Impact of annealing on the molecular structure and physicochemical properties of normal, waxy and high amylose bread wheat starches

Physical modification of corn and potato starches using soaking, freezing, and drying

Effects of continuous soaking, freezing, and drying on physicochemical properties of corn and potato starches were investigated to prove potentials of sequential physical modification method. High temperature soaking showed the higher swelling power than low temperature soaking in both starches right after soaking. Freezing did not significantly rearrange the molecular structure of both starches. Drying greatly change the physicochemical properties of both starches in the order of freeze, air and spray dryings. Consequently, sequential treatment of soaking, freezing, and drying lowered RVA pasting characteristics (peak viscosity, breakdown, setback) as well as amylopectin melting transition temperature compared to native starch. Particularly, potato starch showed more significant change than corn starch, possibly due to the differences in water absorption, amylose content, crystallinity, granule size, etc. Overall, high temperature soaking and freeze drying significantly change the RVA, DSC and XRD characteristics in the sequential treatment of soaking, freezing and drying of starches.

Insights into the regulation mechanisms of dual hydrothermal treatment on the structure and digestive characteristics of A- and B-type wheat starch granules

Hydrothermal treatment is a physical modification technology to alter starch structures for the production of resistant starch (RS). However, the underlying regulation mechanism of the multiscale structure and digestive properties of starch by dual hydrothermal synergistic treatment remains unclear. To solve this problem, A- and B-type wheat starch granules (AWS and BWS) were separated and subjected to toughening and heat-moisture synergistic treatment (THT) with various moisture content (10 %, 15 %, 20 %, 25 %). Scanning electron microscopy (SEM) and particle size distribution results showed that THT disrupted starch granules and the particles aggregated with each other to increase the particle size. Fourier transform infrared spectroscopy results confirmed that the hydrogen bond between starch molecules was destroyed after THT. Thermogravimetric analysis (TG) results demonstrated that the thermodynamic stability of AWS and BWS was improved after THT. Moreover, THT with 10 % or 15 % moisture content increased the crystallinity of AWS and BWS. The AWS and BWS had the highest RS content with THT at 15 % moisture content (the RS of AWS increased from 17.56 % to 25.04 % and that of BWS increased from 13.03 % to 27.08 %). These results showed that the THT with 10 % or 15 % moisture content improved the regularity of starch molecule accumulation, and promoted the crystalline structure recombination with superior crystallinity, thermodynamic stability, and high enzymatic resistance. Additionally, SEM, TG, particle size distribution, and in vitro digestion results showed that BWS was more sensitive to THT than AWS. This study provides a potential strategy to design functional wheat starchy foods with low digestibility.

Insight into characteristics in rice starch under heat- moisture treatment: Focus on the structure of amylose/amylopectin

Heat-moisture treatment (HMT) could improve the structure and physicochemical characteristics of rice starch, the structural changes of amylose and amylopectin needed to be further investigated. Hence, the starch, amylose and amylopectin were modified by HMT with different moisture contents (MC). As MC increased, starch granules became irregular, amylose appeared molten while amylopectin was less damaged. The crystal structure of starch was disrupted by HMT. The increase in the double helix structure of amylose exhibited more drastic tendency towards molecular rearrangement than amylopectin did. In addition, the reduced proportion of amylopectin A chain could affect the rearrangement of amylose. The solubility and pasting temperature improved, but the enthalpy decreased. Moderate MC (20 %, 25 %) could enhance the viscosity and dynamic viscoelasticity. HMT promoted the conversion of RDS to RS, which was significantly increased by 85.26 % at HMT-40 %. These findings contributed to a better understanding of the mechanisms by which HMT affected starch.

