An insight into the retrogradation behaviors and molecular structures of lotus seed starch-hydrocolloid blends

Insights into the effects of fucoidan and caffeic acid on pasting, thermal, rheological, freeze-thaw and structural properties of cassava starch

Fucoidan (FU) and caffeic acid (CA) can modify the physicochemical properties of starch and confer various health-beneficial functional characteristics to cassava starch (CS) products. This study utilized Rapid Visco Analyzer (RVA), Differential Scanning Calorimetry (DSC), rheometer, Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) to investigate the effects of FU andCA on the gelatinization, rheological properties, freeze-thaw stability, and structural characteristics of CS. Results from RVA showed that FU boosted the free expansion, shear resistance and gel thermal stability of CS while reducing their gel formation capacity and delaying short-term retrogradation. CA decreased the free expansion, shear resistance and gel formation ability of CS while delaying the short-term retrogradation of CS. The analysis of DSC showed that FU and CA could decrease the gelatinization enthalpy of CS. The rheological results revealed that each gel system was typical weak gel and pseudoplastic fluid. Both FU and CA weakened the relative motion of amylose molecules and reduced the energy required to disrupt the CS gel system. FU significantly enhanced the pseudoplasticity of CS gel (upward: 0.48 to 0.44; downward: 0.566 to 0.488, p < 0.05), whereas CA significantly decreased the thickening ability in the upward stage. FU and CA increased the hardness of CS gel (except 2.5 % CA). Furthermore, the addition of FU and CA was not conducive to the improvement of freeze-thaw stability of CS gel. FT-IR and XRD analyses exhibited that non-covalent bond mediated the effect of FU and CA on CS gel. SEM observations showed that FU and CA induced the formation of denser "honeycomb" pores in the CS gel. Both FU and CA were found to effectively retard the short-term retrogradation of CS, while enhancing the microstructural integrity of the gel network. These findings suggested that the incorporation of FU and CA could be utilized as a means to modulate the quality attributes of cassava starch-based products.

Effects of Porphyra haitanensis polysaccharides on the short-term retrogradation and simulated digestion in vitro of three crystalline starches

In this study, the effects of Porphyra haitanensis polysaccharides (PHP) (0.4 %, 0.8 % and 1.2 %) on the short-term retrogradation and simulated digestion in vitro properties of starches with corn starch (CS), potato starch (PS) and lotus seed starch (LS) and their potential mechanism of PHP were constructed. 0.4 % and 0.8 % PHP promoted the formation of ordered structures in PS, and all PHP suppressed short-range ordered structure rearrangements in CS and LS. PHP promoted PS-PHP complex while retarding water migration of CS-PHP and LS-PHP complex. XRD showed that all PHP inhibited the short-term retrogradation of CS and LS while facilitating PS. Finally, compared to native starch, CS-0.4%PHP, CS-0.8%PHP, LS-0.8%PHP and LS-1.2%PHP had higher hydrolysis rate, but PHP could decrease that of PS. All of PHP were decreased the RS proportion of CS and LS, especially CS-0.8%PHP, LS-0.8%PHP and LS-1.2%PHP. While PHP were increased that of PS. These results will provide a scientific basis for the development of starch-based foods.

Chlamydomonas reinhardtii polysaccharides retard rice starch retrogradation by weakening hydrogen bond strength within starch double helices

