Impact of plasma-activated water on the supramolecular structure and functionality of small and large starch granules.

Hydrothermal (HMT) and water agitation (WA) treatments using plasma-activated water (PAW) were employed as sustainable methods to modify the molecular and functional performance of small (rice) and large (potato) starch granules. HMT-PAW and WA-PAW treatments resulted in etched and damaged granular surfaces that rearranged the long and short-range crystallinity of the modified starches. Both treatments seemed to predominantly occur in the amorphous region of the rice starch and the crystalline regions of the potato starch, changing the crystallinity values from 22.9 and 14.8 % to 31.8 and 10.4 %, respectively. Thus, the level of the arrangement of chains reached after PAW treatment decreased the ability of rice starch granules to swell (16 to 9 %) and leach out starch molecules from the granules (4.5 to 1.3 %), decreasing the viscosity and pasting profiles as indicated by n and k values. Opposite behavior was observed in the modified potato starches since starch components leached out to a higher extent (1.7 to 5.4 %). The results showed that HMT and WA treatments using PAW are feasible eco-friendly methods for modifying starch granules without chemical reagents. These modified starches could be suitable as functional ingredients or biopolymeric matrices for the food and packaging industry.

Effect of retrograded starch with different amylose content on the rheological properties of stored yogurt.

Resistant starch (RS) promotes health benefits; however, when added to foods, it could change the rheological properties. The effect of adding different concentrations (2.5, 5, 7.5, and 10%) of retrograded corn starch with 27% (RNS) or 70% (RHS) amylose content on the properties of yogurt was evaluated through measurements of flow behavior and gel structure. Syneresis and resistant starch content were also assessed. Results were analyzed using multiple regression to describe the effect of starch concentration and storage time on the properties of yogurt added with RNS or RHS. Syneresis was reduced, RNS reinforced the structure increasing the water absorption capacity and the consistency index; meanwhile, RHS provided a yogurt containing up to 10 g of RS in 100 g of sample, allowing obtaining a functional dairy product. Creep-recovery test showed that adding RNS or RHS favored the matrix conformation, and the yogurt samples were able to recover. The final product behaved like a solid material with a firmer and more stable gel structure, resulting in a strengthened gel without weakening the yogurt structure, showing a characteristic like Greek-style or stirred yogurt depending on the type and concentration of retrograded starch. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05735-x.

Effect of adding high concentrations of retrograded starch with different amylose content on the physicochemical properties and sensory attributes of Greek-style yogurt.

It is well known that using retrograded starches confers many technological advantages, as well as health benefits when consumed in adequate doses; however, these properties are closely related to the type of starch and/or the treatment applied, therefore, it is of interest to add retrograded starch to popular products such as Greek yogurt. The aim of this work was to investigate the effect of adding two types of retrograded corn starch with different amylose content to a non-strained type of Greek-style yogurt. Retrograded starch from starch containing 27 % (RNS) or 70 % (RHS) amylose was added to yogurt at 0, 10, 12.5, or 15 g/100 g before storage at 4 °C for 14 d. The resistant starch (RS) content, pH, syneresis, flow behavior index, and consistency index, were measured every week. A sensory test was carried out in yogurt added with 12.5 g/100 g of retrograded starches to evaluate acceptance. Adding retrograded starch significantly reduced syneresis while increased the consistency, firmness, and resistant starch content of the yogurt. No significant differences in general acceptance were observed in samples added with RNS when compared to the control. Although a significant difference was observed after adding RHS, the acceptance of the product is still convenient. Adding a high concentration of retrograded starch could help to ensure doses enough for a prebiotic effect of RS with concentrations of 1.74 ± 0.37 to 2.32 ± 0.09 g/100 g and from 3.5 ± 0.08 to 4.21 ± 0.08 g/100 g when RNS or RHS is added respectively, while maintaining the quality characteristics of Greek-style yogurt during storage without compromising the acceptability.

Supramolecular structure and technofunctional properties of starch modified by high hydrostatic pressure (HHP): A review.

This review focuses on describing and discussing recent findings regarding the effects of high hydrostatic pressure (HHP) on the supramolecular structure and technofunctional properties of starch, as well as on analyzing the hypothesis to explain these changes. The non-thermal modification of starch through HHP involves complex supramolecular structural changes that depend on the botanical source, amylose content, and treatment intensity. Overall, the granular morphology, lamellar and crystalline structures, and double helices undergo different degrees of modification/disorganization during HHP, but these changes are distinguished from thermal modification by an improvement at the same gelatinization degree. The HHP-induced supramolecular modifications determine the properties of starch, including water solubility, swelling power, pasting, water and oil holding capacity, thermal properties, and in vitro digestibility.

