Effect of atmospheric pressure plasma jet on the structure and physicochemical properties of wheat starch

The effect of atmospheric pressure plasma jet (APPJ) with different discharge power (0, 400, 600, and 800 W) on the structure and physicochemical properties of wheat starch were evaluated in this study. After APPJ treatments, significant declines in peak viscosity, breakdown viscosity, and final viscosity of wheat starch pasting parameters were observed with increase of plasma treatment power. Being treated with discharge power of 800 W, the PV and BD value of wheat starch paste significantly dropped to 2,578 and 331 cP, respectively. Apparently, APPJ could raise the solubility of wheat starch, while reduce the swelling capacity, and also lower the G' and G″ value of wheat starch gel. Roughness and apparent scratch was observed on the surface of the treated wheat starch granules. Although APPJ treatment did not alter wheat starch's crystallization type, it abated the relative crystallinity. APPJ treatment might be useful in producing modified wheat starch with lower viscosity and higher solubility.

Effects of Kiwifruit Dietary Fibers on Pasting Properties and In Vitro Starch Digestibility of Wheat Starch

In this study, the roles of kiwifruit soluble/insoluble dietary fiber (SDF/IDF, respectively) in the pasting characteristics and in vitro digestibility of wheat starch were explored. According to RVA and rheological tests, the IDF enhanced the wheat starch viscosity, decreased the gelatinization degree of the starch granules, and exacerbated starch retrogradation. The addition of SDF in high quantities could reduce the starch gelatinization level, lower the system viscosity, and exacerbate starch retrogradation. Through determining the leached amylose content and conducing scanning electron microscopy, the IDF and SDF added in high quantities was combined with the leached amylose wrapped around the starch granules, which reduced the leached amylose content and decreased the gelatinization degree of the starch granules. The Fourier transform infrared results showed that the addition of both the IDF and SDF resulted in an enhancement in hydrogen bonding formed by the hydroxyl groups of the system. The in vitro digestion results strongly suggested that both the IDF and SDF reduced the wheat starch digestibility. The above findings are instructive for the application of both IDF and SDF in starchy functional foods.

Effect of Bletilla Striata Polysaccharide on the Pasting, Rheological and Adhesive Properties of Wheat Starch

A combination of starch and hydrocolloids is a facile method for physically modifying native starch. Bletilla striata polysaccharide (BSP) is a glucomannan with various applications in the food and cosmetic industries as a thickening agent. This study focused on investigating the impact of BSP on the pasting, rheological and adhesive properties of wheat starch (WS). Results from a Rapid Visco-Analyzer (RVA) revealed that the addition of BSP (below 0.2%) resulted in increases in peak viscosity, breakdown and setback values. However, for the addition of BSP at a higher concentration (0.3%), the opposite trend was observed. Rheological measurements indicated that the presence of BSP increased the viscoelastic properties of WS-BSP gels. TGA results demonstrated that the presence of BSP promoted the thermal stability of starch. FTIR results indicated the short-range order structure decreased at low addition concentrations of BSP (0.05% and 0.1%) and increased with higher BSP addition concentrations (0.2% and 0.3%). SEM observation showed that the BSP improved the hydrophilic property of starch gels and decreased the size of pores in the starch gels. Further, the mechanical properties of paper samples unveiled that the present of BSP in starch gels obviously increased its bonding strength as an adhesive.

Different Starch Sources Affect the Growth Performance and Hepatic Health Status of Largemouth Bass (Micropterus salmoides) in a High-Temperature Environment

The experiment was designed to investigate the effects of different starch types on the growth performance and liver health status of largemouth bass in a high-temperature environment (33-35 °C). In this study, we designed five diets using corn starch (CS), tapioca starch (TS), sweet potato starch (SPS), potato starch (PS), and wheat starch (WS) as the starch sources (10%). We selected 225 healthy and uniformly sized largemouth bass (199.6 ± 0.43 g) and conducted the feeding experiment for 45 days. The results showed that the WS group had the highest WGR, SGR, and SR and the lowest FCR. Among the five groups, the WS group had the highest CAT activity, SOD activity, and GSH content, while the SPS group had the highest MDA content. Furthermore, oil red O staining of liver samples showed that the TS group had the largest positive region, indicating high lipid accumulation. Lastly, the gene expression results revealed that compared with the WS group, the CS, TS, and SPS groups showed suppressed expression of nrf2, keap1, cat, sod, gpx, il-8, and il-10. Therefore, our results demonstrated the effect of different starch sources on largemouth bass growth performance and hepatic health in a high-temperature environment.

Thermal, Rheological, Structural and Adhesive Properties of Wheat Starch Gels with Different Potassium Alum Contents

Wheat starch (WS) is a common adhesive material used in mounting of calligraphy and paintings. Potassium alum (PA) has indeed been used for many centuries to modify the physicochemical properties of starch. Thermal analysis revealed that the presence of PA led to an increase in the gelatinization temperature and enthalpy of the starch gels. The leached amylose and the swelling power of the starch gels exhibited a maximum at the ratio of 100:6.0 (WS:PA, w/w). The rheological properties of starch gels were consistent with changes in the swelling power of starch granules. SEM observations confirmed that the gel structure became more regular, and the holes grew larger with the addition of PA below the ratio of 100:6.0 (WS:PA, w/w). The short-range molecular order in the starch gels was enhanced by the addition of PA, confirmed by FT-IR analysis. Mechanical experiments demonstrated that the binding strength of the starch gels increased with higher PA concentrations and decreased significantly after the aging process. TGA results revealed that PA promoted the acid degradation of starch molecules. This study provides a detailed guide for the preparation of starch-based adhesive and its applications in paper conservation.

