Starch-phenolic complexes are built on physical CH-π interactions and can persist after hydrothermal treatments altering hydrodynamic radius and digestibility of model starch-based foods

Insight into the binding mode of different lotus seed natural starch-phenolic acids complexes

This study investigated the influence of natural lotus seed starch on the adsorption of seven endogenous phenolic acids present in lotus seeds. The research delineated the interaction mechanisms and subsequently analyzed the alterations in starch characteristics following adsorption. A comprehensive suite of analytical techniques, including adsorption isotherms, 13C NMR, DSC, LF-NMR, rheology, particle size, and potential analyses was employed. All seven phenolic acids were found to spontaneously and physically bind to natural lotus seed starch, primarily through hydrogen bonding, van der Waals interactions, and hydrophobic forces. Post adsorption, the starch granules exhibited diminished crystallinity and reduced bound-water content. Notably, p-coumaic acid, chlorogenic acid, and p-hydroxybenzoic acid formed single helical complexes with the starch, whereas coumalic acid formed non-encapsulated compounds. The adsorption process resulted in increased total color difference (ΔE), particle size, zeta potential, and gelatinization enthalpy of the starch granules, while concurrently decreasing granule-bound water content, glass transition temperature (Tg), and the loss modulus (G″) of the starch pastes. Consequently, the formation of starch-phenolic acid complexes reduces the bound water content, which in turn diminishes the storage modulus and regeneration capability of the starch paste. These findings provide a novel basis for understanding the mechanisms governing the interactions between starch and phenolic acids, thereby elucidating the alterations in the properties of phenolic acid- and starch-rich foods during processing.

Effect of isoflavone structures on the formation of starch-isoflavone complexes: Experimental and molecular dynamics analysis

Isoflavones were the commonly polyphenols capable of forming inclusion complexes with starch to slow starch enzymatic digestion. However, the impact of isoflavone structures on the formation of starch-isoflavone complexes was not well understood. In this study, isoflavones with distinct structurally differences, including daidzein, genistein, biochanin A, genistin, and puerarin, were selected to examine the interaction between starch and these isoflavones utilizing both experimental and molecular dynamics analysis. The experimental findings showed that daidzein and genistein produced more V-type crystallites with starch, resulting in a greater decrease in starch digestibility compared to other isoflavones. Molecular dynamics simulations suggested that daidzein and genistein, which had smaller molecular size and less hydroxyl groups, formed fewer hydrogen bonds but more inclusion complexes with starch. It appeared that the number of hydroxyl groups and molecular size of isoflavones played a crucial role in the interaction between starch and isoflavones, ultimately influencing the formation of V-type starch crystallites.

Wheat starch-Lonicera caerulea berry polyphenols complex regulates blood glucose and improves intestinal flora in type 2 diabetic mice

Resistant starch (RS) reduces or delays the digestion of carbohydrates and glucose synthesis, thereby lowering postprandial blood glucose levels. The wheat starch-Lonicera caerulea berry polyphenols (WS-LCBP) complex was constructed using high hydrostatic pressure (HHP). The effects of intragastric administration of WS or WS-LCBP on blood glucose in T2DM model mice. RS in the composite preparation formed by HHP and 10 % LCBP at 600 MPa for 30 min increased from 7.65 % to 49.66 %. WS-LCBP formed an A + V-type crystal structure of the polyhydroxyl non-inclusion complex, which hindered the digestion of WS into glucose. Compared with LCBP intake, which caused 8.3 % reduction in 2-h postprandial blood glucose (p < 0.05), Homeostatic model assessment for insulin resistance demonstrated a 35.3 % decrease (p < 0.001) with WS-LCBP administration. Western blotting demonstrated that exposure to WS-LCBP activated the GLP-1R/PI3K/AKT signaling pathway in the liver tissue of T2DM mice, reducing insulin resistance. Furthermore, the concentration of short-chain fatty acids was markedly elevated. The structure and abundance of the intestinal flora were enhanced. The WS-LCBP complex demonstrated a more pronounced improvement than LCBP supplementation alone. This study offers a novel perspective and theoretical foundation for the regulation of postprandial blood glucose levels by polyphenol starch-based food biomacromolecules and their potential applications in starchy foods.

Current advances in the interaction mechanisms, nutritional role and functional properties of phenolic compound-starch complexes

This review explores starch-phenolic compound complexes' formation mechanisms, structural characteristics, and functional roles. These complexes alter starch properties, enhance its resistance to digestion, and modulate enzyme activity, with significant implications for glycemic control. A critical discussion of preparation methods and characterization techniques is presented, emphasizing their application in functional food design and health-oriented products. The review highlights the potential of these complexes to address metabolic disorders, offering valuable insights for advancing food science and nutrition.

