Effect of potato apical leaf curl disease on glycemic index and resistant starch of potato (Solanum tuberosum L.) tubers

Tomato leaf curl New Delhi virus-potato (ToLCNDV-potato) causes potato apical leaf curl disease which severely affects nutritional parameters such as carbohydrate, protein, and starch biosynthesis thereby altering glycemic index (GI) and resistant starch (RS) of potato. ToLCNDV-potato virus was inoculated on potato cultivars (Kufri Pukhraj [susceptible]; Kufri Bahar [resistant]) and various quality parameters of potato tuber were studied. There was a significant (P < 0.01) reduction in starch, amylose and resistant starch contents in the infected tubers. However, carbohydrate and amylopectin increased significantly (P < 0.01) which contributes to increased starch digestibility reflected with high GI and glycemic load values. Besides, ToLCNDV-potato infection leads to a significant increase in reducing sugar, sucrose, amino acid and protein in potato tubers. This is a first-ever study that highlights the impact of biotic stress on GI, RS and nutritional quality parameters of potato which is a matter of concern for consumers.

Study on structural characterization, physicochemical properties and digestive properties of euryale ferox resistant starch

At present, the raw materials for industrialized RS3 products are relatively simple and its purity is low. In addition, the correlation between structure and digestion characteristics of RS3 are rarely studied. In this study, euryale ferox, a kind of annual aquatic herb crop with high content of starch was used as a raw material to prepare RS3 by different methods, including autoclaving, enzymolysis-autoclaving and dual enzymolysis, respectively. The results showed that there were significant differences in the structure and physicochemical properties of the different euryale ferox resistant-enhanced and purified resistant starches (p < 0.05). Purified euryale ferox resistant starches belonged to B + V type crystal and had high thermal stability. After digestion, the structure and thermal properties of euryale ferox resistant-enhanced starches changed a lot. The digestion rate and estimated glycemic index (eGI) of the three kinds of purified euryale ferox RS3 were lower than 20% and 50%, respectively.

Talipot palm (Corypha umbraculifera L.) a nonconventional source of starch: Effect of citric acid on structural, rheological, thermal properties and in vitro digestibility

Starch from talipot palm trunk (Corypha umbraculifera L.), a new starch source, was treated with different citric acid concentrations (5%, 10%, 20%, and 40% of the dry weight of starch) to produce citrate starch. The influence of citric acid treatment on physicochemical, pasting, structural, thermal, rheological, and digestibility properties of talipot palm starch were studied. A new peak at 1728 cm^-1 was observed in the Fourier-transform infrared spectroscopy (FTIR) spectra of citric acid-treated starches, which confirmed the formation of an ester bond between starch molecule and citric acid. The crystalline pattern of talipot palm starch was unaffected by citric acid treatment, whereas the relative crystallinity decreased from 16.35% to 3.06%. The Rapid Visco Analysis of starch treated with citric acid did not show any characteristic peaks, however, the untreated starch showed a peak viscosity of 3646 cP. The gelatinization parameters decreased with an increase in the degree of substitution, and the enthalpy of gelatinization (ΔH_gel) decreased from 11.19 J/g to 6.37 J/g. The in-vitro digestibility of talipot palm starch was decreased by citric acid treatment, and that of the slowly digestible starch (SDS) and resistant starches (RS) increased significantly (p ≤ 0.05) from 31.71% to 39.43% and 37.55% to 53.38%, respectively.

Stability of fumonisin B1 and its bioaccessibility in extruded corn-based products

Fumonisins are a group of mycotoxins commonly associated with corn-based products and require innovative alternatives to control exposure to its toxicity. The objective of this research was to determine the effect of amylose and resistant starch on fumonisin B1 (FB₁) levels in extruded corn-based products as well as the toxin bioaccessibility upon digestion. Cornmeal contaminated with FB₁ (1.5 µg/g) was extruded alone or combined with high-amylose corn starch (20%, w/w). FB₁ was quantified both in the unextruded and extruded products by HPLC (high-performance liquid chromatography) fluorescence detector with pre-column derivatization. Samples were then subjected to an in vitro digestion model to evaluate the stability of the interaction between FB₁ and the corn matrix extruded. The addition of high-amylose corn starch further reduced the detection of FB₁ (74.9%), when compared with the effect of the extrusion alone (66.0%), confirming the binding of FB₁ with the macromolecules or resistant starch. The bound fumonisin was stable upon simulated gastric digestion, and the duodenal bioaccessibility of free FB₁ was lower than 35% when high-amylose corn starch ingredient was used in the product. Principal component analysis (PCA) showed that high-amylose corn starch and resistant starch content influenced the reduction of FB₁ and its duodenal bioaccessibility. This study for the first time shows that addition of high-amylose corn starch during extrusion is an innovative strategy to reduce FB₁ release under digestive conditions, therefore useful in mitigating the exposure to this mycotoxin.