Interactions of the molecular assembly of polysaccharide-protein systems as encapsulation materials. A review.

Studying the interactions of biopolymers like polysaccharides and proteins is quite important mainly due to the wide number of applications such as the stabilization and encapsulation of active compounds in complex systems. Complexation takes place when materials like proteins and polysaccharides are blended to promote the entrapment of active compounds. The interaction forces between the charged groups in the polymeric chains allow the miscibility of the components in the complex system. Understanding the interactions taking place between the polymers as well as between the wall material and the active compound is important when designing delivery systems. However, some features of the biopolymers like structure, functional groups, or electrical charge as well as extrinsic parameters like pH or ratios might affect the structure and the performance of the complex system when used in encapsulation applications. This work summarizes the recent progress of the polysaccharide/protein complexes for encapsulation and the influence of the pH on the structural modifications during the complexation process.

Dual modification of achira (Canna indica L) starch and the effect on its physicochemical properties for possible food applications.

The aim of this study was to evaluate the effect of acid hydrolysis and succination upon single and a combination of both of them as a dual modification on the morphological, structural, thermal, and pasting profile of the achira starch in order to expand its potential food applications. The surface of achira starch granules was eroded with acid hydrolysis, while the succination resulted in the formation of pores or cavities, having a slight impact on the crystallinity and the gelatinization enthalpy. Succinated starch presented the lowest transition temperatures (To = 60.29 °C, Tp = 65.03 °C and Te = 69.86 °C) compared to other starches in this study. The succination increased the final viscosity (3808 cp) when compared with the native starch (3114 cp), while acid hydrolysis resulted in a decreased value (735 cp). These are desirable properties for its possible use as an additive in bakery industry processes.

Rheological performance of film-forming solutions made from plasma-modified starches with different amylose/amylopectin content.

Normal and high amylose corn starches were modified using HMDSO plasma at different time treatments. Changes in functional properties of starch granule, film-forming solutions (FFS) and films were investigated. SEM analysis revealed HMDSO coating deposition on the granule surface, which limited the amylopectin leach out from the granules to the continuous matrix, affecting the rheological properties of the FFS. The amylopectin restriction resulted in a low reinforcement of the network decreasing the viscosity as indicated by n and k values. Also, a gel-like behavior (G' > G″) was observed when the amylose and time treatment increased, suggesting that the matrix becomes less elastic with softer entanglement. This behavior was confirmed by creep test and Burger model parameters. The plasma treatments allowed obtaining FFS with low viscosity, suitable for developing soft and hydrophobic films with low flexibility, as indicated by the decrease of the maximum stress, Hencky strain and permeance values.

Retrogradation of autoclaved corn starches: Effect of water content on the resistant starch formation and structure.

In this study, the resistant starch (RS) formation, crystallinity, and double helical order of autoclaved (120 °C) normal (ANS) and high amylose (AHS) corn starches retrograded at ~4-26% of water content were investigated. ANS and AHS retrograded at ~25-26% of water content were more crystalline (~35-40%) and formed by more close-packed double helices (R1000/1022 cm-1 = 1.145-1.290). The highest content of RS (38.8%) was found in AHS retrograded at 25.52% of water content meanwhile in ANS, the maximum content of RS was 6.6% at 21.60% of water content despite its structural order was increased with the increase of water content. The recrystallization of amylopectin interfered with the formation of homogeneous crystalline structures of amylose preventing the formation of retrograded RS in ANS, while in AHS, a relationship between structure and RS formation was observed, suggesting that the close-packed double helices and the proportion of homogeneous amylose crystallites increased the resistance to enzymatic digestion.

Films made from plasma-modified corn starch: Chemical, mechanical and barrier properties.

In this study, the chemical, mechanical and barrier properties of films made from plasma-modified corn starch (MSF) were evaluated as a function of the amylose content (30, 50 and 70 %). SEM analysis revealed the presence of remnant starch granules (RSG) in all films, which promoted the ordering of helices as suggested by the FTIR results. Moreover, XPS analysis was used to identify the oxidation mechanism in all MSF as the atomic proportion of hydroxyl, carbonyl and carboxyl groups changed. Also, the increase of C-C proportions suggested crosslinking in MSF70. TGA analysis indicated low interaction between starch and the plasticizer as the tensile strength and elongation at break diminished in MSF50 and MSF70 due to the low plasticizing effect of glycerol, the oxidation phenomena and the depolymerization of starch chains. However, the crosslinking of MSF70 showed characteristics of rigid films with good hydrophobic performance.

