High Resistant Starch Research Articles

Structure, physicochemical, functional and in vitro digestibility properties of non-waxy and waxy proso millet starches

The structural, physicochemical, gel textural, rheological, and in vitro digestibility properties as well as their relationships of non-waxy proso millet starch (NPMS) and waxy proso millet starch (WPMS) were evaluated by taking normal corn starch (CS) and potato starch (PS) as controls. Proso millet starch was mostly polygonal or spherical, with an A-type crystalline structure. Proso millet starch contained more short-branched chains (DP 6–24) compared with CS and PS. WPMS possessed higher crystallinity and more short-range ordered structures than NPMS. NPMS displayed higher pasting temperature, retrogradation rate and shear thinning degree, and lower gelatinization temperature and enthalpy than WPMS. The hardness and chewiness of starch gel formed by NPMS were higher than those of WPMS. All starch samples exhibited shear thinning behavior in the steady-flow test and typical elastic solid behavior in the dynamic rheological test. Moreover, NPMS was considered a potential formula for functional foods, with its lower rapidly digestible starch (RDS) and higher resistant starch (RS) contents than WPMS, CS, and PS. This paper revealed the influence of amylose content and structure on the physicochemical properties of different proso millet starch.

Influence of Resistant Starch in Whole Rice on Human Gut Microbiota─From Correlation Implications to Possible Causal Mechanisms

Rice is the main staple food for a large population around the world, while it generally has a high glycemic index and low resistant starch (RS) content. Although many strategies have been applied to develop healthier rice products with increased RS contents, their actual effects on gut microbiota and human health remain elusive. In this review, currently available production methods of rice RS are briefly summarized, followed by a critical discussion on their interactions with gut microbiota and subsequent effects on human health, from correlation implications to causal mechanisms. Different contents, types, and structures of RS have been produced by strategies such as genetic manipulation and controlling cooking conditions. The difference can largely determine effects of rice RS on gut microbiota composition and metabolites by specific RS-gut microbiota interactions. This review can thus help the rice industry develop rice products with desirable RS contents and structures to generally improve human health.

The Influence of Macronutrient Intake towards Intestinal Mucus Production

Intestinal mucus layer plays a crucial role in protecting the epithelium layer and acts as a barrier to separate the epithelium layer from pathogenic microorganisms. The mucus is synthesized by the goblet cells located in the epithelium layer. The production of mucus inside the goblet cells is regulated by the expression of mucin gene family, such as MUC2 for the mucus production in jejunum, ileum, and colon. Recent studies had suggested the influence of macronutrient intake, such as carbohydrate and fat, in mucus production. High fiber diet and resistant starch consumption were found to positively affect mucus production through upregulating mucin gene expression. Meanwhile, high saturated fat diet was found to negatively affect mucus production by promoting ER stress and downregulating epithelial differentiation transcription factor (KLF4). Nonetheless, a low saturated fat diet was found to upregulate mucin expression. Unsaturated fat diet (oleic acid, linoleic acid, EPA, and DHA), on the other hand, decreased mucin expression by disrupting epithelial differentiation transcription factors (HATH1 and TLR4). Studies on the effect of dietary intake on mucus production are still limited, especially in the underlying molecular pathway. Therefore, further research on the molecular pathway on the effect of dietary intake on mucus production needs to be performed.

Preclinical Safety Assessment of Chemically Cross-Linked Modified Mandua Starch: Acute and Sub-Acute Oral Toxicity Studies in Swiss Albino Mice.