Nutritional, physical and sensory characteristics of gluten-free biscuits incorporated with a novel resistant starch ingredient

Gluten-free (GF) biscuits were prepared by replacing part of a GF flour mix (GFM) with 0, 15, 30 and 45 g/100 g (total flour) with a novel resistant starch-rich ingredient obtained from annealed white sorghum starch (RSWS). The chemical composition, physical characteristics, in vitro starch digestion and sensory evaluation of biscuits were considered. The chemical composition of samples was influenced by the addition of the RSWS. The highest total dietary fibre and RS contents (p < 0.05) were measured in 45-RSWS biscuits. The starch hydrolysis index values decreased when the level of RSWS increased in the composite. With regard to quality parameters, the use of RSWS influenced the hardness of the biscuits, and the highest value obtained for 45-RSWS. Some of the selected sensory attributes, along with the overall acceptability score, were negatively influenced by the RSWS addition, even if all remained above the limit of acceptability. The use of RSWS in GF biscuit formulation can contribute towards the creation of food products likely having slowly digestible starch properties, and this can be achieved without drastically compromising on the quality and sensory attributes.

Morphology, crystalline structure and digestibility of debranched starch nanoparticles varying in average degree of polymerization and fabrication methods

The objective of this study is to investigate physicochemical characteristics and digestibility of starch nanoparticles (SNPs) fabricated from debranched cassava starch varying degree of polymerization (DP¯_n) using nanoprecipitation and microemulsion methods. The high DP¯_n starch (HDPS) with DP¯_n > 35 monomers, medium DP¯_n starch (MDPS) with 15 < DP¯_n < 30) and low DP¯_n starch (LDPS) with DP¯_n < 10 were used. The SNPs fabricated from the HDPS were well-dispersed and smaller size, whereas those prepared from the MDPS and LDPS had bigger size and more aggregation. The SNPs produced by the microemulsion method were larger and more aggregated than those by the nanoprecipitation method. All SNPs exhibited the V + B-type X-ray diffraction pattern with higher relative crystallinity and more ordered structure than native starch. The SNPs fabricated from the LDPS also had higher amount of RS with lower blood glucose response in mice than those from the MDPS and HDPS.

High-amylose corn in gluten-free pasta: Strategies to deliver nutritional benefits ensuring the overall quality

High-amylose corn alone or in combination (25% and 50%) with conventional corn was used to produce gluten-free pasta. Flour pre-gelatinization in a tank (process A) or on a conveyor belt (process B) were tested. Resistant starch (RS), soluble (SPAs) and cell-wall bound phenolic acids (CWBPAs) and antioxidant capacity were significantly higher in high-amylose corn pasta. Cooked pasta from process B showed a higher SPA concentration, likely due to the lower cooking loss. The structure of pasta prepared with process B was more homogeneous, whereas it was more compact in the case of process A, as shown by a lower starch susceptibility to α-amylase hydrolysis, higher beginning of gelatinization temperature and lower water absorption. 25% HA represents a good compromise between high RS (4.2%) and good cooking behavior. At higher HA levels, process B is more suitable to obtain pasta with a better cooking quality.

Preparation, structural characteristics and physiological property of resistant starch

Starch is of the most important carbohydrates in human diets for maintaining normal body's energy metabolisms. However, due to the increased number of chronic diseases worldwide, the further study of the starch property in the dietary formula becomes essential for revealing its association with preventing or intervening the occurrence of such diseases as diabetes, obesity, intestinal diseases and even cardiovascular diseases. Considering that different starches demonstrate different digestion property based on their individual structural characteristics, in particular, the existence of resistant starch (RS) attracts much more interests recently because of its being a major producer of short-chain fatty acids followed by gut microbial fermentation. Furthermore, the understanding of the interaction between RS and microbiota in the gut and its substantial influence on the regulation of diabetes, kidney, disease hypertension and others is still being under investigated. Therefore, this chapter summarized the fine structure of starch, resistant starch structural characteristics, formation and preparation of resistant starches and their corresponding physiological property.