Double helical order and functional properties of acid-hydrolyzed maize starches with different amylose content.

Two maize starches (Normal and Hylon VII) were hydrolyzed using HCL for 15 days at room temperature. The water holding capacity -WHC and oil holding capacity- OHC were evaluated to describe the changes during the reorganization of hydrolyzed material. The structure was assessed using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). A hydrolysis degree of 20% was reached with a complete granular structure disruption. During acid hydrolysis, the rearrangement of decoupled double helices favored the order degree. The hydrolysis of the amorphous region decreased the enthalpy of gelatinization. This effect was more noticeable in the normal starch. The changes promoted during the hydrolysis favored the reorganization of the network resulting in high values in WHC and OHC for both starches. The acid-treated starches obtained could be used as fillers, employing these materials with induced crystalline regions.

HMDSO plasma treatment as alternative to modify structural properties of granular starch.

In the present study, the effect of plasma treatment on the structural properties of three granular corn starches (normal, Hylon V and Hylon VII) was investigated. Thermal (TGA/DSC), structural (XRD/FTIR) and chemical (XPS) properties were evaluated. Plasma treatment resulted in partial evaporation of water molecules changing the organization level of the double helices in the crystalline lamellae. Moreover, XRD results suggested a decrease of the long-range crystallinity and suggested changes in amylose chains after treatments. The crosslinking of modified amylose chains measured by XPS analysis resulted in variations in the gelatinization parameters as well as in its heterogeneous crystalline structure. The results indicate that the type and extent of changes in the structure of plasma-treated corn starch depends on the distribution of the water molecules inside the crystalline regions (helical water) and on the amylose content. In addition, the obtained results indicated that plasma treatment is a suitable method to modify starch without any incorporation of new elements from hexamethyldisiloxane (HMDSO), which only promotes stronger interactions between the starch main components.

Digestibility and Acceptability of Wheat Flour Cookies Partially Substituted with High Amylose Maize Starch.

Cookies are one of the most consumed bakery products and the formulation could be modified to consider them as a functional food. The high amylose maize starch (HAMS) is considered as resistant starch (RS) type 2. The objective of this work was to assess the starch fractions, texture, sensory properties and acceptability of wheat flour cookies added with HAMS at different percentages. Adding 15% of HAMS into the formulation increased the amount of RS from 2.3 to 12.8%. In sensory analysis, children and adults showed a good acceptability of cookies since the addition of HAMS did not result in significant changes in flavor or color. Cookies made with HAMS could be considered as functional foods since they had an acceptable texture and low caloric content.

Influence of gelatinization process and HMDSO plasma treatment on the chemical changes and water vapor permeability of corn starch films.

In this study, surface, chemical, physicochemical and barrier properties of films treated with hexamethyldisiloxane (HMDSO) cold plasma were investigated. Normal and high amylose starches were gelatinized at different level to obtain films with different amount of free amylopectin. The obtained films were subjected to HMDSO plasma treatment. XPS analysis indicated chemical changes including substitution and crosslinking of the starch molecule, as reflected by the CSi bond increasing and the C-OH bonds reduction on treated films. These changes modified the thermal transitions (Tm and ΔH). The highest amount of CSi bonds was more noticeable in the TF50 film, suggesting a better interaction between active species of plasma and the free amylopectin released into the continuous phase of the film. Moreover, active species of plasma increased the crystallinity in all films. These results suggested that a higher helical packaging, crosslinking and hydrophobic blocking groups (CSi) of starch molecules resulted in films with improved barrier performance against water molecules.

Hexamethyldisiloxane cold plasma treatment and amylose content determine the structural, barrier and mechanical properties of starch-based films.

In this study, the effect of amylose content and cold plasma treatment on starch films properties was investigated. Films from normal (30%) and high amylose (50 and 70%) starches were subjected to hexamethyldisiloxane (HMDSO) cold plasma treatment. Morphological, structural, mechanical and barrier properties of the films were evaluated. The amount of remnant starch granules (RSG) in the films depended on the amylose content and on the gelatinization extent of the starch. This behavior was corroborated on the films from starch with 50% amylose, where the loss of RSG resulted in poor barrier properties and high hydrophilicity. Moreover, HMDSO cold plasma treatment incorporated methyl groups improving the hydrophobic properties and favored the helix ordering of the starch components resulting in a limited water-film interaction. Furthermore, the simultaneous effect of HMDSO coating and the ordering of the structures reinforced the surface of the films, improving the mechanical properties.

