Modified Corn Starch Research Articles

Preparation and characterization of biodegradable polymer blends from poly(3‐hydroxybutyrate)/poly(vinyl acetate)‐modified corn starch

Biodegradable polymer blends prepared by blending poly(3‐hydroxybutyrate) (PHB) and corn starch do not form intact films due to their incompatibility and brittle behavior. For improving their compatibility and flexibility, poly(vinyl acetate) (PVAc) was grafted from the corn starch to prepare the PVAc‐modified corn starch (CSV). The resulting CSV consisted of 47.2 wt% starch‐g‐PVAc copolymer and 52.8 wt% PVAc homopolymer and its structure was verified by FT‐IR analysis. In comparison with 35°C of the neat PVAc, the glass transition temperature (Tg) of the grafted PVAc chains on starch‐g‐PVAc was higher at 44°C because of the hindered molecular mobility imposed from starch on the grafted PVAc. After blending PHB with the CSV, structure and thermal properties of the blends were investigated. Only a single Tg was found for all the PHB/CSV blends and increased with increasing the CSV content. The Tg‐composition dependence of the PHB/CSV blends was well‐fitted with the Gordon‐Taylor equation, indicating that the CSV was compatible with the PHB. In addition, the presence of the CSV could raise the thermal stability of the PHB component. It was also found that the presence of the PHB and PVAc components would not hinder the enzymatic degradation of the corn starch by α‐amylase. POLYM. ENG. SCI., 55:1321–1329, 2015. © 2015 Society of Plastics Engineers

Retrogradation kinetics of cross-linked and acetylated corn starches under high hydrostatic pressure

Retrogradation kinetics of conventionally and high hydrostatic pressure (HHP)-assisted chemically modified (cross-linked with sodium trimetaphosphate/sodium tripolyphosphate (STMP/STPP) and acetylated with acetic anhydride) corn starches were investigated. During storage at 4°C, the glass transition temperature (Tg′) and the ice melting enthalpy were measured using differential scanning calorimetry (DSC), and relative crystallinity was measured using an X-ray diffractometer (XRD). In both conventionally and HHP-assisted modified corn starches, the Tg′ value and relative crystallinity increased during first 7–10 days of storage, then stabilized, whereas the ice melting enthalpy decreased until 10 days of storage, then remained constant. HHP-assisted modified starch showed different retrogradation kinetics from conventionally modified starch. However, the retrogradation rates of both samples were lower than for native corn starch. Although the Tg′ value, the ice melting enthalpy, and relative crystallinity represent different physicochemical properties, all can be used as indicators for evaluation of starch retrogradation.

The physical and adsorption properties of different modified corn starches

In order to improve the physical and adsorption properties of native corn starch, porous starch was prepared. Furthermore, dual‐modification of starches – enzyme hydrolyzed starch followed by cross‐linking as well as enzyme hydrolysis upon cross‐linking was explored. The results suggested that enzyme hydrolyzed starch followed by cross‐linking was significantly different from enzyme hydrolysis upon cross‐linking. The granular specific surface area of the dual‐modified starches was more than thousand orders of native corn starch. Crosslinked starch phosphates and enzyme hydrolyzed starch followed by cross‐linking had higher gelatinization temperature than porous starch and cross‐linked starch followed by enzyme hydrolysis. The ΔH of crosslinked starch phosphates and dual‐modification of starches were larger than that of native corn starch and porous starch, which indicates that the cross‐linking strengthens the starch granules and hence more energy is required for disruption. The absorption capacities of enzyme hydrolyzed starch followed by cross‐linking and enzyme hydrolysis upon cross‐linking were 5 times more than that of native corn starch, crosslinked starch phosphates and porous starch. Overall, it is concluded that the combination of cross‐linking and enzyme hydrolysis is a favorable approach to increase the mechanical strength and adsorptive capacity of porous starches.