Integrative approach to modifying banana starch: The role of physical treatment and polyphenol enrichment on physicochemical and digestive characteristics

This study assessed the effects of three physical methods-dielectric barrier discharge (DBD) plasma, ultrasound, and heat-moisture treatment-coupled with resveratrol enrichment, on the physicochemical and digestive properties of banana starch. The findings indicated that each physical treatment enhanced the complex index between starch and resveratrol. Scanning electron microscopy and X-ray diffraction analyses revealed that the inherent A-type crystallinity of the starch remained unchanged after modifications. Heat-moisture treatment induced the most profound alterations in the long-range and short-range order. While DBD plasma and ultrasound did not affect the granular morphology, heat-moisture treatment caused the most significant disruption. Furthermore, DBD plasma and ultrasound treatments significantly enhanced the solubility, gelatinization temperature, and viscoelastic properties of banana starch, while having a negligible effect on its digestibility. After heat-moisture treatment, banana starch exhibited significantly higher gelatinization temperatures (To = 72.13 °C, Tp = 82.56 °C, Tc = 83.69 °C) and a digestion rate of 82.37 %, compared to those observed with DBD plasma and ultrasound treatments, despite reduced solubility and viscoelasticity. Additionally, all three treatments improved the oil absorption capacity of the starch. The integration of resveratrol not only consolidated starch structure but also augmented its thermal stability and resistant starch content. These findings provide empirical support for modifying banana starch and expanding its application in food industry.

Modulation of Gut Microbiota by the Complex of Caffeic Acid and Corn Starch

To understand the impact of different types of polyphenol-starch complexes on digestibility and gut microbiota, caffeic acid (CA) and corn starch (CS) complexes were prepared by coheating and high-pressure homogenization. The resistant starch content in CS coheated with CA (HCS-CA) and HCS-CA after high-pressure homogenization (HCS-CA-HPH) was 47.75 and 56.65%, respectively. Fourier transform infrared spectroscopy and X-ray diffraction analysis revealed hydrogen bonding in coheated samples and enhanced V-complex formation with high-pressure homogenization. The in vitro-digested complexes were of the B + V type, with higher relative crystallinity and short-range ordering of HCS-CA-HPH. Fermentation of the digested complex with human feces increased the yield of acetate, butyrate, and total short-chain fatty acids (SCFAs), which was more pronounced for HCS-CA-HPH. HCS-CA increased torques-Ruminococcaceae abundance, while HCS-CA-HPH boosted Prevotella, Roseburia, Lachnospiraceae, and Lachnospiraceae-NK4A136. Overall, CA and CS complexes enhanced beneficial bacteria and increased SCFA production.

Research progress on the regulation of starch-polyphenol interactions in food processing

Starch is a fundamental material in the food industry. However, the inherent structural constraints of starch impose limitations on its physicochemical properties, including thermal instability, viscosity, and retrogradation. To address these obstacles, polyphenols are extensively employed for starch modification owing to their distinctive structural characteristics and potent antioxidant capabilities. Interaction between the hydroxyl groups of polyphenols and starch results in the formation of inclusion or non-inclusion complexes, thereby inducing alterations in the multiscale structure of starch. These modifications lead to changes in the physicochemical properties of starch, while simultaneously enhancing its nutritional value. Recent studies have demonstrated that both thermal and non-thermal processing exert a significant influence on the formation of starch-polyphenol complexes. This review meticulously analyzes the techniques facilitating complex formation, elucidating the critical factors that dictate this process. Of noteworthy importance is the observation that thermal processing significantly boosts these interactions, whereas non-thermal processing enables more precise modifications. Thus, a profound comprehension and precise regulation of the production of starch-polyphenol complexes are imperative for optimizing their application in various starch-based food products. This in-depth study is dedicated to providing a valuable pathway for enhancing the quality of starchy foods through the strategic integration of suitable processing technologies.

Effect of adding various supplements on physicochemical properties and starch digestibility of cooked rice

This study investigated the physicochemical modifications of cooked rice caused by adding various supplements (rapeseed oil, dried wasabi powder, and dried chili pepper powder). The physicochemical and digestive properties of treated cooked rice were analyzed using multiple techniques to determine the impact of supplements on the rice quality, including its starch digestibility. All samples with added supplements showed an increase in surface firmness (0.77-0.95 kg·m/s2 (N)) and a decrease in thickness (2.23-2.35 mm) and surface adhesiveness (1.43-7.22 J/m3). Compared to the control group, two absorption peaks at 2856 and 1748 cm-1 and new signals at 1683 and 1435 cm-1 appeared in the Fourier transform infrared (FTIR) spectroscopy. Analysis of FTIR results revealed that the interaction force was mainly through noncovalent interactions. Moreover, adding supplements increased the resistant starch (RS) levels in all samples. Scanning electron microscopy (SEM) suggested that oil-enriched phases, proteins, and polyphenols could cause large agglomeration and loose gel structure. These results suggested the formation of amylose-guest molecule complexes, which may influence starch functionality. Our work could provide insight into the starch-supplement interactions and the key factors affecting starch digestibility.

