Slowly Digestible Starch Research Articles

Effect of the Amylose Nanoscale Polymerization Index on the Digestion Kinetics and Mechanism of Recombinant Chinese Seedless Breadfruit Starch Triadic Complexes.

The demand for multicomponent foods to meet human energy and nutritional needs has been increasing; however, few studies have addressed the theoretical basis for their preparation. We investigated the effect of the nanoscale polymerization index (DPw) of amylose on the logarithm of slope plot-based kinetics and the mechanism of digestion of starch-lauric acid-β-lactoglobulin protein complexes. Amylose from each of the five Chinese seedless breadfruit species was mixed with breadfruit amylopectin with the highest resistant starch (RS) content to form starch ternary complexes with various amylose DPws. All five complexes exhibited V-type crystalline diffraction and rod-like molecular configuration. Characteristic X-ray diffraction peaks and Fourier transform-infrared spectra of the ternary complexes revealed similar molecular configurations. As the amylose DPw increased, the complexing index, relative crystallinity, short-range order, weight-average molar mass, molecular density index, gelatinization temperature, decomposition temperature, RS, slowly digestible starch (SDS), and speed rate constants at the second hydrolysis stage (k2) increased, whereas the semicrystalline lamellae thickness, mass fractal structure parameter, average characteristic crystallite unit length, radius of gyration, fractal dimension and cavities of granule surface microstructure, final viscosity, interval speed rate from SDS to RS, equilibrium concentration, and glycemic index decreased. The digestion kinetics exhibited highly significant variation according to the physiochemical properties and multiscale supramolecular structure (r > 0.99 or r < -0.99, p < 0.01). Together, these results identify amylose DPw as an important structural factor that markedly affects the kinetics and mechanism of ternary complex digestion and provide a new theoretical direction for the production of starch-based multicomponent foods.

Effect of Heat–Moisture Treatment on Crystallinity, Digestibility Properties, Bioactive Compounds, and Antioxidant Activity of Purple Rice (Oryza sativa L. indica) Flour

Purple rice flour was modified using heat–moisture treatment (HMT) in three cycles using an oven (OHMT) and autoclave (AHMT) at temperatures of 100 °C and 120 °C, and with moisture levels of 20%, 25%, and 30%. X-ray diffraction was used to analyze the changes in the molecular structure. The swelling capacity, solubility, and starch digestibility, including rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), were studied in both native and modified purple rice flour. the bioactive compounds and antioxidant activities were also evaluated. Both OHMT and AHMT resulted in a decrease in swelling capacity, solubility, and RDS, but an increase in RS and SDS values compared to the native purple rice flour. All samples showed an increase in relative crystallinity. Both treatments also had an impact on the bioactive compounds and antioxidant activities, leading to a decrease in total phenolic content, total anthocyanin content, and the scavenging activity of DPPH and ABTS radicals compared to the native purple rice flour. The findings suggest that HMT can both improve the functional properties of purple rice flour and hold potential for use in various food industries.

Physicochemical properties and in vitro digestibility of proso millet starch modified by heat-moisture treatment and annealing processing

Heat-moisture treatment (HMT) and annealing (ANN) were applied to modify the proso millet starch, and then the physicochemical properties as well as the in vitro digestion of the modified starch were investigated systematically. Results indicated that HMT and ANN did not change the typical A-type crystallinity. However, both processes cause cracks and dents on the surface of the granule. The gelatinization temperature increased while peak viscosity value, relative crystallinity and gelatinization enthalpy of proso millet starch decreased significantly after HTM and ANN. Meanwhile, a remarkable increase of the slowly digestible starch(SDS) and resistant starch(RS) content was noticed after HTM and ANN modification (the highest content of SDS and RS after HTM and ANN were 9.52 ± 0.82 %, 12.03 ± 1.36 % and 12.15 ± 0.89 %, 8.75 ± 1.63 %, respectively). Those results indicated that the ANN and HMT processes could modify the physicochemical properties and in vitro digestion of proso millet starch efficiently and showed potential application to produce healthy starch food with lower digestion.

