Effects of oligomeric procyanidins on the retrogradation properties of maize starch with different amylose/amylopectin ratios

Rheological properties, multiscale structure, and in vitro digestibility of a maize starch-konjac glucomannan-bamboo leaf flavonoid complex modified by dynamic high-pressure microfluidization

The effects of dynamic high-pressure microfluidization (DHPM) treatment on the rheological properties, multiscale structure and in vitro digestibility of complex of maize starch (MS), konjac glucomannan (KGM), and bamboo leaf flavonoids (BLFs) were investigated. Compared with MS, the MS-KGM-BLF complex exhibited reduced viscosity and crystallinity, along with increased lamellar thickness to 10.26 nm. MS-KGM-BLF complex had lower viscosity after DHPM treatment. The highest ordered structure and crystallinity were observed at 50 MPa, with the α value increasing from 3.40 to 3.59 and the d value decreasing from 10.26 to 9.81 nm. However, higher DHPM pressures resulted in a decrease in the α value and an increase in the d value. The highest gelatinization enthalpy and resistant starch content were achieved at 100 MPa DHPM, while the fractal structure shifted from surface fractal to mass fractal at 150 MPa. This study presents an innovative method for enhancing the properties of MS.

Structural characterization and physicochemical properties of grain amaranth starch

With potato starch (PS) and corn starch (CS) as the controls, the structure and physicochemical properties of grain amaranth starch (GAS) and its binding with dihydromyricetin were investigated in this study. The results indicated that GAS granules were small in size (3.21 ± 0.13 μm) and had a low amylose content (11.57 ± 0.91%). GAS exhibited low paste clarity, solubility, and swelling power, but demonstrated good freeze-thaw stability and resistance to retrogradation. Although the pasting temperature of GAS was high (75.88 ± 0.03 °C), its peak viscosity, breakdown viscosity, and setback viscosity were significantly lower than those of PS and CS. GAS was classified as A-type starch, with a high molecular weight and broad distribution (Mw, 3.96 × 107 g/mol; PDI, 2.67). For its chain length distribution, chain B1 had the highest proportion (50.09%), while chain B3 had the lowest proportion (13.50%). The complexation of GAS with dihydromyricetin effectively enhanced its ABTS and DPPH free radical scavenging capacities.

Interaction of anthocyanins, soluble dietary fiber and waxy rice starch: Their effect on freeze-thaw stability, water migration, and pasting, rheological and microstructural properties of starch gels

This study aimed to investigate the effect of the interaction of black rice anthocyanins (BRA), soluble dietary fiber from extruded rice bran (ES) and waxy rice starch (WRS) on the physicochemical properties of starch gels, including gelatinization properties, rheological properties, freeze-thaw stability, water migration, molecular structure and gel microstructure. The results showed that the pasting temperature (PT) of the mixtures was increased, and the peak viscosity (PV), trough viscosity (TV), final viscosity (FV) and setback viscosity (SV) were significantly reduced when ES and BRA were added to WRS in different proportions (ES:BRA, 4:0, 4:0.4, 4:1, 4:2, 8:0, 8:0.8, 8:2, 8:4). Both ES and BRA could enhance the viscosity of WRS gels, and ES exhibited strong ability on improving the strength of gels. The presence of ES and BRA improved the water retaining capacity of WRS gels, but weakened the freeze-thaw stability. ES, BRA and WRS formed non-covalent bonds (hydrogen bonds) through hydrophilic groups during gelatinization, which improved the gel properties. In addition, the steric hindrance formed by ES and BRA inhibited starch retrogradation. These results might contribute to the development of starch-based food formulations with good quality.

Effects of alginate synergized with polyphenol compounds on the retrogradation properties of corn starch

This study aimed to investigate the impact of alginate (AG) on the retrogradation properties of corn starch (CS) in conjunction with three phenolic compounds, including naringin (NA), rutin (RT), and soy isoflavones (SI). The findings indicated that AG, NA, RT, and SI collectively resulted in a significant reduction in the hardness, retrogradation enthalpy, and relaxation time of CS gel. This effect was more pronounced when compared to NA, RT, and SI individually. The findings suggested that the elemental system comprising AG, phenolic compounds, and CS yielded enhanced water retention capacity and thermal stability. Moreover, a noticeable decrease in the short-range ordered structure and crystallinity was observed, indicating that AG and phenolic compounds effectively inhibited the retrogradation of CS; notably, the synergistic interaction between AG and SI resulted in the most favorable outcome. The results of this study provide new ideas for the design, development, and quality improvement of starch-based food.

