Structural characteristics and crystalline properties of lotus seed resistant starch and its prebiotic effects

Type 3 resistant starch prepared from jackfruit alleviated the hyperlipidemia via gut microbiota regulation

Although resistant starch (RS) isolated from raw starch exhibits established regulatory effects on the mouse gut microbiota and associated hyperlipidemia, critical questions persist regarding RS in heated foods - the predominant form in the human diets, namely, the role of RS from heated food in the regulation of hyperlipidemia through gut microbiota is still unclear. This study evaluated the effects of a RS (jackfruit heated resistant starch, JFRS3) from heat-treated jackfruit native starch (JFNS) on hyperlipidemia in golden hamster gut microbes. Compared with JFNS, JFRS3 developed an irregular block-like shape with numerous grooves, exhibited more ordered structures (R1047/1022: 2.952 and R1022/995: 0.964) and greater crystallinity (relative crystallinity (RC): 21.96 %), and transformed into a C-type crystalline structure. Additionally, JFRS3 demonstrated significant antihyperlipidemic effects, which included an increase in high-density lipoprotein cholesterol (HDLC) levels (4.36 mmol/L) and reductions in triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels (14.39, 4.55, and 4.61 mmol/L, respectively), thereby alleviating liver fatty lesions, reducing fat accumulation, and inhibiting adipocyte enlargement. These effects were closely linked to intestinal microbial changes, such as specific microbial enrichment and enhanced gut microbial diversity, potentially influenced by the structural properties of JFRS3. Furthermore, the consumption of JFRS3 was more effective in slowing weight gain and improving blood lipid profiles compared with raw RS present in JFNS. These findings prove that JFRS3 modulates hyperlipidemia induced by a high-fat diet and contributes to the development of alternative strategies for managing high-fat-diet-associated hyperlipidemia.

Longan seeds used as novel resources to prepare resistant starch: structure, properties and digestion

In the present study, the preparation of resistant starch from longan seeds was investigated, and the properties and in-vitro digestibility of this resistant starch were further determined. Longan seed resistant starch (LRSI, LRS-II, and LRS-III) was successfully prepared, by once retrogradation, twice retrogradation and combining retrogradation and debranching, respectively. All LRS groups had higher amylose content (from 422.1 to 462.4 g/kg) and increased particle size than those of longan seed starch (LSS). Meanwhile, the resistant starch exhibited a B-type crystalline structure, and showed a block, uneven and irregular microstructure. Compared with LSS group, LRS groups exhibited higher crystallinity (from 49.03 to 56.14 %), more of short-range ordered structure (DO: from 0.771 to 0.775, DD: 0.808 to 0.942), and lower molecular weight (Mw: from 2.43 to 2.81 × 105 Da). Moreover, LRS groups showed lower viscosity during gelatinization and weaker binding capability to iodine than those of LSS group. Furthermore, all LRS groups exhibited strong resistance to enzymatic hydrolysis with high content of resistant starch (from 360 to 398 g/kg) and low rate of in-vitro digestion (k: from 23.87 to 33.74, C∞: from 63.5 to 65.5). All present results suggest that longan seeds show the potential to prepare resistant starch applied in food industry.

Formation and structural dynamics of Lotus seed starch-linolenic acid complexes under high pressure microfluidization and their evolution during simulated gastrointestinal digestion

Linolenic acid (ALA) can promote the production of intestinal short-chain fatty acids and the growth of beneficial bacteria. However, its polyunsaturated nature makes it prone to oxidation. To address this, lotus seed starch (LS) was used as a carrier to form LS-ALA complexes via dynamic high-pressure microfluidization (DHPM) at 180 MPa. The resulting complex exhibited high crystallinity and thermal stability, with 14.84 ± 0.16 % ALA content. This complexation reduced starch's short-range order and increased its solubility at room temperature, with 17.42 ± 0.49 % being resistant starch. Importantly, during in vitro digestion, the complex's crystal form remained unchanged, the ALA content in the remaining complex increased, and the carboxyl peak of the fatty acid was more obvious after digestion, indicating that ALA was protected during this process. These findings reveal the interaction mechanisms between ALA and starch, establish a basis for efficient LS-ALA complex preparation, and support further interaction studies.

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

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

Structural and physicochemical properties of debranched lotus seed starch treated with high hydrostatic pressure

Lotus seeds represent a significant economic crop and are abundant in starch. To further enhance their application value, this study investigates the structural characteristics of lotus seed starch (LS) under the combined influence of pullulanase and high hydrostatic pressure (HHP). Pullulanase increased amylose content from 39.80 % to 72.26 %, and HHP increased amylose content further. LS crystals changed from C-type to B-type, and the ordered structure of LS was destroyed by enzymatic hydrolysis, and amylose single helix and partial double helix structure were formed. At low concentration, lotus seed amylose single helix tends to form amylose double helix structure with itself. At high concentrations, they tend to aggregate, forming a network structure with large surface area and loose order. HHP destroys the double helix structure of amylose, resulting in the decrease of starch crystallinity. These findings provide new insights into improving the processing properties and application range of lotus seed starch.

Comparative effects of four types of resistant starch on the techno-functional properties of low-fat meat emulsions

The behavior of resistant starch (RS) in meat matrix depends largely on its type. Hence, the comparative impacts of high amylose corn starch (RS2), retrograded starch (RS3), acetylated starch (RS4) and high amylose-lauric acid complex (RS5) on water-fat binding capacities, texture, color and microstructure of low-fat meat emulsions were investigated. Four types of RS improved water retention, emulsion stability, textural properties and brightness of low-fat meat emulsions, displaying even better potential than inulin (positive control). Compared with inulin, RS2 ∼ RS5 induced the transition from free water to immobilized water, increased storage modulus G' (by 21.90 %, 38.13 %, 55.73 % and 45.92 %, respectively), hydrophobic interactions (by 36.03 %, 60.84 %, 44.40 % and 48.04 %, respectively), disulfide bonds and β-sheet, which promoted the formation of tight protein gel networks. Notably, physical or chemical modified RS (RS3, RS4, RS5) displayed preferable and more similar water-fat binding properties, making them more promising for personalized application in low-fat functional meat products.