This study investigated the effects of Chlamydomonas reinhardtii polysaccharides (CRPs) on retarding the retrogradation of japonica rice starch (JS) and glutinous rice starch (GS). Structure characterization revealed that CRPs, with an average molecular weight of 505 kDa, mainly consisted of glucose, mannose, and galactose and featured a triple-helix structure. CRPs could reduce the storage modulus increment of JS during the cooling process by interacting with amylose, thereby inhibiting gel network formation. After long-term storage, CRPs decreased the hardness of JS and GS gels, limited the mobility of water molecules, and inhibited dehydration of gels. In addition, CRPs restricted starch recrystallization through interactions with amylopectin, resulting in reduced retrogradation enthalpy and relative crystallinity in JS and GS gels. Further investigation revealed that CRPs could weaken hydrogen bond strength within double helices in JS and GS after 14 days, with bond energies of 10.270 kJ for JS-0.4%CRPs and 10.241 kJ for GS-0.4%CRPs, which are lower than those of native starches (10.464 and 10.500 kJ). Moreover, the energy increments of hydrogen bonds within double helices in complexes were smaller than those of native rice starches during storage, which emerges as the essential reason behind the retardation of rice starch retrogradation by CRPs.

Controlling pea starch gelatinization behavior and rheological properties by modulating granule structure change with pea protein isolate

The purpose of this study was to investigate how the gelatinization behavior of pea starch (PS) was affected by pea protein isolate (PPI). The findings revealed that higher PPI levels decreased the swelling power of PS. Incorporating PPI raised the hot paste viscosity of PS, lowered the pasting temperature, and notably increased the gelatinization enthalpy according to differential scanning calorimetry analysis. Furthermore, the presence of PPI reduced the storage moduli of the starch paste, enhanced shear thinning behavior, and hindered starch molecular chain aggregation. With increasing PPI content from 0 to 12 %, amylose leaching and gel strength decreased by 25.6 % and 38.2 % respectively, indicating weak gel formation induced by PPI in PS. Confocal laser scanning microscopy confirmed that PPI envelopment of starch granules restricted their gelatinization by limiting granule swelling. These results carry significant implications for crafting pea-based foods with desired texture.

Insights into impact of chlorogenic acid on multi-scale structure and digestive properties of lotus seed starch under autoclaving treatment

The interaction between polyphenols and starch is an important factor affecting the structure and function of starch. Here, the impact of chlorogenic acid on the multi-scale structure and digestive properties of lotus seed starch under autoclaving treatment were evaluated in this study. The results showed that lotus seed starch granules were destroyed under autoclaving treatment, and chlorogenic acid promoted the formation of loose gel structure of lotus seed starch. In particular, the long- and short-range ordered structure of lotus seed starch-chlorogenic acid complexes were reduced compared with lotus seed starch under autoclaving treatment. The relative crystallinity of A-LS-CA complexes decreased from 23.4 % to 20.3 %, the value of R1047/1022 reduced from 0.87 to 0.80, and the proportion of amorphous region increased from 10.26 % to 13.85 %. In addition, thermal stability, storage modulus and loss modulus of lotus seed starch-chlorogenic acid complexes were reduced, indicating that the viscoelasticity of lotus seed starch gel was weakened with the addition of chlorogenic acid. It is remarkable that chlorogenic acid increased the proportion of resistant starch from 58.25 ± 1.43 % to 63.85 ± 0.96 % compared with lotus seed starch under autoclaving treatment. Here, the research results provided a theoretical guidance for the development of functional foods containing lotus seed starch.

Role of pea protein isolate in modulating pea starch digestibility: insights from physicochemical and microstructural analysis

BACKGROUND

Understanding the interactions between protein and starch is crucial in revealing the mechanisms by which protein influences starch digestibility. The present study investigated the impact of different contents of pea protein isolate (PPI) on the physicochemical properties and digestibility of pea starch (PS).

RESULTS

The results demonstrated that as the content of PPI increased from 0% to 12%, and the digestion of PS decreased by 12.3%. Rheological analysis indicated that PPI primarily interacted with molecular chains of PS through hydrogen bonds. Increasing the content of PPI resulted in a 30.6% decrease in the hardness of the composite gels, accompanied by a 10% reduction in the short-ordered structure of PS. This hindered the formation of molecular aggregation and resulted in a loose and disordered gel network structure. The microstructure confirmed that the attachment of PPI to PS served as a physical barrier, impeding starch digestibility.