The influence mechanism of pH and polyphenol structures on the formation, structure, and digestibility of pea starch-polyphenol complexes via high-pressure homogenization

The formation of starch-polyphenol complexes through high-pressure homogenization (HPH) is a promising method to reduce starch digestibility and control postprandial glycemic responses. This study investigated the combined effect of pH (5, 7, 9) and polyphenol structures (gallic acid, ferulic acid, quercetin, and tannic acid) on the formation, muti-scale structure, physicochemical properties, and digestibility of pea starch (PS)-polyphenol complexes prepared by HPH. Results revealed that reducing pH from 9 to 5 significantly strengthened the non-covalent binding between polyphenols and PS, achieving a maximum complex index of 13.89 %. This led to the formation of complexes with higher crystallinity and denser structures, promoting a robust network post-gelatinization with superior viscoelastic and thermal properties. These complexes showed increased resistance to enzymatic digestion, with the content of resistant starch increasing from 28.66 % to 42.00 %, rapidly digestible starch decreasing from 42.82 % to 21.88 %, and slowly digestible starch reducing from 71.34 % to 58.00 %. Gallic acid formed the strongest hydrogen bonds with PS, especially at pH 5, leading to the highest enzymatic resistance in PS-gallic acid complexes, with the content of resistant starch of 42.00 %, rapidly digestible starch of 23.35 % and slowly digestible starch of 58.00 %, and starch digestion rates at two digestive stages of 1.82 × 10-2 min-1 and 0.34 × 10-2 min-1. These insights advance our understanding of starch-polyphenol interactions and support the development of functional food products to improve metabolic health by mitigating rapid glucose release.

Oral soluble shell prepared from OSA starch incorporated with tea polyphenols for the microencapsulation of Sichuan pepper oleoresin: Characterization, flavor stability, release mechanisms and its application in mooncake

The market share of Sichuan pepper oleoresin (SPO) in the flavor industry is increasing steadily; however, its high volatility, low water solubility, and poor stability continue to pose significant challenges to application. The microencapsulation prepared by emulsion embedding and spray drying is considered as an effective technique to solve the above problems. Sodium octenyl succinate starch (OSA starch) and tea polyphenols (TPs) were used to develop OSA-TPs complex as encapsulants for SPO to prepare orally soluble microcapsules. And the optimum doping of TPs was determined. SPO microcapsules have good properties with high encapsulation efficiency up to 88.13 ± 1.48% and high payload up to 41.58 ± 1.86% with low water content and high heat resistance. The binding mechanism of OSA starch with TPs and its regulation mechanism and effect on SPOs were further analyzed and clarified. The binding mechanism between OSA starch and TPs was clarified in further analyses. The OSA-TPs complexes enhanced the rehydration, release in food matrix and storage stability of SPO, and exhibited good sensory immediacy. Flavor-improved mooncakes were successfully developed, achieving the combination of mooncake flavor and SPO flavor. This study provided a valuable way to prepare flavoring microcapsules suitable for the catering industry, opened up the combined application of SPO and bakery ingredients, and was of great practical value and significance for improving the processing quality of flavor foods, driving the development of the SPO industry, and enhancing the national dietary experience.

Strategic exploration of whole grain cereals in modulating the glycaemic response

In the current context, diabetes presents itself as a widespread and complex global health issue. This study explores the significant influence of food microstructure and food matrix components interaction (protein, lipid, polyphenols, etc.) on the starch digestibility and the glycaemic response of post-prandial glycemia, focusing on the potential effectiveness of incorporating bioactive components from whole grain cereals into dietary strategies for the management and potential prevention of diabetes. This study aims to integrate the regulation of postprandial glycaemic homeostasis, including the complexities of starch digestion, the significant potential of bioactive whole grain components and the impact of food processing, to develop a comprehensive framework that combines these elements into a strategic approach to diabetes nutrition. The convergence of these nutritional strategies is analyzed in the context of various prevalent dietary patterns, with the objective of creating an accessible approach to mitigate and prevent diabetes. The objective remains to coalesce these nutritional paradigms into a coherent strategy that not only addresses the current public health crisis but also threads a preventative approach to mitigate future prevalence and impact.

Macromolecular, thermal, and nonthermal technologies for reduction of glycemic index in food-A review

Consumers rely on product labels to make healthy choices, especially with regard to the glycemic index (GI) and glycemic load (GL), which identify foods that stabilize blood sugar. Employing both thermal and nonthermal processing techniques can potentially reduce the GI, contributing to improved blood sugar regulation and overall metabolic health. This study concentrates on the most current advances in GI-reduction food processing technologies. Food structure combines fiber, healthy fats, and proteins to slow digestion, reducing GI. The influence of thermal approaches on the physical and chemical modification of starch led to decreased GI. The duration of heating and the availability of moisture also determine the degree of hydrolysis of starch and the glycemic effects on food. At a lower temperature, the parboiling revealed less gelatinization and increased moisture. The internal temperature of the product is raised during thermal and nonthermal treatment, speeds up retrogradation, and reduces the rate of starch breakdown.

Structural characteristics and in vitro starch digestibility of oil-modified cooked rice with varied addition manipulations

Lipid has crucial applications in improving the quality of starchy products during heat processing. Herein, the influence of lipid modification and thermal treatment on the physicochemical properties and starch digestibility of cooked rice prepared with varied addition manipulations was investigated. Rice bran oil (RO) and medium chain triglyceride oil (MO) manipulations were performed either before (BC) or after cooking (AC). GC-MS was applied to determine the fatty acid profiles. Nutritional quality was analyzed by quantifying total phenolics, atherogenic, and thrombogenic indices. All complexes exhibited higher surface firmness, a soft core, and less adhesive. FTIR spectrum demonstrated that the guest component affected some of the dense structural attributes of V-amylose. The kinetic constant was in the range between 0.47 and 0.86 min-1 wherein before mode presented a higher value. The lowest glucose release was observed in the RO_BC sample, whereas the highest complexing index was observed in the RO_AC sample, indicating that the dense molecular configuration of complexes that could resist enzymatic digestion was more critical than the quantity of complex formation. Despite the damage caused by mass and heat transfer, physical barrier, intact granule forms, and strengthened dense structure were the central contributors affecting the digestion characteristics of lipid-starch complexes.

