Moisture distribution model describes the effect of water content on the structural properties of lotus seed resistant starch

Effect of gelatinizing temperature and moisture on the retrogradation of coix starch

Growing snacking trends are boosting the market demand for pre-gelatinized seed flours and the degree of crystallinity of gelatinized starch could be a useful determinant of shelf life and quality. We investigated the effect of gelatinization temperature on purified coix starch (PCS) and the role of added moisture on retrogradation of gelatinized PCS at different temperatures. Disruption of granular structure of PCS with progressive agglomeration resulted in the formation of gelatinized mass with increasing gelatinizing temperature. Amylose content, hydration, degree of gelatinization (DG) and peak viscosity increased while relative crystallinity and short-range structures decreased with elevated gelatinizing temperature. Retrogradation of PGCS increased crystallinity with reduced hydration, peak viscosity without significant change in flow properties and amylose content. Thermal decomposition of PGCS occurred at lower temperature with elevated gelatinizing temperature. PCS was more resistant to thermal decomposition as compared to PGCS. The degree of crystallization affected by added moisture suggested the disruption of molecular arrangement. Higher moisture levels were required for PGCS with lower DG for crystallinity during retrogradation whereas low moisture levels were needed for PGCS with greater DG. Controlling moisture level seems to be critical for the quality and shelf life of the products derived from gelatinized PCS.

Effects of Planting Methods and Varieties on Rice Quality in Northern China

With the continuous improvement in living standards, consumers' demand for rice quality has been increasingly growing. This study analyzed the quality characteristics of different rice varieties under various cultivation methods. This study examined the rice variety Liaoxing 21 (LX21), the upland rice variety Han 9710 (H9710), and the hybrid rice variety Liaoyou 7362 (LY7362) from Liaoning Province to evaluate the effects of transplanting (TP) and direct seeding (DS) on processing, appearance, nutritional, and tasting quality. The results indicated that the planting method (PM) had a relatively minor impact on processing quality. Compared to TP, DS significantly increased grain length (GL) by 1.19%, grain width (GW) by 2.69%, appearance (A) by 2.61%, stickiness (Ss) by 7.15%, degree of balance (DB) by 3.19%, apparent amylose content (AAC%) by 6.20%, fa by 0.66%, fa/fb3 by 5.34%, and protein content (PC) by 19.93%. However, DS significantly reduced the grain length/width ratio (GL/W) by 1.03%, chalky grain rate (CGR) by 46.00%, chalkiness (CH) by 52.76%, and fb3 by 4.23%. Compared to DS, TP resulted in a higher peak viscosity (PV), final viscosity (FV), and pasting temperature (PaT), whereas setback (SB) was lower. Among the tested varieties, LX21 exhibited superior milled rice rate (MRR), head rice rate (HRR), GL, GL/W, A, Ss, DB, taste value (T), and FV compared to H9710 and LY7362, while demonstrating significantly lower CGR, CH, hardness (H), fa, trough viscosity (TV), and peak time (PeT). Under the same planting conditions, the conventional rice variety LX21 demonstrated excellent processing, appearance, and taste quality, whereas H9710 exhibited favorable nutritional quality and Rapid Visco Analyzer (RVA) characteristics. Meanwhile, we also analyzed the correlation between temperature/light conditions and nutritional quality, as well as RVA profiles. The results showed that variations in temperature and light were closely associated with amylopectin accumulation and starch pasting properties. This study highlights the findings that selecting the appropriate PMs and japonica rice varieties can effectively enhance overall rice quality. In the medium maturing regions of Liaoning Province, adopting DS with medium-early maturing japonica rice varieties offers an optimal production strategy for achieving high quality, high yield, and efficient utilization of temperature and light resources.

Nutrition and Gut Health: Preparation and Efficacy of Resistant Starch

Resistant starch (RS) refers to starch varieties that resist digestion by human digestive enzymes. Owing to its distinctive physicochemical attributes and functional capabilities, RS has gained a wide range of applications as a dietary fiber and prebiotic. In terms of structure and functions, RS can be categorized into five distinct types: RS1 through RS5. These types offer dietary benefits, contributing to improved colonic health, the modulation of microbial communities, the reduction in gallstone formation, the enhancement of mineral absorption, and alterations in fat oxidation potential. From a technical standpoint, RS can be manufactured through an array of physical, enzymatic, and chemical modifications. This paper presents a comprehensive review of the existing literature, summarizing the classification, structural features, raw material origins, preparation methodologies, and functionalities of RS. Furthermore, new production technologies and applications of RS, such as 3D printing, provide valuable insights.