Effects of extrusion on structural properties, physicochemical properties and in vitro starch digestibility of Tartary buckwheat flour

Tartary buckwheat is a promising pseudocereal with health benefits. However, native Tartary buckwheat flour (NTBF) cannot satisfy the specific physicochemical properties required for food processing due to its gluten-free character. This study investigated structural and physicochemical properties, the starch digestibility of Tartary buckwheat flour pregelatinized with traditional extrusion processing technology (TEPT), and improved extrusion processing technology (IEPT). TEPT had a higher destructive effect on the starch structure than IEPT. Amorphous flakes and incomplete starch granules were observed in pregelatinized Tartary buckwheat flour (PTBF). After extrusion, the relative crystallinity, endothermic enthalpy, the slowly digested starch (SDS) and resistant starch content decreased by 23.76–70.44%, 48.91–100.00%, 28.43–88.65% and 53.23–78.79%, respectively. However, the amylose molecular weight of branched starches, the degree of gelatinization (DG), the water absorption index (WAI), the starch digestibility, the rapidly digested starch content, and the glycemic index increased by 29.00–119.04%, 26.05–1279.88%, 4.2–188.70%, 9.2–19.96%, 113.04–236.25%, and 25.55–37.00%, respectively. For IEPT, crystallinity decreased with the increase in extrusion temperature and the decrease in feed moisture, whereas the DG and WAI showed a contrary trend. Compared to TEPT (5.05%), PTBF obtained with IEPT retained a higher SDS content (11.28–31.85%). Starch digestion of all samples possessed a combination of sequential and parallel digestion patterns. Correlation analysis suggested that an increase in the destructive effect on the starch structure from IEPT to TEPT was responsible for the changes in physicochemical properties and improvement of in vitro starch digestibility. This study provides a scientific basis for the quality improvement in Tartary buckwheat starchy foods following extrusion.

Effect of heat-moisture treatment on the physicochemical properties and digestibility of proso millet flour and starch

Proso millet flour (PMF) and starch (PMS) were subjected to heat-moisture treatment (HMT) at 25 % moisture content and 110 °C for 4 h. The effects of HMT on physicochemical and structural properties and in vitro digestibility of PMF and PMS were analyzed. After HMT, SEM showed aggregation and damage to the surface of starch granules, while CLSM showed proteins wrapped around the granules. The amylopectin chain length distribution (CLD) remained unchanged in PMF and PMS after HMT, indicating intact covalent bonds between glucose units. HMT decreased the swelling power, solubility, viscosity of the paste, and gelatinization enthalpy and increased the pasting temperature and gelatinization temperature of PMF and PMS. HMT changed the XRD pattern of PMF from A to A + V type starches, whereas that of PMS remained unchanged. FTIR study showed an increase in the degree of short-range molecular order of PMF and PMS after HMT. In vitro digestibility evaluation showed that the rapidly (RDS) and slowly digestible starch (SDS) contents of PMF and PMS increased, whereas the resistant starch (RS) content decreased after HMT. HMT flour and starch have suitable properties for use in a wide range of food products, from canned to frozen, as well as non-food products.

Biochemical characteristics and potential application of a thermostable starch branching enzyme from Bacillus licheniformis

Slowly digestible starch (SDS) has attracted increasing attention for its function of preventing metabolic diseases. Based on transglycosylation, starch branching enzymes (1,4-α-glucan branching enzymes, GBEs, EC 2.4.1.18) can be used to regulate the digestibility of starch. In this study, a GBE gene from Bacillus licheniformis (bl-GBE) was cloned, expressed, purified, and characterized. Sequence analysis and structural modeling showed that bl-GBE belong to the glycoside hydrolase 13 (GH13) family, with which its active site residues were conserved. The bl-GBE was highly active at 80 °C and a pH range of 7.5–9.0, and retained 90% of enzyme activity at 70 °C for 16 h. bl-GBE also showed high substrate specificity (80.88 U/mg) on potato starch. The stability and the changes of the secondary structure of bl-GBE at different temperature were determined by circular dichroism (CD) spectroscopy. The CD data showed a loss of 20% of the enzyme activity at high temperatures (80 °C), due to the decreased content of the α -helix in the secondary structure. Furthermore, potato starch treated with bl-GBE (300 U/g starch) showed remarkable increase in stability, solubility, and significant reduction viscosity. Meanwhile, the slowly digestible starch content of bl-GBE modified potato starch increased by 53.03% compared with native potato starch. Our results demonstrated the potential applications of thermophilic bl-GBE in food industries.

