Starch Blends Research Articles

Cell walls of extruded pea snacks: Morphological and mechanical characterisation and finite element modelling

Pulses extruded foods can be envisaged asall solid foams with voids and walls, the latter being considered as a dense starch/protein composite. Pea flour (PF) and blends of pea starch and pea protein isolate (PPI) with different protein contents (0.5–88% dry basis) were extruded to obtain models of dense starch-protein composites. Their morphology was revealed by CLSM microscopy, and their mechanical properties were investigated using a three-point bending test complemented by Finite Element Method (FEM) modelling. Composite morphology revealed protein aggregates dispersed in the starch matrix. It was described by a starch-protein interface index Ii computed from the measured total area and perimeter of protein aggregates. The mechanical test showed that the extruded PF and PPI ruptured in the elastic domain, while the extruded starch-PPI (SP) blends ruptured in the plasticity domain. The mechanical properties of pea composites were weakened by increasing the particle volume fractions, including proteins and fibres, probably due to the poor adhesion between starch and the other constituents. The mechanical behaviour of pea composites did not accurately follow simple mixing laws because of their morphological heterogeneity. Modelling results show that the elastoplastic constitutive model using the Voce plasticity model satisfactorily described the hardening behaviour of SP blend composites. Reasonable agreement (2–10%) was found between the experimental and modelling approaches for most materials. The computed Young’s modulus (1.3–2.5 GPa) and saturation flow stress (20–45 MPa) increased with increasing Ii (0.7–3.1), reflecting the increase of interfacial stiffening with the increase of contact area between starch and proteins. FEM modelling allowed to identify the mechanical effect of structural heterogeneities.

Extraction and Characterisation of Avocado Seed Starch, and Its Blend with Enset Cellulosic

Avocado seed starch was extracted to prepare a biodegradable plastic film with enset cellulosic reinforcement and glycerol plasticiser. The characterisations were made in detail. Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimeter (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD), rheometer, and Rapid Visco Analyser (RVA) techniques were employed to characterise the physicochemical properties of avocado seed starch, enset cellulosic, and the blend. Starch and enset cellulosic extraction yields are 18.3 ± 0.02% and 67.5 ± 0.08%, respectively. As a result, avocado seed starch and enset cellulosic blend can be used as alternative raw materials to develop biodegradable plastics.

Development and Characterization of Nutritious Gluten-Free Doughnuts with Lupin and Inulin Flours.

Celiac disease is an immune-mediated disease caused by ingestion of gluten-containing products. The main aim of this study was to develop novel gluten-free doughnuts with high nutritional value using inulin and lupin flour. Five different doughnuts were formulated. Lupin flour was used to replace the potato starch–corn flour composite at levels of 15, 30, 45, 60 and 75% in gluten-free doughnut formulations (AF), (BF), (CF), (DF) and (EF), respectively. Inulin was added to all blends at a level of 6%. Doughnuts made with 100% wheat flour (C1) and 100% corn flour–potato starch blend (C2) served as the controls. The results indicated that the moisture, ash, fat, protein and crude fibre contents of the doughnuts were increased significantly (p < 0.05) with increasing levels of lupin flour. The rheological properties showed that the dough development time increased significantly (p < 0.05) with increasing lupin flour in the formulation with higher water absorption. The consumer acceptability sensory results varied among the different treatments. However, the AF, CF, and EF doughnuts had the highest value for flavour, texture and crust colour, respectively. Different levels of lupin flour can be used in gluten-free doughnuts production to improve their quality and to enhance their nutritional value in the presence of inulin at a 6% level. These results may have significant implications for the development of novel, healthier food products for gluten-sensitive consumers.