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

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

Effect of polyphenols from Ascophyllum nodosum seaweeds on the rheology and digestion of corn starch gels and gluten-free bread features

The main objective of this work is to study the effect of polyphenols, from the brown seaweed Ascophyllum nodosum, on the structure and digestion behaviour of gels at two corn starch concentrations (1.95 and 5.00% w/w) as well as the structure, color and texture features of crumbs from gluten-free breads. Adsorption isotherms of polyphenols on native and gelled starches were carried out and modelled by means of Langmuir and Henry models, respectively. The formation and characteristics of tested gels were rheologically monitored by means of heating ramp, time sweep at high temperature, cooling ramp and frequency sweep at 25 °C. Elastic modulus values decreased with the presence of polyphenols. Additionally, the polyphenols significantly decreased the digestion rate, measured by both chemical and rheological procedures, and the final concentration of digested starch. Finally, the presence of polyphenols in breads increased the hardness and chewiness values and decreased the cohesiveness and resilience values as well as the crumb hardening during storage.

Inhibition of α-amylase digestion by a Lonicera caerulea berry polyphenol starch complex revealed via multi-spectroscopic and molecular dynamics analyses

Polyphenol-starch complexes exhibit synergistic and beneficial effects on both polyphenols and resistant starches. This study evaluates the inhibitory effects and mechanisms of α-amylase on a Lonicera caerulea berry polyphenol-wheat starch (LPWS) complex following high hydrostatic pressure treatments of 400 MPa for 30 min and 600 MPa for 30 min. The IC50 values for α-amylase inhibition by the complex were 3.61 ± 0.10 mg/mL and 3.42 ± 0.08 mg/mL at a 10 % (w/w) polyphenol content. This interaction was further supported by Fourier-transform infrared spectroscopy and circular dichroism, which confirmed that the alpha helix component of the secondary structure of α-amylase was reduced due to the complex. Multifluorescence spectroscopy revealed that the complex induces changes in the microenvironment of fluorophores surrounding the α-amylase active site. Molecular dynamics simulations and molecular docking revealed that the active site of amylose within the complex becomes enveloped in polyphenol clusters. This wrapping effect reduced the hydrogen bonds between amylose and α-amylase, decreasing from 16 groups to just one group. In summary, the LPWS complex represents a low-digestible carbohydrate food source, thus laying the groundwork for the research and development of functional foods aimed at postprandial hypoglycemic effects.

Starch films loaded with tannin: the study of rheological and physical properties

Recently, the research on innovative food packaging has been oriented toward biodegradable materials to lower the environmental impact generated by conventional plastics. The films often carry functional additives interacting with the matrix and modifying its physical properties. In this work tannin, a scarcely exploited active additive, was used to obtain potato starch-based films, and its content was optimized on the basis of mechanical and microscopic tests. Rheological measurements were adopted to evaluate the tannin-starch interaction and the microstructure of the film forming solutions (FFSs). Their thickness, color, thermal conductivity, elastic modulus (Eel), elongation at break (EAB), surface wettability and water solubility were evaluated. Furthermore, microstructure was investigated through Fourier-transform infrared spectroscopy (FTIR), polarized light (POM) and scanning electron microscopy (SEM). It was observed that all FFSs behave as weak gels and tannin addition weakens the gel structure and decreases the gelatinization temperature from about 60 °C to 57 °C. Plastic and deformable films (Eel = 1.96 MPa and EAB = 189 %) were obtained at low tannin fractions, whereas, at a higher concentration, stiffer films (Eel = 12 MPa and EAB = 10 %), with hydrophobic behavior were produced. Among the tested tannin fractions, an intermediate value of 1.7 % (w/w) was found to be promising for industrial purposes.

Regulating the physicochemical, structural characteristics and digestibility of potato starch by complexing with different phenolic acids

The effects of ferulic acid (FA), protocatechuic acid (PA), and gallic acid (GA) on the physicochemical characteristics, structural properties, and in vitro digestion of gelatinized potato starch (PS) were investigated. Rapid viscosity analysis revealed that the gelatinized viscosity parameters of PS decreased after complexing with different phenolic acids. Dynamic rheology results showed that phenolic acids could reduce the values of G' and G″ of PS-phenolic acid complexes, demonstrating that the addition of phenolic acids weakened the viscoelasticity of starch gel. Fourier-transform infrared spectra and X-ray diffraction results elucidated that phenolic acids primarily reduced the degree of short-range ordered structure of starch through non-covalent interactions. The decrease in thermal stability and the more porous microstructure of the complexes confirmed that phenolic acids could interfere with the gel structure of the starch. The addition of different phenolic acids decreased the rapidly digestible starch (RDS) content and increased the resistant starch (RS) content, with GA exhibiting the best inhibitory capacity on starch in vitro digestibility, which might be associated with the number of hydroxy groups in phenolic acids. These results revealed that phenolic acids could affect the physicochemical characteristics of PS and regulate its digestion and might be a potential choice for producing slow digestibility starch foods.

