Research advances on structural characterization of resistant starch and its structure-physiological function relationship: A review

Effect of fibers on starch structural changes during hydrothermal treatment: multiscale analyses, and evaluation of dilution effects on starch digestibility

BACKGROUND

Dietary fibers (DFs) may influence the structural, nutritional and techno-functional properties of starch within food systems. Moreover, DFs have favorable effects on the digestive system and potentially a lower glycemic index. These potential benefits may change depending on DF type. Starch processed in the presence of soluble and insoluble fibers can undergo different structural and functional changes, and the present study investigated the effects of short-chain and long-chain inulin and cellulose on the structural and digestive properties of wheat starch.

RESULTS

The combined use of differential scanning calorimetry, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) provided insights into the structural changes in starch and inulin at different levels. Short-chain and long-chain inulin had higher water retention capacity and a potential to limit starch gelatinization. The FTIR results revealed an interaction between starch and inulin. Scanning electron microscopy analysis showed morphological changes in starch and inulin after the hydrothermal treatment. Cellulose fiber was not affected by the hydrothermal treatment and had no influence on starch behavior. The structural differences observed through XRD, FTIR and scanning electron microscopy analyses between starch with and without inulin fibers did not significantly impact starch digestibility, except for the dilution effect caused by adding DFs.

CONCLUSION

The present study highlights the importance of utilizing different analytical tools to assess changes in food samples at different scales. Although short-chain and long-chain inulin could potentially limit starch gelatinization, the duration of the heat treatment (90 °C for 10 min) was sufficient to ensure complete starch gelatinization. The dilution effect caused by adding fibers was the primary reason for the effect on starch digestibility. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Multi-scale structural insights on starch digestibility of instant rice

Multi-scale structures were investigated to understand starch digestibility of instant rice. A wide range of maximum starch digested ratio, up to about 20%, was observed among instant rice prepared from different rice varieties. Instant rice with a smooth and densely packed cross-section showed slower starch digestibility than those with a porous and loosely packed structure. All samples displayed B + V type crystallinity, with V-type crystallinity negatively correlating with maximum starch digested percentage. After digestion, starch chain-length distributions were significantly altered: rapidly digested starch comprised long amylose and short amylopectin chains, while slowly digested starch comprised chains with a peak degree of polymerization (DP) around 130. These results indicate that instant rice with a compact microstructure, high V-type crystallinity, and DP 130 fractions during digestion can reduce starch digestibility. This study provides insights for food industry to develop instant rice products with slow starch digestibility, potentially improving human health.

Quantification of resistant starch content in rice after hydrothermal treatments using terahertz spectroscopy

Since hydrothermal treatments can enhance resistant starch (RS) content in rice and provide health benefits when consumed, a less laborious and non-destructive method to determine RS content is needed. Terahertz (THz) spectroscopy is hypothesized as a suitable method to quantify RS content in rice after hydrothermal treatment with its sensitivity for the intermolecular forces increase in the formation of RS. In this study, we first used the traditional in vitro hydrolysis method to determine the content of RS in rice. Then, the potential of starch absorbance peaks to quantify RS content after three commonly used hydrothermal methods, soaking, mild heat-moisture treatment, and parboiling, was investigated. The second derivative intensities of the peak at 9.0, 10.5, 12.1, and 13.1 THz were confirmed as being correlated with RS content and showed the high accuracy to predict RS content in samples (R2 > 0.96). Our results indicate the RS content of hydrothermally treated rice can be accurately quantified using these peaks.

Understanding starch gelatinization and rheology modeling of tapioca starch- NaCl/CaCl2 blends: Thermodynamic properties and gelatinization reaction kinetics during pre- and post-ultrasonication

The presence of salt can impact the fluid phase and gelatinization process of starch granules. The variation in viscosity and rheology models including the Herschel-Bulkley, the Casson model, and the power law, were determined by adding salts before and after starch ultrasonication. Non-isothermal kinetics can be utilized for the mathematical modeling of the gelatinization process and the evolution of the reaction. Unlike Na+ ions, Ca+2 ions notably elevate viscosity. The Casson model accurately predicts viscosity data. Results indicate that the addition of Na+ ions decreases yield stress by up to 60.4 %, while Ca+2 ions increase by up to 100.8 %. Adding Na+ ions decreases the required thermal energy by as much as 49.6 %, while the presence of Ca+2 ions can lead to a substantial increase of up to 337.1 % compared to control samples. The positive ∆G indicates a non-spontaneous gelatinization process. The addition of NaCl promotes a spontaneous reaction, while the addition of CaCl2 increases the Gibbs energy. The changes in entropy are minimal, implying minimal changes in starches' disorder structure.

Recrystallized resistant starch by encapsulation with konjac glucomannan: Structural changes, digestibility, and its effect on glucose response and short-term satiety in mice

The effects of the structure and digestibility of konjac glucomannan (KGM)-recrystallized resistant starch complex (KRS3) on the glycemic response and short-term satiety in mice were investigated. KRS3 samples were prepared by recrystallized debranched starch (RS3) at 50 °C, and then combined with KGM. The RS3 and KRS3 samples displayed an A-type pattern and maintained peak temperature values above 110 °C. With an increase in KGM, the swelling power and apparent viscosity of KRS3 increased. The results of in vitro and in vivo digestion revealed that KRS3 with a resistant starch content ranging from 69.4 % to 78.8 % could effectively maintain postprandial blood glucose levels. KRS3, particularly with 0.5 % KGM, slowed gastric emptying of mice from 82.7 % to 36.6 % and intestinal propulsion rate from 60.9 % to 35.3 %, resulting in strong satiety. RS3 combined with KGM could serve as a new approach to develop RS3 based foods with low glycemic responses and high-satiety.