Effect of Storage Conditions on the Physicochemical Characteristics of Bilayer Edible Films Based on Iron Yam–Pea Starch Blend and Corn Zein

Edible iron yam–pea starch-based bilayer films with a water and oil proof layer of corn zein were prepared by casting method and stored under normal temperature (25 °C; relative humidity (RH): 43%, 54%, 65%), refrigeration (4 °C) and freezing (−17 °C) for 150 days. The mechanical properties, scanning electron microscope (SEM) micrographs, oxygen and water vapor permeability, color, transmittance, haze, water content were systematically evaluated after 0, 30, 60, 90, 120 and 150 days. The transmittance, haze, and water content of bilayer films changed greatly within 150 days, which indirectly indicated the changes of the internal microstructure of the film matrix. The results were further verified by SEM analysis. Water and oxygen resistance gradually become worse. At 25 °C and 54% RH, the barrier performances were relatively strong. Films had relatively good tensile strength at normal temperature and high humidity, and relatively good elongation at break at low temperature and high humidity. SEM observation showed that there was no interlayer separation during storage. The internal network structure disappeared and reappeared again. The changes of internal microstructure also verified the changes of barrier and mechanical properties of bilayer films.

The Consistency Factor and the Viscosity Exponent of Soybean-Protein-Isolate/Wheat-Gluten/Corn-Starch Blends by Using a Capillary Rheometry.

Blends with different proportions of protein or starch show different rheological behaviors, which may be related to the fibrous structure formation of extruded textured plant proteins. The consistency factor K and the viscosity exponent n of soybean–protein–isolate (SPI)/wheat–gluten (WG)/corn–starch (CS) blends were investigated through capillary rheometry. All blends exhibited shear-thinning behavior at 80 °C and 50% moisture. The CS content in SPI/CS blends or WG content in SPI/WG blends showed a positive relation to the viscosity exponent n and a negative relation to the consistency factor K. However, there was no correlation between the CS content in WG/CS blends and n or K. The coefficient of determination of the linear relationship between K and mass fraction in SPI/CS, SPI/WG/CS, SPI/WG and WG/CS decreased from 0.872 to 0.073. SPI was more likely to form a non-interactive structure, while wheat-gluten was more likely to form a highly interactive structure. It turned out that the materials with globular morphology, such as soybean-protein-isolate and corn-starch, are likely to form a non-interactive structure.

Influence of incorporation of peanut protein isolate on pasting, rheological and textural properties of rice starch

This study investigated the influence of peanut protein isolate (PPI) incorporation in rice starch blends (RS-PPI) in terms of their rheological, textural, and microstructural properties. Among all fitted models in steady-state rheology, the Power-law model had the best fit. Incorporation of PPI improved storage modulus (G′) and loss modulus (G″) but decreased the limiting strain of the linear visco-elastic region. In the frequency sweep study, G′ and G″ increased with PPI addition for the samples containing high starch ratios, whereas the opposite trend was observed for the samples containing low starch ratios. The stress relaxation curves fitted reasonably well with the Peleg model (R2 > 0.995), and the initial and equilibrium force obtained followed the same trend as hardness values obtained from the TPA study. Initially, PPI addition to RS formed an interactive gel network showing honeycomb-like features, but further addition of PPI led to a formation of a non-homogeneous network.

Pasting and gelation behaviors and in vitro digestibility of high-amylose maize starch blended with wheat or potato starch evaluated at different heating temperatures

Different approaches have been adopted to overcome the inherent shortcomings of native starches, and blending of different native starches has attracted much attention due to the “clean-label” feature and the low processing effort and cost. In the current study, we blended high-amylose maize starch (HA7) with wheat (WHE) or potato (POT) starch at 1:1 ratio (dry weight basis; dwb) and then comprehensively examined their thermal properties, pasting and gelling behaviors over the heating temperature range of 95–140 °C, and in vitro digestibility in comparison with three individual starches. With an excess amount of water (starch:water = 1:3), gelatinization of individual starches generally appeared to be independent in the two starch blends. An exceptionally low percentage of retrogradation was observed for gelatinized HA7-WHE blend during cold storage, which could be partially ascribed to the formation of a large amount of amylose-lipid complexes (ALC). Greater resistance to thermal degradation and thixotropic breakdown during pasting at 120 °C was found with HA7-WHE blend when compared with HA7-POT blend. Both starch blends could form gels with moderate strength (74.3–109.4 g) after cooking at 120 and 140 °C. The determined resistant starch (RS) and slowly digestible starch (SDS) contents of water-boiled HA7-WHE blend were higher than the calculated values when assuming simple additivity of the two starches. The interactions at both granular and molecular levels and the presence of ALC were responsible for the reported unique techno-functional attributes of HA7-WHE blend, which rendered it suitable for diverse food and industrial applications. • More amylose-lipid complex in high-amylose (HA7)-wheat (WHE) starch blend (1:1 dwb). • Gelatinized HA7-WHE blend had the least %retrogradation (9.2%) of all the starches. • HA7-WHE blend showed strong resistance against high-temperature cooking at 120 °C. • Starch blends had moderate gel strength (74.3–109.4 g) after 120 and 140 °C cooking. • Water-boiled HA7-WHE blend showed enhanced in vitro enzymatic resistance.