The evolution of granular surface structure and functional properties in rice starch during grain filling

The developmental changes in the granular surface structure and functional properties of starch during the entire grain filling period of rice (around 40 days) were investigated. The specific surface area of rice starch significantly decreased firstly then stabilized during growth due to increasing granular size. The pore volume decreased from 5.40 cm3/g at 6th day after anthesis (DAA-6) to 3.02 cm3/g (DAA-46). More starch granule-associated proteins (SGAPs) accumulated on the surface and in channels. Swelling power decreased by 46 %, whereas the flow behavior index (n) decreased by 32 % in upward curve during starch development from DAA-6 to DAA-30. Tan δ first dropped then remained steady at DAA 22-34 and lightly rebounded at the final stage, indicating that starch in the middle stage tended to have greater viscoelastic gel behavior at all sweeps. Mature starch showed lower in vitro hydrolysis rate and exhibited stronger enzymatic resistance. The results showed that granular surface features of rice starch may be an essential factor in determining rheological behavior and resistance to hydrolysis.

Influence of crystalline properties on starch functionalization from the perspective of various physical modifications: A review

The relationship between structural properties and functional characteristics of starch remains a hot subject among researchers. The crystalline property is a substantial characteristic of starch granules, undergoing different changes during modification techniques. These changes are closely related to the functional properties of modified starches. Physical modifications are eco-friendly techniques and are widely adopted for starch modifications. Therefore, understanding the impact of changes in crystalline properties during different physical modifications on starch functionality is the ultimate way to improve their industrial utilization. However, the existing literature still lacks the elucidation of changes in functional properties of starch in accordance with its crystalline properties during different physical treatments. Hence, this review summarizes the effects of the most important and widely used physical modifications on starch crystalline properties, highlighting the alterations in various functional properties such as hydration, pasting, gelatinization, and in vitro digestibility resulting from changes in crystalline characteristics in a single comprehensive discussion. Furthermore, the current review gives direction for envisaging the functionalization of starches based on deviations in the crystalline properties during several physical treatments.

Effects of moisture regulation and heat treatment synergy on structural properties and digestibility of jackfruit seed starch

To investigate the impact of moisture regulation and heat treatment synergy on the structural properties and digestibility of jackfruit seed starch (JSS), starch samples underwent heat-moisture treatment (HMT) and annealing treatment (ANN) with varying moisture content (10-30 % for HMT at 120 °C, and 50-90 % for ANN at 40 °C). The physicochemical properties and in vitro digestibility of modified-JSS were systematically investigated. Results showed that the birefringence intensity of HMT-JSS decreased at high moisture levels but remained unchanged for HMT-JSS and ANN-JSS at low moisture levels. As moisture content increased for HMT and ANN, the amylose content and relative crystallinity increased and then slightly decreased. The gelatinization temperatures increased while enthalpy and viscosity declined. At high moisture content, the infrared absorbance ratio of 1047 cm-1/1022 cm-1 decreased on HMT but increased on ANN. Resistant starch (RS) contents of both HMT-JSS and ANN-JSS were increased at appropriate moisture levels (10-15 % for HMT, 50-80 % for ANN), but decreased with excessive moisture. Besides, these changes were more pronounced on HMT than ANN. Correlation analysis showed that the RS was significantly affected by the short-range ordered structure during HMT and ANN. These results revealed that hydrothermal treatment efficiently modified the structure properties and digestibility of JSS.

Cutting-edge progress in green technologies for resistant starch type 3 and type 5 preparation: An updated review

Resistant starch (RS) is a dietary fiber that resists starch hydrolysis in the small intestine, and is fermented in the colon by microorganisms. RS not only has a broad range of benefits in the food and non-food industries but also has a significance impact on health promotion and prevention of non-communicable diseases. RS types 3 and 5 have been the focus of research from an environment-friendly perspective. RS3 is normally formed by recrystallization after physical modification, whereas RS5 is obtained by the complexation of starch and fatty acids through the thermomechanical methods. This review provides updates and approaches to RS3 and RS5 preparations that promote RS content based on green technologies. This information will be useful for future research on RS development and for identifying preparation methods for functional food.