Morphological and physicochemical changes in the cassava (Manihot esculenta) and sweet potato (Ipomoea batata) starch modified by pyrodextrinization

In recent years, resistant starch (RS) and slowly digestible starch (SDS) have been linked to the prevention of chronic noncommunicable diseases, such as obesity and its complications. Southern Mexico has an important role in the tuber crop production of M. esculenta and I. batatas, which contain considerable amounts of starch. The aim of this study was to evaluate the morphological and physicochemical changes of M. esculenta and I. batatas after pyrodextrinization, including the production of RS and SDS. The factors used in this study were the starch/acid ratio (2.2 HCl) (80:1 and 160:1 p/v); temperature (90 °C and 110 °C) and reaction time (1 and 3 h). The highest production of RS in M. esculenta was obtained with the highest starch/acid ratio and temperature, and the lowest reaction time. For pyrodextrins, loss of crystallinity and an increase in swelling power and water absorption capacity were observed. The highest production of RS in I. batatas was obtained with the highest starch/acid ratio and reaction time, and the lowest temperature. Crystallinity and enthalpy of gelatinization decreased in modified starches. The solubility, swelling power and water absorption capacity increased in both sources.

Self-assembling soy protein fibril aggregates: Characterization and impact on in vitro digestibility of potato starch

This study is focused on the characteristics of thermally induced fibril aggregates originating from soybean protein (SPFA), and the impacts of the SPFA on digestive, structural, and physicochemical properties of potato starch (PS). The SPFA, caused by heating for various heating periods at 85 °C and low pH, displayed significantly different structural changes, morphological characteristics, and particle size distributions. The results revealed that the presence of SPFA could improve the degree of short-range order and forms more compact structure than the PScontrol. The SPFA increased thermal stability, reduced pasting viscosity, and delayed short-term retrogradation of PS. And the non-covalent interactions between PS and SPFA were enhanced under cooking conditions. The fraction of digested starch at 300 min (C300) content of the PS-SPFA complex was reduced by 8–20%, while the C300 of the PS-SPFA mixture reduced only 1–4%. The SPFA with longer thermal treatment (16, 24 h) displayed significant lower rapid digestible starch content (RDS) and higher slowly digestible starch (SDS) than those with shorter thermal treatment (2, 8 h). This study is expected to deepen the understanding of the interaction between food components, enrich the theory of protein regulation of starch digestion.

STUDY ON MODIFICATION OF YAM STARCH (Dioscorea alata L.) CREATING SLOW DIGESTING STARCH BY ACID HYDROLYSIS

This study was conducted to modify yam starch to create slowly digestible starch (SDS) by the acid method to create the highest SDS starch on the basis of evaluating the effect of citric acid concentration (15 – 45%), temperature (37.5 – 52.5oC) and hydrolysis time (1.5 – 10.5 h) was performed based on the multivariable modelby CCD method, and the starch content SDSmax was the dependent response. The results showed that the quadratic model obtained is significant (p &lt; 0.05), the reliability of the model R2 = 0.979 showed that the built regression model is suitable for the data set whether 97.9%. As a result, the highest SDS starch content is 18.052% at an acid concentration of 40,009%, a temperature of 39.962oC and a hydrolysis time of 8.933 h.Solubility increases due to temperature, swelling increases in the range temperature of 50 – 70oC and decreases from 70 – 90oC; the viscosity of starch tends to decrease after denaturation.

Association of Slowly Digestible Starch Intake with Reduction of Postprandial Glycemic Response: An Update Meta-Analysis.

Slowly digestible starch (SDS) has been shown to digest slowly throughout the entire small intestine, generating slow and prolonged release of glucose, according to the in vitro Englyst assay. The aim of this work was to conduct a meta-analysis of up-to-date evidence to evaluate the association between SDS consumption and a reduction in the postprandial glycemic response, including extended glycemic index (EGI) or glycemic profile (GP) parameters, during in vivo digestion. We searched the Web of Science, PubMed, Europe PMC, Cochrane Library, and Embase to identify related articles published up to September 2022. Human trials investigating the effect of the SDS amount on the postprandial glucose profile were estimated at the standard mean difference (SMD), with a 95% confidence interval (CI), using random effect models. The review followed the systematic reviews and meta-analyses (PRISMA) guidelines. The meta-analysis included a total of 65 participants. The results revealed that the EGI experienced a greater increase (SMD = 24.61, I2 = 79.2%, p &lt; 0.01) after SDS intake, while the GP exhibited similar trends (SMD = 29.18, I2 = 73.3%, p &lt; 0.01). High heterogeneity vanished in the subgroup and sensitivity analysis (EGI: I2 = 14.6%, p = 0.31; GP: I2 = 0.0%, p = 0.97). There was no evidence of publication bias for EGI (p = 0.41) or GP (p = 0.99).The present meta-analysis provides evidence that SDS intake is positively correlated with EGI and GP levels. The quantitative relationship of the reduction in the postprandial glycemic response and SDS consumption was used to quantify the slow digestion property on an extended time scale, and supplement the in vitro concept of SDS.