Persimmon leaf polyphenols as potential ingredients for modulating starch digestibility: Effect of starch-polyphenol interaction

The interaction mode between persimmon leaf polyphenols (PLP) and corn starch with different amylose content and its effect on starch digestibility was studied. Results of iodine binding test, TGA, and DSC revealed that PLP interacted with starch and reduced the iodine binding capacity and thermal stability of starch. High amylopectin corn starch (HAPS) interacted with PLP mainly via hydrogen bonds, since the FT-IR of HAPS-PLP complex showed higher intensity at 3400 cm-1 and an obvious shift of 21 cm-1 to shorter wavelength, and the chemical shifts of protons in 1H NMR and the shift of C-6 peak in 13C NMR of HAPS moved to low field with the addition of PLP. Results of 1H NMR also showed the preferential formation of hydrogen bonds between PLP and OH-3 of HAPS. Different from HAPS, PLP formed V-type inclusion complex with high amylose corn starch (HAS) because XRD of HAS-PLP complex showed characteristic feature peaks of V-type inclusion complex and C-1 signal in 13C NMR of PLP-complexed HAS shifted to low field. Interaction with PLP reduced starch digestibility and HAS-PLP complex resulted in more resistant starch production than HAPS-PLP complex. To complex PLP with starch might be a potential way to prepare functional starch with slower digestion.

Partitioning and in vitro bioaccessibility of apple polyphenols during mechanical and physiological extraction: A hierarchical clustering analysis with LC-ESI-QTOF-MS/MS

Polyphenol partitioning during mechanical (cold-pressing) and physiological (digestion) extraction at the individual polyphenol and subclass level was investigated. UHPLC-ESI-QTOF-MS/MS analysis yielded a comprehensive identification of 45 polyphenols whose semi-quantification revealed a hierarchical clustering strongly determined by polyphenol structure and their location within the apple tissue. For instance, pomace retained most flavonols and flavanols (degree of polymerization DP 5-7), which were highly hydrophobic, hydroxylated, or large (>434 Da), and more abundant in peel. In vitro digestion UHPLC-ESI-QTOF-MS/MS analysis of whole apple (and its corresponding matrix-free extract) clustered polyphenols into five main groups according to their interaction with plant cell walls (PCWs) during each digestion phase. This grouping was not reproduced in pomace, which exhibited a greater matrix effect than whole apple during oral and gastric digestion. Nevertheless, the interaction between most polyphenol groups, including dihydrochalcones, flavanols (DP 1-4) and hydroxycinnamic acid derivatives, and pomace PCWs was lost during intestinal digestion.

Formation and Application of Starch-Polyphenol Complexes: Influencing Factors and Rapid Screening Based on Chemometrics

Understanding the nuanced interplay between plant polyphenols and starch could have significant implications. For example, it could lead to the development of tailor-made starches for specific applications, from bakinag and brewing to pharmaceuticals and bioplastics. In addition, this knowledge could contribute to the formulation of functional foods with lower glycemic indexes or improved nutrient delivery. Variations in the complexes can be attributed to differences in molecular weight, structure, and even the content of the polyphenols. In addition, the unique structural characteristics of starches, such as amylose/amylopectin ratio and crystalline density, also contribute to the observed effects. Processing conditions and methods will always alter the formation of complexes. As the type of starch/polyphenol can have a significant impact on the formation of the complex, the selection of suitable botanical sources of starch/polyphenols has become a focus. Spectroscopy coupled with chemometrics is a convenient and accurate method for rapidly identifying starches/polyphenols and screening for the desired botanical source. Understanding these relationships is crucial for optimizing starch-based systems in various applications, from food technology to pharmaceutical formulations.

The Effects of Tremella fuciformis Polysaccharide on the Physicochemical, Multiscale Structure and Digestive Properties of Cyperus esculentus Starch

In this study, we have investigated the effects of Tremella fuciformis polysaccharide (TP) on the pasting, rheological, structural and in vitro digestive properties of Cyperus esculentus starch (CS). The results showed that the addition of TP significantly changed the pasting characteristics of CS, increased the pasting temperature and pasting viscosity, inhibited pasting, reduced the exudation of straight-chain starch and was positively correlated with the amount of TP added. The addition of the appropriate amount of TP could increase its apparent viscosity and enhance its viscoelasticity. The composite system of CS/TP exhibited higher short-range ordered structure and solid dense structure, which protected the crystal structure of CS, but was related to the amount of TP added. In addition, the introduction of TP not only decreased the in vitro digestion rate of CS and increased the content of slow-digestible starch (SDS) and resistant starch (RS), but also reduced the degree of digestion. Correlation studies established that TP could improve the viscoelasticity, relative crystallinity and short-range order of the CS/TP composite gel, maintain the integrity of the starch granule and crystalline structure, reduce the degree of starch pasting and strengthen the gel network structure of CS, which could help to lower the digestibility of CS.