Tremella Polysaccharide Has Potential to Retard Wheat Starch Gel System Retrogradation and Mechanism Research

This study investigated the effects of adding different concentrations of TP (tremella polysaccharide) on the water distribution, rheological, thermal, microstructure, and retrogradation properties of WS (wheat starch) gels. The results showed that the starch aging increased during storage, and the addition of TP reduced the rate of change of the elastic modulus of the starch gel and delayed the short-term aging of WS. In the same storage period, the hardness value of the gel decreased and the texture became softer with the increase in the mass fraction of TP. TP increased the T0 (starting temperature) of the system and decreased the enthalpy of retrogradation (ΔHr). No new groups were formed after the retrogradation of the compound system, the hydrogen bonding force increased with the increase in polysaccharide, and the relative crystallinity and the degree of ordering of the system decreased. The addition of TP increased the content of bound water and immobile water, decreased the content of free water, and increased the gel water-holding capacity, indicating that it could effectively inhibit the long-term retrogradation of WS. The findings provide new theoretical insights for the production of starch-based foods.

Influence of Persian Gum and Almond Gum on the Physicochemical Properties of Wheat Starch

In this study, the influence of different levels (0.1, 0.2, and 0.3% w/w) of Persian gum or almond gum were incorporated into wheat starch, and their influences on water absorption, freeze-thaw stability, microstructure, pasting, and textural properties were investigated. The SEM micrographs revealed that the addition of hydrocolloids to starch leads to the formation of denser gels with smaller pores. The water absorption of starch pastes was improved in the presence of gums, and samples containing 0.3% almond gum had the highest water absorption. The rapid visco analyzer (RVA) data showed that the incorporation of gums significantly affected the pasting properties by increasing the pasting time, pasting temperature, peak viscosity, final viscosity, and setback and decreasing breakdown. In all the pasting parameters, the changes caused by almond gum were more obvious. Based on TPA measurements, hydrocolloids were able to improve the textural properties of starch gels, such as firmness and gumminess but decreased the cohesiveness, and springiness was not affected by the incorporation of gums. Moreover, the freeze-thaw stability of starch was enhanced by the inclusion of gums, and almond gum exhibited better performance.

Physicochemical properties and molecular structure of starches from different wheat varieties and their influence on Chinese steamed bread

Starch is one of the key factors for the texture of Chinese steamed bread (CSB). In this study, the molecular structures and physicochemical properties of starches from 11 wheat varieties with amylose content (AC) of 1.75%-28.79% were investigated. Northern style CSB was made using these wheat varieties to explore the structure-property-quality relationship of starches. AC was negatively correlated with the pasting and gelatinization properties. The relative crystallinity (RC) had a negative correlation with AC but a positive correlation with gelatinization. The molecular structure results from the fluorophore-assisted capillary electrophoresis spectrophotometer indicated that the length of short amylopectin chains (β_Ap,i ) was positively correlated with hot paste and cool paste viscosities. The amount of medium amylopectin chains (h_Ap,iii ) was positively correlated with peak and breakdown viscosities but negatively correlated with setback viscosity. The h_Ap,iii had positive correlations with gelatinization temperatures and RC. The amount of long amylopectin chains (h_Ap,v ) had a positive correlation with peak temperature. For the CSB texture, β_Ap,i had negative correlations with hardness and chewiness, whereas had a positive correlation with resilience. The h_Ap,iii was negatively correlated with springiness and resilience. The h_Ap,v was negatively associated with resilience. PRACTICAL APPLICATION: Starch has a vital role in wheat flour products. Clarifying the structure-property-quality relationship of starches will help illuminate the role of starch molecular structure in CSB production and provide valuable information for the control of CSB quality. It also provides a significant reference for wheat breeding.

Influence of damaged starch on thermal and rheological properties of wheat starch and wheat starch-gluten systems in water and sucrose

BACKGROUND

The granular integrity of starch granules is affected by the mechanical action of the milling-process, thus producing what is called damaged starch (DS). The effect of DS on bakery products was extensively studied, but there is not much information about the effect of this minor flour component on batter-type products in which there is a high amount of sucrose. The objective of this work was to study the influence of damaged wheat-starch on starch and starch-gluten systems dispersed in water and sucrose 500 g kg^-1 solution.

RESULTS

Thermal and pasting properties and the viscoelastic behavior of the systems were evaluated. Gelatinization enthalpy decreased when DS amount increased in the samples in both solvents. In starch-gluten systems, the degree of influence of DS on the gelatinization enthalpy was solvent-dependent. The presence of gluten minimized the effect of DS on the gelatinization process in water. The viscosity profile of starch and starch-gluten samples was reduced in both solvents when DS level increased. The influence of DS on the viscosity profile was solvent-dependent in starch-gluten systems. The presence of gluten lessened the influence of DS on the viscosity profile during the pasting process in sucrose solution. Higher DS levels decreased the viscoelastic behavior of the systems in both solvents and further reduced the viscoelastic behavior of the systems in sucrose solution.

CONCLUSION

These results contribute to understanding the influence of the DS levels on the batter properties of flour-based batter-type products, mainly those generated on starch and gluten-starch systems dispersed in sucrose solution. © 2022 Society of Chemical Industry.

