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Defatted chickpea flour (DCF), a rich source of protein and starch, is frequently utilized in the food industry. Two crucial methods of modifying food materials are high-pressure homogenization (HPH) and heat treatment (HT). This study investigates the effect of co-treatment (HPH-HT) on the particle size, rheological behavior, and thermal characteristics of DCF suspensions. The results indicate that both HPH and HT can result in a more uniform distribution of particle size in the suspensions. The effect of HPH on G′ was observed to be reductionary, whereas HT increased it. Nevertheless, the HPH-HT treatment further amplified G′ (notably in high-concentration DCF), which demonstrates that the solid properties of DCF are improved. The apparent viscosity of the suspensions increased with individual and combined treatments, with the HPH-HT treatment of DCF12% exhibiting the most significant increase (from 0.005 to 9.5 Pa·s). The rheological behavior of DCF8% with HPH-HT treatment was found to be comparable to that of DCF12% treated only with HT. In conclusion, HPH-HT treatment shows a synergistic impact of HPH and HT on the rheological properties of DCF suspensions, however, it has limited effect on the particle size distribution and freeze–thaw stability.

High-amylose maize starch (HAS) was used to produce a fibrous 3D network nanosystem aiming at providing an efficient and stable emulsion stabilizer characterized by being robust against storage, freeze-thawing, high temperatures and mechanical shearing. This approach is principally different from the usually applied stabili-zation systems based on surfactants or small solid particles. Here, we utilized a sodium hydroxide-based low -temperature, chemical gelatinization protocol to minimize molecular degradation, and ethanol nanoprecipitation to reassociate the polysaccharides nanoparticles (NPs) to form a 3D nanosystem. Octenyl succinic anhydride (OSA) substitution was used for modulation of the amphipathic properties of the nanosystem to enhance the emulsfying capacity. With increased OSA substitution, light transmittance of the NPs solutions increased and the size distribution of the NPs decreased down to 100 nm. The obtained emulsions were characterized by being water in oil (W/O) systems, and the NPs were distributed in the oil phase. OSA substitution and NPs concen-tration contributed combinedly to the emulsification capacity. The nanosystem, at 5% concentration with 20% OSA modification, had droplets of approximately 1 mu m in diameter, and could withstand a 60-day-long storage, five-cycle freeze-thaw and thermal stability tests. In addition, it also displayed higher mechanical stabilities to shear-thinning.

In order to evaluate the freeze-thaw stability of mung bean protein isolate (MPI)-stabilized emulsions and its relationship with protein structure, proteins of eight mung bean varieties were compared. The results revealed that MPIs prepared from all eight varieties were mainly composed of five subunit bands, with albumin and globulin content ranges of 188.4–310.3 and 301.1–492.7 mg/g total protein, respectively. Protein structural analysis revealed that random coil structure (32.34–33.51%) accounted for greater than 30% of MPI secondary structure. Meanwhile, analysis of protein properties revealed emulsifying activity index (EAI), emulsifying stability index (ESI) and flexibility value ranges of 6.735–8.598 m2/g, 20.13–34.25% and 0.125–0.182, respectively. Measurements of freeze-thaw stability of MPI emulsions demonstrated that exposures of emulsions to multiple freeze-thaw cycles resulted in significantly different emulsion creaming index, oiling-off, particle size and zeta potential values for the various emulsions. Moreover, the stabilities of all eight protein emulsions decreased with each freeze-thaw cycle, as demonstrated using optical micrographs. The correlation analysis method was used to study the correlation between the original structures, emulsifying properties of proteins and the freeze-thaw stability of MPI emulsions. Correlation analysis results revealed significant relationships between albumin content, subunit bands with a molecular weight of 26.9 kDa and emulsifying properties were significantly related to the freeze-thaw stability of MPI emulsion. Thus, by determining these indicator values, we can predict the freeze-thaw stability of MPI-stabilized emulsions.

