Hylon VII Research Articles

Comparison of structural and in vitro digestive properties of autoclave-microwave treated maize starch under different retrogradation temperature conditions

Retrogradation is a critical step in the physical production of resistant starch. This study aimed to examine the effects of isothermal and temperature-cycled retrogradation on the structural, physicochemical properties, and digestibility of resistant starch type-III (RS3) under various thermal conditions. To create RS3, normal maize starch (NM) and Hylon VII (HAM) were treated by autoclave-microwave and then retrograded at isothermal (4 °C) or various temperature conditions (4/10 °C, 4/20 °C, 4/30 °C, 4/40 °C, and 4/50 °C). We found that temperature-cycled retrogradation possessed greater potential than isothermal retrogradation for producing short-range ordering and crystalline structures of RS3. Also, retrograded starch prepared via temperature cycling exhibited higher double helix content, lower amorphous content, reduced swelling power, and less amylose leaching in water. Furthermore, the starch digestibility was affected by structural alterations, which were more significant in HAM-retrograded starch. While, HAM-4-40 (39.27 %) displayed the highest level of resistant starch (RS).

Characterization of different high amylose starch granules. Part I: Multi-scale structures and relationships to thermal properties

The multi-scale structure and thermal properties of eight widely different types of high-amylose starches (HASs) having amylose contents (AC) in the range of 34.4%–97.3% originating from maize, wheat, barley, and potato were analyzed to unveil possible relationships among different levels of structures and thermal properties. The starches were found to cluster in four groups: (I) two HASs from maize, Gelose50 and Gelose80, with high gelatinization enthalpy (△H) and low onset (T0) and peak (Tp) gelatinization temperatures, (II) two HASs from potato and wheat, with medium and high △H and extremely low T0 and Tp, (III) two HASs from maize, NAFU50 and NAFU60, with medium △H and medium T0 and Tp, (IV) two HASs from maize and barley, Hylon VII and AOBS, with low △H but high T0 and Tp. The degree of molecular branching and the extent of the granule V-type crystalline polymorph were the critical factors determining their thermal properties, while botanical source and AC were not found important. HASs from wheat and barley showed relatively low lamellar and crystalline order, which was related to high content of amylopectin or AM-like chains with degree of polymerization (DP) 6–12 and long amylose chains, both of which can contribute to prevent the formation of double helices. Our data pinpoint the importance of amylopectin short chains, amylose long chains, and degree of branching on HAS starch granule structural order and thermal stability, which are potentially useful in boosting the development of HAS-based products and be beneficial for developing new HAS crops.

In vitro digestibility, glycaemic index and bile acid–binding capacity of foods containing different types of resistant starch in comparison with the commercial resistant starches

This study investigated the in vitro digestibility, glycaemic index (GI) and bile acid–binding capacity (BABC) of some potential resistant starch source food products (PRSF). Commercially available resistant starch (RS) samples, Hylon VII (RS2), Novelose 330 (RS3) and Fibersym (RS4) were also included in the study. The RS content of the PRSF used in this study was in the range of 25–77%. Standardised static in vitro digestion processes were applied, and the total digestibility, GI and BABC of the samples were determined. The digestibility of commercial RS samples was lower than the PRSF samples. No significant correlation was found between digestibility and RS or total dietary fibre (TDF) contents of the samples. A statistically significant positive correlation was obtained between GI and in vitro digestibility values. In addition, there was a statistically significant negative correlation between the GI and TDF content of the PRSF samples. In addition, it was observed that neither RS content nor RS type had a significant effect on BABC.

High Amylose Corn Starch Gels—Investigation of the Supermolecular Structure

AbstractAqueous gels based on two high amylose corn starch (HACS) genotypes with different amylose (AM) contents (HYLON V [HACS‐50] and HYLON VII [HACS‐70]) are prepared by gradation of the polymer concentration (6 and 9% w/w) and storage duration (1 and 14 days). The supermolecular structure of the wet gels is investigated by means of confocal laser scanning microscopy (CLSM), and the dried starch gel material examines crystallographically using X‐ray diffraction (XRD) and morphologically using scanning electron microscopy (SEM). In particular CLSM reveals that the gel structure shows changes with the storage time. XRD experiments reveal the existence of the B‐type crystalline structure as well as a remarkable portion of the V‐type, and higher crystallinity (Xc) is found after long‐term storage. Observation of the dried gel material's surface facilitates the assumption of a fractal‐based arrangement (structure of retrograded starch) within the starch gel network. The results are discussed closely with obtained data related to the molecular level of the gel matrix involved starch polymers, which are reported in previous publications.