Changes in structure, physicochemical properties and in vitro digestibility of quinoa starch during heat moisture treatment with hydrogen-infused and plasma-activated waters

In this study, comparative effect of heat moisture treatment (HMT) with distilled, hydrogen-infused and plasma-activated waters on the structure, physicochemical properties and in vitro digestibility of quinoa starch (QS) was investigated. To our knowledge, this study is the first to apply hydrogen-infused water to starch modification. The surface of HMT-modified samples was much rougher than that of native QS. HMT did not change the typical "A"-type X-ray diffraction pattern of QS but it increased its relative crystallinity. Meanwhile, amylose content, gelatinization temperature and water absorption capacity of QS significantly increased, whereas viscosity and swelling power markedly decreased. The rapidly digestible starch level of HMT-treated samples was significantly lower than that of native QS, and the resistant starch content markedly increased. These alterations were dependent on treatment moisture level. Furthermore, compared to distilled water, the HMT with hydrogen-infused and plasma-activated waters induced much more extensive effect on above properties, and the sample treated with plasma-activated water had the highest extent due to the acidic or alkaline environment and reactive oxygen and nitrogen species. These results identified that the combination of HMT with hydrogen-infused or plasma-activated water was a novel strategy to improve the thermal stability and functionality of quinoa starch.

Physicochemical characterization of wheat starch and variation of fatty acid composition in deep-fried dough sticks with different treatments

The present study investigated the effects of different deep-frying times and temperatures on the amylose content, crystal structure, thermodynamics, and other properties of deep-fried dough sticks. Results showed that the change of amylose content in deep-fried dough sticks during the deep-frying process was positively correlated with time and temperature. Moreover, the deep-frying process of deep-fried dough sticks was accompanied by the formation of starch-lipid complexes that led to the destruction of starch structure. The degreased sample and the oil sample had the same absorption peaks at 2854 and 1746 cm-1, respectively. The melting enthalpy (ΔH) of the starch-lipid complex decreased significantly. In addition, the viscosity of starch reduced as the deep-frying time and temperature increased. Furthermore, it was found that the effect of increasing deep-frying temperature was greater than that of time. PRACTICAL APPLICATION: As a popular deep-fried food, the main component of deep-fried dough sticks is starch. Starch gelatinization, protein denaturation, and interaction among components occurred during deep-frying. At present, there are few studies focusing on the properties of starch in deep-fried dough sticks in the real deep-frying system. Therefore, this study provided a theoretical basis for subsequent research by measuring the effects of different deep-frying conditions on the properties of starch in deep-fried dough sticks.

Structural and physicochemical properties of rice starch from a variety with high resistant starch and low amylose content

Research on the physicochemical properties of rice-derived endo-sperm high resistant starch (RS) with low amylose content (AC) is limited. In this study, we evaluated the physicochemical characteristics of such a starch variety and revealed that the starch granules exhibit a smoother, more refined surface with distinct edges, increased compactness, higher order of surface, and fewer cavities compared to those of a low RS rice variety. The starch crystal was classified as an A-type, which may be connected to the high amylose-lipid complex content. The branched internal long chains (B2 + B3) were abundant, allowing for easy entanglement with other molecular chains and a compact structure. Differential scanning calorimetry revealed the need for high temperature and energy to disrupt the double helix structure within the crystallization region of starch. Furthermore, starch viscosity analysis revealed a high cold paste viscosity, consistency, and setback value, with recrystallization yielding a stable structure, increased viscosity, and enhanced hydrolysis resistance to enzymes.

