Evaluation studies on effects of pectin with different concentrations on the pasting, rheological and digestibility properties of corn starch

Effect of annealing using plasma-activated water on the structure and properties of wheat flour

In this study, wheat flour (WF) was modified by annealing (ANN) using plasma-activated water (PAW) for the first time. Compared with WF and DW-WF, the results of scanning electron microscopy (SEM) and particle-size analysis showed that the granule structure of wheat starch in PAW-WF was slightly damaged, and the particle size of PAW-WF was significantly reduced. The results of X-ray diffraction and Fourier transforming infrared spectroscopy indicated that PAW-ANN could reduce the long-range and short-range order degrees of wheat starch and change the secondary structure of the protein in WF, in which the content of random coils and α-helices was significantly increased. In addition, the analysis of solubility, viscosity, and dynamic rheological properties showed that PAW-ANN improved the solubility and gel properties of WF and decreased its viscosity properties and short-term regeneration. PAW-ANN, as a green modification technology, has the potential for further application in WF modification, as well as in the production of flour products.

The improvement of texture properties and storage stability for kappa carrageenan in developing vegan gummy candies

BACKGROUND

As plant-based foods have become more mainstream in recent years, carrageenan has been used to replace animal-derived gelatin in confectionery products. However, texture defects and water seepage during storage limit the development of kappa carrageenan (KC) gummy candies.

RESULTS

This study evaluated the effects of hydrocolloids on the texture properties and storage stability of KC gummy candies. The results showed that 4 g kg^-1 carboxymethylcellulose (CMC) composited with 20 g kg^-1 KC formed a flexible gummy candy with low fragility and limited water seepage during storage. Further investigation revealed that 4 g kg^-1 CMC promoted side-by-side intermolecular aggregation of KC helices through hydrogen bonding, which stabilized a denser network structure compared to the pure KC hydrogel. However, high CMC proportions (8-12 g kg^-1 ) led to electrostatic repulsion that dominated in the system, inhibiting the gel-forming process and thus resulting in a weak gel structure with accelerated syneresis.

CONCLUSION

This study found that 4 g kg^-1 CMC was able to improve the flexibility and decrease unacceptable fragility of KC gummy candies, with water seepage decreased during storage significantly. It provided preliminary evidence for utilizing hydrocolloids to adjust texture and control water migration in KC gels, and has potential to promote wide development of vegan gummy candies. © 2021 Society of Chemical Industry.

Unraveling the impact of viscosity and starch type on the in vitro starch digestibility of different gels

Starch is one of the most important carbohydrates that is present in many foods. Gelatinization is an important property of starch, associated with physical changes that promote an increase in viscosity. The objective of this research was to understand how the viscosity of starch gels affects their hydrolysis and whether that effect was dependent on the type of starch. Different gels (corn, wheat, and rice) with variable or constant viscosity were analyzed using diverse methodologies to determine the changes in the pasting behavior. A rapid force analyzer, a vibration viscometer and a rheometer were used to differentiate the gels based on the starch source and concentration. At a fixed starch concentration, corn gel displayed the highest viscosity, slowing the enzymatic starch hydrolysis. The higher viscosity of those gels prepared with a fixed starch concentration significantly enhanced the slowly digestible starch (SDS) and reduced the kinetic constant (k). Nevertheless, gels with constant viscosity (550 mPa s) showed comparable hydrolysis kinetics, obtaining similar SDS, total hydrolyzed starch and k. The correlation matrix confirmed the relationship between k and gel viscosity (r = -0.82), gelatinization rate (α-slope) (r = -0.87), breakdown (r = -0.84) and elastic modulus (G' 37 °C) (r = -0.73). Therefore, these parameters could be used as predictors of the hydrolysis performance of starch gels as well as in reverse engineering for the design of healthy foods.