Enhancing physicochemical, rheological properties, and in vitro rumen fermentation of starch with Melastoma candidum D. Don fruit extract

The utilization of polyphenol-modified starch in ruminants has not undergone extensive exploration. This study aimed to investigate the impact of the complex formed between starch and Melastoma candidum D. Don fruit extract on physicochemical properties, phenol release kinetics in various buffers simulating the gastrointestinal tract, methane production, and post-rumen digestibility. The interaction between starch and M. candidum D. Don fruit extract significantly (p < 0.001) increased resistant starch and particle size diameter. The maximum phenolic release from complex between starch and M. candidum D. Don fruit extract, due to gastrointestinal tract-simulated buffers, ranged from 22.96 to 34.60 mg/100 mg tannic acid equivalent. However, rumen and abomasum-simulated buffers released more phenolic content, whereas the intestine-simulated buffer showed higher antioxidant activity (ferric ion-reducing antioxidant power). Furthermore, complex between starch and M. candidum D. Don fruit extract significantly decreased dry matter rumen digestibility (p < 0.001) and maximum methane gas production (p < 0.001).

The interaction and physicochemical properties of the starch-polyphenol complex: Polymeric proanthocyanidins and maize starch with different amylose/amylopectin ratios

This study investigated the impact of polymeric proanthocyanidins (PPC) on the physicochemical characteristics of maize starch with varying amylose content, and their potential interaction mechanism. PPC with a lower content (1 %) reduced the viscoelasticity of the high amylose maize starch (HAM) system, inhibited amylose rearrangement, and enhanced its fluidity. However, excessive PPC restrained the interaction between PPC and amylose. In contrast to HAM, PPC improved the gelation ability of waxy maize starch (WAM) as PPC concentration was raised. PPC suppressed the recrystallization of starch during storage, and PPC had a superior inhibition influence on the retrogradation of WAM in comparison to HAM. This indicated that amylopectin was more likely to interact with PPC than amylose. Hydrogen bonds were the main driving force between PPC and starch chains, which was clarified by Fourier transform-infrared, nuclear magnetic resonance, X-ray diffraction, iodine bonding reaction, and dynamic light scattering data. Additionally, the mechanism of interaction between PPC and the two starch components may be similar, and variance in physicochemical attributes can be primarily credited to the percentage of amylose to amylopectin in starch.

Study on physicochemical properties and anti-aging mechanism of wheat starch by anionic polysaccharides

The anti-aging effects of two anionic polysaccharides AG (sodium alginate)/SSPS (soluble soybean polysaccharide) and WS (wheat starch) were evaluated, and their different mechanisms were explored. The rheological properties, gelatinization properties and aging properties were characterized. The addition of AG and SSPS changed the gelatinization parameters of WS, decreased the peak viscosity, breakdown viscosity and setback viscosity, and enhanced the fluidity of the gel system. Additionally, the starch molecular orderliness experiment showed that the relative crystallinity of starch gels decreased with the increase in AG and SSPS concentrations, indicating that the rearrangement of amylopectin was disturbed, which inhibited the cross-linking of starch molecules. The water state analysis showed that the hydrophilicity of AG and SSPS and their interactions with starch molecules influenced the relaxation behavior of water protons in the gel system in a concentration-dependent manner. In conclusion, the addition of AG and SSPS could significantly inhibit the aging of WS gels, probably due to the competition effect of AG and SSPS on water and the interaction with starch molecules. The present study results would provide new theoretical insights into WS-based food research.

Structural and Physicochemical Properties of a Chinese Yam Starch-Tea Polyphenol Complex Prepared Using Autoclave-Assisted Pullulanase Treatment

Interactions between food components have a positive impact in the field of food science. In this study, the effects of tea polyphenol on the structural and physicochemical properties of Chinese yam starch using autoclave-assisted pullulanase treatment were investigated. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, rapid visco analysis, differential scanning calorimetry, and the 3,5-dinitrosalicylic acid method were applied in this study. The results showed that the Chinese yam starch-tea polyphenol complex formed a structural domain with higher thermal stability along with lower pasting viscosities than native starch. The in vitro digestibility of Chinese yam starch decreased with the addition of the tea polyphenol, and the amount of resistant starch content in the complex was 56.25 ± 1.37%, significantly higher than that of native starch (p < 0.05). In addition, the complex showed a B+V-type crystalline structure, which confirmed that the interaction modes between the starch and tea polyphenol include hydrogen bonding and hydrophobic interactions. Moreover, the appearance of an irregular sponge network structure of the complex further supported the interactions between the starch and tea polyphenol. This study provides a theoretical basis for the development of functional foods using Chinese yam starch.

