Wheat starch swelling, gelatinization and pasting: Effects of enzymatic modification of wheat endogenous lipids

Rheological behavior and release dynamics of pregelatinized pink potato starch modified by stearic acid

The effects of stearic acid (5 %, 10 %, and 15 % w/w) and pregelatinized pink potato starch (20, 25, and 30 min) on complex formation, physicochemical properties, rheology, and release characteristics were investigated. Moisture content decreased from 14.26 % in pregelatinized starch to 13.25 %, 12.85 %, and 11.45 % in complexes with 5 %, 10 %, and 15 % stearic acid, respectively. Water-holding capacity dropped from 268.68 % to 128.26 %, 95.05 %, and 50.63 %, with increasing stearic acid concentrations. Swelling and solubility power also decreased, with swelling power reducing from 5.57 % to 3.45 % and solubility from 12.75 % to 10.34 %. Micromeritic evaluations showed improved flowability in starch-stearic acid complexes. X-ray diffraction revealed a V-type crystalline complex with characteristic peaks at 7°, 21°, 22°, and 24°, and additional peaks at 7° and 41°. FTIR spectra indicated complex formation with bands around 2917 and 1700 cm-1. FESEM imaging showed intact granules with irregular shapes and protruding amylose fragments. Rheological assessments indicated reduced viscosity and altered viscoelastic properties in the complexes. In-vitro release studies demonstrated controlled drug release, suggesting potential applications for targeted pharmaceutical delivery. This study emphasizes the functional modifications induced by stearic acid in pregelatinized starch, enhancing material properties for industrial and biomedical applications.

The important role of starch fine molecular structures in starch gelatinization property with addition of sugars/sugar alcohols

The relationship between the fine structure of starch and its gelatinization properties is not well studied, particularly in relation to the influence of sugar or sugar alcohol. In this study, seven starches with distinct molecular structures were investigated to determine how different sugars and sugar alcohols affect their gelatinization properties. The inclusion of sugars and sugar alcohols resulted in a significant elevation of starch gelatinization temperatures (∼ 8 °C), especially with sucrose, isomaltose and isomalt. Nevertheless, the influence of these sugars/ sugar alcohols on the gelatinization temperature range and enthalpy change varied depending on the particular starch varieties. According to the correlation analysis, sugars and sugar alcohols mainly exert their impact on the starch gelatinization temperature range and enthalpy change by possibly interacting with amylose chains possessing a degree of polymerization ranging from 100 to 1000 (p < 0.05) and inhibiting the amylose leaching during gelatinization. These findings help a better understanding of the complex relationship between starch fine structure and gelatinization properties under the influence of sugars and sugar alcohols.

Reduction of starch granule surface lipids alters the physicochemical properties of crosslinked maize starch

Normal and waxy maize starches with and without removal of starch granule surface lipids (SGSLs) were crosslinked by POCl3 (0.01 %, 0.1 % and 1 %). Crosslinked starches showed lower swelling power and solubility, but higher pasting viscosity, pseudoplasticity, thixotropy, storage modulus and loss modulus. Crosslinking increased the double helical structure but decreased the crystallinity for waxy maize starch. The phosphorus content of crosslinked waxy maize starches after SGSLs removal increased, indicating SGSLs removal promoted crosslinking. SGSLs removal increased G' and G" for crosslinked waxy maize starches. SGSLs removal increased SP and solubility and decreased pasting and rheological parameters of starches. With increased POCl3 dosage, the effect of SGSLs removal on starch properties was gradually suppressed by crosslinking. Waxy and normal maize starches showed significantly different changes with crosslinking and SGSLs removal, and the presence of amylose seemed to impede the effect of crosslinking and SGSLs removal. The removal of SGSLs could extend the application of crosslinked starch in frozen foods, drinks, and canned foods as thickener and stabilizer, due to its better hydrophilicity and viscous liquid-like rheological properties. The study will assist carbohydrate chemists and food processors in developing new food products.