Mechanochemical effects on the structural properties of wheat starch during vibration ball milling of wheat endosperm

Pure wheat endosperm was fully ground in a vibratory ball mill and structural changes in wheat starch were measured to assess the effect of mechanochemical action during the grinding process. Vibratory ball milling changed the endosperm granule size to ~30 μm (D50). There was a significant increase in damaged starch content, and this was positively correlated with the grinding time. The relative crystallinity of starch decreased by 5% after milling 105 min, and the short-range order decreased. The damaged structure of amylopectin starch decreased with milling time, as detected macroscopically by the peak viscosity and final viscosity of milling samples. Overall, the in vitro digestion results showed that mechanical modification caused irregular defects inside wheat starch crystals, increased the sensitivity of wheat starch to enzymes, enhanced the hydrolysis rate three-fold, and increased the maximum starch hydrolysis by 50%. Mechanochemistry effects was used to analyze the quality changes in wheat milling.

Colour, composition, digestibility, functionality and pasting properties of diverse kidney beans (Phaseolus vulgaris) flours

The present work evaluated nine diverse kidney bean accessions for colour, composition, digestibility, protein profile, starch crystallinity, techno-functional properties, pasting properties and microstructure with the objective of identifying key attributes affecting their digestibility and functionality. The accessions exhibited dry matter digestibility, resistant starch (RS) content, water absorption capacity, fat absorption capacity, emulsifying activity index (EAI), foaming capacity (FC) and foam stability (FS) of 14.6–47.2%, 32.0–50.5%, 1.7–2.7 g/g, 1.4–1.7 g/g, 50.1–70.1 m²/g, 70.8–98.3% and 82.4–91.3%, respectively. Starch-lipid complexes (SLC), proteins and non-starch carbohydrates contributed to lower starch and dry matter-digestibility. Principal component analysis revealed positive relation of emulsification, foaming and water absorption capacity with proteins, starch, RS and ash-content while negative with crystallinity and amount of lipids, non-starch carbohydrates and digestible starch. Hydration ability of proteins promoted foaming whereas flour with lower vicilins level was less surface active and exhibited the lowest EAI, FC and FS. Pasting temperature related positively with SLC, while average starch granule size was in strong positive relationship with RS content, peak viscosity and breakdown viscosity. The results could be useful for enhanced utilization of kidney beans in different foods.

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Diverse bean flours were evaluated for digestibility and techno-functional properties.

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Starch-lipid complexes, proteins and non-starch components reduced digestibility.

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Protein hydration and vicilins contributed to foaming properties.

Green preparation of holocellulose nanocrystals from burdock and their inhibitory effects against α-amylase and α-glucosidase

In this work, holocellulose nanocrystals (hCNCs) were isolated from burdock insoluble dietary fiber (IDF) by enzymatic hydrolysis and ultrasonic treatment and their inhibitory effects against α-amylase and α-glucosidase were investigated. The hydrodynamic diameter of hCNCs decreased from about 600 to 200 nm with increasing sonication time, accompanied by an improvement in cellulose and glucose contents. Steady-state fluorescence studies suggested that static complexes were formed between hCNCs and α-amylase or α-glucosidase via a spontaneous and endothermic approach, which was driven by both hydrophobic interactions and hydrogen bonding. The median inhibitory concentration (IC₅₀) values of hCNCs against the tested enzymes were positively correlated with their size, and non-competitive and mixed types of inhibition were detected using the Lineweaver-Burk plots. During the simulated digestion, the inclusion of burdock hCNCs obviously retarded the starch hydrolysis in both dose- and size-dependent manners, suggesting their potential in blocking the postprandial serum glucose upsurge.

Understanding relations between rheology, tribology, and sensory perception of modified texture foods

