e6
Abstract
Dietary fibers (DFs) impact the gut microbiome in ways often considered beneficial. However, it is unknown if precise and predictable manipulations of the gut microbiota, and especially its metabolic activity, can be achieved through DFs with discrete chemical structures. Using a dose-response trial with three type-IV resistant starches (RS4s) in healthy humans, we found that crystalline and phosphate cross-linked starch structures induce divergent and highly specific effects on microbiome composition that are linked to directed shifts in the output of either propionate or butyrate. The dominant RS4-induced effects were remarkably consistent within treatment groups, dose-dependent plateauing at 35 g/day, and can be explained by substrate-specific binding and utilization of the RS4s by bacterial taxa with different pathways for starch metabolism. Overall, these findings support the potential of using discrete DF structures to achieve targeted manipulations of the gut microbiome and its metabolic functions relevant to health.
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Active edible sugar palm starch-chitosan films carrying extra virgin olive oil: Barrier, thermo-mechanical, antioxidant, and antimicrobial properties.
Hasan, M, Rusman, R, Khaldun, I, Ardana, L, Mudatsir, M, Fansuri, H
International journal of biological macromolecules. 2020;:766-775
Abstract
Starch-chitosan blend films are considered promising raw materials for producing active food packaging film, especially by adding active compounds such as essential oil. Active edible sugar palm starch (SPS)-chitosan (CH) films carrying extra virgin olive oil (EVOO) were fabricated. Tensile strength (TS) and elongation at break (EB), thermal stability, barrier properties, antioxidant and antimicrobial activity of the CH/SPS-EVOO blend films are reported in this study. The structure of produced films associated with compatibility caused by interaction of film components were evaluated by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction. The increase in concentration of EVOO (extra virgin olive oil) in CH/SPS-EVOO blend films increased the thermal stability and antioxidant activity whereas reduction was observed on surface roughness. The addition of EVOO (2.0% w/w) in CH/SPS matrix increased the tensile strength (158.1%) and elongation at break (224.6%). The formation of hydrogen bonds between CH-SPS and EVOO blend was confirmed by the FTIR spectra. Experimental results indicated that the optimum EVOO content for the CH/SPS-based film was 2% w/w, so that the film possesses the potential for the intended application as an active biocomposite film and can replace the use of pure CH/SPS film.
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3.
Common buckwheat-resistant starch as a suitable raw material for food production: A structural and physicochemical investigation.
Gao, L, Xia, M, Li, Z, Wang, M, Wang, P, Yang, P, Gao, X, Gao, J
International journal of biological macromolecules. 2020;:145-153
Abstract
Heat-moisture treatment (HMT) of starch is defined as a physical method to change its properties. Compared with maize and potato, starches from common buckwheat (Xinong9976 and Pingqiao2) were isolated and its morphology and physicochemical properties investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), ATR-FTIR analysis, rapid viscosity analyzer (RVA) and differential scanning calorimeter (DSC) were studied before and after HMT. The experimental results showed that there were obvious differences between native starch (NS) and resistant starch (RS) of common buckwheat. HMT altered the A-type crystalline pattern and the degree of short-range order of common buckwheat starches and significantly decreased water solubility, swelling power (70-90 °C), freeze-thaw stability and pasting properties and increased oil and water absorption capacities, light transmittance as well as thermal stability. This study shows that the NS and RS of common buckwheat can be used as the suitable raw materials in food processing.
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4.
Dietary polyphenols modulate starch digestion and glycaemic level: a review.
Sun, L, Miao, M
Critical reviews in food science and nutrition. 2020;(4):541-555
Abstract
Polyphenols, as one group of secondary metabolite, are widely distributed in plants and have been reported to show various bioactivities in recent year. Starch digestion not only is related with food industrial applications such as brewing but also plays an important role in postprandial blood glucose level, and therefore insulin resistance. Many studies have shown that dietary phenolic extracts and pure polyphenols can retard starch digestion in vitro, and the retarding effect depends on the phenolic composition and molecular structure. Besides, dietary polyphenols have also been reported to alleviate elevation of blood glucose level after meal, indicating the inhibition of starch digestion in vivo. This review aims to analyze how dietary polyphenols affect starch digestion both in vitro and in vivo. We can conclude that the retarded starch digestion in vitro by polyphenols results from inhibition of key digestive enzymes, including α-amylase and α-glucosidase, as well as from interactions between polyphenols and starch. The alleviation of postprandial hyperglycemia by polyphenols might be caused by both the inhibited starch digestion in vivo and the influenced glucose transport. Therefore, phenolic extracts or pure polyphenols may be alternatives for preventing and treating type II diabetes disease.
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5.
Theoretical and experimental approaches to understand the biosynthesis of starch granules in a physiological context.