Lowering glycemic levels via gastrointestinal tract factors: the roles of dietary fiber, polyphenols, and their combination

Dietary fiber (DF) and polyphenols (DP) are typical blood sugar-lowering components, and both play distinct yet interconnected roles in exerting their blood sugar-lowering effects. We comprehensively summarized the single and combined effects of DF and DP on blood glucose homeostasis through regulating the relevant factors in the upper gastrointestinal tract (UGT) and lower gastrointestinal tract (LGT). In the UGT, DF slowed down glucose metabolism by enhancing digesta viscosity and hindering enzyme-substrate interaction. DP primarily targeted enzymes and substrates. When combined, DP enhanced the adsorption capacity of DF for glucose. DF weakened DP's inhibitory effect on enzymes. Both DF and DP disrupted glucose intestinal uptake via physical or genomic modulation, but the co-consumption of DF and DP demonstrated a lower inhibitory effect on glucose uptake than DP alone. In the LGT, DF and DP showed synergistic or antagonistic effects on gut microbiota. Remarkably, whole foods exhibited potent prebiotic effects due to their compound-rich matrix, potentially enhancing glucose homeostasis and expanding dietary options for glucose regulation research.

Probing gallic acid-starch interactions through Rapid ViscoAnalyzer in vitro digestion

Phenolic compounds are known inhibitors of starch digestion through binding with α-amylase. However, a growing body of research shows that phenolic-starch interactions at the molecular level may interfere with this inhibition potential. In this study, we evaluated the effect of Gallic Acid (GA) as a model phenolic compound on starch digestion kinetics carried out in vitro in a Rapid ViscoAnalyzer (RVA). The results showed that when GA was added before cooking of starch in order to promote starch-GA complexation, the rate of digestion of starch was similar to that of starch alone, and faster than when GA was added after cooking of starch. The results demonstrated that when GA was introduced after cooking of starch, GA inhibited α-amylase strongly and that inhibition increased with starch paste viscosity only for potato and wheat starches. No correlation was found between starch molecular characteristics and the inhibiting capacity of GA at different starch concentrations. However, the apparent influence of starch chain length distribution suggested that physical effects (such as the absorption of GA at the surface of the starch paste) may play a role in the capacity of GA to inhibit α-amylase.

Preparation, physicochemical characterization, and in vitro starch digestibility on complex of Euryale ferox kernel starch with ferulic acid and quercetin

The objective of the current research was to analyze the physicochemical, structural, and in vitro starch digestibility of Euryale ferox kernel starch (EFKS) in complexation with ferulic acid (FA) and quercetin (QR). XRD results have shown that FA and QR were attached to starch resulting crystalline complexes. SEM image showed a smooth, compact structure, indicating FA and QR assist in the reorganization of starch molecules. The 1H NMR spectra of starch-polyphenols complexes showed multiple additional peaks between 6.00 and 9.00 ppm due to the benzene ring and phenolic hydroxyl groups imparted from polyphenols. The shifting and emergence of the characteristic peak observed in the DSC thermogram confirmed that polyphenols were successfully attached to starch. Complexation alters colors, reduced swelling power, and increased the solubility of the complexes. Following the complexation of FA and QR, the content of resistant starch exhibited a significant rise, escalating from 7.69 % (control sample) to 49.39 % (10 % FA) and 54.68 % (10 % QR). This led to a notable reduction in the predicted glycemic index (pGI).The higher resistant starch in the complex is attributed due to the combined effects of the reordered structure of the complexes and the inhibitory activity of polyphenols against starch digestive enzymes. Therefore, EFKS-FA and EFKS-QR complex can be used as a functional ingredient for a low glycemic index food.

Fermentation of resistant starch from the starch-ferulic acid inclusion complex compared with high-amylose corn starch

Fermentation of resistant starch from the starch-ferulic acid inclusion complex, one representative of the starch-polyphenol inclusion complex, was investigated in this study. It was found that this complex-based resistant starch, high-amylose corn starch and the mixture of ferulic acid and high-amylose corn starch were mainly utilized at the initial 6 h as indicated by the gas production and pH. Besides, the supplement of high-amylose corn starch, the mixture and the complex promoted production of short-chain fatty acids (SCFAs), reduced the ratio of Firmicutes/Bacteroidetes (F/B) and selectively stimulated the proliferation of some beneficial bacteria. Specifically, the production of SCFAs in the control and high-amylose starch, mixture and complex groups was 29.33 mM, 140.82 mM, 144.12 mM, and 167.4 mM after fermentation for 48 h, respectively. Moreover, the F/B ratio of those groups was 1.78, 0.78, 0.8 and 0.69, respectively. These results suggested that the supplement of the complex-based resistant starch led to the most SCFAs and the lowest F/B ratio (P < 0.05). Moreover, the complex group had the largest abundance of beneficial bacteria, including Bacteroides, Bifidobacterium and Lachnospiraceae_UCG-001 (P < 0.05). In summary, the resistant starch from the starch-ferulic acid inclusion complex exhibited stronger prebiotic activity than high-amylose corn starch and the mixture.

