Gelatinization Enthalpy Research Articles

Impact of Cooking Methods on Phenolic Acid Composition, Antioxidant Activity, and Starch Digestibility of Chinese Triticale Porridges: A Comparative Study between Atmospheric Pressure and High Pressure Boiling.

Water boiling under atmospheric pressure (CAP) and water boiling under high pressure (CHP) are two popular domestic cooking methods for Chinese porridge making. In this study, we aimed to evaluate the effects of these two methods on the phenolic acid composition, antioxidant activity, and starch digestibility of triticale porridges. The contents of total free and total bound phenolic acids in the CHP sample were 1.3 and 1.6 times higher than those in the CAP counterpart, respectively, although the DPPH and ABTS values of these two samples were comparable. CAP induced more small pieces of starch than CHP, and the gelatinization enthalpy was 19% higher in the CHP sample than that in the CAP. Both cooking methods increased the starch digestibility, while the CHP sample (58.84) showed a lower GI than the CAP (61.52). These results may promote the application of triticale in health-promoting staple foods.

Thermal Properties and Dynamic Rheological Characterization of Dioscorea Starch Gels.

Yam (Dioscorea. sp.) is an edible starchy tuber with potential for being a commercial source of starch for industrial purposes, but yam starch is underutilized. The dynamic oscillatory and thermal properties of yam starches from sixteen varieties each of Dioscorea. rotundata, Dioscora. alata, Dioscorea. bulbifera and one variety of Dioscorea. dumetorum from Nigeria were studied to determine their potential for industrial utilization. The storage modulus, loss modulus, damping factor and complex viscosity as a function of frequency (ω) of the dioscorea gels, as well as the onset temperature (To), peak gelatinization temperature (Tp), end of gelatinization (TC), and gelatinization enthalpy of the starches were determined by standard procedures. Results showed that all the dioscorea starches showed a typical elastic behavior with the magnitude of G' greater than G″ while tan δ < 1 in all varieties. Thus, the starch gels were more elastic than viscous. All the starch gels exhibited shear thinning characteristics and showed frequency (ω) independence characteristics of weak gels. D. rotundata varieties had the lowest ∆Hgel, while D. bulbifera varieties had the highest. The diversity of the visco-elastic and thermal properties of the yam starch gels from different varieties and species can be an advantage in their utilization in both food and non-food industries.

Impact of lipids on the functional, rheological, pasting and thermal properties of ultrasound-processed canary seed flours

Canary seed, a gluten-free cereal, is renowned for its high content of fats, starch, and proteins. The extraction of oil is often necessary to extend flour shelf life or obtain purified starch and protein fractions. Similar to many gluten-free flours, it may require additional thermal treatments to enhance its suitability to formulate several food products. Thus, this study investigated the impact of ultrasound (US) treatment on the techno-functional and physicochemical properties of both whole (WCS) and defatted (DWCS) canary seed flours. The US treatment slightly increased water and oil absorption capacities in WCS. Lipids in the flour and treatment temperature affected the surfactant properties. Untreated and treated defatted DWCS flours exhibited higher emulsifying activity (up to +36%) and foaming capacity (up to +340%) than WCS. The presence of lipids and US treatment influenced protein extraction, with changes in albumins (WCS and DWCS), globulins (DWCS) and prolamins (WCS) recovery. US treatment altered pasting and rheological properties of all studied flours, impacting viscosity and starch-lipid complex formation. Rheological properties were lipid-dependent, and defatted samples formed stronger gels. US treatment decreased gelatinization enthalpy in WCS (up to −9.5%) and increased it in DWCS (up to +11.3%) flours. Moreover, lipids significantly influenced retrogradation, which was absent in untreated and treated WCS flours. US-treated flours displayed similar diffraction patterns to untreated samples, but with reduced intensities as temperature increased. The untreated defatted sample exhibited a 9% lower crystallinity. These findings highlight the benefits of US treatment and defatting for improving gluten-free food products formulated with canary seed flour.

