Understanding how the aggregation structure of starch affects its gastrointestinal digestion rate and extent

Insight into the nutritional, physicochemical, functional, antioxidative properties and in vitro gastrointestinal digestibility of selected Thai rice: Comparative and multivariate studies

Nutritional, physicochemical, functional, antioxidative and digestion properties of brown and white rice flours from four Thai rice varieties (Luangpatue, upland rice, RD43, and Hommali) were investigated and compared. Due to differences in grain color, the color parameters of flours varied significantly. Protein, fat, ash, carbohydrate, and moisture content, total dietary fiber, and calories of these rice flours were 6.94-10.21%, 1.68-3.16%. 0.554-1.442%, 71.20-79.68%, 9.79-10.53%, 1.07-3.64%, and 350.82-362.73 kcal/100g, respectively. RD43 brown rice (18.4%) and Luangpatue white rice (26.5%) respectively exhibited the lowest and highest amylose content. Luangpatue rice flours also showed higher swelling power, setback value, final viscosity, and thermal properties than other varieties. The variations in hydration properties and oil absorption index were noticeable among these rice flours. In addition, the highest level of total phenolic content and antioxidant activity led to the lowest estimated glycemic index (eGI = 62.92) found in upland brown rice. It was confirmed by the multivariate analysis results. This study reported the diverse physicochemical properties and composition-property relationships of two kinds of flours from four rice varieties collected from Thailand for the first time. It exhibited possible capabilities for the development of various rice-based products that promote health based on their characteristics on industrial scale.

The multi-scale structures and in vitro digestibility of starches with different crystalline types induced by dielectric barrier discharge plasma

The effects of plasma treatment on multi-scale structures and in vitro digestibility of starches isolated from Tartary buckwheat (TBS), potato (PTS), and pea (PS), were investigated. The results from SEM and CLSM showed that plasma treatment resulted in the extension of pores from the starch hilum to the surface. The XRD and 13C CP/MAS NMR spectra demonstrated that the crystalline type of three starches was not changed by plasma treatment, while the RC and double helix content of TBS increased. Besides, the single helix content and the proportion of amorphous phase decreased following the treatment, which was consistent with the result of SAXS. However, the PTS and PS showed the opposite results by plasma treatment. In addition, the modification significantly changed the molecular weight (Mw) and chain length distribution of all the starches, among which the Mw of PTS fell drastically from 2.45 × 107 g/mol to 1.74 × 107 g/mol. The in vitro digestibility of starches increased significantly when treated with plasma, in which TBS exhibited the biggest increase for its inside-out and side-by-side digestion manners. Therefore, plasma treatment led to different alteration trends for multi-scale structures with quite various change extent for in vitro digestibility about different crystalline starches.

Starch granular size and multi-scale structure determine population patterns in bivariate flow cytometry sorting

Bivariate flow cytometry (FC) sorting with forward scatter (FSC) and side scatter (SSC) is a recently established novel technique to separate starch granules. However, the forming mechanism of starch FC-dependent population patterns (i.e. the number of subgroups (NS) and FSC/SSC-dependent distribution patterns) remain partly elusive. For this, the correlation of granular size and multi-scale structure of native starches and FC-dependent population patterns was investigated through employing a wide range of native starches originating from different species involving cereal-, pulse-, and tuber crops. Results showed NS was pertinent with particle size, amylose content (AC), amylopectin chains length distribution, lamellar structure, short-range ordered structure. The distinct NS was determined by impacts of native starch FSC / SSC-dependent distribution patterns. Specifically, starch granular size significantly correlated with both FSC and SSC-dependent distribution patterns. The proportion of chains with DP 6-12 was the intra-molecular decisive factor to influence short-range ordered structure, finally leading to FSC-dependent distribution patterns. By contrast, AC was another intra-molecular index to determine SSC-dependent distribution patterns through affecting lamellar structure and short-range ordered structure.

Structure-digestibility relationships in the effect of fucoidan on A- and B-wheat starch

Fucoidans (FC) have a variety of biological activities, and it can also affect the functionality and nutritional characteristics of starch-based food products. However, there are few studies on the structural and digestive properties of starch - fucoidans blends. The effect of FC at different concentrations (0, 0.6 %, 0.8 %, 1.0 %, w/v) on the structural properties and digestibility properties of A-type wheat starch (AS) and B-type wheat starch (BS) subjected to autoclave treatment were investigated. The results show that compared with native wheat starch, AS with FC displayed higher crystallinity as well as the structural ordering, but the crystallinity and degree of order of BS with FC decreased, which was proposed due to AS interact with FC in crystalline region but BS reacts with FC in the amorphous region. With the interaction of FC with AS and BS, granules compactness of AS and BS were enhanced. The addition of FC delayed digestion in vitro of AS and BS, the rapidly digestible starch content was obviously lower than native one, and the proportion of slowly digestible starch raise markedly. This study might broaden the recognition of wheat starch with different proportion of AS and BS, and provide a theoretical basis for the potential utilization of FC in carbohydrate based food industry.