Possible interaction between pectin and gluten alters the starch digestibility and texture of wheat bread

This study incorporated citrus pectin in wheat bread, aiming to develop breads with both desirable texture and slow starch digestibility. Results showed that starch digestibility in wheat bread decreased over the addition of pectin, and the maximum starch digested amount decreased by 6.6 % after the addition of 12 % pectin (wheat flour weight basis). The addition of pectin transferred part of the rapidly digestible starch into slowly digestible starch, and reduced the binding rate constant between slowly digestible starch and digestive enzymes, resulting in overall reduced starch digestibility. Furthermore, the addition of 4 % pectin contributed to the development of wheat bread with softer texture and increased specific volume. Mechanistically, the lowered starch digestibility of wheat bread after the pectin addition was due to (1) residual outermost swollen layer of starch granules, (2) protein and pectin interactions, and (3) increased short-range ordering of starch. This study, therefore, suggests that the addition of an appropriate amount of citrus pectin has the potential to develop bread with both a low glycemic index and desirable texture.

Structural and physicochemical properties of rice starch from a variety with high resistant starch and low amylose content

Research on the physicochemical properties of rice-derived endo-sperm high resistant starch (RS) with low amylose content (AC) is limited. In this study, we evaluated the physicochemical characteristics of such a starch variety and revealed that the starch granules exhibit a smoother, more refined surface with distinct edges, increased compactness, higher order of surface, and fewer cavities compared to those of a low RS rice variety. The starch crystal was classified as an A-type, which may be connected to the high amylose-lipid complex content. The branched internal long chains (B2 + B3) were abundant, allowing for easy entanglement with other molecular chains and a compact structure. Differential scanning calorimetry revealed the need for high temperature and energy to disrupt the double helix structure within the crystallization region of starch. Furthermore, starch viscosity analysis revealed a high cold paste viscosity, consistency, and setback value, with recrystallization yielding a stable structure, increased viscosity, and enhanced hydrolysis resistance to enzymes.

Applying Resistant Starch to Improve the Gel and Water Retention of Reduced-Fat Pork Batter

Emulsified meat products contain high animal fat content, and excessive intake of animal fat is not good for health, so people are paying more and more attention to reduced-fat meat products. This study investigated the impact of varying proportions of pork back-fat and/or resistant starch on the proximate composition, water and fat retention, texture properties, color, and rheology characteristic of pork batter. The results found that replacing pork back-fat with resistant starch and ice water significantly decreased the total lipid and energy contents of cooked pork batter (p < 0.05) while improving emulsion stability, cooking yield, texture, and rheology properties. Additionally, when the pork back-fat replacement ratio was no more than 50%, there was a significant increase in emulsion stability, cooking yield, hardiness, springiness, cohesiveness, chewiness, and L* and G' values (p < 0.05). Furthermore, resistant starch and ice water enhanced myosin head and tail thermal stability and increased G' value at 80 °C. However, the initial relaxation times significantly decreased (p < 0.05) and the peak ratio of P21 significantly increased from 84.62% to 94.03%, suggesting reduced fluidity of water. In conclusion, it is feasible to use resistant starch and ice water as a substitute for pork back-fat in order to produce reduced-fat pork batter with favorable gel and rheology properties.

Two-step modification of pullulanase and transglucosidase: A novel way to improve the gel strength and reduce the digestibility of rice starch

The multiscale structure, gel strength and digestibility of rice starch modified by the two-step modification of pullulanase (PUL) pretreatment and transglucosidase (TG) treatment for 6, 12, 18 and 24 h were investigated. The debranching hydrolysis of PUL produced some linear chains, which rearranged to form stable crystalline structures, reducing the digestible starch content, but weakening the gel strength. TG treatment connected some short chains to longer linear chains via α-1,6-glycosidic bonds, generating the structures of linear chain with fewer branches. The short branches promoted the interaction between starch molecules to form a more compact three-dimensional gel network structure, showing higher hardness and springiness. Moreover, these chains could form more stable crystals, reducing the digestible starch content, and the increase of branching degree inhibited digestive enzyme hydrolysis, reducing the digestion rate. The multiscale structure of starch tended to stabilize after TG treatment for 18 h, which could form a gel with stronger strength and lower digestibility than native starch gel. Therefore, the two-step modification of PUL and TG was an effective way to change the structure of rice starch to improve the gel strength and reduce the digestibility.

Structural characteristics, digestion properties, fermentation properties, and biological activities of butyrylated starch: A review

Butyrylated starch is produced by the esterification of hydroxyl groups in starch with butyryl groups, which improves the structural diversity of starch and expands its function and biological activity. The paper summarizes the structural properties and digestive properties, fermentation properties, and biological activities of butyrylated starch and describes the conformational relationships generated by the butyryl groups to reveal the underlying mechanisms. The butyryl groups replace the hydroxyl groups in starch and break the hydrogen bonds, which consequently changes the molecular, crystal, and granular structures of starch, while the starch structure also affects the distribution of the butyryl groups. Binding to the butyryl groups gives starch efficacy in resisting digestion, lowering the glycaemic index, releasing butyric acid in the colon, and regulating intestinal flora and metabolites. Relationships between starch structural parameters and butyric acid production and intestinal flora were also concluded to provide guidance for the rational design of butyrylated starch to improve efficacy. Moreover, based on its digestive and fermentation properties, butyrylated starch has exhibited good therapeutic efficacy for intestinal diseases, diabetes, polycystic ovary syndrome, and chronic restraint stress-induced abnormalities. This review provides a valuable reference for butyrylated starch advancement and utilization.