Trypsin is a serine protease with important applications such as protein sequencing and tissue dissociation. Preserving protein structure and its activity during freeze-thawing and prolonging its shelf life is one of the most interesting tasks in biochemistry. In the present study, trypsin cryoprotection was achieved by altering buffer composition. Sodium phosphate buffer at pH 8.0 led to pH shift-induced destabilization of trypsin and formation of a molten globule, followed by significant activity loss (about 70%). Potassium phosphate and ammonium bicarbonate buffers at pH 8.0 were used with up to 90% activity recovery rate after 7 freeze-thaw cycles. The addition of non-ionic surfactants Tween 20 and Tween 80 led to up to 99% activity recovery rate. Amide I region changes, corresponding to specific secondary structures in the Fourier transform infrared (FTIR) spectrum, were modest in the case of Tween 20 and Tween 80. On the other hand, the addition of Triton X-100 led to the destabilization of α-helicoidal segments of trypsin structure after 7 freeze-thaw cycles but also increased protein substrate availability.

Cross-linked esterified starch (CES) was prepared using a one-step method, where maize starch was selected as the raw material, sodium trimetaphosphate as the cross-linking agent, and acetic anhydride as the esterifying agent, respectively. A response surface experiment was systematically conducted for analyzing the correlation of the experimental variables (cross-linked temperature, pH, reaction time, sodium trimetaphosphate and acetic anhydride dosage) and properties of the product (peak and final viscosity). The Brabender viscosity, freeze-thaw stability, shearing resistance, and acid tolerance of the cross-linked acetylated dual modified starch were studied under different conditions of crosslinking degree and acetyl content. Meanwhile, the granular structure and morphology of the modified starch were analyzed. The results indicated that: after cross-linked acetylated dual modification, the starch had a distinct birefringence and granular structure, along with the creation of new carbonyl groups. The low degree of crosslinking and high acetyl contents were beneficial to the viscosity, which was significantly increased at both low and high temperatures. Moreover, the freeze-thaw stability of CES was elevated sharply after five cycles. In addition, CES displayed increased shear and acid tolerance compared to the original waxy maize, and their lowest differences between waxy maize and CES were only 0.62% and 0.59%, respectively. In summary, a novel method for starch modification was provided, and the synthesized CES was suggested to have exceptional performance for the food industry.

The main objective of this study was to investigate the effect of different oil phase compositions (medium-chain triglyceride (MCT) and long-chain triglyceride (LCT), the proportion of MCT is 0%, 5%, 10%, 15% and 20%, respectively) on the rheological properties and freeze-thaw stability of emulsions. The emulsions were characterized by differential scanning calorimetry (DSC), rheometer, stability analyzer, Malvern particle size meter and confocal microscope. Results showed that all emulsions exhibited a gel-like characteristic with a storage modulus higher than the loss modulus. The elastic modulus and complex viscosity of the emulsions increased with the increase of MCT proportions. During the heating from 4 °C to 80 °C, the complex viscosity of all emulsions decreased first and then remained unchanged at a continuous high temperature, indicating that the emulsions had good stability and internal structural integrity during the cooling and high-temperature processes. With the increase of MCT proportions, the freeze-thaw stability of the emulsions increased first and then decreased, and showed the optimum with 10% MCT. That could be referred for the production of a product with better freeze-thaw stability and rheological property in the food and cosmetic industries.

There is growing interest in enhancing the freeze–thaw stability of a Pickering emulsion to obtain a better taste in the frozen food field. A Pickering emulsion was prepared using a two-step homogenization method with soybean protein and maltose as raw materials. The outcomes showed that the freeze–thaw stability of the Pickering emulsion increased when prepared with an increase in soybean protein isolate (SPI) and maltose concentration. After three freeze–thaw treatments at 35 mg/mL, the Turbiscan Stability Index (TSI) value of the emulsion was the lowest. At this concentration, the surface hydrophobicity (H0) of the composite particles was 33.6 and the interfacial tension was 44.34 mN/m. Furthermore, the rheological nature of the emulsions proved that the apparent viscosity and viscoelasticity of Pickering emulsions grew with a growing oil phase volume fraction and concentration. The maximum value was reached in the case of the oil phase volume fraction of 50% at a concentration of 35 mg/mL, the apparent viscosity was 18 Pa·s, the storage modulus of the emulsion was 575 Pa, and the loss modulus was 152 Pa. This research is significant for the production of freeze–thaw resistant products, and improvement of protein-stabilized emulsion products with high freeze–thaw stability.