CONCLUSION

In summary, the primary mechanism by which PPI inhibited PS digestion involved steric hindrance exerted by PPI and its interaction with PS via hydrogen bonds. These findings contribute to a better understanding of the interaction mechanisms between PS and PPI and offer insights for the optimal utilization of pea resources. © 2024 Society of Chemical Industry.

Fabrication, Functional Properties, and Potential Applications of Mixed Gellan-Polysaccharide Systems: A Review

Gellan, an anionic heteropolysaccharide synthesized by Sphingomonas elodea, is an excellent gelling agent. However, its poor mechanical strength and high gelling temperature limit its application. Recent studies have reported that combining gellan with other polysaccharides achieves desirable properties for food- and biomaterial-related applications. This review summarizes the fabrication methods, functional properties, and potential applications of gellan-polysaccharide systems. Starch, pectin, xanthan gum, and konjac glucomannan are the most widely used polysaccharides in these composite systems. Heating-cooling and ionic-induced cross-linking approaches have been used in the fabrication of these systems. Composite gels fabricated using gellan and various polysaccharides exhibit different functional properties, possibly because of their distinct molecular interactions. In terms of applications, mixed gellan-polysaccharide systems have been extensively used in texture modification, edible coatings and films, bioactive component delivery, and tissue-engineering applications. Further scientific studies, including structural determinations of mixed systems, optimization of processing methods, and expansion of applications in food-related fields, are needed.

Changes in the pasting and rheological properties of wheat, corn, water caltrop and lotus rhizome starches by the addition of Annona montana mucilage

Annona montana mucilage (AMM) is a novel mucilage with unique but limited information. This study investigated the effects of AMM addition on the pasting and rheological properties of wheat starch (WS), corn starch (CS), water caltrop starch (WCS), and lotus rhizome starch (LRS). The addition of AMM generally increased the pasting temperature and peak viscosity, but reduced the setback value of all starches to varying degrees, and the initiation of viscosity-increase for cereal starch/AMM systems during pasting occurred at lower temperatures, accompanied with a distinctive two-stage swelling process as well as lower peak and final hot paste viscosity at 50 °C. AMM significantly increased the pseudoplasticity and entanglement of the systems to varying degrees (LRS > WS > WCS > CS). Under a constant shear rate of 50 s-1, the consistency level was found to fall in honey-like for cereal starch/AMM groups, and honey-like to extremely thick levels for WCS and LRS/AMM groups. Except for the WCS/AMM systems, the storage and loss modulus as well as tan increased with increasing AMM concentration. Short-term retrogradation of starch at 4 °C was pronouncedly retarded by the addition of AMM for WS, CS and WCS groups, but was less affected for LRS group.

Effects of Laminaria japonica polysaccharide and coumaric acid on pasting, rheological, retrogradation and structural properties of corn starch

The aim of this study was to investigate the effects of Laminaria japonica polysaccharide (LJP) and coumaric acid (CA) on pasting, rheological, retrogradation and structural properties of corn starch (CS). Rapid viscosity analysis (RVA) revealed that LJP significantly increased the peak viscosity, trough viscosity, final viscosity, and setback viscosity of CS gel (p < 0.05) in a concentration-dependent manner. The addition of LJP and CA simultaneously caused the pasting of CS to need a greater temperature (from 75.53 °C to 78.75 °C), suggesting that LJP and CA made CS pasting more difficult. Dynamic viscoelasticity measurements found that all gels exhibited typical characteristics of weak gel. When compared to CS gel, 4 % LJP increased the viscosity and fluidity of gel and the simultaneous addition of LJP and CA reduced the elasticity. The steady shear results showed that the all gels were pseudoplastic fluids with shear-thinning behavior. In the meanwhile, the addition of LJP and CA enhanced the pseudoplasticity of CS-LJP-CA gel and improved its shear thinning. Furthermore, thermodynamic results showed that 8 % LJP promoted the retrogradation of CS gel and 2.0 % CA delayed the retrogradation of CS gel. Notably, on the 7th day of retrogradation, 2.0 % CA significantly decreased the retrogradation rate of CS-LJP by 19.31 % as compared to CS + 8 % LJP. Microstructure observation revealed that LJP made the honeycomb network structure of CS gel partially collapsed, and the surface of CS-LJP gel developed venation. Nevertheless, the structure of CS-LJP gel was clearly enhanced by adding CA. FT-IR spectra demonstrated that the addition of LJP or CA to CS did not result in the formation of a new distinctive peak in the system, suggesting the absence of a new group. Moreover, LF-NMR findings showed that LJP and CA strengthened the gel structure of CS and enhanced its capacity to retain water. This study not only provided a new insight into using LJP and CA to regulate the gel properties of CS, but also provided scientific strategy for developing starchy foods.