Physical and Thermal Stability of Spray-Dried Swiss Cheese Bioaroma Powder

The effect of water content on the glass transition temperature of Swiss cheese bioaroma microencapsulated with a spray dryer was determined using differential scanning calorimetry (DSC) while mass loss was determined by thermogravimetric analysis (TGA). The sorption isotherm behavior was assessed at 15–45°C. Data were fitted with different sorption models. The bioaroma microparticles were produced via spray drying in a matrix with a 1:1 ratio (w/w) of maltodextrin 20DE and modified corn starch (Capsul). The isotherms displayed Type II behavior, and the best fit was obtained by the Guggenheim–Anderson–de Boer (GAB) model (coefficient of determination R² ≥ 0.98). The DSC analysis showed that the increased equilibrium moisture content caused a significant reduction in the Tg of the microparticles. The samples stored at intermediate humidity showed thermal stability and the samples with equilibrium moisture content of 17.92% showed a lower mass loss.

Kinetics Modeling of The Column Adsorption for The Dehydration of Ethanol-Water Mixtures using Biomass Adsorbents

This study has explored the use of biomass - based adsorbents other than the conventional materials as adsorbent for the dehydration of ethanol - water mixtures. The column study was carried out using enzyme modified corn starch and un- modified corn starch for the adsorptive dehydration of ethanol - water mixtures. The effect of bed heights and flow rates on the breakthrough curves revealed that adsorption efficiency decreased with increased flow rate and increased with bed height. The throughput volume of the anhydrous ethanol - water mixtures increased with increase bed height, due to availability of more sorption sites on the adsorbents. Thomas, Yoon and Nelson, and Adams - Bohart kinetic models were used to describe the packed column study. The column kinetics was best described by Yoon and Nelson and Adams - Bohart models. The presence of the hydroxyl O - H stretch group’s spectroscopy confirmed the chemical affinity of these adsorbents for water in the ethanol - water mixture. The amorphous or crystallinity nature of the adsorbents was investigated using the X - RD analysis.

Design of Pilot Plant Packed Column for the Dehydration of Water from Ethanol-Water Mixtures

This use of biomass-based adsorbent has been explored for the column study of the adsorptive dehydration of water in ethanol-water mixtures. The column study was carried out using enzyme modified corn starch and the breakthrough curve parameters were used to design the packed bed column. The effect of flow rate on the breakthrough curves revealed that adsorption efficiency decreased with increased inflow rate. The empty bed contact time (τ) of the pilot plant packed column was 35.35 min while the breakthrough time is 40.78 min. 66.7% was the fraction of capacity left unused for the pilot plant from the design.

Thermodynamic properties, kinetics and adsorption mechanisms of Swiss cheese bioaroma powder

Water adsorption kinetics of Swiss cheese bioaroma microparticles were determined by a static method at 15°C, 25°C, 35°C and 45°C. This work used the Guggenheim–Anderson–de Boer (GAB) model to calculate thermodynamic properties of water adsorption. Additionally, this work predicted conditions for the stable storage of microparticles obtained through a spray drying encapsulation process with maltodextrin and modified corn starch (Capsul®) at a 1:1 (w/w) ratio. We evaluated the mechanisms that direct water vapor adsorption by studying enthalpy–entropy compensation. The product reached equilibrium phases after 120h of storage. The observed minimum values for the net integral entropy were indicative of maximized stability conditions of the product. At these conditions, water activity values ranged from 0.391 to 0.537, and the temperature ranged from 15°C to 35°C. An isokinetic compensation was confirmed for the adsorption phenomenon. This approach resulted in two zones, low and intermediate-high water activities. Under low moisture, the process was controlled by entropy; under intermediate-high moisture, it was driven by enthalpy.

The Effect of Varying Ingredient Composition on the Sensory and Nutritional Properties of a Pureed Meat and Vegetable

The objective of this research was to investigate the effects of ingredients and preparation methods on the sensory and nutritional properties of pureed turkey and carrots. Turkey samples varying in added liquid and muscle composition were developed. Seasoning application methods were also studied. Pureed carrots were formulated with no added thickener, added modified corn starch, rice cereal, or skim milk powder. Small changes in added liquid and seasoning application altered the perceived texture of the turkey. Pureed carrots with added modified corn starch were more slippery and firm than other samples. The addition of skim milk powder or rice cereal did not alter sensory properties but led to higher protein contents when compared to unthickened carrots. In-house formulations did not differ in sensory ratings of appearance and flavor when compared to commercial products but contained more carbohydrates. Modest changes in recipes for pureed products can improve sensory appeal and nutrient density; quality in-house products are feasible with only minor alterations.