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 &lt, 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.

Improving the gel texture and stability of rice starch (RS) by natural hydrocolloids is important for the development of gluten-free starch-based products. In this paper, the effects of guar gum and locust bean gum on the pasting, rheological properties, and freeze–thaw stability of rice starch were investigated by using a rapid visco analyzer, rheometer, and texture analyzer. Both gums can modify the pasting properties, revealed by an increment in the peak, trough, and final viscosities, and prevent the short-term retrogradation tendency of RS. Dynamic viscoelasticity measurements also indicated that the starch–gum system exhibits superior viscoelastic properties compared with starch alone, as revealed by its higher storage modulus (G′). Compared with the control, the hysteresis loop area of the guar gum-containing system and locust bean gum-containing system was reduced by 37.7% and 24.2%, respectively, indicating that the addition of gums could enhance shear resistance and structure recovery properties. The thermodynamic properties indicated that both gums retard short-term retrogradation as well as long-term retrogradation of the RS gels. Interestingly, the textural properties and freeze–thaw stability of the RS gel were significantly improved by the addition of galactomannans (p < 0.05), and guar gum was more effective than locust bean gum, which may be due to the different mannose to galactose ratio. The results provide alternatives for gluten-free recipes with improved texture properties and freeze–thaw stability.

The aim of this work was to develop a food-grade emulsion that stabilized by the by-product proteins in the head of giant freshwater prawn. The physicochemical properties of protein particles were characterized, and the stability of proteins-stabilized emulsions under different environmental stresses was evaluated. Results showed that the proteins were relatively hydrophilic and preferentially resided in the aqueous phase to form oil/water emulsions. On this basis, the proteins exhibited superior ability to stabilize the emulsions, and remarkably, the emulsions stabilized by 2% proteins and 3:7 oil/water ratio efficiently resisted the freeze-thaw treatment and the change of pH (3–9), salt addition (NaCl, 50–400 mM), and storage temperatures (4–60°C). Furthermore, the emulsions showed a matched long-term stability with the existing biopolymers-stabilized emulsions. Consequently, this is the first finding of the by-product proteins in the head of giant freshwater prawn as an excellent emulsifier to stabilize emulsions, which help to improve the stability of food-grade emulsions and the added value of aquatic products.

Cassava starches processed from six different cassava varieties (Bangweulu, Katobamputa, Mweru, Kariba, Kampolombo and Chila) were assessed for variety effect on swelling, solubility, gelatinization, pasting and gel freeze-thaw stability properties. The swelling power was investigated using dispersion methods in water while gelatinization and pasting were determined using Differential Scanning Calorimetry and Rapid Visco Analyzer, respectively. The gel freeze-thaw stability was determined by syneresis method. The starch granules size of the cassava starches were in the range 1.17–22.22 μm. The swelling power and solubility index of starches were in the range of 2.22–15.63 g/g and 1.62–71.15%, respectively. Solubility index of starches correlated positively with amylose (p < 0.0001). Swelling powers of starches showed a weak negative correlation with resistant starch content. The onset (To), peak (Tp) and conclusion (Tc) gelatinization temperatures of cassava starches were ranged from 56.33–63.00 ℃, 62.00–71.29 ℃ and 69.10–77.12 ℃, respectively and varied among cassava varieties (p < 0.05). The pasting temperatures for starches were in the range of 64.54–70.54 ℃ and weak positively correlated with amylose (r = 0.231, p < 0.001). The peak viscosity (782.3–983.5 cP), breakdown viscosity (383.8–506.8 cP) and final viscosity (462.0–569.7 cP) varied (p < 0.05) among cassava varieties and exhibited negative correlation with amylose (p < 0.05, p < 0.01, and p < 0.01, respectively). The syneresis for the freeze-thaw and five freeze-thaw cycle storage were ranged from 0.00–29.11% and 0.00–42.40%, respectively, and varied (p < 0.05) among cassava varieties. The sources of variations in physicochemical properties among the cassava varieties were due to differences in amylose, protein, lipid contents, and starch granule size distribution.

