The effect of pH on the chemical and structural interactions between apple polyphenol and starch derived from rice and maize

Recent insights into functional, structural, and digestibility modifications of starch through complexation with polyphenols: A review

Starch-polyphenol complexes, formed through hydrogen bonding and hydrophobic interactions, significantly alter starch's functional, structural, and digestive properties. These complexes enhance thermal stability, reduce starch digestibility, and slow glucose release, offering potential benefits for glycemic control and functional food development. Polyphenols, including phenolic acids, flavonoids, tannins, lignans, and stilbenes, form inclusion and non-inclusion complexes with amylose, potentially increasing resistant starch (RS) content and lowering the glycemic index of foods, which may benefit individuals with diabetes. However, the effectiveness of these complexes depends on factors such as polyphenol structure, starch type, and processing conditions. In some cases, processing may degrade polyphenols, potentially enhancing starch digestibility. Future research should focus on understanding the underlying mechanisms, validating health benefits through in vivo studies, and optimizing processing techniques for functional foods targeting glycemic control. This will maximize the potential of starch-polyphenol complexes in developing healthier, more sustainable food solutions.

Insights into folic acid functionalization of self-assembled octenyl succinic anhydride starch micelles towards targeted delivery of selenium nanoparticles

Selenium nanoparticles (SeNPs) exhibit significant potential in antitumor therapy. However, challenges such as aggregation and lack of targeting capability limit their application. Herein, we developed selenium-loaded octenyl succinic anhydride starch (OSAS) micelles functionalized with folic acid (FA) for targeted tumor delivery. The FA-OSAS-SeNPs were synthesized through self-assembly, incorporating SeNPs into FA-conjugated OSAS micelles. Fourier Transform Infrared (FTIR) spectroscopy and UV-visible spectrophotometry confirmed the successful synthesis of FA-OSAS-SeNPs. The nanoparticles exhibited an average size of 131.66 ± 7.88 nm and a zeta potential of -19.54 ± 0.33 mV, with encapsulation efficiency and drug loading capacity of approximately 87.28 % and 8.96 %, respectively. FA-OSAS-SeNPs demonstrated good stability across various conditions, including different dilution ratios, temperatures, pH levels, and ionic strengths. In vitro studies showed that FA-OSAS-SeNPs exhibited significant targeted inhibitory effects on cervical cancer (HeLa) cells and markedly increased intracellular ROS levels, inducing apoptosis. This study presents a novel and effective strategy for targeted SeNPs delivery systems in tumor therapy, offering a valuable reference for future development of nanomaterials for clinical applications in cancer treatment.

Sweetening with Agavins: Its Impact on Sensory Acceptability, Physicochemical Properties, Phenolic Composition and Nutraceutical Potential of Oak Iced Tea

Oak infusions enriched with agavins may offer nutraceutical benefits in the development of iced teas. This study evaluated infusions of Quercus sideroxyla and Quercus eduardii leaves formulated with different concentrations of agavins (0, 2, 6, and 10%), analyzing their physicochemical and sensory properties, chemical stability, and antioxidant capacity. The incorporation of agavins resulted in substantial modifications to physicochemical parameters, including pH, titratable acidity, and soluble solids, thereby enhancing product stability and consistency. Notable distinctions were observed between the two species with respect to their acidogenic response and soluble solid concentration. Interactions between agavins and phenolic compounds, as discerned by UPLC-PDA-ESI-MS/MS and FT-IR, exerted a significant influence on bioactivity of the phenolic constituents, thereby affecting the nutraceutical potential of the infusions. These interactions, facilitated by hydrogen bonds, led to reduction in phenolic acids, such as quinic acid (↓ 43%), and alteration in antioxidant capacity at high concentrations of agavins. The findings underscore the significance of meticulously designing balanced formulations that optimize chemical stability, functionality, and sensory acceptance, thereby ensuring the quality of the final product.

Modulation of starch-polyphenol complex thermal stability and antioxidant activity: The role of polyphenol structure

Polyphenols are closely related to human health, but thermal treatment causes the loss of polyphenol activity. Complexation between amylose and polyphenol prevents oxidation and degradation of polyphenols during thermal treatment. And the functional properties of the complex are affected by the polyphenol backbone. Therefore, this study compared the complexation between pre-formed V-amylose (V6a) and polyphenols with different backbones (C6-C1, C6-C3, and C6-C3-C6). Specifically, a non-inclusion complex was formed between V6a and PHBA through intermolecular hydrogen bonding, whereas p-coumaric acid (PCA, C6-C3 backbone) and 6-hydroxyflavone (HF, C6-C3-C6 backbone) formed V-type inclusion complexes with V6a. In addition, V6a-PCA possessed greater relative crystallinity (42.70 %), higher thermal stability (136.2 °C), higher encapsulation efficiency (22.8 %), and stronger antioxidant activity (2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity = 62.80 %). Finally, the molecular dynamic simulation corroborated the effect of the polyphenol backbone on the complex type. This study suggested that C6-C3 backbone polyphenols facilitated the formation of inclusion complexes with V-amylose compared to hydrophilic C6-C1 backbone polyphenols and C6-C3-C6 backbone polyphenols. V-type inclusion complexes are effective encapsulation carriers, which can be used in the future to enhance the bioactivity of polyphenols in food processing.

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.

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.

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.