New insights into the interaction between bamboo shoot polysaccharides and lotus root starch during gelatinization, retrogradation, and digestion of starch

In this study, the interaction between bamboo shoot polysaccharides (BSP) and lotus root starch (LS) during gelatinization, retrogradation, and digestion of starch was investigated. The addition of BSP inhibited the gelatinization of LS and decreased the peak viscosity, valley viscosity, and final viscosity. Amylose leaching initially increased and then decreased with the increase in BSP addition. The apparent viscosity and viscoelasticity of LS decreased with the increase in BSP addition. Moreover, 3 % BSP increased the hardness and cohesiveness of LS gel, whereas 6 %-15 % BSP decreased them. In addition, 3 %-6 % BSP promoted the uniform distribution of water molecules in the starch paste, whereas the addition of 12 % and 15 % BSP resulted in the inhomogeneous distribution of the water. The retrogradation degree of LS gel gradually increased with the increase in BSP addition from 3 % to 6 %, whereas 9 %-15 % BSP restricted the short-term and long-term retrogradation of LS. After 12 % BSP was added, the RDS content reduced by 11.6 %, the RS content significantly increased by 75 %, and the digestibility of starch decreased. This work revealed the interaction between BSP and LS during starch gelatinization, retrogradation, and digestion to improve the physicochemical properties and digestive characteristics of LS.

Influence of roasted flaxseed marc flour on rheological, structural, fermentation, water distribution, and migration properties of wheat dough

Roasted flaxseed (RF) marc, which is a by-product obtained from RF oil extraction, has high nutritional value. This study evaluated the impact of RF marc flour on rheological, structural, fermentation, water distribution, and migration properties of the wheat dough. Results showed that adding RF into wheat flour (WF) could effectively increase the water absorption in the dough and retard the retrogradation of starch. The fermentation results revealed that adding RF could improve the gas retention coefficient of dough. Compared to the dough prepared with WF, the doughs enriched with RF had higher tan δ values (ratio of loss modulus G″ to storage modulus G'), indicating a more liquid-like property. The mobility of tightly bound and free water in dough was decreased by adding RF, whereas the distribution of free water was increased. On the one hand, adding RF would dilute the gluten content in dough, resulting in a weaker protein network. On the other hand, the dietary fiber and proteins in RF could offset the gluten dilution effect to some extent. Overall, the results suggested that the substitution level of RF in WF should be below 25% to avoid serious dough quality deterioration, and the RF-WF blended flour could be a potential ingredient to produce wheat products with moist taste. These findings could be useful for guiding the future usage of RF marc in wheat-based products.