Hydrocolloids for enhancing satiety: Relating oral digestion to rheology, structure and sensory perception

Satiety expectations can be closely related to the structural changes that take place in the mouth. An important role of hydrocolloids is to impart viscosity, which has a key effect on the feelings of richness, mouthcoating and fullness. In this study, native and modified corn starch, λ-carrageenan and guar gum were used to formulate milkshakes. Expected satiety was rated (106 consumers) and the perception of various attributes was studied. The rheological properties of the milkshakes without and with added saliva were analysed and observed with a light microscope during in vitro oral digestion.Disintegration of the swollen starch granules by saliva was observed mainly in the modified starch sample. The structure of the milkshakes prepared with λ-carrageenan and guar gum was preserved better. It could be hypothesized that the starch would provide lower expected satiety due to the extensive in-mouth disintegration. However, the sensory analysis showed that the modified starch milkshakes obtained the highest expected satiety scores, with consumers finding them homogeneous, thick in the mouth and very creamy. These results suggested that consumers related satiety more with the thick and creamy characteristics at the very start of the consumption than with the loss of structure in mouth. Sensory properties affect the assessment of the satiating capacity, especially texture, which is directly related to the orosensory exposure and, therefore, to the feeling of fullness that the milkshakes elicit. The present study casts light on the factors affecting in-mouth perception of different hydrocolloids used to design foods with enhanced satiety.

Polyphenol-rich extract from murta leaves on rheological properties of film-forming solutions based on different hydrocolloid blends

Film-forming solutions (FFS) based on sodium carboxymethylcellulose (CMC), low and high molecular weight fish-skin gelatin (LG and HG), unmodified and modified corn starch (CS and MS) and chitosan (CH) were prepared. Seven binary blends were evaluated (CH–CMC, CH–CS, CS–CMC, MS–CMC, HG–CMC and LG–CMC). The rheological properties of FFS and blends were studied as a function of the hydrocolloid blend type and as a function of polyphenol-rich extract from murta leaves (Ugni molinae Turcz) (PEML) in FFS. Steady-state flow tests and oscillatory measurements within the linear viscoelasticity region (LVR) were carried out. Flow behavior of FFS was significantly affected by the hydrocolloid blend type as well as presence or absence of PEML in the matrix. FFS behaves as non-Newtonian and pseudoplastic fluid above 0.4s−1 shear rate. The PEML formed aggregates with chitosan, leading to a gel-like structure with thirotropic behavior on CH and CH–CS solutions. PEML induced thermal stability in CH–CMC FFS. The FFS based on LG–CMC and HG–CMC were unstable with frequency when PEML was added. The FFS based on CS–CMC, MS–CMC, and CMC behaved as homogeneus solution, either without or with PEML. The viscosity, ranging between 2.75 and 8.49Pas to 2s−1 at 25°C, was suitable for the casting process and provided stable solutions in the wide frequency range and temperature studied.

Preparation of Polyacrylonitrile Initiated by Modified Corn Starch and Adsorption for Mercury after Modification

Well-defined polyacrylonitrile (PAN) was precisely synthesized via a single electron transfer-living radical polymerization (SET-LRP) initiated by corn starch modified by bromoacetyl bromide (CS-Br) with La/hexamethylenetetramine (HMTA) as a catalyst system and ascorbic acid (VC) as the reductant. Amidoxime (AO) groups as adsorption functional groups were obtained via cyano groups of PAN resins modified by hydroxylamine hydrochloride. The adsorption for mercury was discussed and the maximum uptake was 4.12 mmol/g. Film diffusion and a pseudo-second-order model were better to interpret the adsorption process. The Langmuir model was appropriate to describe the adsorption isothermal process.

Synthesis of ZnO/Zn nano photocatalyst using modified polysaccharides for photodegradation of dyes

A complete set of experiments in two aspects of studies combining the various factors affecting both the preparation and photocatalytic activity of ZnO/Zn nanocomposite obtained using corn starch and cellulose (native and modified) as chelating agents for the photodegradation of methylene blue, and congo red was carried out and discussed. The resulting ZnO/Zn nanoparticles obtained using modified polysaccharides exhibited super catalytic capability. The ZnO/Zn nanoparticles possessed favored surface area (11.8443–15.7100m2/g) and pore size (12.3473–13.7453nm). The photocatalytic degradation of nano ZnO/Zn was directly proportional to the surface area of nano ZnO/Zn. Regardless of the dye pollutants, nano ZnO/Zn obtained using modified corn starch showed enhanced catalytic activity than that of cellulose and methylene blue had comparatively faster degradation rate. Our findings shed light on the optimization of both preparation conditions of photocatalysts and their photocatalytic experimental conditions.

