High-amylose Maize Starch Research Articles

The effect of amylose on kernel phenotypic characteristics, starch-related gene expression and amylose inheritance in naturally mutated high-amylose maize

High-amylose maize starch has great potential for widespread industrial use due to its ability to form strong gels and film and in the food processing field, thus serving as a resistant starch source. However, there is still a substantial shortage of high-amylose maize due to the limitation of natural germplasm resources, although the well-known amylose extender (ae) gene mutants have been found to produce high-amylose maize lines since 1948. In this context, high-amylose maize lines (13 inbreds and 18 hybrids) originating from a natural amylose mutant in our testing field were utilized to study the correlation between amylose content (AC) and phenotypic traits (kernel morphology and endosperm glossiness), grain filling characteristics, gene expression, and amylose inheritance. Our results showed that AC was negatively correlated with total starch content but was not correlated with grain phenotypes, such as kernel fullness, kernel morphology and endosperm glossiness. Maize lines with higher amylose had a greater grain filling rate than that of the control (B73) during the first 20 days after pollination (DAP). Both starch debranching enzyme (DBE) groups and starch branching enzyme IIb (SBEIIb) groups showed a greater abundance in the control (B73) than in the high-amylose maize lines. Male parents directly predicted AC of F1, which was moderately positively correlated with the F2 generation.

In vitro digestibility of different types of resistant starches under high-temperature cooking conditions

Resistant starch (RS) is commercially available as an important category of functional food ingredients. Starch tends to lose the enzymatic resistance upon heat treatment; however, there is a dearth of knowledge on how thermal treatment, especially high-temperature processing, influences the digestibility of different types of RS. In this study, two high-amylose maize starches (HA50 and HA70; RS2), Novelose 330 (RS3), and two cross-linked phosphorylated wheat starch (Fibersym and FiberRite; RS4) were cooked using Rapid Visco Analyzer 4800 at 95, 120 and 140 °C, and their in vitro digestibility was determined after 0.5 and 2.0-h storage at room temperature. The cooking step substantially reduced the enzymatic resistance of RS2, with the lowest RS contents being determined at 120 °C cooking upon 0.5-h storage. Generally, 2.0-h storage enhanced the enzymatic resistance of RS2 cooked at 120 and 140 °C, resulting from stronger re-association and retrogradation between starch molecules during the storage. In contrast, cooking over 95–140 °C did not considerably alter the RS contents of Novelose 330 and FiberRite, indicating their greater stability against high-temperature processing. Moreover, 2.0-h storage did not appear to further increase the enzymatic resistance of cooked RS3 and RS4. The relationships between the digestibility of cooked RS2-4 and their thermal, pasting and gelling properties were thoroughly discussed to elucidate the mechanisms contributing to the enzymatic resistance of the different types of RS under the examined conditions. The fundamental knowledge acquired from this work will be meaningful for the development and utilization of RS ingredients in food products processed under high-temperature conditions.

Consumption of an Oil Palm Fruit Extract Promotes Large Bowel Health in Rats

Oil palm fruit is widely used for edible oils, but the health benefits of other components are relatively unknown. We examined if consuming a polyphenol-rich extract of the fruit, from a vegetation by-product of oil processing, which also contains fibre, has gastro-intestinal benefits in rats on a Western-type diet (WD). The oil palm preparation (OPP) was added to food (OPP-F) or drinking water (OPP-D) to provide 50 mg of gallic acid equivalents (GAE)/d and compared to effects of high amylose maize starch (HAMS; 30%) in the diet or green tea extract (GT; 50 mg GAE/d) in drinking water over 4 wk. OPP treatments induced some significant effects (P < 0.05) compared to WD. OPP-D increased caecal digesta mass, caecal digesta concentrations of total SCFA, acetate and propionate (OPP-F increased caecal butyrate concentration), the numbers of mucus-producing goblet cells per colonic crypt, and caecal digesta abundance of some bacteria which may provide benefit to the host (Faecalibacterium prausnitzii, Akkermansia muciniphila and Ruminococcus gnavus). HAMS induced similar effects but with greater potency and had a broader impact on microbe populations, whereas GT had minimal impacts. These results suggest dietary OPP may benefit the large bowel.