Effects of Heat-Moisture Treatment on the Digestibility and Physicochemical Properties of Waxy and Normal Potato Starches.

Heat-moisture treatment (HMT) is a safe, environmentally friendly starch modification method that reduces the digestibility of starch and changes its physicochemical properties while maintaining its granular state. Normal potato starch (NPS) and waxy potato starch (WPS) were subjected to HMT at different temperatures. Due to erosion by high-temperature water vapor, both starches developed indentations and cracks after HMT. Changes were not evident in the amylose content since the interaction between the starch molecules affected the complexation of amylose and iodine. HMT increased pasting temperature of NPS from 64.37 °C to 91.25 °C and WPS from 68.06 °C to 74.44 °C. The peak viscosity of NPS decreased from 504 BU to 105 BU and WPS decreased from 384 BU to 334 BU. The crystallinity of NPS decreased from 33.0% to 24.6% and WPS decreased from 35.4% to 29.5%. While the enthalpy values of the NPS declined from 15.74 (J/g) to 6.75 (J/g) and WPS declined from 14.68 (J/g) to 8.31 (J/g) at 120 °C. The solubility and swelling power of NPS decreased while that of WPS increased at 95 °C. Due to the lack of amylose in WPS, at the same HMT processing temperature, the reduction in peak viscosity of treated WPS compared to that of native starch was smaller than that of NPS. The resistant starch (RS) content of NPS after HMT at 120 °C was 73.0%. The slowly digestible starch (SDS) content of WPS after HMT at 110 °C was 37.6%.

BUCKWHEAT STARCH-MYRISTIC ACID COMPLEX FORMATION: EFFECT OF REACTION TEMPERATURE AND MYRISTIC ACID CONCENTRATION ON DIGESTIBILITY PROPERTIES

This study aimed to investigate the effect of different reaction conditions on the digestibility properties of buckwheat starch-myristic acid complex samples produced using different myristic acid concentrations and different reaction temperatures. Response Surface Methodology was used to investigate the effect of reaction temperature (60-90°C) and fatty acid concentrations (0.1-0.8 mmoL/g) on digestibility properties. Resistant starch (RS) contents of samples increased with an increase in reaction temperature. The reaction temperature affected the rapidly digestible starch (RDS) and slowly digestible starch (SDS) content of samples. The highest RS content (32.57%) was obtained using 0.45 mmoL/g myristic acid at 90°C. The F, p (&amp;lt;0.05), and R2 values indicated that the selected models were significant for the digestibility properties of samples. The complex formation of buckwheat starch with myristic acid seems promising to increase the RS content. Buckwheat appears to have the potential as an RS source, although the studies are quite new yet.

Heat-induced amorphous aggregates assembly of soy protein modulate in vitro digestibility of potato starch

This research focused on the characteristics of amorphous aggregates derived from soy protein (SPAA), and their effects on the structural, physicochemical, and digestive properties of potato starch (PS). The SPAA induced by different heating temperatures at pH 7.0 formed an inhomogeneous spherical structure. The presence of SPAA could improve the degree of short-range order of starch, increase thermal stability, reduce pasting viscosity and breakdown, and setback viscosity values of PS. For the PS complexed with SPAAs under simulated cooking conditions, the fraction of digested starch at 300 min (C300) decreased by 6–14 %, and rapid digestible starch content (RDS) decreased by 18–25 %, while the slowly digestible starch (SDS) and resistant starch (RS) increased by 0.4–3 % and 15–23 %, respectively. The SPAA at higher temperature treatment (SPAA130) reduced digestive rate coefficient (k) values more significantly than SPAA at a lower temperature (SPAA70, SPAA90, SPAA110). And the SPAA had no inhibitory effect on α-amylase. The results of this study would significantly contribute to expanding the theoretical information about protein regulation in starch digestion and promoting the development of healthy foods with digestion-resistant properties.

