High-amylose Maize Research Articles

Insights into the structural, morphological, and thermal property changes in simulated digestion and fermentability of four resistant starches from high amylose maize starch

Changes in the structural, morphological, and thermal properties of four types of resistant starch (RS), including native (RS2), retrograded (RS3), chemically modified with octenyl succinic anhydride (RS4), and complexed with stearic acid (RS5), were investigated and compared in salivary, salivary-gastric, and salivary-gastric-intestinal digestion. In the process of digestion, the crystal types of RS2, RS3, RS4, and RS5 remained unchanged, maintaining a B-type structure, except for the missing V-type structure of RS5. The total short-chain fatty acid yield of RS2 was significantly higher than that of RS3, RS4, and RS5 at 6 and 12 h of fermentation. RS2 and RS4 had a better proliferation effect on Bifidobacterium in late fermentation than RS3 and RS5, while RS3 could promote proliferation to a larger extent in early fermentation. RS2, RS3, and RS5 had more obvious proliferation effects on Lactobacillus in the late fermentation period. This work suggests that the type of RS plays an important role in influencing the structural and digestive properties of RS during gastrointestinal digestion and can be used to develop formulations of healthy starch-based products with desired functionalities.

Physicochemical, functional properties, in vitro starch digestibility and estimated glycaemic index of composite flour influenced by resistant starch

There has been increasing demand for resistant starch-enriched food products with a low glycaemic index (GI) as consumers nowadays are aware to improve health status. Therefore, the present study was carried out to investigate the effect of different substitution levels of type-2 resistant starch (high-amylose maize starch) (HM) into wheat flour. In this study, wheat flour sample (control) and six test composite flour samples comprising wheat flour substituted with 5%, 10%, 15%, 20%, 25% and 30% of HM powder were analyzed to compare their physicochemical characteristics, functional properties, in vitro starch digestibility and expected glycaemic index (eGI). The results revealed that the incorporation of HM had resulted in increased moisture (12.70 – 13.31%) and total dietary fibre (TDF) (0.19 – 0.46%), as well as a decreased proportion of ash, fat, and protein. The carbohydrate and energy values were not significantly different upon the increasing percentage of HM (p>0.05). Mineral analysis showed that HM composite flour had significantly lower Mg, Ca, K, P, Fe, Zn and Se than the control. HM composite flour exhibited greater water holding, water holding capacity, oil holding capacity and swelling power than the control sample. The hydrolysis index and eGI of HM composite flour decreased with higher HM substitution. In conclusion, HM composite flours showed a good potential to be used in functional food, where positive impacts have been observed for in vitro starch digestibility and eGI characteristic.

Different starch varieties influence the complexing state and digestibility of the resulting starch-lipid complexes

In this study, we investigated the complexing state and digestibility of complexes formed between myristic acid (MA) and several varieties of starch (maize starch, MS; waxy maize starch, WS; high amylose maize starch, HMS; rice starch, RiS; cassava starch, CS; potato starch, PS). The resistant starch (RS) content, complexing index, and degree of the structural order of HMS-MA and MS-MA complexes were significantly higher (p < 0.05) than those of the other complexes. Notably, the RS increments of MS-MA complexes were the highest (14.10%). CS-MA, MS-MA and RiS-MA complexes showed better thermal stability of starch than the other complexes. The MA molecules were primarily physically embedded outside the helical structure of starch in WS-MA and PS-MA complexes. Additionally, CS-MA complexes possessed the highest relative number of physically embedded MA molecules. Moreover, the distribution of physically embedded MA molecules in WS-MA, CS-MA, and PS-MA complexes was more homogeneous than that in the other complexes. The weight-average molecular weight of amylose, average chain length of amylopectin side chains, and the proportion of chains with a degree of polymerization of 6–12 and 25–36 greatly affected their interactions with MA molecules. These results indicated that starch types substantially influenced the digestibility of the complexes, which was closely related to their complexing state and structural order.