Fibrous Structures from Starch and Gluten.

Starch is added to meat analogues for binding and water holding. In this study, we investigate whether starch can have an additional role as a structuring agent. Therefore, different types of starch were combined with wheat gluten at various amounts and sheared in a High Temperature Shear Cell to determine how starch influences the structuring behavior of gluten–starch blends. The starches were chosen based on their diverse amylose contents, leading to different technological properties. Remarkable differences were found between the starches investigated. The addition of Amioca starch (containing 1% amylose) had a strong negative influence on the ability of gluten to form fibers. Maize starch (25% amylose) and Hylon VII (68% amylose) formed fibrous materials up to high starch additions. The pre-gelatinizing of maize starch further increased the ability of gluten–starch mixtures to form fibrous structures. The influence of the different types of starch on the hardness, deformability, and stiffness of the sheared samples was also assessed, revealing a spectrum of achievable properties through the addition of starch. Most remarkable was the formation of a material with anisotropy in Young’s modules. This anisotropy is also found in chicken meat, but not in protein-based fibrous materials. Furthermore, it was observed that the pre-gelatinization of starch facilitated fiber formation. A similar effect of pre-gelatinizing the starch was found when using faba bean meal with added wheat gluten, where fibrous structures could even be formed in a recipe that previously failed to produce such structures without pre-treatment.

Chromatographic Study of High Amylose Corn Starch Genotypes – Investigation of Molecular Properties after Specific Enzymatic Digestion

AbstractTwo high amylose corn starches (HACS; HYLON V and HYLON VII) are dissolved completely and subjected to specific enzymatic degradation by means of different amylases (AMY). The starches are digested using α‐, β‐, and γ‐AMY (single) as well as in combination with the debranching enzyme pullulanase (PUL; α‐AMY‐PUL and β‐AMY‐PUL), and the products are characterized by means of size exclusion chromatography (SEC)‐techniques including multi angle laser light scattering‐differential refractive index detection (SEC‐MALS‐DRI) and conventional calibration‐differential refractive index detection (SEC‐cal‐DRI). Enzymolysis is resulted in largely maltose (Mal; α‐ and β‐AMY and respective combinations with PUL) or glucose (Glc; γ‐AMY; almost complete digestion) as the major fraction, but also other residual fractions of higher molar mass (MM), i.a. α‐ and β‐limit dextrins (α‐/β‐LDs). The quantity (relative portion) and quality (specific molecular properties) of the reaction products are found to be strongly dependent on both the enzymatic treatment by itself (kind of enzyme/‐combination and associated specificity of action) and the molecular composition of the initial starch (portion and specific molecular properties of the amylose [AM], intermediate [IM], and amylopectin [AP] fraction), which is further investigated in detail.

Effect of Resistant Starch Sources on the Physical Properties of Dough and on the Eating Quality and Glycemic Index of Salted Noodles.

The aim of this study was to evaluate the characteristics and eating quality of salted noodles that are incorporated with different formulations of flour. Up to 20% of wheat flour was substituted by composite flours of highly resistant starches, including heat moisture treatment corn starch (HMT-CS), high-amylose corn starch (Hylon VII), and green banana flour (GBF). The physical properties of dough, in conjunction with the eating quality and estimated glycemic index (EGI) of cooked salted noodles, were investigated in this study. The results concluded that the incorporation of GBF, HMT, and Hylon VII not only affected the water absorption and mixing tolerance of the dough, but also the maximum resistance to extension and extensibility in terms of the extensographic properties. Meanwhile, GBF, HMT, and Hylon VII incorporation significantly increased the resistant starch content and decreased the fat content of the noodle samples. The textural profile analyses of cooked salted noodles indicated that hardness, gumminess, chewiness, and shearing force increased; nevertheless, springiness declined with the increase in the proportion of flours from 10 to 20%. The sensory evaluation detected that wheat flour composited with 10% GBF and HMT flours could produce acceptable quality noodles as compared with normal typical control noodles. In the meantime, salted noodles incorporated with GBF, HMT-CS, and Hylon VII flour decreased the estimated glycemic index (EGI) dramatically. The result of this study concluded that incorporation of various sources of resistant starch flour could develop a low-GI noodle with good acceptability that may contribute to gastrointestinal health.

