Native Corn Starch Research Articles

Synthesis and characterization of glyceryl starch and determination of molar substitution

In this work, glyceryl starch was prepared by changing the reactant ratio (v/w) of etherifying agent/starch using chlorinated glycerol as etherifying agent. The molar substitution of glyceryl starch was determined. The modified colorimetric method for the determination of molar substitution was described. The glyceryl starch was characterized by using FT-IR and 1H NMR spectroscopy. Experimental analyses were performed to investigate the effect of dihydroxypropylation on a range of starch properties, including degree of crystallinity, granule morphology, paste clarity, and retrogradation stability and compare them with those of the native corn starch.

High-performance thermoplastic starch/poly(butylene adipate-co-terephthalate) blends through synergistic plasticization of epoxidized soybean oil and glycerol

Utilizing starch, an abundant polysaccharide, as the renewable filler to blend with poly(butylene adipate-co-terephthalate) (PBAT) is a feasible tactic to construct cost-effective and high-performance biodegradable materials. It's worth noting that the thermal processing properties of starch can be manipulated by its plasticized behavior. Herein, epoxidized soybean oil (ESO) and glycerol were used as the plasticizer for native corn starch and the plasticized starch was integrated with PBAT to manufacture starch-based biodegradable blend films. ESO breaks the hydrogen bonds between starch chains through the fatty chains grafting reaction and increases the distance between starch molecular chains due to the large molecular weight of ESO. Meanwhile, glycerol molecules are incorporated into the starch molecular chains, and fatty chains grafted starch chains, effectively reducing the intermolecular forces of molecular chains. On account of the synergistic plasticization of ESO and glycerol which possess good compatibility with PBAT, the PSG20E10 blend film achieved a tensile strength, an elongation at break of 16.11 MPa and 612.09 %, and the balanced water and oxygen permeability properties.

Enhancing the Mechanical Properties of Corn Starch Films for Sustainable Food Packaging by Optimizing Enzymatic Hydrolysis.

The objective of this study was to investigate the effects of enzymatic hydrolysis using α-amylase from Bacillus amyloliquefaciens on the mechanical properties of starch-based films. The process parameters of enzymatic hydrolysis and the degree of hydrolysis (DH) were optimized using a Box-Behnken design (BBD) and response surface methodology (RSM). The mechanical properties of the resulting hydrolyzed corn starch films (tensile strain at break, tensile stress at break, and Young's modulus) were evaluated. The results showed that the optimum DH for hydrolyzed corn starch films to achieve improved mechanical properties of the film-forming solutions was achieved at a corn starch to water ratio of 1:2.8, an enzyme to substrate ratio of 357 U/g, and an incubation temperature of 48 °C. Under the optimized conditions, the hydrolyzed corn starch film had a higher water absorption index of 2.32 ± 0.112% compared to the native corn starch film (control) of 0.81 ± 0.352%. The hydrolyzed corn starch films were more transparent than the control sample, with a light transmission of 78.5 ± 0.121% per mm. Fourier-transformed infrared spectroscopy (FTIR) analysis showed that the enzymatically hydrolyzed corn starch films had a more compact and solid structure in terms of molecular bonds, and the contact angle was also higher, at 79.21 ± 0.171° for this sample. The control sample had a higher melting point than the hydrolyzed corn starch film, as indicated by the significant difference in the temperature of the first endothermic event between the two films. The atomic force microscopy (AFM) characterization of the hydrolyzed corn starch film showed intermediate surface roughness. A comparison of the data from the two samples showed that the hydrolyzed corn starch film had better mechanical properties than the control sample, with a greater change in the storage modulus over a wider temperature range and higher values for the loss modulus and tan delta, indicating that the hydrolyzed corn starch film had better energy dissipation properties, as shown by thermal analysis. The improved mechanical properties of the resulting film of hydrolyzed corn starch were attributed to the enzymatic hydrolysis process, which breaks the starch molecules into smaller units, resulting in increased chain flexibility, improved film-forming ability, and stronger intermolecular bonds.