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

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

Interactions between tea polyphenols and nutrients in food

Tea polyphenols (TPs) are important secondary metabolites in tea and are active in the food and drug industry because of their rich biological activities. In diet and food production, TPs are often in contact with other food nutrients, affecting their respective physicochemical properties and functional activity. Therefore, the interaction between TPs and food nutrients is a very important topic. In this review, we describe the interactions between TPs and food nutrients such as proteins, polysaccharides, and lipids, highlight the forms of their interactions, and discuss the changes in structure, function, and activity resulting from their interactions.

Effect of tea polyphenols on the physicochemical, structural and digestive properties of modified high amylose corn starch

In this study, starch-polyphenol complexes (CES-TPS complexes) were prepared using various ratios (0%, 2%, 4%, 6%, 8%, and 10%, based on starch) of tea polyphenols (TPS) and high amylose corn starch (HACS) pretreated with starch branching enzyme (SBE). It was aimed to determine the effects of TPS on the physicochemical and structural properties and digestibility of the CES-TPS complexes. Scanning electron microscopy and laser particle size analysis showed that the addition of a moderate amount of TPS will reinforce interaction force, while excessive TPS will cause a loose structural morphology, leading to an increase in starch particle size. Thermal property analysis indicated that SBE pre-treatment decreased T_O, T_P and T_C of HACS, and the gelatinization temperature was further reduced after adding TPS. The digestion of CES-TPS complexes was investigated using an Artificial Gut analyzer; the predicted glycemic index of starch samples decreased with the addition of a low concentration of TPS (2-6%), while there was a significant increment in the pGI of starch samples when a high concentration of TPS (8-10%) was added. XRD analysis showed that the relative crystallinity of the CES-TPS complexes further increased to 21.91% and then decreased to 19.38% with the increase of TPS concentration. The ratios of 1047/1022 cm^-1 presented the opposite trend to that determined by FT-IR.

Characterization of manganized soluble dietary fiber complexes from tigernut meal and study of the suppressive activity of digestive enzymes in vitro

In this study, manganized soluble dietary fiber (SDF-Mn(II)) was prepared from tigernut meal using a microwave solid-phase synthesis method with SDF. Microscopic morphological and structural analyses of SDF-Mn(II) were carried out using scanning electron microscopy, Fourier infrared spectroscopy, UV full-band scanning, X-ray diffraction, a thermal analyzer, gel permeation chromatography, and nuclear magnetic resonance, and its in vitro hypoglycemic activity was initially investigated. The results of these analyses revealed that the reaction of Mn(II) with SDF mainly involved hydroxyl and carbonyl groups, with the Nuclear magnetic resonance (NMR) analysis showing that specific covalent binding was produced and substitution was mainly carried out at the C₆ position. Moreover, compared with SDF, the SDF-Mn(II) complex exhibited a porous structure, red-shifted, and color-enhancing effects on the UV characteristic peaks, significantly increased crystallinity and decreased molecular weight, and improved thermal stability; in addition, SDF-Mn(II) afforded significantly enhanced inhibition of α-amylase and α-glucosidase and possesses good in vitro digestive enzyme inhibition activity.

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.

Starch, gallic acid, their inclusion complex and their effects in diabetes and other diseases-A review

Starch is the most important energy-providing component of food. It is useful for maintaining the structural and rheological consistency of food, ad thus, in turn, is responsible for maintaining the freshness of food. Polyphenols are present in plant products in huge amounts as secondary metabolites. Gallic acid, one of the potent plant polyphenols, has been reported to have excellent anti-inflammatory, antioxidative, anticarcinogenic, microbicidal, and antidiabetic properties. Till date, very few articles on the starch-polyphenol inclusion complex are present. Quite a few hypotheses have been proposed as to how the formation of an inclusion complex of starch with polyphenol can slower the digestion or the hydrolysis of starch. The efficient qualities of starch-polyphenol systems, such as reduced starch digestion, lower blood glucose and preserving food freshness, have formed a necessity for investigation in this area. The focus of this review centers on the recent research on starch-polyphenol interactions and starch-gallic acid inclusion complexes in native and extruded food systems, as well as how the production of these complexes can aid in the treatment of diseases, particularly diabetes mellitus.

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

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

Conversion of (poly)phenolic compounds in food fermentations by lactic acid bacteria: Novel insights into metabolic pathways and functional metabolites

Lactobacillaceae are among the major fermentation organisms in most food fermentations but the metabolic pathways for conversion of (poly)phenolic compounds by lactobacilli have been elucidated only in the past two decades. Hydroxycinnamic and hydroxybenzoic acids are metabolized by separate enzymes which include multiple esterases, decarboxylases and hydroxycinnamic acid reductases. Glycosides of phenolic compounds including flavonoids are metabolized by glycosidases, some of which are dedicated to glycosides of plant phytochemicals rather than oligosaccharides. Metabolism of phenolic compounds in food fermentations often differs from metabolism in vitro, likely reflecting the diversity of phenolic compounds and the unknown stimuli that induce expression of metabolic genes. Current knowledge will facilitate fermentation strategies to achieve improved food quality by targeted conversion of phenolic compounds.