Effect of Medium Chain Triglycerides on the Digestion and Quality Characteristics of Tea Polyphenols-Fortified Cooked Rice

Nowadays, medium chain triglycerides (MCT) with special health benefits have been increasingly applied for fortifying food products. Therefore, the present work aimed to investigate the effects of MCT on traditional tea polyphenols-fortified cooked rice (TP-FCR). It was visualized by DSC, CLSM, XRD, FT-IR, and Raman spectroscopy. The higher content of starch-MCT complexes with an increase in the relative crystallinity and the generation of short-range ordered structures contributed to a more ordered and compact molecular arrangement, which can hinder the action of digestive enzymes on starch. SEM demonstrated that MCT transformed the microstructure of TP-FCR into a denser and firmer character, making it an essential component hindering the accessibility of digestive enzymes to starch granules and slowing the release of tea polyphenols in TP-FCR to attenuate starch digestion. Consequently, the addition of MCT reduced the polyphenol-regulated starch digestibility from 74.28% in cooked white rice to 64.43% in TP-FCR, and further down to 50.82%. Besides, MCT also reduced the adhesiveness and improved the whiteness of TP-FCR. The findings suggested that MCT incorporation could be a potential strategy in cooked rice production to achieve high sensory quality and low glycemic cooked rice.

Removing starch granule-associated surface lipids affects structure of heat-moisture treated hull-less barley starch

The effects of starch granule-associated surface lipids removal on hull-less barley starch structure formed by heat-moisture treatment were investigated. Removing surface lipids made the peak at 2θ of 13^° disappear and resulted in higher lamellar peak intensity after harsh treatment and a lower reduction in mass fractal dimension (from 2.49 to 2.43) and radius of gyration (from 24.3 to 24.0) when temperature increased from 100 to 120 °C at 20 % moisture. Treatment at 25 % moisture and 120 °C decreased relative crystallinity (from 15.73 % to 7.43 %) and Gaussian peak area (from 646.7 to 137.7) of native starch, and decreased relative crystallinity (from 14.24 % to 12.56 %) and Gaussian peak area (from 604.1 to 539.6) for starch without surface lipids. Different trends of change in lamellar thickness, linear crystallinity, peak temperatures, and enthalpy of gelatinization were observed among modified starches with increasing temperature and/or moisture content. These results demonstrate that removing surface lipids changes structure of heat-moisture treated starch.

Removal of starch granule-associated surface and channel lipids alters the properties of sodium trimetaphosphate crosslinked maize starch

Starch granule-associated surface and channel lipids (SGALs) were effectively removed from waxy maize starch (WMS) and normal maize starch (NMS), then the starches were crosslinked by different levels of sodium trimetaphosphate (STMP) (0.25 %, 0.5 %, 1 % and 2 %). The effective removal of SGALs and successful crosslinking, were evidenced by the disappearance of surface-fluorescence and channel-fluorescence of Pro-Q Diamond-stained granules, and the increased phosphorus content respectively. STMP crosslinking increased peak and final viscosity for WMS and NMS. Crosslinking at high STMP levels (0.5 %, 1 % and 2 %) transformed the starch pastes from thixotropic to anti-thixotropic. STMP crosslinking significantly decreased the tan δ values of maize starches, enhancing the elastic structure of the gel. Crosslinked maize starches without SGALs had lower breakdown than crosslinked starches at same STMP level, indicating higher tightened crosslinked starch granules after SGALs removal. Removal of SGALs increased the anti-thixotropy of crosslinked starches, facilitating the reorientation of crosslinked amylopectin/amylose molecules during shearing. Removal of SGALs increased the tan δ values from frequency sweep of WMS and NMS during STMP crosslinking, indicating the presence of surface-lipids and channel-lipids could enhance the elastic gel network structure of crosslinked maize starch.

Establishment of a quality evaluation system of sweet potato starch using multivariate statistics

Background

The quality of starch greatly affects the quality of processed products. There are many indexes for quality evaluation of starch. Currently, amylose content is considered the chief index in the quality evaluation of sweet potato starch, which is entirely based on tradition (experience) method. The existing evaluation standards lack quality evaluation standards for sweet potato starch.

Purpose

To screen reasonable evaluation indexes of sweet potato starch, and establish a scientific and systematic evaluation system of sweet potato starch.

Methods

Twenty-two components and quality indexes of sweet potato starch were measured. The evaluation indexes of sweet potato starch were screened based on a statistical description, correlation analysis, and principal component analysis (PCA), and a quality evaluation model of sweet potato starch for brewing was established based on analytic hierarchy process. The calculated values of the model were verified by linear fitting with standardized sensory evaluation values.