Subtle structural variations of resistant starch from whole cooked rice significantly impact metabolic outputs of gut microbiota

While cooked rice is widely consumed as a whole food, the specific characteristics and impact of its resistant starch (RS) on gut microbiota are largely unexplored. In this study, three rice varieties with distinct starch molecular structures were used to prepare RS from cooked rice. All three types of RS had a crystalline structure characterized as B + V type, with the V type being the predominant crystalline polymorph. Distinct differences in chain-length distributions were observed among different RSs, with rapidly fermentable starch fractions comprising short amylopectin and long amylose chains, while the degrees of polymerization (DPs) ∼ 10, 37, 65, and 105 fractions comprised the slowly fermentable starch. Jasmine rice RS showed the highest proportion of this slowly fermentable starch fraction, which appeared to be specifically utilized by Megasphaera_elsdenii_DSM_20460 OTU198. The fermentation of Jasmine RS resulted in the highest production of butyrate after 24 h, which was positively correlated with the relative abundance of Megasphaera_elsdenii_DSM_20460 OTU198. These findings collectively indicate that RS in cooked rice with a higher V type crystallinity and DPs ∼ 10, 37, 65, and 105 fractions promote butyrate production and stimulate the growth of butyrate-producing bacteria in the human gut, thereby conferring beneficial effects on gut health.

Harnessing the power of resistant starch: a narrative review of its health impact and processing challenges

Starch is a primary energy storage for plants, making it an essential component of many plant-based foods consumed today. Resistant starch (RS) refers to those starch fractions that escape digestion in the small intestine and reach the colon where they are fermented by the microflora. RS has been repeatedly reported as having benefits on health, but ensuring that its content remains in food processing may be challenging. The present work focuses on the impact RS on health and explores the different processes that may influence its presence in foods, thus potentially interfering with these effects. Clinical evidence published from 2010 to 2023 and studying the effect of RS on health parameters in adult populations, were identified, using PUBMED/Medline and Cochrane databases. The search focused as well on observational studies related to the effect of food processes on RS content. While processes such as milling, fermentation, cooking and heating seem to have a deleterious influence on RS content, other processes, such as cooling, cooking time, storage time, or water content, may positively impact its presence. Regarding the influence on health parameters, there is a body of evidence suggesting an overall significant beneficial effect of RS, especially type 1 and 2, on several health parameters such as glycemic response, insulin resistance index, bowel function or inflammatory markers. Effects are more substantiated in individuals suffering from metabolic diseases. The effects of RS may however be exerted differently depending on the type. A better understanding of the influence of food processes on RS can guide the development of dietary intake recommendations and contribute to the development of food products rich in RS.

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.

Mechanism of interaction between L-theanine and maize starch in ultrasonic field based on DFT calculations: Rheological properties, multi-scale structure and in vitro digestibility

The digestibility of starch-based foods is receiving increased attention. To date, the full understanding of how including L-theanine (THE) can modify the structural and digestive properties of starch has not been fully achieved. Here, we investigated the multi-scale structure and digestibility of maize starch (MS) regulated by THE in ultrasound field and the molecular interactions. Ultrasound disrupted the structure of starch granules and opened the molecular chains of starch, promoting increased THE binding and producing more low-order or disordered crystal structures. In this case, the aggregation of starch molecules, especially amylose, was reduced, leading to increased mobility of the systems. As a result, the apparent viscosity, G', and G" were significantly decreased, which retarded the starch regeneration. Density functional theory calculations indicated that there were mainly non-covalent interactions between THE and MS, such as hydrogen bonding and van der Waals forces. These interactions were the main factors contributing to the decrease in the short-range ordering, the helical structure, and the enthalpy change (ΔH) of MS. Interestingly, the rapidly digestible starch (RDS) content of THE modified MS (MS-THE-30) decreased by 17.89 %, while the resistant starch increased to 26.65 %. These results provide new strategies for the safe production of resistant starch.

Study of the self-assembly, drug encapsulating and delivering characteristics of short chain amylose-based type 3 resistant starch nanoparticles from Canna edulis

In developing type 3 resistant starch (RS3) from Canna edulis for use as functional food ingredients, we investigated the synthesis of C. edulis RS3 nanoparticles. Simultaneously, we explored the potential of C. edulis short-chain amylose (SCA)-based RS3 nanoparticles (RS3N) as a targeted delivery system, with a specific focus on colon targeting, yielding promising insights. Our study revealed that the degree of polymerization (DP) of C. edulis SCA, particularly the chains of DP 36- 100, exhibited a robust correlation with the particle size and physicochemical characteristics of C. edulis SCA-based RS3N. Additionally, recrystallization temperature variation (4, 25, and 45 °C) significantly influenced the self-assembly behavior of C. edulis SCA, with the preparation at 4 °C resulting in more uniform particle size distributions. In further expanding the scope of applications for C. edulis SCA-based RS3N, we harnessed the potential of Fe3O4 and curcumin (CUR) as guest molecules to assess drug encapsulation and colon-targeting capabilities. Incorporating Fe3O4 into the self-assembly system led to the production of magnetic RS3N, confirming the successful encapsulation of Fe3O4 within C. edulis SCA-based RS3N. Furthermore, in vitro experiments have demonstrated that CUR-RS3N was stable in the gastrointestinal tract and gradually released curcumin with fermentation in the colonic environment. Collectively, these findings provide invaluable insights into the intricate self-assembly behavior of C. edulis SCA with varying fine structures and recrystallization temperatures during RS3N formation. Moreover, they underscore the colon-targeted properties of C. edulis SCA-based RS3N, opening promising avenues for its application within the food industry, particularly in advanced controlled drug delivery systems.