Electron beam irradiation pretreatment enhances the formation of granular starch-phenolics complexes

Starch-phenolics complex generated by the interaction between starch and phenolic acids had improved characteristics than the native starch, but the efficient preparation of such complex is still challenging. In this study, we proposed a new method for the preparation of starch-phenolics complexes under the pretreatment of electron beam irradiation (EBI). Four structurally similar monomeric phenolic acids including gallic acid (GA), 3,4-Dihydroxy-5-methoxybenzoic acid (3MGA), syringic acid (SA) and vanillic acid (VA), which naturally existed in Tartary buckwheat (TB) seeds, were complexed with native and EBI-pretreated TB starch. The results showed that the complexation between starch and 3MGA was the strongest, more than 30 mg of 3MGA was complexed with 1 g of starch. The complexation did not affect the particle morphology and A-type structure of starch, but changed the crystal structure order and promoted the strength of hydrogen bond, which may lead to the formation of granular complex. EBI pretreatment can significantly promote the complexation by enhancing hydrogen bonds as indicated by a broader band at 3500 ∼ 3100 cm^-1 in the FT-IR spectra. In addition, EBI pretreatment helped to build a tighter bond and higher crystallinity, increase the particle size and iodine binding capacity, and decrease turbidity to inhibit retrogradation of starch. The ¹H NMR of complexes indicated that EBI pretreatment could provide more accessibility for starch to interact with phenolics by creating a spacious microenvironment for ¹H (α1 → 4). Above all, EBI pretreatment enhanced the formations of starch-phenolics complexes.

Efficient Retention and Complexation of Exogenous Ferulic Acid in Starch: Could Controllable Bioextrusion Be the Answer?

The starch-phenolics complexes are widely fabricated as functional foods but with low phenolics retention limited by traditional liquid reaction and washing systems. In this study, ferulic acid (FA, 5%) was exogenously used in the crystalline form, and it reacted with starch in a high-solid extrusion environment, which was simultaneously controlled by thermostable α-amylase (0-252 U/g). Moderate enzymolysis (21 or 63 U/g) decreased the degree of the starch double helix and significantly increased the FA retention rate (>80%) with good melting and distribution. Although there were no significantly strong chemical bonds (with only 0.17-2.39% FA bound to starch hydrolysate), the noncovalent interactions, mainly hydrogen bonds, van der Waals forces, and electrostatic interactions, were determined by ¹H NMR and molecular dynamics simulation analyses. The phased release of total FA (>50% in the stomach and ∼100% in the intestines) from bioextrudate under in vitro digestion conditions was promoted, which gives a perspective for handing large loads of FA and other phenolics based on starch carrier.

Comparative Evaluation of Hydrothermally Produced Rice Starch-Phenolic Complexes: Contributions of Phenolic Type, Plasma-Activated Water, and Ultrasonication

A thorough investigation of the viability of rice starch conjugation with three different phenolic compounds-gallic acid, sinapic acid, and crude Mon-pu (Glochidion wallichianum Muell Arg) (MP) extract-was conducted using a variety of developed methods which modified the techno-functionality and digestibility of the end product. With and without the aid of ultrasonication (US), phenolic compounds were complexed with hydrothermally pre-gelatinized rice starch prepared using distilled water or plasma-activated water (PAW). The in vitro digestibility, structural features, rheological and thermal properties, and in vitro antioxidant activity of starch-phenolic complexes were evaluated. The US-assisted starch-MP complex in water had the highest complexing index (CI) value (77.11%) and resistant starch (RS) content (88.35%), resulting in a more compact and stable ordered structure. In all complexes, XRD revealed a new minor crystalline region of V-type, which was stabilized by hydrogen bonding as defined by FTIR and H¹-NMR. Polyphenols caused a looser gel structure of starch, as imaged by a scanning electron microscope (SEM). Starch-phenolic complexes outperformed other complexes in terms of in vitro antioxidant activity. Gallic acid addition to starch molecules boosted DPPH scavenging activity, notably when synthesized in PAW regardless of US assistance, although having lower CI and RS values than the MP complex. Therefore, this research lays the groundwork for the efficient production of functional food ingredients based on rice starch and polyphenols.

Interactions between Phenolic Acids, Proteins, and Carbohydrates-Influence on Dough and Bread Properties

The understanding of interactions between proteins, carbohydrates, and phenolic compounds is becoming increasingly important in food science, as these interactions might significantly affect the functionality of foods. So far, research has focused predominantly on protein-phenolic or carbohydrate-phenolic interactions, separately, but these components might also form other combinations. In plant-based foods, all three components are highly abundant; phenolic acids are the most important phenolic compound subclass. However, their interactions and influences are not yet fully understood. Especially in cereal products, such as bread, being a nutritional basic in human nutrition, interactions of the mentioned compounds are possible and their characterization seems to be a worthwhile target, as the functionality of each of the components might be affected. This review presents the basics of such interactions, with special emphasis on ferulic acid, as the most abundant phenolic acid in nature, and tries to illustrate the possibility of ternary interactions with regard to dough and bread properties. One of the phenomena assigned to such interactions is so-called dry-baking, which is very often observed in rye bread.