Effect of purple red rice bran anthocyanins on pasting, rheological and gelling properties of rice starch

Purple red rice bran (PRRBA), a by-product of the rice polishing process, is frequently thrown away, resulting in a waste of resources. This study investigated the effects of PRRBA on the pasting, rheological property, chemical structure, microstructure, and water migration of rice starch. The results demonstrated that the peak viscosity (PV), final viscosity (FV), and activation energy (retrogradation energy) of rice starch were all decreased by a dose of PRRBA. Furthermore, the gel strength and hardness of rice starch were positively correlated with the addition of PRRBA. Rice starchs particle size distribution can be improved by PRRBA, which may be a result of the non-covalent bonds that exist between PRRBA and rice starch. The addition of PRRBA resulted in a decrease in the spin relaxation time (T2) of rice starch, from 259.7 to 143.6 ms. This can be attributed to that PRRBA improved the water-holding capacity of rice starch. These results could contribute to the development of high-value-added products of PRRBA and facilitate the application of anthocyanins in starch-based foods.

Effect of hydroxypropyl distarch phosphate on the retrogradation properties of sterilized pea starch jelly and its possible mechanism

Due to the high content of amylose in pea starch (PS), PS jelly is prone to retrogradation during storage and its quality reduces subsequently. Hydroxypropyl distarch phosphate (HPDSP) shows a potential inhibitory effect on the retrogradation of starch gel. Based on this, five retrograded PS-HPDSP blends containing 1 %, 2 %, 3 %, 4 % and 5 % (w/w, based on the weight of PS) of HPDSP were prepared, and their long-range, short-range ordered structure and retrogradation properties, and the possible interaction between PS and HPDSP were investigated. The addition of HPDSP significantly reduced the hardness of PS jelly and maintained its springiness during cold storage, and this effect was enhanced with HPDSP dosage being from 1 % to 4 %. The presence of HPDSP destroyed both short-range ordered structure and long-range ordered structure. Rheological results indicated that all the gelatinized samples were typical non-Newtonian fluids with shear-thinning characteristics and HPDSP increased their viscoelasticity in a dose-dependent manner. In conclusion, HPDSP delays the retrogradation of PS jelly mainly by combining with amylose in PS through hydrogen bonds and steric hindrance.

Effects of biochar coupled with chemical and organic fertilizer application on physicochemical properties and in vitro digestibility of common buckwheat (Fagopyrum esculentum Moench) starch

Common buckwheat starch, a functional ingredient, has wide food and non-food applications. Excessive chemical fertilizer application during grain cultivation decreases quality. This study examined the effects of different combinations of chemical fertilizer, organic fertilizer, and biochar treatment on the physicochemical properties and in vitro digestibility of starch. The amendment of both organic fertilizer and biochar was observed to have a greater impact on the physicochemical properties and in vitro digestibility of common buckwheat starch in comparison to organic fertilizer amendment solely. The combined application of biochar, chemical, and organic nitrogen in an 80:10:10 ratio significantly increased the amylose content, light transmittance, solubility, resistant starch content, and swelling power of the starch. Simultaneously, the application reduced the proportion of amylopectin short chains. Additionally, this combination decreased the size of starch granules, weight-average molecular weight, polydispersity index, relative crystallinity, pasting temperature, and gelatinization enthalpy of the starch compared to the utilization of chemical fertilizer alone. The correlation between physicochemical properties and in vitro digestibility was analyzed. Four principal components were obtained, which accounted for 81.18 % of the total variance. These findings indicated that the combined application of chemical fertilizer, organic fertilizer, and biochar would improve common buckwheat grain quality.

The impact of mulberry leaf extract at three different levels on reducing the glycemic index of white bread

In this study, the influences of mulberry leaf extract (MLE) addition on the physicochemical properties including the specific volume, texture and sensory features of white bread (WB) were evaluated by the sensory analysis technology. A double-blind, randomised, repeat-measure design was used to study the impact of MLE addition on the postprandial blood glucose response as well as the satiety index of WB. Results showed that the addition of MLE showed no significant effects on the physicochemical properties of WB except for the slight changes of color and bitterness. The addition of MLE significantly reduced the total blood glucose rise after ingestion of WB over 120 minutes, and reduced the GI value of WB in a dose-effect relationship. When the concentration of MLE reached 1.5 g per 100 g available carbohydrate, the GI value of WB could be reduced from 77 to 43. This study provides important information in terms of the appropriateness of MLE when added to more complex real food, the dose-dependent relationship could supply a reference for the application of MLE.