Pearl millet grain as an emerging source of starch: A review on its structure, physicochemical properties, functionalization, and industrial applications

Pearl millet (Pennisetum glaucum (L.) R.Br.) is a sustainable and underutilized starch source, constituting up to 70 % starch in its grain. Pearl millet could be used as a cheaper source of starch as compared to other cereals for developing functional foods. This review is mainly focused on isolation methods, and chemical composition of the pearl millet starch (PMS). Techno-functional characteristics such as; gelatinization, pasting properties, solubility, swelling power, and digestibility to infer wider application of the PMS critically highlighted in the review. Native starches have limited functionalitiesfor food applications due to the instability in developed pastes and gels. A number of modifications (physical, mechanical and enzymatic) have been developed to increase the functionality and to obtain desired characteristics of PMS thus improving its utilization in food applications. Further, the utilization of native as well as modified PMS is also discussed comprehensively. In addition, a number of recommendations to further improve its functionality and increase its application are also discussed.

Triple null mutations in starch synthase SSIIa gene homoeologs lead to high amylose and resistant starch in hexaploid wheat

BACKGROUND

Lack of nutritionally appropriate foods is one of the leading causes of obesity in the US and worldwide. Wheat (Triticum aestivum) provides 20% of the calories consumed daily across the globe. The nutrients in the wheat grain come primarily from the starch composed of amylose and amylopectin. Resistant starch content, which is known to have significant human health benefits, can be increased by modifying starch synthesis pathways. Starch synthase enzyme SSIIa, also known as starch granule protein isoform-1 (SGP-1), is integral to the biosynthesis of the branched and readily digestible glucose polymer amylopectin. The goal of this work was to develop a triple null mutant genotype for SSIIa locus in the elite hard red winter wheat variety 'Jagger' and evaluate the effect of the knock-out mutations on resistant starch content in grains with respect to wild type.

RESULTS

Knock-out mutations in SSIIa in the three genomes of wheat variety 'Jagger' were identified using TILLING. Subsequently, these loss-of function mutations on A, B, and D genomes were combined by crossing to generate a triple knockout mutant genotype Jag-ssiia-∆ABD. The Jag-ssiia-∆ABD had an amylose content of 35.70% compared to 31.15% in Jagger, leading to ~ 118% increase in resistant starch in the Jag-ssiia-∆ABD genotype of Jagger wheat. The single individual genome mutations also had various effects on starch composition.

CONCLUSIONS

Our full null Jag-ssiia-∆ABD mutant showed a significant increase in RS without the shriveled grain phenotype seen in other ssiia knockouts in elite wheat cultivars. Moreover, this study shows the potential for developing nutritionally improved foods in a non-GM approach. Since all the mutants have been developed in an elite wheat cultivar, their adoption in production and supply will be feasible in future.

Impact of esterification with malic acid on the structural characteristics and in vitro digestibilities of different starches

This research focused on the structural characteristics of resistant starches (RSs) that were obtained from corn, potato, and sweet potato and esterified by L-malic acid. Further, the unique effect of the degree of substitution (DS) on the crystalline properties was studied. Different starches were allowed to react with 2 M malic acid (pH 1.5) for 12 h at 130 °C. The shapes of the granules and the Maltese-cross shapes of samples were maintained and visible under an optical microscope. The FT-IR spectrum displayed evident carbonyl peaks at 1740 cm^-1, and the onset temperature (T_o) and gelatinization enthalpy (∆H) gradually decreased as DS increased. The malic acid-treated starches exhibited an increased RS content compared to those of the control. The RS contents of potato, sweet potato, and corn, which were 65.5%, 70.0%, and 89.8% in the uncooked MT-samples, decreased to 57.3%, 63.8%, and 86.7% in the cooked MT-samples, respectively, and exhibited high heat stability; corn starch yielded the highest RS among them. The thermal and malic acid treatments resulted in the partial hydrolysis and rearrangement of the helix structure of crystalline area, which was affected by esterification. The result revealed that the RS content increased as that of DS escalated.

The effect of acute consumption of resistant starch on appetite in healthy adults; a systematic review and meta-analysis of the controlled clinical trials

BACKGROUND & AIMS

Although several clinical trials have assessed the effect of Resistant Starch (RS) supplementation on appetite, the results have been inconsistent. Therefore, this study aimed to assess the effect of RS on the healthy adults' rating of appetite.