Effects of Resistant Starch Infusion, Solely and Mixed with Xylan or Cellulose, on Gut Microbiota Composition in Ileum-Cannulated Pigs

Fermentation of dietary fiber (DF) is beneficial for gut health, but its prebiotic effects are often impeded in the distal large intestine because of the fast degradation of fermentable substrates. One way to enhance the prebiotic effect of DF is to deliver fibers to the lower parts of the gut, which can be achieved by mixing different kinds of fiber. Therefore, in the present study, an ileum-cannulated pig model was employed to investigate the fermentation influence in the large intestine by infusing resistant starch solely (RS, fast fermentable fiber) and mixing with other fibers (xylan or cellulose). Twenty-four ileum-cannulated growing pigs were divided into four groups: one control group receiving saline ileal infusions and three experimental groups infused with RS, RS with xylan, or RS with cellulose. Fecal and plasma samples were analyzed for gut microbiota composition, short-chain fatty acids (SCFAs), and blood biochemistry. Results indicated no significant differences between the RS and control group for the microbiome and SCFA concentration (p > 0.05). However, RS combined with fibers, particularly xylan, resulted in enhanced and prolonged fermentation, marked by an increase in Blautia and higher lactate and acetate production (p < 0.05). In contrast, RS with cellulose infusion enriched bacterial diversity in feces (p < 0.05). Blood biochemistry parameters showed no significant differences across groups (p > 0.05), though a trend of increased glucose levels was noted in the treatment groups (p < 0.1). Overall, RS alone had a limited impact on the distal hindgut microbiota due to rapid fermentation in the proximal gut, whereas combining RS with other fibers notably improved gut microecology by extending the fermentation process.

Including protein hydrolysates during thermal processing mitigates the starch digestion of resulted starch-based binary matrix

Staple foods with starch and protein components are usually consumed after thermal processing. To date, how including protein hydrolysates (with varied hydrolysis degrees) tailors the structure and digestion features of starch-based matrix with thermal processing has not yet been sufficiently understood. Here, corn starch (CS), soy protein isolate (SPI), and soy protein isolate hydrolysates (SPIH) with different hydrolysis time (5-60 min) were used to prepare starch-based binary matrices. With the addition of SPI or SPIH during thermal processing, the resultant binary systems exhibited higher thermal stability (breakdown visibility was increased by 1.9-10.8 times), denser networks, and fewer short-range orders (R995/1022 was decreased by up to 15.3 %). These structural changes allowed an inhibited starch digestion within the binary system, especially with increased SPI or SPIH content. Compared with CS, the content of resistant starch (RS) for CS-SPI binary complex (10:3 w/w) increased from 9.89 % to 16.69 %. Compared to SPI, SPIH inclusion displayed a stronger inhibitory effect on starch digestion since the reduced molecule size of SPIH probably enhanced its interplays with starch or amylase. For instance, the 10:3 w/w starch-SPIH 60 binary matrix possessed the highest RS content (19.07 %).

Structural, physicochemical properties and noodle-making potential of quinoa starch and type 3, type 4, and type 5 quinoa resistant starch

This study prepared type 3, type 4, and type 5 quinoa resistant starch (QRS3, QRS4, and QRS5) from quinoa starch (QS), compared their structural and physicochemical properties and evaluated their noodle-making potential. The results showed that the molecular weight of QRS3 decreased, the number of short-chain molecules increased, and its crystal type changed to B-type after gelatinization, enzymatic hydrolysis, and retrogradation. QRS4 is a phosphorylated cross-linked starch, with a surface morphology, particle size range, and crystal type similar to QS, but displaying modified thermodynamic properties. QRS5 is a complex of amylose and palmitic acid. It displays typical V-type crystals, mainly composed of long chain molecules and primarily exhibits a block morphology. The noodles prepared by replacing 20 % wheat flour with QS, QRS3 and QRS5 have higher hardness and are suitable for people who like elasticity and chewiness. QRS4 noodles are softer and suitable for people like elderly and infants who prefer soft foods. In conclusion, significant differences were evident between the fine structures, crystal types, physicochemical properties and potential applications of QS and the three QRSs. The results may expand the application of QS and QRS in the food and pharmaceutical industries.

Molecular rotor as an in-situ fluorescent probe for the degree of polymerization of α-D-1,4-glucans

Various starch synthesis and tailoring processes involve prevailing adjustments in the degree of polymerization (DP) of linear α-D-1,4-glucan chains (LGCs) for the improved functional performances. Previous studies indicated that LGCs might hinder the twisted relaxation of 9-(2-carboxy-2-cyanovinyl)-julolidine (CCVJ, a hydrophilic molecular rotor), highlighting CCVJ as a potential in-situ structural probe for LGC. In this study, glucose and its α-D-1,4 oligomers and polymers with molecular weights ranging from 0.18 kDa to 70.00 kDa were prepared as the model molecules (MM). The fluorescent emission behavior of CCVJ in various concentrations (1-5 g/L) of MM solutions or dispersions were analyzed. Results showed that for the low-DP MMs (≤ 3.98 kDa) with good aqueous stability, CCVJ emission increased by about 20 times with the DP of MMs. In contrast, CCVJ generally emitted weak DP-relevant but glucan content-dependent fluorescence in response to the interaction with high-DP MMs (> 3.98 kDa). Furthermore, a double-logarithmic linear relationship was found between the emission intensity of CCVJ and the molar-based molecular weight of glucan. The result combined with the molecular dynamic simulation suggested that CCVJ underwent surface-to-surface interaction with MMs. This study may contribute to the real-time analysis of the DP of α-D-1,4 oligoglucosides in maltodextrin and starch syrup.