The Physicochemical Characterization of Unconventional Starches and Flours Used in Asia.

Starches and flours used commonly in Asia (tapioca, sweet potato, sago, water chestnut, and high amylose maize starch, red rice and kithul flour) were characterized in terms of their chemical composition, morphological, functional, pasting, thermal, gelling and in vitro digestibility properties. It was observed that the differences in their chemical composition and structure influenced their properties. High amylose maize was the most stable, thus it required the highest gelatinization temperature which was observed in both the differential scanning calorimetry (DSC) and pasting profiles. Kithul flour had a significantly lower rate of digestion (p < 0.05) than the other samples (except for high amylose maize starch). Unlike high amylose maize starch, it had a gelatinization temperature that could be achieved during cooking, and had good gelling properties.

Effects of Ligand Concentration on the Thermal Properties, Structure, and Digestibility of Maize Starch Inclusion Complexes with Ascorbyl Palmitate

AbstractThe alkaline method is used to form the complex between starch and ascorbyl palmitate (AP) in this study. Normal maize starch (NMS) and high amylose maize starch (HAMS) are screened to investigate the effects of AP concentrations (0%, 2.5%, 5.0%, 10.0%, 20.0%) on the properties of complexes at 60 °C. HAMS can bind more AP than NMS because of more amylose content. Comparing the endothermic peaks in DSC analysis, 5% and 10% AP levels are sufficient to interact with NMS and HAMS, respectively. The disappeared or weakened AP characteristic absorption peaks in FTIR spectra prove the formation of V‐amylose structure. The XRD analyses reveal that the inclusion complexes are formed with AP with six glucose units per turn due to the steric hindrance of AP, and the self‐aggregation of AP in the complexes is also detected. The self‐aggregation of AP do not affect the indigested ordered helical chain segments of starch in in vitro digestion. The 5% and 10% AP levels are enough to decrease the rate and extent of starch digestion in NMS and HAMS complexes, respectively. The formation of starch‐AP inclusion complexes also appear to enhance the stability of AP against light, heat, and oxidation.

Fabrication and characterization of resistant starch stabilized Pickering emulsions

This study aims to understand the physicochemical properties of a type of resistant starch prepared through complexing high-amylose maize starch with fatty acid (lauric acid), and evaluate its capacity to form Pickering emulsions. During the preparation process, the mode of adding lauric acid and the moisture content of swelled starch (10%–50%) had a major influence on the physicochemical properties, including crystallinity, amphophilic, thermal and digestion properties, of starch/lauric acid complexes. The resulting resistant starches exhibited large differences regarding their emulsification ability during the formation of Pickering emulsions. The emulsification capacity of the starch/lauric acid complexes was positively related to their lipid contents, which impacted their hydrophobicity. The resulting Pickering emulsions exhibited good stability against different ionic strengths (100–400 mM), pH conditions (3–9) and heat treatments. The starch/lauric acid complexes stabilized Pickering emulsions have a practical potential as a new food formulation for encapsulation of lipophilic ingredients in food and pharmaceutical products.

Modification of resistant starch nanoparticles using high-pressure homogenization treatment

High amylose (HA) maize starch, rich in amylose (more than 55%), belongs to the category of resistant starch type 2 (RS2), and therefore has a specific structure resistant to digestion. The purpose of this study was to modify HA maize starch, reducing its particle size. A mechanical treatment was used, applying high-pressure homogenization (HPH) at different pressure conditions 140, 200 and 250 MPa and treatment cycles, ranging from 1 to 4. The impact of HPH on starch structure, including size, morphology and crystallinity as well as on the amylose content was investigated. The granule particle size was measured by Dynamic Light Scattering (DLS), their morphology using Scanning Electron Microscopy (SEM) and the degree of crystallinity by X-ray diffraction (XRD). According to the results the smallest particle size, 540 nm, was achieved after 4 cycles of homogenization at 250 MPa. It was found that the pressure applied was more significant to reduce granules’ size than the time of treatment. Αt intense pressure the granules structure has changed as pores, deep slots and aggregates were observed. The amylopectin structure was destroyed resulting in an increase in amylose:amylopectin ratio. However, size reduction was not accompanied by any structure conversion and HA maize starch remained a B-type starch. According to the information found a further understanding of the effect of HPH on modifying HA starch was achieved. Physically modified RS could result to different food applications.