Encapsulation and retention profile of thymol in the preformed “empty” V‐type starch inclusion complex

AbstractStarch, especially its amylose component can form inclusion complex (IC) with various small molecules, such as flavor and aroma compounds. Complexation of flavor compounds using starch matrices is driven by the hydrophobic interaction and the successful complexation may increase the retention of flavor compounds. In the present study, thymol (2‐isopropyl‐5‐methylphenol) at two different concentrations was introduced into three types of V‐type crystalline starches that have different inner helical cavity size, namely V6h, V7, and V8, and the formed ICs were characterized by X‐ray diffraction (XRD) and differential scanning calorimetry (DSC). The encapsulation efficiency (EE), loading efficiency (LE), and retention profile were determined by gas chromatography‐mass spectrometry (GC‐MS). The results indicated that when preparing ICs using V6h high amylose maize starch (HAMS) at a starch/thymol mass ratio of 2:1, the helical cavity of V6h helices was expanded and resulted in the formation of V7 crystals. Such circumstance could be owing to the cyclic structure of thymol and caused the minor phase transition at T2 of around 110°C observed in DSC. While in other conditions, the complexation with thymol did not alter the structure of starch. The EE and LE results suggested that V6h‐type HAMS exhibits higher capability to encapsulate thymol compared to V7 and V8 HAMS. All ICs demonstrated potent flavor retention ability and retained more than 70% of thymol after 8 h treatment. This study suggested that preformed “empty” V‐type starch could act as a potential matrix to encapsulate thymol, and this encapsulation technology should enable targeted applications of thymol for food processing and formulation applications.

For efficient treatment of starch using aqueous ionic liquid at room temperature

Considering the renewability and chemical versatility of natural biopolymers, innovative solvation processes to efficiently disrupt the native supramolecular structures of (namely dissolve/gelate) natural polymers for their modification, derivation, and materials fabrication are highly demanded. This work compares the structural disorganization behavior at room temperature among waxy maize, high-amylose maize, cassava and potato starches with the 6:4 (wt/wt) 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc])/water mixture using rapid visco analysis (RVA), scanning electron microscopy (SEM), X-ray diffraction (XRD), small-angle X-ray scattering, Fourier-transform infrared (FTIR), and Raman spectroscopy. All the viscosity, morphological and structural changes show the greater susceptibility of the two A-type (cassava and waxy maize) starches to structural disruption with the aqueous IL than the two B-type (potato and high-amylose maize) ones, while cassava starch is most susceptible. The four starches, once ball-milled (for up to 5 min), display an immediate increase in viscosity with time in RVA, while a lag in viscosity increase for native waxy maize and cassava starches without ball-milling and barely any viscosity change for high-amylose maize and potato starches can be observed. This indicates that the easiness of starch gelation by the aqueous IL is not directly linked to amylose content but is controlled by the granule surface compactness (namely, how easily the aqueous IL can reach and disrupt the most vulnerable parts inside the starch granule and subsequently cause the destruction of the rest parts and the breakdown of the whole granule). The findings can provide insights into developing low-energy processes for starch processing with aqueous ILs.

Targeted Delivery of Butyrate Improves Glucose Homeostasis, Reduces Hepatic Lipid Accumulation and Inflammation in db/db Mice.

Butyrate produced by the gut microbiota has beneficial effects on metabolism and inflammation. Butyrate-producing bacteria are supported by diets with a high fiber content, such as high-amylose maize starch (HAMS). We investigated the effects of HAMS- and butyrylated HAMS (HAMSB)-supplemented diets on glucose metabolism and inflammation in diabetic db/db mice. Mice fed HAMSB had 8-fold higher fecal butyrate concentration compared to control diet-fed mice. Weekly analysis of fasting blood glucose showed a significant reduction in HAMSB-fed mice when the area under the curve for all five weeks was analyzed. Following treatment, fasting glucose and insulin analysis showed increased homeostatic model assessment (HOMA) insulin sensitivity in the HAMSB-fed mice. Glucose-stimulated insulin release from isolated islets did not differ between the groups, while insulin content was increased by 36% in islets of the HAMSB-fed mice. Expression of insulin 2 was also significantly increased in islets of the HAMSB-fed mice, while no difference in expression of insulin 1, pancreatic and duodenal homeobox 1, MAF bZIP transcription factor A and urocortin 3 between the groups was observed. Hepatic triglycerides in the livers of the HAMSB-fed mice were significantly reduced. Finally, mRNA markers of inflammation in liver and adipose tissue were reduced in mice fed HAMSB. These findings suggest that HAMSB-supplemented diet improves glucose metabolism in the db/db mice, and reduces inflammation in insulin-sensitive tissues.

