Both alkyl chain length and V-amylose structure affect the structural and digestive stability of amylose-alkylresorcinols inclusion complexes

Highly sensitive ratiometric fluorescence detection of dibutyl phthalate in liquor and water using bio-based fluorescent molecularly imprinted polymers

A novel fluorescent molecularly imprinted polymer (DBP-FMIPs) was designed and prepared for the selective detection of dibutyl phthalate (DBP) in food samples. This was achieved using inclusion complexes formed between short amylose and DBP as precursors, with tetrafluoroterephthalonitrile, which possesses an electron-donor-acceptor type dipolar structure within a compact benzene backbone, serving as a crosslinking agent and fluorescent readout signal. DBP-FMIPs exhibit excellent fluorescence stability and high selectivity, with a response time of less than 3 min for DBP. Based on the blue-green fluorescence emitted by DBP-FMIPs (λem = 500 nm), this material provided the response signal, while the red-emitting carbon dots(R-CDs, λem = 680 nm) were used as an internal reference, constructing a ratiometric fluorescence probe (R-CDs/DBP-FMIPs). The fluorescence intensity ratio (I500/I680)0/(I500/I680) exhibited a linear response to DBP within a concentration range of 0.020-20 mg L-1, with a detection limit as low as 4.5 μg L-1, and its fluorescence color shifted from blue to red. The fluorescent probe was successfully applied for detecting DBP in liquor and drinking water samples, achieving recoveries of 88-107 % and a relative standard deviation of 1.1-6.4 %. This preparation method can also be adapted for synthesizing FMIPs targeting other hydrophobic compounds. Additionally, the developed ratiometric fluorescence probe shows great potential for the selective and visual detection of phthalates in complex samples.

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.

In vitro hydrolysis of V-type starch inclusion complexes of alkyl gallates: the controlled two-step release behavior of gallic acid and its beneficial effect on glycemic control

The heat treatment method was used to synthesize starch inclusion complexes from starch and short-chain alkyl gallates (a typical representative of phenololipids), such as butyl gallate, propyl gallate, ethyl gallate and methyl gallate. In an everted rat gut sac model, HPLC-UV analysis revealed that the released alkyl gallates from inclusion complexes were degraded to produce gallic acid. Gallic acids (0.009455-0.014160 nmol min-1) and alkyl gallates (0.2695-0.9441 nmol min-1) were both able to pass through intestinal membranes. After transmembrane transfer, alkyl gallates could also be hydrolyzed to produce gallic acid (1.947 × 10-5-2.290 × 10-5 min-1). It was evident that such an inclusion complex demonstrated superior dual sustained-release characteristics for phenolic compounds. Meanwhile, starch inclusion complexes can also slow down starch digestion by raising resistant starch (from 12.2% to 27.2-46.0%) and lowering rapidly digestible starch (from 51.2% to 22.2-51.2%), according to a glucose oxidase-peroxidase analysis. The delayed digestion behavior of starch in inclusion complexes is very beneficial for blood glucose control. Thus, our work effectively established a theoretical foundation for modifying the dual sustained-release behavior of phenolic compounds and the retardation of starch digestion by adjusting the carbon-chain length in starch inclusion complexes.

Insights into the improved cold-water solubility and digestibility of alkaline-alcohol modified cassava starch: A discussion from the perspective of fine structure

Multi-objective optimization of starch for higher solubility and lower glycemic index is a challenge. In this study, we investigated the molecular structure evolution of cold water-soluble starch (CWS) and its correlation mechanism with solubility and digestibility by alkali-alcohol treatment of cassava starch. As NaOH concentration increased, the average molecular size of CWS gradually decreased, and the medium-long amylose (AM) chains (X ~ 1000-10,000) decreased sharply. The breakage of long starch chains could reveal more hydroxyl groups, increasing the opportunity to form hydrogen bonds with water molecules and thus increasing solubility up to 77.19 %. The ordered structure of starch was gradually destroyed, further reducing the gelatinization enthalpy and thus promoted starch swelling and gelatinization at lower temperatures. Compared to pregelatinized starch, the in vitro digestion fit showed that the estimated glycemic index of CWS was lower by about 10 %. The above multi-scale results could be found that the CWS still retained higher content of medium-long AM chains, which promoted stable and ordered structure of the starch chains, effectively impeding the penetration of digestive enzymes, whereas the relatively intact granule structure could inhibit the diffusion of digestive enzymes. This study could hold future potential for application in the field of starch-based instant convenience 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.