High-amylose starch: Structure, functionality and applications

Starch with a high amylose (AM) content (high AM starch, HAS) has attracted increasing research attention due to its industrial application potential, such as functional foods and biodegradable packaging. In the past two decades, HAS structure, functionality, and applications have been the research hotspots. However, a review that comprehensively summarizes these areas is lacking, making it difficult for interested readers to keep track of past and recent advances. In this review, we highlight studies that benefited from rapidly developing techniques, and systematically review the structure, functionality, and applications of HAS. We particularly emphasize the relationships between HAS molecular structure and physicochemical properties.

Effect of the starch structure fermented by Lactobacillus plantarum LB-1 and yeast on rheological and thermomechanical characteristics of dough

This study focused on exploring the structural variations of starch co-fermented by Lactobacillus plantarum LB-1 and yeast (Saccharomyces cerevisiae), and the relationship between fermented starch structure and dough characteristics. Co-fermentation resulted in the increased short chain content and crystallinity (32.07%) of starch with lower molecular weight. A higher content of fingerprint A-chains of amylopectin and fingerprint B-chains of α, β-limited dextrin in the co-fermented starch endowed dough with excellent anti-retrogradation ability. Moreover, the co-fermented starch with higher swelling power (9.44 g/g) and solubility (20.40%) had a rough and irregular structure and many gaps in the appearance, which were conducive to binding water, thus promoting high dough elasticity and strength. These results extended the knowledge of starch structure-property relationship under the microbial activities, which may be beneficial to promote better flour products.

A review of wheat starch analyses: Methods, techniques, structure and function

Wheat starch has received much attention as an important source of dietary energy for humans, an interesting carbohydrate and a polymeric material. The understanding of the structure and function of wheat starch has always been accompanied by newer technological tools. On the one hand, the general knowledge of wheat starch is constantly being enriched. On the other hand, an increasing number of studies are trying to add new insights to what is already known from two frontier perspectives, namely, wheat starch supramolecular structures and wheat starch fine structures (CLDs). This review describes the structure and function of wheat starch from the perspective of wheat starch analysis techniques (instruments).

Characterized Polysaccharides from Green Tea Inhibited Starch Hydrolysis and Glucose Intestinal Uptake by Inducing Microstructural Changes of Wheat Starch

The purpose of the current study was to investigate the effect of green tea ethanol extract (GTE) and polysaccharide fractions from green tea (PFGs) on the hydrolysis of wheat starch, microstructural changes, and intestinal transport of glucose. The amount of resistant starch (RS) was significantly lowered in the water-soluble polysaccharide (WSP), water-soluble polysaccharide-pectinase (WSP-P), and water-insoluble polysaccharide-alkali soluble (WISP-Alk-Soluble; p < 0.05). The microstructures of gelatinized wheat starch granules with WSP, WSP-P, and WISP-Alk-Soluble were spherical with small cracks. The amount of intestinal transported glucose from digested wheat starch was 2.12-3.50 times lower than the control group. The results from the current study suggest that water- and alkali-soluble PFGs could be potential ingredients to lower starch hydrolysis as well as to control the postprandial blood glucose level when foods that contain starch are consumed.

Ferulic acid grafted self-assembled fructo-oligosaccharide micro particle for targeted delivery to colon

Colorectal cancer is the third most commonly occurring malignancy and is ranked second among the leading cause of cancer death globally. The colorectal cancer is attributed to the life style and poor dietary habits. Ferulic acid is known to have anti-cancer activity, anti-oxidant activity and also known to be less toxic to normal cells under high doses. The purpose of this research is to develop an oral dietary intervention by grafting ferulic acid to fructo oligosaccharide and there by self-assembling them in to microparticles for targeted delivery to colon. The microparticle is characterized by using Solid state NMR and FTIR. Their morphological features were studied using SEM, XRD and particle size analyzer. The stability of the microparticle under simulated gastric and intestinal digestion were investigated. The physico-chemical characteristics of the microparticle was investigated by thermogravimetric analysis and by differential scanning calorimetry. Finally the antioxidant activity and anti-cancer activity of the microparticles were investigated in-vitro.