MATERIALS AND METHODS

To this end, Pubmed, CENTRAL, Web of science, Scopus, Medline, and Proquest were systematically searched to find the relevant randomized, and placebo-controlled human trials up to June 2019. As a result, the area under curve (AUC) and standard deviations of the participants' rating appetite were extracted from four eligible studies.

RESULTS

Meta-analysis showed a lower appetite in RS group compared to the controls (weighted mean difference [WMD] = -1.375 mm min, 95% confidence interval [95%CI]: -1.673, -1.076). Since high heterogeneity was observed among the included studies (I² = 94.5%, P < 0.001), subgroup analysis was carried out by RS dose, RS type, duration of supplementation, and time of AUC measuring. In studies that used RS dose of ≥25 gr, heterogeneity disappeared (P = 0.560, I² = 0%). In such studies, a significant reduction was observed in rating of appetite (WMD = -4.513 mm min, 95%CI: -5.270, -3.755; P < 0.001) than studies with RS dose of <25 gr (WMD = -0.799 mm min, 95%CI: -1.123,-0.474; P < 0.001). Additionally, subgroup analysis based on the type of RS showed a significant decrease of appetite in studies that used RS2 (WMD = -4.808 mm min, 95%CI: -5.834, -3.782; P < 0.001) than RS1 (WMD = -0.128 mm min, 95%CI: -0.457, 0.202; P = 0.448).

CONCLUSIONS

To decrease the rate of appetite more effectively, we suggest other researchers to identify RS dose and type.

Generation and Starch Characterization of Non-Transgenic BEI and BEIIb Double Mutant Rice (Oryza sativa) with Ultra-High Level of Resistant Starch

BACKGROUND

Cereals high in resistant starch (RS) are gaining popularity, as their intake is thought to help manage diabetes and prediabetes. Number of patients suffering from diabetes is also increasing in Asian countries where people consume rice as a staple food, hence generation of practically growable high RS rice line has been anticipated. It is known that suppression of starch branching enzyme (BE) IIb increases RS content in cereals. To further increase RS content and for more practical use, we generated a non-transgenic be1 be2b double mutant rice (Oryza sativa) line, which completely lacked both proteins, by crossing a be1 mutant with a be2b mutant.

RESULTS

The be1 be2b mutant showed a decrease in intermediate amylopectin chains and an increase in long amylopectin chains compared with be2b. The amylose content of be1 be2b mutant (51.7%) was the highest among all pre-existing non-transgenic rice lines. To understand the effects of chewing cooked rice and cooking rice flour on RS content, RS content of mashed and un-mashed cooked rice as well as raw and gelatinized rice flour were measured using be1 be2b and its parent mutant lines. The RS contents of mashed cooked rice and raw rice flour of be1 be2b mutant (28.4% and 35.1%, respectively) were 3-fold higher than those of be2b mutant. Gel-filtration analyses of starch treated with digestive enzymes showed that the RS in be1 be2b mutant was composed of the degradation products of amylose and long amylopectin chains. Seed weight of be1 be2b mutant was approximately 60% of the wild type and rather heavier than that of be2b mutant.

CONCLUSIONS

The endosperm starch in be1 be2b double mutant rice were enriched with long amylopectin chains. This led to a great increase in RS content in cooked rice grains and rice flour in be1 be2b compared with be2b single mutant. be1 be2b generated in this study must serve as a good material for an ultra-high RS rice cultivar.

Resistant starch, microbiome, and precision modulation

Resistant starch, microbiome, and precision modulation. Mounting evidence has positioned the gut microbiome as a nexus of health. Modulating its phylogenetic composition and function has become an attractive therapeutic prospect. Resistant starches (granular amylase-resistant α-glycans) are available as physicochemically and morphologically distinguishable products. Attempts to leverage resistant starch as microbiome-modifying interventions in clinical studies have yielded remarkable inter-individual variation. Consequently, their utility as a potential therapy likely depends predominantly on the selected resistant starch and the subject's baseline microbiome. The purpose of this review is to detail i) the heterogeneity of resistant starches, ii) how resistant starch is sequentially degraded and fermented by specialized gut microbes, and iii) how resistant starch interventions yield variable effects on the gut microbiome.