Thermal properties and crystallization behavior of thermoplastic starch/poly(ɛ-caprolactone) composites

TPS/PCL composites were prepared by PCL melt blending with modified corn starch. The structure, thermal properties, morphology and crystallization behavior of these composites were investigated by FTIR, TGA, SEM, XRD and DSC. FTIR confirmed the existence of the interaction between PCL and TPS, whereas TGA showed that the thermal stability was decreased by the addition of TPS. Meanwhile, SEM showed a weak interfacial adhesion with increasing TPS. According to the Avrami theory, TPS functioned as a nucleating agent to improve the crystallinity rate of PCL. However, the XRD analysis revealed that the crystallinity decreased. At the same time, the ΔEa of the composites was higher than those of neat PCL. These changes in values all indicated that mobility constraints existed in the PCL chains with the increasing of TPS, which leaded to a drop in the crystallization ability of PCL.

Effects of hydrothermal pretreatment on subsequent octenylsuccinic anhydride (OSA) modification of cornstarch

Cornstarch granules were hydrothermally pretreated and then esterified with octenylsuccinic anhydride (OSA). The physicochemical properties of cornstarch and hydrothermally pretreated OS-starch (H-OS-starch) were investigated. Results showed that hydrothermal pretreatments significantly increased the degree of substitution (DS) and reaction efficiency (RE) of H-OS-starch compared with the control. The higher the pretreatment temperature was, the more the OSA could go deep into the internal starch granules. The optimal pretreatment temperature for the OSA modification was 60°C. In addition, the OS groups appeared to be distributed throughout the OS-starch granules, especially on the surface, as shown by confocal laser scanning microscopy (CLSM). H-OS-starch had a slightly higher peak viscosity (Pv) and break down (BD) values, but lower pasting temperature (Tp) compared with the control OS-starch.

Preparation, Storage and Distribution of Coated and Uncoated Chicken Meat Products

Abstract The production of coated foods using batters and breading is widespread in various meat, fish and vegetable products including poultry, i.e. chicken meat cuts. Thus, samples of coated and uncoated chicken meat cuts, i.e. leg and breast, fried or baked were applied in this study. Five batter samples as well as a breading coating sample were evaluated against non coated samples for physicochemical and sensory characteristics. The results indicated that batters enriched with protein produced coating systems with increased crispiness and adhesion while batters enriched with modified corn starches resulted in improved product yields. A combination of wheat flours with modified waxy corn starches resulted in products with excellent adhesive properties, desirable thickness, good crispness and appearance. The cooked meat pieces (coated and uncoated) were packaged after cooling in plastic bags and stored at ‒18C for further analysis, i.e. moisture, water activity, thiobarbituric acid (TBA) and pH values. The results showed reduction in moisture and water activity values and increase in pH and TBA values for the tested (coated and uncoated) products at 0, 1, 4, 8, 12, 16 and 24 weeks of testing periods. Sensory evaluation analysis showed a significant preference for the coated samples compared to the uncoated products.

Properties of particleboard made from rubberwood using modified starch as binder

The objective of the study was to evaluate physical and mechanical properties of experimental particleboard panels made from rubberwood (Hevea brasiliensis) using modified starch as binder. Panels were manufactured using 15% corn starch modified with glutardialdehyde and tested for their properties based on Japanese Standard. The modulus of rupture and the internal bond strength of the panels met the requirement of the specified standard. Based on the findings in this work modified corn starch can have a potential to be used as binder to produce particleboard panels with acceptable properties.