Effects of Sodium Alginate and Guar Gum Matrices on the Structure and In Vitro Digestion of Native Corn Starch after Encapsulation Using Spray Drying

AbstractThe study aims to investigate the influence of hydrocolloid matrices, including sodium alginate (SA) and guar gum (GG), on the digestive properties of native corn starch (NCS). The native starch is encapsulated with SA (1% w/v), SA (0.75% w/v) + GG (0.25% w/v), SA (0.50% w/v) + GG (0.50% w/v), SA (0.25% w/v) + GG (0.75% w/v), and GG (1% w/v) through a laboratory‐scale spray drying process. The results reveal novel comparative and cooperative effects of encapsulant materials on starch hydrolysis. SA is found to be a superior encapsulant in terms of enhancing the slowly digestible starch (SDS) and resistant starch (RS) contents and improving the thermal stability of NCS, which is attributed to its rough matrix structure. This effect is attributed to the rough matrix structure of SA, which may offer greater resistance to water and enzyme penetration. The combination of 0.75% w/v SA + 0.25% w/v GG is found to be the most effective in reducing digestibility and enhancing thermal stability (p < 0.05), likely due to synergistic interactions between the two hydrocolloids. These findings provide valuable information on the effects of hydrocolloid matrices on the digestive properties of NCS and lay the foundation for future research.

Exploring the mechanism of high hydrostatic pressure on the chemical activity of starch based on its structure and properties changes

High hydrostatic pressure (HHP) could induce changes in the structure and properties of starch. Native corn starch was treated and octenyl succinic anhydride (OSA)-modified corn starch was prepared under different pressures (200, 350, 500 and 600 MPa) at 40℃ for 20 min. The mechanism of HHP on the chemical activity of starch was elucidated by analyzing the relationship between the changes of native starch structure and properties and the quality of OSA-modified starch. Results showed that HHP not only helped water and OSA to penetrate the starch granules but also made the structure of starch granules undergone three changes similar to mechanochemical effects. The starch granules treated by 200 MPa were in the stress stage, and the starch granules treated by 500 MPa were in the transition stage from aggregation to agglomeration. Proper pressure treatment could significantly improve chemical activity of starch and quality of OSA-modified starch.

Impact of tamarind seed gum on the viscosity behavior, thermal properties, and extrusion characteristics of native corn starch

Tamarind seed gum (TSG) is a cold-swelling hydrocolloid with remarkable processing stability and starch synergy. Its use in direct expanded extruded foods has not been documented. The thermal and pasting viscosity properties of six TSG (0%, 0.5%, 1.0%, 2.5%, 5.0%, and 7.5% TSG) and native corn starch blends were characterized by differential scanning calorimetry and ViscoQuick, respectively. These same blends were extruded using a corotating twin-screw extruder at four screw speeds (SSs) (150, 300, 450, and 600rpm). System back pressure, motor torque, and specific mechanical energy (SME) were measured. Extrudate quality metrics, such as expansion ratio (ER), water absorption index (WAI), and water solubility index (WSI), were also measured. The pasting viscosities indicated that TSG inclusion increases viscosity but also makes the starch-gum paste more susceptible to permanent shear degradation. The thermal analysis indicated that TSG inclusion narrowed the melting endotherms and lowered the energy required for melting (p<0.05) at higher inclusion levels. Extruder back pressure, motor torque, and SME decreased with increasing TSG levels (p<0.05) as the TSG effectively lowered the melt viscosity at high usage rates. The ER reached a maximum of 3.73 with a 2.5% TSG level extruded at 150rpm (p<0.05). The WAI of extrudates increased with TSG inclusion rate at equivalent SSs, whereas WSI behaved oppositely (p<0.05). Small inclusions of TSG can improve the expansion properties of starch, whereas larger inclusions result in a lubrication effect that mitigates the shear-induced depolymerization of starch. PRACTICAL APPLICATION: The impact of cold-water soluble hydrocolloids, including tamarind seed gum, on the extrusion process, is poorly understood. From this work, tamarind seed gum effectively modifies the viscoelastic and thermal characteristics of corn starch in a way that enhances the direct expansion characteristics of the starch during extrusion processing. The effect is more beneficial at lower gum inclusion levels as higher levels result in reduced capabilities to translate shear from the extruder into useful transformations of the starch polymers during processing. Small amounts of tamarind seed gum could be used to improve the quality of extruded starch puff snacks.