Spatial exposure and oxidative accumulation of reactive hydroxyl groups in starch retrogradation through transglucosidase and hexose oxidase

To investigate the potential of inhibiting starch retrogradation by modifying the functional groups of starch, transglucosidase (TG) was used to facilitate active hydroxyl groups to be exposed through increasing branching degree. Subsequently, hexose oxidase (HOX) advantageously promoted the oxidation of starch chains and increased spatial repulsion of starch backbone. The Fukui Function revealed that the oxygen atoms at the C3 and C4 positions on glucose units had a higher oxidation tendency. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis confirmed that the reactive hydroxyl groups underwent an oxidation process with increasing HOX treatment time. From the crystal structure parameters, the c-axis of native corn starch modified by TG for 16 h and HOX for 48 h (or TGHOX-48) was shortened from 16.92 to 16.32 Å and in the long-term retrogradation, TGHOX-48 exhibited the lowest starch retrogradation rate (0.22).

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

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

Effect of Rice Protein on the Gelatinization and Retrogradation of Rice Starch with Different Moisture Content

Rice protein and moisture content are pivotal in the gelatinization and retrogradation processes of rice starch. This study aimed to explore the influence of rice protein on these processes by preparing rice starch gels with varying moisture levels and incorporating rice protein. At a high moisture content of 1:6, rice protein exhibited a minimal effect on the gelatinization properties of rice starch but significantly retarded the retrogradation of the starch gel. At intermediate moisture levels of 1:4 and 1:2, the rice starch gels showed pronounced retrogradation. However, rice protein was effective in inhibiting this retrogradation at a 1:4 moisture content, while its inhibitory effect diminished at a 1:2 moisture content. Under low moisture conditions of 1:1, the gelatinization of rice starch was markedly constrained by the limited water availability, but rice protein mitigated this constraint. Conversely, at this moisture level, rice protein promoted the retrogradation of the rice starch gel during the retrogradation process. The findings of this study offer a theoretical foundation that could inform the production of rice-based products.

Research on the quantitative relationship of the viscosity reduction effect of large-ring cyclodextrin on potato starch during gelatinization process and mechanism analysis

Starch is extensively used across various fields due to its renewable properties and cost-effectiveness. Nonetheless, the high viscosity that arises from gelatinization poses challenges in the industrial usage of starch at high concentrations. Thus, it's crucial to explore techniques to lower the viscosity during gelatinization. In this study, large-ring cyclodextrins (LR-CDs) were synthesized from potato starch (PS) by using 4-α-glucanotransferase and then added to PS to alleviate the increased viscosity during gelatinization. The results from rapid viscosity analyzer (RVA) demonstrated that the inclusion of 5 % (w/w) LR-CDs markedly reduced the peak viscosity (PV) and final viscosity (FV) of PS by 49.85 % and 28.17 %. In addition, there was a quantitative relationship between PV and LR-CDs. The equation was fitted as y = 2530.73×e-x/2.48+1832.79, which provided a basis for the regulation of PS viscosity. The mechanism of LR-CDs reducing the viscosity of PS was also studied. The results showed that the addition of LR-CDs inhibited the gelatinization of PS by enhancing orderliness and limiting water absorption, resulting in a decrease in viscosity. This study provides a novel method for reducing the viscosity of starch, which is helpful for increasing its concentration and reducing energy consumption in industrial applications.

Freezing rate's impact on starch retrogradation, ice recrystallization, and quality of water-added and water-free quick-frozen rice noodles

The study evaluated the effect of freezing rate on the quality of water-added quick-frozen rice noodles and water-free quick-frozen rice noodles. Results indicated that the retrogradation enthalpy, relative crystallinity, freezable water content, and cooking loss of water-added quick-frozen rice noodles were higher than those of water-free quick-frozen rice noodles with increasing storage time. Furthermore, ice recrystallization accelerated the deterioration of the quality of the rice noodles, resulting in the enlargement of the pores within the rice noodles and the formation of many pores on the surface. This phenomenon was particularly evident in the rice noodles of Y-40 °C (freezing with water at -40 °C) and Y-60 °C (freezing with water at -60 °C). After 28 days of frozen storage, the hardness increased by 83.83 % for rice noodles of Y-20 °C (freezing with water at -20 °C), while the hardness decreased by 51.68 % and 45.80 %, respectively, for rice noodles of Y-40 °C and Y-60 °C. Consequently, the impact of the freezing rate on the quality of water-added quick-frozen rice noodles is more pronounced than that of water-free quick-frozen rice noodles. Moreover, a higher freezing rate can delay the deterioration of the quality of frozen rice noodles by postponing starch retrogradation and inhibiting ice recrystallization.

Trehalose-conjugated lentil-casein protein complexes prepared by structural interaction: Effects on water solubility and protein digestibility

The two limiting factors for lentil protein utilization are water solubility and digestibility. In this study, we utilized two non-thermal techniques: (1) protein complexation of lentil and casein proteins using the pH-shifting method and (2) protein conjugation with trehalose to produce trehalose-conjugated lentil-casein protein complexes (T-CPs) with enhanced water solubility and digestibility. The protein structure of the T-CPs was analyzed for secondary protein structure, conformation protein, and tertiary protein structure using Fourier-transform infrared, UV, and fluorescence spectroscopies, respectively. The surface hydrophobicity and surface charge of T-CPs solution at pH 7.0 changed significantly (P < 0.05). Using these two non-thermal techniques, the water solubility and digestibility of T-CPs increased significantly (P < 0.05) by 85 to 89 % and 80 to 85 %, respectively. The results of this study suggested that these non-thermal techniques could enhance the surface and protein structure properties, improving water solubility and digestibility.