Can butyrate prevent colon cancer? The AusFAP study: A randomised, crossover clinical trial

Increased colonic butyrate from microbial fermentation of fibre may protect from colorectal cancer (CRC). Dietary butyrylated high amylose maize starch (HAMSB) delivers butyrate to the large bowel. The objective of this clinical trial (AusFAP) is to evaluate potential chemoprotective effects of HAMSB on polyposis in individuals with a genetic form of colon cancer, Familial Adenomatous Polyposis (FAP).The study is a multi-site, double blind, randomised, placebo-controlled crossover trial undertaken at major hospitals in Australia. After a baseline endoscopy participants consume either 40g/day of HAMSB or placebo (low amylose maize) starch for 26 weeks. After another endoscopic examination participants consume the alternate starch for 26 weeks. A third endoscopy at 52 weeks is followed by 26 weeks' washout and a final endoscopy at 78 weeks. Primary outcome measure is the global large bowel polyp number. Secondary measures include global polyp size counts, and number and size of polyps at two tattoo sites: one cleared of polyps at baseline, and another safely chosen with polyps left in situ during the study. Other secondary outcome measures include the effects of intervention on cellular proliferation in colonic biopsies, faecal measures including short chain fatty acid concentrations, and participants’ dietary intakes. Generalized linear mixed models analysis will be used to estimate differences in primary outcomes between intervention and placebo periods.This study represents the first clinical evaluation of the effects of increased colonic butyrate on polyp burden in FAP which, if effective, may translate to lower risk of sporadic CRC in the community.Australian New Zealand Clinical Trials Registry Number: 12612000804886.

Propionylated high-amylose maize starch alleviates obesity by modulating gut microbiota in high-fat diet-fed mice

Obesity threatens human health worldwide, and mounting findings have found that gut microbiota (GM) changes induced by diet intervention influence its development. This study aims to investigate the anti-obesity effects and GM changes of propionylated high-amylose maize starch (PS) in C57BL/6J mice fed with high-fat diet (HFD). In our results, PS decreased the body weight of HFD-fed mice after 8 weeks and regulated the glucose stability and insulin resistance. High-amylose maize starch (HAMS) and PS regulated the serum lipid levels and inflammatory response. Moreover, PS yielded more propionate relative to HAMS, proving that introduced propionyl groups could be released in the colon. 16S rRNA results showed that PS altered GM with the increase of bacteria (S24-7 and Ruminococcus) and decrease of harmful genera, which is linked to the anti-obesity effect. Our results provide a reference for the design of functional dietary fibers inducing high propionate production and GM modulation.

Stabilization of emulsions by high-amylose-based 3D nanosystem

High-amylose maize starch (HAS) was used to produce a fibrous 3D network nanosystem aiming at providing an efficient and stable emulsion stabilizer characterized by being robust against storage, freeze-thawing, high temperatures and mechanical shearing. This approach is principally different from the usually applied stabilization systems based on surfactants or small solid particles. Here, we utilized a sodium hydroxide-based low-temperature, chemical gelatinization protocol to minimize molecular degradation, and ethanol nanoprecipitation to reassociate the polysaccharides nanoparticles (NPs) to form a 3D nanosystem. Octenyl succinic anhydride (OSA) substitution was used for modulation of the amphiphilic properties of the nanosystem to enhance the emulsfying capacity. With increased OSA substitution, light transmittance of the NPs solutions increased and the size distribution of the NPs decreased down to 100 nm. The obtained emulsions were characterized by being water in oil (W/O) systems, and the NPs were distributed in the oil phase. OSA substitution and NPs concentration contributed combinedly to the emulsification capacity. The nanosystem, at 5% concentration with 20% OSA modification, had droplets of approximately 1 μm in diameter, and could withstand a 60-day-long storage, five-cycle freeze-thaw and thermal stability tests. In addition, it also displayed higher mechanical stabilities to shear-thinning. • High amylose maize starch-based 3D network was processed by a simple method. • Such nanosystems can stabilize the emulsions with high performance. • The emulsions were resistant to storage, freeze-thaw, heat, and mechanical shear. • The emulsion droplets were restricted in the range from 1 to a few μm.