Complexation of starch and phenolic compounds during food processing and impacts on the release of phenolic compounds

Phenolic compounds can form complexes with starch during food processing, which can modulate the release of phenolic compounds in the gastrointestinal tract and regulate the bioaccessibility of phenolic compounds. The starch-phenolic complexation is determined by the structure of starch, phenolic compounds, and the food processing conditions. In this review, the complexation between starch and phenolic compounds during (hydro)thermal and nonthermal processing is reviewed. A hypothesis on the complexation kinetics is developed to elucidate the mechanism of complexation between starch and phenolic compounds considering the reaction time and the processing conditions. The subsequent effects of complexation on the physicochemical properties of starch, including gelatinization, retrogradation, and digestion, are critically articulated. Further, the release of phenolic substances and the bioaccessibility of different types of starch-phenolics complexes are discussed. The review emphasizes that the processing-induced structural changes of starch are the major determinant modulating the extent and manner of complexation with phenolic compounds. The controlled release of complexes formed between phenolic compounds and starch in the digestive tracts can modify the functionality of starch-based foods and, thus, can be used for both the modulation of glycemic response and the targeted delivery of phenolic compounds.

Structural, Thermal and Pasting Properties of Heat-Treated Lotus Seed Starch–Protein Mixtures

The interactions between starch and protein, the essential components of lotus seed, strongly influence the quality of lotus seed processing by-products. This study investigated the effects of lotus seed starch–protein (LS-LP) interactions on the structural, thermal and gelatinization properties of LS-LP mixtures, using LS/LP ratios of 6:1, 6:2, 6:3, 6:4, 6:5, or 1:1, after heat treatment (95 °C, 30 min). Fourier transform infrared peaks at 1540 cm⁻¹ and 3000–3600 cm⁻¹ revealed the major interactions (electrostatic and hydrogen bonding) between LS and LP. The UV–visible absorption intensities (200–240 nm) of LS-LP mixtures increased with increased protein content. X-ray diffraction and electron microscopy revealed that LS-LP consists of crystalline starch granules encapsulated by protein aggregates. Increasing the addition of protein to the mixtures restricted the swelling of the starch granules, based on their solubility, swelling properties and thermal properties. Viscometric analysis indicated that the formation of LS-LP mixtures improved structural and storage stability. These findings provide a practicable way to control the thermal and gelatinization properties of lotus seed starch–protein mixtures, by changing the proportions of the two components, and provide a theoretical basis for developing novel and functional lotus-seed-based foods.

Dietary compounds slow starch enzymatic digestion: A review

Dietary compounds significantly affected starch enzymatic digestion. However, effects of dietary compounds on starch digestion and their underlying mechanisms have been not systematically discussed yet. This review summarized the effects of dietary compounds including cell walls, proteins, lipids, non-starchy polysaccharides, and polyphenols on starch enzymatic digestion. Cell walls, proteins, and non-starchy polysaccharides restricted starch disruption during hydrothermal treatment and the retained ordered structures limited enzymatic binding. Moreover, they encapsulated starch granules and formed physical barriers for enzyme accessibility. Proteins, non-starchy polysaccharides along with lipids and polyphenols interacted with starch and formed ordered assemblies. Furthermore, non-starchy polysaccharides and polyphenols showed robust abilities to reduce activities of α-amylase and α-glucosidase. Accordingly, it can be concluded that dietary compounds lowered starch digestion mainly by three modes: (i) prevented ordered structures from disruption and formed ordered assemblies chaperoned with these dietary compounds; (ii) formed physical barriers and prevented enzymes from accessing/binding to starch; (iii) reduced enzymes activities. Dietary compounds showed great potentials in lowering starch enzymatic digestion, thereby modulating postprandial glucose response to food and preventing or treating type II diabetes disease.