Feed intake patterns nor growth rates of pigs are affected by dietary resistant starch, despite marked differences in digestion

Current feed evaluation systems often assume that fermented starch (i.e. resistant starch (RS)) yields less energy than digested starch. However, growth rates of pigs fed low and high RS diets are often the same when feed is available ad libitum. This may be explained by its effect on digestive processes changing feeding behavior, and consequently energy utilization. This study aims to investigate the effect of RS on nutrient digestion and digesta passage rate in pigs, in combination with its effect on feeding behavior and growth performance under ad libitum conditions. In experiment 1, 20 male pigs (40 ± 2.82 kg) were fed diets containing either 50% waxy maize starch (low in RS (LRS)) or high-amylose maize starch (high in RS (HRS)), and soluble and insoluble indigestible markers. After 14 days of adaptation to the diets, pigs were fed hourly to reach steady state (6 h), dissected, and digesta were collected from eight segments. From the collected samples, nutrient digestion and passage rate of the solid and liquid digesta fraction were determined. In experiment 2, 288 pigs (80 ± 0.48 kg; sex ratio per pen 1 : 1; boar : gilt) were housed in groups of 6. Pigs were ad libitum-fed one of the experimental diets, and slaughtered at approximately 115 kg. Feed intake, growth and carcass parameters were measured. Ileal starch digestibility was greater for LRS-fed than for HRS-fed pigs (98.0% v. 74.0%; P < 0.001), where the additional undigested starch in HRS-fed pigs was fermented in the large intestine. No effects of RS on digesta passage rate of the solid or liquid digesta fraction and on feeding behavior were observed. Growth rate and feed intake did not differ between diets, whereas feed efficiency of HRS-fed pigs was 1%-unit higher than that of LRS-fed pigs (P = 0.041). The efficiency of feed used for carcass gain did not differ between diets indicating that the difference in feed efficiency was determined by the non-carcass fraction. Despite a 30% greater RS intake (of total starch) with HRS than with LRS, carcass gain and feed efficiency used for carcass gain were unaffected. RS did not affect digesta passage rate nor feeding behavior suggesting that the difference in energy intake between fermented and digested starch is compensated for post-absorptively. Our results indicate that the net energy value of fermented starch currently used in pig feed evaluation systems is underestimated and should be reconsidered.

In vitro evaluation of fermentation characteristics of type 3 resistant starch

Four different resistant starch (RS) type 3 (RS3; retrograded starch) and a RS type 2 (RS2; native high amylose maize starch) were in vitro digested and fermented by faecal inoculum. Total and individual short chain fatty acid (SCFA) production and associated kinetic parameters were assessed up to 20 h of in vitro fermentation. Total SCFA production was different (p < 0.05) among RS-rich ingredients, ranging from 7.43 to 8.72 mmol/g dry starch incubated. Differences (p < 0.05) were recorded for propionate and butyrate productions. Different (p < 0.05) half-time of total SCFA fermentation (T1/2), maximum rate of production (Rmax) and the time of occurrence (Tmax) values were measured among RS-rich ingredients, ranging from 3.3 to 5.6 h, from 1.06 to 1.85 mmol/g dry starch incubated per hour and from 2.6 to 4.9 h, respectively. Similar trends were measured considering the fermentative kinetics of individual SCFA. Present preliminary in vitro findings indicated that quantitative and qualitative production of SCFA, and inherent fermentation kinetics, were influenced by the type of RS. These findings are based on an in vitro approach, thus requiring in vivo trials.