Retrogradation behaviors of damaged wheat starch with different water contents

The retrogradation behaviors of five damaged wheat starches (DS) after milling 0, 30, 60, 90, and 120 min with different water contents (33, 50, 60 %) were evaluated. Milling treatment increased DS content and developed an agglomeration of small particles. After 7 days of storage, the recrystallinity and long-range ordered structure of starch pastes were increased with the contents of DS and water. This process led to a lower setback viscosity and poor leaching of amylose. LF-NMR indicated a conversion from tightly bound water and free water to weakly bound water. During storage, DS12 with 60 % water content had the highest retrogradation tendency where the retrogradation enthalpy increased by 1.5 J/g and 2.2 J/g compared with DS0 with 60 % and DS12 with 33 % water content. DS with higher water content promoted the water mobility and made the starch molecular chains migrated conveniently. These changes facilitated the recrystallinity process during retrogradation period.

Evaluation of digestibility, solubility, and surface properties of trehalose-conjugated quinoa proteins prepared via pH shifting technique

Soluble trehalose-conjugated quinoa proteins (T-QPs) were effectively prepared using the pH-shifting mechanism. The structural properties of the T-QPs were evaluated using a comparative evaluation, which included analyzing the amide I, surface charge and hydrophobicity, protein conformation, thermal stability, and protein structures. The results suggested that the development of the T-QPs was influenced mainly by no-covalent bonds. These interactions significantly influenced (P < 0.05) the quinoa proteins' conformation and higher-protein structure. T-QP had significant (P < 0.05) surface properties. Furthermore, the T-QPs exhibited improved solubility (79.7 to 88.4%) and digestibility (79.8 to 85.1%). Therefore, quinoa protein proved an excellent plant-based protein for conjugation with disaccharides. These findings provide significant insight into the potential development of modified proteins with enhanced solubility and digestibility by creating trehalose-conjugated plant-based proteins.

Purple rice starch in wheat: Effect on retrogradation dependent on addition amount

While individual starch types may not possess the ideal gelatinization and retrogradation properties for specific applications, the amalgamation of multiple starch varieties might bestow desirable physicochemical properties upon resulting starch-based products. This study explored the impact of incorporating purple rice starch (PRS), as a novel starch variant (up to 15 % PRS), on the gelatinization and retrogradation (within 14 days) of regular wheat starch (WS). Rheological and texture assessments demonstrated that the introduction of PRS diminished the viscoelasticity and hardness of fresh WS paste. Additionally, in the case of retrograded WS pastes stored at 4 °C for 1-14 days, the incorporation of 10 % or 15 % PRS effectively retarded the reduction in transparency and significantly reduced hardness, retrogradation degree, the ratio of absorbance at 1047/1017 cm-1, and relative crystallinity. Notably, 10 % PRS results in a more pronounced effect. Conversely, 5 % PRS induced an opposing impact on retrograded WS post-storage. Moreover, scanning electron microscopy revealed that as the proportion of PRS increased, the microstructure of gelatinized WS-PRS closely resembled that of pure PRS. In conclusion, the diverse effects of varying PRS proportions on WS alter the texture and characteristics of starch-based foods, underscoring the potential of starch blending for improved applications.

Effect of lotus seed resistant starch on the bioconversion pathway of taurocholic acid by regulating the intestinal microbiota

Taurocholic acid (TCA) is abundant in the rat intestine and has multiple health benefits. In the gut, intestinal microbiota can transform TCA into different bile acid (BA) derivatives, with the composition of microbiota playing a crucial role in the transformation process. This study aims to investigate how lotus seed resistant starch (LRS) can regulate microbiota to influence BA transformation. A fecal fermentation study was conducted in vitro, using either LRS, high-amylose maize starch (HAMS), or glucose (GLU) to analyze microbiota composition, BA content, and metabolic enzyme activities over different fermentation times. Bioinformatics analysis found that LRS increased the relative abundance of Enterococcus, Bacillus, and Lactobacillus, and decreased Escherichia-Shigella, compared with HAMS and GLU. LRS also reduced total BA content and accelerated the conversion of TCA to cholic acid, deoxycholic acid, and other derivatives. These results reveal that LRS and GLU tend to mediate the dehydroxy pathway, whereas HAMS tends to secrete metabolic enzymes in the epimerization pathway. Therefore, the evidence that LRS may regulate TCA bioconversion may benefit human colon health research and provide an important theoretical basis, as well as offer new concepts for the development of functional foods.