The aim of this work was to examine relations between instrumental and sensory parameters in a texture modified food matrix, with and without saliva. Nine pureed carrot samples (eight thickened and a control) were developed with starch (0.4 and 0.8% wt/wt), xanthan (0.2 and 0.4% wt/wt) or starch-xanthan blends that met International Dysphagia Diet Standardisation Initiative (IDDSI) Level 4 guidelines using fork and spoon tests. Rheological and tribological tests were conducted on the food and simulated bolus prepared by adding fresh stimulated saliva to the food (1:5, saliva:food) to mimic oral processing. Perceived sensory properties were identified using a temporal dominance of sensations (TDS) test (n = 16) where panelists were given a list of nine attributes. The area under the curve was extracted from TDS curves for each attribute/sample and this was correlated with rheological (viscosity at 10 s^-1 , G', G″, and tan δ at 1 Hz) and tribological (friction coefficient in three regimes) data. The viscosity of the control sample decreased after adding hydrocolloids (except Starch_0.8%) and with saliva incorporation. G' and G″ either increased or were similar for xanthan and blends and decreased for starch-thickened samples. Hydrocolloid addition increased friction for all samples and was higher with saliva addition. Sensory results showed that samples with starch were perceived as thick and grainy while xanthan was perceived as smooth and slippery. A greater number of sensory attributes correlated with viscoelastic parameters compared to friction coefficients. Correlations were highest with the saliva added samples, further highlighting the importance of including saliva during instrumental testing.

Effect of inulin on pasting, thermal, rheological properties and in vitro digestibility of pea starch gel

The influence of inulin (IN) on pasting, thermal, rheological properties, and in vitro digestibility of pea starch gel was investigated. Results showed that as the concentration of IN in PS increased, the pasting temperature of PS gradually increased, while the value of peak viscosity, breakdown, and setback decreased. Rheological test suggested that all PS-IN gels were typical non-Newtonian fluids and exhibited a solid-like behavior. With the increased concentration of IN, hardness, chewiness, and gumminess of PS-IN gels significantly declined, in which the minimum value was at addition level of 20%. The presence of IN increased the gelatinization temperatures of PS-IN gels, while decreased the gelatinization enthalpy. Fourier-transform infrared spectroscopy (FT-IR) results indicated that no covalent bonding but intermolecular hydrogen bonding occurred between PS and IN. No influence of IN on the diffraction peak of PS after pasting was confirmed by X-ray diffraction analysis. In addition, IN decreased the content of rapidly and slowly digestible starch of PS, while increasing the content of resistant starch. These results will expand the application range of PS, and also provide a theoretical basis for the development of inulin-starch based products.

Estimation of viscosity and hydrolysis kinetics of corn starch gels based on microstructural features using a simplified model

Viscosity is an important rheological property, which may have impact on the glycemic response of starchy foods. However, the relationship between starch gels viscosity on its hydrolysis has not been elucidated. The aim of this work was to assess the effect of gels viscosity on the microstructure, and the kinetics of enzymatic hydrolysis of starch. Corn starch gels were prepared from starch:water ratios varying from 1:4 to 1:16. A structural model was proposed that correlated (R-square = 0.98) the porous structure (cavity sizes, thickness walls) of gels and its viscosity. Kinetics constants of hydrolysis decreased with increasing starch content and consequently with gel viscosity. Relationships of viscosity with the microstructural features of gels suggested that enzyme diffusion into the gel was hindered, with the subsequent impact on the hydrolysis kinetics. Therefore, starch digestibility could be governed by starch gels viscosity, which also affected their microstructure.

Effects of carboxymethyl chitosan on physicochemical, rheological properties and in vitro digestibility of yam starch

The effects of carboxymethyl chitosan (CMCS) on the pasting, rheological, and physical properties of yam starch (YS) were investigated. Different concentrations of CMCS were added to the YS, followed by heating paste treatment at 95 °C. Then the blends were subjected to the determination of physicochemical, rheological properties and in vitro digestibility. Our results showed that CMCS reduced the paste viscosity of YS and the addition of CMCS did not effectively inhibit the movement of water molecules. Rheological measurements results showed that YS-CMCS blends exhibited shear thinning behavior. Furthermore, because of the presence of amylose inhibited the swelling of the starch and leaching of amylose, the addition of CMCS had no significant difference between solubility and swelling power of YS.