Chemotherapeutics-Loaded Poly(Dopamine) Core-Shell Nanoparticles for Breast Cancer Treatment

Chemophotothermal therapy is an emerging treatment of metastatic and drug-resistant cancer anomalies. Among various photothermal agents tested, poly(dopamine) provides an excellent biocompatible alternative that can be used to develop novel drug delivery carriers for cancer treatment. This study explores the synthesis of starch-encapsulated, poly(dopamine)-coated core-shell nanoparticles in a one-pot synthesis approach and by surfactant-free approach. The nanoparticles produced are embellished with polymeric stealth coatings and are tested for their physiologic stability, photothermal properties, and drug delivery in metastatic triple-negative breast cancer cell (TNBC) lines. Our results indicate that stealth polymer-coated nanoparticles exhibit superior colloidal stability under physiologic conditions, and are excellent photothermal agents, as determined by the increase in temperature of solution in the presence of nanoparticles, upon laser irradiation. The chemotherapeutic drug-loaded nanoparticles also showed concentration-dependent toxicities in TNBC and in a brain metastatic cell line. SIGNIFICANCE STATEMENT: This study develops, for the first time, biocompatible core-shell nanoparticles in a template-free approach that can serve as a drug delivery carrier and as photothermal agents for cancer treatment.

A review: Effects of microbial fermentation on the structure and bioactivity of polysaccharides in plant-based foods

Fermented plant-based foods that catering to consumers' diverse dietary preferences play an important role in promoting human health. Recent exploration of their nutritional value has sparked increasing interest in the structural and bioactive changes of polysaccharides during fermentation, the essential components of plant-based foods which have been extensively studied for their structures and functional properties. Based on the latest key findings, this review summarized the dominant fermented plant-based foods in the market, the involved microbes and plant polysaccharides, and the corresponding modification in polysaccharides structure. Further microbial utilization of these polysaccharides, influencing factors, and the potential contributions of altered structure to the functions of polysaccharides were collectively illustrated. Moreover, future research trend was proposed, focusing on the directional modification of polysaccharides and exploration of the mechanisms underlying structural changes and enhanced biological activity during fermentation.

Effects of ultrasound-induced V-type rice starch-tannic acid interactions on starch in vitro digestion and multiscale structural properties

V-type starch-polyphenol complexes, known for their improved physicochemical properties compared to native starch, are challenging to form efficiently. In this study, the effects of tannic acid (TA) interaction with native rice starch (NS) on digestion and physicochemical properties were investigated using non-thermal ultrasound treatment (UT). Results showed the highest complexing index for NSTA-UT3 (∼ 0.882) compared to NSTA-PM (∼0.618). NSTA-UT complexes reflected the V6I-type complex having six anhydrous glucose per unit per turn with peaks at 2θ = 7°, 13°, and 20°. The maxima of the absorption for iodine binding were suppressed by the formation of V-type complexes depending on the concentration of TA in the complex. Furthermore, rheology and particle size distributions were also affected by TA introduction under ultrasound, as revealed by SEM. XRD, FT-IR, and TGA analyses confirmed V-type complex formation for NSTA-UT samples, with improved thermal stability and increased short-range ordered structure. Ultrasound-induced addition of TA also decreased the hydrolysis rate and increased resistant starch (RS) concentration. Overall, ultrasound processing promoted the formation of V-type NSTA complexes, suggesting that tannic acid could be utilized for the production of anti-digestion starchy foods in the future.

Phenolic mapping and associated antioxidant activities through the annual growth cycle of sugar maple leaves

Concentrations of antioxidant components (analyzed by HPLC-UV) and antioxidant attributes (assayed by radical scavenging and non-radical redox potential methods) of sugar maple leaves (SML) from different harvesting times were investigated. Moreover, measurements of colorimetry, SEM, and FTIR spectroscopy-based characterization of leaves composition, throughout the growth cycle, were performed. Results showed that the antioxidant activities of SML are strongly correlated with phenolic contents and significantly (p < 0.05) varied with harvesting time where minimum amount of total phenolics (105.67 ± 13.16 mg GAE/g DM) and total flavonoids (3.27 ± 0.26 mg CTE/g DM) were found to be concentrated in Fall leaves. The absorption bands obtained from FTIR spectra revealed the presence of functional groups that have great significance towards the antioxidant activity of SML. Principal component analysis revealed that biosynthesis of maximum phenolic compounds in SML mostly occurs during the leaf expansion and growth phases. The obtained data provided a better understanding towards the effect of harvesting time on the phenolic mapping of SML in favor of its valorization into functional food ingredients.

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.

The effects of pH and iron ions on the mechanical properties of pea starch hydrogels

In this study, the network strength of starch hydrogels was improved by adjusting the pH value (3-11.5) and adding iron ions (Fe3+), and the mechanical properties and swelling properties of the hydrogels were improved. The complex modulus of the starch hydrogel with a pH value of 11.5 and containing Fe3+ was above 3400 Pa. SEM showed that the hydrogel structure became more compact with the increase of pH value. In addition, the hardness of the hydrogel increased from 50.29 g at pH 3.0 to 215.1 g at pH 11.5, while the addition of 0.5 mol/L Fe3+ at pH 11.5 promoted a further hardness increase to 301.8 g. Moreover, the swelling rate of the hydrogel decreased from 670.2 % at pH 7.0 to 464.4 % at pH 11.5, and the addition of 0.5 mol/L Fe3+ further decreased the swelling rate to 191.8 %. Overall, the results indicate that the mechanical properties of starch hydrogels can be improved by making simple adjustments to the pH and the iron ion concentrations.

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

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