Effects of water/ionic liquid ratios on the physicochemical properties of high amylose maize starch-lauric acid complex

This study examined high amylose maize starch (HAMS) treated with different ratios of a water/ionic liquid (IL) mixture and mixed with lauric acid (LA) and heated to form an amylose-lipid complex. IL can destroy the granule structure of starch, which releases more linear starch chains during the subsequent heating process and promotes the complexation reaction between HAMS and LA. Following the IL treatment of starch, HAMS's diffraction intensities, thermal stability and short-range order structure all decreased. The diffraction intensity of HAMS-LA complexes showed the following order: water:IL-4:1 > water:IL-8:1 > water:IL-2:1 > water:IL-11:1 > water:IL-0.5:1 > untreated sample. The creation of the V-type complex, according to a thermogravimetric study, improved the thermal stability of IL-treated HAMS. Results from Fourier transform infrared and Raman spectroscopy indicate that when IL-treated HAMS interacted with LA, the degree of short-range order structure of complexes increased. • The formation of HAMS-lipid complex was affected by the ratio of water/AMIMCL. • The moderate concentration of AMIMCL would conductive to inclusion complex production. • AMIMCL pretreatment could improve the complexation ability of HAMS.

Microstructures of Starch Granules with Different Amylose Contents and Allomorphs as Revealed by Scattering Techniques.

In this study, as-is (ca. 12% moisture by mass) and hydrated (50% water by mass) granules of waxy potato (WP), waxy wheat (WW), waxy maize, normal maize, and high-amylose maize (HAM) starches were investigated by using small-angle neutron and X-ray scattering (SANS and SAXS), wide-angle X-ray scattering, and ultra-small-angle neutron scattering. The SANS and SAXS data were fitted using the two-phase stacking model of alternating crystalline and amorphous layers. The partial crystalline lamellar structures inside the growth rings of granules were analyzed based on the inter-lamellar distances, thicknesses of the crystalline lamellae and amorphous layers, thickness polydispersities, and water content in each type of layer. Despite having a longer average chain length of amylopectin, the WP and HAM starches, which had B-type allomorph, had a shorter inter-lamellar distance than the other three starches with A-type allomorph. The WP starch had the most uniform crystalline lamellar thickness. After hydration, the amorphous layers were expanded, resulting in an increase of inter-layer distance. The low-angle intensity upturn in SANS and SAXS was attributed to scattering from interfaces/surfaces of larger structures, such as growth rings and macroscopic granule surfaces. Data analysis methods based on model fitting and 1D correlation function were compared. The study emphasized─owing to inherent packing disorder inside granules─that a comprehensive analysis of different parameters was essential in correlating the microstructures with starch properties.

Prebiotic intervention with HAMSAB in untreated essential hypertensive patients assessed in a phase II randomized trial.

Fibers remain undigested until they reach the colon, where some are fermented by gut microbiota, producing metabolites called short-chain fatty acids (SCFAs), such as acetate and butyrate1. SCFAs lower blood pressure in experimental models2-5, but their translational potential is unknown. Here we present the results of a phase II, randomized, placebo-controlled, double-blind cross-over trial (Australian New Zealand Clinical Trials Registry ACTRN12619000916145) using prebiotic acetylated and butyrylated high-amylose maize starch (HAMSAB) supplementation6. Twenty treatment-naive participants with hypertension were randomized to 40 g per day of HAMSAB or placebo, completing each arm for 3 weeks, with a 3-week washout period between them. The primary endpoint was a reduction in ambulatory systolic blood pressure. Secondary endpoints included changes to circulating cytokines, immune markers and gut microbiome modulation. Patients receiving the HAMSAB treatment showed a clinically relevant reduction in 24-hour systolic blood pressure independent of age, sex and body mass index without any adverse effects. HAMSAB increased levels of acetate and butyrate, shifted the microbial ecosystem and expanded the prevalence of SCFA producers. In summary, a prebiotic intervention with HAMSAB could represent a promising option to deliver SCFAs and lower blood pressure in patients with essential hypertension.