A combined recrystallization and acetylation strategy for resistant starch with enhanced thermal stability and excellent short-chain fatty acid production

In this study, resistant starch (RS) with enhanced thermal stability and excellent short-chain fatty acid production was obtained using recrystallization at 50 °C of debranched waxy maize starch followed by an acetylation strategy. RS sample obtained by debranching with a 25% high concentration of native starch combined with recrystallization at 50 °C (25DBS-50 °CP) and acetylated RS (25DBS-50 °CPA) exhibited high relative crystallinity of 69.4% and 64.2%, respectively. And the peak gelatinization temperature values of them reached 116.8 °C and 111.4 °C, and the RS contents of them after cooking for 30 min remained at 35.1% and 40.0%, respectively. The acetic acid yield of 25DBS-50 °CPA was higher than that of the control group. These results indicated that recrystallization at 50 °C combined with acetylation for debranched starch could be used as a new method for regulating the digestibility and fermentation properties while developing food with a low glycemic response and specific nutritional benefits.

The impact of different concentrations of hyaluronic acid on the pasting and microstructural properties of corn starch

Starch aging in starchy foods is a major problem affecting their quality. In order to improve the viscosity and textural properties of native starch gelatinization and retrogradation, this study investigated the effect of hyaluronic acid (HA) at different concentrations (2 %, 4 %, 6 % w/w) on the pasting and microstructure of corn starch (CS). The findings revealed that the addition of HA significantly enhanced the peak viscosity, solubility, and water-holding capacity of the CS-HA mixtures. Moreover, it reduced the pasting temperature, swelling force, and leaching of amylose. All the mixtures exhibited shear thinning and thixotropic properties. The CS-HA mixtures created a thicker pseudoplastic system with significantly enhanced shear stability. The structures of the mixtures were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. It was observed that HA effectively inhibited short-term retrogradation of starch, enhanced the interaction between CS and HA, and formed a dense honeycomb three-dimensional mesh structure. In conclusion, as a novel anionic hydrocolloid, HA holds great potential to improve the retrogradation properties of starch-based products.

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

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

Characterization, health benefits, and food applications of enzymatic digestion- resistant dextrin: A review

Resistant dextrin or resistant maltodextrin (RD), a short-chain glucose polymer that is highly resistant to hydrolysis by human digestive enzymes, has shown broad developmental prospects in the food industry and has gained substantial attention owing to its lack of undesirable effects on the sensory features of food or the digestive system. However, comprehensive fundamental and application information on RD and how RD improves anti-diabetes and obesity have not yet been received. Therefore, the characterization, health benefits and application of RD in various fields are summarized and discussed in the current study. Typically, RD is prepared by the acid thermal method and possesses excellent physicochemical properties, including low viscosity, high solubility, storage stability, and low retro-gradation, which are correlated with its low molecular weight (Mw) and non-digestible glycosidic linkages. In contrast, RD prepared by the simultaneous debranching and crystallization method has low solubility and high crystallinity. The ingestion of RD can positively affect metabolic diseases (diabetes and obesity) in animals and humans by producing short-chain fatty acids (SCFAs), and facilitating the inflammatory response. Moreover, RD has been widely used in the beverage, dairy products, and dessert industries due to its nutritional value and textural properties without unacceptable quality loss. More studies are required to further explore RD application potential in the food industry and its role in the management of different chronic metabolic disorders.

Altering structure and enzymatic resistance of high-amylose maize starch by irradiative depolymerization and annealing with palmitic acid as V-type inclusion compound

This study explored a new physical modification approach to regulate enzymatic resistance of high-amylose starch for potentially better nutritional outcomes. High-amylose maize starch (HAMS) was subjected to chain depolymerization by electron beam irradiation (EBI), followed by inducing ordered structure through annealing in palmitic acid solution (APAS). APAS treatment significantly promotes the formation of ordered structure. Starch after the combinative modification showed up to 5.2 % increase in total crystallinity and up to 1.2 % increase in V-type fraction. The EBI-APAS modification led to increased gelatinization temperature (from 66.1 to 87.6 °C) and reduced final digested percentage under in vitro stimulated digestion conditions. The moderate extent of depolymerization resulted in higher enzymatic resistance, indicating that the extent of depolymerization is crucial in EBI-APAS modification. Pearson analysis showed a significant correlation between gelatinization onset temperature and digestion kinetic parameter (k1, rate constant of fast-phase digestion). Overall, the result suggests that ordered structures of degraded molecules induced by the combinative modification contribute to the enzymatic resistance of starch. This study sheds lights on future applications of EBI-APAS approach to regulate multi-scale structures and nutritional values of high-amylose starch.