Dynamic/static pressure-induced copolymerization and property changes of lotus seed starch with chlorogenic acid

Pressure promotes the formation of starch-polyphenol complexes, but their classification and properties are still unclear. This study aimed to elucidate the effects of dynamic high-pressure homogenization (10-50 MPa) and static hydrostatic pressure (100-500 MPa) on the copolymerization behavior and properties of lotus seed starch (LS)-endogenous polyphenol chlorogenic acid (CA) complexes. The results showed that both pressures induced LS-CA to form stable inclusion-type complexes and easily destructible noninclusion-type complexes. Increased pressure promoted the formation of inclusion-type complexes, with dynamic pressure having a particularly strong effect. However, noninclusion-type complexes began breaking down at 20 MPa under dynamic pressure and 300 MPa under static pressure. Inclusion-type complexes primarily improve starch ordering, and noninclusion-type complexes enhance water holding capacity, but excessive proportions of either type affect pasting performance. These findings offer insights into transforming specific starch structures through small molecular components and provide a theoretical basis for controlling functional starch product processing.

Physicochemical characterization and in vitro digestibility of resistant starch from corn starch sugar residue

This study sought to investigate the thermal stability and digestibility of corn starch sugar residue resistant starch (CSSR-RS) through comparative analysis of the physicochemical properties and structural characteristics among CSSR-RS, high-amylose corn starch (HS), and normal corn starch (NS). CSSR-RS contained 51.76 % resistant starch (RS), with 42.6 % remaining after high-temperature treatment, which was significantly higher than HS, demonstrating strong resistance to gelatinization. CSSR-RS is characterized by highly ordered aggregation of small molecules with a C-type crystalline structure, and irregular granular structures with wrinkled surfaces. Compared with NS and HS, the short-range and long-range order of CSSR-RS were significantly higher, indicating excellent thermal stability. In vitro simulated digestion revealed that the total hydrolysis rate of CSSR-RS was significantly lower than those of NS and HS, and the residual digesta of CSSR-RS also showed better resistance to digestion than HS. CSSR-RS exhibited significant development prospects in healthy food.

Changes in Functional Properties and In Vitro Digestibility of Black Tartary Buckwheat Starch by Autoclaving Combination with Pullulanase Treatment

The processing properties of resistant starch (RS) and its digestion remain unclear, despite the widespread use of autoclaving combined with debranching in its preparation. In this study, the physicochemical, rheological and digestibility properties of autoclaving modified starch (ACB), autoclaving-pullulanase modified starch (ACPB) and native black Tartary buckwheat starch (NB) were compared and investigated. The molecular weight and polydispersity index of modified starch was in the range of 0.15 × 104~1.90 × 104 KDa and 1.88~2.82, respectively. In addition, the SEM results showed that both modifications influenced the morphological characteristics of the NB particles, and their particles tended to be larger in size. Autoclaving and its combination with pullulanase significantly increased the short-range ordered degree, resistant starch yield and water- and oil-absorption capacities, and decreased the syneresis properties with repeated freezing/thawing cycles. Moreover, rheological analysis showed that both ACB and ACPB exhibited shear-thinning behavior and lower gel elasticity as revealed by the power law model and steady-state scan. The degradation of starch chains weakened the interaction of starch molecular chains and thus changed the gel network structure. The in vitro digestion experiments demonstrated that ACB and ACPB exhibited greater resistance to enzymatic digestion compared to the control, NB. Notably, the addition of pullulanase inhibited the hydrolysis of the ACB samples, and ACPB showed greater resistance against enzymatic hydrolysis. This study reveals the effects of autoclaving combined with debranching on the processing properties and functional characteristics of black Tartary buckwheat starch.

Physicochemical, enzymatic and fermentation modifications improve resistant starch levels and prebiotic properties of porang (Amorphophallus oncophyllus) flour

Porang tubers (Amorphophallus oncophyllus) are one of the Araceae family plants, which naturally contain resistant starch (RS). The RS is able to provide health impacts such as reducing the glycaemic index (GI), preventing the formation of gallstones and cardiovascular disease, and increasing mineral absorption. This research aims to improve the RS and prebiotic properties of porang flour through physical, chemical, enzymatic and microbiological modifications. Research methods include modification with physical treatment of autoclaving‐cooling one and two cycles (AC‐1S and AC‐2S), microwave‐cooling (MWC), heat moisture treatment (HMT), annealing (ANN), chemical treatment with acid hydrolysis (HA), enzymatic treatment with pullulanase debranching (DP) and microbiological treatment with combined heating and cooling fermentation (FAC). The results showed that physical, chemical, enzymatic and fermentation modification techniques increased the characteristics of RS and the prebiotic properties of porang flour. The best modification method for porang flour was obtained in the DP treatment with the morphological characteristics of sharp‐surfaced granules, total starch 39.81%, amylose content 3.73%, amylopectin content 36.08%, reducing sugar content 16.31%, power digestibility 43.81%, very rapidly digestible starch (VRDS) 8.59%, rapidly digestible starch (RDS) 11.08%, slowly digestible starch (SDS) 23.60%, RS 56.73%, resistance to gastric acid 98.60%, lactic acid bacteria (LAB) viability 11.87 log cfu/ml, prebiotic effect 3.07, prebiotic index 2.46 and prebiotic activity 1.77.

Effect of maturity on the drying characteristics of lotus seed and molecular structure, gelation and digestive properties of its starch

Maturity and drying treatment are important factors affecting the processing characteristics of lotus seeds and its starch. This study aimed to investigate the effect of maturity (from low to high-M-1, M-2, M-3, M-4) on far-infrared drying kinetics of lotus seeds, and on the variation of structure, gelation and digestive properties of lotus seed starch (LSS) before and after drying. As the maturity increased, the drying time reduced from 5.8 to 1.0 h. The reduction of drying time was correlated with the decrease of initial moisture content, the increase of water freedom and the destruction of tissue structure during ripening. The increased maturity and drying process altered the multiscale structure of LSS, including an increase in amylose content, disruption of the short-range structure, and a decrease in relative crystallinity and molecular weight. The viscosity, pasting temperature and enthalpy of LSS decreased during ripening, and drying treatment caused the further decrease. The digestibility of LSS increased during ripening and drying. Lotus seeds at M-4 would be optimal for obtaining shorter drying time, lower pasting temperature and enthalpy, and higher digestibility. This study provided theoretical guidance for achieving effective drying process and screening LSS with suitable processing properties through maturity sorting.