Effects of Waterlogging at Flowering Stage on the Grain Yield and Starch Quality of Waxy Maize.

Waterlogging is a common abiotic stress in global maize production. Maize flowering stage (from tasseling to silking) is more fragile to environmental stresses, and this stage frequently overlapped the plum rain season in the middle and lower reaches of Yangtze river in China and affect the yield and quality of spring-sown maize severely. In the present study, the soil moisture content under control and waterlogging conditions at the flowering stage was controlled by a negative-pressure water supply and controlling pot device in a pot trial in 2014-2015. The grain yield, starch content, and starch structural and functional properties under two soil moisture levels were compared using Suyunuo5 (SYN5) and Yunuo7 (YN7) as materials, which are the control hybrids of National waxy maize hybrid regional trials in Southern China. The results observed that the grain yield was reduced by 29.1% for SYN5 with waterlogging due to the decreased grain weight and numbers, which was significantly higher than that of YN7 (14.7%), indicated that YN7 was more tolerant to waterlogging. The grain starch content in YN7 was decreased by 9.4% when plants suffered waterlogging at the flowering stage, whereas the content in SYN5 was only decreased in 2014 and unaffected in 2015. The size of starch granules and proportion of small-molecule amylopectin with waterlogging at the flowering stage increased in SYN5 and decreased in YN7 in both years. The type of starch crystalline structure was not changed by waterlogging, whereas the relative crystallinity was reduced in SYN5 and increased in YN7. The pasting viscosities were decreased, and the pasting temperature was unaffected by waterlogging in general. The gelatinization enthalpy was unaffected by waterlogging in both hybrids in both years, whereas the retrogradation enthalpy and percentage in both hybrids were reduced by waterlogging in 2014 and unaffected in 2015. Between the two hybrids, YN7 has high pasting viscosities and low retrogradation percentage than SYN5, indicated its advantages on produce starch for more viscous and less retrograde food. In conclusion, waterlogging at the flowering stage reduced the grain yield, restricted starch accumulation, and deteriorated the pasting viscosity of waxy maize. Results provide information for utilization of waxy maize grain in food production.

Changes in Intergranular Air Properties and Chemical Parameters of Short-term Stored Bulk Shelled Corn with Slightly High Moisture Content

Objective: This study is to determine the main parameters influencing the storage of shelled corn with slightly high moisture content (MC) so that its quality can be maintained. Methods: The intergranular air properties and chemical changes was determined in 4,169 tonnes of shelled corn bulk with an average MC of 15.3% and a height of 5m, which was stored for 90 days in a large warehouse in Shandong Province, China, from winter to early spring. The intergranular air property parameters were calculated with self-compiled software. Results: Fans were used to achieve temperature-equalizing aeration at a low rate (5.87m3/h/t) after warehousing, which decreased the bulk temperature from 6.8 to 4.7℃. Afterwards, with the increase in ambient temperature, the surface-layer grain temperature increased drastically, while that of the bottom layer increased slowly and those of the middle layers increased even more slowly. The minimum and mean cumulative dry-bulb, wet-bulb and dew-point temperatures (DPT) increased in the order of middle layer˂ bottom layer˂ surface layer. Free fatty acid content, kernel breakage percentage, water adsorption rate, gelatinization enthalpy, peak enthalpy, and fatty acid profiles (C16:0, C18:0, C18:3n3, C20:0 and C20:1) were significantly related to the cumulative intergranular air properties of grain bulk. Conclusion: The above physio-chemical parameters were significantly influenced by the minimum and mean cumulative values of relative humidity, Humidity ratio and DPT in the bulk, and can be used to evaluate the quality of shelled corn with slightly high MC during short-term storage.