Inhibition of starch digestion by gallic acid and alkyl gallates

As phenolic compounds, alkyl gallates may inhibit the activity of digestive enzymes for starch. Furthermore, their alkyl chains may facilitate starch inclusion complexation and results in an increased resistant starch (RS) content or slowly digestible starch (SDS) content, which may further retard starch digestion. The significance of such inhibition is that the rate of starch hydrolysis into glucose is reduced, thereby preventing hyperglycemia and related metabolic diseases. This study examined the inhibitory effects on in vitro enzymatic digestion of starch by gallic acid and five alkyl gallates of varying alkyl chain lengths, i.e., butyl gallate, octyl gallate, dodecyl gallate, hexadecyl gallate, and octadecyl gallate. Raw and cooked potato starch (PS) and high-amylose maize starch (HAMS) were tested. For both types of raw starch, gallic acid and all the alkyl gallates significantly (p < 0.05) increased RS content except for octadecyl gallate. In the case of cooked starch, the RS contents were markedly decreased (p < 0.05) as compared to those in raw starch, because gelatinization caused an overall greater susceptibility to enzymatic digestion. The reduction in RS content was less in cooked HAMS than that in cooked PS, due to a higher gelatinization temperature range of HAMS. The aforementioned effect of gallates on RS content was also found for cooked PS, while cooked HAMS experienced increased RS only with gallic acid and butyl gallate. Overall, for the digestion of both starches, regardless of raw or cooked, gallic acid and alkyl gallates with shorter chains demonstrated the strongest inhibitory effects. Our findings indicate that shorter alkyl gallates are effective in inhibiting enzymatic digestion of starch and therefore may have potential in modulating glycemic response.

Oral intake of slowly digestible α-glucan, isomaltodextrin, stimulates glucagon-like peptide-1 secretion in the small intestine of rats.

To investigate whether oral intake of highly branched α-glucan isomaltodextrin (IMD) could stimulate ileal glucagon-like peptide-1 (GLP-1) secretion, we examined (1) the digestibility of IMD, (2) the digestion and absorption rates of IMD, in rat small intestine and (3) portal GLP-1 concentration in rats given IMD. In Expt 1, ileorectostomised rats were given a 3 % IMD diet for 10 d. Separately, a 16-h in vitro digestion of IMD, using porcine pancreatic α-amylase and brush-border membrane vesicles from rat small intestine, was conducted. In Expt 2, upon 24-h fasting, rats were given any of glucose, IMD and high-amylose maize starch (HAMS) (1 g/kg of body weight). In Expt 3, caecectomised rats were given 0·2 % neomycin sulphate and a 5 % IMD diet for 10 d. The in vivo and in vitro digestibility of IMD was 70-80 %. The fraction of IMD digested in vitro for the first 120 min was 67 % of that in maize starch. The AUC for 0-120 min of plasma glucose concentration was significantly lower in HAMS group and tended to be lower in IMD group than in the glucose group. Finally, we also observed that, when compared with control rats, glucose of IMD significantly stimulated and improved the concentration of portal active GLP-1 in antibiotic-administered, caecectomised rats. We concluded that IMD was slowly digested and the resulting glucose stimulated GLP-1 secretion in rat small intestine. Oral delivery of slowly released IMD glucose to the small intestine probably exerts important, yet unknown, physiological effects on the recipient.

Understanding the effect of freeze-drying on microstructures of starch hydrogels

Freeze-drying treatment results in a marked disordering of starch structures because of the freezing of water and the sublimation of ice crystals. The objective of this work is to evaluate how the freeze-drying affects short-range ordered and crystalline structure, the structural compactness, size of reassemblied aggregates, and mesh size of starch gel network, by use of fourier transform infrared spectroscopy, small angle X-ray scattering and X-ray diffraction. Gels prepared from normal (NMS gel) and high-amylose maize starch (G50 gel) were selected as the model materials. After freeze-drying treatment, the short-range ordered and crystalline structures, the structural compactness, and the mesh size of starch gel network reduced for both starch gels. Long-range periodicity of reassemblied aggregates decreased via thinned amorphous region but unchanged ordered region. Impressively, G50 gel which had more ordered structures and a stronger gel network exhibited a higher resistant ability to the destruction of freeze-drying, and then showed little changes in microstructures after being freeze-dried in comparison with NMS gel. The ordered structures, compact reassemblied aggregates, and high-density mesh size-containing gel network may show a higher resistance to the destruction effect of freeze-drying treatment. This work systematically reveals the structural changes of starch gels subjected to freeze-drying treatment, which provides an in-depth understanding of gels structural changes during processing.