Pfister, B, Zeeman, SC, Rugen, MD, Field, RA, Ebenhöh, O, Raguin, A
Photosynthesis research. 2020;(1):55-70
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Abstract
Starch, a plant-derived insoluble carbohydrate composed of glucose polymers, is the principal carbohydrate in our diet and a valuable raw material for industry. The properties of starch depend on the arrangement of glucose units within the constituent polymers. However, key aspects of starch structure and the underlying biosynthetic processes are not well understood, limiting progress towards targeted improvement of our starch crops. In particular, the major component of starch, amylopectin, has a complex three-dimensional, branched architecture. This architecture stems from the combined actions of a multitude of enzymes, each having broad specificities that are difficult to capture experimentally. In this review, we reflect on experimental approaches and limitations to decipher the enzymes' specificities and explore possibilities for in silico simulations of these activities. We believe that the synergy between experimentation and simulation is needed for the correct interpretation of experimental data and holds the potential to greatly advance our understanding of the overall starch biosynthetic process. We furthermore propose that the formation of glucan secondary structures, concomitant with its synthesis, is a previously overlooked factor that directly affects amylopectin architecture through its impact on enzyme function.
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Effect of grapefruit seed extract ratios on functional properties of corn starch-chitosan bionanocomposite films for active packaging.
Jha, P
International journal of biological macromolecules. 2020;:1546-1556
Abstract
The objective of this research was to investigate the effect of different ratios of grapefruit seed extract (GFSE) on functional properties of bionanocomposite (BNC) films prepared with corn starch (CS) incorporated with chitosan (CH)-nanoclay. Experimental results exhibited that the addition of GFSE properly dispersed with CS combined with CH bionanocomposite films. The presence of GFSE from 0 to 1.5% v/v exhibited increase in crystallinity and TS while decease in EB, FS and WVP. Furthermore, an addition of 2%v/v GFSE revealed decrease in its physical properties. When bread samples were packed, synthetic plastic exhibited the proliferation of fungal growth in 6 days, whereas CS/CH/1.5% v/v GFSE bionanocomposite film exhibited the same for at least 20 days. This study presents that CS/CH/1.5% v/v GFSE nanoclay film could potentially be useful for novel eco-friendly active packaging for confectionary industries to extend the shelf life to maintain its quality and safety of food products.
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Dietary sugars and cardiometabolic risk factors: a network meta-analysis on isocaloric substitution interventions.
Schwingshackl, L, Neuenschwander, M, Hoffmann, G, Buyken, AE, Schlesinger, S
The American journal of clinical nutrition. 2020;(1):187-196
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Abstract
BACKGROUND There is controversy on the relevance of dietary sugar intake for cardiometabolic health. OBJECTIVE The aim of this network meta-analysis (NMA) was to assess how isocaloric substitutions of dietary sugar with other carbohydrates affect cardiometabolic risk factors, comparing different intervention studies. METHODS We included randomized controlled trials (RCTs) investigating the isocaloric effect of substituting dietary sugars (fructose, glucose, sucrose) with other sugars or starch on cardiometabolic risk markers, including LDL cholesterol, triacylglycerol (TG), fasting glucose (FG), glycated hemoglobin (HbA1c), insulin resistance (HOMA-IR), uric acid, C-reactive protein (CRP), alanine transaminase (ALT), aspartate transaminase (AST), and liver fat content. To identify the most beneficial intervention for each outcome, random-effects NMA was conducted by calculating pooled mean differences (MDs) with 95% CIs, and by ranking the surface under the cumulative ranking curves (SUCRAs). The certainty of evidence was evaluated using the Confidence In Network Meta-Analysis tool. RESULTS Thirty-eight RCTs, including 1383 participants, were identified. A reduction in LDL-cholesterol concentrations was shown for the exchange of sucrose with starch (MD: -0.23 mmol/L; 95% CI: -0.38, -0.07 mmol/L) or fructose with starch (MD: -0.22 mmol/L; 95% CI: -0.39, -0.05 mmol/L; SUCRAstarch: 98%). FG concentrations were also lower for the exchange of sucrose with starch (MD: -0.14 mmol/L; 95% CI: -0.29, 0.01 mmol/L; SUCRAstarch: 91%). Replacing fructose with an equivalent energy amount of glucose reduced HOMA-IR (MD: -0.36; 95% CI: -0.71, -0.02; SUCRAglucose: 74%) and uric acid (MD: -23.77 µmol/L; 95% CI: -44.21, -3.32 µmol/L; SUCRAglucose: 93%). The certainty of evidence was rated very low to moderate. No significant effects were observed for TG, HbA1c, CRP, ALT, and AST. CONCLUSIONS Our findings indicate that substitution of sucrose and fructose with starch yielded lower LDL cholesterol. Insulin resistance and uric acid concentrations were beneficially affected by replacement of fructose with glucose. Our findings are limited by the very low to moderate certainty of evidence. This review was registered at www.crd.york.ac.uk/prospero as CRD42018080297.
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Design and Validation of a Diet Rich in Slowly Digestible Starch for Type 2 Diabetic Patients for Significant Improvement in Glycemic Profile.