Highly selective adsorption of Hg (II) from aqueous solution by three-dimensional porous N-doped starch-based carbon.

For the first time, N-doped carbon materials with 3D porous-layered skeleton structure was synthesized through a one-step co-pyrolysis method, which was fabricated by co-pyrolysis of natural corn starch and melamine using metal catalysts (Ni (II) and Mn (II)). The 3D-NC possessed a heterogeneously meso-macroporous surface with a hierarchically connected sheet structure inside. Batch adsorption experiments suggested that highly selective adsorption of Hg (II) by the 3D-NC could be completed within 90min and had maximum adsorption capacities as high as 403.24mg/g at 293K, pH = 5. The adsorption mechanism for Hg (II) was carefully evaluated and followed the physical adsorption, electrostatic attraction, chelation, and ion exchange. Besides, thermodynamic study demonstrated that the Hg (II) adsorption procedure was spontaneous, endothermic, and randomness. More importantly, the 3D-NC could be regenerated and recovered well after adsorption-desorption cycles, showing a promising prospect in the remediation of Hg (II)-contaminated wastewater.

Structural and physicochemical properties of resistant starch under combined treatments of ultrasound, microwave, and enzyme

The structural characteristics and physicochemical properties of native corn starch (NCS) and resistant starch (RS) prepared by enzymatic hydrolysis (RS-E), microwave-enzymatic hydrolysis (RS-ME), ultrasound assisted enzymatic hydrolysis (RS-UE), and microwave-ultrasound assisted enzymatic hydrolysis (RS-MUE) were investigated. The results showed that the combined treatments of ultrasound, microwave, and enzyme resulted in increases in RS content, amylose content, and solubility with a decrease in swelling power. RS-MUE exhibited the lowest digestibility, with a 41.71 % RS content. Particle-size distribution and scanning electron microscopy analyses demonstrated that RS samples exhibited larger granule sizes and rougher surfaces with irregular shapes. The Fourier transform infrared spectroscopy and X-ray diffraction pattern analysis demonstrated that no new groups were created during the modification processes, the crystal structure of all RS samples changed from A to B + V, and the short-range order and relative crystallinity of RS-E, RS-ME, RS-UE, and RS-MUE increased. RS-MUE exhibited the highest molecular order R1047/1022 value (0.8769) and relative crystallinity (45.54 %). These results suggested that the new technology combining microwave, ultrasound, and enzyme for improving RS content is effective and has potential for application in the production of RS and low glycemic index foods.

Porous Microparticles of Corn Starch as Bio-Carriers for Chia Oil.

Native corn starch and pretreated corn starch were treated with α-amylase, glucoamylase and mixtures of both to generate starches with high porosity with conserved granular structure. Porous starches were characterized; particle size distribution analysis, nitrogen adsorption-desorption analysis, scanning electron microscopy, water and oil adsorption capacity, differential scanning calorimeter, X-ray diffraction and damaged starch techniques were used. The α-amylase/glucoamylase mixture at the highest dose was the best treatment to generate porous starches with interesting adsorption capacity and granular structure conservation. Selected starches were impregnated with chia oil using a vacuum. Pretreated corn starch modified with the α-amylase/glucoamylase mixture showed no significant differences on impregnation capacity compared with native starch with a similar enzyme treatment. The highest oxidative stability was achieved with pretreated porous starch impregnated with 10 to 25% chia oil, compared with the bulk oil (5.37 to 4.72 and 2.58 h, respectively). Results have demonstrated that vacuum impregnation could be a potential technique for the incorporation of oil in porous structures based on starch and porous starches obtained by enzymatic hydrolysis are a promising material for the incorporation and protection of oils susceptible to oxidation.