The aim of this work was to develop a food-grade emulsion that stabilized by the by-product proteins in the head of giant freshwater prawn. The physicochemical properties of protein particles were characterized, and the stability of proteins-stabilized emulsions under different environmental stresses was evaluated. Results showed that the proteins were relatively hydrophilic and preferentially resided in the aqueous phase to form oil/water emulsions. On this basis, the proteins exhibited superior ability to stabilize the emulsions, and remarkably, the emulsions stabilized by 2% proteins and 3:7 oil/water ratio efficiently resisted the freeze-thaw treatment and the change of pH (3–9), salt addition (NaCl, 50–400 mM), and storage temperatures (4–60°C). Furthermore, the emulsions showed a matched long-term stability with the existing biopolymers-stabilized emulsions. Consequently, this is the first finding of the by-product proteins in the head of giant freshwater prawn as an excellent emulsifier to stabilize emulsions, which help to improve the stability of food-grade emulsions and the added value of aquatic products.

The objective of this study was to determine the effects of rice residue on the physicochemical properties of silver carp surimi gels. The whiteness of gels was slightly decreased when rice residue was added. Breaking force and deformation of gels were significantly decreased with more than 1% rice residue addition (p

The use of unmodified starch in frozen foods can cause extremely undesirable textural changes after the freeze-thaw process. In this study, using cyclodextrin glucanotransferase (CGTase) and branching enzymes, an amylopectin cluster with high freeze-thaw stability was produced, and was named CBAC. It was found to have a water solubility seven times higher, and a molecular weight 77 times lower, than corn starch. According to the results of a differential scanning calorimetry (DSC) analysis, dough containing 5% CBAC lost 19% less water than a control dough after three freeze-thaw cycles. During storage for 7 days at 4 °C, bread produced using CBAC-treated dough exhibited a 14% smaller retrogradation peak and 37% less hardness than a control dough, suggesting that CBAC could be a potential candidate for clean label starch, providing high-level food stability under repeated freeze-thaw conditions.

The aim of this work was to compare the composition and physicochemical properties (SEM, XRD, solubility, swelling power, paste clarity, retrogradation, freeze&ndash, thaw stability, thermal property, and pasting property) of three Chinese yam (Dioscorea opposita Thunb.) starches (CYYS-1, CYYS-2, and CYYS-3) in Yunlong town, Haikou, Hainan Province, China. Our results show that all the CYYS gave a typical C-type X-ray diffraction pattern. The swelling power of CYYS varied from 10.79% to 30.34%, whereas solubility index was in the range of 7.84&ndash, 4.55%. The freeze&ndash, thaw stability of each CYYS showed a contrary tendency with its amylose content. In addition, CYYS-3 showed the highest To (81.1 &deg, C), Tp (84.8 &deg, C), Tc (91.2 &deg, C), and &Delta, H (14.1 J/g). The pasting temperature of CYYS-1 increased significantly with sucrose addition. NaCl could inhibit the swelling power of CYYS. There were significant decreases in pasting temperature and pasting time of CYYS when pH decreased.