Effect of alkali and oxidative treatments on the physicochemical, pasting, thermal and morphological properties of corn starch

Few studies on starch modifications using different chemical agents are available in the literature, and no reports were found on the combined effect of oxidation and alkaline treatment of corn starch. Thus this work evaluated the physicochemical, pasting, morphological, cystallinity and thermal properties of chemically modified corn starch, after either the isolated or combined action of alkaline (sodium hydroxide) and oxidative (sodium hypochlorite) treatments. The highest values for the sum of carbonyl and carboxyl and enzymatic hydrolysis occurred in starches submitted to oxidative treatment at high active chlorine concentrations. The alkali treatment in isolation modified the pasting properties, reduced the paste temperature and increased the peak viscosity, breakdown, final viscosity and setback of starches. Starch modified by the action of sodium hypochlorite and hydroxide in combination presented more severe damage on granule surfaces. The results show that corn starch modified by the combined action of oxidative and alkaline treatments should be studied more, especially at the concentration limit of sodium hydroxide where gelatinization occurs. Under these conditions the effect of oxidation can be more intense and thus allow the production of starches with different properties and an increase in their industrial applications.

Research on starch‐g‐polyvinyl acetate and epoxy resin‐modified corn starch adhesive

AbstractA new corn starch adhesive modified by starch‐g‐polyvinyl acetate (starch‐g‐PVAc) and epoxy resin is described in this study. Starch‐g‐PVAc is used as high cohesive energy component to improve the dry shear strength of the starch adhesive. Although the epoxy resin, which can easily crosslink with the oxidized starch, is used as water‐resistant component to improve the wet shear strength. Because there is no chemical reaction happening between polyvinyl acetate and epoxy resin, both the dry shear strength and the wet shear strength of the corn starch adhesive are notably increased. Considering all the related factors, the optimum of the modification is achieved when the dosage of starch‐g‐PVAc and epoxy resin is 70% of the oxidized starch latex with m(Ep): m(starch‐g‐PVAc) = 1:2. That is, the epoxy resin is 23% in mass fraction and starch‐g‐PVAc 47% in mass fraction. The dry shear strength is 4.50 MPa, and the wet shear strength is 2.51 MPa. The modified corn starch has a broad prospect in the application of plywood industry. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers

The Effect of Selected Starches on Hydration, Textural and Sensory Characteristics of Restructured Beef Products

AbstractWet‐extracted (WEPS) and air‐classified pea starches were included at 3 g/100 g in a restructured beef with 0, 20 or 40 g/100 g water addition. Hydration and textural properties, and consumer acceptance were evaluated, and performance of pea starch‐added products was compared with a product made with modified cornstarch (MCS) and a starch‐free control.The meat protein/starch matrix in the restructured products was sufficient to entrap water during cooking, although the systems were less stable with 40 g/100 g water addition leading to greater moisture losses. Increased moisture content resulted in products with decreased hardness and chewiness. Compared with control, all starches improved hydration properties of the products containing additional water; however, MCS performance was superior to pea starch, especially for purge control.Firmness acceptability of MCS and WEPS samples was lower than that of the starch‐free control; however, starch type did not affect color, flavor or overall acceptability.Practical ApplicationsResults of this study indicate a potential for using pea starches to improve the processing characteristics of restructured meat products. Of the three starches tested, modified cornstarch was found to be superior for controlling purge and improving hydration properties of water‐added products; however, the pea starches still performed better than the control for moisture retention in corned beef.Pea starches could be a viable and a lower‐cost formulation alternative to traditional cornstarches and therefore create new opportunities for extending their utilization in food systems.

Structural and mechanical characteristics of film using modified corn starch by the same two chemical processes used in different sequences

Structure of dual modified starches, cross-linked esterified corn starch (CES) and esterified cross-linked corn starch (ECS), and product films (CEF and ECF) were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction and scanning electron microscopy (SEM). The peak 1730cm−1 of IR spectra confirmed the formation of ester carbonyl groups in starch matrix. The sequence of modification procedure had an impact on the final modification degree, resulting in structural differences of modified starches and starch films. Compared to native starch film (NF), CEF and ECF showed improved transparence (77.59% and 74.39% respectively) with compact structure, lower crystallinity (6.5% and 7.4% respectively). Results of mechanical test indicated that structure of ECF was more flexible than CEF, whereas tensile strength was higher in CEF. Accordingly, complex modification could be an effective method to adequate properties of starch films for specific processing requirements.