Mesoporous Carbons from Polysaccharides and Their Use in Li-O2 Batteries.

Previous studies have demonstrated that the mesoporosity of carbon material obtained by the Starbon® process from starch-formed by amylose and amylopectin can be tuned by controlling this ratio (the higher the amylose, the higher the mesoporosity). This study shows that starch type can also be an important parameter to control this mesoporosity. Carbons with controlled mesoporosity (Vmeso from 0.1–0.7 cm3/g) have been produced by the pre-mixing of different starches using an ionic liquid (IL) followed by a modified Starbon® process. The results show that the use of starch from corn and maize (commercially available Hylon VII with maize, respectively) is the better combination to increase the mesopore volume. Moreover, “low-cost” mesoporous carbons have been obtained by the direct carbonization of the pre-treated starch mixtures with the IL. In all cases, the IL can be recovered and reused, as demonstrated by its recycling up to three times. Furthermore, and as a comparison, chitosan has been also used as a precursor to obtain N-doped mesoporous carbons (5.5 wt% N) with moderate mesoporosity (Vmeso = 0.43 cm3/g). The different mesoporous carbons have been tested as cathode components in Li-O2 batteries and it is shown that a higher carbon mesoporosity, produced from starch precursor, or the N-doping, produced from chitosan precursor, increase the final battery cell performance (specific capacity and cycling).

Double helical order and functional properties of acid-hydrolyzed maize starches with different amylose content

Two maize starches (Normal and Hylon VII) were hydrolyzed using HCL for 15 days at room temperature. The water holding capacity -WHC and oil holding capacity- OHC were evaluated to describe the changes during the reorganization of hydrolyzed material. The structure was assessed using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). A hydrolysis degree of 20% was reached with a complete granular structure disruption. During acid hydrolysis, the rearrangement of decoupled double helices favored the order degree. The hydrolysis of the amorphous region decreased the enthalpy of gelatinization. This effect was more noticeable in the normal starch. The changes promoted during the hydrolysis favored the reorganization of the network resulting in high values in WHC and OHC for both starches. The acid-treated starches obtained could be used as fillers, employing these materials with induced crystalline regions.

In vitro digestibility characteristics of octenyl succinic acid (OSA) modified starch with different amylose content

The effect of amylose content in the in vitro digestibility of non-modified and OSA-modified corn starch was studied. Corn starches with different amylose content (waxy, normal and Hylon VII) were treated with 3% OSA solution. In vitro digestibility tests showed that OSA treatment reduced the fraction of fastly digestible starch, an effect that was more pronounced for cooked starch. The amylose content was negatively linked to the decrease of in vitro digestion. HPSEC analysis was conducted to gain insights on the effect of OSA-treatment on in vitro digestibility. The results showed an increase of the molecular weight of starch chains. Besides, the molecular weight increase was similar for amylose and amylopectin fractions. This suggests that OSA could be acting as a cross-linking agent between starch chains, reducing the susceptibility to amylolysis. Overall, OSA treatment induced the formation of more complex starch chains, offering more resistance for amylolytic reactions.