Pyrraline Formation Modulated by Sodium Chloride and Controlled by Encapsulation with Different Coating Materials in the Maillard Reaction.

Advanced glycation end products (AGEs), which are present in heat-processed foods, have been associated with several chronic diseases. Sodium chloride (NaCl) modulates the formation of furfurals and acrylamide in the Maillard reaction; however, the effects of NaCl on AGE formation are inconsistent. In this study, we investigated the effects of NaCl on pyrraline formation using glucose-lysine model systems. NaCl, especially at 0.50%, promoted Maillard browning and pyrraline formation, with a simultaneous increase in the 3-deoxyglucosone concentration. To reduce the rate of pyrraline formation, NaCl coated with different gums and starches were used. The results showed that NaCl encapsulation is an effective approach to mitigate pyrraline and 3-deoxyglucosone formation. The content of NaCl in the microparticles were 284 ± 12, 269 ± 6, 258 ± 8, 247 ± 10, 273 ± 16, and 288 ± 15 mg/g (coated with waxy maize starch, normal maize starch, HYLON VII high amylose maize starch, gelatinized resistant starch, xanthan gum, and gum arabic, respectively). The heat resistance of the coating material was negatively correlated with the pyrraline and 3-deoxyglucosone formation, whereas the solubility of the coating material had the opposite results. Coating the material with gum had little effects on the reduction of pyrraline and 3-deoxyglucosone.

Chemical Cross-Linking Controls in Vitro Fecal Fermentation Rate of High-Amylose Maize Starches and Regulates Gut Microbiota Composition.

A slow fermentation rate of dietary fiber could result in a steady metabolite production release and even distribution in the entire colon, increasing the likelihood of meeting the energy requirements of the distal colon. In the present study, we modulated the fermentation rate in an in vitro human fecal fermentation model by applying chemical cross-linking modification to a type 2 resistant starch [i.e., high-amylose maize starch (HAMS)]. Cross-linking modification decreased the gas production (an indicator of the fermentation rate) of HAMS throughout the whole fermentation progress. The butyrate production rate of cross-linked starches decreased gradually with the increase of the cross-linking degree. Certain beneficial gut microbiota such as genera of Blautia and Clostridiales members were remarkably promoted by starches with low and medium cross-linking degrees, whereas HAMS with a high cross-linking degree obviously promoted the abundance of Bacteroides uniformis and Ruminococcus bromii. This finding reveals that cross-linking modification effectively controls the fermentation rate and highlights the modulation metabolite profiles and gut microbiota composition through chemical modification.

Effects of Resistant Starch Ingestion on Postprandial Lipemia and Subjective Appetite in Overweight or Obese Subjects.

Reports surrounding the role of resistant starch (RS) on postprandial lipemia in humans are scarce. The aim of the present study is to examine the effects of resistant starch on the postprandial lipemic response, subjective measures of appetite, and energy intake in overweight and obese subjects. In a randomized, single-blind, crossover study, 14 overweight/obese participants ate a high-fat breakfast (679 kcal, 58% from fat) and a supplement with native banana starch (NBS), high-amylose maize starch (HMS), or digestible maize starch (DMS) on three separate occasions. All supplements provided were matched by the available carbohydrate content, and the RS quantity in NBS and HMS supplements was identical. Appetite was estimated using visual analogue scale (VAS) and an ad libitum test meal. Postprandial glycemia, triglycerides, cholesterol, high-density lipoprotein (HDL) cholesterol, and insulin excursions did not differ between treatments. Subjective appetite measures of satiety were significantly increased after HMS; however, no effects on energy intake were observed during the ad libitum test meal. These findings suggest that a single acute dose of RS cannot be expected to improve postprandial lipemia in subjects with overweight or obesity on a high-fat meal. However, the potential benefits of long-term supplementation should not be ruled out based on these results.