Dietary fiber-rich Lentinula edodes stems influence the structure and in vitro digestibility of low-moisture extruded maize starches

Low-moisture extrusion (LME) can be used to improve the utilization of dietary fiber-rich Lentinula edodes stems (LES). The incorporation of dietary fiber can affect heat-induced interactions of starch molecules, which are critical for modifying starch characteristics via LME. In this work, a blend of LES and maize starch was extruded into a product at low moisture (30 %, w/v). The structure, physicochemical properties, and in vitro digestibility of extruded maize starches were investigated at different LES levels. The results showed that low levels (<7 %) of LES increased the crystallinity of LME-produced starch, while high levels (>7 %) did not. Because of the LES's soluble to insoluble dietary fiber ratios, the increased crystallinity of LES-added starch led to greater molecular ordering and the formation of an elastic gel after LME. At a suitable LES level (~3 %), highly crystallized starches were resistant to enzymolysis and had a high proportion of resistant starch. The obtained findings would contribute to a better understanding of how dietary fiber-rich LES affects starch extrusion and provide an alternative use for boosting the value of LES by-products.

Understanding the multiscale structure and in vitro digestibility changes of corn starch-ferulic acid complexes induced by high hydrostatic pressure

High hydrostatic pressure (HHP) was used to synthesize corn starch (CS) and ferulic acid (FA) complex (CS-FA). Its effects on the structure of the complex at multiple scales and its digestibility were examined. The results demonstrated that HHP significantly influenced the digestibility of the CS-FA complex, decreasing the content of rapidly digestible starch (RDS) while increasing slowly digestible starch (SDS) and resistant starch (RS). Notably, the combined SDS and RS content in the HHP-treated CS-FA complex with 2.0 % FA addition (38.13 %) was significantly higher (p < 0.05) than those in the CS-FA complex without HHP treatment (29.21 %) and pure CS (21.72 %). The results indicated that HHP treatment reduced the enthalpy change (ΔH), number of short-range order structures, and relative crystallinity (RC) while increasing the average particle size of these CS-FA complexes. This treatment also increased the proportion of amorphous starch regions and the degree of agglomeration between the starch and FA. HHP treatment-induced CS-FA complexes exhibited a denser fractal structure and higher short-range order, affecting the interaction sites between the starch and digestive enzymes. These findings suggest the potential application of HHP treatment and FA in modulating the postprandial glycemic response to starchy food.

High-Resistant Starch Based on Amylopectin Cluster via Extrusion: From the Perspective of Chain-Length Distribution and Structural Formation

Resistant starch (RS) has the advantage of reshaping gut microbiota for human metabolism and health, like glycemic control, weight loss, etc. Among them, RS3 prepared from pure starch is green and safe, but it is hard to achieve structural control. Here, we regulate the crystal structure of starch with different chain-length distributions (CLDs) via extrusion at low/high shearing levels. The change in CLDs in extruded starch was obtained, and their effects on the fine structure (Dm, dBragg, dLorentz, degree of order and double helix, degree of crystal) of RS and its physicochemical properties were investigated by SAXS, FTIR, XRD and 13C NMR analyses. The results showed that the RS content under a 250 r/min extrusion condition was the highest at 61.52%. Furthermore, the crystalline system induced by high amylopectin (amylose ≤ 4.78%) and a small amount of amylose (amylose ≥ 27.97%) was favorable for obtaining a high content of RS3-modified products under the extruding environment. The control of the moderate proportion of the A chains (DP 6-12) in the starch matrix was beneficial to the formation of RS.

Comparison of anti-allergic activities of different types of lotus seed resistant starch in OVA-induced mouse model

Currently, evidence from observational studies suggests dietary fiber intake may be associated with decreased risk of food allergy. As a type of dietary fiber, resistant starch was also widely reported to possess anti-allergic properties. However, there is a relative paucity of studies assessing the influence of resistant starch types on their anti-allergic activity and its possible underlying mechanisms. In the current study, the anti-allergic effects of RS3-type (retrograded starch), RS4-type (chemically modified starch, cross-bonded), and RS5-type (starch-palmitic acid complex) of lotus seed resistant starch were evaluated in the OVA (100 mg/kg)-induced food allergic mice model. The results showed that oral administration of RS3 or RS4 lotus seed resistant starch (0.3 g/100 g b.w.) for 25 days significantly improved adverse symptoms of food allergy such as weight loss, increases in allergy symptom score and diarrhea rate; with significant reduction of serum specific antibody IgE, TNF-α, IL-4 levels and improved Th1/Th2 balance being observed. The mechanism may involve the regulation of lotus seed resistant starch on intestinal flora and the metabolites short-chain fatty acids and bile acids. Taken together, the findings may enhance understanding towards ameliorative effects of resistant starch on food allergy, and offer valuable insights for the exploration of novel anti-allergic bioactive compounds.

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.

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

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

Effect of structural characteristics of resistant starch prepared by various methods on microbial community and fermentative products

Resistant starch (RS) has been extensively studied because of its beneficial effects on gut microbiota. In this study, four RSs obtained through various preparation processes were utilized for in vitro fermentation, and their structural characteristics before and after fermentation were determined using chromatography, Fourier infrared spectroscopy, and scanning electron microscopy (SEM). It was observed that these RSs can be classified into two categories based on their fermentation and structural features. The autoclaving RS (ARS) and extruding RS (ERS) were classified as Class I Microbiome Community (MC-I), characterized by a higher proportion of butyrate and its producers, including unclassified_g_Megasphaera and Megasphaera elsdenii. While microwaving RS (MRS) and ultrasound RS (URS) belonged to Class II Microbiome Community (MC-II), marked by a higher proportion of acetate and its producer, Bifidobacterium pseudocatenulatum DSM 20438. MC-I had a lower molecular weight, shorter chain length, more chains with degree of polymerization (DP) 36-100, and a more ordered structure than MC-II. Furthermore, SEM observations revealed distinct degradation patterns between MC-I and MC-II, which may be attributed to their surface structural characteristics. These findings imply that the preparation methods employed for RS can determine its multilevel structural characteristics, and consequently influence its physiological properties.