Effects of Auricularia auricula-judae polysaccharide on pasting, gelatinization, rheology, structural properties and in vitro digestibility of kidney bean starch

Auricularia auricula-judae polysaccharide (AP) has unique molecular structures and multiple bioactivities with excellent gel-forming property and thermal tolerance. However, few researches focus on the interactions between AP and legume starches. In this study, the effects of AP on the pasting, gelatinization, rheology, microstructure, and in vitro digestibility of kidney bean starch (KBST) were evaluated. The pasting, gelling and structural properties of AP-KBST mixtures were characterized by rapid visco analyzer, rheometry, texture analyzer, laser particle analyzer, low-field nuclear magnetic resonance, Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. And an in vitro method was employed to measure the digestibility of AP-KBST composites. The pasting viscosity, swelling degree of starch granules, viscoelasticity, gel strength, cold storage stability and water-retention capacity of KBST were enhanced with increasing AP concentration. The combination of AP and KBST exhibited a higher short-range ordered and a firmer and denser structure than that of KBST alone. Moreover, AP increased the contents of resistant starch and slowly digestible starch, which were positively correlated with the storage modulus and the degree of order, thereby suggesting that the formation of strong and ordered gel network structure by synergistic interactions between AP and KBST was responsible for the reduced starch digestibility.

Effect of Moisture Distribution Changes Induced by Different Cooking Temperature on Cooking Quality and Texture Properties of Noodles Made from Whole Tartary Buckwheat

While precooking and processing have improved the quality of gluten-free noodles, the effects of different cooking temperatures on their quality—neither gluten-free noodles nor whole Tartary buckwheat noodles—have rarely been clarified. This study investigated the key role of moisture distribution induced by different cooking temperatures in improving the noodle quality of whole Tartary buckwheat. The results showed that cooking temperatures higher than 70 °C led to a sharp increase in cooking loss, flavonoid loss and the rate of broken noodles, as well as a sharp decrease in water absorption. Moreover, the noodles cooked at 70 °C showed the lowest rate of hardness and chewiness and the highest tensile strength of all cooking temperatures from 20 °C to 110 °C. The main positive attribute of noodles cooked at 70 °C might be their high uniform moisture distribution during cooking. Cooking at 70 °C for 12 min was determined as the best condition for the quality improvement of whole Tartary buckwheat noodles. This is the first study to illustrate the importance of cooking temperatures on the quality of Tartary buckwheat noodles. More consideration must also be given to the optimal cooking conditions for different gluten-free noodles made from minor coarse cereals.

Effects of Pectin on the Physicochemical Properties and Freeze-Thaw Stability of Waxy Rice Starch

In this study, the effects of the addition of pectin (PEC) on the physicochemical properties and freeze-thaw stability of waxy rice starch (WRS) were investigated. As PEC content increased, the pasting viscosity and pasting temperature of WRS significantly increased (p < 0.05), whereas its breakdown value and setback value decreased. Differential scanning calorimetry showed that the addition of PEC increased the gelatinization temperature of WRS, but decreased its gelatinization enthalpy. Rheological measurements indicated that the addition of PEC did not change the shear-thinning behavior of WRS-PEC blends, and the storage modulus and loss modulus were positively correlated with PEC content. Moreover, the textural parameter of WRS decreased with the increase in PEC content. Furthermore, the addition of PEC decreased the transmittance of starch paste, but enhanced the freeze-thaw stability of WRS to some extent. These results may contribute to the development of WRS-based food products.

The protective mechanism of a debranched corn starch/konjac glucomannan composite against dyslipidemia and gut microbiota in high-fat-diet induced type 2 diabetes

This study aimed to explore the protection mechanism of a debranched corn starch/konjac glucomannan (DCSK) composite against type 2 diabetes (T2D) related to dyslipidemia and gut microbiota in mice fed on a high-fat diet (HFD). The results showed that the consumption of DCSK led to a significant improvement in the biochemical parameters and physiological indices associated with T2D in the HFD group, including the decrease in blood glucose, triglyceride, total cholesterol, and high-density lipoprotein cholesterol levels, as well as the suppression of the oxidative stress of the liver and kidneys. Furthermore, the health of the intestinal microbiota in the HFD-fed mice was altered dramatically after DCSK consumption. Metabolomics revealed 13 differential metabolites strongly linked to DCSK intervention, and DCSK supplementation regulated amino acid metabolism, nucleotide metabolism, and lipid metabolism. These findings demonstrated that DCSK has an outstanding ability to improve hyperglycemia, hyperlipidemia, and gut microbiota associated with T2D.