Resistant starch intake alleviates collagen-induced arthritis in mice by modulating gut microbiota and promoting concomitant propionate production

Gut dysbiosis precedes clinic symptoms in rheumatoid arthritis (RA) and has been implicated in the initiation and persistence of RA. The early treatment of RA is critical to better clinical outcome especially for joint destruction. Although dietary interventions have been reported to be beneficial for RA patients, it is unclear to whether diet-induced gut microbiome changes can be a preventive strategy to RA development. Here, we investigated the effect of a high fiber diet (HFD) rich with resistant starch (RS) on collagen-induced arthritis (CIA) and gut microbial composition in mice. RS-HFD significantly reduced arthritis severity and bone erosion in CIA mice. The therapeutic effects of RS-HFD were correlated with splenic regulatory T cell (Treg) expansion and serum interleukin-10 (IL-10) increase. The increased abundance of Lactobacillus and Lachnoclostridium genera concomitant with CIA were eliminated in CIA mice fed the RS-HFD diet. Notably, RS-HFD also led to a predominance of Bacteroidetes, and increased abundances of Lachnospiraceae_NK4A136_group and Bacteroidales_S24-7_group genera in CIA mice. Accompanied with the gut microbiome changes, serum levels of the short-chain fatty acid (SCFA) acetate, propionate and isobutyrate detected by GC-TOFMS were also increased in CIA mice fed RS-HFD. While, addition of β-acids from hops extract to the drinking water of mice fed RS-HFD significantly decreased serum propionate and completely eliminated RS-HFD-induced disease improvement, Treg cell increase and IL-10 production in CIA mice. Moreover, exogenous propionate added to drinking water replicated the protective role of RS-HFD in CIA including reduced bone damage. The direct effect of propionate on T cells in vitro was further explored as at least one mechanistic explanation for the dietary effects of microbial metabolites on immune regulation in experimental RA. Taken together, RS-HFD significantly reduced CIA and bone damage and altered gut microbial composition with concomitant increase in circulating propionate, indicating that RS-rich diet might be a promising therapy especially in the early stage of RA.

A novel cold-active type I pullulanase from a hot-spring metagenome for effective debranching and production of resistant starch

Pullulanase is a potent enzyme for starch debranching. In this study, a novel type I pullulanase (Pul_M) was identified from the metagenome of a thermal aquatic habitat that exhibits optimal activity of debranching at 40 °C temperature and pH 6.0 to 7.0. More than 50% enzymatic activity was detected at the low temperature of 4 °C, determining it a cold-active type I pullulanase. It was able to efficiently catalyze the hydrolysis of α-1,6-glycosidic linkages in pullulan, with a specific activity of 177 U mg^-1. The results determined Pul_M to be a potential starch debranching biocatalyst, causing a significant increase of about 80% in the apparent amylose content of potato starch. Retrogradation of the debranched starch resulted in the formation of resistant starch 3. The yield of resistant starch was estimated to be about 45%. The resistant starch exhibited higher crystallinity, enhanced heat-stability, and resistance to α-amylase digestion, as compared to native starch.

Increasing levels of Parasutterella in the gut microbiome correlate with improving low-density lipoprotein levels in healthy adults consuming resistant potato starch during a randomised trial

BACKGROUND

Prebiotics, defined as a substrate that is selectively utilized by host microorganisms conferring a health benefit, present a potential option to optimize gut microbiome health. Elucidating the relationship between specific intestinal bacteria, prebiotic intake, and the health of the host remains a primary microbiome research goal.

OBJECTIVE

To assess the correlations between gut microbiota, serum health parameters, and prebiotic consumption in healthy adults.

METHODS

We performed ad hoc exploratory analysis of changes in abundance of genera in the gut microbiome of 75 participants from a randomized, placebo-controlled clinical trial that evaluated the effects of resistant potato starch (RPS; MSPrebiotic®, N = 38) intervention versus a fully digestible placebo (N = 37) for which primary and secondary outcomes have previously been published. Pearson correlation analysis was used to identify relationships between health parameters (ie. blood glucose and lipids) and populations of gut bacteria.

RESULTS

Abundance of Parasutterella (phylum Proteobacteria) tended to increase in the gut microbiome of individuals consuming RPS and those increases in Parasutterella were correlated with reductions in low-density lipoprotein (LDL) levels in participants consuming RPS but not placebo. Segregating RPS-consuming individuals whose LDL levels decreased (ie "Responders") from those who did not (ie. "Non-Responders") revealed that LDL Responders had significantly higher levels of Parasutterella both at baseline and after 12 weeks of consuming RPS.