Effect of surfactant content on rheological, thermal, morphological and surface properties of thermoplastic starch (TPS) and polylactic acid (PLA) blends

Miscibility in biopolymeric blends is a critical process that requires evaluation of the effect of surfactants or coupling agents under conditions similar to processing. Different mixtures in the molten state of plasticized starch and polylactic acid in the presence of a surfactant (Tween 20) at different concentrations were studied. This allowed knowing the rheological, thermal and surface behavior of the mixtures. The results of the dynamic rheological analysis showed increases in viscosity in the presence of the surfactant, in which strong interactions were produced at high shear rates that reflect possible crosslinking between the polymer chains, in addition to intermolecular interactions that were evidenced in the infrared spectrum. Likewise, the storage and loss modulus showed transitions mainly from viscous to elastic typical for thermoplastics. The thermogravimetric analysis did not show significant changes between the mixtures. However, the calorimetric analysis showed changes in the crystallinity of the mixtures, the tensoactive promotes greater freedom of movement and rearrangements in the microstructure with decrease of interface between polymers, and less compaction of the material induced by the emulsion. Analysis derived from biopolymeric films against contact with water shows significant changes. Interaction with water in short times (in the order of minutes) according to the sessile drop technique, favors hydrophilicity by increasing the concentration of Tween 20. However, interaction with water for prolonged times (in the order of hours), shows that the absorption reaches saturation in samples a stabilization in the absorption is observed. The results demonstrate that the miscibility of PLA in AS was achieved in the presence of the tween, under conventional processing conditions. The stability of the different formulations allows the production of films for packaging and biomedical applications.

The gastrointestinal and microbiome impact of a resistant starch blend from potato, banana, and apple fibers: A randomized clinical trial using smart caps.

The gastrointestinal (GI) impact of fibers including resistant starch (RS) consumption depends on various types and amounts of fibers, the initial microbiome states, and accurate intake measurements. A randomized clinical trial evaluated the GI impact of varying doses of a novel resistant starch blend (RSB) with smart cap monitoring. RSB contained at least 50% RS and was a proprietary mixture of a potato starch, green banana flour, and apple fiber powder (a source of apple pectin, not resistant starch). The study design randomized participants to one of four arms: 10 g/day of potato starch (0 RSB), 10 g/day of RSB, 10 to 20 to 20 g/day of RSB or 10 to 20 to 30 g/day RSB for two-week intervals over 6 weeks. Results confirmed that while resistant starch of approximately 5 g per day improves GI symptoms at 2, 4, and 6 weeks, it did not demonstrate a detectable effect on short chain fatty acids. Increasing doses of the blend (RSB) led to a decrease in the diarrhea score. Using an estimate of total consumption of RSB based on smart cap recordings of container openings and protocol-specified doses of RSB, a reduction in the sleep disturbance score was associated with higher RSB dose. The exploratory microbiome evaluation demonstrated that among the 16S rRNA gene sequences most associated with the consumption of the novel blend RSB, two belong to taxa of notable interest to human health: Faecalibacterium and Akkermansia.