Structure and physicochemical properties of cross-linked and acetylated tapioca starches affected by oil modification

This work investigated the structure and physicochemical properties of cross-linked tapioca starch (CTS), acetylated tapioca starch (ATS) and their counterparts (Oil-CTS and Oil-ATS). The results showed oil on the interface of starch granules promoted granule agglomeration after oil modification. Besides, oil modification could increase granule size and destroy the crystalline structure but did not affect the molecular structure of starch. Meanwhile, oil-modified starches did not form the V-type structure like amylose-fatty acid complex, suggesting that oil could not enter the helical cavity of amylose to form complex. Furthermore, compared with CTS and ATS, oil-modified starches had higher shear resistance, lower viscosity and gelatinization enthalpy. Notably, Oil-CTS possessed excellent emulsion stability, with the potential application as an emulsion stabilizer. This study revealed oil modification as an innovative method to endow starch with high shear resistance, low gelatinization enthalpy and excellent emulsion stability to meet the demands of food industries.

Research of the influence of xanthan gum on rheological properties of dough and quality of bread made from sprouted wheat grain

The effect of microbial polysaccharide xanthan in the amount of 0.1-0.4% on the rheological characteristics of the dough from sprouted wheat grain and quality indicators of bread was studied. It was found that when xanthan gum is added, the dough's spreading and adhesion strength decreases, and the dough's resilience-elastic and plastic-viscous characteristics improve. Bread made from sprouted wheat grains with the addition of experimental dosages of xanthan has better structural-mechanical and physicochemical properties, as evidenced by higher indicators of crumb compressibility, specific volume, and moisture compared to the control sample. To obtain bread with the best quality indicators, it is recommended to use 0.3% xanthan.

Structure-digestibility relationships in the effect of fucoidan on A- and B-wheat starch

Fucoidans (FC) have a variety of biological activities, and it can also affect the functionality and nutritional characteristics of starch-based food products. However, there are few studies on the structural and digestive properties of starch - fucoidans blends. The effect of FC at different concentrations (0, 0.6 %, 0.8 %, 1.0 %, w/v) on the structural properties and digestibility properties of A-type wheat starch (AS) and B-type wheat starch (BS) subjected to autoclave treatment were investigated. The results show that compared with native wheat starch, AS with FC displayed higher crystallinity as well as the structural ordering, but the crystallinity and degree of order of BS with FC decreased, which was proposed due to AS interact with FC in crystalline region but BS reacts with FC in the amorphous region. With the interaction of FC with AS and BS, granules compactness of AS and BS were enhanced. The addition of FC delayed digestion in vitro of AS and BS, the rapidly digestible starch content was obviously lower than native one, and the proportion of slowly digestible starch raise markedly. This study might broaden the recognition of wheat starch with different proportion of AS and BS, and provide a theoretical basis for the potential utilization of FC in carbohydrate based food industry.

Insights into the formation and digestive properties of lotus seed starch-glycerin monostearate complexes formed by freeze-thaw pretreatment and microfluidization

The objective of this paper was to investigate the formation and digestive properties of lotus seed starch-glycerin monostearate complexes (LSG) formed by freeze-thaw pretreatment and microfluidization. The results showed that the preparation of LSG with six freeze-thaw cycles at 60 MPa had the highest complex index (69.92%). The formation of LSG led to the conversion of the crystalline pattern of lotus seed starch from C-type to V-type and increased the proportion of the microcrystalline region. In addition, the digestive results indicated that LSG had a high resistance to digestive enzymes, which was conducive to increasing the content of resistant starch. Based on the above investigation, the formation and digestive properties showed that the appropriate number of freeze-thaw cycles of pretreatment could facilitate the complexation of starch and lipid under low-pressure microfluidization, which made for the directional regulation of helical conformation and anti-digestion.