In the present era, 28 days of repeated-dose-toxicity study following the Organization for Economic Cooperation and Development (OECD) guidelines 407 is compulsory for every drug to go through phase 1 clinical trials. The increasing demand for high-resistant starch containing nutraceuticals and the applicability of modified starch in development of targeted drug delivery inspired us to investigate the toxic profile of mandua starch chemically cross-linked by epichlorohydrin and compare it with alkali-isolated starch in healthy adult Swiss albino mice, which can be the first step for exploring the use of epichlorohydrin-cross-linked mandua starch (ECC-MS) as a pharmaceutical excipient. Histopathological examinations of the kidney and liver did not expose noteworthy abnormalities in the treated mice. There were no clinical and mortality symptoms of toxicity observed during the repeated-dose-toxicity study. The oral consumption of ECC-MS did not pose any harm as it was neither lethal nor had any harmful hematological, biochemical, psychological, anatomical, and behavioral effects. The use of ECC-MS and alkali-isolated mandua starch (AMS) was found safe at a dose of 2000 mg/kg body weight in the acute toxicity study and at doses of 2000, 1500, and 1000 mg/kg body weight in the sub-acute toxicity study as no detrimental effects were observed after oral administration in mice for 14 and 28 days, respectively.

Sri Lankan traditional parboiled rice: A panacea for hyperglycaemia?

The research aimed to scientifically prove that parboiled Sri Lankan traditional rice elicits lower glycaemic responses comparative to raw unpolished or polished rice. Thus the proximate composition and glycaemic indices (GI) of raw, raw polished, and parboiled traditional Sri Lankan rice (Oryza sativa L.) varieties Godaheenati, Batapola el, Dik wee, Dahanala, Unakola samba, and Hangimuththan were studied as comparative data are not available. Cooked parboiled rice contained significantly high moisture (P<0.05) than raw or raw polished. Mineral content was low (<1.5%) regardless of processing. Crude protein was comparatively high (5.8-11.0% DM) with 2.1-5% (DM) fat with raw unpolished and parboiled having higher contents. Digestible starch of raw polished was highest compared to parboiled or raw unpolished (68.8-90.5% DM). Resistant starch was significantly (P<0.05) high in parboiled rice (1.1-7.2%) with the least total dietary fibre in raw polished rice. All varieties of parboiled and raw polished were found to elicit low GI and high GI respectively. High moisture, high resistant starch, and low starch in cooked parboiled rice contributed to low GI compared to raw unpolished or raw polished rice.

Screening of Induced Mutants Led to the Identification of Starch Biosynthetic Genes Associated with Improved Resistant Starch in Wheat.

Several health benefits are obtained from resistant starch, also known as healthy starch. Enhancing resistant starch with genetic modification has huge commercial importance. The variation of resistant starch content is narrow in wheat, in relation to which limited improvement has been attained. Hence, there is a need to produce a wheat population that has a wide range of variations in resistant starch content. In the present study, stable mutants were screened that showed significant variation in the resistant starch content. A megazyme kit was used for measuring the resistant starch content, digestible starch, and total starch. The analysis of variance showed a significant difference in the mutant population for resistant starch. Furthermore, four diverse mutant lines for resistant starch content were used to study the quantitative expression patterns of 21 starch metabolic pathway genes; and to evaluate the candidate genes for resistant starch biosynthesis. The expression pattern of 21 starch metabolic pathway genes in two diverse mutant lines showed a higher expression of key genes regulating resistant starch biosynthesis (GBSSI and their isoforms) in the high resistant starch mutant lines, in comparison to the parent variety (J411). The expression of SBEs genes was higher in the low resistant starch mutants. The other three candidate genes showed overexpression (BMY, Pho1, Pho2) and four had reduced (SSIII, SBEI, SBEIII, ISA3) expression in high resistant starch mutants. The overexpression of AMY and ISA1 in the high resistant starch mutant line JE0146 may be due to missense mutations in these genes. Similarly, there was a stop_gained mutation for PHO2; it also showed overexpression. In addition, the gene expression analysis of 21 starch metabolizing genes in four different mutants (low and high resistant starch mutants) shows that in addition to the important genes, several other genes (phosphorylase, isoamylases) may be involved and contribute to the biosynthesis of resistant starch. There is a need to do further study about these new genes, which are responsible for the fluctuation of resistant starch in the mutants.