CONCLUSION

Our analyses suggest that RPS may help improve LDL levels depending upon the levels of Parasutterella in an individual's gut microbiome.

TRIAL REGISTRATION

This study protocol was reviewed and approved by Health Canada (Submission #188517; "Notice of Authorization" dated 06/05/13) and registered as NCT01977183 (10/11/13) listed on NIH website: ClinicalTrials.gov. Data generated in this study have been submitted to NCBI ( http://www.ncbi.nlm.nih.gov/bioproject/381931 ).

FUNDING

MSP Starch Products Inc.

Structural, functional and digestibility characteristics of sorghum and corn starch extrudates (RS3) as affected by cold storage time

The aim of the study was to compare the properties of resistant starch (RS₃) formed during extrusion of corn and sorghum starches. The extrudates were stored for 7 and 14 days at 4 °C to allow for molecular rearrangement i.e. retrogradation. The extruded starches were analyzed for enzymatic digestibility, long range (X-ray diffraction, XRD) and short range (FTIR) molecular order, thermal characteristics (DSC) and rheological properties as affected by temperature. The highest RS (70.64%) was obtained for sorghum extrudate (ES₁₄) as compared to corn extrudate (EC₁₄) (64.90%), on 14th day of storage. The increase in RS correlates with the increase in percent crystallinity (%Xc), too. The (ES₁₄) reported the highest %Xc among all extrudates i.e.37.83. The XRD results showed an additional peak at 13° and 20°, reflecting the formation of V-type pattern in all samples. The FTIR spectroscopy also exhibited increase in the ratio of 1047 cm^-1/1151 cm^-1 and 1047 cm^-1/1022 cm^-1. The extruded starch showed significantly higher thermal stability and lower cold paste viscosity. The significant (p ≤ 0.05) decrease in the glycemic index was obtained as the storage time increased. The (ES₁₄) exhibited glycemic index equal to (EC₁₄) i.e.55.53 and 52.53, respectively; thereby making it a suitable substitute of corn starch.

Physicochemical and prebiotic properties of resistant starch from Musa sapientum Linn., ABB group, cv. Kluai Namwa Luang

Resistant starch (RS), a current health trend, can be obtained from various natural sources. Musa sapientum Linn., ABB group, cv. Kluai Namwa Luang is a good source of RS. This is the first study to investigate the physicochemical properties, RS contents, and prebiotic properties of unpeeled raw banana powder (URB), peeled raw banana powder (PRB), and banana starch (BS) from Kluai Namwa Luang. Their physicochemical properties were characterized by scanning electron microscope, differential scanning calorimeter, and X-ray diffractometer. The RS contents were determined using the Megazyme Resistant Starch Assay Kit. The prebiotic properties are reported as a prebiotic index (PI). The particle morphology of URB, PRB, and BS granules showed a smooth surface with irregular size and shape. Their gelatinization temperatures were 74-78 °C. All samples exhibited typical B-type diffraction patterns. URB contained the highest dietary fiber (9.7 ± 0.2 g per 100 g of dried sample), whereas BS contained the highest RS content (74.1 ± 0.1 g per 100 g of dried sample). Both URB and BS possessed excellent probiotic growth promotion, prebiotic properties with PI values comparable to the commercial inulin, and were highly resistant to digestive enzymes. Therefore, BS from Kluai Namwa Luang is suggested as functional nutrient in health promotion products.

A functional ecological network based on metaproteomics responses of individual gut microbiomes to resistant starches

Resistant starches (RS) are dietary compounds processed by the gut microbiota into metabolites, such as butyrate, that are beneficial to the host. The production of butyrate by the microbiome appears to be affected by the plant source and type of RS as well as the individual's microbiota. In this study, we used in vitro culture and metaproteomic methods to explore individual microbiome's functional responses to RS2 (enzymatically-resistant starch), RS3 (retrograded starch) and RS4 (chemically-modified starch). Results showed that RS2 and RS3 significantly altered the protein expressions in the individual gut microbiomes, while RS4 did not result in significant protein changes. Significantly elevated protein groups were enriched in carbohydrate metabolism and transport functions of families Eubacteriaceae, Lachnospiraceae and Ruminococcaceae. In addition, Bifidobacteriaceae was significantly increased in response to RS3. We also observed taxon-specific enrichments of starch metabolism and pentose phosphate pathways corresponding to this family. Functions related to starch utilization, ABC transporters and pyruvate metabolism pathways were consistently increased in the individual microbiomes in response to RS2 and RS3. Given that these taxon-specific responses depended on the type of carbohydrate sources, we constructed a functional ecological network to gain a system-level insight of functional organization. Our results suggest that while some microbes tend to be functionally independent, there are subsets of microbes that are functionally co-regulated by environmental changes, potentially by alterations of trophic interactions.