Goux, A, Breyton, AE, Meynier, A, Lambert-Porcheron, S, Sothier, M, Van Den Berghe, L, Brack, O, Normand, S, Disse, E, Laville, M, et al
Nutrients. 2020;(8)
Abstract
This study aimed at designing a-diet high in slowly digestible starch (SDS) by carefully selecting high-SDS starchy products and to validate its implementation, acceptance, and impact on the postprandial glycemic response in patients with type 2 diabetes (T2D). Starchy products were screened and classified as being either high (high-SDS) or low (low-SDS) in SDS (in vitro SDS method). A randomized controlled cross-over pilot study was performed: Eight patients with T2D consumed randomly a high-SDS or a low-SDS diet for one week each, while their glycemic profile was monitored for 6 days. Based on 250 food product SDS analyses and dietary recommendations for patients with T2D, the high-SDS and low-SDS diets were designed. The high-SDS diet significantly increased SDS intake and the SDS/carbohydrates proportion compared to the low-SDS diet (61.6 vs. 11.6 g/day and 30% vs. 6%; p < 0.0001, respectively). Increasing the SDS/carbohydrate proportion to 50% of the meal was significantly correlated with a 12% decrease in tAUC0-120 min and a 14% decrease in the glycemic peak value (p < 0.001 for both). A high-SDS diet can be easily designed by carefully selecting commercial starchy products and providing relevant recommendations for T2D to improve their glycemic profile.
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Resistant starch supplementation increases crypt cell proliferative state in the rectal mucosa of older healthy participants.
Malcomson, FC, Willis, ND, McCallum, I, Xie, L, Ouwehand, AC, Stowell, JD, Kelly, S, Bradburn, DM, Belshaw, NJ, Johnson, IT, et al
The British journal of nutrition. 2020;(4):374-385
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Abstract
There is strong evidence that foods containing dietary fibre protect against colorectal cancer, resulting at least in part from its anti-proliferative properties. This study aimed to investigate the effects of supplementation with two non-digestible carbohydrates, resistant starch (RS) and polydextrose (PD), on crypt cell proliferative state (CCPS) in the macroscopically normal rectal mucosa of healthy individuals. We also investigated relationships between expression of regulators of apoptosis and of the cell cycle on markers of CCPS. Seventy-five healthy participants were supplemented with RS and/or PD or placebo for 50 d in a 2 × 2 factorial design in a randomised, double-blind, placebo-controlled trial (the Dietary Intervention, Stem cells and Colorectal Cancer (DISC) Study). CCPS was assessed, and the expression of regulators of the cell cycle and of apoptosis was measured by quantitative PCR in rectal mucosal biopsies. SCFA concentrations were quantified in faecal samples collected pre- and post-intervention. Supplementation with RS increased the total number of mitotic cells within the crypt by 60 % (P = 0·001) compared with placebo. This effect was limited to older participants (aged ≥50 years). No other differences were observed for the treatments with PD or RS as compared with their respective controls. PD did not influence any of the measured variables. RS, however, increased cell proliferation in the crypts of the macroscopically-normal rectum of older adults. Our findings suggest that the effects of RS on CCPS are not only dose, type of RS and health status-specific but are also influenced by age.
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Pearl millet (Pennisetum glaucum) couscous breaks down faster than wheat couscous in the Human Gastric Simulator, though has slower starch hydrolysis.
Hayes, AMR, Swackhamer, C, Mennah-Govela, YA, Martinez, MM, Diatta, A, Bornhorst, GM, Hamaker, BR
Food & function. 2020;(1):111-122
Abstract
Consumption of traditional West African pearl millet (Pennisetum glaucum) couscous delayed gastric emptying in our recent human study compared to other starch-based foods (white rice, boiled potatoes, pasta). The objective of this study was to determine whether physical properties of pearl millet couscous affect particle breakdown and starch hydrolysis during simulated gastric digestion to understand the basis of the slow gastric emptying. Starch fine structure and viscosity were analyzed for initial millet and wheat couscous samples by high performance size-exclusion chromatography and the Rapid Visco Analyzer, respectively. Couscous samples were subjected to simulated gastric digestion using the Human Gastric Simulator (HGS), a dynamic model of human gastric digestion. Digesta was collected from the HGS at 30 min intervals over 180 min. Particle size and percent starch hydrolysis of couscous in the digesta were evaluated at each time point. The number of particles per gram of dry mass substantially increased over digestion time for millet couscous (p < 0.05), while changed little for the wheat couscous samples. Millet couscous showed lower starch hydrolysis per unit surface area of particles than wheat couscous (p < 0.05). Slower starch hydrolysis was associated with smaller (p < 0.05) amylose chain length for millet (839-963 DP) than for wheat (1225-1563 DP), which may enable enable a denser packing of millet starch molecules that impedes hydrolysis. We hypothesize that the slow gastric emptying rate of millet couscous observed in humans may be explained by its slow starch hydrolysis property that could activate the ileal brake system, independent of high particle breakdown rate in the stomach.