Appearance, components, pasting, and thermal characteristics of chalky grains of rice varieties with varying protein content

This study investigated two rice varieties, GuichaoII and Jiazao311, with distinct protein content to determine the variation in appearance, components, pasting, and thermal properties of rice with different chalkiness degrees. Grain length, width, head rice weight, and whiteness of both varieties markedly increased as chalkiness increased from 0% to 50%. However, the variation in components, pasting, and thermal characteristics of chalky grain substantially differed between the rice varieties. The protein content of GuichaoII (low protein content) significantly increased with the chalkiness degree, along with a significant increase in onset, peak, and conclusion temperatures and gelatinization enthalpy. In Jiazao311 (high protein content), the chalkiness degree increased with the protein content but decreased with the starch content, along with increased trough, final, setback, and consistency viscosities. Compared to amylose content, protein content had a greater influence on the thermal properties and pasting characteristics of chalky grains of GuichaoII and Jiazao311, respectively.

Investigation of ultrasound-assisted starch acetylation by single- and dual- frequency ultrasound based on rheology modelling, non-isothermal reaction kinetics, and flow/acoustic simulation

To achieve wheat starch acetylation (AC) with a high degree of substitution (DS), the acetylation process was carried out using various ultrasonication frequencies, including 25 kHz, 40 kHz, and 25 + 40 kHz. In the second step, wheat starch's ultrasound-assisted acetylation (UAA) is simulated using various approaches including the rheology models, non-isothermal reaction kinetics, and flow/acoustic modelling. The computational fluid dynamics (CFD) simulation solves the non-linear acoustic governing equation to determine the flow field and the amount of delivered ultrasound energy. The acetylated starch increased peak and final viscosity, with the highest values observed for the 25 + 40 kHz frequency than other single frequencies (25 kHz and 40 kHz). The viscosity of the starch is specified based on the experimental data using Herschel–Bulkley, power law, and Casson rheology models. According to differential scanning calorimetry (DSC) analysis, the gelatinization parameters and enthalpy of gelatinization (ΔHgel), were found to be lower in acetylated starches at the frequency of 25 + 40 kHz compared to those at frequencies of 25 kHz and 40 kHz, as well as native starches (NS). Moreover, the gelatinization process is examined by implementing the non-isothermal reaction kinetics to obtain the activation energy and reaction order. Based on the results obtained, implementing sonication at 25 kHz reduces the activation energy by 70.3 % compared to native starch. However, the same parameter is obtained to be 69.9 % and 67.1 % for the application of 40 and 25 + 40 kHz transducers, respectively. Additionally, during the sonication treatment, the yield shear stress increases between 24.1 and 31.8 %, based on the applied frequency. Morphology analysis determined by scanning electron microscopy (SEM) revealed that the surfaces and small granules underwent more damage in acetylated starches at frequencies of 25 kHz and 40 kHz. However, in acetylated starches at 25 + 40 kHz, the larger granules were more affected than the smaller ones.

Effect of different screw speeds on the structure and properties of starch straws

To illustrate the action mechanism of screw speed on the performance of starch-based straws during the extrusion process, starch-based straws at different screw speeds were prepared using a twin-screw extruder and the structures and characteristics were compared. The results indicated that as screw speeds improved from 3 Hz to 13 Hz, the A chain of amylopectin increased from 25.47 % to 28.87 %, and the B3 chain decreased from 6.34 % to 3.47 %. The absorption peak of hydroxyl group shifted from 3296 cm−1 to 3280 cm−1. The relative crystallinity reduced from 13.49 % to 9.89 % and the gelatinization enthalpy decreased from 3.5 J/g to 0.2 J/g. The performance of starch straws did not increase linearly with increasing screw speeds. The starch straw produced at screw speed of 7 Hz had the largest amylose content, the highest gelatinization temperature, the minimum bending strength, and the lowest water absorption rate in hot water (80 °C). Screw speed had a remarkable impact on the mechanical strength, toughness and hydrophobicity of starch-based straws. This study revealed the mechanism of screw speed on the mechanical strength and water resistance of starch straws in the thermoplastic extrusion process and created the theoretical basis for the industrial production of starch-based straws.