Inca Peanut Seed Albumin Promotes the Retrogradation of Corn Starch

While starch and protein are two major biopolymer components that usually coexist in foods, how protein influences starch retrogradation, and subsequently the food matrix structure and properties, is complex and dependent on factors such as protein and starch types. Herein, the effect of the addition of Inca peanut seed albumin (IPA, ≤10%) on the retrogradation of native corn starch (NCS) upon aging for ≤7 days was investigated. Dynamic rheological results show that the addition of IPA significantly promoted the short-term (1 day) retrogradation of NCS as reflected by the increased storage modulus and smaller loss tangent. Differential scanning calorimetry results indicate that IPA increased the retrogradation enthalpy, especially with a high content (≥5%) of IPA (P < 0.05). In addition, with a higher level of IPA, the hardness increased after storage for 1 or 7 days. The ratio of the band intensities at 1047 and 1022 cm–1 and the relative crystallinity of the NCS/IPA mixture also increased after storage, especially with a high content (≥5%) of IPA. Scanning electron microscopy results show that the addition of IPA increased the surface roughness and porosity of the starch gel after storage. This work shows that the addition of IPA as a plant protein could be a promising way to modify the properties of starch-based foods by inducing retrogradation while enhancing the nutritional and functional properties of foods.

STUDY OF THE PROCESSES OF WASTEWATER TREATMENT FOR REUSE IN THE PULP AND PAPER INDUSTRY

Nowadays, more than 80% of cardboard and paper products of Ukrainian mills are made from waste paper – secondary fibers that differ in their chemical and physical properties from primary cellulosic fibers. Characteristic feature of secondary fibers is the presence of a large number of small fibers, which negatively affects the quality of finished products, mass retention on the grid during the formation of paper or cardboard, which leads to pollution of wastewaters. Despite its environmental friendliness and economy, waste paper is also characterized by the presence of various pollutants, the formation of which is associated with the process of paper formation, storage of finished products, and their use. As a result of the preparation of the mass from secondary fibers, there is a transition of pollutants from the waste paper to the wastewater in the form of colloidally dispersed and soluble substances, which lead to the pollution of circulating water. Purification of water and its reuse in technological processes is an important task of paper industry mills. The results show that more than 90% of the secondary fibers have a length that does not exceed 1 mm, while in the primary cellulose fiber from coniferous wood about 53% of the fibers have a length of more than 1 mm. The high content of short fibers in the paper mass affects the processes of paper formation, worsening them, and a decrease in the retention of the fiber on the grid of the paper or cardboard machine is observed, causing the pollution of wastewater. The results of the study of coagulation of industrial wastewater with the content of suspended solids 1520 and 3200 mg/dm3 from the production of cardboard from recycling paper show that the best coagulants are A1(OH)C12 and A12(OH)5C1. The maximum efficiency of water purification of only 92.5% was achieved at the suspended solids content of 1520 mg/dm3, while for wastewater with a suspended solids concentration of 3200 mg/dm3 98.0% was obtained. To develop a scheme for deep purification of wastewaters, it is important to understand which components are removed from water more easily and which are more difficult during coagulation. For this purpose, studies on coagulation of model suspensions of starches, bentonite and kaolin using inorganic coagulants were conducted. It was established that coagulation of native corn starch suspension with inorganic coagulants is effective. However, in the case of using modified starches, the removal of cationic starches is reduced. The efficiency of water purification in the removal of bentonite by sedimentation-filtration with the use of coagulants is quite high. The degree of purification reaches 80.8-98.1%. The filtering stage allows the degree of purification to be further increased. Research on the processes of purification of model kaolin suspensions shows that mechanical and physico-chemical methods are ineffective in removing this mineral filler.