S-57-3: GUT MICROBIAL METABOLITES LOWER 24-HOUR SYSTOLIC BLOOD PRESSURE IN HYPERTENSIVE PATIENTS

Objective: Clinical evidence supports that dietary fibre intake lowers blood pressure (BP). Dietary fibres remain intact until they reach the colon. There, they are fermented by gut microbial communities to produce metabolites, particularly short-chain fatty acids (SCFAs). Previous studies, including our own, have demonstrated that supplementation with the SCFAs acetate and butyrate lower BP in experimental models. However, whether dietary supplementation with SCFAs in humans elicits the same reduction in BP is undetermined. We aimed to establish whether a SCFAs-enriched dietary supplement lowers 24-hour BP in participants with essential hypertension. Design and method: Twenty untreated hypertensive participants, diagnosed by 24-hour BP using a Mobil-O-Graph device, were recruited for a phase II randomized placebo-controlled double-blind crossover trial. Participants were randomized to receive a daily intervention of 40 g/day of acetylated and butyrylated high amylose maize starch (HAMSAB) or 40 g/day of regular flour or cornflour (placebo). The dietary intervention lasted three weeks, with a three-week washout period following completion. The primary endpoint was a change in 24-hour systolic BP. Secondary endpoints included SCFA levels and changes in gut microbiome. Results: Participants were on average 55.8 ± 11.2 (mean ± SD) years of age, had a body mass index (BMI) of 25.7 ± 2.5km2/m, and 30% were female. The baseline 24-hour systolic BP was 136 ± 6mmHg. The dietary intervention was well-tolerated and had high acceptability with 93% compliance. There was no difference in 24-hour systolic BP between the baseline visits (P = 0.55) and the placebo (P = 0.18). After 3-weeks on the HAMSAB diet, the placebo-subtracted treatment 24-hour systolic BP difference was 6.1 ± 9.9mmHg (P = 0.027). These observations were independent of age, sex, BMI and study arm. Day and night systolic BP were reduced by 6.5 ± 12.3mmHg (P = 0.01) and 5.7 ± 9.8mmHg (P = 0.02), respectively, and 24-h central BP by 7.2 ± 14.7 mmHg (P = 0.005). There was no change in stroke volume, cardiac output or heart rate; however, HAMSAB reduced total vascular resistance (P = 0.049). Compared to the placebo, the HAMSAB diet elevated acetic and butyric acid levels by 7.8-fold (P = 0.016). HAMSAB also shifted the gut microbial ecosystem (P = 0.037) and increased the prevalence of the acetate and butyrate producers Parabacteroides distasonis and Ruminococcus gauvreauii (q-value &lt; 0.05). Conclusions: We observed a clinically relevant reduction in 24-hour systolic BP in participants with essential hypertension treated with the gut microbial-derived metabolites acetate and butyrate. These metabolites may represent a novel option for lowering BP. Low fibre diets and reduced gut microbial metabolites may be one of the principal reasons for the hypertension epidemic in Western countries.