Comparison of quercetin and rutin inhibitory influence on Tartary buckwheat starch digestion in vitro and their differences in binding sites with the digestive enzyme

Inhibitory effects of flavonoids on starch digestibility were well known, but the structural mechanism was not clear. This study was focused on the diverse effect of quercetin and rutin on digestibility of Tartary buckwheat starch. Results showed that quercetin and rutin reduced the starch digestion by altering starch structure in bound forms and inhibiting digestive enzyme activity in free forms simultaneously, and quercetin showed a stronger effect than rutin. Molecular docking and saturation transfer difference-nuclear magnetic resonance (STD-NMR) revealed different binding site of rutin from quercetin was due to its hydroxyl and hydrogen on the glycoside structure. Rutin interacted with enzymes mainly by CH and OH on the glycoside structure which induced steric hindrance and restricted the inhibitory effect of quercetin fraction. The glycoside structure weakened inhibition of rutin on digestive enzymes in free forms rather than influence its anti-digestive effects in bound forms with starch.

Pectin as Rheology Modifier of a Gelatin-Based Biomaterial Ink

Gelatin is a natural biopolymer extensively used for tissue engineering applications due to its similarities to the native extracellular matrix. However, the rheological properties of gelatin formulations are not ideal for extrusion-based bioprinting. In this work, we present an approach to improve gelatin bioprinting performances by using pectin as a rheology modifier of gelatin and (3-glycidyloxypropyl)trimethoxysilane (GPTMS) as a gelatin-pectin crosslinking agent. The preparation of gelatin-pectin formulations is initially optimized to obtain homogenous gelatin-pectin gels. Since the use of GPTMS requires a drying step to induce the completion of the crosslinking reaction, microporous gelatin-pectin-GPTMS sponges are produced through freeze-drying, and the intrinsic properties of gelatin-pectin-GPTMS networks (e.g., porosity, pore size, degree of swelling, compressive modulus, and cell adhesion) are investigated. Subsequently, rheological investigations together with bioprinting assessments demonstrate the key role of pectin in increasing the viscosity and the yield stress of low viscous gelatin solutions. Water stable, three-dimensional, and self-supporting gelatin-pectin-GPTMS scaffolds with interconnected micro- and macroporosity are successfully obtained by combining extrusion-based bioprinting and freeze-drying. The proposed biofabrication approach does not require any additional temperature controller to further modulate the rheological properties of gelatin solutions and it could furthermore be extended to improve the bioprintability of other biopolymers.

Effect of four viscous soluble dietary fibers on the physicochemical, structural properties, and in vitro digestibility of rice starch: A comparison study

The effect of carboxymethyl cellulose (CMC), high-methoxyl pectin (HMP), konjac glucomannan (KGM), and xanthan gum (XG) on the physicochemical, structural properties, and digestibility of rice starch were investigated and compared. The four viscous soluble dietary fibers (VSDFs) increased the viscosity, storage modulus and loss modulus while decreased the pasting temperature and gelatinization enthalpy. Moreover, XG produced the lowest peak viscosity and dynamic modulus compared with the other VSDFs. Furthermore, the degree of short-range ordered structure of starch with KGM increased from 0.8448 to 0.8716; and the relative crystallinity of starch with XG increased by 12%. An ordered and reunited network structure was observed in SEM. In addition, VSDF inhibited the digestibility of rice starch and significantly increased the resistant starch content. This study compared the effect of four VSDFs on the physicochemical, structural and digestion properties of rice starch to fully understand and develop their application to starchy foods.