Results

The coefficient of variation of total starch content (%), amylose content (%), amylopectin content (%), L* value, ΔE, water absorption capacity (g/g), and pasting temperature was less than 6%, while the coefficient of variation of other indexes was larger. In addition, there were different degrees of correlation among the indexes. PCA was used to identify interrelated variables, and the first six principal components together account for 82.26% of the total variability. Then, seven core indexes — setback (cp), rate of regression (%), ratio of amylose to amylopectin (%), gel strength (kgf/cm2), a* value, ash content (%), and solubility (%) — were selected from the six principal components according to the load value of the rotation matrix. These seven core indexes replaced the original 22 indexes to simplify the evaluation of sweet potato starch. The quality evaluation model of sweet potato starch was Y = 0.034X2 + 0.321X6 + 0.141X8 + 0.08X17 + 0.023X19 + 0.08X21 + 0.321X22.

Conclusion

The comprehensive evaluation system of sweet potato starch can accurately predict the quality of sweet potato starch. The development of such a system is of great significance to the post-harvest processing of high-starch sweet potato and the breeding of high-quality and high-starch sweet potato varieties.

Relationship of Starch Pasting Properties and Dough Rheology, and the Role of Starch in Determining Quality of Short Biscuit

Starch plays an important role in food industry. In this study, three wheat cultivars with different protein contents were used to investigate the different ratios of starch addition on starch pasting properties, starch thermal performance, dough rheology, biscuit quality, and their relationships. Results showed that with the increase in starch content, gluten, protein and glutenin macropolymer (GMP), lactic acid solvent retention capacity (SRC), sucrose SRC, and onset temperature (To) decreased, while most pasting parameters and gelatinization enthalpy (ΔH) increased. Viscosity parameters were significantly negatively correlated with dough stability time, farinograph quality number (FQN), and sucrose SRC. Biscuit quality was improved by starch addition, indicated by lower thickness and hardness, higher diameter, spread ratio, and sensory score. Viscosity parameters were positively correlated to diameter, spread ratio, and sensory score of biscuit, while negatively correlated to hardness and thickness of biscuit. Image analysis showed that the crumbs of biscuit were improved as shown by bigger pores in the bottom side. The results provide useful information for the clarification of the role of starch in determining biscuit quality and the inter-relationships of flour, dough, and biscuit.

Fat replacers in baked products: their impact on rheological properties and final product quality

Many baked products, except for bread, (i.e., cakes, cookies, laminated pastries, and so on) generally contain high levels of fat in their formulas and they require different bakery fats that impart product-specific quality characteristics through their functionalities. Even though, fat is crucial for baked product quality, strategies have been developed to replace fat in their formulas as high fat intake is associated with chronic diseases such as obesity, diabetes, and cardiovascular heart diseases. Besides, the solid bakery fats contain trans- and saturated fats, and their consumption has been shown to increase total and low-density lipoprotein cholesterol levels and to constitute a risk factor for cardiovascular diseases when consumed at elevated levels. Therefore, the aim of this review was to provide a detailed summary of the functionality of lipids/fats (endogenous lipids, surfactants, shortening) in different baked products, the rheological behavior of bakery fats and their contribution to baked product quality, the impact of different types of fat replacers (carbohydrate-, protein-, lipid-based) on dough/batter rheology, and on the quality characteristics of the resulting reduced-fat baked products.

Effect of Endogenous Lipids and Proteins on the Antioxidant, in vitro Starch Digestibility, and Pasting Properties of Sorghum Flour

