Progress in starch modification in the last decade

Enzymatic synthesis of wet-resistant lignosulfonate-starch adhesives

This work describes a new method for improving the properties, mainly the wet-resistance, of starch-based adhesives using enzymatically polymerized lignosulfonates. A correlation of viscosity with molecular weight was found, allowing simple control of enzymatic polymerization of lignosulfonates. Incorporation of lignosulfonates polymerized from 29 kDa to > 4500 kDa using laccase led to a considerable increase in wet-resistance (from 15 to 20 min for the laminating glue and from 150 to 1200 min for the bag glue) while not affecting (for the laminating glue) or even improving the bonding time (from 80 to 60 s for the bag glue). Finally, the effect of active laccase in the final adhesive was investigated by enzymatic inactivation using NaN₃ before formulation of the glue, as well as by extra laccase addition. In conclusion, this study shows that enzymatically polymerized lignosulfonate is a robust strategy for improving wet resistance of starch-based adhesives.

Pressure moisture treatment and hydro-thermal treatment of starch

Starch is often subjected to denaturation treatment to improve its useful properties and eliminate its shortcomings. Various methods have been developed to produce modified starches with different properties and for a variety of uses. Because physically modified starch can be produced without chemical substances or biological agents, the modification method is very simple and inexpensive, and the resulting material can be used as clean label starch. Among these physical modification technologies, heat moisture treatment (HMT) is a universally valid technology, but little is known about pressure moisture treatment (PMT)-related technology. Physical modification of starch using PMT results in new functions and value-added characteristics required by industry, and PMT has the potential to produce starch with new functions. In this paper, PMT-related technologies for physically modified starch, the difference between PMT and the hydro-thermal treatment, and clean label starch manufacturing using HMT and PMT were investigated.

Synthesis of starch nanoparticles with controlled morphology and various adsorption rate for urea

Starch nanoparticles (SNPs) with different morphology and particle size can be prepared by modulating the reaction conditions over SNPs preparation. This study was to synthesize various SNPs by using ultrasound assisted nanoprecipitation method, and characterized by particle size analysis, SEM and XRD performing. SNPs were successfully produced via nanoprecipitation and the particle size were controlled in the range of 95 to 150 nm. Moreover, variously different morphologies were obtained when using corn, potato or Trichosanthes kirilowii pulp (TKP) starch to produce nanoparticles, including fiber, flake and film. Results shown film TKP SNPs demonstrated an improved urea adsorption rate to 135.60 mg/g with the highest q_m at 1.00 mg/mL. SNPs can be developed using ultrasound assisted nanoprecipitation method and the particle size together with surface morphology can be varied according to the source of starch and preparation method, while surface morphology is the key factor in altering adsorption performance.

Effect of atmospheric pressure non-thermal pin to plate plasma on the functional, rheological, thermal, and morphological properties of mango seed kernel starch

This study aimed to investigate the effect of atmospheric pressure non-thermal pin-to-plate plasma on the functional, rheological, thermal, and morphological properties of mango seed kernel starch. As cold plasma contains highly reactive species and free radicals, it is expected to cause noticeable modifications in the attributes of starch treated. The isolated mango seed kernel starch was subjected to the plasma treatment of input voltages 170 and 230 V for 15 and 30 min of exposure. Water adsorption, swelling, and solubility at lower temperatures. There has been a significant reduction (p < 0.05) in pH values of starch from 7.09 to 6.16 and also the desirable reduction in turbidity values by 42.60%. However, there has been no significant change in the oil and water binding behavior of the starch. The FTIR spectra of MSKS demonstrate the formation of amines which contributes to the better hydrophilic nature of the starch. The structural modification has been adequately confirmed by SEM images. The maximum voltage and time combination, lead to depolymerization of starch which is supported by NMR spectra thus affecting thermal and rheological properties. The application of cold plasma-modified MSKS in food would facilitate stable and smooth textural development.