Effect of “shape” on technological properties and nutritional quality of chickpea-corn-rice gluten free pasta

Macroscopic and microscopic food structural characteristics play an important role in product's technological properties and nutritional attributes. The effects of macroscopic (pasta shape, PS) and microscopic (flour particles, FP) structural attributes were independently investigated in gluten-free (GF) chickpea-corn-rice short pasta (50% chickpea) considering cooking quality, physicochemical attributes, thermal properties, in vitro digestibility of starch (IVSD) and protein (IVPD). Different PS (rigatoni, fusilli, fusilli piccolo, caserecce, gnocchetti sardi) and different chickpea FP (conventional, precooked, fine, coarse) were considered. With regards to PS effect, rigatoni-shaped pasta differed significantly from other PS having the longest cooking time, a harder and less adhesive texture, the highest gelatinization enthalpy, the lowest IVPD, and higher resistant starch content. The chickpea FP modulated the flour pasting properties and slightly impacted both pasta cooking quality and nutritional characteristics regarding IVSD and IVPD. This work suggested that pasta structural attributes, especially PS, can modify pasta cooking quality, physicochemical, and nutritional characteristics and should, therefore, be considered in rational product design to provide food products with desired properties.

Mechanism of interaction between agar and corn starch: Towards improved properties of starch-based cryogel

In this study, agar/corn starch cryogels with different morphologies and characteristics were synthesized using sol, gel, and freeze-drying techniques. The addition of agar increased the gelatinization temperature of starch and decreased the gelatinization enthalpy, thereby inhibited the gelatinization process of starch. The rheological data revealed that the addition of agar accelerated the gelatinization process of the agar/starch binary system and significantly increased the storage modulus of the hydrogel. Fourier transform infrared spectroscopy, X-ray diffraction analysis, and scanning electron microscopy demonstrated that agar disrupted the retrogradation and crystal structure of starch. A lower concentration of agar destroyed the network structure formed by starch and increased the pore size of cryogel. However, the fiber-bundle structure formed in the large pores after increasing the agar content made the cryogel network more compact. However, this led to marginal increase in cryogel density which endowed the cryogel with significantly improved compressive strength (5.01 MPa) and toughness. Therefore, the incorporation of agar into starch to prepare a composite cryogel is an effective approach for improving the properties of starch-based cryogels.

Evaluation of dual modification by high hydrostatic pressure and annealing on the physicochemical properties of bean starch

This study investigated the physical modifications by high hydrostatic pressure (HHP) at 600 MPa for 30 min/30 °C, annealing (AN) at 50 °C/24 h and the combination of both (HHP + AN and AN + HHP) applied to yellow bean starch to verify changes in morphology, X-ray diffraction, molecular order, thermal properties and pasting properties of native (NS) and modified starches. Morphological analysis showed loss of sphericity and increase in diameter with the appearance of pores on the surface after application of treatments. The AN starch showed lower values of syneresis, degree of double helix (DD), order (DO), and viscosity of the paste obtained by RVA. It exhibited a Vh-type classification with the appearance of the amylose–lipid complex. However, the gelatinization temperatures, as well as the enthalpy of gelatinization, were significantly higher. On the other hand, the starch treated with HHP showed a higher Setback (SB) value. The greatest modifications were found for the starches subjected to the combined treatments (AN + HHP) and (HHP + AN), where the order of the treatments was significant for the morpho-structural changes of yellow bean starch. According to the micrographs, the surface aspect was altered, with AN + HHP showing greater irregularities and flat yet irregular faces, as well as a larger granule diameter (147.05). The X-ray diffractogram showed a reduction in crystallinity from 28.14 % (NS) to 18.09 % (AN + HHP) and classified the starch as type “A”. The double modification (HHP + AN and AN + HHP) reduced the gelatinization temperature and the enthalpy of gelatinization but had no effect on the bands of the FT-IR spectrum. There was only a reduction in the degree of order and the double helix. Finally, the treatment with AN + HHP is more effective as the gelatinization with AN facilitates the application of HHP. Both methods used are classified as physical (thermal and non-thermal), aiming to minimize environmental impacts and achieve faster and safer morpho-structural modification without leaving chemical residues in the products.

