Detection of a novel three component complex consisting of starch, protein, and free fatty acids

New insights into starch, lipid, and protein interactions - Colon microbiota fermentation

Starch, lipids, and proteins are essential biological macromolecules that play a crucial role in providing energy and nutrition to our bodies. Interactions between these macromolecules have been shown to impact starch digestibility. Understanding and controlling starch digestibility is a key area of research. Investigating the mechanisms behind the interactions of these three components and their influence on starch digestibility is of significant practical importance. Moreover, these interactions can result in the formation of resistant starch, which can be fermented by gut microbiota in the colon, leading to various health benefits. While current research has predominantly focused on the digestive properties of starch in the small intestine, there is a notable gap in understanding the colonic microbial fermentation phase of resistant starch. The benefits of fermentation of resistant starch in the colon may outweigh its glucose-lowering effect in the small intestine. Thus, it is crucial to study the fermentation behavior of resistant starch in the colon. This paper investigates the impact of interactions among starch, lipids, and proteins on starch digestion, with a specific focus on the fermentation phase of indigestible carbohydrates in the colon. Furthermore, valuable insights are offered for guiding future research endeavors.

New Insight into the Effects of Endogenous Protein and Lipids on the Enzymatic Digestion of Starch in Sorghum Flour

The effects of endogenous lipids and protein in sorghum flour on starch digestion were studied following the depletion of lipids and/or protein and after the reconstitution of separated fractions. The removal of protein or lipids moderately increases the digestibility of starch in raw (uncooked) sorghum flour to values close to those for purified starch. Rapid Visco Analyzer data (as a model for the cooking process) show that cooked sorghum flours with lipids have a lower starch digestibility than those without lipids after RVA processing, due to the formation of starch-lipid complexes as evidenced by their higher final viscosity and larger enthalpy changes. Additionally, the formation of a starch-lipid-protein ternary complex was identified in cooked sorghum flour, rather than in a reconstituted ternary mixture, according to the unique cooling stage viscosity peak and a greater enthalpy of lipid complexes. After heating, the sorghum flour showed a lower digestibility than the depleted flours and the reconstituted flours. The results indicate that the natural organization of components in sorghum flour is an important factor in facilitating the interactions between starch, lipids, and protein during RVA processing and, in turn, reducing the starch digestion.

Lecithin enhances the complexation between pea starch and fatty acids in aqueous system, and affects the starch's structure and enzymatic hydrolysis

This paper investigates a newly found effect of lecithin on the complexation between starch and saturated fatty acids. Rapid visco analysis showed that adding lecithin to the pea starch-fatty acid mixtures resulted in a viscosity peak during the setback stage of the pasting curve. Subsequent differential scanning calorimetry showed that pea starch-fatty acid-lecithin systems formed more V-type structures than pea starch-fatty acid complexes. X-ray diffraction and Fourier transform infrared spectroscopy indicated the addition of lecithin developed the long-range and short-range order of the V-complexes. Small-angle X-ray scattering showed the ternary system had a more compact stack in nano-scale and smaller D bragg than the binary complex. In vitro enzymatic hydrolysis revealed higher hydrolysis resistance of ternary systems compared to binary complexes. The results of this research provide a mechanism for modifying starch-lipid complexes and contribute to scientific understanding of food ingredient interactions.

New Perspectives on Food Matrix Modulation of Food Allergies: Immunomodulation and Component Interactions

Food allergy is a multifactorial interplay process influenced not only by the structure and function of the allergen itself but also by other components of the food matrix. For food, before it is thoroughly digested and absorbed, numerous factors make the food matrix constantly change. This will also lead to changes in the chemistry, biochemical composition, and structure of the various components in the matrix, resulting in multifaceted effects on food allergies. In this review, we reveal the relationship between the food matrix and food allergies and outline the immune role of the components in the food matrix, while highlighting the ways and pathways in which the components in the food matrix interact and their impact on food allergies. The in-depth study of the food matrix will essentially explore the mechanism of food allergies and bring about new ideas and breakthroughs for the prevention and treatment of food allergies.