Progress in Starch-Based Materials for Food Packaging Applications

The food packaging sector generates large volumes of plastic waste due to the high demand for packaged products with a short shelf-life. Biopolymers such as starch-based materials are a promising alternative to non-renewable resins, offering a sustainable and environmentally friendly food packaging alternative for single-use products. This article provides a chronology of the development of starch-based materials for food packaging. Particular emphasis is placed on the challenges faced in processing these materials using conventional processing techniques for thermoplastics and other emerging techniques such as electrospinning and 3D printing. The improvement of the performance of starch-based materials by blending with other biopolymers, use of micro- and nano-sized reinforcements, and chemical modification of starch is discussed. Finally, an overview of recent developments of these materials in smart food packaging is given.

Influence of Phosphorylation and Acetylation on Structural, Physicochemical and Functional Properties of Chestnut Starch

Chestnut is popular worldwide for its unique flavor, high eating quality and nutrition. Here, we evaluated the influence of phosphorylation and acetylation on the structural, physicochemical and functional properties of chestnut starch. Scanning electron micrographs showed the agglomeration of starch granules and the appearance of numerous dents on the starch granule surface under phosphorylation and acetylation. X-ray diffractograms confirmed that the modification treatments did not affect the C-type crystal pattern, but reduced the relative crystallinity of the chestnut starch, particularly phosphorylation. Moreover, modification improved the paste transparency of the starch. Differential scanning calorimeter analysis revealed that the gelatinization temperature and enthalpy of the starch decreased with the increasing substitution degree, particularly in phosphorylated starch. The Rapid Visco Analyser analysis demonstrated that phosphorylation could greatly improve the pasting properties of chestnut starch. In addition, phosphorylated and acetylated starch had a smaller amount of slowly digested starch and a larger amount of resistant starch relative to native chestnut starch. In conclusion, the functional and physicochemical properties of chestnut starch can be significantly improved through phosphorylation and acetylation, demonstrating its great application potential as a food additive.

Gamma radiation as a modifier of starch – Physicochemical perspective

Starch is one of the most common and abundantly found carbohydrates in cereals, roots, legumes, and some fruits. It is a tasteless, colorless, and odorless source of energy that is present in the amyloplasts of plants. Native starch comprises amylose, a linear α-glucan having α-1,4-linkage and amylopectin, a branched polysaccharide with both α-1,4-linkage and α-1,6-linkage. Due to the low solubility, high viscosity, and unstable pasting property of native starch, it has been restricted from its application in industries. Although native starch has been widely used in various industries, modification of the same by various chemical, enzymatic and physical methods have been carried out to alter its properties for better performance in several industrial aspects. Physical modification like gamma radiation is frequently used as it is rapid, penetrates deeper, less toxic, and cost-effective. Starch when irradiated with gamma rays is observed to produce free radicals, generate sugars owing to cleavage of amylopectin branches, and exhibit variation in enzymatic digestion, amylose content, morphology, crystallinity, thermal property, and chemical composition. These physicochemical properties of the starch due to gamma radiation are assessed using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and its application are discussed.

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Assessment and comparison of morphological features of native and gamma-irradiated starch.

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Investigation of crystallinity and structural type of crystalline domains through XRD.

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FTIR spectroscopy confirmed the changes in chemical composition of gamma-irradiated and native starch.

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DSC analysis revealed the changes in gelatinization temperature of gamma-irradiated and native starch.

Corn Starch: Quality and Quantity Improvement for Industrial Uses

Corn starch serves as food, feed, and a raw material for industrial use. Starch makes up most of the biomass of the corn hybrid and is the most important and main yield component in corn breeding programs. Starch is composed of two polymers, branched amylopectin and linear amylose, which normally constitute about 75% and 25% of the corn starch, respectively. Breeding for corn starch quality has become economically beneficial because of the development of niche markets for specialty grains. In addition, due to the increased demands of biofuel production, corn ethanol production is receiving more attention. Consequently, improving starch quantity has become one of the most important breeding objectives. This review will summarize the use of corn starch, and the genetics and breeding of grain quality and quantity for industrial applications.