Physicochemical, Quality and Flavor Characteristics of Starch Noodles with Auricularia cornea var. Li. Powder

Auricularia cornea var. Li., as an edible mushroom rich in various nutrients, could be widely used in noodle food. This study aimed to investigate the effect of Auricularia cornea var. Li. (AU) powder on the gel properties, structure and quality of starch noodles. Taking the sample without adding AU powder as a control, the addition of AU powder enhanced the peak viscosity, trough viscosity, final viscosity, breakdown, setback, peak time, gelatinization temperature, G' (storage modulus) and G'' (loss modulus). Meanwhile, the incorporation of AU powder significantly enhanced the stability of the starch gel structure and contributed to a more ordered microstructure also promoting the short-term aging of starch paste. In vitro digestion results displayed lower rapid digestibility (21.68%) but higher resistant starch content (26.58%) with the addition of AU powder and increased breaking rate, cooking loss, swelling index and a* and b* values. However, it decreased dry matter content and L*, particularly the reducing sugar content significantly increased to 4.01% (p < 0.05), and the total amino acid content rose to 349.91 mg/g. The GC-IMS library identified 51 VOCs, and the OPLS-DA model classified 18 VOCs (VIP > 1). Overall, the findings indicate that starch noodles with the addition of AU powder may provide greater nutritional quality, gel stability and starch antidigestibility.

Physicochemical properties of a novel chestnut porous starch nanoparticle

A novel chestnut porous starch nanoparticle (PSNP) was successfully synthesized, combining the properties of starch nanoparticle (SNP) and porous starch. The SNP obtained through ultrasonic and acid hydrolysis, exhibited a smaller particle size (173.9 nm) and a higher specific surface area (SSA) compared to native starch. After the synergistic hydrolysis by α-amylase and glucoamylase, the porous structure appeared on the surface of SNP. The prepared PSNP had a size of 286.3 nm and the highest SSA. In the adsorption experiments, PSNP showed higher capacities for adsorbing water, oil and methylene blue (MB) compared to other samples. The acid and enzymatic treatments resulted in a decrease in the levels of total starch content and amylose ratio. Furthermore, the treatments increased the levels of relative crystallinity (RC) and solubility, while decreasing the short-range ordered structure and swelling ratio at high temperatures. It was observed that the SSA of starch granules positively correlated with the MB and water adsorption capacity (WAC), solubility, and RC. These findings highlight the potential of the novel PSNP as an efficient adsorbent for bioactive substances and dyes.

Alu'datt M, R. Al Qudsi F, Tan TC, A. Razzak Mahmood A, Maghaydah S. Molecular forces driving protein complexation of lentil and whey proteins: Structure-function relationships of trehalose-conjugated protein complexes on protein digestibility and solubility

Plant-based proteins are often associated with a range of health benefits. Most research primarily investigates pea and soy proteins, while lentil proteins received minimal attention. This study evaluates the effect of protein complexation (using the pH-shifting technique) coupled with trehalose conjugation on lentil and whey proteins. The protein structures after the modification were analysed using spectroscopic methods: Fourier-transform infrared, ultraviolet spectra, and fluorescence spectra. The amide group I, conformation protein, and tertiary structure of the trehalose-conjugated lentil-whey protein complexes (T-LWPs) showed significant changes (P < 0.05). Moreover, the surface properties (surface hydrophobicity and charges) of T-LWPs were significantly modified (P < 0.05), from 457 to 324 a.u and from 36 to -40 mV, respectively. Due to these modifications on the protein structures, the protein digestibility (80-86%) and water solubility (90-94.5%) of T-LWPs increased significantly (P < 0.05) with the increase in the trehalose concentration, from 0 (control) to 5% (w/w), respectively. This study suggested that coupling protein complexation and trehalose conjugation can enhance the overall properties of lentil-based protein complexes. With this enhancement, more opportunities in the utilisation of lentils are to be expected.

Synergistic effect of enzymatic pre-treatment and amylose-lipid complex construction on the physicochemical properties of maize starch

In this study, the effects of maltogenic amylase (MAA) pre-treatment and starch-fatty acid complex construction on the physicochemical properties of maize starch (MAS) were investigated. The average chain length of MAA-modified MAS was found to decrease from 18.15 to 14.92. Moreover, MAA pre-treatment of starch induced the formation of a V-type complex. This behaviour was demonstrated by the higher diffraction intensity, enzymatic resistance and short-range ordering of the samples pre-treated with MAA compared with unmodified samples. X-ray diffraction and rheological analysis revealed that the re-crystallisation peak intensities and storage modulus of MAA-MAS-lauric acid (LA)/stearic acid (SA) complexes were lower than those of MAA-starches, MAS-LA/SA complexes and control. The rate of starch re-crystallisation was effectively decreased by the combination of MAA pre-treatment and V-type complex construction. The anti-retrogradation (long-term) characteristics of the tested samples were in the following order: MAA-MAS-LA/SA complexes > MAA-starches > MAS-LA/SA complexes > control.