Effect of amylose content in morphological, functional and emulsification properties of OSA modified corn starch

Octenyl succinic starch esters were prepared from three corn starches with different amylose content; namely, waxy (5.43%), normal (25.16%) and Hylon VII (65.84%). The degree of substitution varies from 0.0103 for waxy starch to 0.0125 for Hylon VII, meaning that the degree of substitution is positively correlated with the amylose content. Scanning electron microscopy images showed that the esterification reaction affected only the granule surface while leaving the integrity of the granules. Solubility and water retention capacity were increased with the OSA modification, with the effect more pronounced for higher amylose contents. X-ray analysis revealed that the crystallinity type was not affected by esterification. FTIR analysis corroborated the changes in the hydrated and ordered structures of starch granules. Emulsification tests showed that octenyl succinic starch ester was an effective emulsifier for stabilization of oil-in-water emulsions. In particular waxy and Hylon VII starches induced high stabilization degrees as revealed by long-term stability of oil-in-water emulsions.

Prebiotics, Probiotics, and Acetate Supplementation Prevent Hypertension in a Model of Obstructive Sleep Apnea.

Disruption of the gut microbiota, termed gut dysbiosis, has been described in animal models of hypertension and hypertensive patients. We have shown that gut dysbiosis plays a causal role in the development of hypertension in a rat model of obstructive sleep apnea (OSA). Functional analysis of the dysbiotic microbiota in OSA demonstrates a loss of short chain fatty acid-producing bacteria. However, measurements of short chain fatty acid concentrations and testing of their role in blood pressure regulation are lacking. We hypothesized that reduced short chain fatty acids in the gut are responsible for OSA-induced hypertension. OSA significantly increased systolic blood pressure at 7 and 14 days ( P<0.05), an effect that was abolished by the probiotic Clostridium butyricum or the prebiotic Hylon VII. The 16S rRNA analysis identified several short chain fatty acid-producing bacteria that were significantly increased by Cbutyricum and Hylon treatment. Acetate concentration in the cecum was decreased by 48% after OSA ( P<0.05), an effect that was prevented by Cbutyricum and Hylon. Cbutyricum and Hylon reduced OSA-induced dysbiosis, epithelial goblet cell loss, mucus barrier thinning, and activation of brain microglia ( P<0.05 for each). To examine the role of acetate in OSA-induced hypertension, we chronically infused acetate into the cecum during 2 weeks of sham or OSA. Restoring cecal acetate concentration prevented OSA-induced gut inflammation and hypertension ( P<0.05). These studies identify acetate as a key player in OSA-induced hypertension. We demonstrate that various methods to increase cecal acetate concentrations are protective from the adverse effects of OSA on the microbiota, gut, brain, and blood pressure.

Effect of high-amylose corn starch addition on canning of yellow alkaline noodle composed of wheat flour and microbial transglutaminase: Optimization by RSM.

Mixture experiment was applied to optimize the canned cross‐linked high‐amylose starch yellow alkaline noodle formula. Processing factors of canned yellow alkaline noodle (YAN) cross‐linked by MTGase at different levels of Hylon VII were surveyed. The factors were wheat flour, Hylon VII starch (HAS) as a high‐amylose starch, and water in the mixture to achieve reduction in cooking loss, water uptake, swelling index, and thickness. Due to the effect of retort processing on YAN, pH, color, and texture were also examined. Analysis of variance showed that the linear mixture had a significant effect on the noodle properties. Optimum conditions were as follows: wheat flour of 75 g, HAS of 15 g, and water 67 ml. Results showed the suitable effect of Hylon in improving texture of canned YAN as well as high gel strength, neutral pH, lowest cooking loss, water uptake, swelling index, and color after retort processing. Therefore, high‐amylose decreased swelling of starch, cooking yield, and improved hardness which obtain a strong gel and better stability in canned noodle. The pH fall and the attainment of yellow color in the YAN containing Hylon can be explained by the availability of two important amino acids, lysine and glutamine which were involved in both cross‐linking reactions. The synergistic effect of low amount of flour and Hylon produced more tensile and hardness properties in canned noodle. Overall, the canned YAN prepared by adding Hylon developed the stronger gel which can withstand at high thermal retort processing and finally improve the shelf life of the final product.