Physicochemical, Pasting, and Thermal Properties of Native Corn Starch-Mung Bean Protein Isolate Composites.

Starch is widely used in food and non-food industries because of its unique characteristics. However, native starch shows some weaknesses that restrict its applications. Recently, some studies have demonstrated the benefits of using protein to overcome these limitations. Therefore, the aim of the present study was to investigate the effect of mung bean protein isolate (MBPI) (2%, 4%, 6%, and 8%) on the physicochemical, pasting, and thermal properties of native corn starch (NCS), as a novel starch-protein composite. Higher swelling power (SP), water absorbance capacity (WAC), and solubility values of NCS were observed with increasing MBPI concentration. Additionally, by the addition of MBPI, the rapid visco analyzer (RVA) showed a reduction in pasting temperature (77.98 to 76.53 °C), final viscosity (5762 to 4875 cP), and setback (3063 to 2400 cP), while the peak viscosity (4691 to 5648 cP) and breakdown (1992 to 3173 cP) increased. The thermal properties of NCS/MBPI gels investigated by differential scanning calorimetry (DSC) showed higher onset, peak, and conclusion temperatures (69.69 to 72.21 °C, 73.45 to 76.72 °C, and 77.75 to 82.26 °C, respectively), but lower gelatinization enthalpy (10.85 to 8.79 J/g) by increasing MBPI concentration. Fourier transform infrared spectroscopy (FT-IR) indicated that the addition of MBPI decreased the amount of hydrogen bonds within starch. Furthermore, after three cycles of freeze-thaw shocks, the syneresis of NCS-MBPI composites decreased from 38.18 to 22.01%. These results indicated that the MBPI could improve the physicochemical properties of NCS, especially its syneresis and retrogradation characteristics.

Influence of thickeners (microfibrillated cellulose, starch, xanthan gum) on rheological, tribological and sensory properties of low-fat mayonnaises

Microfibrillated cellulose (MFC) is obtained by high-shear treatment of cellulose. MFC is suitable for use as clean-label, low-calorie thickener in semi-solid foods such as mayonnaises due to its high water holding capacity. The aim of this study was to determine the effect of type and concentration of thickener on rheological, tribological and sensory properties of low-fat mayonnaises. Low-fat mayonnaises were prepared with four types of thickeners (MFC, chemically modified starch, native waxy corn starch, xanthan gum) at three concentrations. Higher biopolymer concentrations resulted in increased shear viscosities, G′ and G″, yield stress and enhanced lubrication (i.e. lower friction coefficients). Mayonnaises with modified starch and xanthan gum generally had higher shear viscosity and yield stress compared to mayonnaises with comparable concentrations of MFC and waxy corn starch. MFC-thickened mayonnaises had highest G’, G” and boundary friction coefficients. Sensory properties of mayonnaises were determined using the Rate-All-That-Apply (RATA) method (n = 80). Addition of xanthan gum induced high sliminess and pulpiness, and low melting, creaminess and smoothness. Sensory properties of mayonnaises with MFC were generally similar to those with modified and waxy corn starch, despite differences in appearance (increased yellowness and slightly lower glossiness). Multiple Factor Analysis revealed that more shear-thinning mayonnaises were perceived as slimy. Boundary friction was negatively correlated with stickiness, while friction at the start of the hydrodynamic regime was positively correlated with melting sensations. We conclude that microfibrillated cellulose can be used as a thickener in low-fat mayonnaise as an alternative to commercially used chemically modified starch without considerably affecting its sensory texture properties.