Effect of extrusion on the formation, structure and properties of yam starch-gallic acid complexes

This paper investigated the effects of twin-screw extrusion treatment on the formation, structure and properties of yam starch-gallic acid complexes. Yam starch and gallic acid were extruded. The microstructure, gelatinization characteristics, and rheological properties of the samples were determined. The microstructure of extruded yam starch-gallic acid complexes presented a rough granular morphology, low swelling, and high solubility. The X-ray diffraction analysis showed that the extruded yam starch-gallic acid complexes exhibited A + V-type crystalline structure. Fourier transform infrared spectroscopy results showed that the extrusion treatment could destroy the internal orderly structure of yam starch, and the addition of gallic acid could further reduce its molecular orderliness. Differential scanning calorimetry analysis showed a decrease in the enthalpy of gelatinization of the sample. Dynamic rheological analysis showed that the storage modulus and loss modulus of the extruded yam starch-gallic acid complexes were significantly reduced, exhibiting a weak gel system. The results of viscosity showed that extrusion synergistic gallic acid reduced the peak viscosity and setback value of starch. In addition, extrusion treatment had an inhibitory effect on the digestibility of yam starch, and enhanced the interaction of gallic acid with yam starch or hydrolytic enzymes. Therefore, extrusion synergistic gallic acid has improved the structure and properties of yam starch-related products, which can provide new directions and new ideas for the development of yam starch.

Pasting properties of A- and B-type wheat starch granules and annealed starches in relation to swelling and solubility

Wheat starch contains two distinct groups of granules, A-type and B-type, which have different compositions and properties. The aim of this study was to investigate the differences in pasting properties of A- and B-type wheat starch granules and their annealed starches, and to relate them to swelling properties and solubility. A- and B-type wheat starch granules were fractionated. The differences in pasting properties between A- and B-type wheat starch granules depended on starch solids content. The A-type starch had a higher pasting viscosity at ≥8 % solids content, but the trend was reversed at a lower solids content (5 %). This cross-over phenomenon in the pasting viscosity can be explained because A-type wheat starch granules have more starch molecules leached out, while swelled less at high temperatures and are probably more rigid than B-type wheat starch granules. This is the first study to show the cross-over in the pasting viscosity-starch concentration between A-type and B-type wheat starches and that B-type wheat starch has higher pasting viscosity than A-type at a low solids content. When annealed in warm water, both annealed A- and B-type wheat starch granules had higher pasting viscosities than untreated counterparts by altering the swelling of starch.

Effect of different heat-moisture treatment times on the structure, physicochemical properties and in vitro digestibility of japonica starch

Modified starch was prepared from japonica starch (JS) by heat-moisture treatments (HMT). Under the same moisture content and HMT temperature, the effects of various HMT times on the structural, properties of JS and its in vitro digestibility properties were investigated. The results showed that adhesion occurred between the particles of japonica starch after the HMT, and there were depressions on the surface. The size of the JS particles increased, the short-range ordering and relative crystallinity of the HMT-modified starch increased and gradually decreased, reaching a peak of 36.51 % at 6 h, as the HMT time was extended. The pasting indexes of HMT-modified starch decreased and then increased with the increase of the HMT time; compared with JS, the thermal stability of HMT-modified starch increased while the pasting enthalpy decreased. All the HMT-modified starches were weakly gelatinous systems and pseudoplastic fluids. Following HMT, the amount of resistant starch (RS) and slowly digested starch (SDS) grew initially before declining. The amount of RS in HMT-modified starch peaked at 24.28 % when the HMT time was 6 h. The results of this research can serve as a theoretical foundation for the creation of modified japonica starch and its use in the food industry.

Impact of Oat Supplementation on the Structure, Digestibility, and Sensory Properties of Extruded Instant Rice

The addition of oat at varying percentages (26%, 32%, 38%, 44% and 50%) was used to evaluate the structural, microstructural, and physicochemical changes in instant-extruded rice (IER). A mixture of broken rice and oat flour was extruded in a twin-screw extruder. It was found that when adding 44% oats, the gelatinization degree of the mixed powder was the lowest (89.086 ± 1.966%). The dietary fiber content increased correspondingly with the increase in oat addition. Analyses of texture properties revealed that the hardness, adhesive, and resilience values increased and then decreased with oat addition. Compared with other common instant rice (IR), the advantages of IER were evaluated in terms of microstructure, digestive performance, and flavor. IER with 44% oat addition obtained in this study had higher hardness, adhesiveness, rehydration time, and sensory score, and the content of resistant starch (RS) reached 6.06%. The electronic nose and electronic tongue analyses could distinguish the flavor of different IR efficiently. This study showed the feasibility of preparing fiber-enriched IER. The results demonstrated the potential for the development and utilization of broken rice, providing a reference for the development of IER.