Mung Bean Starch and Mung Bean Starch Sheet Jelly: NaCl-Based Characteristics Variation.

Empirical evidence indicates that NaCl can improve the quality of mung bean starch sheet jelly (MBSS) when properly incorporated. In this study, by comparison with a sample without NaCl, the influences of NaCl (1.5-8%, w/w) on the physicochemical and structural properties of mung bean starch (MBS) and the quality of MBSS were investigated. MBS with added NaCl had greater gelatinization temperature and pasting parameters but lower gelatinization enthalpy than native MBS. With the addition of NaCl, the drying rate of MBSS first accelerated and then declined in the oven-drying process. The addition of NaCl improved the cooking properties of MBSS but decreased the hardness of cooked MBSS. Rheological results implied that the linear viscoelastic region of cooked MBSS decreased with the NaCl addition, and the storage modulus and tan δ were more frequency-dependent than the loss modulus of cooked MBSS. The addition of NaCl gradually increased the toughness of dried MBSS and the overall acceptability of cooked MBSS. Furthermore, NaCl decreased the structure order degree of starch in MBSS. Correlation analysis demonstrated that the quality of MBSS had a significant correlation with the molecular and lamellar order of starch. Overall, NaCl could improve the quality of MBSS by regulating the thermal, gelatinizing, and structural properties of MBS.

Investigating the effect of natural fermentation in modifying the physico-functional, structural and thermal characteristics of pearl and finger millet starch.

In recent years, millets are often considered an emerging crop for sustainable agriculture. Therefore, millets can be exploited as an alternative source of starch which has many applications ranging from food, packaging, bioplastics, and others. However, starch is seldom used in its native form and is more often modified to enhance its functional properties. In literature, many traditional millet-based food recipes often incorporate a fermentation step before cooking. Therefore, using this traditional knowledge fermentation has been explored as a potential method for modifying millet starch. Pearl millet (PM) and finger millet (FM) flour were allowed to naturally ferment for 24 h followed by starch extraction. Compared to native (N) starch,water/oil holding capacity and least gelation concentration of fermented (F) starch decreased with no significant change in swelling power. The solubility, paste clarity and in vitro digestibility of starch were significantly affected by fermentation. X-ray diffraction (XRD) data indicates that after fermentation, crystallinity increased while the A-type crystalline structure remained intact. Fourier-transform infrared (FTIR) spectra showed no deletion or addition of any new functional groups. Thermal characterization by differential scanning calorimetry (DSC) showed that the enthalpy of gelatinization of PM starch decreased while that of FM starch increased after fermentation. The results indicate that 24 h natural fermentation had a significant impact on functional properties of starch without altering the structural architecture of starch granules. Therefore, fermentation can be further explored as a low-cost alternative for starch modification. © 2023 Society of Chemical Industry.

Synergistic modification of ultrasound and bamboo leaf flavonoid on the rheological properties, multi-scale structure, and in vitro digestibility of pea starch.