This study evaluated the effect of endogenous lipids and proteins on the antioxidants, starch digestibility, and pasting properties of sorghum (Sorghum bicolor) flour (SF). Endogenous lipids and/or proteins were removed from different portions of SF to obtain defatted (DF), deproteinized (DP), and defatted and deproteinized (DF-DP) flours. Bioactive constituents (total phenolics, tannins, flavonoids, saponins, and anthocyanins), antioxidant activities [2,2-Azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) radical cation (ABTS*+) and 2, 2-Diphenyl-2-picrylhydrazyl radical (DPPH*) scavenging activities, reducing power, and Fe2+ chelating capacity], starch, amylose, starch hydrolysis index (HI), estimated glycemic index (eGI), and pasting properties of treated and control (untreated) flours were determined. The control flour (SF) had significantly higher (p < 0.05) levels of all the bioactive constituents and antioxidant activity tested than the DF, DP, and DF-DP flours, while the DF-DP flour had the least levels of bioactive constituents and antioxidant activity. In contrast, the starch, amylose, HI, and eGI were consistently in the order of DF-DP > DF > DP > control flour (p < 0.05). The control flour had the highest (p < 0.05) peak viscosity, and the least peak time and pasting temperature, while the DF flour had the highest final viscosity. Therefore, endogenous lipids and proteins contribute to the antioxidant, starch digestibility, and pasting properties of sorghum flour.

Investigation of pesticide residue removal effect of gelatinized starch using surface-enhanced Raman scattering mapping

This study investigated the effectiveness of gelatinized starch (GS) in the removal of surface and internalized pesticide residues from basil leaves. Surface activity of GS was confirmed by surface tension and fluorescence study. Surface-enhanced Raman scattering (SERS) mapping was applied for in situ and real-time tracking of pesticides over time. Results showed that gelatinized starch has better and safer pesticide removing effect compared to commercial surfactants. Simulation study showed that starch fragment can adjust its three-dimensional conformation according to the size of the guest with ~ four repeating α-1,4-d-glucopyranose residues interacting efficiently with pesticides. However, washing by small molecular weight surfactants will lead to a "secondary contamination" due to its amphilphilic nature and small molecular size, which can escort pesticide deeper into the leaf. Due to the wide availability, easy fabrication, efficient rinsing effect and bio-safety nature, GS should be highly recommended in family practice.

Rheological and technological characterization of red rice modified starch and jaboticaba peel powder mixtures

Properties of modified starch and its interaction with functional raw materials are of great interest to the food industry. Thus, this study aimed to evaluate the rheological and technological characterization of starches modified by the action of the enzymes α-amylase and amyloglucosidase and their mixtures with jaboticaba peel powder. The parameters of firmness, gumminess, and final viscosity of starches paste increased, and the tendency to setback was reduced with the addition of jaboticaba peel powder. Starches and mixtures presented shear-thinning behavior. The addition of jaboticaba peel powder to starches increased water, oil, and milk absorption capacity, while syneresis remained stable over the storage period. The addition of jaboticaba peel powder had a positive effect on native and modified starches' rheological and technological properties, qualifying it as an alternative for developing new functional food products.

A Review on the Design and Hydration Properties of Natural Polymer-Based Hydrogels

Hydrogels are hydrophilic 3D networks that are able to ingest large amounts of water or biological fluids, and are potential candidates for biosensors, drug delivery vectors, energy harvester devices, and carriers or matrices for cells in tissue engineering. Natural polymers, e.g., cellulose, chitosan and starch, have excellent properties that afford fabrication of advanced hydrogel materials for biomedical applications: biodegradability, biocompatibility, non-toxicity, hydrophilicity, thermal and chemical stability, and the high capacity for swelling induced by facile synthetic modification, among other physicochemical properties. Hydrogels require variable time to reach an equilibrium swelling due to the variable diffusion rates of water sorption, capillary action, and other modalities. In this study, the nature, transport kinetics, and the role of water in the formation and structural stability of various types of hydrogels comprised of natural polymers are reviewed. Since water is an integral part of hydrogels that constitute a substantive portion of its composition, there is a need to obtain an improved understanding of the role of hydration in the structure, degree of swelling and the mechanical stability of such biomaterial hydrogels. The capacity of the polymer chains to swell in an aqueous solvent can be expressed by the rubber elasticity theory and other thermodynamic contributions; whereas the rate of water diffusion can be driven either by concentration gradient or chemical potential. An overview of fabrication strategies for various types of hydrogels is presented as well as their responsiveness to external stimuli, along with their potential utility in diverse and novel applications. This review aims to shed light on the role of hydration to the structure and function of hydrogels. In turn, this review will further contribute to the development of advanced materials, such as "injectable hydrogels" and super-adsorbents for applications in the field of environmental science and biomedicine.