Evaluation of in vitro and in vivo Glycemic Index of common staples made from varieties of White Yam (Dioscorea rotundata)

Consumption of high Glycemic Index (GI) foods is a risk factor for increasing prevalence of diabetes mellitus (DM). The extent of variation in starch digestibility and GI of Yam varieties and products is not yet fully understood. This study was therefore designed to evaluate in vitro and in vivo Glycemic Index properties of commonly consumed products prepared from varieties of White Yam. Four products (boiled, fried, pounded yam, and Amala) were prepared from 5 common varieties of Yam and evaluated for Digestible Starch (DS) and Resistant Starch (RS). Based on results, two products-pounded yam and Amala-were processed from three of the most popular varieties. Analysis of Rapidly Digestible Starch (RDS), Slowly Digestible Starch (SDS), and estimated in vitro GI (eGI) were then carried out in this stage. Glycemic Index (GI) of these products consumed by apparently healthy young adults were also determined. Variety Amula had highest DS in Amala (19.1/100 g) and pounded Yam (20.4/100 g) while variety Alumaco had highest RS in all the products (2.9–3.3/100 g). When compared with RS in its raw tuber, RS of Alumaco generally increased after processing. Variety Alumaco had lowest RDS in Amala (0.6/100 g) and pounded yam (0.3/100 g) while eGI was lowest in Alumaco made into Amala (53) and pounded yam (48). Assessment of GI resulted in high GI for all products across each variety. Irrespective of variety, processing Yam into Amala released RDS fraction faster when compared with pounded yam. Generally, even though the products are considered as having high GI, Amala raised eGI and GI faster than Pounded yam. Variety-Alumaco particularly showed favorable properties applicable to dietary management of diabetes. Exploring more processing methods and genetic diversity is recommended.

Physicochemical, functional and sensory properties of wheat noodles substituted by sorghum and mung bean flours

Noodles are flour-based processed products that are generally served as an alternative food to carbohydrates dense products. Nowadays, carbohydrate-based processed products, such as the production of non-wheat noodles and the substitution of non-wheat carbohydrate sources, are developed, mainly through the use of local food commodities as alternatives. The purpose of this research was to investigate the physicochemical qualities of wheat noodles substituted for local food ingredients such as sorghum flour and green beans via sticking properties, cooking quality, proximate analysis, and sensory characteristics. Resistant starch and dietary fibre content were the functional features studied. Five formulas were established, each with a different amount of wheat flour, sorghum flour and mung bean flour used in the processing, namely N1 (50:20:30), N2 (40:30:30), N3 (30:40:30), N4 (20:50:30), and N5 (10:60:30). The peak viscosity of the five composite flour formulae was 1421-1778, the breakdown value was 454-535, and the ultimate viscosity was 1967-2490, with a cooking loss of 10.69-23.21%. According to proximate analysis, the formulated noodles provide complete nutritional content to meet nutritional adequacy, namely 375-381 kcal/100 g. It not only has a great nutritional value, but it also has strong physiological advantages for the body due to the high concentration of dietary fibre (9.6-9.8%) and resistant starch (14.93-15.01%). The taste, texture, and aroma of the sample formulae N2, N3, and N5 are comparable to wheat-based noodles. The five wheat noodles substituted by sorghum and mung bean flour formulations were potentially developed into functional products with comprehensive nutritional content, high dietary fibre, and resistant starch. Further research is needed to confirm its functional properties on health.