Rheological and technological characterization of red rice modified starch and jaboticaba peel powder mixtures

Properties of modified starch and its interaction with functional raw materials are of great interest to the food industry. Thus, this study aimed to evaluate the rheological and technological characterization of starches modified by the action of the enzymes α-amylase and amyloglucosidase and their mixtures with jaboticaba peel powder. The parameters of firmness, gumminess, and final viscosity of starches paste increased, and the tendency to setback was reduced with the addition of jaboticaba peel powder. Starches and mixtures presented shear-thinning behavior. The addition of jaboticaba peel powder to starches increased water, oil, and milk absorption capacity, while syneresis remained stable over the storage period. The addition of jaboticaba peel powder had a positive effect on native and modified starches' rheological and technological properties, qualifying it as an alternative for developing new functional food products.

The role of alkali in sweet potato starch-Mesona chinensis Benth polysaccharide gels: Gelation, rheological and structural properties

According to the Chinese traditional black jelly production process, a critical step to ensure the quality of jelly is to add alkali to it. In this study, the effects of sodium carbonate (Na₂CO₃) and sodium bicarbonate (NaHCO₃) on the pasting, rheological, textural, and structural properties of sweet potato starch (SPS)-Mesona chinensis Benth polysaccharide (MCP) gels were evaluated. Adding Na₂CO₃ at low concentration reduced the final viscosity (FV) of SPS-MCP gels, whereas adding it at a high concentration increased the FV. Adding NaHCO₃ can increase the FV of SPS-MCP gels in a concentration-dependent manner. Rheological results indicated that adding NaHCO₃ at a low concentration decreased the storage modulus of SPS-MCP gels, whereas adding it at a high concentration increased the storage modulus. The storage modulus of SPS-MCP gels increased with increasing concentration of NaHCO₃. The addition of Na₂CO₃ and NaHCO₃ improved the textural properties of SPS-MCP gels and decreased the water mobility. Infrared results indicated that adding alkali can enhance the hydrogen bonding between SPS and MCP. Scanning electron microscopy results suggested that alkali can reduce the size of gels, and make the structure more compact.

The preparation of modified nano-starch and its application in food industry

Starch, which is a carbohydrate polymer with a semicrystalline granular structure, has been the subject of academic research for decades due to its renewable and biodegradable property as well as various applications in food, pharmaceutical and other industries. Nano-starch (NS) is a novel type of starch material with unique physiochemical properties due to its small size. However, the nano-size nature of NS determines its tendency to agglomeration as a natural process to approach a thermodynamically steady state, and the single hydroxyl functional group is also not favorable to its applications in hydrophobic environments. Thus, modified-NS with improved dispersion property, hydrophobicity, and stability is emerging as a new research direction. However, information about modified-NS is sporadic in literature, and a systematic review from its preparation, application, the problem and challenge as well as related health concerns is carried out to further the understanding of modified-NS. It is expected that the theoretical basis and new insight into the development of modified-NS will be improved.

Structural, functional and digestibility characteristics of sorghum and corn starch extrudates (RS3) as affected by cold storage time

The aim of the study was to compare the properties of resistant starch (RS₃) formed during extrusion of corn and sorghum starches. The extrudates were stored for 7 and 14 days at 4 °C to allow for molecular rearrangement i.e. retrogradation. The extruded starches were analyzed for enzymatic digestibility, long range (X-ray diffraction, XRD) and short range (FTIR) molecular order, thermal characteristics (DSC) and rheological properties as affected by temperature. The highest RS (70.64%) was obtained for sorghum extrudate (ES₁₄) as compared to corn extrudate (EC₁₄) (64.90%), on 14th day of storage. The increase in RS correlates with the increase in percent crystallinity (%Xc), too. The (ES₁₄) reported the highest %Xc among all extrudates i.e.37.83. The XRD results showed an additional peak at 13° and 20°, reflecting the formation of V-type pattern in all samples. The FTIR spectroscopy also exhibited increase in the ratio of 1047 cm^-1/1151 cm^-1 and 1047 cm^-1/1022 cm^-1. The extruded starch showed significantly higher thermal stability and lower cold paste viscosity. The significant (p ≤ 0.05) decrease in the glycemic index was obtained as the storage time increased. The (ES₁₄) exhibited glycemic index equal to (EC₁₄) i.e.55.53 and 52.53, respectively; thereby making it a suitable substitute of corn starch.