Adsorption properties of corn starch modified by malt amylases and crosslinking agents: A comparison between sodium trimetaphosphate and organic acids

In order to investigate the effects of different crosslinking agents on physicochemical properties and adsorption properties of porous starch. Native corn starch was hydrolyzed by maltase and crosslinked with different crosslinking agents. Sodium trimetaphosphate crosslinked porous starch (STMP-MPS), malic acid cross-linked porous starch (MA-MPS) and citric acid cross-linked porous starch (CA-MPS) were prepared. After crosslinking, MA-MPS and CA-MPS showed a new CO stretching absorption peak at 1738 cm-1, and the crosslinking degree was much higher than that of STMP-MPS. The surface area of MA-MPS was 36 % higher than that of STMP-MPS. Compared with the average pore size of 12.43 nm of STMP-MPS, CA-MPS (14.02 nm) and MA-MPS (14.79 nm) were increased more significantly. The degradation temperature of MA-MPS and CA-MPS was increased by the introduction of ester bond, which indicates that the organic acid cross-linking strengthens the starch granules and hence more energy is required for disruption. Compared with STMP-MPS, the water absorption of MA-MPS and CA-MPS increased by 64 % and 32 %, respectively. Furthermore, the adsorption capacity of MA-MPS to essential oil was the strongest, about 4 times that of STMP-MPS. Overall, it is feasible to modify porous starch by crosslinking reaction to improve its heat resistance and adsorption properties.

Modification of Starches and Flours by Acetylation and Its Dual Modifications: A Review of Impact on Physicochemical Properties and Their Applications

Various modification treatments have been carried out to improve the physicochemical and functional properties of various types of starch and flour. Modification by acetylation has been widely used to improve the quality and stability of starch. This review describes the effects of acetylation modification and its dual modifications on the physicochemical properties of starch/flour and their applications. Acetylation can increase swelling power, swelling volume, water/oil absorption capacity, and retrogradation stability. The dual modification of acetylation with cross-linking or hydrothermal treatment can improve the thermal stability of starch/flour. However, the results of the modifications may vary depending on the type of starch, reagents, and processing methods. Acetylated starch can be used as an encapsulant for nanoparticles, biofilms, adhesives, fat replacers, and other products with better paste stability and clarity. A comparison of various characteristics of acetylated starches and their dual modifications is expected to be a reference for developing and applying acetylated starches/flours in various fields and products.

Microstructural, physicochemical properties and starch digestibility of brown rice flour treated with extrusion and heat moisture

Effects of heat moisture treatment (HMT), extrusion treatment (ET), and the combination treatment (HMT-ET) on microstructural, physicochemical properties, and starch digestibility of brown rice flour (BRF) were investigated. With a rise in resistant starch (RS), melting temperature, and a decrease in swelling capacity (SC), peak viscosity, and apparent amylose content (AAC), the HMT-ET BRF showed a significant lower expected glycemic index (eGI) than HMT and ET. XRD and FTIR results showed ET, HMT-ET caused the transition of starch crystals from amorphous to crystalline region, suggesting the formation of the starch-lipid complex. The analysis of DSC and RVA proved HMT-ET flours induced starch gelatinization and inhibited the starch retrogradation of BRF compared with the other three flours. Correlation analysis suggested that the combined effect of HMT and ET was response for the changes in physicochemical properties and reduction of in vitro starch digestibility. Overall, the BRF after HMT-ET with improved physicochemical properties and starch digestibility could be better utilized as a good substitute for carbohydrate sources.