Evaluation of carboxylic acids as sustainable compatibilizing agents on blend sheets properties based on thermoplastic babassu starch and polypropylene

Polypropylene/babassu thermoplastic starch (PP/TPS, 70:30 w/w) blend sheets were prepared as an alternative material to use in disposable packaging, reducing the negative environmental impact of synthetic polymer. Three different carboxyl acids: palmitic (PP/TPS/P), citric (PP/TPS/C), and stearic (PP/TPS/S), were used as natural compatibilizing agents (NCA) and compared to the conventional synthetic maleic anhydride (PP/TPS/M), concerning mechanical, physical, crystallinity, and morphological properties of the blend sheets. The blend sheets without or with compatibilizing agents resulted in dark coloration, higher opacity, higher thickness, lower resistance to break, flexibility and rigidity, higher moisture, solubility in water, hydrophilicity, lower crystallinity, and more heterogeneous morphology in comparison to PP sheets. The presence of compatibilizing agents was observed to improve the mechanical and physical properties of the blend sheets, resulting in materials stronger and less hydrophilic. The citric acid was able to act similarly to the synthetic maleic anhydride, resulting in blend sheets with similar mechanical and physical properties. Finally, this work shows that the natural compatibilizing agent citric acid was analogous to the commercial one, synthetic maleic anhydride, bringing a more sustainable alternative. In addition, this work allowed assessing a new source of starch and offering one more alternative for applying this source to the plastic packaging sector.

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.

Evaluation of Cassava (Manihot esculenta) and Sweet Potato (Ipomea batatas) Starch from South East Nigeria in the Separation of Deoxyribonucleic Acids as Alternative to Agarose Gel

Gel electrophoresis technique is an indispensable tool in biotechnology and among other related fields for separation of nucleic acids and proteins. This study determined the potential of selected cassava and sweet potato starch in the separation of DNA as alternative to agarose gel. The sample pH, gelling temperature and time were determined by Light transmittance method proposed by Craig et al. [1] Standard electrophoresis procedure was used for the starch gel electrophoresis. The result showed that composite starch gelled within 18-21 minutes while agarose and agar-agar gelled after 12 minutes. Cassava starch blended with agar-agar gelled at a temperature of 58oC while sweet potato starch blended with agar-agar gelled between 35oC - 47oC. Agarose and agar-agar maintained 54oC and 53oC respectively. There was no significant difference (P &gt; 0.05) in pH value of the composite starch when compared to 1% agarose gel. Unblended starch samples did not form solid gel except when blended with some amount of agar-agar or agarose powder. Cassava and sweet potato composite starch formed good gel strength at 3% (2.2 g of starch and 0.8 g of agar-agar) but solid gel at 4% (3.6 g of starch and 0.8 g of agar-agar). This study demonstrated the possibilities for agarose cost reduction by 60% when cassava starch (3.6 g) was blended with 0.4 g of agarose. The cassava composite starch (4%) separated DNA molecules comparably to that of 1% agarose. Therefore, the use of these cheaper, accessible and readily available blended starch sources is highly recommended for separation of biomolecules such as DNA.

Characterization, biodegradation and cytotoxicity of thermoplastic starch and ethylene-vinyl alcohol copolymer blends

Ethylene-vinyl alcohol samples containing 27 and 38 % ethylene were used to prepare blends containing 30 and 50 % thermoplastic starch (TPS) plasticized with glycerol. Their biodegradability and cytotoxicity were studied by different techniques (XRD, DSC, TGA, CA, ATR-FTIR, SEM). TPS presence significantly affected copolymer behavior, as confirmed by the appearance of OH IR 1000–1170 cm−1 bands and overall reduction of EVOH crystallinity, melting point, thermal stability and hydrophobicity. Biodegradation was more efficient in the presence of TPS and resulted in the formation of a robust biofilm by a consortium of three bacteria. A lower ethylene content facilitated biodegradation, making the material easier to metabolize. The mineralization percentages obtained after a 40-day bioassay at 45 °C were up to 66 % (EVOH-27/TPS 50:50). In vitro cytotoxicity assay demonstrated no cytotoxicity before and after biodegradation. EVOH/TPS blends are presented as a potential environmentally friendly alternative to pure synthetic polymers.