Rice Starch Chemistry, Functional Properties, and Industrial Applications: A Review

Starch is among the most abundant natural compounds in nature after cellulose. Studies have shown that the structure and functions of starch differ extensively across and among botanical types, isolation procedures, and climate factors, resulting in starch with significant variations in its chemical, physical, morphological, thermal, and functional characteristics. To enhance its beneficial properties and address inherent limitations, starch is modified through various techniques, resulting in significant alterations to its chemical and physical characteristics. These structural modifications impart considerable technological and industrial versatility. In the food sector, modified starch serves as a thickener, shelf-life extender, fat replacer, texture modifier, gelling agent, and stabilizer. In non-food applications, it functions as a sizing agent, binder, disintegrant, absorbent, and adhesive and is employed in construction as a sealant and to improve material bonding strength. The demand for modified starch has surpassed that of its native counterpart, reflecting its growing market value and the industry's interest in products with novel functional attributes and enhanced value. This study focuses on rice starch, highlighting its structure and composition and their impact on physicochemical properties and functionality. Additionally, it examines the enhancement of its techno-functional characteristics, achieved through various modification processes.

Underlying mechanism of electrospun starch-based nanofiber mats to adsorb the key off-odor compounds of oyster peptides

The solid-phase adsorption principles and fundamental mechanism of isobutyric acid, 1-octen-3-ol, and octanal (three key off-odor compounds of oyster peptides) were explored using electrospun octenyl succinylated starch-pullulan (OSS-PUL) nanofiber mat. The nanofiber mats had selective adsorption behaviors as indicated by the selective adsorption rates of isobutyric acid, 1-octen-3-ol, and octanal, which were 94.96%, 85.03%, and 65.36%. The contents of the II-type inclusion complexes (ICs) formed with the nanofiber mats by the three off-odor compounds mentioned above were significantly different. The mean fiber diameter of the octanal/nanofiber mat IC with the highest content of II-type IC was significantly decreased (p < 0.05). In contrast, the isobutyric acid/nanofiber mat IC did not significantly change. The findings suggested that nanofiber mats interacted most strongly with octanal and weakly with isobutyric acid. This study will provide the theoretical foundation for deodorizing aquatic products using electrospun starch-based nanofiber mats.

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.

Structure and functionality of surface-active amylose-fatty amine salt inclusion complexes

Novel value-added starch-based materials can be produced by forming amylose inclusion complexes (AIC) with hydrophobic compounds. There is currently little research on AIC use as polymeric emulsifiers, particularly for AIC with fatty amine salt ligands. This work evaluated AIC emulsifiers by studying the structure and functionality of AIC composed of high amylose corn starch and fatty amine salts (10-18 carbons, including a mixture simulating vegetable oil composition) produced via steam jet cooking. X-ray scattering verified successful AIC formation, with peaks located near 7.0°, 12.8° and 19.9° 2θ. AIC were easily dispersed in water (80-85 °C) and remained in suspension at room temperature for weeks, unlike the uncomplexed ligands or starch. AIC were highly effective emulsifying agents, with emulsifying activity indexes of 213-229 m2g-1 at pH 5, and zeta potentials, a measure of electrostatic repulsion, as high as 43.4 mV. AIC dispersions had surface tension ranging from 24 to 41 mN/m and displayed surface-active properties superior to amylose complexes formed from fatty acid salts and competitive with common starch-based emulsifiers. These findings demonstrate that fatty amine salt AIC are effective emulsifiers that can be made from low-cost sources of fatty amine salts, such as vegetable oil derivatives.