Properties and digestibility of a novel porous starch from lotus seed prepared via synergistic enzymatic treatment

The objective was to investigate the effect of synergistic enzymatic treatment on the properties and digestibility of a novel C-type lotus seed porous starch (LPS). Scanning electron microscopy showed that the densest and most complete pores were formed on the surface of LPS when the concentration of enzymes added was 1.5% (LS-1.5E). With increases in enzyme addition, the oil and water absorption of the porous starch increased and reached maxima at 1.5% of enzyme. Increased in the specific surface area, total pore volume and average pore diameter of LPS were determined by low-temperature nitrogen adsorption, while when the enzymes exceeded 1.5%, there were no significant changes. Compared to lotus seed starch (LS), the particle size of LPS also decreased. With the increases in enzyme addition, LPS exhibited higher relative crystallinity and ordering structure by XRD and FTIR. The results by SAXS confirmed that LPS had higher ordered semi-crystalline lamellar and denser lamellar structure compared to LS. Low-field ¹H NMR spectroscopy indicated that the proportion of bound water in LPS increased, while the proportion of bulk water decreased. Moreover, the degree of hydrolysis of LPS was lower than that of LS, and the content of rapidly digestible starch decreased, while the content of slowly digestible starch and resistant starch increased with the enzyme addition, which was consistent with the structural properties.

Modifying the rheological properties, in vitro digestion, and structure of rice starch by extrusion assisted addition with bamboo shoot dietary fiber

This paper investigated the effect of extrusion treatment on the rheological properties, in vitro digestibility, and multi-structure of starch with or without bamboo shoot dietary fiber (BSDF). The viscoelasticity and thixotropy decreased after extrusion treatment, however, they increased after BSDF addition, and decreased with increasing BSDF content. The starch granules became smooth and formed big lumps after extrusion treatment. The dense lumps became loose after the addition of BSDF. Extrusion treatment changed the movement and arrangement of starch chains and thus the relative crystallinity and branching degree decreased by 92.6% and 40.9%, respectively. The disruption of starch further increased rapid digestion starch (RDS) content by 10%. The decreased disruption of starch granules and increased entanglement between BSDF and starch decreased the RDS content. The addition of BSDF is a novelty method to enhance the nutritional properties and control the physicochemical properties of extruded starchy foods.

Effects of Auricularia auricula-judae polysaccharide on pasting, gelatinization, rheology, structural properties and in vitro digestibility of kidney bean starch

Auricularia auricula-judae polysaccharide (AP) has unique molecular structures and multiple bioactivities with excellent gel-forming property and thermal tolerance. However, few researches focus on the interactions between AP and legume starches. In this study, the effects of AP on the pasting, gelatinization, rheology, microstructure, and in vitro digestibility of kidney bean starch (KBST) were evaluated. The pasting, gelling and structural properties of AP-KBST mixtures were characterized by rapid visco analyzer, rheometry, texture analyzer, laser particle analyzer, low-field nuclear magnetic resonance, Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. And an in vitro method was employed to measure the digestibility of AP-KBST composites. The pasting viscosity, swelling degree of starch granules, viscoelasticity, gel strength, cold storage stability and water-retention capacity of KBST were enhanced with increasing AP concentration. The combination of AP and KBST exhibited a higher short-range ordered and a firmer and denser structure than that of KBST alone. Moreover, AP increased the contents of resistant starch and slowly digestible starch, which were positively correlated with the storage modulus and the degree of order, thereby suggesting that the formation of strong and ordered gel network structure by synergistic interactions between AP and KBST was responsible for the reduced starch digestibility.

Effects of freeze-thaw pretreatment on the structural properties and digestibility of lotus seed starch-glycerin monostearin complexes

To investigate the effects of freeze-thaw cycle pretreatment (in one cycle, frozen samples were reheated to 50 °C and then frozen at -20 °C) on the structural properties and digestibility of lotus seed starch-glycerin monostearin complexes, their complex index, crystal structure, molecular structure, micro-morphology, and digestibility were analyzed. The results showed that an appropriate number of freeze-thaw cycles facilitated the helical assembly of lotus seed starch and glycerin monostearin. Specifically, six cycles of freeze-thaw pretreatment were favorable for forming V_6I-type complexes with high microcrystalline proportion. This contributed to the high stability of crystalline region and order arrangement of molecular structure. Moreover, V_6I-complexes were in the form of lamellar debris in micro-morphology, and their total digestion and digestion rates were lower than those of other samples. These results were of significance for developing slowly digesting lotus seed starch-based food.