PRODUCTION AND QUALITY EVALUATION OF READY TO EAT EXTRUDED SNACKS FROM FLOUR BLENDS OF ACHA-COWPEA AND SWEET POTATO STARCH

Acha is a potential food security crop that contributes significantly to people’s diet, especially in developing countries such as Nigeria. The suitability of acha-cowpea composite flour and sweet potato starch in the production of extruded snacks was investigated. Acha flour (ACF), cowpea flour (CPF)and sweet potato starch (SPS),were mixed in various proportions of percentage weights (ACF:CPF:SPS)and were used to produce extruded snacks totaling 7 samples: 100:0:0, 90:5:5, 85:5:10, 75:5:20, 70:5:25:, 65:5:30 and50:0:50.The flour blends and starch mixes were analyzed for functional properties while the extruded snacks were evaluated for proximate, physicochemical and sensory properties. There was significant differences (p&lt;0.05) in the functional properties of the flour and starch blends. Oil and water absorption capacity reduced as the proportion of SPS increased while the wettability followed the same trend. Foam capacity and foam stability were higher in all the blends containing cowpea flour. Gelatinization temperature was highest in blends with equal proportions of acha and sweet potato starch.The proximate composition of the extruded snacks were significantly difference (p&lt;0.05) amongst the samples. The result showed that all the samples with cowpea flour had higher protein and ash contents than the control. Samples with 90% AF, 5% SPS and 5% CF performed best in sensory scores particularly in terms of appearance, taste, texture and general acceptability. However, all the samples were generally accepted. It was concluded that nutritious extruded snacks with acceptable sensory qualities can be produced from blends of acha-cowpea flour and sweet potato starch.

Extrusion of pea snack foods and control of biopolymer changes aided by rheology and simulation

Pea flour and a blend of pea starch and protein isolate with a starch-to-protein ratio close to 2/1 were processed using co-rotating twin-screw extruders. Different extruder scales operated at a moisture content of 18–35% and a screw speed of 120–700 rpm resulted in large intervals of melt temperature T (95–165 °C) and specific mechanical energy SME (150–2000 kJ/kg). With increasing T and SME, starch solubility in water increased due to starch melting and depolymerisation, and protein solubility in SDS decreased due to formation of protein aggregates linked by disulphide bonds. Extruded foods’ morphology was studied by CLSM. Protein cross-linking increased the median size of protein aggregates; starch destructuration increased the area of the starch phase to the detriment of the protein one. Melt shear viscosity was determined using a pre-shearing capillary rheometer. The melts exhibited shear-thinning behaviour according to a power-law model, with values close to those of model parameters observed for pea flour and SP 2/1 blend. The rheological model was implemented in a 1D global extrusion model to simulate pea ingredient extrusion. Satisfactory correlations between predicted extrusion variables (T, SME) and biopolymer transformation suggested that products with target structure can be obtained using simulation to tune extrusion conditions.

Effect of Interphase Properties on Isothermal and Non-isothermal Crystallization Behavior of Poly(lactic acid)/Acetylated Starch Blends.

The effect of interphase properties on the crystallization behavior of blends of poly(lactic acid) (PLA)/acetylated starch (AS) with different degrees of substitution (DSs) was investigated. Under isothermal crystallization conditions, the rate of crystallization was higher for PLA/DS0.5 and lower for PLA/DS1.5 and PLA/DS2.5 when compared to PLA. In contrast, non-isothermal crystallization behavior indicated a slower rate of crystallization of PLA/DS0.5 and a faster rate of crystallization of PLA/DS1.5 and PLA/DS2.5 compared to PLA at the highest cooling rate (5 °C/min). The potential relationship between crystallization behavior and interphase properties and interphase thickness and formation of rigid amorphous fraction in the interphase, was investigated. The formation of a rigid amorphous fraction in PLA/DS1.5 and a thick interphase in PLA/DS2.5 prevented the formation of crystals on the dispersed phase and interrupted the crystallization under isothermal conditions. Hydrogen bonding in the PLA/DS1.5 blend and hydrophobic interactions in the PLA/DS2.5 blend may facilitate the crystallization at high cooling rates under non-isothermal conditions. Small-angle X-ray scattering analysis revealed the presence of a smaller lamellar structure in PLA/AS blends. The largest amorphous phase among blends was observed for the PLA/DS1.5 blend, which can be attributed to the hydrogen bonding in the interphase region of this blend.