Starch-guest complexes interactions: Molecular mechanisms, effects on starch and functionality

Starch is a natural, abundant, renewable and biodegradable plant-based polymer that exhibits a variety of functional properties, including the ability to thicken or gel solutions, form films and coatings, and act as encapsulation and delivery vehicles. In this review, we first describe the structure of starch molecules and discuss the mechanisms of their interactions with guest molecules. Then, the effects of starch-guest complexes on gelatinization, retrogradation, rheology and digestion of starch are discussed. Finally, the potential applications of starch-guest complexes in the food industry are highlighted. Starch-guest complexes are formed due to physical forces, especially hydrophobic interactions between non-polar guest molecules and the hydrophobic interiors of amylose helices, as well as hydrogen bonds between some guest molecules and starch. Gelatinization, retrogradation, rheology and digestion of starch-based materials are influenced by complex formation, which has important implications for the utilization of starch as a functional and nutritional ingredient in food products. Controlling these interactions can be used to create novel starch-based food materials with specific functions, such as texture modifiers, delivery systems, edible coatings and films, fat substitutes and blood glucose modulators.

Bottom-Up Synthesized Glucan Materials: Opportunities from Applied Biocatalysis

Linear d-glucans are natural polysaccharides of simple chemical structure. They are comprised of d-glucosyl units linked by a single type of glycosidic bond. Noncovalent interactions within, and between, the d-glucan chains give rise to a broad variety of macromolecular nanostructures that can assemble into crystalline-organized materials of tunable morphology. Structure design and functionalization of d-glucans for diverse material applications largely relies on top-down processing and chemical derivatization of naturally derived starting materials. The top-down approach encounters critical limitations in efficiency, selectivity, and flexibility. Bottom-up approaches of d-glucan synthesis offer different, and often more precise, ways of polymer structure control and provide means of functional diversification widely inaccessible to top-down routes of polysaccharide material processing. Here the natural and engineered enzymes (glycosyltransferases, glycoside hydrolases and phosphorylases, glycosynthases) for d-glucan polymerization are described and the use of applied biocatalysis for the bottom-up assembly of specific d-glucan structures is shown. Advanced material applications of the resulting polymeric products are further shown and their important role in the development of sustainable macromolecular materials in a bio-based circular economy is discussed.

High selectivity molecularly imprinted polymer based on short amylose as bio-based functional monomers for selective extraction of λ-cyhalothrin

Nowadays, the development of sustainable molecularly imprinted polymers (MIPs) with high selectivity is still challenging due to the limitations of bio-based functional monomers. In this study, the highly selective and porous MIPs (LC-TMIPs) were designed and prepared on short amylose (SAM) as bio-based functional monomers, λ-cyhalothrin (LC) as a template molecule, and tetrafluoroterephthalonitrile as a rigid crosslinking agent. Static, dynamic, and selective adsorption experiments were conducted to investigate the adsorption performance. The results indicated that, compared to MIPs prepared using epichlorohydrin as flexible crosslinking agents, LC-TMIPs exhibited higher imprinting factor (3.93), selectivity (5.78), and adsorption capacity (35.79 mg g-1), as well as faster adsorption/desorption kinetics. The LC-TMIPs were used as sorbents for the selective determination of LC in both apple and cucumber samples by high-performance liquid chromatography. Under the optimal extraction conditions, the recoveries of the method reached 92.1-106.1 %, with a linear range of 1.5-30 ng g-1 and a detection limit of 0.5 ng g-1. The proposed preparation method of LC-TMIPs is expected to open a new way to prepare highly selective and sustainable MIPs for hydrophobic compounds.

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.

Interaction of high amylose corn starch with polyphenols: Modulating the stability of polyphenols with different structure against thermal processing

Polyphenols are known to undergo thermal degradation and their bioactivity is reduced. In this study, the thermal degradation of polyphenols was modulated by the complexation between polyphenols and high amylose corn starch (HACS). The inclusion complex between ferulic acid with hydrophobic group methoxy and HACS had the highest encapsulation efficiency (EE = 26.15 %), loading efficiency (LE = 2.38 %) and thermal stability (DPPH radical scavenging activity was reduced by only 5.99 % after baking). After complexing with HACS, protocatechuic acid with ortho-position hydroxyl group had a higher encapsulation rate and thermal stability than 3, 5-dihydroxybenzoic acid with meta-position hydroxyl. In addition, soy isoflavone with the higher logarithmic value of octanol-water partition coefficient (Log P = 3.66) resulted in higher encapsulation rate and thermal stability than naringenin (Log P = 2.11). The results suggest that the complexation between polyphenols and starch protects the bioactivity of polyphenols and improves the processing suitability of polyphenols.