Probing molecular interactions of amylose-morin complex and their effect on antioxidant capacity by 2D solid-state NMR spectroscopy

Interaction of polyphenols and starch significantly governed the further applications on polyphenol-starchy foods. Elucidation of inter-molecular interaction is, however, a challenge because conventional characterizations could not detect the change of micro-environment caused by weak interactions. Herein, a facile strategy for molecular detection of amylose-polyphenol interactions was reported using two-dimensional solid-state NMR spectroscopy. Amylose-morin complex was prepared and characterized using ¹H NMR, FT-IR, DSC, XRD and SEM. Significantly, variation of chemical shifts, splitted peaks and peak width, monitored by ¹³C CP/MAS and ¹H NMR spectra, identified the strong inter-molecular interaction and binding sites. Furthermore, correlated signals from ¹H-¹³C HETCOR confirmed the binding sites of interactions. These findings confirmed the interaction was inter-molecular hydrogen bonds, which generated between hydroxy-3,5,7 of morin and hydroxy groups of amylose. Besides, DPPH radical scavenging and reducing power assay indicated inter-molecular hydrogen bonds are not strong enough to interfere antioxidant capacity of morin.

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.

Effects of lactic acid bacteria fermentation on the physicochemical and structural characteristics of starch in blends of glutinous and japonica rice

In this study, the effects of lactic acid bacteria (LAB) fermentation on the physicochemical and structural characteristics of mixed starches in blends of glutinous and japonica rice were investigated. Five starter cultures improved in varying degrees the hydration ability, transparency, and freeze-thaw stability of the mixed starches. Mixed starch I, prepared by fermentation of Lactobacillus acidophilus HSP001, exhibited optimal water-holding capacity, solubility, and swelling power. In comparison, mixed starches V and III involved fermentation of L. acidophilus HSP001 and Latilactobacillus sakei HSP002, using ratios of 2:1 and 1:1 to achieve higher transparency and freeze-thaw stability, respectively. The LAB-fermented, mixed starches exhibited excellent pasting properties due to their high peak viscosities and low setback values. Moreover, the viscoelasticity of mixed starches III-V, prepared by compound fermentation of L. acidophilus HSP001 and L. sakei HSP002 in ratios of 1:1, 1:2, and 2:1, respectively, proved superior to their single strain fermentation counterparts. Meanwhile, LAB fermentation resulted in reduced gelatinization enthalpy, relative crystallinity, and short-range ordered degree. Thus, the effects of five LAB starter cultures on mixed starches were inconsistent, but these results provide a theoretical basis for the application of mixed starches. PRACTICAL APPLICATION: Lactic acid bacteria was used to ferment blends of glutinous and japonica rice. Fermented mixed starch had better hydration, transparency, and freeze-thaw stability. Fermented mixed starch exhibited nice pasting properties and viscoelasticity. LAB fermentation corroded starch granules, leading to the decrease of ΔH. Relative crystallinity and short-range order of fermented mixed starch decreased.

Effect of modification by maltogenic amylase and branching enzyme on the structural and physicochemical properties of sweet potato starch

Sweet potato starch (SPSt) was treated sequentially with the combination of maltogenic amylase (MA) and branching enzyme (BE) (MA → BE) or BE and MA (BE→MA) to modify its structural and physicochemical properties. Following the MA → BE and BE→MA modifications, the degree of branching was increased from 12.02 % to 44.06 %; whereas, the average chain length decreased from 18.02 to 12.32. Fourier-transform infrared spectroscopy and digestive performance analysis indicated that the modifications reduced hydrogen bonds and increased resistant starch in SPSt. Rheological analysis revealed that the storage and loss moduli of the modified samples were lower than those of the control samples, except for starch treated with MA alone. X-ray diffraction measurements suggested that the re-crystallisation peak intensities of the enzyme-modified starches were lower than those of the untreated sample. The retrogradation resistance ability of the analysed samples followed the order: BE→MA-starches > MA → BE-starches > untreated starch. The relationship between the crystallisation rate constant and short branched chains (DP_6-9) was well described by linear regression. This study provides a theoretical foundation for retarding the retrogradation of starch, which can improve food quality and extend the shelf-life of enzymatically modified starchy foods.