Effect of Controlled Hydrothermal Treatments on Mung Bean Starch Structure and Its Relationship with Digestibility

The changes in structure and digestion properties of mung bean starch due to hydrothermal treatment at various controlled temperatures were investigated. Results showed the increase in onset temperature (T_o) from 66.33 °C to 76.69 °C and decrease in enthalpies (∆H_g and ∆H_r) until the starch was completely gelatinized. The degree of molecular order (DMO) and degree of double helix (DDH) were significantly (p < 0.05) reduced from 1.35 to 1.01 and 1.38 to 0.98 respectively. X-ray diffraction (XRD) indicated the consecutive decrease in relative crystallinity (RC) while RVA analysis showed that peak and final viscosities were decreased significantly (p < 0.05). However, digestion kinetics indicated that degree of gelatinization increased the access of enzymes. As starch was partially gelatinized it yielded significantly lower glycemic index but no significant (p > 0.05) change in starch digestibility was observed after 70 °C. Hence, 70 °C can be considered as the critical hydrothermal treatment temperature in mung bean starch. Pearson's correlation analysis indicated that controlled hydrothermal treatment had negative effect on the DMO, DDH, RC and the granular damage increased vulnerability of mung bean starch to digestion. These findings gave insight into sequential changes in the structure and digestibility occurring during gelatinization process due to hydrothermal treatment. Controlled gelatinization in mung beans at 70 °C is useful and must be employed to produce the foods with lower starch digestibility.

The multi-scale structure, thermal and digestion properties of mung bean starch

Identification and selection one special variety mung bean for lower GI food is very useful, however, the fundamental study for mung bean starch is still insufficient to meet its demand. In this study, four varieties of mostly planted mung bean in China were selected as model materials. The multi-scale structure of mung bean starch was characterized by SEC, HPAEC, XRD, SAXS, and SEM. SEC and HPAEC give the amylose contents, amylose and amylopectin fine structure of mung bean starch. Mung bean starch from XRD spectrum display C_A type semi crystallinity. The crystalline lamellar thickness from SAXS curves were 7.34-7.60 nm. DSC indicated that the peak gelatinization temperature is at 67 °C-68 °C. Resistant starch in mung bean disappears rapidly after cooking, although the amount of slowly digested starch was still more than half of the total starch. Since the gene backgrounds of the mung bean starch samples are very close, there was no obvious difference in their molecular and aggregated state structure, and the digestion properties were similar, too. Unique SEC and HPAEC profiles of starch chain length distribution can be utilized to help find more genetic resources and cultivate variety to meet the needs for starch applications.

In Vitro Digestibility of Nanoporous Wheat Starch Aerogels

This study reports the in vitro digestibility of starch aerogels for the first time. The relative crystallinities of the wheat starch aerogels (WSAs) produced at gelatinization temperatures of 120 °C (WSA-120C), 130 °C (WSA-130C), and 120 °C with the addition of sodium metaphosphate (STMP) (WSA-STMP) and xerogel were similar. However, WSA-120C showed the highest amylose-lipid complex content. The addition of STMP created some cross-linked starch with a phosphorus content of 0.023%. Resistant starch (RS) contents of WSA-STMP (33.5%) and xerogel (26.9%) were higher than the other samples when they were uncooked prior to digestion. Nevertheless, the RS contents of WSA-STMP and xerogel decreased drastically with cooking. RS contents of WSA-120C and WSA-130C were stable with cooking and provided 4.5- and 3.0-fold increases in the RS content, respectively. WSA is a promising functional food ingredient with a high RS content, even after cooking.

Insights into the structural and physicochemical properties of small granular starches from two hydrophyte duckweeds, Spirodela oligorrhiza and Lemna minor

The structure and physicochemical properties of starches from two hydrophyte duckweeds, Spirodela oligorrhiza and Lemna minor, were investigated and compared in this study. The amylose content and average size of starches were determined to be 20.85%, 4.70 μm and 27.77%, 6.17 μm for Spirodela oligorrhiza and Lemna minor, respectively. The average chain length of two duckweed starches was measured to be around DP 28. The chain length distribution was observed to be greatly different from other reported starches for the high proportion of long chains (DP ≥ 37) over 50%. Wide-angle X-ray diffraction profiles of the two starch samples displayed typical B-type diffraction pattern. The gelatinization enthalpy-changes (ΔH_gel) of two starch samples was about 10.40 J/g for two duckweed starches. The present results suggested the potential utilization of small granular starches from duckweed in functional foods and dietary supplement products.

Characterization of multi-scale structure and thermal properties of Indica rice starch with different amylose contents

Fully understanding the relationship between multi-scale structure and thermal properties of rice starch is important for starch-based food processing.