Evaluation of Quality Properties of Brown Tigernut (Cyperus esculentus L.) Tubers from Six Major Growing Regions of China: A New Source of Vegetable Oil and Starch

Tigernut has been recognized as a promising resource for edible oil and starch. However, the research on the quality characteristics of tigernut from different regions is lagging behind, which limits the application of tigernut in food industry. Tigernut tubers were obtained from six major growing regions in China, and the physicochemical properties of their main components, oil and starch, were characterized. Tigernut tubers from Baoshan contained the most oil (30.12%), which contained the most β-carotene (130.4 µg/100 g oil) due to high average annual temperature. Gas chromatography analysis and fingerprint analysis results indicated that tigernut oil (TNO) consists of seven fatty acids, of which oleic acid is the major component. Changchun TNO contained the least total tocopherols (6.04 mg/100 g oil) due to low average annual temperature. Tigernut tubers from Chifeng (CF) contained the most starch (34.85%) due to the large diurnal temperature range. Xingtai starch contained the most amylose (28.4%). Shijiazhuang starch showed the highest crystallinity (19.5%). Anyang starch had the highest pasting temperature (76.0°C). CF starch demonstrated superior freeze-thaw stability (syneresis: 50%) due to low mean annual precipitation. The results could be further applied to support tigernut industries and relevant researchers that looks for geographical origin discrimination and improvements on tigernut quality, with unique physicochemical and technological properties.

Extrusion as pretreatment for complexation of high-amylose starch with glycerin monostearin: Dependence on the guest molecule

Low-moisture extrusion (LME) can modify starch structures and enrich their functionality. These LME-made starches may efficiently form inclusion complexes (ICs) with hydrophobic guest molecules, which is profoundly impacted by the guest molecule concentration. In this work, the influence of glycerin monostearin (GMS) concentration on the structure and in vitro digestibility of pre-extruded starch-GMS complexes was investigated. The results showed that LME pretreatment increased the complex index of high-amylose starch with GMS by 13 %. The appropriate GMS concentrations produced ICs with high crystallinity and excellent thermostability. The presence of IC retarded amylose retrogradation and dominated bound water in starches. In addition, highly crystallized ICs were resistant to enzymolysis and had a higher proportion of resistant starch. The acquired knowledge would provide a better understanding of the LME-modified starch and GMS concentration-regulated IC formation.

Cross-linked modifications of starches from colored highland barley and their characterizations, digestibility, and lipolysis inhibitory abilities in vitro

To promote the stability and functionality of native starch from colored highland barley (CHBS), the cross-linked modifications with sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) and citric acid were conducted to prepare CHB resistant starches (CHRSs), whose physicochemical characteristics, digestibility, and lipolysis inhibitory potential were also assessed. Results showed that the resistant starch amounts in CHBS were significantly increased after cross-linking and differed slightly among CHRSs. Citric acid modification of CHBS resulted in significantly higher amylose amounts, solubilities, swelling powers, and water-binding capacities than those under STMP/STPP modification within the cultivars (p < 0.05), with their crystalline patterns of A-type (white and blue) and CB-type (black). STMP/STPP modified CHBS exhibited higher degrees of crystalline regions with B-type crystalline patterns. Due to the differences in structural properties and structure-based morphology, STMP/STPP cross-linked CHBS showed lower digestibility and citric acid cross-linked CHBS exhibited higher lipolysis inhibitory activities. Besides, the cross-linked modifications demonstrated more enhancements in functionalities of starches from white and blue cultivars than black cultivar.

Shortening growth year improves functional features of kudzu starch by tailoring its multi-scale structure

Kudzu is usually consumed at different growth years, yet the influences of growth years on its multi-scale structures and physicochemical features have not been fully disclosed. In this study, those influences occurred on kudzu starches (KS2, KS10, KS30 and KS50, isolated using precipitation method) were investigated. The granules size, crystallinity, short-range ordered structure, amylose content, intermediate and longer amylose chains reduced but the average thickness of crystalline lamella increased as the rise of growth years. KS2 had lower content of defective crystal structure and higher content of near-perfect crystal structure. Those signified that bulk density of molecules packing into starch substrate was higher for KS2, which was not beneficial for water molecules and enzymes entering into starch granules and thus elevated pasting temperature and reduced digestion rate. Besides, reduced proportions of defective ordered structures and enhanced lipid-amylose complex also reduced digestion rate. Both the peak and breakdown viscosity were in order of KS2 > KS10 > KS30 ≈ KS50. And KS2, KS10, and KS30 exhibited enhanced retrogradation tendency during cooling than KS50 as evidenced by the relative higher setback viscosity. Those results are favor for rational screen and usage of kudzu starch resources with different growth years for food applications.

Non-Traditional Starches, Their Properties, and Applications

This review paper focuses on the recent advancements in the large-scale and laboratory-scale isolation, modification, and characterization of novel starches from accessible botanical sources and food wastes. When creating a new starch product, one should consider the different physicochemical changes that may occur. These changes include the course of gelatinization, the formation of starch-lipids and starch-protein complexes, and the origin of resistant starch (RS). This paper informs about the properties of individual starches, including their chemical structure, the size and crystallinity of starch granules, their thermal and pasting properties, their swelling power, and their digestibility; in particular, small starch granules showed unique properties. They can be utilized as fat substitutes in frozen desserts or mayonnaises, in custard due to their smooth texture, in non-food applications in biodegradable plastics, or as adsorbents. The low onset temperature of gelatinization (detected by DSC in acorn starch) is associated with the costs of the industrial processes in terms of energy and time. Starch plays a crucial role in the food industry as a thickening agent. Starches obtained from ulluco, winter squash, bean, pumpkin, quinoa, and sweet potato demonstrate a high peak viscosity (PV), while waxy rice and ginger starches have a low PV. The other analytical methods in the paper include laser diffraction, X-ray diffraction, FTIR, Raman, and NMR spectroscopies. Native, "clean-label" starches from new sources could replace chemically modified starches due to their properties being similar to common commercially modified ones. Human populations, especially in developed countries, suffer from obesity and civilization diseases, a reduction in which would be possible with the help of low-digestible starches. Starch with a high RS content was discovered in gelatinized lily (>50%) and unripe plantains (>25%), while cooked lily starch retained low levels of rapidly digestible starch (20%). Starch from gorgon nut processed at high temperatures has a high proportion of slowly digestible starch. Therefore, one can include these types of starches in a nutritious diet. Interesting industrial materials based on non-traditional starches include biodegradable composites, edible films, and nanomaterials.