In this study, the effect of ultrasonic treatment (UT), bamboo leaf flavonoid (BLF), ultrasonic treatment prior to bamboo leaf flavonoid (UT-BLF), and bamboo leaf flavonoid prior to the ultrasonic treatment (BLF-UT) on the rheological properties, multi-scale structure, and digestibility of pea starch (PS) were investigated. The morphology and crystal structure of starch granules were destroyed by UT, thereby promoting starch retrogradation and digestion. The binding between BLF and starch through hydrophobic interactions and hydrogen bonds inhibited the interaction between starch molecular chains and impaired their double helix structure, thus effectively retarding starch retrogradation. The anti-digestibility of starch was enhanced after synergistic treatment. Compared with single treatment, synergistic treatment increased the ordered structure and gelatinization enthalpy of starch. In comparison with the UT-BLF group, the viscoelastic and thermal stability of BLF-UT group were improved with the increase in ordered structure. This study could provide valuable information for PS modification.

Effects of suspension media on high pressure processing of starches with different crystalline structures.

High pressure processing (HPP) is a starch modification method generally conducted in water, and little is known about the pressure-induced changes in different media. This study investigated the effects of water versus sodium sulfate on corn, potato, and pea starches subjected to HPP at 690MPa. HPP in both media reduced gelatinization enthalpy and crystallinity for all starches. HPP in sodium sulfate promoted the transition of common corn and potato starches to C-type crystallites. HPP starches in sodium sulfate generally displayed lower pasting temperatures, higher peak viscosities, and greater breakdowns than in water. Alpha-amylase susceptibility increased for all HPP starches and was generally lower in sodium sulfate than in water. HPP common corn and potato starchs in sodium sulfate displayed a porous structure after α-amylase digestion. The competition of sodium sulfate for water molecules between starch helices induced variations in the properties of HPP starches with different crystalline structures.

Humidity-controlled heat treatment of fresh spinach noodles for color preservation and storage quality improvement

The high sensitivity to color browning during room-temperature storage was a significant factor in limiting the development of fresh spinach noodles (FSN). The practice of humidity-controlled heat treatment (HCHT) at varying temperatures, relative humidity, and time was carried out to limit enzyme activity and improve the quality of FSN. Results showed that HCHT could maximize the color preservation of fresh spinach noodle quality while effectively inactivating polyphenol oxidase and the yeasts, and mold count in FSN during storage was almost undetectable after mild conditions (80 °C). The hardness and chewiness of HCHT noodles were significantly increased, but the free sulfhydryl content was reduced. At 80 °C, 90 %, 5 min, protein structural aggregation was found in the microstructure of HCHT fresh spinach noodles. HCHT also caused partial gelatinization, as evidenced by the decrease in starch gelatinization enthalpy from 5.49 to 4.77 J/g, although the gelatinization degree of FSN was comparatively low.

Elevated Ripening Temperature Mitigates the Eating Quality Deterioration of Rice in the Lower Grain Position Due to the Improvement of Starch Fine Structure and Properties

Elevated ripening temperature (ET) impacts rice grain quality. In this study, two rice varieties were investigated to evaluate the characterization of starch fine structure and grain eating quality under ET conditions. Rice exposure to ET increased the proportion of large-sized granules and starch granule average size, regardless of grain position. Compared to normal temperature (NT), the amylose content (AM) in the upper grain position (UP) exhibited a significant increase under ET, whereas the contrary results showed a decrease in the lower grain position (LP), and the proportion of shorter amylopectin chains increased under ET in UP or LP, whereas the proportion of long amylopectin chains decreased, resulting in a higher starch gelatinization temperature and enthalpy under ET. For grain position, compared to LP, UP had higher AM and a higher proportion of long amylopectin chains, leading to higher gelatinization enthalpy under ET. For eating quality, we found that ET deteriorated the eating quality of rice compared to NT, and UP had higher eating quality than LP under NT; however, there was a comparable eating quality between UP and LP under ET. Hence, elevated grain filling temperature mitigated the eating quality deterioration of rice grain in LP due to the lower AM and gelatinization enthalpy and the higher proportion of shorter amylopectin chains.