Research Progress in Modifications, Bioactivities, and Applications of Medicine and Food Homologous Plant Starch

Starchy foods are an essential part of people's daily diet. Starch is the primary substance used by plants to store carbohydrates, and it is the primary source of energy for humans and animals. In China, a variety of plants, including edible medicinal plants, such as Pueraria root, yam tuber and coix seed, are rich in starch. However, limited by their inherent properties, kudzu starch and other starches are not suitable for the modern food industry. Natural starch is frequently altered by physical, chemical, or biological means to give it superior qualities to natural starch as it frequently cannot satisfy the demands of industrial manufacturing. Therefore, the deep processing market of modified starch and its products has a great potential. This paper reviews the modification methods which can provide excellent functional, rheological, and processing characteristics for these starches that can be used to improve the physical and chemical properties, texture properties, and edible qualities. This will provide a comprehensive reference for the modification and application of starch from medicinal and edible plants.

Effect of Different Edible Trichosanthes Germplasm on Its Seed Oil to Enhance Antioxidant and Anti-Aging Activity in Caenorhabditis elegans

The seeds of various Trichosanthes L. plants have been frequently used as snacks instead of for traditional medicinal purposes in China. However, there is still a need to identify the species based on seeds from Trichosanthes germplasm for the potential biological activities of their seed oil. In this study, 18 edible Trichosanthes germplasm from three species were identified and distinguished at a species level using a combination of seed morphological and microscopic characteristics and nrDNA-ITS sequences. Seed oil from the edible Trichosanthes germplasm significantly enhanced oxidative stress tolerance, extended lifespan, delayed aging, and improved healthspan in Caenorhabditis elegans. The antioxidant activity of the seed oil exhibits a significant positive correlation with its total unsaturated fatty acid content among the 18 edible Trichosanthes germplasm, suggesting a genetic basis for this trait. The biological activities of seed oil varied among species, with T. kirilowii Maxim. and T. rosthornii Harms showing stronger effects than T. laceribractea Hayata.

Mechanistic insights into the enhanced texture of potato noodles by incorporation of small granule starches

Potato noodles are a popular food due to their unique texture and taste, but native potato starch often fails to meet consumer demands for precise textural outcomes. The effect of blending small granule (waxy amaranth, non-waxy oat and quinoa) starch with potato starch on the properties of noodles was investigated to enhance quality of noodles. Morphological results demonstrated that small granule starch filled gaps between potato starch granules, some of which gelatinized incompletely. Meanwhile, XRD and FTIR analysis indicated that more ordered structures and hydrogen bonding among starch granules increased with addition of small granule starch. The addition of oat or quinoa starch increased gel elasticity, decreased viscosity of the pastes, and increased the tensile strength of noodles, while addition of 30 % and 45 % waxy amaranth starch did not increase G' value of gel or tensile strength of noodles. These results indicated that amylose molecules played an important role during retrogradation, and may intertwine and interact with each other to enhance the network structure of starch gel in potato starch blended with oat or quinoa starch. This study provides a natural way to modify potato starch for desirable textural properties of noodle product.

Multi-scale structural characteristics of black Tartary buckwheat resistant starch by autoclaving combined with debranching modification

The impact of autoclaving or autoclave-debranching treatments on the multi-scale structure of resistant starch (RS) and the relationship with starch digestion remains unclear, despite their widespread use in its preparation. This work investigated the relationship between RS structure in black Tartary buckwheat and its digestibility by analyzing the effects of autoclaving and autoclave-debranching combined treatments on the multi-scale structure of RS. The results showed that black Tartary buckwheat RS exhibited a more extensive honeycomb-like network structure and enhanced thermal stability than either black Tartary buckwheat native starch (BTBNS) or common buckwheat native starch (CBNS). Autoclaving and autoclaving-debranching converted A-type native starch to V-type and possibly the formation of flavonoid-starch complexes. Autoclaving treatment significantly increased the proportion of short A chain (DP 6-12) and the amylose (AM) content, reduced the viscosity and the total crystallinity. Notably, the autoclave-debranching co-treatment significantly enhanced the resistance of starch to digestion, promoted the formation of perfect microcrystallines, and increased the AM content, short-range ordered degree, and the proportion of long B2 chain (DP 25-36). This study reveals the relationship between the multi-scale structure and digestibility of black Tartary buckwheat RS by autoclaving combined with debranching modification.