Pigs Ferment Enzymatically Digestible Starch when it Is Substituted for Resistant Starch

ABSTRACTBackgroundFeeding behavior is controlled by satiety mechanisms, which are affected by the extent of starch digestion, and thus resistant starch (RS) intake. Alterations in feeding behavior to changes in RS intake may depend on the adaptation of processes involved when shifting from starch digestion to fermentation or vice versa.ObjectivesThe aim of this study was to investigate how growing pigs adapt their feeding behavior in response to increasing and decreasing dietary RS concentrations.MethodsThirty-six groups of 6 pigs (25.4 ± 2.8 kg; Hypor Libra × Hypor Maxter; male:female, 1:1) were fed diets containing 50% high-amylose maize starch (high RS; HRS) or waxy maize starch (low RS; LRS). Over 28 d, diets were exchanged following a 5-step titration (25% per step) that was executed in the upward (LH) or downward direction (HL). Twelve groups received a control diet to correct for changes over time. Individual feeding behavior and total tract starch digestion and fermentation were evaluated. The response in each parameter to increasing dietary HRS inclusion was estimated through the use of linear regression procedures, and tested for titration direction and sex effects.ResultsComplete substitution of LRS with HRS increased the proportion of starch fermented, which was greater in LH pigs than in HL pigs (17.6% compared with 8.18%; P < 0.001), and decreased the feed intake (106 g/d; P = 0.021) and meal size (12.6 g; P < 0.001) of LH pigs, but not of HL pigs. In LH pigs, the size of the starch fermentation response positively correlated with the size of the feed intake response (r = 0.90, P < 0.001).ConclusionsThe attenuated response in starch fermentation in HL pigs indicates that pigs adapt more slowly to dietary supply of digestible starch than to RS, consequently resulting in fermentation of enzymatically digestible starch. Feed intake and feeding behavior only changed in pigs poorly adapting to RS, indicating that adequacy of adaptation, rather than RS itself, drives feed intake. These findings stress the importance of diet history for nutrient digestion and feeding behavior.

Gut microbial metabolite butyrate protects against proteinuric kidney disease through epigenetic- and GPR109a-mediated mechanisms.

Butyrate is a short-chain fatty acid derived from the metabolism of indigestible carbohydrates by the gut microbiota. Butyrate contributes to gut homeostasis, but it may also control inflammatory responses and host physiology in other tissues. Butyrate inhibits histone deacetylases, thereby affecting gene transcription, and also signals through the metabolite-sensing G protein receptor (GPR)109a. We produced an mAb to mouse GPR109a and found high expression on podocytes in the kidney. Wild-type and Gpr109a-/- mice were induced to develop nephropathy by a single injection of Adriamycin and treated with sodium butyrate or high butyrate-releasing high-amylose maize starch diet. Butyrate improved proteinuria by preserving podocyte at glomerular basement membrane and attenuated glomerulosclerosis and tissue inflammation. This protective phenotype was associated with increased podocyte-related proteins and a normalized pattern of acetylation and methylation at promoter sites of genes essential for podocyte function. We found that GPR109a is expressed by podocytes, and the use of Gpr109a-/- mice showed that the protective effects of butyrate depended on GPR109a expression. A prebiotic diet that releases high amounts of butyrate also proved highly effective for protection against kidney disease. Butyrate and GPR109a play a role in the pathogenesis of kidney disease and provide one of the important molecular connections between diet, the gut microbiota, and kidney disease.-Felizardo, R. J. F., de Almeida, D. C., Pereira, R. L., Watanabe, I. K. M., Doimo, N. T. S., Ribeiro, W. R., Cenedeze, M. A., Hiyane, M. I., Amano, M. T., Braga, T. T., Ferreira, C. M., Parmigiani, R. B., Andrade-Oliveira, V., Volpini, R. A., Vinolo, M. A. R., Mariño, E., Robert, R., Mackay, C. R., Camara, N. O. S. Gut microbial metabolite butyrate protects against proteinuric kidney disease through epigenetic- and GPR109a-mediated mechanisms.