Prior interaction of protein and lipid affects the formation of ternary complexes with starch

The effects of prior interaction between β-lactoglobulin (βLG) and lauric acid (LA) on their formation of ternary complexes with wheat starch (WS) was studied. Firstly, the interaction between βLG and LA after they were heated at different temperatures between 55 and 95 °C was characterized by fluorescence spectroscopy and molecular dynamics simulation. This showed that a greater degree of βLG-LA interaction occurred after heating at higher temperatures. The WS-LA-βLG complexes formed subsequently were analyzed by differential scanning calorimetry, X-ray diffraction, Raman and FTIR spectroscopy, which showed that as interaction of βLG and LA increased there was an inhibitory action on the formation of ternary complex with WS. Hence, we conclude that there is competition in the ternary systems between the protein and starch to interact with the lipid, and that stronger interaction of the protein and lipid may hinder the formation of ternary complexes with starch.

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

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

Effect of the Amylose Nanoscale Polymerization Index on the Digestion Kinetics and Mechanism of Recombinant Chinese Seedless Breadfruit Starch Triadic Complexes

The demand for multicomponent foods to meet human energy and nutritional needs has been increasing; however, few studies have addressed the theoretical basis for their preparation. We investigated the effect of the nanoscale polymerization index (DPw) of amylose on the logarithm of slope plot-based kinetics and the mechanism of digestion of starch-lauric acid-β-lactoglobulin protein complexes. Amylose from each of the five Chinese seedless breadfruit species was mixed with breadfruit amylopectin with the highest resistant starch (RS) content to form starch ternary complexes with various amylose DPws. All five complexes exhibited V-type crystalline diffraction and rod-like molecular configuration. Characteristic X-ray diffraction peaks and Fourier transform-infrared spectra of the ternary complexes revealed similar molecular configurations. As the amylose DPw increased, the complexing index, relative crystallinity, short-range order, weight-average molar mass, molecular density index, gelatinization temperature, decomposition temperature, RS, slowly digestible starch (SDS), and speed rate constants at the second hydrolysis stage (k₂) increased, whereas the semicrystalline lamellae thickness, mass fractal structure parameter, average characteristic crystallite unit length, radius of gyration, fractal dimension and cavities of granule surface microstructure, final viscosity, interval speed rate from SDS to RS, equilibrium concentration, and glycemic index decreased. The digestion kinetics exhibited highly significant variation according to the physiochemical properties and multiscale supramolecular structure (r > 0.99 or r < -0.99, p < 0.01). Together, these results identify amylose DPw as an important structural factor that markedly affects the kinetics and mechanism of ternary complex digestion and provide a new theoretical direction for the production of starch-based multicomponent foods.

Mechanisms Underlying the Formation of Amylose- Lauric Acid-β-Lactoglobulin Complexes: Experimental and Molecular Dynamics Studies

The aim of the present study was to reveal the mechanisms underlying the formation of ternary complexes with a model system of amylose (AM), lauric acid (LA), and β-lactoglobulin (βLG) using experimental studies and molecular dynamics (MD) simulations. Experimental analyses showed that hydrophobic interactions and hydrogen bonds contributed more than electrostatic forces to the formation of the AM-LA-βLG complex. MD simulations indicated that interactions between AM and βLG through electrostatic forces and hydrogen bonds, and to a less extent van der Waals forces, and interactions between AM and LA through van der Waals forces, were mostly responsible for complex formation. The combination of experimental results and MD simulations has provided new mechanistic insights and led us to conclude that hydrophobic interactions, van der Waals forces between AM and LA, and van der Waals forces and hydrogen bonds between AM and βLG were the main driving forces for the formation of the AM-LA-βLG complex.