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.

Structural characterization of different starch-fatty acid complexes and their effects on human intestinal microflora

Resistant starch type 5 (RS5), a starch-lipid complex, exhibited potential health benefits in blood glucose and insulin control due to the low digestibility. The effects of the crystalline structure of starch and chain length of fatty acid on the structure, in vitro digestibility, and fermentation ability in RS5 were investigated by compounding (maize, rice, wheat, potato, cassava, lotus, and ginkgo) of different debranched starches with 12-18C fatty acid (lauric, myristic, palmitic, and stearic acids), respectively. The complex showed a V-type structure, formed by lotus and ginkgo debranched starches, and fatty acid exhibited a higher short-range order and crystallinity, and lower in vitro digestibility than others due to the neat interior structure of more linear glucan chains. Furthermore, a fatty acid with 12C (lauric acid)-debranched starches complexes had the highest complex index among all complexes, which might be attributed to the activation energy required for complex formation increased with the lengthening of the lipid carbon chain. Therefore, the lotus starch-lauric acid complex (LS12) exhibited remarkable ability in intestinal flora fermentation to produce short-chain fatty acid (SCFAs), reducing intestinal pH, and creating a favorable environment for beneficial bacteria.

The research advance of resistant starch: structural characteristics, modification method, immunomodulatory function, and its delivery systems application

Resistant starch, also known as anti-digestion enzymatic starch, which cannot be digested or absorbed in the human small intestine. It can be fermented in the large intestine into short-chain fatty acids (SCFAs) and metabolites, which are advantageous to the human body. Starches can classify as rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), which possess high thermal stability, low water holding capacity, and emulsification characteristics. Resistant starch has excellent physiological functions such as stabilizing postprandial blood glucose levels, preventing type II diabetes, preventing intestinal inflammation, and regulating gut microbiota phenotype. It is extensively utilized in food processing, delivery system construction, and Pickering emulsion due to its processing properties. The resistant starches, with their higher resistance to enzymatic hydrolysis, support their suitability as a potential drug carrier. Therefore, this review focuses on resistant starch with structural features, modification characteristics, immunomodulatory functions, and delivery system applications. The objective was to provide theoretical guidance for applying of resistant starch to food health related industries.

Unveiling the retrogradation mechanism of a novel high amylose content starch-Pouteria campechiana seed

The research of starch retrogradation have been attracting interest. Thereby, the long-term retrogradation mechanism (0-21 days) of Pouteria campechiana seed starch (PCSS) was investigated. The results showed that crystal type was changed from A- to B + V-type during retrogradation. The retrogradation PCSS (RPCSS) exhibited faster retrogradation rate and more compact internal ultra-structure compared to rice, wheat and maize starch. Pearson correlation indicated that, as retrogradation days increased, values of α-1,4-glycosidic bond, A chains, double helix, V-type polymorphism, Mw, relative crystallinity (Rc) and short-range order gradually significantly increased, and B1 chains, B3 + chains values gradually significantly dropped (p < 0.05). These inferred an increasing peak temperature and compactness of morphology with increasing retrogradation days. Compared to native starch, RPCSS α-1.4-glycosidic bond was increased, which indicated that its quick molecules degradation including decreased Mw, B3 + chains, Rc, semicrystalline order, and ΔH. These might provide a theoretical direction for preparation of starch-basis food.

Metabolism of resistant starch RS3 administered in combination with Lactiplantibacillus plantarum strain 84-3 by human gut microbiota in simulated fermentation experiments in vitro and in a rat model

This study aimed to investigate the metabolic and population responses of gut microbiota to resistant starch (RS3) in the presence of exogenous Lactiplantibacillus plantarum strain 84-3 (Lp84-3) in vitro and in vivo. Lp84-3 promoted acetate, propionate, and butyrate production from RS3 by gut microbiota and increased Lactobacillus and Blautia contents in vitro. Furthermore, in the presence of Lp84-3, starch granules presented a "dot-by-hole" fermentation pattern. Administration of Lp84-3 with RS3 increased the level of SCFA-producing Faecalibaculum, Parabacteroides, Alistipes, and Anaeroplasma in the faeces of rates, with Lactobacillus and Akkermansia representing the key genera that significantly promoted SCFAs, especially propionate and butyrate. Lp84-3 with RS3 promoted genes related to tryptophan synthase (EC 4.2.1.20) and beta-glucosidase (EC 3.2.1.21) in faecal bacteria. Our findings highlight the ability of Lp84-3 to enhance RS3 degradation, possibly by promoting SCFA-producing bacteria, and indicate that Lp84-3 could be a potential probiotic with a beneficial effect on gut microbiota.

Structure and physicochemical properties of low digestible Euryale ferox Salisb. seed starch

BACKGROUND

Euryale ferox Salisb. is widely grown in China and Southeast Asia as a grain crop and medicinal plant. The composition, morphology, structure, physicochemical properties, thermal properties, and in vitro digestibility of North Euryale ferox seeds starch (NEFS), hybrid Euryale ferox seeds starch (HEFS), and South Euryale ferox seeds starch (SEFS) were studied.

RESULT

Of the varieties that were studied, the amylose content of NEFS (23.03%) was the highest. Starch granules of each variety were smooth, sharp, small, and had an average diameter of 2 μm. All three varieties were A-type crystals with crystallinity ranging from 26.42% to 28.17%. The degree of double helix and the short-range order ranged from 1.9006 to 2.5324 and 1.4294 to 1.6006, respectively. The high proportion of C1 region in NEFS (17.74%) and HEFS (17.66%) were found. Thermodynamic properties in North Euryale ferox seeds included the highest onset temperature (T_o ) (71.43 °C), peak temperature (T_p ) (76.60 °C), conclusion temperature (T_c ) (82.77 °C), enthalpy of gelatinization (ΔH) (12.64 J g^-1 ), and peak viscosity (1514 mPa·s). All three varieties maintained a low level of in vitro digestibility, with the highest resistant starch (RS) content (29.57%), the lowest rapidly digestible starch (RDS) content (27.07%), and the slowest hydrolysis kinetic constant (0.0303) in NEFS.