The impact of various exogenous type starch on the structural properties and dispersion stability of autoclaved lotus seed starch

In order to investigate the effects of exogenous V-type starch on the structural properties and dispersion stability of lotus seed starch after autoclave treatment, the crystal structure, molecular structure, and dispersion stability were analyzed and discussed, as well as compared with exogenous A-type and B-type starches. Analysis of structural properties indicated that the addition of different crystal nuclei led the crystallization of disordered helices to a specific direction. The B- and V-type starch addition increased the crystallinities of starch and enhanced the ordered arrangement of disordered helices, whereas A-type starch had no significant positive influence on the stability of starch system. The microstructure observation showed that A- and B-type starch addition led to a rough and porous morphology of starch particles; the presence of V-type starch retarded the agglomeration and retrogradation of starch after autoclaving. Analysis of contact angle and dispersion stability revealed that the addition of various exogenous starch increased the contact angle of starch particles in different extent, suggesting the enhancement of hydrophobicity. But B-type starch addition resulted in the poor dispersion stability compared to A-type starch, instead V-type starch addition improved the dispersion stability of starch in aqueous solution, allowing the particles to stay dispersed for 141.12 ± 6.52 min. These results provided a theoretical basis for the effects of exogenous type starch on original starch properties, and revealed the potential of V-type starch as dispersion stabilizer.

Effect of Mesona chinensis polysaccharide on the pasting, rheological, and structural properties of tapioca starch varying in gelatinization temperatures

The effects of Mesona chinensis polysaccharide (MCP) on the pasting, rheological properties, granule size, and water mobility of tapioca starch (TS) were investigated at different gelatinization temperatures (75 °C and 95 °C). The structures of tapioca starch-Mesona chinensis polysaccharide (TM) gels formed at different gelatinization temperatures were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the peak, trough, and final viscosities of TM-95 mixtures were lower than that of TM-75 mixtures. Addition of MCP had a significant reduce (p < 0.05) on the granule size and transversal relaxation time of TM mixtures at the two gelatinization temperatures. Rheological analysis also showed that the addition of MCP increased the consistency indexes (K) and decreased the flow behavior indexes (n) of TM-95 and TM-75 gels. XRD results confirmed the diffraction peak of TM-95 gels became blunt and wider, and the diffraction peak at 17° and 23° of TM-75 gels could be observed after MCP added. In addition, the microstructures of TM-75 gels were more compact than that of TM-95 gels. These results can promote the development of TS-based products and application of MCP at different gelatinization temperatures.

Rheological Properties of Wheat-Flaxseed Composite Flours Assessed by Mixolab and Their Relation to Quality Features

The effect of adding brown and golden flaxseed variety flours (5%, 10%, 15% and 20% w/w) to wheat flours of different quality for bread-making on Mixolab dough rheological properties and bread quality was studied. The flaxseed-wheat composite flour parameters determined such as fat, protein (PR), ash and carbohydrates (CHS) increased by increasing the level of flaxseed whereas the moisture content (MC) decreased. The Falling Number values (FN) determined for the wheat-flaxseed composite flours increased by increasing the level of flaxseed. Within Mixolab data, greater differences were attributed to the eight parameters analysed: water absorption, dough development time, dough stability and all Mixolab torques during the heating and cooling stages. Also, a general decreased was also recorded for the differences between Mixolab torques which measures the starching speed (C3-2), the enzymatic degradation speed (C4-3) and the starch retrogradation rate (C5-4), whereas the difference which measures the speed of protein weakening due to heat (C1-2) increased. Composite dough behaviour presented a close positive relationship between MC and DT, and FN and PR with the C1-2 at a level of p < 0.05. The bread physical and sensory quality was improved up to a level of 10-15% flaxseed flour addition in wheat flour.