Preparation of green film with improved physicochemical properties and enhanced antimicrobial activity using ingredients from cassava peel, bamboo leaf and rosemary leaf

Persistent petroleum based plastic polymers are posing a threat to the environment and human health. Hence, preparation of eco-friendly packaging materials from natural sources is innovative idea to replace persistent plastic films. However, biodegradable films from biomass absorb water that can promote bacterial growth and affect lifetime of film as well as the packed products. In this work, new biodegradable film with improved antimicrobial activity, physicochemical property and less water absorbing and holding property is prepared from modified blend of cassava peel starch (CPS), silica nanoparticle (SNP), glycerol plus rosemary essential oil (REO). The mixture (blend) of CPS, SNPs and glycerol in measured amount of distilled water was treated with acetic anhydride to reduce hydrophilic nature of the blend before adding REO. The content of SNPs in the biofilm was optimized by varying the concentration of SNPs (0.2–0.8%; w/w) keeping other factors constant. Based on the characterization results, the physicochemical property of the biofilms was dependent on the content of SNPs and the best result (film) has been found with 0.6% SNPs which was considered as optimum amount for further experiments. The film prepared from modified blend with 0.6% SNP had shown low water absorption, low water vapor transition rate, improved thermal stability, and less biodegradability. Based on the image from profilometer, the modified blend had shown better homogeneity with REO than unmodified blend and the film with REO had shown better antimicrobial activity as compared to the film without REO (control). The antimicrobial activity of the film with REO was also compared with reference (gentamicin) and its activity was comparable and promising. In general, the prepared film had shown improved physicochemical properties and enhanced antimicrobial activity.

Synthesis and detailed characterization of sustainable starch‐based bioplastic

AbstractThere is an urgent requirement of replacing the environmentally hazardous petroleum‐based plastics with sustainable and efficient starch‐based bioplastics. Development and detailed characterization of the biodegradable bioplastics from plant‐based polysaccharides such as starch is essential to reduce plastic pollution in the environment. In this research, bioplastics were developed from an equivalent blend of starch from two different sources namely rice and potato (1:1, w/w), crosslinked with different concentrations of citric acid (CA). The effect of CA cross‐linking of starch‐based bioplastics was investigated on its physicochemical and functional properties. The X‐ray diffraction (XRD) spectra revealed that the synthesized bioplastics were amorphous in nature with broad diffraction peaks. Further, the peak at 1716 cm−1 in Fourier transform infrared (FTIR) spectra indicated the formation of ester bonds in CA cross‐linked bioplastics. Atomic force microscopy (AFM) revealed the surface roughness of the bioplastics decreased with increasing concentration of CA. Mechanical and thermal properties of bioplastics were characterized using universal testing machine, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), respectively.

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.

Recent Developments in Starch Modification by Organic Acids: A Review

AbstractTreatment or processing of starch with organic acids (citric, stearic, succinic, and malic acids) can be used to obtain starch properties like low retrogradation, desirable viscosity, shear resistance, and high resistant starch. Esterification, cross linking, and hydrolysis of starch may occur after modification with organic acids (citric, succinic acid, malic acid) whereas a complex between starch and stearic acid may be formed on use of stearic acid. The conditions of reactions namely duration, starch acid concentration ratio, and temperature may influence physicochemical and structural properties of starch. Citric acid, succinic acid, stearic acid, and malic acid are regarded as "GRAS" and thus the starch citrate, starch succinate, starch stearate, and starch maleate are widely used in manufacturing of starch films, blends, nanoparticles, fat replacer, viscosity enhancer, and many other products. This review paper discusses the reaction conditions of organic acid modification of starches along with their influence on physicochemical and structural characteristics.