Indole acetylated high-amylose maize starch: Synthesis, characterization and application for amelioration of colitis

Tryptophan metabolites such as indole-3-acetic acid (IAA) are critical for gut health, through their binding to the aryl hydrocarbon receptor (AhR), and may be useful for treatment of gastrointestinal diseases. Delivery of IAA to the colon is necessary, and one strategy is use of esterified starches which get digested in the colon by gut microbes. High amylose maize starch (HAMS) resists digestion in the upper gastrointestinal tract and is fermented by gut microbiota to release short-chain fatty acids (SCFAs), which are also beneficial to intestinal homeostasis. IAA esterified to HAMS (HAMSIAA) was synthesized with different degrees of substitution (DSs) by controlling the ratio of IAA vs HAMS. Successful incorporation of indole acetyl group was verified by NMR and FTIR spectra. XRD revealed that the crystalline type of HAMSIAA changed from B to V-type. SEM showed the destroyed surface of the starch granules. HAMSIAA with DS ~ 0.3 effectively increased IAA in the colon, to levels unachievable by oral IAA delivery. HAMSIAA increased pathways downstream of AhR activation, including CYP1A1 mRNA expression and IL-22 protein levels, and greatly improved DSS-induced colitis. HAMSIAA could serve as an ideal means for colon-targeted delivery of IAA and a promising nutraceutical for amelioration of inflammatory conditions.

Effects of structure and physical chemistry of resistant starch on short-term satiety

The present study investigated the effects of structure and physical chemistry and of resistant starch on short-term satiety in mice using three types of resistant starch (RS): high-amylose maize starch (HMS, RS2), retrograded HMS (RS3), and octenyl succinic anhydride (OSA)-modified HMS (RS4). RS3 resulted in the greatest satiety, as indicated by the lowest food intake over 4 h, followed by RS4 and RS2. RS3 also yielded the lowest postprandial blood glucose peak, blood glucose fluctuation, and gastric emptying rate, which was conducive to the continuation of satiety. Structural and physicochemical analysis revealed that the three resistant starches differed significantly in terms of particle size, chain-length distribution, and swelling power, which were all significantly associated with short-term satiety (Pearson correlation analysis). These findings could provide a theoretical basis for designing raw materials for high-satiety-inducing foods for patients with type 2 diabetes and obesity. • Type Ⅲ resistant starch (RS3) resulted in greater satiety than RS4 and RS2. • RS3 caused stable postprandial blood glucose and the lowest insulin level. • Satiety was positively correlated with the swelling power of resistant starch.

Effect of popping water content and amylose/amylopectin ratio on the physical properties of expanded starch products with different shear histories

SummaryAerated starch products are a staple of the food industry, with particular relevance in the snack market. Water plays a crucial role in the formation of such products due to its utility both as a blowing agent and as a starch plasticiser. Amylose/amylopectin ratio and shear are traditionally also important factors in starch expansion. In this study, waxy, normal and high amylose maize starch variants were expanded using a rice‐cake style popping head at water contents between 0% and 24%. This range of water contents was achieved by drying the material at 105 °C and then rehydrating by suspension over water at 50 °C until the desired water content was reached prior to popping. Sample types were further subdivided into low shear (native) and high shear (extruded) processing prior to popping. Processing history, amylose content and water content all influenced the water interaction properties of the popped products. However, density was largely governed by water content with little apparent influence of other factors. An optimum water content range to produce low‐density (and therefore high desirability in industry) products was identified in the region of ~15–21% water. Samples popped below this range exhibited suboptimal expansion whilst those popped at higher water contents experienced violent blowout.

The effects of different types of high-amylose maize starches on viscosity and digestion of acidified milk gels

High-amylose maize starch (HAMS) can provide dietary fiber to foods. In this study, we investigated the effects of three HAMSs (Gelose 50, Hylon VII, and NAFU50) on the functionality of casein (CA) and/or whey protein (WP) networks in acidified milk gels using normal maize starch (NMS) as a control thickener. When compared with NMS, HAMSs performed better in increasing the resistant starch content (RS), storage modulus, loss modulus, and complex viscosity of all the milk gels. The results are attributed to the retention of the starch granular integrity of HAMSs during the preparation of the milk gels, as observed by microscopy. HylonVII exhibited the highest RS and viscosity in all milk gel systems, especially in WP gels (71.8 % RS and >3000 Pa.s at 1 Hz viscosity). Our data provide support for the potential of using HAMS to develop healthier yogurt products using functional thickeners from natural sources.

Formation of Starch-Lipid Complexes during the Deep-Frying Process and Its Effects on Lipid Oxidation.