Gluten-free noodles made based on germinated organic red rice: chemical composition, bioactive compounds, antioxidant activity and sensory evaluation

The purpose of this research was to find out the chemical composition, bioactive compound content, antioxidant activity, and sensory evaluation of gluten-free noodles made from organic red rice. The study was carried out by creating three formulations using germinated organic red rice flour, germinated Vigna radiata flour, and tapioca flour. Proximate analysis, resistant starch and dietary fibre were used to analyze the chemical composition. Phenolic and flavonoid compounds were among the bioactive compounds studied. The DPPH method was used to assess antioxidant activity. The findings revealed that all three formulations of gluten-free organic red rice noodles, formulations I, II, and III, had high fibre content, resistant starch, bioactive compounds, and antioxidant activity. According to sensory evaluation, gluten-free organic red rice noodles formulation I have the highest acceptance rate compared to organic red rice noodles formulations II and III. The amount of soluble dietary fibre was 0.79±0.08%, the amount of insoluble dietary fibre was 6.73±0.18%, and the amount of resistant starch was 7.56±0.02%. Total phenolics content (TPC) was 49.16±0.27%, total flavonoids content (TFC) was 53.36±0.86%, and the IC50 was 9665.84±72.39. The content of bioactive compounds and the IC50 of glutenfree organic red rice noodles have a significant and positive correlation. According to the study's findings, gluten-free organic red rice noodle formulation could be developed as a functional food high in dietary fibre, resistant starch, and antioxidants.

Physicochemical, Morphological, and Functional Properties of Starches Isolated from Avocado Seeds, a Potential Source for Resistant Starch.

This study compared the physicochemical and functional properties of starches from eight cultivars of avocado seeds. Amylose content, morphology, crystalline structure, swelling power, solubility, thermal and pasting properties, and in vitro digestibility were investigated. The results revealed that the apparent amylose content of starches from avocado seeds varied with different varieties. Light microscopic and scanning electron microscopic examination demonstrated that the eight starches differed slightly in terms of morphology and granule size. The X-ray diffraction and Fourier transform infrared spectroscopy analyses showed that the crystal structure and chemical linkage of the avocado seed starches were similar. However, the pasting, water solubility, and thermal properties of the eight avocado seed starches differed. Importantly, all the starches had high resistant starch content (>60%), with the highest found in Hass seeds (77.83%). To conclude, starch from avocado seeds has a high potential for use in the production of resistant starch.

Formation of Intermediate Amylose Rice Starch-Lipid Complex Assisted by Ultrasonication.

Due to the potential reduction in starch availability, as well as the production of the distinct physico-chemical characteristics of starch in order to improve health benefits, the formation of starch–lipid complexes has attracted significant attention for improving the quantity of resistant starch (RS) content in starchy-based foods. The purpose of this research was to apply ultrasonication to produce intermediate amylose rice (Oryza sativa L.) cv. Noui Khuea (NK) starch–fatty acid (FA) complexes. The effects of ultrasonically synthesized conditions (ultrasonic time, ultrasonic amplitude, FA chain length) on the complexing index (CI) and in vitro digestibility of the starch–FA complex were highlighted. The optimum conditions were 7.5% butyric acid with 20% amplitude for 30 min, as indicated by a high CI and RS contents. The ultrasonically treated starch–butyric complex had the highest RS content of 80.78% with a V-type XRD pattern and an additional FTIR peak at 1709 cm−1. The increase in the water/oil absorption capacity and swelling index were observed in the starch–lipid complex. The pasting viscosity and pasting/melting temperatures were lower than those of native starch, despite the fact that it had a distinct morphological structure with a high proportion of flaky and grooved forms. The complexes were capable of binding bile acid, scavenging the DPPH radical, and stimulating the bifidobacterial proliferation better than native starch, which differed depending on the FA inclusion. Therefore, developing a rice starch–lipid complex can be achieved via ultrasonication.

Physicochemical, Pasting Properties and In Vitro Starch Digestion of Chinese Yam Flours as Affected by Microwave Freeze-Drying.