Effect of mucin 4 allele on susceptibility to experimental infection with enterotoxigenic F4 Escherichia coli in pigs fed experimental diets

BackgroundThis study investigated the validity of the DNA-marker based test to determine susceptibility to ETEC-F4 diarrhoea by comparing the results of two DNA sequencing techniques in weaner pigs following experimental infection with F4 enterotoxigenic Escherichia coli (ETEC-F4). The effects of diet and genetic susceptibility were assessed by measuring the incidence of piglet post-weaning diarrhoea (PWD), faecal E. coli shedding and the diarrhoea index.ResultsA DNA marker-based test targeting the mucin 4 gene (MUC4) that encodes F4 fimbria receptor identified pigs as either fully susceptible (SS), partially or mildly susceptible (SR), and resistant (RR) to developing ETEC-F4 diarrhoea. To further analyse this, DNA sequencing was undertaken, and a significantly higher proportion of C nucleotides was observed for RR and SR at the XbaI cleavage site genotypes when compared to SS. However, no significant difference was found between SR and RR genotypes. Therefore, results obtained from Sanger sequencing retrospectively allocated pigs into a resistant genotype (MUC4–), in the case of a C nucleotide, and a susceptible genotype (MUC4+), in the case of a G nucleotide, at the single nucleotide polymorphism site. A total of 72 weaner pigs (age ~ 21 days), weighing 6.1 ± 1.2 kg (mean ± SEM), were fed 3 different diets: (i) positive control (PC) group supplemented with 3 g/kg zinc oxide (ZnO), (ii) negative control (NC) group (no ZnO or HAMSA), and (iii) a diet containing a 50 g/kg high-amylose maize starch product (HAMSA) esterified with acetate. At days five and six after weaning, all pigs were orally infected with ETEC (serotype O149:F4; toxins LT1, ST1, ST2 and EAST). The percentage of pigs that developed diarrhoea following infection was higher (P = 0.05) in MUC4+ pigs compared to MUC4– pigs (50% vs. 26.8%, respectively). Furthermore, pigs fed ZnO had less ETEC-F4 diarrhoea (P = 0.009) than pigs fed other diets, however faecal shedding of ETEC was similar (P > 0.05) between diets.ConclusionThese results confirm that MUC4+ pigs have a higher prevalence of ETEC-F4 diarrhoea following exposure, and that pigs fed ZnO, irrespective of MUC4 status, have reduced ETEC-F4 diarrhoea. Additionally, sequencing or quantifying the single nucleotide polymorphism distribution at the XbaI cleavage site may be more reliable in identifying genotypic susceptibility when compared to traditional methods.

In vitro fecal fermentation of propionylated high-amylose maize starch and its impact on gut microbiota

Resistant starch (RS) acylated with propionate groups is of particular interest in terms of their capacity to deliver specific short-chain fatty acids (SCFAs) to the colon with health benefits. In the present study, we fabricated propionylated high-amylose maize starches with different degrees of substitution (DS), and monitored the in vitro human fecal fermentation profiles. Propionylated modification did not change the slow gas production properties of high-amylose maize starch throughout the whole fermentation period. The final concentration of propionate (13.68–21.10 mM) produced by propionylated starch fermentation enhanced gradually with increase of DS value, resulting from the release of introduced propionyl groups. Certain beneficial gut microbiota such as Roseburia, and Blautia were obviously promoted, suggesting that propionylated starch could regulate the composition of gut microbiota. The results may facilitate the design and manufacture of functional food products with the aim of improving colonic health.

Digestibility and Acceptability of Wheat Flour Cookies Partially Substituted with High Amylose Maize Starch.

Cookies are one of the most consumed bakery products and the formulation could be modified to consider them as a functional food. The high amylose maize starch (HAMS) is considered as resistant starch (RS) type 2. The objective of this work was to assess the starch fractions, texture, sensory properties and acceptability of wheat flour cookies added with HAMS at different percentages. Adding 15% of HAMS into the formulation increased the amount of RS from 2.3 to 12.8%. In sensory analysis, children and adults showed a good acceptability of cookies since the addition of HAMS did not result in significant changes in flavor or color. Cookies made with HAMS could be considered as functional foods since they had an acceptable texture and low caloric content.