High-protein rice flour in the development of gluten-free pasta

Cahokia Rice, a new biofortified high-protein (10%-12%) variety of rice, was used to develop and analyze a gluten-free pasta. Different pastas were made with high-protein white rice flour (HPWRP), high-protein brown rice flour (HPBRP), commercial white rice flour (CWRP), commercial brown rice flour (CBRP), and wheat flour (WP). Cooking quality of the pasta was evaluated by measuring pasting properties, cooking time, water absorption capacity, and cooking loss. Proximate analysis, color, and texture were done on dry and cooked pasta. Sensory testing was done to determine consumer acceptability and purchase intent of HPWRP and HPBRP in comparison to WP. HPWRP and HPBRP had higher pasting temperatures and lower peak viscosity than commercial rice flour pastas, which was related to the higher protein content. HPWRP and HPBRP had less cooking loss than CWRP and CBRP; all treatments had similar water absorption capacity (∼130%) except for WP that was higher (140%). White rice pastas along with WP took more time to cook than brown rice pastas. HPWRP and HPBRP had higher protein (around 7.5%) and fat content, creating a firmer cooked pasta (138.23 g HPBRP, 179.82 g HPWRP) than commercial rice pastas. Consumers' overall liking of HPBRP (5.37), HPWRP (6.00), and WP (6.81) was acceptable. Color, firmness, and stickiness attributes negatively affected the overall liking of HPWRP and HPBRP. Cooked high-protein rice flour pastas had improved firmness and cooking loss closer to wheat resulting in an acceptable product in overall liking. It is recommended to further improve the color, firmness, and stickiness of the pasta to reach higher sensory acceptability. PRACTICAL APPLICATION: This research provides a possible use for a new high-protein rice flour that can be used in gluten-free products. This will help the rice industry by adding value to the product. Those persons who are Celiac or who desire more nutritional gluten-free products will have a healthier gluten-free pasta option.

Physicochemical, structural, and rheological characteristics of corn starch after thermal-ultrasound processing

Thermal-ultrasound treatment is a green technology that can significantly alter the structural and functional properties of starches. This research extend the effect of at different temperatures (25 °C, 45 °C, and 65 °C) and times (30 and 60 min) on the physicochemical, structural, and rheological properties of corn starch was studied. Amylose content, solubility, swelling power, and the least gelling content increased with increasing temperature and time. Starch treated at 45 °C for 30 min had the lowest syneresis among all treatments. Thermal-ultrasound treatment at 25 °C and 65 °C for 60 min caused increasing paste clarity. Microscopic observations demonstrated that the starch granules were agglomerated at 65 °C. Although the crystallinity of samples decreased from 35.42% to 8.94%, the storage modulus was more than the loss modulus during the frequency sweep test. Pasting properties showed that pasting temperatures shifted to higher values after treatment. Nonetheless, the maximum viscosity decreased, and the final viscosity of the treated samples demonstrated that short-term retrogradation could deteriorate. Results showed that thermal-ultrasound is a viable technique for starch modification compared to conventional thermal and ultrasound treatments.

A study on the structural, physicochemical, rheological and thermal properties of high hydrostatic pressurized pearl millet starch

Starch in native form has limited application due to functional and physicochemical characteristics. To overcome these limitations, starch can be modified by non-thermal technologies such as high hydrostatic pressure (HHP). This study investigates high-pressure-induced gelatinization and the effect of this process on the structural, functional, morphological, pasting, thermal, physical and rheological properties of millet starch. The suspension of millet starch and water was pressurized at 200, 400 and 600 MPa for 10, 20 and 30 min to modify the starch in terms of structure, morphology, some physicochemical and rheological properties. Swelling strength and starch solubility decreased as a result of treatment with HHP. All treatments caused to increase in water holding capacity of the starch (from 0.66 % for native starch to 2.19 % for 600 MPa-30 min). Thermal analysis showed a decrease in gelatinization temperature and enthalpy of gelatinization and the pasting properties showed a decrease in the peak viscosity after HHP treatment. In addition, HHP treatment caused to increase in the hydration ability of starch by creating porosity and gaps in the granule surface and increasing the specific surface area. HHP application resulted in an increase in the peak time and pasting temperature and a decrease in breakdown and peak viscosities, final viscosity and setback viscosity in comparison with native starch of millet. The starch sample treated with 600 MPa for 30 min had the lowest syneresis and retrogradation ability. Increasing pressure and the time led to an increase in the elastic nature of the starch samples. According to the results, it is possible to increase usage area of starches in the food industry by improving its technological with HHP. This green physical technology can influence the quality parameters of starch, which can provide benefits for product machining and economic purposes.