The effects of 16-weeks of prebiotic supplementation and aerobic exercise training on inflammatory markers, oxidative stress, uremic toxins, and the microbiota in pre-dialysis kidney patients: a randomized controlled trial-protocol paper

BACKGROUND

Chronic kidney disease (CKD) is characterized by dysbiosis, elevated levels of uremic toxins, systemic inflammation, and increased markers of oxidative stress. These factors lead to an increased risk of cardiovascular disease (CVD) which is common among CKD patients. Supplementation with high amylose maize resistant starch type 2 (RS-2) can change the composition of the gut microbiota, and reduce markers of inflammation and oxidative stress in patients with end-stage renal disease. However, the impact of RS-2 supplementation has not been extensively studied in CKD patients not on dialysis. Aerobic exercise training lowers certain markers of inflammation in CKD patients. Whether combining aerobic training along with RS-2 supplementation has an additive effect on the aforementioned biomarkers in predialysis CKD patients has not been previously investigated.

METHODS

The study is being conducted as a 16-week, double-blind, placebo controlled, parallel arm, randomized controlled trial. Sixty stage 3-4 CKD patients (ages of 30-75 years) are being randomized to one of four groups: RS-2 & usual care, RS-2 & aerobic exercise, placebo (cornstarch) & usual care and placebo & exercise. Patients attend four testing sessions: Two baseline (BL) sessions with follow up visits 8 (wk8) and 16 weeks (wk16) later. Fasting blood samples, resting brachial and central blood pressures, and arterial stiffness are collected at BL, wk8 and wk16. A stool sample is collected for analysis of microbial composition and peak oxygen uptake is assessed at BL and wk16. Blood samples will be assayed for p-cresyl sulphate and indoxyl sulphate, c-reactive protein, tumor necrosis factor α, interleukin 6, interleukin 10, monocyte chemoattractant protein 1, malondialdehyde, 8-isoprostanes F2a, endothelin-1 and nitrate/nitrite. Following BL, subjects are randomized to their group. Individuals randomized to conditions involving exercise will attend three supervised moderate intensity (55-65% peak oxygen uptake) aerobic training sessions (treadmills, bikes or elliptical machine) per week for 16 weeks.

DISCUSSION

This study has the potential to yield information about the effect of RS-2 supplementation on key biomarkers believed to impact upon the development of CVD in patients with CKD. We are examining whether there is an additive effect of exercise training and RS-2 supplementation on these key variables.

TRIAL REGISTRATION

Clinicaltrials.gov Trial registration# NCT03689569 . 9/28/2018, retrospectively registered.

The effects of resistant starches on inflammatory bowel disease in preclinical and clinical settings: a systematic review and meta-analysis

Background

Inflammatory bowel disease (IBD) is a debilitating chronic disease with limited treatment options. Resistant starches may represent a novel treatment for IBD. However, its efficacy and safety remain unclear. Our objective was to perform a systematic review to summarize the preclinical and clinical effects of resistant starch, which may help guide future studies.

Methods

Medline, EMBASE, and the Cochrane Central Register were searched. Included studies investigated the use of resistant starch therapy in in vivo animal models of IBD or human patients with IBD. Articles were screened, and data extracted, independently and in duplicate. The primary outcomes were clinical remission (clinical) and bowel mucosal damage (preclinical).

Results

21 preclinical (n = 989 animals) and seven clinical (n = 164 patients) studies met eligibility. Preclinically, resistant starch was associated with a significant reduction in bowel mucosal damage compared to placebo (standardized mean difference − 1.83, 95% CI − 2.45 to − 1.20). Clinically, five studies reported data on clinical remission but clinical and methodological heterogeneity precluded pooling. In all five, a positive effect was seen in patients who consumed resistant starch supplemented diets. The majority of studies in both the preclinical and clinical settings were at a high or unclear risk of bias due to poor methodological reporting.