Starch engineered with Moringa oleifera seeds protein crosslinked Fe3O4: A synthesis and flocculation studies

This study aimed to utilize cationic protein extracted from the Moringa oleifera seed in the fabrication of cationic starch crosslinked with magnetic nanoparticles (MagCS). Important synthesis parameters include starch to cationic protein volume ratio, magnetic nanoparticles mass fraction, reaction and crosslinking time, reaction and crosslinking temperature and crosslinker concentration. At optimum synthesis conditions, MagCS yield a 38.55% amide content, 2.46 degree of substitution, 1.1 mmol/g charge density and 78.6% crosslinking, which are much higher compared to other starch derivatives. A series of characterization analyses such as Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, elemental analysis and vibrating sample magnetometer concluded that MagCS was embedded with amide group, has high crystallinity structure, is thermally stable and shows a promising magnetic characteristic. Based on the synthesis parameters and characterization studies, the synthesis mechanism of MagCS was also postulated. The flocculation performance of MagCS was successfully assessed for the treatment of palm oil mill effluent. At optimum dosage, initial pH and settling time of 1.0 g/L, 9.0 and 15 min, the MagCS flocculant was able to remove 90.48, 83.95 and 58.19% of turbidity, color and chemical oxygen demand, respectively. This study provides an alternative eco-friendly materials in the wastewater treatment application.

Understanding Wheat Starch Metabolism in Properties, Environmental Stress Condition, and Molecular Approaches for Value-Added Utilization

Wheat starch is one of the most important components in wheat grain and is extensively used as the main source in bread, noodles, and cookies. The wheat endosperm is composed of about 70% starch, so differences in the quality and quantity of starch affect the flour processing characteristics. Investigations on starch composition, structure, morphology, molecular markers, and transformations are providing new and efficient techniques that can improve the quality of bread wheat. Additionally, wheat starch composition and quality are varied due to genetics and environmental factors. Starch is more sensitive to heat and drought stress compared to storage proteins. These stresses also have a great influence on the grain filling period and anthesis, and, consequently, a negative effect on starch synthesis. Sucrose metabolizing and starch synthesis enzymes are suppressed under heat and drought stress during the grain filling period. Therefore, it is important to illustrate starch and sucrose mechanisms during plant responses in the grain filling period. In recent years, most of these quality traits have been investigated through genetic modification studies. This is an attractive approach to improve functional properties in wheat starch. The new information collected from hybrid and transgenic plants is expected to help develop novel starch for understanding wheat starch biosynthesis and commercial use. Wheat transformation research using plant genetic engineering technology is the main purpose of continuously controlling and analyzing the properties of wheat starch. The aim of this paper is to review the structure, biosynthesis mechanism, quality, and response to heat and drought stress of wheat starch. Additionally, molecular markers and transformation studies are reviewed to elucidate starch quality in wheat.

Characterization of Cationic Modified Short Linear Glucan and Fabrication of Complex Nanoparticles with Low and High Methoxy Pectin

In this study, we chemically modified the short linear glucan (SLG) using the 3-chloro-2-hydroxypropyl trimethylammonium chloride to introduce a positive surface charge via cationization (CSLG). We then prepared CSLG-based binary nanocomplex particles through electrostatic interactions with low and high methoxyl pectin. The two new types of binary nanocomplex were comprehensively characterized. It was found that the nanocomplex particles showed a spherical shape with the particle size of <700 nm, smooth surface, homogeneous distribution, and negative surface charge. Fourier transform infrared spectroscopy (FTIR) revealed that the driving forces to form nanocomplex were primarily electrostatic interactions and hydrogen bonding. In addition, increasing the CSLG concentration in the nanocomplex significantly enhanced both thermal stability and digestive stability. By comparing the two complex nanoparticles, the HMP-CSLG has a larger particle size and better stability under the GI condition due to the high content of the methoxy group. Additionally, the HMP-CSLG nanoparticle has a higher encapsulation efficiency and slower release rate under simulated gastrointestinal fluid for tangeretin compared with the LMP-CSLG. These results provide new insights into designing the CSLG-based nanocomplex as a potential oral delivery system for nutraceuticals or active ingredients.