Effect of Various Plasticizers in Different Concentrations on Physical, Thermal, Mechanical, and Structural Properties of Wheat Starch-Based Films

Biocomposite materials are essential for environmental protection, as they have the ability of substituting synthetic plastic with natural materials. This work investigated how different plasticizers (Glycerol (G), Fructose (F), Sorbitol (S), and Urea (U)) affect the morphological, mechanical, thermal, and physical characteristics of films made of wheat starch at various concentrations (0%, 15%, 25%, and 35%). Plasticizers were added to improve the flexibility and homogeneity of the wheat starch-based bioplastic. Control film exhibited high tensile strength (38.7 MPa) with low elongation (1.9%). However, films plasticized with 35% sorbitol showed the highest elongation, which was 60.7% at break. At 35% of all plasticizers, fructose showed the highest tensile strength, with 7.6 MPa. The addition of different plasticizers shows improvement in water resistance; films plasticized with glycerol had the lowest water absorption at 35% fructose (187.4%) and also showed coherent surfaces. Glycerol, sorbitol, and urea films showed a higher mass loss compared to fructose films. Fructose showed the highest performance after the analysis of the results, with low water absorption, water content, and mass loss and with high mechanical performance at 35% of fructose. SEM images show that the addition of fructose and glycerol improves the surface homogenate, while sorbitol and urea have a less compact structure with large pores.

Effects of Hydroxypropyl and Lactate Esterified Glutinous Rice Starch on Wheat Starch Gel Construction

An investigation was conducted into the impacts of hydroxypropyl glutinous rice starch (HPGRS) and lactate-esterified glutinous rice starch (LAEGRS) on a dilute solution and gel properties of wheat starch (WS) at different proportions (0%, 1%, 3%, 5%, and 10%). The results of dilute solution viscosity showed that hydroxypropyl treatment of glutinous rice starch (GRS) could promote the extension of GRS chains, while lactate esterification led to the hydrophobic association of GRS chains, and the starch chains curled inward. Different HPGRS: WS and LAEGRS: WS ratios, β > 0 and ∆b > 0, showed HPGRS and LAEGRS produced attractive forces with WS and formed a uniform gel structure. Compared with WS gel, HPGRS, and LAEGRS could effectively delay the short-term aging of WS gels, and LAEGRS had a more significant effect. HPGRS increased the pasting viscosity, viscoelasticity, and springiness of WS gels, reduced the free water content, and established a tighter gel network structure, while LAEGRS had an opposite trend on WS. In conclusion, HPGRS was suitable for WS-based foods with stable gel network structure and high water retention requirements, and LAEGRS was suitable for WS-based foods with low viscosity and loose gel structure.

Gelatinization, Retrogradation and Gel Properties of Wheat Starch-Wheat Bran Arabinoxylan Complexes

Gelatinization, retrogradation and gel properties of wheat starch–wheat bran arabinoxylan (WS–WBAX) complexes have been evaluated. The results of rapid viscosity analyzer (RVA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) confirmed that WBAX samples with larger Mw and branching degree (HWBAX) significantly impeded gelatinization process of starch by effectively reducing the amount of water available for starch gelatinization. DSC analysis showed that both molecular characteristics and additive amount of WBAX samples have an effect on the long-term retrogradation behavior of starch. For the rheological studies of WS–WBAX mixed gels, the elastic moduli (G’) and shear viscosity of WS–WBAX mixed gels increased with the increase in additive amount of WBAX. WS–HWBAX mixed gels exhibited the lower G’ compared with starch gels containing WBAX with lower Mw and branching degree (LWBAX) at the same amount. The scanning electron micrographs (SEM) revealed that the microstructures of WS–WBAX mixed gels were mainly affected by the amount of WBAX, but hardly by the molecular characteristics of WBAX. Texture profile analysis (TPA) showed that the cohesiveness of fresh WS–WBAX mixed gels became larger with an increase in the WBAX addition amount. The hardness of WS–WBAX mixed gels tended to increase over the 14-day storage.

Wheat Biocomposite Extraction, Structure, Properties and Characterization: A Review

Biocomposite materials create a huge opportunity for a healthy and safe environment by replacing artificial plastic and materials with natural ingredients in a variety of applications. Furniture, construction materials, insulation, and packaging, as well as medical devices, can all benefit from biocomposite materials. Wheat is one of the world’s most widely cultivated crops. Due to its mechanical and physical properties, wheat starch, gluten, and fiber are vital in the biopolymer industry. Glycerol as a plasticizer considerably increased the elongation and water vapor permeability of wheat films. Wheat fiber developed mechanical and thermal properties as a result of various matrices; wheat gluten is water insoluble, elastic, non-toxic, and biodegradable, making it useful in biocomposite materials. This study looked at the feasibility of using wheat plant components such as wheat, gluten, and fiber in the biocomposite material industry.

Effects of Citrus Peel Hydrolysates on Retrogradation of Wheat Starch

Retrogradation is the principal cause for bread staling and, therefore, it has attracted a lot of interest from the food industry. In this study, the inhibitory effect of citrus peel hydrolysates (CPH) on retrogradation of wheat starch (WS) in the presence of sucrose was investigated. The pasting properties showed that further addition of CPH caused a lower setback value than the addition of sucrose alone. Hardness of the gel, retrograded at 4 °C for five days, showed a similar tendency, which was reduced more in CPH addition than WS itself or sucrose addition alone. The low retrogradation enthalpy of the CPH including starch gel also indicated the positive effect of CPH on retarding retrogradation. These results suggested that incorporation of CPH in starch-based foods would be effective for inhibiting retrogradation, preventing the deterioration of the quality of food products.