Starch-ascorbyl palmitate inclusion complex, a type 5 resistant starch, reduced in vitro digestibility and improved in vivo glycemic response in mice

The prevalence of type 2 diabetes (T2D) has become a major public health concern worldwide. Slowly digested or indigestible carbohydrates such as resistant starch (RS) are associated with a low glycemic index (GI) and the decreased risk of developing T2D. Recently, starch inclusion complexes (ICs) have raised attention due to their thermally stable structure and high RS content. In this study, starch-ascorbyl palmitate (AP) ICs were produced using two different methods with hydrothermal treatments performed, and their in vitro digestion kinetics and in vivo glycemic response in C57BL/6J mice were investigated to determine their potential as a new type of RS, i.e., RS5. After treatments of annealing followed by acid hydrolysis (ANN-ACH), IC samples produced by both methods retained V-type crystalline structure. Either in their raw or treated conditions, V6h-AP ICs prepared using the "empty" V-type method exhibited a more favorable hydrolysis pattern as compared to its counterpart produced by the DMSO method in terms of a lower hydrolysis rate and equilibrium concentration (C∞) (p < 0.05). From the in vitro results, the ANN-ACH treated V6h-AP IC exhibited an estimated GI (eGI) value of 54.83, falling within the range of low GI foods and was the lowest among all tested samples (p < 0.05). Consistent with the in vitro digestion kinetics, the in vivo results showed that mice fed with ANN-ACH V6h-AP IC exhibited a modest glycemic response as evidenced by the lowest increase in postprandial blood glucose and AUC blood glucose (p < 0.05). In addition, the in vivo GI of the ANN-ACH V6h-AP IC (39.53) was the lowest among all the sample treatments and was even lower than that of the RS2 comparison (56, p < 0.05), indicating its more pronounced effect in modulating the postprandial glycemic response in mice and great potential as a new RS5.

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

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

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.

Synthesis and Functions of Resistant Starch

Resistant starch (RS) has become a popular topic of research in recent years. Most scholars believe that there are 5 types of RS. However, accumulating evidence indicates that in addition to starch-lipid complexes, which are the fifth type of RS, complexes containing starch and other substances can also be generated. The physicochemical properties and physiologic functions of these complexes are worth exploring. New physiologic functions of several original RSs are constantly being discovered. Research shows that RS can provide health improvements in many patients with chronic diseases, including diabetes and obesity, and even has potential benefits for kidney disease and colorectal cancer. Moreover, RS can alter the short-chain fatty acids and microorganisms in the gut, positively regulating the body's internal environment. Despite the increase in its market demand, RS production remains limited. Upscaling RS production is thus an urgent requirement. This paper provides detailed insights into the classification, synthesis, and efficacy of RS, serving as a starting point for the future development and applications of RS based on the current status quo.

Influence pathways of nanocrystalline cellulose on the digestibility of corn starch: Gelatinization, structural properties, and α-amylase activity perspective

This work focused on the pathways by which NCC regulated the digestibility of corn starch. The addition of NCC changed the viscosity of the starch during pasting, improved the rheological properties and short-range order of the starch gel, and finally formed a compact, ordered, and stable gel structure. In this respect, NCC affected the digestion process by changing the properties of the substrate, which reduced the degree and rate of starch digestion. Moreover, NCC induced changes in the intrinsic fluorescence, secondary conformation, and hydrophobicity of α-amylase, which lowered its activity. Molecular simulation analyses suggested that NCC bonded with amino acid residues (Trp 58, Trp 59, and Tyr 62) at the active site entrance via hydrogen bonding and van der Waals forces. In conclusion, NCC decreased CS digestibility by modifying the gelatinization and structural properties of starch and inhibiting α-amylase activity. This study provides new insights into the mechanisms by which NCC regulates starch digestibility, which could be beneficial for the development of functional foods to tackle type 2 diabetes.

Core-shell starch as a platform for reducing starch digestion and saturated fat intake

Ill-balanced diets, especially high-carbohydrate and high-fat diets, have led to an explosion of diabetes and cardiovascular diseases worldwide, posing great threats to human health. The structural design of functional foods can offer promising solutions to these afflictions. Here, we introduce a versatile core-shell starch made from food-grade starch and alcohol-soluble protein to reduce starch digestion and saturated fat intake. The fabrication of core-shell structure is realized through an anti-solvent method, assisted by electrostatic interaction, which is generalizable to starches and proteins from different sources and feasible for scale-up production. The protein shell imparts a higher gelatinization temperature and a lower pasting viscosity to the starch, suggesting restricted granule swelling, which leads to a reduced starch digestibility as proved by in vitro digestion studies. The hypoglycemic effect of core-shell starch is demonstrated in vivo. We also show that the application of core-shell starch can be extended to oil encapsulants and saturated fat replacers due to the impact of protein shell on the surface hydrophobicity of the starch. These results may advance the establishment of healthy diets and the tackling of diet-related diseases.

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.

Inhibitory effects of chlorophylls and its derivative on starch digestion in vitro

Chlorophylls (Chls) have been shown to help regulate blood glucose levels. In this study, the effects of Chls and its derivative, pheophytin a (Phe a), on starch digestion in vitro were investigated. Chls significantly decreased starch hydrolysis while increasing resistant starch content (p < 0.05). SEM revealed that Chls either existed in free form or was absorbed and embedded on the surface of starch granules. Spectroscopic analysis and molecular docking demonstrated that Chls had a dual effect: (1) the phytol chain of Chls formed a double helix structure with starch, which may hinder the starch-enzyme contacts; and (2) the porphyrin ring of Chls interacted with amino acid residues of α-amylase and α-glucosidase to change the characteristics of enzymes, thereby inhibiting their activities. The investigation may serve as motivation for developing healthful starchy foods rich in Chls and enhancing the selection of foods for diabetics and hyperglycemias.