Microwave freeze-drying (MFD) is a new freeze-drying technique, which differs from single microwave treatment; it involves simultaneous effects of microwave power, time, and the moisture state applied to the materials. In this study, the effects of MFD under various microwave power densities (0.5, 1.0, and 1.5 W/g) on the drying characteristics of Chinese yam slices and the physicochemical, pasting, and thermal properties as well as the starch digestibility of the flour were investigated using conventional hot air drying (HAD) at 50 °C as a control. Compared to HAD, MFD shortened the drying time up to 14.29~35.71%, with a higher drying efficiency at a high microwave power density (1.5 W/g). MFD yam flours provided benefits over HAD products in terms of color, water/oil absorption capacity, and solubility, exhibiting high hot-paste viscosity but low resistant starch content. The content of total starch and free glucose of the yam flour and its iodine blue value were significantly influenced by the drying method and the MFD process parameters (p < 0.05). MFD processing could disrupt the short-range ordered structure of yam starch. Among the MFD flours, samples dried by MFD at 1.5 W/g presented the highest ratio of peak intensity at 1047 and 1022 cm−1 (R1047/1022) value, gelatinization enthalpy, and resistant starch content. These results gave a theoretical foundation for the novel freeze-drying method that MFD applied to foods with a high starch content, enabling the production of a product with the desired quality.

Effect of steaming and roasting on the quality and resistant starch of brown rice flour with high amylose content

The high-amylose rice cultivar Dodamssal (DDS), a potentially nutritious functional food, contains resistant starch (RS). However, its RS content varies with the processing method used. In this study, heat treatment was used to produce rice powder with enhanced RS content. The rice powder quality was improved by steaming rough rice and brown rice for 30 min and roasting the brown rice at 240 °C for 10 min. Brown rice flour (BRF) made from steamed rough rice and roasted DDS (SRRD) had higher RS content (14%), ratio of fine particle sizes (0–20 μm), and gelatinization degree (GD), as well as lower mean particle size (51 μm) and in vitro glycemic index than did roasted DDS. Contrastingly, BRF prepared from steamed brown rice and roasted DDS with high GD had low RS content (12%) and high mean particle size (56 μm). Hence, SRRD-BRF improves powder quality and may be beneficial for nutritious functional food production.

Effects of the substitution of wheat flour with raw or germinated ayocote bean (Phaseolus coccineus) flour on the nutritional properties and quality of bread.

This study aimed to evaluate the potential of 10%, 20%, and 30% of raw (ARF) and germinated (AGF) ayocote bean flour as a partial substitute for wheat flour in breadmaking. Substitution with both ayocote bean flours modified the water absorption and development time while maintaining the dough stability. Supplemented breads had 13%, 51%, and 132% higher protein, mineral, and crude fiber content, respectively, than control bread (100% wheat). The breadmaking features, color and crumb firmness, were affected by the substitution level. Sensory analysis revealed that germination could improve the taste and smell of breads produced with ayocote bean flour. The sensory attribute scores of 10% AGF bread were comparable to those of the control bread. Supplementation reduced the in vitro protein digestibility, although the effect was less pronounced in 10% ARF and 20% AGF breads. The limiting amino acid score of supplemented breads increased up to 70%, which improved their protein digestibility-corrected amino acid scores. Supplementation with 20% or 30% of both ARF and AGF increased resistant starch values and decreased the total digestible starch of breads. Thus, the results showed that substituting wheat with ARF or AGF improves the nutritional properties of bread. However, low substitution levels should be selected to avoid a considerable decrease in physical and sensory properties. PRACTICAL APPLICATION: Substituting wheat flour with ayocote bean flour improved the nutritional value of bread. Germination of ayocote beans decreased the cooking stability of composite dough. Bread fortified with ayocote flour had high levels of essential amino acids. Bread with raw or germinated ayocote flours had high limiting amino acid scores. Composite bread had high resistant starch and low total digestible starch.