Effects of two contrasting dietary polysaccharides and tannic acid on the digestive and physicochemical properties of wheat starch

In this study, konjac glucomannan, κ-carrageenan, and tannic acid were selected to study the effects of different combinations on the in vitro digestibility and physicochemical properties of wheat starch. Results showed that the addition of konjac glucomannan, κ-carrageenan, and tannic acid could decrease the digestion of starch and increase the content of resistant starch. Besides, the two polysaccharides weakened the extent of tannic acid on starch digestion. Moreover, although the two polysaccharides had different effects on the in vitro digestion of starch, they had no significant increase in the content of resistant starch. DSC and XRD results demonstrated that the polysaccharides and tannic acid showed synergistic effects on the rebuilding of starch microstructure. FTIR results further manifested that κ-carrageenan and konjac glucomannan could significantly increase the strength of hydrogen bonds in starch. At the same time, the addition of tannic acid would weaken the molecular interaction between polysaccharides and starch. SEM and CLSM results showed that tannic acid added to the polysaccharide-starch mixture not only interacted with starch but also influenced the structure of polysaccharide gel.

Application of high-pressure homogenization to tailor the functionalities of native wheat starch

BACKGROUND

The effect of high-pressure homogenization (HPH) on the rheological and thermal properties, water retention capacity (WRC), morphology and in vitro digestion of wheat starch was evaluated. Starch suspensions (50 g kg^-1 , w/w) were treated at increasing pressures (up to 100 MPa) and numbers of cycles (up to 5) to generate a wide range of energy densities (70-500 MJ m^-3 ) delivered to the sample during processing.

RESULTS

High-pressure homogenization induced a partial starch gelatinization confirmed by higher digestibility. Gelatinization degree (GD) was between 13% and 83%, causing a wide range of functional properties. High-pressure homogenization-treated starch samples showed WRC values of 810-1910 g kg^-1 . Storage modulus (G') and complex viscosity (η^* ) of starch dispersions were almost two and three times higher than the control at 13% and 83% GD, respectively. Positive linear relationships between GD (R = 0.98, P < 0.001), WRC (R = 0.87, P < 0.05), or rheological parameters (R = 0.89÷0.90, P < 0.01) and energy density of HPH treatments were found.

CONCLUSION

High-pressure homogenization treatment represents a promising technology to obtain wheat starch with tailored rheological properties and digestibility, which allows the texture and glycemic response of food products to be adjusted. © 2020 Society of Chemical Industry.

Studies on functional properties of wheat starch in the presence of Lepidium perfoliatum and Alyssum homolocarpum seed gums

This study was performed to investigate the influence of Lepidium perfoliatum seed gum (LPSG) and Alyssum homolocarpum seed gum (AHSG) on functional properties of wheat starch. Various concentrations of gums (0.25%, 0.5%, 0.75%, and 1% dry starch weight basis) were added to wheat starch, and their influences on water absorption, pasting properties, gel strength, freeze-thaw stability and color parameters were investigated. The results showed that both gums improved water absorption, freeze-thaw stability, pasting parameters, gel hardness, gumminess, and chewiness whereas springiness was not affected and cohesiveness was decreased by the incorporation of gums and LPSG more effective than AHSG. Color parameters were also affected by the concentration of gums. The L value decreased whereas a value and b value increased in the presence of both gums. However, the changes were more obvious in samples containing LPSG. PRACTICAL APPLICATION: Starch is one of the most important carbohydrate materials in the food industry. However, native starch has shortcomings, such as sensitivity to shear or syneresis that limit its applications in food processing. Incorporation of hydrocolloids is an effective strategy to improve functional properties of starch. LPSG and AHSG are two novel sources of hydrocolloids which can be used to modify the properties of starch in food products.

Use of Amylomaltase to Steer the Functional and Nutritional Properties of Wheat Starch

The fine molecular structure of starch governs its functionality and digestibility, and enzymatic approaches can be utilized to tailor its properties. The aim of this study was to investigate the in situ modification of starch by amylomaltase (AMM) from Thermus thermophilus in model starch systems subjected to hydrothermal treatments under standardized conditions and the relationship between molecular structure, rheological properties and in vitro digestibility. When low dosages of AMM were added to a wheat starch suspension prior to submitting it to a temperature-time profile in a Rapid Visco Analyzer, the increased peak viscosity observed was attributed to partial depolymerization of amylose, which facilitated starch swelling and viscosity development. At higher dosages, the effect was smaller. The low cold paste viscosity as a result of the activity of AMM reflected substantial amylose depolymerization. At the same time, amylopectin chains were substantially elongated. The longer amylopectin chains were positively correlated (R² = 0.96) with the melting enthalpies of retrograded starches, which, in turn, were negatively correlated with the extent (R² = 0.92) and rate (R² = 0.79) of in vitro digestion. It was concluded that AMM has the potential to be used to deliver novel starch functionalities and enhance its nutritional properties.

Suitability and Modification of Different Renewable Materials as Feedstock for Sustainable Flame Retardants

Due to their chemical structure, conventional flame retardants are often toxic, barely biodegradable and consequently neither healthy nor environmentally friendly. Their use is therefore increasingly limited by regulations. For this reason, research on innovative flame retardants based on sustainable materials is the main focus of this work. Wheat starch, wheat protein, xylan and tannin were modified with phosphate salts in molten urea. The functionalization leads to the incorporation of phosphates (up to 48 wt.%) and nitrogen (up to 22 wt.%). The derivatives were applied on wood fibers and tested as flame retardants. The results indicate that these modified biopolymers can provide the same flame-retardant performances as commercial compounds currently used in the wood fiber industry. Besides, the flame retardancy smoldering effects may also be reduced compared to unmodified wood fibers depending on the used biopolymer. These results show that different biopolymers modified in phosphate/urea systems are a serious alternative to conventional flame retardants.