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.

Study of unripe and inferior banana flours pre-gelatinized by four different physical methods

This study aimed to prepare the pre-gelatinized banana flours and compare the effects of four physical treatment methods (autoclaving, microwave, ultrasound, and heat-moisture) on the digestive and structural characteristics of unripe and inferior banana flours. After the four physical treatments, the resistant starch (RS) content values of unripe and inferior banana flours were decreased from 96.85% (RS2) to 28.99-48.37% (RS2 + RS3), while C∞ and k values were increased from 5.90% and 0.039 min^-1 to 56.22-74.58% and 0.040-0.059 min^-1, respectively. The gelatinization enthalpy (ΔHg) and I_1047/1022 ratio (short-range ordered crystalline structures) were decreased from 15.19 J/g and 1.0139 to 12.01-13.72 J/g, 0.9275-0.9811, respectively. The relative crystallinity decreased from 36.25% to 21.69-26.30%, and the XRD patterns of ultrasound (UT) and heat-moisture (HMT) treatment flours maintained the C-type, but those samples pre-gelatinized by autoclave (AT) and microwave (MT) treatment were changed to C + V-type, and heat-moisture (HMT) treatment was changed to A-type. The surface of pre-gelatinized samples was rough, and MT and HMT showed large amorphous holes. The above changes in structure further confirmed the results of digestibility. According to the experimental results, UT was more suitable for processing unripe and inferior banana flours as UT had a higher RS content and thermal gelatinization temperatures, a lower degree and rate of hydrolysis, and a more crystalline structure. The study can provide a theoretical basis for developing and utilizing unripe and inferior banana flours.

Multi-Scale Structural Insights into Enzymatically Hydrolyzed Lentil Starch Concentrates Prepared by In Vitro Method Using Different Types of Enzymes

This study was undertaken to investigate the enzymatic hydrolysis of lentil starch concentrates from conventional cooked seeds (CCLSC) by the action of different types of enzymes, including pancreatin (PC-EHSC), heat-stable α-amylase (HS-EHSC), β-amylase (βA-EHSC), amyloglucosidase (AMG-EHSC), and multi-enzymes (βA-HS-AMG-EHSC); their multi-scale structural characteristics of the enzymatic hydrolysis products of lentil starch concentrates were compared. The morphological features distinguished among different samples. The Fourier-transform infrared spectroscopy and solid-state ¹³C CP/MAS NMR spectral features indicated the possible formation of a binary and ternary complex among amylose, protein and lipids. The X-ray diffraction results revealed that the V-type characteristic diffraction peaks were more obvious for samples including PC-EHSC and βA-EHSC, which was in line with their lowest polydispersity index (DP_n). PC-EHSC and βA-EHSC also showed an increased peak intensity of the scattering maximum on the small-angle X-ray scattering spectra, whereas CCLSC exhibited an overall lower peak intensity within the studied q range of scattering. The highest XRD crystallinity and the lowest DP_n value obtained for PC-EHSC indicated that the starch polymers modified by pancreatin could produce glucan chains with a comparatively homogenous M_w distribution that are readily recrystallized by hydrogen bonding through chain aggregation. Comparatively, the lowest relative crystallinity for HS-EHSC obtained from XRD suggested that thermostable α-amylolysis was unfavorable for the formation of starch structure with a higher degree of molecular order. This study could provide useful information for the needed research to obtain a deeper understanding of the impact of different amylolysis actions on the structural organization of starch hydrolysates and to provide a theoretical foundation for the development of fermentable enzymatically hydrolyzed starch with well-tailored physiological properties.

Meta-analysis reveals gut microbiome and functional pathway alterations in response to resistant starch

Resistant starch (RS) has the ability to improve the structure of the gut microbiota, regulate glucolipid metabolism and maintain the health of the human body, and has been extensively studied by many scholars in recent years. However, previous studies have provided a wide range of results on the differences in the gut microbiota after RS intake. In this article, we performed a meta-analysis of a total of 955 samples of 248 individuals from the seven studies included to compare the gut microbiota of the baseline and the end-point of RS intake. At the end-point, RS intake was related to a lower gut microbial α-diversity and higher relative abundance of Ruminococcus, Agathobacter, Faecalibacterium and Bifidobacterium, and the functional pathways of the gut microbiota related to the carbohydrate metabolism, lipid metabolism, amino acid metabolism and genetic information processing were higher. Different types of resistant starch and different populations led to varied responses on the gut microbiome. The altered gut microbiome may contribute to improve the blood glucose level and insulin resistance, which may be a potential treatment route for diabetes, obesity and other metabolic diseases.

Extraction, identification, and starch-digestion inhibition of phenolics from Euryale ferox seed coat

BACKGROUND

Euryale ferox is an important cash crop and valuable tonic in traditional medicine. The seeds of E. ferox are rich in starch, which is hard to digest, and the digestion speed is significantly slower than that of rice starch. The goal of this study was to evaluate the effects of E. ferox seed-coat phenolics (EFCPs) on the digestion of E. ferox seed starch.