The emulsion stabilization functionality of surfactants and biopolymers can be replaced by solid particles adsorbed at the interface, where they create a category of emulsions known as Pickering emulsions. Recently, health and environmental concerns have led to new market demand for natural, biodegradable and renewable sources of ingredients. Starch granules meet these ingredient requirements and are also good candidates for stabilization of Pickering type emulsions due to their properties such as neutral color, taste, odor and being non-allergic. Starch granules are generally hydrophilic and in order to improve their emulsifying capacity they are modified with hydrophobic groups. The most widely used chemical modification is esterification with acid anhydride, such as octenyl succinic anhydride (OSA). Emulsions stabilized by OSA modified starch have shown to have high stability. Moreover, the application of a heat treatment can induce a partial gelatinization of the starch at the oil-water interface, which leads to changes in interfacial properties of the starch granule stabilized emulsions. This thesis focuses on the development and application of starch Pickering emulsions and has been carried out along three main lines of investigation where each line has its own section in the thesis. In the first section, the preparation and properties of oil-in-water emulsions stabilized by starch granules with small sizes, including quinoa, rice and amaranth, were investigated. In the second section, the process and encapsulation stabilities of the emulsions were evaluated in the context of simple oil-in-water and double water-in-oil-in-water emulsions, with or without heat treatment. In the third section, the physical and encapsulation stabilities of the emulsions during in vitro digestion were evaluated. Quinoa starch granules showed to have higher emulsifying efficiency both in the initial state and after accelerated stability testing. Moreover, the heat induced gelatinized layer showed to not only contribute to initial general stability, but also increased the process and encapsulation stabilities of the emulsions. Modified starch granules appeared to protect the emulsions against destabilization mechanisms during processing (i.e. freezing and freeze-drying). It was possible to create powders from starch stabilized Pickering emulsions with high oil content (up to 80%). Furthermore, emulsions stabilized by starch granules showed high stability for encapsulation of bioactive compounds during in vitro digestion. The results of this work can be used for the development of lipid-based encapsulated systems, in both liquid and powder forms for the delivery of bioactive compounds in food, pharmaceutical and cosmetic applications.

International audience; The aim of the study was to show that the presence of a small quantity of konjac glucomannan (KGM) in potato starch suspension increased the stability of carvacrol trapping.For that purpose, several freeze-thaw cycles were used to accelerate the ageing of the product and consequently drastically destabilize the gels, and induce syneresis. The stability of carvacrol trapping was evaluated by the quantification of carvacrol in the syneresis liquid. The stability of the starch gel structure was studied at microscopic and macroscopic scale.The moment of the addition of carvacrol and the presence of KGM both had an effect on the stability of carvacrol trapping and of the structure of the gel.KGM promoted amylose retrogradation but slowed down amylopectin retrogradation. The stability of potato starch gels can be improved by the addition of a small quantity of KGM which showed a 'cryo-protectant' behaviour.New method to characterize the micro and macrostructure from SEM images processing has also been proposed. The processing of microscopy images was done using Generalized Fourier Descriptors and allowed the characterization of each sample. The carvacrol addition lowered the physical stability of the gel with larger pores and increased syneresis. On the contrary, the KGM addition increased the size of the pores but prevented the formation of very large pores and reduced syneresis. The most stable system was obtained by the addition of carvacrol at the end of heating, in a konjac glucomannan potato starch gel.

Starch phosphate esters are crucial in starch metabolism and render valuable functionality to starches for various industrial applications. A potato glucan, water dikinase (GWD1) was introduced in tubers of two different potato genetic backgrounds: an amylose-containing line Kardal and the amylose-free mutant amf. In both backgrounds, this resulted in two contrasting effects, a number of plants showed higher phosphate content compared to the respective control, while others lines exhibited lower phosphate content, thereby generating two series of starches with broad-scale variation in phosphate content. The results of systematic analyses on these two series of starches revealed that starch phosphate content strongly influenced starch granule morphology, amylose content, starch fine structure, gelatinization characteristics and freeze-thaw stability of starch gels. Further analyses on the expression level of genes involved in starch metabolism suggested that starch phosphorylation regulates starch synthesis by controlling the carbon flux into starch while simultaneously modulating starch-synthesizing genes.