Physical, barrier, and thermal properties characterization of edible films from composite mixtures of starch and starch derivatives

In the search for sustainable and ecological alternatives in food packaging, the use of starch as one of the most abundant biopolymer resources to formulate edible films has been studied. Nonetheless, compatibility with other starch derivatives, such as dextrin and/or chemically modified starch, has not been explored yet. The objective of this research was to characterize opacity, water vapor barrier capability, and thermal properties of composite edible films, by a mixture design approach, formulated with three types of commercial chemical modified starch mixed with native corn starch and dextrin. Lower opacity in edible films was related to more soluble material, where the main effect of dextrin was the rise of soluble material and lower water vapor permeability. A more permeable film can be obtained with Nifrastarch and lower permeability with Gelamil. The type of chemically modified starch used in edible films for edible packaging can be decided according to the characteristics of the food in question, i.e., moisture, color, permeability, or edible film solubility for active packaging.

Effect of dandelion root polysaccharide on structure, rheology and retrogradation properties of corn starch during storage

SummaryThe influence of dandelion root polysaccharide (DRP) on the retrogradation characteristics of corn starch (CS) in the process of storage was studied. Compared with native corn starch gel, the blue value (BV), hardness and syneresis were significantly decreased with the increasing of DRP concentration. Fourier transform infrared (FT‐IR) and X‐ray diffraction (XRD) showed that DRP addition inhibited the recrystallisation of CS during retrogradation. In addition, the dynamic rheological behaviours confirmed that DRP could enhance the shear stability and reduce the elastic properties of corn starch gel. These data showed DRP had potential application value in delaying starch retrogradation and improving food texture.

Characterization of microbial intolerances and ruminal dysbiosis towards different dietary carbohydrate sources using an in vitro model.

AimThis study aimed to characterize the critical points for determining the development of dysbiosis associated with feed intolerances and ruminal acidosis.Methods and ResultsA metabologenomics approach was used to characterize dynamic microbial and metabolomics shifts using the rumen simulation technique (RUSITEC) by feeding native cornstarch (ST), chemically modified cornstarch (CMS), or sucrose (SU). SU and CMS elicited the most drastic changes as rapidly as 4 h after feeding. This was accompanied by a swift accumulation of d‐lactate, and the decline of benzoic and malonic acid. A consistent increase in Bifidobacterium and Lactobacillus as well as a decrease in fibrolytic bacteria was observed for both CMS and ST after 24 h, indicating intolerances within the fibre degrading populations. However, an increase in Lactobacillus was already evident in SU after 8 h. An inverse relationship between Fibrobacter and Bifidobacterium was observed in ST. In fact, Fibrobacter was positively correlated with several short‐chain fatty acids, while Lactobacillus was positively correlated with lactic acid, hexoses, hexose‐phosphates, pentose phosphate pathway (PENTOSE‐P‐PWY), and heterolactic fermentation (P122‐PWY).ConclusionsThe feeding of sucrose and modified starches, followed by native cornstarch, had a strong disruptive effect in the ruminal microbial community. Feed intolerances were shown to develop at different rates based on the availability of glucose for ruminal microorganisms.Significance and Impact of the studyThese results can be used to establish patterns of early dysbiosis (biomarkers) and develop strategies for preventing undesirable shifts in the ruminal microbial ecosystem.

Optimization of Corn Resistant Starch Preparation by Dual Enzymatic Modification Using Response Surface Methodology and Its Physicochemical Characterization.

Corn starch was dually modified using thermostable α-amylase and pullulanase to prepare resistant starch (RS). The concentration of starch liquid, the amount of added thermostable α-amylase, the duration of enzymatic hydrolysis and the amount of added pullulanase were optimized using RSM to increase RS content of the treated sample. The optimum pretreatment conditions were 15% starch liquid, 3 U/g thermostable α-amylase, 35 min of enzymatic hydrolysis and 8 U/g pullulanase. The maximum RS content of 10.75% was obtained, and this value was significantly higher than that of native corn starch. The degree of polymerization (DP) of the enzyme-modified starch decreased compared with that of native starch. The scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were performed to assess structural changes in native and pretreated starch. The effect of dual enzyme pretreatment on the structure and properties of corn starch was significant. Unlike the untreated one, the pretreated corn starch showed clear pores and cracks. Significant differences in RS contents and structural characterization between starch pretreated and untreated with dual enzymes demonstrated that the dual enzyme modification of corn was effective in enhancing RS contents.