The structural properties and resistant digestibility of maize starch-glyceride monostearate complexes

This study investigated the effects of pullulanase debranching on the structural properties and digestibility of maize starch (MS)-glyceryl monostearate (GMS) complexes. According to our results, the apparent amylose content of MS increased from 36.34 % to 95.55 % and complex index reached 93.09 % after 16 h of pullulanase debranching. The crystallinity of prepared MS-GMS complexes increased to 33.24 % with a blend of B-type and V-type crystals. The surface of prepared MS-GMS complexes granules emerged more small lamellar crystals tightly adhering to the surface of granules. The Fourier transforms infrared spectroscopy analysis showed that debranching pretreatment MS-GMS complexes exhibited higher levels of short-range orders structure. These results indicated that maize starch was favorable to form more ordered starch-lipid complexes structure after debranching pretreatment, which resulted in the restriction of starch hydrolysis. In vitro digestion data implied that resistant starch (RS) content increased with the extension of the debranching time, and the highest RS content (69.58 %) appeared with 16 h pullulanase debranching. This work suggests that debranching pretreatment could be an efficient way to produce ordered starch-lipid complexes with controllable structure and anti-digestibility.

Changes in physiochemical properties and in vitro digestion of corn starch prepared with heat-moisture treatment

To investigate the effect of heat-moisture treatment (HMT) on the physiochemical properties and in vitro digestibility of corn starch, the pasting behavior, viscoelasticity, thermal properties, long/short range structure, morphology and in vitro digestion of corn starch treated with different HMT conditions (HMT-20, 25, 30, 35 and 40 %) were characterized. Results indicated that after HMT, the pasting and disintegration behaviors of corn starch were affected and correlated with the moisture content. The dynamic viscoelasticity of corn starch was changed, and when glassy conditions were reached, the elastic properties decreased with increasing moisture while the viscous properties increased, especially for the HMT-40 %. The thermal stability of starch was improved by HMT, although the enthalpy of pasting (ΔH) was reduced. Additionally, the HMT processing also promoted the conversion of RDS to SDS and/or RS (SDS and RS increased to 39.80 % and 31.68 % for HMT-40 %, respectively), which might attribute to the rearrangement of free starch molecules. The present work provides a potential approach to make functional starches with healthy properties.

Gut microbiota-metabolic axis insight into the hyperlipidemic effect of lotus seed resistant starch in hyperlipidemic mice

We investigated the hyperlipidemic effect of different doses of lotus seed resistant starch (low-, medium and high-dose LRS, named as LLRS, MLRS and HLRS, respectively) in hyperlipidemic mice using gut microbiota-metabolic axis compared to high-fat diet mice (model control group, MC). Allobaculum was significantly decreased in LRS groups compared to MC group, while MLRS promoted the abundance of norank_f_Muribaculaceae and norank_f_Erysipelotrichaceae. Moreover, supplementation of LRS promoted cholic acid (CA) production and inhibited deoxycholic acid compared to MC group. Among, LLRS promoted formic acid, MLRS inhibited 20-Carboxy-leukotriene B4, while HLRS promoted 3, 4-Methyleneazelaic acid and inhibited Oleic acid and Malic acid. Finally, MLRS regulate microbiota composition, and this promoted cholesterol catabolism to form CA, which inhibited serum lipid index by gut microbiota-metabolic axis. In conclusion, MLRS can promote CA and inhibit medium chain fatty acids, so as to play the best role in lowering blood lipids in hyperlipidemia mice.

Structural, functional and mechanistic insights uncover the role of starch in foxtail millet cultivars with different congee-making quality

Ten foxtail millet cultivars with different congee-making quality were investigated for relationships between starch structures, functional properties and congee-making qualities. Swelling power, pasting peak viscosity (PV) and setback (SB), gel hardness and resilience, and gelatinization onset (T_o), peak (T_p) and range (R) temperature were correlated with congee-making performance significantly. Good eating-quality cultivars with these parameters were in the range of 15.41-18.58 %, 3095-3279 cp, 1540-1745 cp, 430-491 g, 0.47-0.57, 64.43-65.28 °C, 69.97-70.32 °C and 23.38-24.52 °C, respectively. Correlation analysis showed that amylose, amylopectin B₂ chains and A₂₁ were essential parameters controlling the functional properties. Amylose molecules with linear molecular morphology would cause crystal defects and a wide range of molecular weight distribution. Additionally, they were more prone to re-association, which influenced the PV, SB, T_o, T_p and gel hardness. B₂ chains impacted the gelatinization temperature range (R), gel resilience and swelling behavior by affecting the alignment of double helices and the size of starch particles and pores. Starch with more binding sites of bound water (A₂₁) tended to leach from the swelling granules easily and contributed to higher values of PV. The content of amylose, B₂ chains and A₂₁ of good eating-quality cultivars were 16.19-18.46 %, 11.60-11.69 % and 96.50-97.02 %, respectively.

Retrogradation behavior of starch dough prepared from damaged cassava starch and its application in functional gluten-free noodles

A novel starch-based model dough used to exploit staple foods was demonstrated to be feasible, which was based on damaged cassava starch (DCS) obtained by mechanical activation (MA). This study focused on the retrogradation behavior of starch dough and the feasibility of its application in functional gluten-free noodles. Starch retrogradation behavior was investigated by low field-nuclear magnetic resonance (LF-NMR), X-ray diffraction (XRD), scanning electron microscope (SEM), texture profile and resistant starch (RS) content analysis. During starch retrogradation, water migration, starch recrystallization and microstructure changes were observed. Short-term retrogradation could significantly alter the texture properties of starch dough, and long-term retrogradation promoted the formation of RS. The damage level influenced starch retrogradation, and damaged starch with the increasing damage level was beneficial to facilitate the starch retrogradation. Gluten-free noodles made from the retrograded starch had acceptable sensory quality, with darker color and better viscoelasticity than Udon noodles. This work provides a novel strategy for the proper utilization of starch retrogradation for the development of functional foods.