Role of phenolic acids with different functional groups in the regulation of starch digestion in simulated dietary intake patterns

This study investigated the effects of phenolic acids with different functional groups (cinnamic acid: CIA, caffeic acid: CA, ferulic acid: FA) on corn starch (CS) digestibility by simulating dietary intake patterns (co-heating and non-co-heating) and their mechanism. Both treatments could reduce the digestibility of CS. Compared to the non-co-heating treatment, the resistant starch content of 10 % CA co-heating samples increased by 8.36 %. The co-heating case led to a decrease in the trough viscosity, peak viscosity, and final viscosity of CS. Phenolic acids reduced the short-range order of CS, which was due to the interaction through hydrogen bonding by co-heating. The contribution was most pronounced for CA which contained more hydroxyl groups on the benzene ring. Quartz Crystal microbalance tests further confirmed that different absorption of phenolic acids to CS was caused by their hydroxyl groups on the benzene ring. These results demonstrated that the functional groups of phenolic acids were a controllable factor in inhibiting starch digestion, and co-heating could be considered a promising method to control starch digestion and an advocating way to ingest phenolic supplements.

Wheat Starch Modified with Ligustrum robustum (Rxob.) Blume Extract and Its Action Mechanism

We investigated the modification of wheat starch with Ligustrum robustum (Rxob.) Blume extract (LRE) and determined the action mechanism. Based on differential scanning calorimetry, LRE decreased the gelatinization enthalpy of wheat starch from 19.14 to 7.15 J/g and changed gelatinization temperatures (including the variation in gelatinization onset temperature, peak temperature and conclusion temperature in different degrees). Moreover, LRE affected the pasting viscosity curve of wheat starch, and changed its rheological parameters (including the decrease in storage modulus and loss modulus, as well as the increase in loss tangent). Based on the analysis of scanning electron microscopy and wide-angle X-ray diffraction, LRE increased the hole size and the roughness of the gel microstructure, and decreased the crystallinity of wheat starch. Meanwhile, the evaluation results of the texture analyzer and the colorimeter showed that LRE could change the quality properties (including decrease hardness, fracturability and L* values, as well as increase a* and b* values) of wheat starch biscuits after hot air baking (170 °C). Furthermore, with molecular dynamics simulation analysis, phenolic compounds of LRE combined with starch molecules via H-bonds and affected the formation of molecular bonds (including intra- and intermolecular hydrogen bonds), so as to change the spatial conformation and properties of wheat starch during gelatinization and retrogradation. The present results suggest that LRE can modify the physicochemical properties of wheat starch and further improve its processing properties, indicating its potential in the design and development of starch foods (such as steamed buns, bread, biscuits, etc.).

Phenolic Release during In Vitro Digestion of Cold and Hot Extruded Noodles Supplemented with Starch and Phenolic Extracts

Dietary phenolic compounds must be released from the food matrix in the gastrointestinal tract to play a bioactive role, the release of which is interfered with by food structure. The release of phenolics (unbound and bound) of cold and hot extruded noodles enriched with phenolics (2.0%) during simulated in vitro gastrointestinal digestion was investigated. Bound phenolic content and X-ray diffraction (XRD) analysis were utilized to characterize the intensity and manner of starch-phenolic complexation during the preparation of extruded noodles. Hot extrusion induced the formation of more complexes, especially the V-type inclusion complexes, with a higher proportion of bound phenolics than cold extrusion, contributing to a more controlled release of phenolics along with slower starch digestion. For instance, during simulated small intestinal digestion, less unbound phenolics (59.4%) were released from hot extruded phenolic-enhanced noodles than from the corresponding cold extruded noodles (68.2%). This is similar to the release behavior of bound phenolics, that cold extruded noodles released more bound phenolics (56.5%) than hot extruded noodles (41.9%). For noodles extruded with rutin, the release of unbound rutin from hot extruded noodles and cold extruded noodles was 63.6% and 79.0%, respectively, in the small intestine phase, and bound rutin was released at a much lower amount from the hot extruded noodles (55.8%) than from the cold extruded noodles (89.7%). Hot extrusion may allow more potential bioaccessible phenolics (such as rutin), further improving the development of starchy foods enriched with controlled phenolics.

Facile preparation of PVA hydrogels with adhesive, self-healing, antimicrobial, and on-demand removable capabilities for rapid hemostasis

Multifunctional and smart hydrogel-based hemostatic materials are of great significance in the field of medical care. In this paper, a facile method for the preparation of self-healing, adhesive and on-demand removable PBO hydrogels was established with a simple mixture of polyvinyl alcohol (PVA), borax and oligomeric procyanidin (OPC). In this hydrogel system, borax and OPC were used as dynamic crosslinkers to connect the PVA macromolecules through reversible borate ester bonds and hydrogen bonds, resulting in hydrogels that possess good self-healing and adhesive abilities. Furthermore, the PBO hydrogel displayed excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus. In addition, thanks to the adhesive property of the hydrogel and the inherent hemostatic activity of OPC, this hydrogel showed rapid hemostasis performance as concluded from the in vivo experiments of mouse liver incision, tail amputation and femoral artery models. Benefitting from the fast degradation in water, this hydrogel could be easily removed on-demand within 10 min. Therefore, this well-designed PBO hydrogel offers an important prospect as a rapid hemostatic dressing.