Effects of Mung Bean (Vigna radiata) Protein Isolate on Rheological, Textural, and Structural Properties of Native Corn Starch.

It is critical to understand the starch–protein interactions in food systems to obtain products with desired functional properties. This study aimed to investigate the influence of mung bean protein isolate (MBPI) on the rheological, textural, and structural properties of native corn starch (NCS) and their possible interactions during gelatinization. The dynamic rheological measurements showed a decrease in the storage modulus (G’) and loss modulus (G”) and an increase in the loss factor (tan δ), by adding MBPI to NCS gels. In addition, the textural properties represented a reduction in firmness after the addition of MBPI. The Scanning electron microscope (SEM) images of the freeze-dried NCS/MBPI gels confirmed that the NCS gel became softer by incorporating the MBPI. Moreover, X-ray diffraction (XRD) patterns showed a peak at 17.4°, and the relative crystallinity decreased with increasing MBPI concentrations. The turbidity determination after 120 h refrigerated storage showed that the addition of MBPI could reduce the retrogradation of NCS gels by interacting with leached amylose. Additionally, the syneresis of NCS/MBPI gels decreased at 14 days of refrigerated storage from 60.53 to 47.87%.

Potential interactions between starch and fruit pomace may impact the expansion ratio of direct expanded extrudates.

Due to their dense characteristics, direct-expanded products fortified with insoluble fiber are generally not well accepted. Understanding the interactions between starch and fiber could help to effectively choose and modify ingredients to produce products containing high amounts of fiber. Therefore, this study aims to explain the interplay between two starches (native and waxy corn) and two pomace types (blueberry and cranberry). Blends up to 100% of pomace were extruded using a co-rotating twin-screw extruder. Raw material and milled extrudates were analyzed for their pasting and hydration properties. Fourier-transform infrared (FTIR) and solid-state nuclear magnetic resonance (NMR) spectroscopy were conducted to observe molecular changes. The expansion ratio (ER) significantly decreased as pomace was added and ranged from 3.85 for pure waxy corn starch to approximately 1 for blends that contained 80% pomace. Distinctions between the blends were observed. Particularly, at 20% of pomace inclusion, native corn starch with cranberry pomace showed a significantly higher ER. Different behaviors were also detected during the physicochemical analyses. A nonlinear trend between pomace level and water solubility as well as absorption was observed for native corn starch blends, suggesting that molecular interactions between the biopolymers occur. FTIR and NMR results give no evidence for new covalent bonds; hence, the most likely interactions occurring are hydrogen bonds. In addition to the dilution effect of pomace addition, the enhancement or weakening of such interactions between starch molecules by pomace compounds may reduce the ER.

Processing of Starch in Deep Eutectic Solvent

AbstractThe deep eutectic solvent of [choline chloride (ChCl)] [ethylene glycol (EG)] is demonstrated to be an effective non‐destructive solvent for starch processing. The pre‐gelatinized starch samples are prepared by its gelatinization, treatment, and re‐crystallization in this deep eutectic solvent and characterized by differential scanning calorimetry (DSC), gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (H‐NMR), X‐ray diffraction analyses (XRD), and scanning electron microscopy (SEM) tests. The gelatinization temperature of starch in the deep eutectic solvent of [choline chloride] [ethylene glycol] is measured using a DSC method. Compared to the native starch sample, slight increases in molecular weights and decreases in molecular weight distribution of the recovered starch samples are observed. The similar FTIR and H‐NMR spectra of the native starch and recovered starch samples suggest no reaction and variation in chemical structure during the processing. The XRD and DSC tests show that the strong micro‐granular crystalline structure of the native corn starch is destroyed during the gelatinization and treatment in the DES while new weak crystalline structure is formed during the re‐crystallization.