Effects of the size distribution of wheat starch on noodles with and without gluten

To understand the effects of A- and B-type wheat starch on noodle quality, two noodle models with (Model 1) and without (Model 2) gluten were constructed with five different ratios of A- to B-granules (100A-0B, 75A-25B, 50A-50B, 25A-75B, and 0A-100B). With increasing proportions of B-granules, the noodle structures of Models 1 and 2 became increasingly dense. The cooking loss, water absorption, proportion of free water, chewiness, cohesiveness and resilience decreased from 35.64 to 15.49%, 240.92 to 228.58%, 88.89 to 85.98%, 21.93 to 13.24 N, 0.77 to 0.56, and 0.61 to 0.36, respectively, with the increased proportion of B-granules in Model 2, while those parameters normally presented "V" or inverted "V" trends in Model 1. Compared to their counterparts in Model 2, gluten networks with 25-50% B-granules had an outstanding ability to increase the percentage of tightly bound water, hardness, chewiness and springiness by 4.50%, 24.07 N, 25.05 N, and 0.17 at most and reduce the proportion of free water and water absorption by 5.56 and 73.70% at most, respectively. The results indicated that the effect of the gluten network on noodle qualities may partially depend on its structure, which is shaped by the granule size distribution. Compared to the other characteristics of noodles, the springiness was influenced by a more complicated mechanism involving A- and B-granules in Model 2, while it was strongly affected by the gluten network under the given experimental conditions in Model 1.

Hypoglycemic effect of soluble polysaccharide and catechins from green tea on inhibiting intestinal transport of glucose

BACKGROUND

Water soluble polysaccharide derived from green tea (WSP) is produced as byproducts when catechins were extracted from green tea. Although inhibitory effect of green tea catechins on the glucose transport in small intestine has been studied, the hypoglycemic efficacy of the WSP or its combinational effect has not been studied. In order to investigate hypoglycemic efficacy of the WSP or its combinational effect with green tea extract (GTE), co-consumption of GTE and WSP with wheat starch was investigated using in vitro digestion coupled with Caco-2 cells. The mechanism of the intestinal glucose transport was elucidated throughout the gene expression of the intestinal glucose transporters, which included sodium dependent glucose transporter (SGLT1) and glucose transporter 2 (GLUT2), using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The co-digestion of wheat starch with GTE during the small intestinal phase was the most rapidly digested into reducing sugar (73.96 g L^-1 ) compared to itself (48.44 g L^-1 ), WSP (60.35 g L^-1 ), and GTE + WSP (61.81 g L^-1 ). Intestinal glucose transport was 11.82, 7.59, 4.49, and 2.40% for wheat starch, wheat starch with GTE, WSP, and GTE + WSP, respectively. The highest decreased expression pattern in SGLT1 was observed when cells treated with wheat starch + GTE + WSP (0.66-fold) compared to GTE or WSP treatment.

CONCLUSION

The results suggested that co-consumption of green tea derived products with wheat starch could delay the intestinal absorption of glucose. Results from the current study suggested that GTE and WSP could be the useful supplements of dietary therapy for hyperglycemia to delay glucose absorption. © 2020 Society of Chemical Industry.

Effect of the wheat starch/wheat protein ratio in a batter on fat absorption and quality attributes of fried battered and breaded fish nuggets

Battered and breaded fish nuggets (BBFNs) were prepared by treating fish with a batter composed of wheat starch (WS) and wheat protein (WP) blends (at the ratios of 15:1, 13:1, 11:1, 9:1, and 7:1, w/w), frying at 170 °C (40 s) followed by 190 °C (30 s). Fried BBFNs were evaluated for moisture and fat contents, color, shrinkage, acrylamide content, and fat distribution. Results showed that moisture content and brightness (L^* value from colorimetry) increased with a decrease of WS/WP ratio to 11:1 w/w, then decreased as WS/WP ratio further decreased, while fat content, fat distribution level, and shrinkage of fried BBFNs presented opposite results. However, there was a slight influence of WS/WP ratio on yellowness (b^* value), redness (a^* value), and acrylamide content of fried BBFNs. Among WS/WP ratios, fried BBFNs with 11:1 w/w have the highest moisture content (16.43%) and the lowest fat content (23.39%), fat distribution level, shrinkage (10.72%), and acrylamide content (57 mg/kg), while a crust with golden-yellow color was observed. This study demonstrates that moisture evaporation and fat absorption were significantly influenced by WS/WP ratio in the batter (P < 0.05), with the most effective results in quality attributes improvement of fried BBFNs. PRACTICAL APPLICATION: This study clearly showed that the fat content and quality attributes of fried BBFNs were significantly affected by WS/WP ratio in the batter (P < 0.05). The inhibition of fat absorption and improvement of shrinkage and color in fried BBFNs was the most effective for a 11:1 w/w WS/WP ratio.

The influence of Konjac glucomannan on the functional and structural properties of wheat starch

The aim of this study was to characterize the influence of Konjac glucomannan (KGM) on the functional and structural properties of wheat starch. Results showed that KGM significantly decreased the starch hydrolysis rate, with a lower level of rapidly digestible starch (RDS), and a higher content of slowly digestible starch (SDS). Besides, KGM decreased the content of leached amylose, while enhanced the swelling power, water-holding capacity, freeze-thaw stability, and paste clarity of wheat starch, which indicated a good improvement on the functional properties. Differential scanning calorimetry (DSC) and X-ray diffraction patterns (XRD) manifested that the addition of KGM disrupted the original crystalline structures of wheat starch, which may result in the increased hydrolysis rate of starch. Interestingly, this did not consist with the decreased starch hydrolysis rate showed in the study. Moreover, FTIR results showed the existence of the interaction between KGM and starch. The morphological characterization demonstrated that the addition of KGM contributed to a more compact structure of freeze-dried wheat starch. And KGM inhibited the expansion of starch granules and formed a barrier around the gelatinized starch. Therefore, the barrier around the starch granules and the interaction between KGM and starch were considered to be the important reasons that affected the starch digestibility.