CONCLUSION

The results revealed that the low digestibility of NEFS was attributable to compact granules, high crystallinity, high degree of order, and strong thermal stability. These digestive, physicochemical, and thermodynamic properties provide information for the future application of Euryale ferox seed starch in the food industry. © 2022 Society of Chemical Industry.

Evaluation of cooking characteristics, textural, structural and bioactive properties of button mushroom and chickpea starch enriched noodles

The present study was conducted out to develop nutritionally enriched noodles by supplementing wheat flour with mushroom and chickpea starch at different concentrations and its effect on physico-chemical, bioactive, cooking, microbial and sensory properties, morphological and textural properties has been investigated. The prepared noodles contained high levels of protein, and low levels of carbohydrate, energy with the incorporation of mushroom flour and chickpea starch concentration. The lightness (L*) (71.79-53.84) decreased and yellowness (b*) (19.33-31.36) and redness (a*) (1.91-5.35) increased with the incorporation of mushroom flour and chickpea starch. The optimum cooking time decreased while as the water absorption capacity and cooking loss increased with increase in mushroom flour and chickpea starch concentration. The microstructure study and textural properties depicted the clear picture of protein network, with smooth outer surface, and the decrease in hardness with increased concentration of mushroom flour and chickpea starch. XRD and DSC results revealed that the prepared noodles contained more complete crystallites and high fraction of crystalline region and the linear increase in the gelatinization temperature with increase in composite flour concentration. The microbial analysis of noodles showed the decrease in microbial growth with the incorporation of composite flour.

Structural Properties of Lotus Seed Starch Nanocrystals Prepared Using Ultrasonic-Assisted Acid Hydrolysis

This study provides a novel method of preparing lotus seed starch nanocrystals (LS-SNCs) using acid hydrolysis combined with ultrasonic-assisted acid hydrolysis (U-LS-SNCs) and evaluates the structural characteristics of starch nanocrystals using scanning electron microscopy; analysis of particle size, molecular weight, and X-ray diffraction patterns; and FT-IR spectroscopy. The results showed that the preparation time of U-LS-SNCs could be reduced to 2 days less than that for LS-SNCs. The smallest particle size and molecular weight were obtained after a 30 min treatment with 200 W of ultrasonic power and 5 days of acid hydrolysis. The particle size was 147 nm, the weight-average molecular weight was 3.42 × 10⁴ Da, and the number-average molecular weight was 1.59 × 10⁴ Da. When the applied ultrasonic power was 150 W for 30 min and acid hydrolysis was applied for 3 days, the highest relative crystallinity of the starch nanocrystals was 52.8%. The modified nanocrystals can be more widely used in various applications such as food-packaging materials, fillers, pharmaceuticals, etc.

Different multi-scale structural features of oat resistant starch prepared by ultrasound combined enzymatic hydrolysis affect its digestive properties

In this research, oat resistant starch (ORS) was prepared by autoclaving-retrogradation cycle (ORS-A), enzymatic hydrolysis (ORS-B), and ultrasound combined enzymatic hydrolysis (ORS-C). Differences in their structural features, physicochemical properties and digestive properties were studied. Results of particle size distribution, XRD, DSC, FTIR, SEM and in vitro digestion showed that ORS-C was a B + C-crystal, and ORS-C had a larger particle size, the smallest span value, the highest relative crystallinity, the most ordered and stable double helix structure, the roughest surface shape and strongest digestion resistance compared to ORS-A and ORS-B. Correlation analysis revealed that the digestion resistance of ORS-C was strongly positively correlated with RS content, amylose content, relative crystallinity and absorption peak intensity ratio of 1047/1022 cm^-1 (R_1047/1022), and weakly positively correlated with average particle size. These results provided theoretical support for the application of ORS-C with strong digestion resistance prepared by ultrasound combined enzymatic hydrolysis in the low GI food application.

Effects of different rapid cooling temperatures and annealing on functional properties of starch straws after thermoplastic extrusion

To improve the performance of starch straws in rapidly cooling and annealing procedure of thermoplastic extrusion, control straw was prepared through slowly cooling at 25 °C, and starch straw was prepared through regulating different rapid cooling temperatures including 20 °C, 5 °C, -10 °C and -20 °C. The results indicated that control straw exhibited a homogeneous state, while starch straws treated by rapid cooling displayed like a wash-board structure. Compared to control straw, the ratio of the absorption peak intensity of 1047 and 1022 cm^-1 increased from 1.050 to 1.455 as cooling temperatures decreased from 25 °C to -20 °C, indicating short-range order of the double helix structure significantly enhanced. The relative crystallinities of starch straws increased from 12.01 % to 16.58 %. The maximum bending force value (60.92 N) of starch straws cooled at -20 °C was significantly higher than that (46.14 N) of control straw. Conversely, the modulus of elasticity in bending values (4.21-16.43 N/cm) of rapid cooling-treated straws were significantly lower than that (48.42 N/cm) of control straw. Water absorption of rapid cooling-treated straws were lower than that of control straw, indicating the hydrophobicity property of starch straws significantly improved.

Ultrasonication-mediated formation of V-type lotus seed starch for subsequent complexation with butyric acid

V-type starches comprise single helical structures that can be complexed with other small hydrophobic molecules. The development of the subtypes of these assembled V-conformations is dependent on the helical state of the amylose chains during complexation, which is influenced by the pretreatment employed. In this work, the effect of preultrasonication on the structure and in vitro digestibility of preformed V-type lotus seed starch (VLS) and its potential for complexing with butyric acid (BA), was investigated. The results showed that ultrasound pretreatment did not affect the crystallographic pattern of the V₆-type VLS. The optimal ultrasonic intensities increased the crystallinity and molecular ordering of the VLSs. With an increase in the preultrasonication power, the pores on the VLS gel surface decreased in size and were more densely distributed. The VLSs formed at 360 W were less vulnerable to digestive enzymes than their untreated counterparts. Additionally, their highly porous structures could accommodate numerous BA molecules, and thus generated inclusion complexes via hydrophobic interactions. These findings would provide valuable insights into the ultrasonication-mediated formation of VLSs and suggest their potential application as carriers for the delivery of BA molecules to the gut.