Conclusions

Our review demonstrates that resistant starch is associated with reduced histology damage in animal studies, and improvements in clinical remission in IBD patients. These results need to be tempered by the risk of bias of included studies. Rigorously designed preclinical and clinical studies are warranted.

Trial registration

The review protocols were registered on PROSPERO (preclinical: CRD42019130896; clinical: CRD42019129513).

Biochemical and functional attributes of raw and boiled potato flesh and peel powders for suitability in food applications

Four different potato cultivars, namely, Kufri Chipsona 1 and Kufri Frysona (processing purpose), Kufri Jyoti and Kufri Bahar (table purpose) were converted into flesh and peel powder (raw and after boiling) and studied for their respective biochemical and functional attributes to get an idea of possible dynamics of their utilization in different food formulation as bioadditives. The 16 variants of powder obtained retained less than 10% moisture content and demonstrated 'very good' to 'fair' flowability. Peel powders recorded a higher total mineral, fiber, phenolic contents and total antioxidant activity than the flesh powders which were significantly affected by boiling. Among raw and boiled flesh powders, highest reducing and total sugars were recorded for Kufri Bahar while least was observed in Kufri Chipsona 1. Colour coordinate showed that boiling imparts brightness to flesh powder while peel powder got darkened. Boiling of the tubers resulted in an increase in the resistant starch (~ 29% maximum) and flavour (~ 180% maximum) component. Peel exhibited a total glycoalkaloid content in the range of 0.75 (Kufri Frysona) to 1.7 mg/100 g (Kufri Bahar) that is well within the acceptable limits. Rheological study of the flesh powders revealed a reduction of about 11-18 °C in pasting temperature and about 87-90% in peak viscosity, setback, breakdown value and final viscosity upon boiling. This study revealed that the traditional processing method such as boiling can significantly modify the techno-functional characteristics of potato flesh and peel powders which can further govern their end use in various food formulations.

Effect of resistant starch type 2 on inflammatory mediators: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Inflammation is the main cause in the development of chronic diseases. The enhancement of pro-inflammatory factors, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hs-CRP) is the main risk factor in chronic diseases. Resistant starch type 2 (RS2) is non-gelatinized granules which their enzymatic hydrolysis is very low. RS2 might be able to reduce inflammatory mediators, therefore; our aim for this study was indicating RS2 effects on inflammatory mediators such as IL-6, TNF-a, and CRP among healthy and unhealthy subjects.

METHODS

Articles which assessed RS2 effect on IL-6, TNF-α, and hs-CRP were found by advanced search methods. Electronic databases including Google scholar, ISI web of science, SCOPUS, and PubMed, were searched up to October 2019. Treatment effect was the mean difference between changes in serum levels of inflammatory biomarkers in each arm of the clinical trials. To pool the effect of resistant starch on inflammatory biomarkers, we used random effects model.

RESULTS

We included eight articles in systematic review and meta-analysis. The overall effect illustrated no significant change in serum levels of hs-CRP, IL-6, and TNF-α in intervention group compared with the control group (WMD: -7.18 pg/mL, 95% CI: -27.80, 13.45; P = 0.495, I² = 100.0%, WMD: -0.003 pg/mL, 95% CI: -0.07, 0.06; P = 0.919, I² = 98.1%, WMD: -0.003 pg/mL, 95% CI: -0.004, -0.001; P < 0.0001, I² = 98.0% respectively).

CONCLUSION

In conclusion, we found that RS2 could not reduce inflammatory mediators, but we still need more RCTs with longer intervention duration, higher dose, and studies in different countries.

Potential of Musa sapientum Linn. for digestive function promotion by supporting Lactobacillus sp

Lactobacillus is a beneficial bacteria that could inhibit pathogenic potential of other microorganisms. This is the first study to develop a potential tablet from Musa sapientum Linn. (locally known as Kluai Namwa) using the direct compression method to support Lactobacillus sp. We compared the amount of resistant starch and prebiotic properties of the dry powder from unpeeled raw fruit, peeled raw fruit, and starch from M. sapientum. These dry powders were formulated into tablets using the direct compression method and evaluated for their prebiotic index compared to their native powder. Resistant starch, which possessed the highest prebiotic index, generated a tablet that possessed remarkable in vitro prebiotic properties. All tablets met the requirement of the United States Pharmacopeia. Therefore, resistant starch tablets from M. sapientum are suggested for use as a health promotion product.