PHYSICOCHEMICAL AND FUNCTIONAL PROPERTIES OF RS3 OBTAINED FROM CILACAP BREADFRUIT (Artocarpus altilis (Parkinson) Fosberg) STARCH

Cilacap breadfruit is a variety native to Indonesia, characterized by superior properties, including fast growth, large fruit size, high carbohydrate, and starch content. This plant has a relatively high content of amylose and resistant starch (RS), allowing its conversion into RS for health benefits. Therefore, this study aimed to investigate the effect of autoclaving temperature (100, 121, and 140℃), cooling at 4ºC, and storing time (24 and 48 hours) on the formation of RS from Cilacap breadfruit, and determine its physicochemical (amylose, amylopectin, resistant starch, pasting properties, and thermal properties), as well as functional properties. The results showed that autoclaving-cooling increased the amylose and RS content, water solubility, onset, and peak of thermal temperature. The pasting properties of all parameters, gelatinization enthalpy, swelling power, and amylopectin content were decreased. Amylose content also significantly increased (p≤0.05) from 31.01±0.24 to 37.91±0.43, and RS content (p≤0.05) from 10.98±0.07 to 19.41±0.05. Furthermore, native starch and Cilacap breadfruit RS3 were categorized as high in Amylose. The autoclaving cooling process on Cilacap breadfruit starch effectively increased RS levels, making it a viable alternative for developing functional food

Improvement of Properties of Gelatinization and Retrogradation of Adzuki Bean Starch by Adding Glycolipid

To improve the storage quality of adzuki bean paste from starch aging, the effects of glycolipid addition on the properties of gelatinization and retrogradation properties of adzuki flour obtained by the retrogradation inside adzuki bean during storage and transportation are investigated. The results indicate the significant differences in the gelatinization and the distribution of starch granules for different varieties of beans. The higher gelatinization temperature of adzuki flour results in the lower enthalpy of gelatinization with an undulating tendency of the retrogradation due to the short-term aging of amylose and long-term aging of amylopectin within adzuki flour. In the early stage of aging, the coexistence of protein, fat, and starch inside adzuki flour hinder the aging of starch. An Avrami equation is introduced to characterize the aging process of the starch–protein–fat–water system of different varieties of adzuki flours. The nucleation mode of the crystal nucleus has a significant effect on the aging rate of different varieties of adzuki flour. The fat in the system fails to demonstrate a significant effect on the nucleation mode of starch retrogradation. The addition of glycolipids increases the gelatinization enthalpy of adzuki flour. Glycolipids can reduce the aging degree of adzuki flour, and the inhibition effect on the retrogradation of sucrose monoester is greater than that of maltose monoester. The research results provide the valuable guidance for the high-quality processing and storage of adzuki bean paste from starch aging.

Understanding the multi-scale structure, physicochemical and digestive properties of extruded yam starch with plasma-activated water

In this study, the synergistic effect of plasma-activated water (PAW) combined with twin-screw extrusion (TSE) on multi-scale structure, physicochemical and digestive properties of yam starch (YS) was studied. PAW-TSE resulted in higher amylose content in YS than TSE alone. Compared with single TSE, the relative crystallinity, short-range ordered degree, and gelatinization enthalpy of YS were increased by PAW-TSE according to the results of X-ray diffraction, Fourier transform infrared, Raman spectroscopy, and differential scanning calorimetry. Furthermore, rapid viscosity and dynamic rheological analysis showed that the peak and breakdown viscosity of PAW-TSE treated YS paste were considerably reduced, and the storage modulus and loss modulus were significantly increased, indicating that the gel strength and thermal stability were improved. In addition, the resistant starch (RS) content of YS treated by PAW-TSE increased from 6.04 % to 21.21 %. Notably, the effect of PAW-TSE on YS enhanced with the preparation time of PAW increased. Finally, correlation analysis indicated that the characteristic indexes of PAW had a significant impact on the long or short-range ordered structure, thermal properties, and in vitro digestibility of YS during extrusion. Therefore, PAW-TSE, as an emerging dual modification technology, will greatly expand the application of extrusion technology.