Polysaccharide-Based Injection Matrix for Serial Crystallography

Serial crystallography (SX) provides an opportunity to observe the molecular dynamics of macromolecular structures at room temperature via pump-probe studies. The delivery of crystals embedded in a viscous medium via an injector or syringe is widely performed in synchrotrons or X-ray free-electron laser facilities with low repetition rates. Various viscous media have been developed; however, there are cases in which the delivery material undesirably interacts chemically or biologically with specific protein samples, or changes the stability of the injection stream, depending on the crystallization solution. Therefore, continued discovery and characterization of new delivery media is necessary for expanding future SX applications. Here, the preparation and characterization of new polysaccharide (wheat starch (WS) and alginate)-based sample delivery media are introduced for SX. Crystals embedded in a WS or alginate injection medium showed a stable injection stream at a flow rate of < 200 nL/min and low-level X-ray background scattering similar to other hydrogels. Using these media, serial millisecond crystallography (SMX) was performed, and the room temperature crystal structures of glucose isomerase and lysozyme were determined at 1.9–2.0 Å resolutions. WS and alginate will allow an expanded application of sample delivery media in SX experiments.

Effect of Artemisia sphaerocephala Krasch polysaccharide on the gelatinization and retrogradation of wheat starch

The effect of Artemisia sphaerocephala Krasch polysaccharide (ASKP) on the gelatinization and retrogradation of wheat starch (WS) was studied. RVA results displayed that ASKP addition increased the setback values of WS, which indicated that ASKP might promote the short-term retrogradation of WS. DSC and XRD results demonstrated that the retrogradation percentage of WS during long-time storage significantly decreased with the addition of ASKP, suggesting the inhibition effect of ASKP on the long-term retrogradation of WS. As shown in TPA test, ASKP addition increased the hardness of starch gel at the beginning but decreased it after 14 days' storage. Results of FT-IR revealed that ASKP could promote the water retention and intermolecular hydrogen bonding formation. With the addition of ASKP, the spin-spin relaxation time measured by LF-NMR decreased from 358.47 ms to 274.15 ms, illustrating that the WS paste containing ASKP had higher water retention ability. Leached amylose content results manifested the interaction between WS and ASKP. In summary, ASKP has potential to be a modifier on the retrogradation of starch in food processing.

Effect of Heat-Moisture Treatment on Physicochemical, Thermal, Morphological, and Structural Properties of Mechanically Activated Large A- and Small B-Wheat Starch Granules

The large and small granules of A-starch (AS) and B-starch (BS) were separated from wheat cultivar of ZM 22. It was modified by ball-milling (BM) and heat-moisture treatment (HMT) was performed after BM treatment. After BM, noticeable deformation, fragments, fissures, and grooves were observed, whereas diffusion and aggregation were detected and followed by HMT. Crystallinity of AS-BM-5h decreased to 7.8%, and no diffraction peaks were observed for BS. However, after HMT, the crystallinity of AS-BM-5h and BS-BM-5h was increased to 17.4% and 6.2%, respectively. AS-BM-HMT displayed better thermal stability. After being treated by BM previously, AS and BS showed an increase in solubility, whereas the subsequent HMT of BM-treated starches (both AS and BS) had higher solubility especially for BS with longer BM treatment time. Large-sized granules were easier to be damaged by BM, whereas small-sized granules were greatly influenced by HMT. Dual modification of BM-HMT was an effective and potential method to modify the structure of wheat starch granules and expand its industrial applications. PRACTICAL APPLICATION: This study put forward a new dual modification method in combination with BM-HMT for large A-starch and small B-starch granules. Flour processing inevitably causes some starch to be damaged by destroying the structure. How can the damaged starch structure be improved to satisfy the food processing industry? HMT was proposed to modify the mechanically activated starches because of its obvious effects on smaller BS. HMT can reduce the content of damaged starch by rearranging and reorganizing its structures. This study can provide a low-cost, convenient, and eco-friendly technology for improving damaged starch and developing its applications in food industry.

Dual-frequency ultrasound for ultrasonic-assisted esterification

The optimization of wheat starch esterification (acetylation) with a high degree of substitution was performed through response surface methodology (RSM) via various concentrations of reagents (acetic anhydride), pHs, and temperatures under various ultrasonication frequencies (25, 40, and 25 + 40 kHz). According to RSM methodology, optimized samples were selected by achieving high degrees of substitution at various frequencies, temperatures, and pHs. Solubility, swelling, X-ray, RVA, DSC, freeze-thaw stability, texture, and SEM analysis of the optimized samples were performed at three frequencies. X-ray pattern exhibited a more significant reduction in the crystallinity percentage of esterified starch at frequency 25 + 40 kHz compared with 25 kHz, 40 kHz, and native starch. According to DSC analysis, To, Tp, Tc, and enthalpy of gelatinization (ΔH gel) were lower in AC at frequency 25 + 40 kHz compared with AC at frequency 25 and 40 kHz and N starches. According to morphology analysis, in acetylated starches at 25 and 40 kHz, the surfaces and small granules underwent more damage, whereas in 25 + 40 kHz, large granules were more affected than small granules. Upon acetylation, freeze-thaw stability and textural properties of the starch significantly increased and decreased, respectively. The peak and final viscosity of acetylated starch increased (25 + 40 kHz ˃ 25 kHz ˃ 40 kHz ˃ N starch).