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.

Retardant effect of different charge-carrying amino acids on the long-term retrogradation of normal corn starch gel

The effects of different charge-carrying amino acids (lysine, aspartic acid, and tyrosine) on the long-term retrogradation properties of normal corn starch (NCS) gel were studied by differential scanning calorimetry, X-ray diffractometry, low-field nuclear magnetic resonance, and dynamic rheological tests. The results suggested that these amino acids could inhibit the long-term retrogradation of NCS gels, among which the positively charge-carrying amino acid (lysine) showed the most significant inhibitory effect and the zero net charged amino acid (tyrosine) exhibited the worst inhibitory effect. These amino acids significantly decreased the retrogradation enthalpy, hardness, and R_1047/1022 value of NCS gels, as well as inhibited the recrystallization of NCS. The results of retrogradation kinetics suggested that the recrystallization of NCS with amino acids followed the instantaneous nucleation and the crystallization rate constant k of recrystallization was reduced by these amino acids. The amino acids could interact with starch molecules to form hydrogen bonds and steric hindrance during the recrystallization process, which prevented the formation of double helix structures, as well as reduced the water diffusion and exudation from NCS. Therefore, the lysine could be used as a good retrogradation inhibitor for starch in food industry.

The Procyanidin C1-Dependent Inhibition of the Hydrolysis of Potato Starch and Corn Starch Induced by Pancreatin

Procyanidins are contained in various foods, and their effects on starch hydrolysis have been reported. In Japan, black soybeans, which contain a trimeric procyanidin, procyanidin C1 (proC1), are cooked with rice and used to prepare dumplings. In this study, the effects of proC1 on the pancreatin-induced formation of reducing sugars and starch hydrolysis were studied using potato starch and corn starch. ProC1 inhibited both reactions; the inhibition was greater in potato starch than corn starch when added to heated potato starch and corn starch. When heated with proC1, its inhibitory effects decreased, especially in potato starch, suggesting the important role of proC1 itself for the inhibition of potato starch hydrolysis. ProC1 also inhibited the hydrolysis when added to heated, longer amylose (average molecular weight: 31,200), and the inhibition decreased when heated with the amylose. On the other hand, proC1 could not inhibit the hydrolysis when added to heated, shorter amylose (average molecular weight: 4500), but could when heated with the amylose, suggesting the important role of the degradation products of proC1 for the inhibition. We discuss the mechanism of the proC1-dependent inhibition of amylose hydrolysis, taking the molecular weight into account.

Effects of proanthocyanidins on the pasting, rheological and retrogradation properties of potato starch

BACKGROUND

Proanthocyanidins (PAS) were complexed with potato starch (PS) to prepare polyphenol-starch complexes. The pasting, rheological and retrogradation properties of the complexes were investigated.

RESULTS

The addition of PAS markedly affected the pasting, rheological and retrogradation properties of PS, especially at a concentration of 5% (w/w). Rapid viscosity analysis indicated that PAS significantly changed the viscosity, breakdown and setback value of PS. The rheological results showed that PAS decreased the flow behavior index and consistency coefficient, but increased the viscoelasticity of PS. Differential scanning calorimetry and X-ray diffraction indicated that PAS delayed the retrogradation of PS. Furthermore, scanning electron microscopy indicated that the morphologies of retrograded PS gels were greatly altered to a less compact structure with the presence of PAS. Moreover, Fourier transform infrared spectroscopy elucidated that PAS interacted with PS via a noncovalent interaction, and inhibited the retrogradation of PS.

CONCLUSIONS

The findings suggested that supplementing PS with PAS might be an effective and convenient method for modifying the physicochemical properties of PS. © 2021 Society of Chemical Industry.

A comprehensive review of the factors influencing the formation of retrograded starch

The retrogradation of starch is an inevitable change that occurs in starchy food during processing and storage, in which gelatinized starch rearranges into an ordered state. The chain length, proportion and structure of amylose and amylopectin vary in different types of starch granules, and the process is affected by the genes and growth environment of plants. The internal factors play a significant role in the formation of retrograded starch, while the external factors have a direct impact on its structural rearrangement, and the creation of suitable conditions enables food components to affect the rearrangement of starch. Interestingly, water not only directly affects the gelatinization and retrogradation of starch, but also serves as a bridge to deliver the influence of other components that influence retrogradation. Moreover, there are three mechanisms responsible for forming retrograded starch: the migration of starch molecular chains in the starch-water mixed system, the redistribution of water molecules, and the recrystallization kinetics of gelatinized starch. In this paper, the effects of internal factors (amylose, amylopectin, food ingredients) and external factors (processing conditions) on the formation of retrograded starch and the mechanism controlling these effects are reviewed.