Structure, gelatinization, and digestion characteristics of starch from Chinese wild rice

ABSTRACT Two wild rice starches were isolated from Erhai in Dali, Yunnan Province (EWR) and Xinghua in Taizhou, Jiangsu Province (XWR), China, and compared with black rice (BR) starches, its structure, gelatinization and starch digestibility in vitro were studied. The results showed that the apparent amylose content of starches in EWR and XWR was 19.82% and 20.33%, respectively. The starch granules were irregular polygons and all were A-type crystals, with relative crystallinity of 25.6%~26.65%, similar short-range ordered structure and layered structure, and the thickness of the semi-crystalline layer ranged from 9.82 nm to 9.97 nm. XWR and EWR starches had exhibited the same gelatinization temperature range, enthalpy of gelatinization (ΔHgel) and swelling power, but XWR starches was higher than EWR in the gelatinization temperature and lower than EWR in the solubility. The rapidly digestible starch (RDS) content of wild rice starches in the two regions was low, only 3.63% and 37.32%, whether it was raw starches or gelatinized starches. After gelatinization, the RDS and slowly digestible starch (SDS) content were significantly increased and the resistant starch (RS) content was decreased, but the RS content was still higher than the common grains. Therefore, the wild rice starches are more suitable for processing and producing resistant starch products. Extracting starch from Chinese wild rice can provide guidance and reference for its application in edible and non-edible products, and promote the development and utilization of Chinese wild rice. Abbreviations: EWR, wild rice from Erhai in Dali, Yunnan Province; XWR, wild rice from Xinghua in Taizhou, Jiangsu Province; RDS, rapidly digestible starch; SDS, slowly digestible starch; RS resistant starch; TS, total starch; To, onset temperature of gelatinization; Tp, peak temperature of gelatinization; Tc, conclusion temperature of gelatinization; ∆Hgel, enthalpy of gelatinization.

Starches Isolated from the Pulp and Seeds of Unripe Pouteria campechiana Fruits as Potential Health‐Promoting Food Additives

AbstractThe non‐conventional starch isolated from unripe fruits is an alternative to obtain this raw material with improved or different functionality and digestibility. The starch isolated from Pouteria campechiana pulp (SIP) and seeds (SIS) of unripe fruits shows similar average granule sizes and A‐type X‐ray diffraction pattern. The digestibility characteristics are related to the hierarchical structure, since the amylopectin of the SIS sample has the highest crystallinity percentage and degree of polymerization (DP). These long amylopectin chains produce a thermally stable helical structure. Resistant starch (RS) in the SIP and SIS samples remains after cooking, and the cooked SIS show an increase in slowly digestible starch (SDS) content. In contrast, cooked SIP has an increased content of rapidly digestible starch (RDS). The SIP sample also shows interesting β‐carotene content values (15.4 µg g−1 dry starch) for the manufacture of potentially health‐promoting food additives in terms of anti‐inflammatory and antioxidant activities. The supramolecular structure–in vitro digestibility relationship of the SIS sample yields interesting results as a novel, low‐cost, and underutilized alternative starch source for the manufacture of potential health‐promoting starchy food additives.

Electron beam irradiation application for improving the multiscale structure and enhancing physicochemical and digestive properties of acetylated naked barley

The study used electron beam (EB) irradiation pretreatment to prepare acetylated (AC) naked barley starch. EB pretreatment enhanced the degree of substitution in acetylation from 0.027 to 0.109 %. The starch granules treated with EB and AC had a rough surface but maintained integrity. EB depolymerized the starch structure, providing opportunities for molecular rearrangement, thereby increasing the efficiency in the subsequent acetylation process. Therefore, EB pretreatment decreased AC starch amylose content (27.82 to 21.61 %), amylopectin molecular weight, relative crystallinity (31.04 to 26.23 %), short-range order, and increased amylose molecular weight comparing EB or AC-treated alone. These structural changes improve the properties of starch; thus, EB pretreatment reduced the thermal transition temperature, gelatinization enthalpy, pasting parameters, rapidly-digestible starch content (67.09–51.74 %), solubility, and improved content of slowly-digestible starch (23.82–36.65 %) and resistant starch (9.09–11.62 %). EB pretreatment can enhance efficiency and improve the structure and performance of acetylated modified starch.

Genotype-by-Environment Interaction Analysis of Metabolites in Pearl Millet Genotypes with High Concentrations of Slowly Digestible and Resistant Starch in Their Grains.