Dual-frequency ultrasound for ultrasonic-assisted esterification

The optimization of wheat starch esterification (acetylation) with a high degree of substitution was performed through response surface methodology (RSM) via various concentrations of reagents (acetic anhydride), pHs, and temperatures under various ultrasonication frequencies (25, 40, and 25 + 40 kHz). According to RSM methodology, optimized samples were selected by achieving high degrees of substitution at various frequencies, temperatures, and pHs. Solubility, swelling, X-ray, RVA, DSC, freeze-thaw stability, texture, and SEM analysis of the optimized samples were performed at three frequencies. X-ray pattern exhibited a more significant reduction in the crystallinity percentage of esterified starch at frequency 25 + 40 kHz compared with 25 kHz, 40 kHz, and native starch. According to DSC analysis, To, Tp, Tc, and enthalpy of gelatinization (ΔH gel) were lower in AC at frequency 25 + 40 kHz compared with AC at frequency 25 and 40 kHz and N starches. According to morphology analysis, in acetylated starches at 25 and 40 kHz, the surfaces and small granules underwent more damage, whereas in 25 + 40 kHz, large granules were more affected than small granules. Upon acetylation, freeze-thaw stability and textural properties of the starch significantly increased and decreased, respectively. The peak and final viscosity of acetylated starch increased (25 + 40 kHz ˃ 25 kHz ˃ 40 kHz ˃ N starch).

The influence of bath and probe sonication on the physicochemical and microstructural properties of wheat starch

Ultrasound has been rapidly applied successfully in diverse food technological aspects including improvement of functional properties of food ingredients such as starch. This work was carried out to compare the influence of two types of sonication, bath and probe, on several physicochemical and microstructural properties of wheat starch. Two sonication probes (200 and 400 W) and a sonication bath (690 W) were applied to treat wheat starch suspensions at 15 and 30 min. Sonication time in 400 W probe was intermittent while for the other treatments, it was continuous. Swelling capacity (SC), solubility (SB), turbidity (TB), and oil absorption (OA) parameters were investigated for native (control) and sonicated wheat starch. Moreover, scanning electron microscopy (SEM) was performed to determine the influence of sonication treatments on the morphology of wheat starch granules. The highest level of SB and OA, as well as the lowest SC, was obtained for starch samples treated with 200 W sonication probe, while no significant difference (p < 0.05) was observed between two sonication times (15 and 30 min). The SEM images showed significant and nonuniform impact of ultrasound on the structure of starch granules in which some granules remained almost smooth, but some showed high irregular surfaces or even in some cases structure collapse. The highest disintegration of granules was obtained in probe 200 W treatments.

Mechanically and Thermally Induced Degradation and Modification of Cereal Biopolymers during Grinding

It is presumed that structural and functional alterations of biopolymers, which occur during grinding, are caused by a mechanical modification of polymers. As a result, thermally induced changes of flours are neglected. In this study, the impact of thermo-mechanical stress (TMS), as occurring during general grinding procedures, was further differentiated into thermal stress (TS) and mechanical stress (MS). For TS, native wheat flour, as well as the purified polymers of wheat—starch and gluten—were heated without water addition up to 110 °C. Isolated MS was applied in a temperature-controlled ultra-centrifugal grinder (UCG), whereby thermal and mechanical treatment (TMS) was simultaneously performed in a non-cooled UCG. TS starch (110 °C) and reference starch did not show differences in starch modification degree (2.53 ± 0.24 g/100 g and 2.73 ± 0.15 g/100 g, AACC 76-31), gelatinization onset (52.44 ± 0.14 °C and 52.73 ± 0.27 °C, differential scanning calorimetry (DSC)) and hydration properties (68.9 ± 0.8% dm and 75.8 ± 3.0%, AACC 56-11), respectively. However, TS led to an elevated gelatinization onset and a rise of water absorption of flours (Z-kneader) affecting the processing of cereal-based dough. No differences were visible between MS and TMS up to 18,000 rpm regarding hydration properties (65.0 ± 2.0% dm and 66.5 ± 0.3% dm, respectively). Consequently, mechanical forces are the main factor controlling the structural modification and functional properties of flours during grinding.

In Vitro Digestibility of Nanoporous Wheat Starch Aerogels

This study reports the in vitro digestibility of starch aerogels for the first time. The relative crystallinities of the wheat starch aerogels (WSAs) produced at gelatinization temperatures of 120 °C (WSA-120C), 130 °C (WSA-130C), and 120 °C with the addition of sodium metaphosphate (STMP) (WSA-STMP) and xerogel were similar. However, WSA-120C showed the highest amylose-lipid complex content. The addition of STMP created some cross-linked starch with a phosphorus content of 0.023%. Resistant starch (RS) contents of WSA-STMP (33.5%) and xerogel (26.9%) were higher than the other samples when they were uncooked prior to digestion. Nevertheless, the RS contents of WSA-STMP and xerogel decreased drastically with cooking. RS contents of WSA-120C and WSA-130C were stable with cooking and provided 4.5- and 3.0-fold increases in the RS content, respectively. WSA is a promising functional food ingredient with a high RS content, even after cooking.

Formation of macromolecules in wheat gluten/starch mixtures during twin-screw extrusion: effect of different additives

BACKGROUND

Wheat gluten comprises a good quality and inexpensive vegetable protein with an ideal amino acid composition. To expand the potential application of wheat gluten in the food industry, the effect of different additives on the physicochemical and structural properties of wheat gluten/starch mixtures during twin-screw extrusion was investigated.