Pressure moisture treatment and hydro-thermal treatment of starch

Starch is often subjected to denaturation treatment to improve its useful properties and eliminate its shortcomings. Various methods have been developed to produce modified starches with different properties and for a variety of uses. Because physically modified starch can be produced without chemical substances or biological agents, the modification method is very simple and inexpensive, and the resulting material can be used as clean label starch. Among these physical modification technologies, heat moisture treatment (HMT) is a universally valid technology, but little is known about pressure moisture treatment (PMT)-related technology. Physical modification of starch using PMT results in new functions and value-added characteristics required by industry, and PMT has the potential to produce starch with new functions. In this paper, PMT-related technologies for physically modified starch, the difference between PMT and the hydro-thermal treatment, and clean label starch manufacturing using HMT and PMT were investigated.

Effects of different modified starches and gums on the physicochemical, functional, and microstructural properties of tapioca pearls

The effects of different modified starch and gums on the physicochemical, functional, and microstructural properties of tapioca pearls were investigated. The addition of starch acetate (SA) and carboxymethylcellulose (CMC) improved the springiness, hardness, cooking properties, and overall acceptability of pearls. Samples added with CMC presented higher peak viscosities, breakdown viscosities, onset gelatinization temperature, and lower enthalpy of gelatinization values compared to control pearls. Furthermore, Rheology and LF-NMR results indicated that all five kinds of modifiers promoted the formation of tighter network structures in products. SEM showed that the addition of SA and hydroxypropyl distarch phosphate (HDP) could fill the voids in the internal gel network of the pearls, thus promoting the formation of a continuous phase network. This study proved SA, HDP, and CMC as modifiers could have tremendous potential to improve the quality of pearls before and after cooking.

Understanding the Structure, Thermal, Pasting, and Rheological Properties of Potato and Pea Starches Affected by Annealing Using Plasma-Activated Water

In this research, annealing (ANN) using plasma-activated water (PAW) was first employed to modify potato and pea starches. Compared with the conventional ANN using distilled water (DW), the granular morphology of two starches was not significantly affected by PAW-ANN. The results of X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy showed that PAW-ANN could reduce the long and short-range ordered structure of potato starch while improving the long and short-range ordered structure of pea starch. Differential scanning calorimetry (DSC) analysis indicated that PAW-ANN lowered the gelatinization enthalpy of potato starch and increased the gelatinization enthalpy of pea starch. The analysis of viscosity and dynamic rheological characteristics illustrated that PAW-ANN reduced the peak viscosity and improved the gel strength of starch pastes. PAW-ANN represents a novel modification method for modifying the structure, reducing the viscosity, improving the gel strength of starch, and is very promising for applying in starch-based hydrogels and food additives.

Effect of selected physical and chemical modifications on physicochemical, pasting, and morphological properties of underutilized starch from rice bean (Vigna umbellata)

Starch was extracted from the rice bean which is largely underutilized and modified by physical (i.e. heat moisture treatment and retrogradation) and chemical (i.e. esterification and acid alcohol modification) methods. Both, physical and chemical modifications significantly (p < 0.05) affected the physicochemical, pasting, particle size and morphological properties of rice bean starch. Both amylose content and swelling power reduced after physical and chemical modifications. Among modified starches, retrograded starch showed higher solubility (8.56%) at 90 °C. Retrogradation also resulted in higher values of water (251%) and oil absorption (106%) capacities in comparison to other modified starches. Physical modifications greatly influenced the pasting properties in comparison to chemical modifications. The particle size distribution followed the order: native starch (659.8 nm) > heat moisture treated (434.3 nm) > retrograded (355.4 nm) > esterified (218 nm) > acid alcohol treated starch (234.5 nm). The study revealed that the particle size of rice bean starch was reduced by both physical and chemical modifications. FE-Scanning electron microscopy was used to study the morphological characteristics of starches and it was observed that retrogradation had a pronounced effect on the starch granules morphology.