Modelling the Effects of Debranching and Microwave Irradiation Treatments on the Properties of High Amylose Corn Starch by Using Response Surface Methodology

Response surface methodology was applied to determine the effects of pullulanase debranching, microwave irradiation time (2–4 min) and power (20–100%) on resistant starch (RS) formation and in-vitro glycemic index (GI) values in high amylose corn starch, Hylon VII. Starch:water (1:10) suspensions were cooked and autoclaved, debranched with pullulanase (1000 PUN/g; 1500 U/kg starch) at 60 °C and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. In order to describe the relationship between the dependent and independent variables (microwave power and irradiation time), the response values were fitted by first order polynomial regression models. Significance analysis showed that microwave irradiation time had significant effect on RS content and GI value of the samples treated with one cycle of microwave-storing prior to freeze-drying. Microwave power had significant factor on the GI value of the samples that were oven-dried after one cycle of microwave-storing. Solubility and water binding capacity values of all heat treated samples were higher than those of native starch. On the other hand, RVA viscosity values were lower than native starch for oven-dried samples. Water binding capacity, solubility and final viscosity values of the freeze-dried samples were higher than those of oven-dried ones.

Effect of Acetylation and Beta‐Amylase Treatment on Complexation of Debranched Starch with Naringenin

Starch inclusion complexation has been shown to improve solubility of water insoluble molecules. Potato starch and Hylon VII are acetylated at two levels and then debranched alone or combined with β‐amylase hydrolysis, and its complexes with naringenin are prepared in aqueous conditions and characterized in this study. Both soluble and insoluble complexes are formed with the soluble complex present in the supernatant and the insoluble complex as the precipitate after centrifugation. The recovery of the soluble complexes and the naringenin content increased when starch is acetylated, and further increased when the β‐amylase treatment is included. The naringenin contents in both complexes from Hylon VII are significantly greater than those from potato starch regardless of treatments. The insoluble complexes comprise a greater naringenin content than the soluble counterparts for both starches. FTIR spectra and thermal properties by differential scanning calorimetry confirm the molecular interaction between starch and naringenin for both complexes. This work is the first to demonstrate that starch derivatives form complexes with naringenin, and both acetylation and the beta‐amylase treatment improve their complexation.

Effect of drying method and hydrothermal treatment of pregelatinized Hylon VII starch on resistant starch content

The effect of pregelatinization and drying method in resistant starch (RS) content of high amylose starch (Hylon VII, 70% amylose content) was studied. Starch was subjected to autoclaving pre-gelatinization (40% starch suspension w/w, 121 °C) for 30 min. Oven-drying (OD) at 40 °C for 24 h and freezing-drying (FD) methods were used. Subsequently, hydrothermal treatment (HT) with 40% water content at 100 °C for 3, 12 and 24 h was applied to dried samples. Pre-gelatinization decreased the RS content by about 25% with respect to the Hylon VII starch. The drying method affected the RS content, with OD increasing and FD decreasing the RS content. HT time affected positively the RS content for OD starch, whilst the opposite effect was obtained for FD starch. XRD analysis revealed that B-type crystallinity of native starch was modified by drying and HT. Weak linear correlation (R2 = 0.69) between RS content and relative crystallinity was found. However, strong exponential correlation (R2 = 0.96) between RS content and short-range ordering quantified by FTIR measurements were found. This suggests that RS is close related to formation of double-helix and amylose-lipid complex (evidenced by the XRD peak at 2θ = 20°) during drying and heat treatment of starch.

The effect of high hydrostatic pressure treatment on the molecular structure of starches with different amylose content

The effect of high hydrostatic pressure processing (650MPa/9min) on molecular mass distribution, and hydrodynamic and structural parameters of amylose (maize, sorghum, Hylon VII) and amylopectin (waxy maize, amaranth) starches was studied. The starches were characterized by high-performance size-exclusion chromatography (HPSEC) equipped with static light scattering and refractive index detectors and by Fourier Transform Infrared (FTIR) spectroscopy. Significant changes were observed in molecular mass distribution of pressurized waxy maize starch. Changes in branches/branch frequency, intrinsic viscosity, and radius of gyration were observed for all treated starches. The combination of SEC and FTIR data showed that α-1,6-glycosidic bonds are more frequently split in pressurized amaranth, Hylon VII, and waxy maize starch, while in sorghum and maize starches, the α-1,4 bonds are most commonly split. Our results show that the structural changes found for pressurized starches were more strongly determined by the starch origin than by the processing applied.