Genotype × environment interactions (GEIs) should play an important role in the selection of suitable germplasm in breeding programmes. We here assessed GEI effects on pearl millet (Pennisetum glaucum L.) genotypes, selected to possess a high concentration of slowly digestible starch (SDS) and resistant starch (RS) in their grains. Entries were grown in a randomized complete block design with three replications at locations in Bawku-Ghana, Sadore-Niger, Bamako-Mali, Konni-Nigeria, and Gampella-Burkina Faso across West Africa. Harvested grains from these locations were metabolomically profiled using flow injection ionization-high-resolution mass spectrometry (FIE-HRMS). A total of 3144 mass features (m/z) (1560 negative ion mode and 1584 positive ion mode) were detected, of which, 475 m/z were linked to metabolites be involved in starch, antioxidant and lipid biosynthesis, and vitamin metabolism. Combined ANOVA revealed that the GEI was significantly evident for 54 health-benefiting metabolites, many associated with sugar, especially galactose, metabolism. Additive main effects and multiplicative interaction (AMMI) analysis examined genotype variation and GEI effects, which, when combined with principal component analysis (PCA), found that m/z 171.14864 (positive ionisation, propenyl heptanoate) accounted for 89% of the GEI variation along PC1. The AMMI-based stability parameter (ASTAB), modified AMMI stability value (MASV), and modified AMMI stability index (MASI) were then applied to identify stable and high-performing genotypes for all the health-benefiting metabolites. Similarly, the best-linear-unbiased-prediction (BLUP)-based stability estimation was also performed using the harmonic mean of genotypic values (HMGV), relative performance of genotypic values (RPGV), and harmonic mean of relative performance of genotypic values (HMRPGV), to identify genotype rankings across multiple environments. The multi-trait stability index (MTSI) was calculated and found that the genotypes G1 (ICMH-177111) and G24 (ICMX-207137) were the most stable and were the best mean performers across 52 health-benefiting metabolic traits. These findings demonstrate the potential of G × E assessments on the delivery of health-benefiting metabolite-rich grains in future varieties and hybrids of pearl millet.

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.

The Effect of Soybean Peptides on Improving Quality and the ACE Inhibitory Bioactivity of Extruded Rice

It is crucial to address the dietary problems of hypertensive patients. The effect and mechanism of different contents of soybean protein on cooking quality and angiotensin-converting enzyme (ACE) inhibitory action in the extruded rice were firstly investigated. The results showed that the extruded rice with soybean protein possessed the higher taste value (90.32 ± 2.31), hardness (2.65 ± 0.01 g), and good pasting quality (p ≤ 0.05). Meanwhile, the soybean protein notably retarded the starch digestibility; the sample with 6% soybean protein showed the fewest rapidly digestible starch (RDS) content (78.82 ± 0.01 mg g−1) and the most slowly digestible starch (SDS) content (8.97 ± 0.45 mg g−1). Importantly, the ACE inhibition rate improved from 17.09 ± 0.01% to 74.02 ± 0.65% in the 6% soybean protein sample because of the production of peptides. The peptide composition of samples were compared, which showed that the effective ACE-inhibitory peptides usually contain 2~20 amino acids, and Pro, Leu, Ile, Val, Phe, and Ala were the main components. Overall, moderate soybean protein would give a good quality and lower ACE activity in extruded food.

Octenylsuccinic anhydride group distribution in esterified maize starches with different granular structure and its effect on starch digestibility

This study aimed to investigate the distribution of octenylsuccinic anhydrid (OSA) groups in different maize starch granules and its effect on starch digestibility. OSA starches with two substitution degrees (DS) about 0.02 and 0.05 were prepared. Confocal Laser Scanning Microscopy and Confocal Raman spectra showed that OSA groups distributed mainly on the granules surface at low DS of all the starches. The content of OSA groups in center area increased with the increasing DS for A-type starch, while the content of OSA groups decreased from the surface to inner at both low and high DS for B-type starch. This demonstrated that OSA reagent could travel through the granule pores and channels to arrive at the cavity in the A-type starch. However, due to a dense internal structure for B-type starch, OSA groups could graft into the granule only by penetration. Analysis of X-ray Diffraction showed that the degree of crystallinity slightly decreased as the increasing DS of OSA starch. The content of rapidly digestible (RDS) and slowly digestible starch (SDS) decreased, but that of resistant starch (RS) increased in the raw OSA starches with the increasing DS (RDS: 23.0%, RDS: 8.3%, RS: 72.3% for the raw waxy maize starch with 0.05 DS). It indicated that the hydrolysis of the OSA starches was influenced by the distribution of OSA groups.