Influence of sodium alginate on the gelatinization, rheological, and retrogradation properties of rice starch

Adding hydrocolloids into native starch is a secure and effective method of physical modification. In this study, the effect of sodium alginate (AG) on the gelatinization, rheological, and retrogradation properties of rice starch (RS) was investigated by measuring the pasting parameters, melting enthalpy (ΔH), rheological characteristic parameters, intensity ratio of 1047 cm^-1 to 1022 cm^-1 (R_1047/1022), and relative crystallinity (RC) of RS-AG blends. Rapid visco analysis shows that AG could significantly change the gelatinization parameters of RS. Differential scanning calorimetry results show that the ΔH values of RS initially decreased in the low AG concentration range (0.10%-0.30%), but increased in the high AG concentration range (0.30%-0.50%). Dynamic rheological analysis reveals that the modulus (G', G'') and the loss tangent (tan δ) increased with the rise of the AG concentration from 0.10% to 0.50%. Fourier transform infrared spectroscopy and X-ray diffraction patterns collectively prove that the crystallinity of RS decreased with the addition of AG during the retrogradation periods. The interactions between AG and starch molecules in RS-AG blends were hypothesized to correlate with the aforementioned results.

Applications of waxy corn flour based on physicochemical and processing properties: comparison with waxy rice flour and waxy corn starch

The proximate composition, molecular weight distribution and main processing properties of waxy corn flour (WCF) were investigated. Furthermore, waxy corn starch (WCS) and waxy rice flour (WRF) were also determined to discuss the applications of WCF. WCS contained more low-molecular-weight fraction (<5 × 105 g/mol) and had higher polydispesity than waxy rice starch (WRS). The water hydration capacity of WCF was the lowest, whereas it had the highest swelling power at 70 and 80 °C. WCF had the highest pasting temperature of 74.85 °C, whereas that of WRF was 68.40 °C and WCS was 73.25 °C. WRF exhibited the lowest melting enthalpy change with a value of 2.54 ± 0.11 (J/g). The retrogradation resistance of WCF was better than that of WRF and WCS. The degree of retrogradation (DR) of WCF was 9.58 ± 0.59% at 14 d, corresponding to WCS of 25.08 ± 0.44% and WRF of 15.68 ± 0.71%. WRF had the lowest glass transition temperature of −27.4 versus −26.2 °C for WCF and −26.0 °C for WCS. It was found that WCF could be used to directly prepare quick-frozen viscous foods. It could also be used as a stabilizer to improve the quality of staple foods.

Transcriptome analysis of genes involved in starch biosynthesis in developing Chinese chestnut (Castanea mollissima Blume) seed kernels

Chinese chestnut (Castanea mollissima Blume) seed kernels (CCSK) with high quality and quantity of starch has emerged as a potential raw material for food industry, but the molecular regulatory mechanism of starch accumulation in developing CCSK is still unclear. In this study, we firstly analyzed the fruit development, starch accumulation, and microscopic observation of dynamic accumulation of starch granules of developing CCSK from 10 days after flowering (DAF) to 100 DAF, of which six representative CCSK samples (50–100 DAF) were selected for transcriptome sequencing analysis. Approximately 40 million valid reads were obtained, with an average length of 124.95 bp, which were searched against a reference genome, returning 38,146 unigenes (mean size = 1164.19 bp). Using the DESeq method, 1968, 1573, 1187, 1274, and 1494 differentially expressed unigenes were identified at 60:50, 70:60, 80:70, 90:80 and 100:90 DAF, respectively. The relationship between the unigene transcriptional profiles and starch dynamic patterns in developing CCSK was comparatively analyzed, and the specific unigenes encoding for metabolic enzymes (SUSY2, PGM, PGI, GPT, NTT, AGP3, AGP2, GBSS1, SS1, SBE1, SBE2.1, SBE2.2, ISA1, ISA2, ISA3, and PHO) were characterized to be involved potentially in the biosynthesis of G-1-P, ADPG, and starch. Finally, the temporal transcript profiles of genes encoding key enzymes (susy2, pgi2, gpt1, agp2, agp3, gbss1, ss1, sbe1, sbe2.1, sbe2.2, isa1, isa2, isa3, and pho) were validated by quantitative real-time PCR (qRT-PCR). Our findings could help to reveal the molecular regulatory mechanism of starch accumulation in developing CCSK and may also provide potential candidate genes for increasing starch content in Chinese chestnut or other starchy crops.