Comparison of quercetin and rutin inhibitory influence on Tartary buckwheat starch digestion in vitro and their differences in binding sites with the digestive enzyme

Inhibitory effects of flavonoids on starch digestibility were well known, but the structural mechanism was not clear. This study was focused on the diverse effect of quercetin and rutin on digestibility of Tartary buckwheat starch. Results showed that quercetin and rutin reduced the starch digestion by altering starch structure in bound forms and inhibiting digestive enzyme activity in free forms simultaneously, and quercetin showed a stronger effect than rutin. Molecular docking and saturation transfer difference-nuclear magnetic resonance (STD-NMR) revealed different binding site of rutin from quercetin was due to its hydroxyl and hydrogen on the glycoside structure. Rutin interacted with enzymes mainly by CH and OH on the glycoside structure which induced steric hindrance and restricted the inhibitory effect of quercetin fraction. The glycoside structure weakened inhibition of rutin on digestive enzymes in free forms rather than influence its anti-digestive effects in bound forms with starch.

Co-extruded wheat/okra composite blends result in soft, cohesive and resilient crumbs rich in health-promoting compounds

This work investigates the partial solubilization of cell wall polysaccharides in okra flours and the changes in the profile of free and bound phenolics through twin-screw extrusion. The comparison between extruded wheat flour-native okra flour (EWF-OF) and extruded wheat flour-extruded okra flour (EWF-EOF) composite blends revealed that extrusion led to an increase of soluble dietary fiber from 7.76 to 10.02 g/100 g. Extrusion of okra also resulted in a significant increase of free and bound phenolic acids, the latter consisting mostly of ferulic acid, as well as the thermal degradation of free epigallocatechin, and the binding of a small portion of quercetin-3-O-glucoside likely to a carbohydrate fraction. Bread crumbs from EWF-EOF (at 15% replacement level) exhibited a significantly lower hardness and higher elasticity, cohesiveness and resilience (from 28.28 N, 0.94, 0.49 and 0.17 to 7.54 N, 0.99, 0.70 and 0.35, respectively), which closely resembled the textural attributes of wheat bread.

Antioxidant films and coatings based on starch and phenolics from Spondias purpurea L

The objective of this study was to prepare, for the first time, active films and coatings from fruit starch (SPFS) and phenolic stem bark extract (SBPE) from Spondias purpurea L. Starch film formulations were prepared with different SBPE contents (5-20 wt% on starch), then cast and dried into films. SBPE showed higher antioxidant activity and antimicrobial activity against both Gram-negative and Gram-positive bacteria. Chemical, morphological, thermal, optical, mechanical, and barrier properties were studied for SPFS-SBPE films. In general, the phenolic extract caused significant changes in starch films (especially when in excess), such as gradual reduction of elastic modulus and tensile strength, increased elongation, opacity, and thermal properties (e.g. glass transition and melting enthalpy). On the other hand, SBPE provided the films with active properties (antioxidant and UV-absorbing). Coatings were applied to minimally processed mangoes (MPM), which were stored for 10 days at 12 °C. SBPE-containing coatings provided better protective action, reducing the total color difference (∆E^⁎) and delaying the browning index (BI) during storage as well as reducing fungus attack. The active SPFS-SBPE films showed great potential as environmentally friendly active films and coatings.

Food Matrix Effects for Modulating Starch Bioavailability

As the prevalence of obesity and diabetes has continued to increase rapidly in recent years, dietary approaches to regulating glucose homeostasis have gained more attention. Starch is the major source of glucose in the human diet and can have diverse effects, depending on its rate and extent of digestion in the small intestine, on postprandial glycemic response, which over time is associated with blood glucose abnormalities, insulin sensitivity, and even appetitive response and food intake. The classification of starch bioavailability into rapidly digestible starch, slowly digestible starch, and resistant starch highlights the nutritional values of different starches. As starch is the main structure-building macroconstituent of foods, its bioavailability can be manipulated by selection of food matrices with varying degrees of susceptibility to amylolysis and food processing to retain or develop new matrices. In this review, the food factors that may modulate starch bioavailability, with a focus on food matrices, are assessed for a better understanding of their potential contribution to human health. Aspects affecting starch nutritional properties as well as production strategies for healthy foods are also reviewed, e.g., starch characteristics (different type, structure, and modification), food physical properties (food form, viscosity, and integrity), food matrix interactions (lipid, protein, nonstarch polysaccharide, phytochemicals, organic acid, and enzyme inhibitor), and food processing (milling, cooking, and storage).

Modulating Phenolic Bioaccessibility and Glycemic Response of Starch-Based Foods in Wistar Rats by Physical Complexation between Starch and Phenolic Acid

This study assessed the impact of caffeic and ferulic acid complexation with maize amylopectin or potato starch on glycemic parameters. In comparison to starch-phenolic mixtures, starch-phenolic complexes resulted in significant modification of phenolic bioaccessibility and cellular uptake (p < 0.05). In addition, glucose release from in vitro digestion of starch was modestly reduced in the complexes compared to native starch alone (21.2-26.8 versus 29.8-30.5 mM). Furthermore, intestinal glucose transport, assessed in Caco-2 cell monolayers, was not affected by the presence of complexes (82.4-124 versus 100% at 90 min). However, a reduced glycemic response was evident in a Wistar rat model, with significant reduction in 240 min of blood glucose area under the curve following oral administration of the potato starch-ferulic acid complex compared to native potato starch (26 170 ± 556 versus 28 951 ± 486 mg min dL^-1; p < 0.001). These alterations were attributed to complexation-induced resistant starch formation and phenolic entrapment, providing an alternative mechanistic approach to modulate glycemic properties of starch-based foods.