Effects of thermal properties and behavior of wheat starch and gluten on their interaction: A review

Starch and gluten, the most important macromolecules in wheat flour, vary in thermal properties. The thermal behavior of starch, gluten and their complexes during the manufacture and quality control of flour products need to be accurately understood. However, the high complexity of starch-gluten systems impedes the accurate description of their interactions. When heated within varying temperature ranges and when water molecules are involved, the behaviors of amylose and amylopectin change, and the properties of the starch are modified. Moreover, important indicators of starch granules such as gelatinization temperature, peak viscosity, and so on, which are encapsulated by the gluten matrix, are altered. Meanwhile, the high-temperature environment induces the opening of the intrachain disulfide bonds of gliadin, leading to an increase in the probability of interchain disulfide bond formation in the gluten network system. These behaviors are notable and may provide insights into this complex interaction. In this review, the relationship between the thermal behavior of wheat starch and gluten and the quality of flour products is analyzed. Several methods used to investigate the thermal characteristics of wheat and its flour products are summarized, and some thermal interaction models of starch and gluten are proposed.

Effects of native starch and modified starches on the textural, rheological and microstructural characteristics of soybean protein gel

The effects of native starch (NS), acetylated starch (AS), and acetylated distarch phosphate (ADSP) on the gel properties of soybean protein thermal gel were investigated using texture analysis, low-field nuclear magnetic resonance (LF-NMR) spectroscopy, dynamic rheometry and scanning electron microscopy. The results of the textural profile analysis showed that 10% ADSP increased the hardness and chewiness of the mixed gel, while NS and AS led to decreases in the textural properties. The results of the LF-NMR analysis indicated that the AS improved the water-holding capacity of the mixed gel due to the transformation of weakly bound water to strongly bound water. During heating and cooling, the rheological profiles of the elastic (G') and viscous modulus (G″) of all the samples exhibited a two-stage pattern of decrease and then increase, and the final values of G' and G″ reached maxima when the ADSP content was 10%. The scanning electron microscopy images showed that the ADSP granules dispersed in the gel network. The integrity of the starch granules was crucial for regulating the properties of the soybean protein gel. These results provided information about the further design and preparation of soybean protein foods containing modified starch.

Effects of starch addition on the activity and specificity of food-grade lipases

Lipases are surface-active enzymes, acting on their substrates at the polar/nonpolar interface in emulsions. This study was aimed to test whether their activity, specificity, and the rates of formation/degradation of the various hydrolysis intermediates (i.e., mono- and diglycerides of interest as surface-active agents) could be modulated by adhesion of the triglyceride substrates as a thin layer on the surface of solids. These hypotheses were tested by using an array of food-grade lipases used in bakery, testing various types of starch as the "solid" phase. Starch-dependent increase in the hydrolysis rate was tested by pH-stat techniques on pure triglycerides and on food-grade oils in diluted emulsions. Starch-related improvements in the rate of fatty acids release were most evident at temperatures above 40 °C, and when using maize starch instead of wheat starch. Starch-dependent changes in the nature of the hydrolysis products were tested by chromatographic profiling of ethyl ether extracts from aqueous slurries containing up to 33% fat and 33% starch. Accumulation of mono- and diglycerides as hydrolysis intermediates was found to be modulated by the type of oil being used, by the reaction conditions, as well as by the enzyme nature and amount.

Characterization and Prebiotic Effect of the Resistant Starch from Purple Sweet Potato

Purple sweet potato starch is a potential resource for resistant starch production. The effects of heat-moisture treatment (HMT) and enzyme debranching combined heat-moisture treatment (EHMT) on the morphological, crystallinity and thermal properties of PSP starches were investigated. The results indicated that, after HMT or EHMT treatments, native starch granules with smooth surface was destroyed to form a more compact, irregular and sheet-like structure. The crystalline pattern was transformed from C-type to B-type with decreasing relative crystallinity. Due to stronger crystallites formed in modified starches, the swelling power and solubility of HMT and EHMT starch were decreased, while the transition temperatures and gelatinization enthalpy were significantly increased. In addition, HMT and EHMT exhibited greater effects on the proliferation of bifidobacteria compared with either glucose or high amylose maize starch.