In the present study, maize starch (MS), potato starch (PS), high-amylose maize starch (HAMS), and wheat starch (WS) were deep-fried in soybean oil that was continuously heated for 40 h under 180 °C. The thermodynamic and pasting properties of deep-fried starch samples were determined. The results suggested that starch–lipid complexes formed with the extension of frying oils’ usage; however, their number was not dependent on the frying oils’ life cycle. Importantly, the results of pasting properties revealed the following strength of intermolecular force in deep-fried starch samples: PS > MS > HAMS > WS. The results of XRD and FTIR analysis confirmed the formation of starch–lipid complexes during the deep-frying process. Furthermore, the results of the in vitro digestibility of deep-fried starch revealed that the formation of starch–lipid complexes inhibited the swelling of starch granules and prevented the entrance of amylase into the interior. Additionally, the results of the oxidation stability of deep-frying oil indicated that the formation of starch–lipid complexes did not alter the trend of lipid oxidation as an effect of the limited number of starch–lipid complexes. These results could have critical implications for the development of healthier deep-fried foods.

Pasting and gelation behaviors and in vitro digestibility of high-amylose maize starch blended with wheat or potato starch evaluated at different heating temperatures

Different approaches have been adopted to overcome the inherent shortcomings of native starches, and blending of different native starches has attracted much attention due to the “clean-label” feature and the low processing effort and cost. In the current study, we blended high-amylose maize starch (HA7) with wheat (WHE) or potato (POT) starch at 1:1 ratio (dry weight basis; dwb) and then comprehensively examined their thermal properties, pasting and gelling behaviors over the heating temperature range of 95–140 °C, and in vitro digestibility in comparison with three individual starches. With an excess amount of water (starch:water = 1:3), gelatinization of individual starches generally appeared to be independent in the two starch blends. An exceptionally low percentage of retrogradation was observed for gelatinized HA7-WHE blend during cold storage, which could be partially ascribed to the formation of a large amount of amylose-lipid complexes (ALC). Greater resistance to thermal degradation and thixotropic breakdown during pasting at 120 °C was found with HA7-WHE blend when compared with HA7-POT blend. Both starch blends could form gels with moderate strength (74.3–109.4 g) after cooking at 120 and 140 °C. The determined resistant starch (RS) and slowly digestible starch (SDS) contents of water-boiled HA7-WHE blend were higher than the calculated values when assuming simple additivity of the two starches. The interactions at both granular and molecular levels and the presence of ALC were responsible for the reported unique techno-functional attributes of HA7-WHE blend, which rendered it suitable for diverse food and industrial applications. • More amylose-lipid complex in high-amylose (HA7)-wheat (WHE) starch blend (1:1 dwb). • Gelatinized HA7-WHE blend had the least %retrogradation (9.2%) of all the starches. • HA7-WHE blend showed strong resistance against high-temperature cooking at 120 °C. • Starch blends had moderate gel strength (74.3–109.4 g) after 120 and 140 °C cooking. • Water-boiled HA7-WHE blend showed enhanced in vitro enzymatic resistance.

Ae1/Sbe1 maize-derived high amylose improves gut barrier function and ameliorates type II diabetes in high-fat diet-fed mice by increasing Akkermansia.

Type II diabetes mellitus (T2DM) has its origins in chronic inflammation due to immune dysregulation. Improving chronic inflammation can significantly reduce the probability of T2DM and the rate of disease progression. Resistance to starch 2 (RSII) high-amylose maize starch (HAMS) has been widely implicated in the improvement and regulation of T2DM. However, its exact molecular mechanisms have not been fully discovered. Here, we used CRISPR/Cas9 technology to knock out two starch-branching enzyme genes, Ae1 and Sbe1, in maize to obtain mutants containing higher levels of HAMS. In experiments in which HAMS was fed to mice on a high-fat diet (HFD), we confirmed the function of HAMS in ameliorating hyperglycemia. Mechanistically, we found that HAMS improves the gut barrier function by increasing the Akkermansia abundance in the gut. This increase led to the alleviation of chronic inflammation in mice on a HFD, resulting in improved insulin sensitivity and a decrease in blood glucose.