The freeze-thaw stability of oil-in-water emulsions prepared with unheated and heated aqueous dispersions of fresh and stored soy protein isolates was evaluated in the absence and presence of glucose or sorbitol (0.75–15.0% w/w). Sample aging had a negative impact of freeze-thaw stability. The cryoprotectant addition enhanced the freeze-thaw stability, but at low concentrations emulsions prepared with unheated soy protein isolates showed better response to freeze-thawing. Nevertheless, at the highest cryoprotectant concentration, a total stabilization was evidenced for all emulsions. The results of this article indicated that the cryoprotectants act on proteins at interfacial level., Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo en Criotecnología de Alimentos

Some properties of cassava and cocoyam starches were studied and compared with a view to determining the functional applications in food systems for which they are suitable. The starches were compared in terms of their microscopic, thermal, physicochemical and rheological properties. Microscopy revealed smaller granule sizes of cocoyam starch compared with cassava. The amylose content was higher in cocoyam starch (33.3%) than in cassava starch (29.3%). Gelatinization in cassava starch occurred at a lower temperature range (60.11 o -72.67oC) compared with cocoyam (72.96o – 80.25oC) with the endothermic gelatinization enthalpy higher in cocoyam. The swelling power and solubility patterns indicated lower relaxation temperature, higher swelling and solubilization rates in cassava starch compared with cocoyam starch. The pasting characteristics of 8% (db, dry basis) starch slurry showed that cassava had higher peak viscosity but lower stability and setback ratios compared with cocoyam. This indicates that cocoyam starch paste is better in withstanding processing conditions and would present a superior thickening characteristic than cassava starch paste. The flow properties of both starch pastes showed non-Newtonian behaviour and could be best described by the Herschel-Bulkley model. The rate index and yield stress of cocoyam starch paste was higher than that of cassava. The storage modulus of cocoyam starch paste was higher than that of cassava indicating that cocoyam starch paste was more rigid than cassava starch paste. Cassava starch paste exhibited higher paste clarity and freeze-thaw stability than cocoyam starch paste. The properties of cassava and cocoyam starches dictate their food applications.

Syneresis, the liquid separation from a food product, is one of the major challenges in the frozen food industry. It is often accelerated by unintentional temperature fluctuations, i.e. repeated freezing and thawing during distribution, transportation, storage, and consumption. It has been demonstrated that the combination of xanthan and curdlan is capable of reducing syneresis up to five freeze-thaw cycles (FTCs) with relatively stable rheological and textural properties. The present study aimed at developing an effective mixture of whey protein isolate (WPI) and xanthan-curdlan hydrogel complex (XCHC) to minimize moisture migration over multiple FTCs. The addition of XCHC to WPI solution significantly reduced the syneresis of heat-induced gels, increased the storage modulus (G') of the gels, reduced the minimum concentration of whey protein isolate required to form a gel, and minimized the discrepancies of G' in frequency sweep tests over 5 FTCs. By comparing the microstructure of mixed WPI-XCHC and pure WPI gels, it was found that XCHC served as a pore-forming agent, namely increasing the porosity, reducing the pore size, and consequently improving the gel's water retention over multiple FTCs. Results from dynamic rheological measurements showed that both G' and the gelation temperature of mixed WPI-XCHC complex were strongly pH-dependent. Moreover, the interactions between WPI and XCHC in aqueous solution were characterized. An edible coating solution containing the mixture of WPI, xanthan, and curdlan was tested on mushroom and green bell pepper. Fresh mushroom and green bell pepper samples treated with WPI-XCHC significantly prevented moisture migration after 10 days of frozen storage. The coating also decreased the changes of whiteness and greenness in mushroom and bell pepper, respectively, while significantly improved the firmness of bell peppers. Such information could provide useful guidelines when designing novel food products utilizing the unique properties provided by WPI-XCHC.