Effects of starch composition and type of non-solvent on the formation of starch nanoparticles and improvement of curcumin stability in aqueous media

In this study, we evaluated the effects of amylopectin/amylose ratio and non-solvent type on starch nanoparticle formation including the average particle size, polydispersity index, size distribution, and nanoparticle morphology using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The most uniform particles were obtained from normal corn starch with ethanol. The average particle size was 98.8 ± 1.8 nm using DLS while combination of size distribution study and SEM images showed that particle size ranged between 60 and 90 nm. A bimodal distribution was observed with two defined groups of nanoparticles when waxy corn starch (Amioca) was nanoparticulated with ethanol. SEM images of freeze dried samples and DLS size distribution curves of fresh samples showed that high amylose starch including Hylon V and Hylon VII gave uniform, spherical and small nanoparticles in the size range of 20–60 and 15–50 nm, respectively. The smallest nanoparticles were fabricated by precipitation with methanol, followed by ethanol and the largest nanoparticles were formed using acetone. Re-dispersion of nanoparticles was good when nanoparticles were fabricated using ethanol and acetone especially for Amioca, whereas redispersion of samples in aqueous PBS solution, precipitated using methanol was difficult especially in the case of Hylon VII. Stability of curcumin in the presence of 1 mg/ml native starch nanoparticles was much higher (83.7 ± 3.1%) than curcumin in phosphate buffered saline at pH 7.0 (5.5 ± 1.5%) over 10 days at ambient temperature. Interaction between iodine-potassium iodide solution and starch nanoparticles showed that the helical structures of amylose and amylopectin molecules remain in the nanoparticles and curcumin may interact with these helical structures giving it the stability which is not observed in water.

An innovative approach for significantly increasing enzyme resistant starch type 3 content in high amylose starches by using extrusion cooking

In this study effects of extrusion cooking on enzyme resistant starch (RS) formation in high amylose corn starches (Hylon V and VII) and the functional properties of RS preparations were investigated. Native starches were extruded at 50, 60, 70% feed moisture contents, at constant screw speed (100 rpm) and barrel temperature (140 °C). Among these samples, the highest RS contents were observed at 60% feed moisture. Therefore, feed moisture in the second and third extrusion cycles was set at 60%. There were significant increases in RS contents of both Hylon V and Hylon VII after the second extrusion cycle (p < 0.05). After the third extrusion, the RS levels reached to 40.0 and 45.1% for Hylon V and Hylon VII, respectively. Substantial loss of birefringence in these samples indicated that the increases in RS were mainly due to RS3 formation. The RS samples produced by extrusion did not have high emulsion capacity, but the ones produced from Hylon VII had high emulsion stability. Although, decreases in L* and increases in b* values of extruded samples were significant as compared to respective native starches, the changes were not substantial. Therefore, their incorporation is not expected to cause major changes in the colour of end-products.

Optimization of resistant starch formation from high amylose corn starch by microwave irradiation treatments and characterization of starch preparations

The effects of microwave irradiation on resistant starch (RS) formation and functional properties in high-amylose corn starch, Hylon VII, by applying microwave-storing cycles and drying processes were investigated. The Response Surface Methodology (RSM) was used to optimize the reaction conditions, microwave time (2–4min) and power (20–100%), for RS formation. The starch:water (1:10) mixtures were cooked and autoclaved and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. The RS contents of the samples increased with increasing microwave-storing cycle. The highest RS (43.4%) was obtained by oven drying after 3 cycles of microwave treatment at 20% power for 2min. The F, p (<0.05) and R2 values indicated that the selected models were consistent. Linear equations were obtained for oven-dried samples applied by 1 and 3 cycles of microwave with regression coefficients of 0.65 and 0.62, respectively. Quadratic equation was obtained for freeze-dried samples applied by 3 cycles of microwave with a regression coefficient of 0.83. The solubility, water binding capacity (WBC) and RVA viscosity values of the microwave applied samples were higher than those of native Hylon VII. The WBC and viscosity values of the freeze-dried samples were higher than those of the oven-dried ones.