Effect of resistant starch types as a prebiotic

Since the role of intestinal microbiota in metabolism was understood, the importance of dietary components such as fibres and prebiotics, which affect the modulation of microbiota, has been increasing day by day. While all prebiotic components are considered dietary fibre, not every dietary fibre is considered a prebiotic. While fructooligosaccharides, galactooligosaccharides, inulin, and galactans are considered prebiotics, other fermentable carbohydrates are considered candidate prebiotic components based on in vitro and preclinical studies. Resistant starch, one of such carbohydrates, is considered a potential prebiotic component when it is made resistant to digestion naturally or chemically. In this review, both in vitro and in vivo studies in which the prebiotic capacity of type II, type III, and type IV resistant starch isolated from food and produced commercially was assessed were analyzed. According to the results of current studies, certain types of resistant starch are thought to have a high prebiotic capacity, and they may be candidate prebiotic components although positive results have not been achieved in all studies. KEY POINTS: • Resistant starch is undigested in the small intestine and is fermented in the large intestine. • Resistant starch fermentation positively affects the growth of Bifidobacterium and Lactobacillus. • Resistant starch can be considered a prebiotic ingredient.

Study on structural characteristics, physicochemical properties, and in vitro digestibility of Kudzu-resistant starch prepared by different methods

Three different methods, including autoclaving, autoclaving-debranching, and purification, were used to prepare Kudzu-resistant starch (KRS) from Kudzu starch (KS). The physicochemical properties, such as thermodynamic properties, pasting properties, solubility, swelling, and coagulability, as well as the in vitro digestive characteristics of the three kinds of KRS were studied. The results showed that the morphology of starch granules of KRS prepared by autoclave, autoclave enzymatic hydrolysis, and purification methods was changed and the relative crystallinity was significantly decreased compared with the original starch. X-ray diffraction (XRD) showed that KRS exists in the form of C and C+V crystalline form. There was a significant increase in the pasting temperature and a remarkable decrease in the peak viscosity and the expansion degree of the KRS prepared by all three methods. The solubility of the resistant starch (RS) obtained by autoclaving-debranching and that by purification were both increased compared to that of native KS, while the solubility of the RS obtained by autoclaving was decreased. Meanwhile, the retrogradation of the three RS was also improved to varying degrees. The contents of RS in the samples were: P-KRS (71%) > DA-KRS (43%) > A-KRS (42%) > KS (9%). Simulated human in vitro digestion experiments showed that RS has stronger antidigestibility properties than native starch. Among them, the RS prepared by the purification method has stronger antidigestive properties, and it is predicted that it may have a better potential value in regulating blood glucose. These results indicated that the processing properties of KRS, especially the digestibility, are significantly improved and can be used as a new functional food ingredient, which deserves thorough study.

Effects of Heat-Moisture Treatment on the Digestibility and Physicochemical Properties of Waxy and Normal Potato Starches

Heat-moisture treatment (HMT) is a safe, environmentally friendly starch modification method that reduces the digestibility of starch and changes its physicochemical properties while maintaining its granular state. Normal potato starch (NPS) and waxy potato starch (WPS) were subjected to HMT at different temperatures. Due to erosion by high-temperature water vapor, both starches developed indentations and cracks after HMT. Changes were not evident in the amylose content since the interaction between the starch molecules affected the complexation of amylose and iodine. HMT increased pasting temperature of NPS from 64.37 °C to 91.25 °C and WPS from 68.06 °C to 74.44 °C. The peak viscosity of NPS decreased from 504 BU to 105 BU and WPS decreased from 384 BU to 334 BU. The crystallinity of NPS decreased from 33.0% to 24.6% and WPS decreased from 35.4% to 29.5%. While the enthalpy values of the NPS declined from 15.74 (J/g) to 6.75 (J/g) and WPS declined from 14.68 (J/g) to 8.31 (J/g) at 120 °C. The solubility and swelling power of NPS decreased while that of WPS increased at 95 °C. Due to the lack of amylose in WPS, at the same HMT processing temperature, the reduction in peak viscosity of treated WPS compared to that of native starch was smaller than that of NPS. The resistant starch (RS) content of NPS after HMT at 120 °C was 73.0%. The slowly digestible starch (SDS) content of WPS after HMT at 110 °C was 37.6%.

Effect of Pullulanase Debranching Time Combined with Autoclaving on the Structural, Physicochemical Properties, and In Vitro Digestibility of Purple Sweet Potato Starch

The effects of pullulanase debranching combined with autoclaving (PDA) at various debranching times (0 h, 5 h, 10 h, 15 h, 20 h, and 25 h) and 121 °C/20 min of autoclave treatment on the structural and physicochemical characteristics of purple sweet potato (Jinshu No.17) starch were investigated. The results indicated that the native starch (NS) was polygonal, round, and bell-shaped with smooth surfaces. After debranching treatment, the surface of the starch samples became rough and irregular. The molecular weight became smaller after treatments. X-ray diffraction C-type pattern was transformed into a B-type structure in treated samples with increased relative crystallinity. ¹³C NMR indicated an increased propensity for double helix formation and new shift at C1, 3, 5 region compared to NS. The apparent amylose content was 21.53% in the NS. As the swelling power decreased, the percentage of soluble solids increased and different thermal properties were observed. A higher yield of the resistant starch (RS) was observed in all treated starch except PDA 25 h. The findings of our study reveal that a combination of pullulanase debranching time (15 h) and autoclaving (121 °C for 20 min) is a great technique that can be used to produce a higher amount of resistant starch in the Jinshu No.17 starch.

Interaction between dietary fiber and bifidobacteria in promoting intestinal health

Bifidobacteria are considered as probiotics due to their role in promoting intestinal health, including regulating intestinal flora, controlling glycolipid metabolism, anti-colitis effects. Dietary fiber is considered as prebiotic favoring gut health. It also can be used as carbon source to support the growth and colonization of probiotics like bifidobacteria. However, because of genetic diversity, different bifidobacterial species differ in their ability to utilize dietary fiber. Meanwhile, dietary fiber with different structural properties has different effects on the bifidobacteria proliferation. The interaction between dietary fiber and bifidobacteria will consequently lead to a synergistic or antagonistic function in promoting intestinal health, therefore affecting the application of combined use of dietary fiber and bifidobacteria. In this case, we summarize the biological function of bifidobacteria, and their interaction with different dietary fiber in promoting gut health, and finally provide several strategies about their combined use.