Gallic acid forms V-amylose complex structure with starch through hydrophobic interaction

This study aimed to investigate the role of amylose and amylopectin in the formation of starch-polyphenol complex and elucidate the interaction mechanisms. Gallic acid (GA) was used to complex with maize starch with various amylose contents. Results showed GA formed V-type crystals with normal maize starch (NMS) and high amylose maize starch (HAMS), while higher relative crystallinity was exhibited in HAMS-GA complexes than NMS counterparts. Molecular structure analysis revealed more amylose in GA-starch complexes than in treated starch counterparts without GA, and this was more apparent in HAMS than NMS, implying amylose is preferred to complex with GA than amylopectin. FTIR detected higher R1047/1022 value in starch-GA complexes than their starch counterparts without GA, suggesting increased short-range ordered structrure of complexes. Typical signatures of hydrophobic interactions were further revealed by isothermal titration calorimetry, indicating the complexation of GA to starch is mainly through hydrophobic bonds. More binding sites were observed for HAMS (72.50) than NMS (11.33), which proves the preferences of amylose to bind with GA. Molecular dynamics simulated the complexation of GA to amylose, and confirmed hydrophobic bond is the main interaction force. These findings would provide guidance for precise design and utilization of starch-polyphenol complexes in functional foods.

Study on the improvement of complexation efficiency and anti-digestibility of phenolic acids based on electrospun starch fibers

Phenolic acids can be encapsulated by starch electrospun fibers, and the structural and functional properties of the electrospun fiber are affected by the chemical structure of phenolic acid. In this study, five phenolic acids (protocatechuic acid (PA), p-hydroxybenzoic acid (PHBA), p-coumaric acid (PCA), ferulic acid (FA), and caffeic acid (CA)) were chosen to prepare electrospun fibers with high amylose corn starch (HACS) at different voltages. Morphology and complexation efficiency results revealed that the electrospun fibers prepared at 21.0 kV were smooth and continuous with high encapsulation efficiency (EE) and loading efficiency (LE). The chemical structure of phenolic acid played an important role in the structure and properties of electrospun fibers by influencing the complexation of HACS with phenolic acids and the inhibitory effect of amylase. As a result, electrospun fibers containing HACS-CA inclusion complex had higher relative crystallinity (25.47 %), higher thermal degradation temperatures (356.17 °C), and the strongest resistance to digestion (starch digestive ratio = 22.98 %). It is evident that electrospun fibers containing HACS-phenolic acid inclusion complexes not only achieve high phenolic acid complexation efficiency, but also resist the effects of the gastric and small intestinal environment on phenolic acids, thereby improving the bioaccessibility of phenolic acids.

A highly efficient molecularly imprinted fluorescence sensor for assessing whole wheat grains by the rapid and sensitive detection of alkylresorcinols

To differentiate whole wheat foods from refined wheat foods is still challenging grain industry and confusing consumers. Alkylresorcinols (ARs), as biomarkers of whole wheat grains, can serve for assessing the authenticity of whole wheat foods. Herein, a highly efficient fluorescence sensing platform (CDs@MIP) for rapid and sensitive analysis of ARs was explored, using carbon dots (CDs) as fluorophores and 5-heneicosylresorcinol (C21:0 AR) as template molecules embedded in a molecularly imprinted polymer (MIP) coating. Benefiting from the specific cavities in the probe and a photo-induced electron transfer effect, the fluorescence intensity of CDs@MIP was significantly quenched in the presence of C21:0 AR, exhibiting a superior binding efficiency and selectivity. As a result, the fabricated optical sensor delivered a wide linear range of C21:0 AR from 0.015 to 60 μg mL-1 with an ultralow detection limit of 4 ng mL-1. It was noteworthy that the sensor was successfully applied for the rapid detection of C21:0 AR in commercial whole-wheat foods as well as visualization analysis on the test paper, comprehensively validating the practicality and efficacy of CDs@MIP based fluorescence assay. The study provides a rapid and sensitive detection method of C21:0 AR, paving a new way for guiding grain industry to effectively qualify the authenticity and to quantify the content of whole wheat in wheat-based foods.