The aim of this research was to investigate the influence of modification with succinic acid/acetanhydride and azelaic acid/acetanhydride mixtures on chemical and physical properties of wheat starch. Starch was isolated from two wheat varieties and modified with mixtures of succinic acid and acetanhydride and azelaic acid and acetanhydride in 4, 6 and 8% (w/w). Total starch content, resistant starch content, degree of modification, changes in FT-IR spectra, colour, gel texture and freeze-thaw stability were determined. Results showed that resistant starch content increased by both investigated modifications, and degree of modification increased proportionally to amount of reagents used. FT-IR analysis of modified starches showed peak around 1,740 cm(-1), characteristic for carbonyl group of ester. Total colour difference caused by modifications was detectable by trained people. Adhesiveness significantly increased, while freeze-thaw stability decreased by both investigated modifications.

Oil-in-water emulsions (10% w/w n-tetradecane) were prepared at pH = 5.7 by using, as surface active agents, electrostatically formed complexes of sodium stearoyl lactylate (SSL) at a concentration of 0.4% (w/w) and chitosan (CH) in a concentration range between 0 and 0.48% w/w. The use of complexes in emulsions with a low concentration of CH (

Starch is widely used in food industry as thickener, stabilizer, fat mimetic etc. However, native starch has limitations in food industry applications such as high tendency toward retrogradation, low thermal resistance and shear resistance. Therefore, starch is often modified in different ways to change and improve its performance. In this research starch was isolated from two wheat varieties and modified with mixtures of dicarboxylic acids (succinic, glutaric, adipic, azelic acid) and acetanhydride (acid:anhydrid ratio 1:30) in 4, 6 and 8 % (d.w.b.). Thermophysical, pasting properties, as well as swelling power and solubility, paste clarity and freeze-thaw stability were determined. The results showed decrease of gelatinisation temperature and retrogradation after 7 days of storage at 4 °C after all modifications. Pasting temperature decreased as well, while maximum viscosity, swelling power and solubility increased. Paste clarity of modified starches depended on both wheat variety and type of reagent mix and freeze-thaw stability decreased after all investigated modifications.

The aim of this research was determination of influence of wheat variety and modification with epichlorohydrin on starch properties. Starch was isolated from two wheat varieties: “Golubica” and “Srpanjka” and modified with different concentrations of epichlorohydrin (0.1%, 0.3% and 0.5% v/w). Both native and modified starches were characterised. Results showed similar characteristics of native wheat starches. Modification with epichlorohydrin increased temperature of gelatinisation, but gelatinisation and retrogradation enthalpy were affected by the extent of the chemical reaction between starch and epichlorohydrin, due to differences in reactivity between wheat starch varieties. Maximum viscosity decreased as well as breakdown and setback values. Swelling power and solubility were also decreased by modification, while paste clarity and freeze–thaw stability were influenced differently, due to different extent of the chemical reaction between different starch varieties and epichlorohydrin. Colour of starch was not significantly altered by modification. Digestibility of starches can be reduced by proper selection of epichlorohydrin concentration used for modification.

Starches from cowpea and chickpea seeds were isolated and their properties were compared with those of commercial yellow pea starch. Amylose contents were 25.8%, 27.2%, and 31.2%, and the volume mean diameter of granules, determined in the dry state, were 15.5, 17.9, and 33.8 μm for cowpea, chickpea and yellow pea starches, respectively. All three legume starches showed a C-type X-ray diffraction pattern and two-stage swelling pattern. Amylopectin populations were isolated and the unit chain profiles were analyzed by HPLC after debranching with pullulanase. The degree of polymerization (DP) of short chain populations was about 6–50 and the populations of long chain had a DP of 50–80. Cowpea showed a lower weight ratio of short:long chains than chickpea and yellow pea starches. The larger portion of long side chains in cowpea amylopectin can be correlated with a higher gelatinization temperature, greater pasting peak and a slight difference in crystalline structure found for cowpea starch. Chickpea and yellow pea starches exhibited similarity in unit chain profile of amylopectin as well as in gelatinization temperature and pasting profile, while they differed in amylose content, particle size and syneresis. It is assumed that the chain length distribution of amylopectin has a large influence on starch properties.