Effect of selected physical and chemical modifications on physicochemical, pasting, and morphological properties of underutilized starch from rice bean (Vigna umbellata)

Starch was extracted from the rice bean which is largely underutilized and modified by physical (i.e. heat moisture treatment and retrogradation) and chemical (i.e. esterification and acid alcohol modification) methods. Both, physical and chemical modifications significantly (p < 0.05) affected the physicochemical, pasting, particle size and morphological properties of rice bean starch. Both amylose content and swelling power reduced after physical and chemical modifications. Among modified starches, retrograded starch showed higher solubility (8.56%) at 90 °C. Retrogradation also resulted in higher values of water (251%) and oil absorption (106%) capacities in comparison to other modified starches. Physical modifications greatly influenced the pasting properties in comparison to chemical modifications. The particle size distribution followed the order: native starch (659.8 nm) > heat moisture treated (434.3 nm) > retrograded (355.4 nm) > esterified (218 nm) > acid alcohol treated starch (234.5 nm). The study revealed that the particle size of rice bean starch was reduced by both physical and chemical modifications. FE-Scanning electron microscopy was used to study the morphological characteristics of starches and it was observed that retrogradation had a pronounced effect on the starch granules morphology.

Analysis of Molar Substitution of Hydroxybutyl Group by Zeisel Reaction in Starch Ethers

A new etherified starch, δ-hydroxybutyl starch (δ-HBS), was prepared by utilising 4-chlorobutan-1-ol as the etherifying reagent. The method of Zeisel gas chromatography for the determination of the molar substitution was described. This technique offers a simple and rapid method for quantitative analysis with reproducible results. Meanwhile, the mechanism of the Zeisel reaction was also investigated.

Impacts of Hydrothermal Treatments on the Morphology, Structural Characteristics, and In Vitro Digestibility of Water Caltrop Starch

The influence of hydrothermal treatments on the structural properties and digestibility of water caltrop starch was investigated. Scanning electron microscopy (SEM) showed some small dents on the surface of starch granules for samples treated with heat moisture treatment (HMT), but not for samples treated with annealing (ANN) which generally showed smoother surfaces. The gelatinization temperature of starch was generally increased by hydrothermal treatments, accompanied by a trend of decreasing breakdown viscosity. These results implied the improvement of thermal and shearing stability, particularly for HMT in comparison to ANN. After being cooked, the native and ANN-modified water caltrop starch granules were essentially burst or destroyed. On the other hand, the margin of starch granules modified by HMT and dual hydrothermal treatments remained clear with some channels inside the starch granules. X-ray diffraction revealed that the crystalline pattern of water caltrop starch changed from the CA-type to the A-type and the relative crystallinity reduced with increasing moisture levels of HMT. Results of ANN-modified water caltrop starch were mostly similar to those of the native one. Moreover, water caltrop starch modified with HMT20 and dual modification contained a pronouncedly higher resistant starch content. These results suggested that HMT, ANN, and dual modification effectively modified the functional properties of water caltrop starch.

Effect of Esterification Conditions on the Physicochemical Properties of Phosphorylated Potato Starch

The aim of this study was to evaluate the effect of the temperature (15 or 45 °C) and the duration (15–120 min) of the modification process on the selected physicochemical, thermal, and rheological properties of phosphorylated potato starch. The modified starches contained 93.6–98.2 mg P/100 g (dry weight basis, d.w.b.). Phosphorylation caused color changes with a total color difference between the starches below 0.55, but these changes were less than those that were recognizable by the human eye. The thermal analysis showed two opposite processes appearing during the modification: the loosening of the structure (dominant among starches obtained at 15 °C) and the strengthening of the structure (dominant among starches obtained at 45 °C). The higher phosphorylation temperature reduced native starch recovery from 140% to 87–116% and increased the hysteresis loop area from −169 to 1040. All of the pastes made from the modified starches showed a weaker tendency for retrogradation (during 21 days of storage) than native starches. The results of the regression analysis conducted between the properties of the starch pastes obtained at 45 °C indicated that the modification time appeared to be a better indicator of the rate of modification progress than the phosphorus content. The PCA (principal component analysis) results made it possible to distinguish starch phosphates obtained at 15 °C from those obtained at 45 °C and those from natural starch.