Effect of Physical and Enzymatic Modifications on Composition, Properties and In Vitro Starch Digestibility of Sacred Lotus (Nelumbo nucifera) Seed Flour

In this study, native lotus seed flour (N-LSF) was modified by different methods, namely, partial gelatinization (PG), heat−moisture treatment (HMT), or pullulanase treatment (EP). Their composition, functional properties, starch composition, and estimated glycemic index (eGI) were compared. PG contained similar protein, soluble dietary fiber, and insoluble dietary fiber contents to N-LSF, while those of HMT and EP differed from their native form. PG increased rapid digestible starch (RDS) but decreased resistant starch (RS); while HMT and EP increased amylose and RS contents to 34.57−39.23% and 86.99−92.52% total starch, respectively. Such differences led to the different pasting properties of the modified flours rather than PG, which was comparable to the native flour. HMT had limited pasting properties, while EP gave the highest viscosities upon pasting. The eGI of all samples could be classified as low (<50), except that of PG, which was in the medium range (60). It was plausible that lotus seed flour modified either with HMT or EP could be used as carbohydrate source for diabetes patients or health-conscious people.

Appropriate microwave improved the texture properties of quinoa due to starch gelatinization from the destructed cyptomere structure

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Microwave dispersed quinoa starch aggregates into independent granules.

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Dispersed starch granules were hydrated and gelatinized to form network structure.

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Microwave maintained the crystal form while changed the crystallinity.

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Excessive microwave makes the starch partially gelatinize and formed blocks.

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Moderate microwave treatment can improve the hardness and stickiness of quinoa.

Texture characteristics of quinoa under microwave (MW) irradiation were studied from the perspective of starch gelatinization. MW reduced the light transmittance and increased the hardness and stickiness of quinoa. Microstructure showed that MW dispersed the vesicular structure of starch aggregates into separate starch particles, resulting in the full hydration of starch and water molecules to form denser network structures. The value of peak viscosity and setback decreased in RVA after MW treatment, but the gelatinization temperature remained stable. DSC further proved that moderate MW treatment could reduce the gelatinization enthalpy of starch and made quinoa accessible to gelatinize. However, XRD showed that the crystal structure of starch was preserved, but the crystallinity increased. Finally, low field NMR showed that moderate MW stimulated the full hydration of starch to form denser network structures, while excessive MW treatment made starch partially gelatinize and form rigid structure, resulting in negative texture properties.

Lotus seed resistant starch ameliorates high-fat diet induced hyperlipidemia by fatty acid degradation and glycerolipid metabolism pathways in mouse liver

We investigated the potential efficacy and underlying mechanisms of Lotus seed Resistant Starch (LRS) for regulating hyperlipidemia in mice fed a High-fat Diet (HFD). Mouse were fed a normal diet (Normal Control group, NC group), HFD alone (MC group), HFD plus lovastatin (PC group), or HFD with low/medium/high LRS (LLRS, MLRS, and HLRS groups, respectively) for 4 weeks. LRS supplementation significantly decreased body weight and significantly reduced serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipopro-tein cholesterol compared with the MC group. LRS also significantly alleviated hepatic steatosis, especially in the MLRS group, which also showed a significantly reduced visceral fat index. LLRS supplementation significantly regulated genes associated with glycerolipid metabolism and steroid hormone biosynthesis (Lpin1 and Ugt2b38), MLRS significantly regulated genes related to fatty acid degradation, fatty acid elongation, and glycerolipid metabolism (Lpin1, Hadha, Aldh3a2, and Acox1), whereas HLRS significantly regulated genes related to fatty acid elongation and glycerolipid metabolism (Lpin1, Elovl3, Elovol5, and Agpat3). The fatty acid-degradation pathway regulated by MLRS thus exerts better control of serum lipid levels, body weight, visceral fat index, and liver steatosis in mice compared with LLRS- and HLRS-regulated pathways.

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.