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

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

Influence of Hofmeister anions on structural and thermal properties of a starch-protein-lipid nanoparticle

A self-assembled soluble nanoparticle, composed of common food biopolymers (carbohydrate, protein) and lipid, was previously reported by our laboratory. Although carrying capacity of valuable small molecules was demonstrated, physical functional properties are also important. Given the stabilization or destabilization characteristics of Hofmeister anion on macromolecular structures, mainly on proteins, here, we investigated the effects of different sodium salts composed of different Hofmeister anions on the structural and thermal properties of these self-assembled nanoparticles for improved functionalities. The salts were added into the mixture that was prepared in a diluted system during nanoparticle formation. Increased concentration of kosmotropic anions, in contrast to the chaotropic anion tested, resulted in nanoparticles with higher molar mass, hydrodynamic radius, and molecular density with more compact arrangement. The nanoparticles produced in presence of kosmotropic anions dissociated at higher temperatures and required higher enthalpies compared to the control sample. Spherical nanoparticles were formed for the kosmotropes with shear thinning behavior, contrary to rod-like nanoparticles for the chaotrope with near-Newtonian behavior. These findings help to gain an understanding of the effect of altering environmental conditions on the nanoparticles with an aim of producing desired structures for applications.

Interactome of millet-based food matrices: A review

Millets are recently being recognized as emerging food ingredients with multifaceted applications. Whole grain flours made from millets, exhibit diverse chemical compositions, starch digestibility and physicochemical properties. A food matrix can be viewed as a section of food microstructure, commonly coinciding with a physical spatial domain that interacts or imparts specific functionalities to a particular food constituent. The complex millet-based food matrices can help individuals to attain nutritional benefits due to the intricate and unique digestive properties of these foods. This review helps to fundamentally understand the binary and ternary interactions of millet-based foods. Nutritional bioavailability and bioaccessibility are also discussed based on additive, synergistic, masking, the antagonistic or neutralizing effect of different food matrix components on each other and the surrounding medium. The molecular basis of these interactions and their effect on important functional attributes like starch retrogradation, gelling, pasting, water, and oil holding capacity is also discussed.

Effect of a novel shell material-Starch-protein-fatty acid ternary nanoparticles on loading levels and in vitro release of curcumin

Preparation of ternary nanoparticles using high amylose complex, stearic acid, and soy protein isolate as shell materials and their encapsulation of curcumin were studied. The effect of curcumin in ternary nanostructures, loading capacity of the nanoparticles, its solubility and sustained release behavior in vitro are discussed. The encapsulation efficiency of the ternary nanoparticles was 87.14 ± 0.70%, and the loading rate was 16.81 μg/g. Qualitative analysis showed that curcumin addition increases the long-range and short-range ordered structure of ternary starch (TS) by changing its crystallinity. Fourier transform infrared spectroscopy showed that curcumin-TS is formed via hydrogen bonds and hydrophobic properties of the protein. An in vitro release test showed that TS particles can control the stable release of curcumin in simulated intestinal fluid. Our study provided a novel approach to high biomass encapsulation and sustained release of polyphenols.

Effect of protein-fatty acid interactions on the formation of starch-lipid-protein complexes

The effect of interactions between beta-lactoglobulin (βLG) and lauric acid (LA) on the formation of ternary maize starch-LA-protein complexes was investigated. Analysis of the secondary structure of βLG by FTIR and changes in fluorescence λmax and intensity indicated that βLG and LA interacted during heating and cooling in a Rapid Visco Analyser (RVA). Results from RVA, DSC and Raman spectroscopy analyses showed that increasing the concentration of βLG from 25 to 200 mg increased the amount of ternary starch-LA-βLG complexes formed. There was little difference in the amounts of the ternary complexes formed when the amount of βLG was 25-150 mg, but a greater amount of starch-LA-βLG complexes was formed when 200 mg of βLG was pre-mixed with LA. From this study, we concluded that prior interaction between βLG and LA had no significant effect on the formation of ternary starch-LA-βLG complexes.