Rheological properties of nanocomposite-forming solutions and film based on montmorillonite and corn starch with different amylose content.

Nanoparticles (montmorillonite, MMT) can enhance biopolymer-based film properties. The structure-property relationship between polymers and nanoparticles may be explained by the rheological tests of nanocomposite forming solutions (NFS). The aim of this work was to study the effect of MMT concentration and amylose content on the rheological properties of NFS based on corn starch and glycerol following two preparation methods, through steady shear and dynamic tests. The organization level of NFS was influenced by the addition order of the components. Decreasing in flow index behavior when increasing amylose content was attributed to interactions between the starch components. In all NFS, G' was higher than G″ indicating a gel-like behavior and suggesting that the MMT reinforced the starch matrix as observed by the increase in the storage modulus of films with MMT. Films obtained from method 2 have better mechanical properties probably due to the starch-MMT interactions.

Acetylation of banana (Musa paradisiaca L.) and corn (Zea mays L.) starches using a microwave heating procedure and iodine as catalyst: II. Rheological and structural studies.

The effect of iodine concentration on the acetylation of starches with low and moderate degree of substitution (DS<0.5) and its impact on the physicochemical feature and structural features was evaluated. The acetylated starches were prepared with 0.03 mol anhydroglucose unit, 0.12 mol of anhydride acetic, and 0.6, 0.9 or 1.4 mM of molecular iodine as catalyst in a sealed Teflon vessel using microwave heating (600 W/2 min). Pasting profile and rheological properties were obtained under steady flow; dynamic oscillatory test was used. Structural features were obtained by HPSEC-RI. In acetylated starches, DS and acetyl groups increased when the iodine concentration increased, corn starch showed higher values than banana starch. The viscosity of acetylated starches decreased relative to unmodified starches while, acetylated corn starch had lower value than acetylated banana starch. In the flow curves, a non-Newtonian pattern (shear-thinning) was shown in the pastes of native and modified starches. Storage modulus (G') and loss modulus (G") showed low dependence on frequency (G'αω(0.1); G"αω(0.2)) on frequency sweep test, which is characteristic of a viscoelastic gel. Debranched native banana and corn starches presented trimodal chain-length distribution. The pattern was maintained in the acetylated starches, but with different level of short and long chains. The structural differences in native and acetylated samples explain the rheological characteristics in both starches.

In vitro digestibility of banana starch cookies.

Banana starch was isolated and used for preparation of two types of cookies. Chemical composition and digestibility tests were carried out on banana starch and the food products, and these results were compared with corn starch. Ash, protein, and fat levels in banana starch were higher than in corn starch. The high ash amount in banana starch could be due to the potassium content present in this fruit. Proximal analysis was similar between products prepared with banana starch and those based on corn starch. The available starch content of the banana starch preparation was 60% (dmb). The cookies had lower available starch than the starches while banana starch had lower susceptibility to the in vitro alpha-amylolysis reaction. Banana starch and its products had higher resistant starch levels than those made with corn starch.

Thermal and viscoselastic properties of starch isolated from Mexican corn hybrids

El objetivo de este trabajo fue caracterizar las propiedades térmicas (temperatura de gelatinización y temperatura de fusión del almidón retrogradado) y reológicas (viscoelasticidad y viscosidad en unidades Bravender) del almidón aislado de diferentes maíces híbridos cultivados en México. La temperatura de gelatinización de los almidones fluctuó de 71,5 a 74,7 °C. La temperatura de fusión del almidón retrogradado fue menor a los 7 y 14 días de almacenamiento que la temperatura de gelatinización, mientras que la entalpía de fusión fue, en general, mayor sólo a los 14 días de almacenamiento. El perfil reológico para las pastas formadas durante las primeras dos etapas (calentamiento cocimiento) de una cinética de tres etapas de calentamiento/enfriamiento, correspondió al de geles viscoelásticos débiles, con el módulo elástico mayor que el módulo viscoso (G'>G''), mientras que en la tercera etapa (enfriamiento), las pastas se comportaron como geles mayormente elásticos (G'>> G''). El viscoamilograma de las pastas de almidón mostró viscosidades máximas alrededor de los 93 °C para mezclas al 5 por ciento (p/v) de sólidos y 87 °C para mezclas con 10 (p/v) por ciento de sólidos. El análisis estadístico mostró diferencias significativas entre los almidones con respecto a su composición química, así como en sus propiedades térmicas y reológicas. Los resultados sugieren que estos almidones podrían utilizarse en alimentos no procesados, por su alta tendencia a retrogradar y su comportamiento de geles viscoelásticos "débiles" durante el procesamiento.