RESULTS

Macromolecules were observed to form in wheat gluten/starch mixtures during twin-screw extrusion, which may be attributed to the formation of new disulfide bonds and non-covalent interactions, as well as Maillard reaction products. Additionally, the water retention capacity and in vitro protein digestibility of all extruded wheat gluten/starch products significantly increased, whereas the nitrogen solubility index and free sulfhydryl group (SH) content decreased, during twin-screw extrusion. Secondary structural analysis showed that α-helices disappeared with the concomitant increase of antiparallel β-sheets, demonstrating the occurrence of protein aggregation. Microstructures suggested that the irregular wheat gluten granular structure was disrupted, with additive addition favoring transformation into a more layered or fibrous structure during twin-screw extrusion.

CONCLUSION

The findings of the present study demonstrate that extrusion might affect the texture and quality of extruded wheat gluten-based foods and suggest that this process might serve as a basis for the high-value application of wheat gluten products. © 2017 Society of Chemical Industry.

Identification of Differentially Expressed Micrornas Associate with Glucose Metabolism in Different Organs of Blunt Snout Bream (Megalobrama amblycephala)

Blunt snout bream (Megalobrama amblycephala) is a widely favored herbivorous fish species and is a frequentlyused fish model for studying the metabolism physiology. This study aimed to provide a comprehensive illustration of the mechanisms of a high-starch diet (HSD) induced lipid metabolic disorder by identifying microRNAs (miRNAs) controlled pathways in glucose and lipid metabolism in fish using high-throughput sequencing technologies. Small RNA libraries derived from intestines, livers, and brains of HSD and normal-starch diet (NSD) treated M. amblycephala were sequenced and 79, 124 and 77 differentially expressed miRNAs (DEMs) in intestines, livers, and brains of HSD treated fish were identified, respectively. Bioinformatics analyses showed that these DEMs targeted hundreds of predicted genes were enriched into metabolic pathways and biosynthetic processes, including peroxisome proliferator-activated receptor (PPAR), glycolysis/gluconeogenesis, and insulin signaling pathway. These analyses confirmed that miRNAs play crucial roles in glucose and lipid metabolism related to high wheat starch treatment. These results provide information on further investigation of a DEM-related mechanism dysregulated by a high carbohydrate diet.

Effects of carbohydrate/protein ratio on the microstructure and the barrier and sorption properties of wheat starch-whey protein blend edible films

BACKGROUND

Starch and whey protein isolate and their mixtures were used for making edible films. Moisture sorption isotherms, water vapour permeability, sorption of aroma compounds, microstructure, water contact angle and surface properties were investigated.

RESULTS

With increasing protein content, the microstructure changes became more homogeneous. The water vapour permeability increases with both the humidity gradient and the starch content. For all films, the hygroscopicity increases with starch content. Surface properties change according to the starch/whey protein ratio and are mainly related to the polar component of the surface tension. Films composed of 80% starch and 20% whey proteins have more hydrophobic surfaces than the other films due to specific interactions.

CONCLUSIONS

The effect of carbohydrate/protein ratio significantly influences the microstructure, the surface wettability and the barrier properties of wheat starch-whey protein blend films. © 2016 Society of Chemical Industry.

Improved Quantitation of Gluten in Wheat Starch for Celiac Disease Patients by Gel-Permeation High-Performance Liquid Chromatography with Fluorescence Detection (GP-HPLC-FLD)

Purified wheat starch (WSt) is commonly used in gluten-free products for celiac disease (CD) patients. It is mostly well-tolerated, but doubts about its safety for CD patients persist. One reason may be that most ELISA kits primarily recognize the alcohol-soluble gliadin fraction of gluten, but insufficiently target the alcohol-insoluble glutenin fraction. To address this problem, a new sensitive method based on the sequential extraction of gliadins, glutenins, and gluten from WSt followed by gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD) was developed. It revealed that considerable amounts of glutenins were present in most WSt. The gluten contents quantitated by GP-HPLC-FLD as sum of gliadins and glutenins were higher than those by R5 ELISA (gluten as gliadin content multiplied by a factor of 2) in 19 out of 26 WSt. Despite its limited selectivity, GP-HPLC-FLD may be applied as confirmatory method to ELISA to quantitate gluten in WSt.

Functional properties of wheat starch with different particle size distribution

BACKGROUND

Functional properties of wheat starches with different particle size distribution were investigated.

RESULTS

A-granules displayed a disc shape and B-granules displayed a spherical shape. A-granules had the highest conclusion temperature (Tc , 80.28 °C) and gelatinisation enthalpy (3.268 J g(-1)) and B-granules had the highest peak temperature (Tp, 66.00 °C) and the lowest gelatinisation enthalpy (2.237 J g(-1)). The gelatinisation onset temperature (To), the peak temperature (Tp), Tc and retrogradation of mixed starches increased with the increase of the ratio of B-granules, while the enthalpy, all the viscosity parameters and syneresis of mixed starches decreased with the increase of the ratio of B granules. B-granules had a higher pasting temperature. The sample of B/A = 0.5/10 had the highest peak, breakdown and final viscosity. The percentage of water separated from B-granule gels was minimal, indicated that B-type gels were more stable than other samples. The ΔH2 of A-granules was obviously higher than that of B-granules. However, during storage, the ΔH2 of the starch paste was dramatically increased and the ΔH2 of B-granules was obviously higher than that of A-granules.

CONCLUSION

B-granules were easier to age than A-granules and most of the properties of wheat starches varied significantly with the ratio of B-granules. The relationship between structure and functionality of wheat starch received further verification.