Encapsulation and delivery of bioactive citrus pomace polyphenols: a review

Citrus pomace consists of the peel, pulp, and membrane tissues remaining after juice expression. Globally, around one million tons of citrus pomace are generated annually, which contains a variety of bioactive constituents that could be used as value-added functional ingredients in foods. However, the polyphenols in citrus pomace are not currently being utilized to their full potential, even though they can be used as nutraceuticals in functional foods and beverages. Citrus phenolics face significant roadblocks to their successful incorporation into these products. In particular, they have poor water solubility, chemical stability, and bioavailability. This review describes the diverse range of colloidal systems that have been developed to encapsulate and deliver citrus phenolics. Examples of the application of these systems for the encapsulation, protection, and delivery of polyphenols from citrus pomace are given. The use of colloidal delivery systems has been shown to improve the stability, dispersibility, and bioaccessibility of encapsulated polyphenols from citrus pomace. The selection of an appropriate delivery system determines the handling, storage, shelf life, encapsulation efficiency, dispersibility, and gastrointestinal fate of the citrus polyphenols. Furthermore, the purity, solubility, and chemical structure of the polyphenols are key factors in delivery system selection.

Toward a Better Understanding of Starch-Monoglyceride-Protein Interactions

The aim of the present study was to investigate the interactions between maize starch (MS), β-lactoglobulin (βLG), and monoglycerides (MG) containing different fatty acids in a model system. Results from the Rapid Visco Analyzer (RVA) showed that MS-MG_C14:0 and MS-MG_C16:0 systems presented a viscosity peak during the RVA cooling and/or holding stage, while MS-MG_C18:0, MS-MG_C18:1, and MS-MG_C18:2 systems did not show obvious changes in the pasting profile. Addition of βLG altered significantly the pasting profiles of MS-MG systems in different ways, with the most obvious change observed for the MS-MG_C18:0 system. Results from differential scanning calorimetry (DSC), Raman spectroscopy, and X-ray diffraction showed that the complexes in ternary systems were more ordered than those in binary systems. The thermal transition temperatures of complexes in binary and ternary systems were similar, although the enthalpy changes were greater for ternary than for binary systems. From the above results, we concluded that addition of βLG promoted the formation of MS-MG complexes rather than the involvement of formation of ternary MS-MG-βLG complexes.

Effects of Chain Length and Degree of Unsaturation of Fatty Acids on Structure and in Vitro Digestibility of Starch-Protein-Fatty Acid Complexes

The effects of chain length and degree of unsaturation of fatty acids (FAs) on structure and in vitro digestibility of starch-protein-FA complexes were investigated in model systems. Studies with the rapid visco analyzer (RVA) showed that the formation of ternary complex resulted in higher viscosities than those of binary complex during the cooling and holding stages. The results of differential scanning calorimetry (DSC), Raman, and X-ray diffraction (XRD) showed that the structural differences for ternary complexes were much less than those for binary complexes. Starch-protein-FA complexes presented lower in vitro enzymatic digestibility compared with starch-FAs complexes. We conclude that shorter chain and lower unsaturation FAs favor the formation of ternary complexes but decrease the thermal stability of these complexes. FAs had a smaller effect on the ordered structures of ternary complexes than on those of binary complexes and little effect on enzymatic digestibility of both binary and ternary complexes.

Insights into the Formation and Structures of Starch-Protein-Lipid Complexes

The aim of the present study was to characterize the multiscale structures of ternary complexes of a model system of starch, fatty acid (FA), and β-lactoglobulin (βLG) prepared using a Rapid Visco Analyzer (RVA). The addition of βLG to starch-lauric acid or starch-oleic acid RVA pastes resulted in the increased intensity or occurrence of a new viscosity peak during cooling when the RVA protocol was repeated. The viscosity peak was attributed to the formation of starch-βLG-FA complexes. Differential scanning calorimetry (DSC) results showed clearly that the starch-βLG-FAs complex was formed as gelatinized starch was cooled in the presence of βLG and FAs. The results of Raman, FTIR, and X-ray diffraction analyses showed that starch can interact with βLG and FAs to form a ternary V-type crystalline complex, which had a greater short-range molecular order and higher relative crystallinity compared with those of the binary starch-FA complex. The present study provided insights into the structure of a model starch-protein-fatty acid complex as an example of what might occur during food processing.