Removal of starch granule associated proteins alters the physicochemical properties of annealed rice starches

The effect of removal of starch granule associated proteins (SGAPs), annealing and dual-treatment on physicochemical properties of three rice starches with different amylose content (AC) was investigated. SGAPs removal reduced stability of starch granules, thus increasing amylose leaching, swelling power, solubility, and pseudoplasticity of Qiuguang (15.6% AC) and Luhui (22.1% AC) rice starches, decreasing pseudoplasticity of Yangfunuo (1.56% AC) starch, and decreasing T_o, T_p, and T_c, pasting viscosity and storage modulus of all three rice starches. Annealing decreased amylose leaching of the three starches, and pasting properties, pseudoplastic and storage modulus of Yangfunuo starch, but increased swelling power of the three starches, ΔH and T_o of Qiuguang starch, and pasting properties and pseudoplasticity of Qiuguang and Luhui starches. The effect of dual-treatment was generally the sum of effect of SGAPs removal and annealing treatment. But an interaction effect of the dual-treatment was observed for some parameters. The effect of annealing was closely related to the variety and composition of the starch.

Physicochemical properties and in vitro digestibility of hydrothermal treated Chinese yam (Dioscorea opposita Thunb.) starch and flour

The objective of this study was to investigate the effects of hydrothermal treatments (heat-moisture treatment (HMT) and annealing (ANN)) on the physicochemical properties and in vitro digestibility of yam starch and yam flour. Hydrothermal treatments decreased the pasting properties of yam starch and yam flour. Compared with yam starch, HMT significantly (p < 0.05) reduced the pasting viscosities of yam flour. Both HMT and ANN caused an increase of the gelatinization temperatures (T_o, T_p, and T_c) and a decrease of enthalpy (△H). The increasement in ratio of 1047/1022 cm^-1 and 995/1022 cm^-1 suggested that HMT and ANN resulted in an increase in short-range order. The crystalline pattern of all samples was still A-type, and HMT yam starch exhibited higher crystallinity (26.20%). The most significant inhibition of in vitro digestibility was found in HMT yam flour, with slowly digestible starch and resistant starch contents increasing by 3.73% and 4.40%, respectively. Hydrothermal treatments made the no-starch ingredients in yam flour agglomerate and adhere to starch granules. Confocal laser scanning microscopy showed that the starch being coated or embedded by protein was a possible reason for the differences in physicochemical properties and in vitro digestibility between yam starch and yam flour.

Effects of heat-moisture treatment on the thermal, functional properties and composition of cereal, legume and tuber starches-a review

Several methods are currently employed in the modification of starch obtained from different botanical sources. Starch in its native form is limited in application due to retrogradation, syneresis, inability to withstand shear stress as well as its unstable nature at varying temperatures and pH environment. Modification of starch is therefore needed to enhance its food and industrial application. A primary and safe means of modifying starch for food and industrial use is through hydrothermal methods which involves heat-moisture treatment and annealing. Heat-moisture treatment (HMT) is a physical modification technique that improves the functional and physicochemical properties of starch without changing its molecular composition. Upon modification through HMT, starches from cereals, legumes and tuber crops serve as important ingredients in diverse food, pharmaceutical and industrial processes. Although changes in starch initiated by HMT have been studied in starches of different plant origin, this work further provides insight on the composition, thermal and functional properties of heat-moisture treated starch obtained from cereals, legumes and tuber crops.