The Benefits of High-Resistant Starch and Beta-Carotene Snack in Ameliorating Atherogenic Index and Inflammation in Obesity

BACKGROUND: In obesity, lipid abnormalities may be related to the higher risk of cardiovascular diseases associated with increased oxidation of lipids and inflammation. Resistant starch and beta-carotene reduce atherosclerosis risk related to low-grade inflammation and oxidative stress in obesity. AIM: This study aimed to evaluate the benefits of a snack containing high-resistant starch and beta-carotene in improving the atherogenic index of plasma (AIP) and inflammation in obesity. METHODS: This study used a single-blinded and randomized controlled design. Fifty subjects received 42 g of snacks per day for 6 weeks, either tested snacks or standard snacks. Anthropometry, body composition, lipid profile, tumor necrosis factor-alpha (TNF-α), and oxidized low-density lipoprotein (ox-LDL) were measured before and after intervention. RESULTS: The snack containing high-resistant starch and beta-carotene significantly decreased LDL, AIP, and TNF-α (p &lt; 0.05). Positive correlations were found between AIP and triglycerides in both snacks (p &lt; 0.05), LDL or TNF-α in the standard snack (p &lt; 0.05), and TNF-α and ox-LDL in both snacks (p &lt; 0.05). A negative correlation was found between AIP and HDL in both snacks (p &lt; 0.05). CONCLUSIONS: A snack containing high-resistant starch and beta-carotene reduced AIP and inflammation by preventing LDL oxidation.

Structural and in vitro starch digestion properties of starch-fatty acid nanocomplexes: effect of chain lengths and degree of unsaturation of fatty acids.

The structural and digestion properties of starch-lipid complexes are closely related to the properties of lipids. The chain length and degree of unsaturation of fatty acids (FAs), which can affect the structural and digestion properties of starch-lipid nanocomplexes, therefore need to be examined in detail to gain a better understanding of this. In this study, the effects of chain length (10-18 carbons) and degree of unsaturation (0-2) of FA on the structural and in vitro starch digestion properties of high amylose corn starch (HAS)-FA nanocomplexes were investigated, as was the correlation between their structural alterations and digestibility. This study showed that HAS-FA nanocomplexes with 10-carbon (38.55%) and 12-carbon (44.56%) FAs displayed high-resistant starch (RS)and slowly digestible starch (SDS) content, whereas those with 18-carbon FAs with two double bonds exhibited low RS + SDS content (23.41%). The complexing index, R1047/1022 , relative crystallinity, and enthalpy change in the HAS-FA nanocomplexes also increased with the reduction in the chain length (except for 10-carbon FA) and the degree of unsaturation of FAs, whereas the equilibrium hydrolysis percentage, kinetic constant and apparent amylose content showed an opposite trend. Chain length and degree of unsaturation of FAs affected the digestibility of HAS-FA nanocomplexes. The HAS-FA nanocomplexes with 12-carbon FAs displayed high RS + SDS content with higher degrees of molecular order at long-range and short-range levels. Results provided guidelines to regulate the digestibility of starch-fatty acid nanocomplexes by varying the FA structures. © 2022 Society of Chemical Industry.

In vitro digestibility, pasting, and thermal properties of Arenga pinnata ( Wurmb. ) Merr starch citrate

This study aims to prepare citrate-esterified Arenga pinnata (Wurmb.) Merr starch (APS) with different degrees of substitution (DS [0, 0.02, 0.24, 0.40]) and evaluate in vitro digestibility, pasting, and thermal properties of citrate APS. The citrate APS surface become rougher. Citric acid modification led to significant changes in molecular and crystal structure citric acid treatment significantly reduced molecular weight of APS, and the molecular weight was decreased with increasing the DS. The citrate APS possessed a lower pasting viscosity and a higher resistant starch (RS) content. RS content of APS citrate was increased with increasing the DS, and the maximum RS content reached 74.21%. Citric acid modification improved thermal stability of the APS. These results suggested that the structural alterations might be responsible for changes of APS citrate properties and the citrate APS was an excellent potential food additive that had desirable functional properties and high RS content. Novelty impact statement The non-conventional APS was modified using citric acid. The citrate APS possessed a lower pasting viscosity and had a higher RS content, up to 74.21%. The citrate APS had a higher thermal stability.