Filler functionality in edible solid foams

We review the functionality of particulate ingredients in edible brittle foams, such as expanded starchy snacks. In food science and industry there is not a complete awareness of the full functionality of these filler ingredients, which can be fibers, proteins, starch granules and whole grains. But, we show that much can be learned about that from the field of synthetic polymeric foams with (nano)fillers. For edible brittle foams the enhancement of mechanical strength by filler ingredients is less relevant compared to the additional functionalities such as 1) the promotion of bubble nucleation and 2) cell opening-which are much more relevant for the snack texture. The survey of particulate ingredients added to snack formulations shows that they cannot be viewed as inert fillers, because of their strong hygroscopic properties. Hence, these fillers will compete with starch for water, and that will modify the glass transition and boiling point, which are important factors for snack expansion. Filler properties can be modified via extrusion, but it is better if that processing step is decoupled from the subsequent processing steps as mixing and expansion. Several filler ingredients are also added because of their nutritional value, but can have adverse effect on snack expansion. These adverse effects can be reduced if the increase of nutritional value is decoupled from other filler functionality via compartmentalization using micropellets.

Self-assembled nanoparticle of common food constituents that carries a sparingly soluble small molecule

A previously reported nanoparticle formed through the self-assembly of common food constituents (amylose, protein, and fatty acids) was shown to have the capacity to carry a sparingly soluble small molecule (1-naphthol) in a dispersed system. Potentiometric titration showed that 1-naphthol locates in the lumen of the amylose helix of the nanoparticle. This finding was further supported by calorimetric measurements, showing higher enthalpies of dissociation and reassociation in the presence of 1-naphthol. Visually, the 1-naphthol-loaded nanoparticle appeared to be well-dispersed in aqueous solution. Molecular dynamics simulation showed that the self-assembly was favorable, and at 500 ns, the 1-naphthol molecule resided in the helix of the amylose lumen in proximity to the hydrophobic tail of the fatty acid. Thus, sparingly soluble small molecules, such as some nutraceuticals or drugs, could be incorporated and delivered by this soft nanoparticle carrier.

Free fatty acids electronically bridge the self-assembly of a three-component nanocomplex consisting of amylose, protein, and free fatty acids

The self-assembly of a ternary complex, which is formed through heating and cooling of a mixture of amylose (1.0 mg/mL), whey protein isolate (50 μg/mL), and free fatty acids (FFAs, 250 μg/mL) was investigated. High-performance size-exclusion chromatography-multi-angle laser light scattering (HPSEC-MALLS) analysis showed that the complex is a water-soluble supramolecule (Mw = 6-7 × 10(6)), with a radius of gyration of 20-100 nm, indicating a nanoscale complex. Experimental results using 1-monostearyl-rac-glycerol (MSG) or cetyl alcohol that is similar to FFA in structure (except the headgroup) indicate that FFAs are the bridge between thermodynamically incompatible amylose and protein molecules and their functional carboxyl group is essential to the formation of the complex. Additionally, the effects of pH and salt treatments suggest that electrostatic interactions between negatively charged carboxyl groups of FFAs and polyionic protein are the foundation for the self-assembly of the complex. The fact that FFA is one important component in the self-assembled complex with an estimated molar ratio of 6:1:192 (amylose/protein/FFA, ∼4-5% FFA) demonstrates that it might be used as a nanocarrier for the controlled release of lipophilic functional materials to maintain their stability, bioactivity, and more importantly water solubility.

Delivery of bioactive conjugated linoleic acid with self-assembled amylose-CLA complex

A delivery system for bioactive conjugated linoleic acid (CLA) through a self-assembled amylose-CLA complex was investigated in comparison with a beta-cyclodextrin (BCD)-CLA complex. Successful complexation between CLA and amylose or BCD was confirmed by differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectral analysis. The yield and complexing percentages were 71.9 and 1.4% for the amylose-CLA complex and 42.3 and 7.7% for the BCD-CLA complex, respectively. However, the amylose-CLA complex showed a better antioxidative protection effect on CLA than BCD-CLA complex, supporting a strong complexing interaction between CLA and amylose shown by thermogravimetric analysis. Compared to 15.9% of CLA released from the BCD-CLA complex under simulated small intestine conditions, 95.6% of CLA was released from the amylose-CLA complex. These results indicate that an amylose-lipid complex self-assembled in the natural way of food component interaction can be used to protect and deliver functional lipids or other bioactive components into the targeted small intestine for absorption.