Effect of Ionic and Non-Ionic Surfactants on the Pasting Characteristics and Digestive Properties of Regular and Frozen Starch for Oral Delivery

Starch is an ideal wall material for controlled release in oral delivery systems due to its non-allergic properties, availability, and cheap price. However, because of its poor mechanical behavior and high water permeability, it is necessary to modify the amphiphilic nature of starch. Surfactants are essential components to emulsify the lyophobic food ingredients. However, the interaction of starch with emulsifiers and how they affect the pasting behavior and digestion of starch are not well understood. In this paper, surfactants, such as non-ionic Tween (TW) and ionic sodium fatty acid (NaFA), with varying hydrophobic carbon chain lengths, were selected as model amphiphiles to investigate the structural, pasting, rheological properties and in vitro digestibility of regular and frozen starch samples. The results showed that, in most cases, the addition of TW reduced the viscosity of starch. However, saturated medium-chain NaFA increased the starch viscosity and rheological modulus greatly. Both surfactants inhibited starch digestion. This paper presents a comparative investigation on the effect of ionic and non-ionic surfactant on the structure and properties of corn starch, and therefore the information is useful for structural-based formulation with starch for developing colloidal delivery systems. It is also helpful for developing functional food with controllable digestion properties.

Understanding the texture and digestibility attributes of rice noodles supplemented with common vetch starch

The effects of common vetch starch (CVS) substitution on rice noodle quality were investigated, aiming to improve their texture and reduce starch digestibility. The CVS had larger granule sizes, higher amylose content and more long branch chains compared with rice starch (RS). When the CVS substitution level was 20 %, the rice noodles had the best texture quality, as the mixtures with more total starch and amylose could form denser gel structures. Moreover, the starch chains were easier to rearrange to form double helix ordered structures, resulting in a slower digestion rate. With the further increase of CVS, the noodle structure weakened and the starch digestion rate increased. This was due to the formation of looser gel structures and less ordered structures as RS granules could be easily separated into different parts by large amount of CVS with larger granule sizes, and RS with more short chains tended to be cross-linked with RS during retrogradation. With increasing CVS substitution level, the estimated glycemic index (eGI) of rice noodles decreased and then tended to be stable. Therefore, appropriate CVS substitution could improve the texture quality of rice noodles and reduce the eGI value, and the best substitution level was 20 %.

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

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

Pea-Resistant Starch with Different Multi-scale Structural Features Attenuates the Obesity-Related Physiological Changes in High-Fat Diet Mice

The present study compared the modulatory effects of different resistant starches (RSs) isolated from native (NP-RS), acid-hydrolyzed (AHP-RS), and pullulanase debranched (PDP-RS) pea starches on the corresponding in vivo metabolic responses in high fat (HF)-diet-induced obese mice. The biochemical studies on serum lipid profile and antioxidant enzyme activities were supported by histological and gene expression analyses, which suggested a potential therapeutic role for RS in regulating obesity, possibly through the production of short-chain fatty acids and the proliferation of some beneficial colonic bacteria, including Allobaculum, Bifidobacterium, Odoribacter, Clostridium, and Prevotella. Particularly, a more pronounced effect of AHP-RS with a higher proportion of the crystalline region and a more ordered double-helical alignment on improving the hyperlipidemic symptoms in obese mice induced by a HF diet was observed. Our analysis revealed that the RS3 samples seemed to be more effective than RS2 in terms of attenuating obesity in mice that were fed a HF diet.

A novel lotus seed cross-linked resistant starch: Structural, physicochemical and digestive properties

The structural properties and physicochemical characteristics of lotus seed cross-linked resistant starches (LSCSs; LS-0CS, LS-1CS, LS-2CS, LS-4CS, LS-6CS, LS-8CS, LS-10CS, and LS-12CS) with different concentrations of cross-linking agents were investigated. The degrees of cross-linking of LSCSs increased along with the amount of cross-linking agent. The higher the degree of cross-linking, the greater the degree of LSCSs granule agglomeration. The occurrence of the cross-linking reaction was confirmed by the appearance of P = O at 1,250 cm^–1 as assessed by FT-IR, and the covalent bonds formed by the phosphate group in LSCSs were mainly composed of distarch monophosphate (DMSP) as determined by ³¹P NMR. As the crosslinking degree increased, the peak strength of DMSP in starch was stronger and the specific gravity of DMSP was larger. Among the samples, LS-12CS had the highest cross-linking degree, with a greater specific gravity of DMSP. Moreover, the solubility levels of LSCSs decreased and the thermal stability and anti-digestive properties improved as the cross-linking degree increased, which was correlated with the degree of agglomeration and DMSP in LSCSs. The RS content of LS-12CS was 48.95 ± 0.86%.

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.

Formation of Intermediate Amylose Rice Starch-Lipid Complex Assisted by Ultrasonication

Due to the potential reduction in starch availability, as well as the production of the distinct physico-chemical characteristics of starch in order to improve health benefits, the formation of starch–lipid complexes has attracted significant attention for improving the quantity of resistant starch (RS) content in starchy-based foods. The purpose of this research was to apply ultrasonication to produce intermediate amylose rice (Oryza sativa L.) cv. Noui Khuea (NK) starch–fatty acid (FA) complexes. The effects of ultrasonically synthesized conditions (ultrasonic time, ultrasonic amplitude, FA chain length) on the complexing index (CI) and in vitro digestibility of the starch–FA complex were highlighted. The optimum conditions were 7.5% butyric acid with 20% amplitude for 30 min, as indicated by a high CI and RS contents. The ultrasonically treated starch–butyric complex had the highest RS content of 80.78% with a V-type XRD pattern and an additional FTIR peak at 1709 cm⁻¹. The increase in the water/oil absorption capacity and swelling index were observed in the starch–lipid complex. The pasting viscosity and pasting/melting temperatures were lower than those of native starch, despite the fact that it had a distinct morphological structure with a high proportion of flaky and grooved forms. The complexes were capable of binding bile acid, scavenging the DPPH radical, and stimulating the bifidobacterial proliferation better than native starch, which differed depending on the FA inclusion. Therefore, developing a rice starch–lipid complex can be achieved via ultrasonication.