RESULTS

EFCPs were extracted and identified by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. We optimized the extraction parameters, and the final extraction yield was about 1.49%. We identified seven phenolics from the E. ferox seed-coat extracts: gallic acid, digalloylhexoside, catechin, procyanidin B2, epicatechin, ellagic acid, and epicatechin gallate. Quantitative analysis results showed that the E. ferox seed phenolics mainly distributed in the seed coat and the gallic acid, digalloylhexoside, and epicatechin gallate were three main phenolic compounds. The phenolics displayed strong inhibitory activities on α-glucosidase and α-amylase with an IC₅₀ of 3.25 μg mL^-1 and 1.36 mg mL^-1 respectively. Furthermore, these phenolics could interact with starch by hydrogen bonds, which might make its starch more difficult to digest.

CONCLUSION

Our investigation suggests that the EFCPs can strongly inhibit the digestion of E. ferox seed starch by inhibiting the α-amylase and α-glucosidase activities and interacting with starch by hydrogen bonds; therefore, E. ferox seeds have a promising application prospect in foods for hypoglycemia. © 2023 Society of Chemical Industry.

Effect of Calcium Hydroxide on Physicochemical and In Vitro Digestibility Properties of Tartary Buckwheat Starch-Rutin Complex Prepared by Pre-Gelatinization and Co-Gelatinization Methods

This study examined the effect of calcium hydroxide (Ca(OH)₂, 0.6%, w/w) on structural, physicochemical and in vitro digestibility properties of the complexed system of Tartary buckwheat starch (TBS) and rutin (10%, w/w). The pre-gelatinization and co-gelatinization methods were also compared. SEM results showed that the presence of Ca(OH)₂ promoted the connection and further strengthened the pore wall of the three-dimensional network structure of the gelatinized and retrograded TBS-rutin complex, indicating the complex possessed a more stable structure with the presence of Ca(OH)₂, which were also confirmed by the results of textural analysis and TGA. Additionally, Ca(OH)₂ reduced relative crystallinity (RC), degree of order (DO) and enthalpy, inhibiting their increase during storage, thereby retarding the regeneration of the TBS-rutin complex. A higher storage modulus (G') value was observed in the complexes when Ca(OH)₂ was added. Results of in vitro digestion revealed that Ca(OH)₂ retarded the hydrolysis of the complex, resulting in an increase in values in slow-digestible starch and resistant starch (RS). Compared with pre-gelatinization, the complex process prepared with the co-gelatinization method presented lower RC, DO, enthalpy, and higher RS. The present work indicates the potential beneficial effect of Ca(OH)₂ during the preparation of starch-polyphenol complex and would be helpful to reveal the mechanism of Ca(OH)₂ on improving the quality of rutin riched Tartary buckwheat products.

High-amylose maize starch: Structure, properties, modifications and industrial applications

High-amylose maize refers to a special type of maize cultivar with a 50 %-90 % amylose content of the total starch. High-amylose maize starch (HAMS) is of interest because it possesses unique functionalities and provides many health benefits for humans. Therefore, many high-amylose maize varieties have been developed via mutation or transgenic breeding approaches. From the literature reviewed, the fine structure of HAMS is different from the waxy and normal corn starches, influencing its gelatinization, retrogradation, solubility, swelling power, freeze-thaw stability, transparency, pasting and rheological properties, and even in vitro digestion. HAMS has undergone physical, chemical, and enzymatical modifications to enhance its characteristics and thereby broaden its possible uses. HAMS has also been used for the benefit of increasing resistant starch levels in food products. This review summarizes the recent developments in our understanding of the extraction and chemical composition, structure, physicochemical properties, digestibility, modifications, and industrial applications of HAMS.

Influence of Resistant Starch in Whole Rice on Human Gut Microbiota─From Correlation Implications to Possible Causal Mechanisms

Rice is the main staple food for a large population around the world, while it generally has a high glycemic index and low resistant starch (RS) content. Although many strategies have been applied to develop healthier rice products with increased RS contents, their actual effects on gut microbiota and human health remain elusive. In this review, currently available production methods of rice RS are briefly summarized, followed by a critical discussion on their interactions with gut microbiota and subsequent effects on human health, from correlation implications to causal mechanisms. Different contents, types, and structures of RS have been produced by strategies such as genetic manipulation and controlling cooking conditions. The difference can largely determine effects of rice RS on gut microbiota composition and metabolites by specific RS-gut microbiota interactions. This review can thus help the rice industry develop rice products with desirable RS contents and structures to generally improve human health.

Arenga pinnata Resistant Starch Modulate Gut Microbiota and Ameliorate Intestinal Inflammation in Aged Mice

This study aimed to compare the regulatory effects of Arenga pinnata retrograded starch (APRS), Arenga pinnata starch (APS), and whole Arenga pinnata flour (APF) on gut microbiota and improvement of intestinal inflammation in aged mice. APF, APS, and APRS altered gut microbiota composition and exhibited different prebiotic effects. Bifidobacterium showed the greatest increase in feces of aged mice fed APF. The abundance of genus Lachnospiraceae_NK4A136 was highest in the APS group. APRS supplementation led to a greatest increasement in abundance of Lactobacillus, Roseburia, and Faecalibacterium prausnitzii. APRS induced significantly more short-chain fatty acid (SCFAs) production than APF and APS. APF, APS, and APRS treatments improved intestinal inflammation in aged mice and the order of ameliorative effect was APRS > APS > APF. APRS significantly decreased relative mRNA expression of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) and increased anti-inflammatory cytokines (IL-10). In addition, APF, APS, and APRS significantly downregulated the relative mRNA expression of senescence-associated gene p53 and upregulated the expression of anti-aging gene Sirt1. These results provide potentially useful information about the beneficial effects of Arenga pinnata products on human health.