Recent Developments in Starch Modification by Organic Acids: A Review

AbstractTreatment or processing of starch with organic acids (citric, stearic, succinic, and malic acids) can be used to obtain starch properties like low retrogradation, desirable viscosity, shear resistance, and high resistant starch. Esterification, cross linking, and hydrolysis of starch may occur after modification with organic acids (citric, succinic acid, malic acid) whereas a complex between starch and stearic acid may be formed on use of stearic acid. The conditions of reactions namely duration, starch acid concentration ratio, and temperature may influence physicochemical and structural properties of starch. Citric acid, succinic acid, stearic acid, and malic acid are regarded as "GRAS" and thus the starch citrate, starch succinate, starch stearate, and starch maleate are widely used in manufacturing of starch films, blends, nanoparticles, fat replacer, viscosity enhancer, and many other products. This review paper discusses the reaction conditions of organic acid modification of starches along with their influence on physicochemical and structural characteristics.

Replacing a part of wheat flour with starchy food containing high levels of resistant starch in noodles processing

Resistant starch has been shown to be associated with many health benefits. The study was conducted to analyze amylose and resistant starch content in selected starchy materials (black beans, red beans, green Xiem bananas, and potatoes) and investigate the influence of their flour/starch mixing ratio on the quality of noodles. The microstructure of noodles was analyzed by scanning electron microscopy. The results showed that potato starch had the highest resistant starch content (56.70%), followed by green Xiem banana flour (41.55%), black bean flour (16.51%), and red bean flour (15.55%). The raw materials with higher resistant starch also had higher amylose content. Amylose content, resistant starch content, and hardness of noodles increased when partly replacing wheat flour with the high level of RS flours/starches in the formulation. The data rank some tests revealed that formula A3 (replacing 50% of wheat flour with other starchy food containing high levels of resistant starch) was chosen due to the product containing relatively high RS content (14.78%), well structured and well accepted by panellists. The texture of the cooked noodles was assessed to be similar to that of the control sample (100% wheat flour). This study proved that it is possible to elaborate noodles to replace a part of wheat flour with starchy food containing high levels of the well-accepted formulation.

A Pilot Study to Assess Glucose, Insulin, and Incretin Responses Following Novel High Resistant Starch Rice Ingestion in Healthy Men.

IntroductionA newly developed resistant starch (RS) rice line with double mutation of starch synthase IIIa and branching enzyme IIb (ss3a/be2b) exhibits a tenfold greater percentage RS value than the wild-type rice line. Currently, the effects of cooked rice with such high RS content on secretion and action of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are unclear. Therefore, we conducted a pilot study to assess postprandial responses of GLP-1 and GIP along with glucose and insulin and also gastric emptying after ingestion of the high-RS cooked rice with ss3a/be2b in healthy subjects.MethodsIn a non-randomized crossover design, five healthy men ingested two test foods, control (low-RS) and high-RS cooked rice, with at least 1-week washout period between testing days. Plasma glucose, serum insulin, plasma total GLP-1, plasma total GIP, and also gastric emptying rate were measured after ingestion of each test food, and the incremental area under the curves (iAUC) was calculated for each biochemical parameter using the values from 0 to 180 min after ingestion.ResultsThe high-RS cooked rice ingestion tended to reduce iAUC-glucose (p = 0.06) and significantly reduced iAUC-insulin (p < 0.01) and iAUC-GLP-1 (p < 0.05) but not iAUC-GIP (p = 0.21) relative to control cooked rice ingestion. In addition, the high-RS cooked rice ingestion did not affect gastric emptying.ConclusionsThe present results indicate that the suppressive effects of the high-RS cooked rice ingestion on postprandial responses of glucose and insulin may be provided through attenuation in GLP-1 secretion along with its low digestibility into glucose. We suggest that the high-RS rice with ss3a/be2b may serve as a better carbohydrate source and also as a novel functional food for dietary interventions to improve postprandial hyperglycemia and hyperinsulinemia without both enhancing GLP-1 secretion and affecting gastric emptying in patients with diabetes.