Influence of the Addition of Extruded Endogenous Tartary Buckwheat Starch on Processing and Quality of Gluten-Free Noodles

Extruded starch could be used as a thickener for food processing due to its pre-gel properties. This study aimed to explore the influence of the addition of extruded endogenous Tartary buckwheat starch (ES) on the process and quality of gluten-free noodles. ES was mixed with Tartary buckwheat flour in different proportions (10–40%) to prepare the blended flour and noodles. When the content of ES was increased, the swelling power of blended flour at 90 °C had no significant changes, and the decrease in peak viscosity of blended flour was reduced. This indicated that the high-content ES could afford better thermal stability for blended flour and inhibit the swelling ability. The higher level of ES was beneficial to the formation and stabilization of dough, and the improvement of noodle tensile strength. Furthermore, there was no difference in cooking loss between noodles with 30% and 40% ES addition. The microstructure and water distribution of the noodles prepared by blended flour indicated that the gel-entrapped structure organized by the higher content ES could be closely related to the above results. In conclusion, higher ES could contribute to improving the processing properties and quality of noodles.

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.

Ordered structural changes of retrograded starch gel over long-term storage in wet starch noodles

Temperature-induced structural variations of retrograded starch gel during long-term storage were investigated in a real food system (wet starch noodles). Fresh starch noodles presented a B-type XRD pattern containing 8.82% crystallinity and 16.04% double helices. In the first 2 weeks, double helices of starch chain formed long-range ordered structure leading to increased crystallinity, and such structural transformation was positively correlated with increasing storage temperature (from 4 °C to 35 °C) and storage time. However, with the extension of storage time to 12 weeks, the disorganization of supra-molecular structure was likely to be observed by decreased crystallinity, double helix and water mobility. Besides, we propose that the area and intensity of Raman band at 2910 cm^-1 can be a good indicator for evaluating perfection of crystallinity in starch noodles. These results contributed to a better understanding of mechanisms underlying molecular order changes of retrograded starch gel product during long-term storage.

Evaluation of cooking performance, structural properties, storage stability and shelf life prediction of high-moisture wet starch noodles

Cooking performance, micro- and molecular structure, storage stability and shelf-life prediction of high-moisture wet starch noodles (SN) were investigated. SEM images revealed that compared to dried SN, cooked wet SN had more evenly honeycomb-like network with smaller size of pores, indicating stronger interaction among molecules and causing favorable cooking performance. XRD and ATR-FTIR results evidenced that wet SN contained more complete crystallites and higher proportion of crystalline region. During storage, the quality decay of wet SN was mainly associated to the increment of total aerobic viable count (TAVC), titrable acidity and amylase, as well as the decreased textural hardness, overall acceptability and lightness. Based on TAVC, titrable acidity and overall acceptability, predicted shelf-life of vacuum-packed wet SN at 25 °C was 15.31, 21.54 and 16.65 weeks respectively, with relative error all within 20%, proving that the validated model could be an effective tool for monitoring the shelf-life of wet SN.

Characterization of complexes formed between debranched starch and fatty acids having different carbon chain lengths

Recently, amylose-lipid complexes have attracted widespread attention because of their various applications. However, DBS complexed with fatty acids of different carbon chain length are rarely studied. This study aimed to probe the complexation of DBS with saturated fatty acids having different carbon chain lengths (C6-C18). The results revealed that DBS was able to form V-type complexes with all the fatty acids considered. Compared to DBS, the relative crystallinity of the complexes increased 2-3 times. DBS with lauric acid and myristic acid formed three types V-type complexes (type I, type IIa, and type IIb). The complexing index followed the order of hexanoic acid > octanoic acid > capric acid > lauric acid > myristic acid > palmitic acid > stearic acid. Furthermore, lauric acid and myristic acid formed complexes with DBS more easily compared with other fatty acids.

Small Auxin Up RNAs influence the distribution of indole-3-acetic acid and play a potential role in increasing seed size in Euryale ferox Salisb

BACKGROUND

Aquatic Euryale ferox Salisb. is an economically important crop in China and India. Unfortunately, low yield limitations seriously hinder market growth. Unveiling the control of seed size is of remarkable importance in improvement of crops. Here, we generated a new hybrid line (HL) with larger seeds by crossing South Gordon Euryale and North Gordon Euryale (WT) which hasn't been reported before. However, the functional genes and molecular mechanisms controlling the seed size in Euryale ferox Salisb. remain unclear. In this study, we focused on the differentially expressed genes in the auxin signal transduction pathway during fruit development between HL and WT to explore candidate regulatory genes participated in regulating seed size.

RESULTS

Both concentration and localization of indole-3-acetic acid (IAA) at two growth stages of fruits of WT and HL were detected by LC-MS and immunofluorescence. Although IAA content between the two lines did not differ, IAA distribution was significantly different. To elucidate the mechanism and to seek the key genes underlying this difference, RNA-seq was performed on young fruits at the two selected growth stages, and differentially expressed genes related to the auxin transduction pathway were selected for further analysis.

CONCLUSION

Hybrid Euryale ferox Salisb. expressed significant heterosis, resulting in non-prickly, thin-coated, large seeds, which accounted for the significantly larger yield of HL than that of WT. Our study indicated that Small Auxin Up RNAs (SAURs) -mediated localization of IAA regulates seed size in Euryale ferox Salisb. We found that some SAURs may act as a positive mediator of the auxin transduction pathway, thereby contributing to the observed heterosis.