Microbial starch debranching enzymes: Developments and applications

Starch debranching enzymes (SDBEs) hydrolyze the α-1,6 glycosidic bonds in polysaccharides such as starch, amylopectin, pullulan and glycogen. SDBEs are also important enzymes for the preparation of sugar syrup, resistant starch and cyclodextrin. As the synergistic catalysis of SDBEs and other starch-acting hydrolases can effectively improve the raw material utilization and production efficiency during starch processing steps such as saccharification and modification, they have attracted substantial research interest in the past decades. The substrate specificities of the two major members of SDBEs, pullulanases and isoamylases, are quite different. Pullulanases generally require at least two α-1,4 linked glucose units existing on both sugar chains linked by the α-1,6 bond, while isoamylases require at least three units of α-1,4 linked glucose. SDBEs mainly belong to glycoside hydrolase (GH) family 13 and 57. Except for GH57 type II pullulanse, GH13 pullulanases and isoamylases share plenty of similarities in sequence and structure of the core catalytic domains. However, the N-terminal domains, which might be one of the determinants contributing to the substrate binding of SDBEs, are distinct in different enzymes. In order to overcome the current defects of SDBEs in catalytic efficiency, thermostability and expression level, great efforts have been made to develop effective enzyme engineering and fermentation strategies. Herein, the diverse biochemical properties and distinct features in the sequence and structure of pullulanase and isoamylase from different sources are summarized. Up-to-date developments in the enzyme engineering, heterologous production and industrial applications of SDBEs is also reviewed. Finally, research perspective which could help understanding and broadening the applications of SDBEs are provided.

Study of the Performance of Particles Based on Modified Starches Containing Potassium Sorbate and Incorporated into Biodegradable Films: Physicochemical Characterization and Antimicrobial Action

Ultrasound technique was used to produce native and acetylated cassava starch particles containing potassium sorbate (KS). In order to obtain an active packaging, films with addition of native starch particles containing KS (NKSPF) or added with acetylated starch particles containing KS (AKSPF) were formulated. As control systems, films without KS (CF) or added with KS that was not retained in particles (KSF), were produced. The NKSPF and AKSPF microstructure was consistent with composite materials. Tensile test revealed that CF and KSF were ductile and extensible (stress at break (σb) 2.8–2.5 MPa and strain at break (εb) 284–206%), while NKSPF and AKSPF were more resistant films with higher Young’s Modulus (148–477 MPa) and σb (3.6–17 MPa) but lower εb (40–11%). Moreover, NKSPF and AKSPF developed lower Yellowness Index (6.6–6.5) but higher opacity (19–23%) and solubility in water (31–35%) than KSF (9, 10.8% and 9%, respectively). It was observed that KSF and NKSPF moderately reduced the Zygosaccharomyces bailii growth while AKSPF showed the highest yeast inhibition, three Log-cycles, compared to CF. Additionally, FTIR spectroscopy revealed intensified interactions between KS and modified starch. It was concluded that starch sonication and acetylation were useful modifications to produce particles carrier of KS that improved the physical and antimicrobial performance of active films.

Structural variations of rice starch affected by constant power microwave treatment

Although lots of work has reported the structural variations of starch in microwave treatment, most of them are detected in the environment with non-constant microwave power and inhomogeneous heating, and the results are always in poor repeatability. In this study, the equipment with constant microwave power (CPM) and homogeneous heating was designed. And the phase transition of multi-scale structure of rice starch (30% moisture content) caused by CPM treatments with two heating modes, namely rapid microwave heating (RWH) and slow microwave heating (SWH) were investigated systematically. SEM results showed that the surface of starch granules after CPM treatment were rough and broken, and the damage caused by RWH was more distinct than that by SWH. SAXS, XRD and ¹³C NMR results revealed that the CPM treatment decreased the degree of crystallinity and content of double helices of starch. Moreover, the influence of RWH on the variation of starch granules was greater than that of SWH, which can be attributed to the intensive friction and collision as well as the rapid evaporation of water in RWH treatment. Specifically, it exhibited greater destruction on the linkage of starch and the internal crystalline region in RWH treatment than SWH treatment, thereby resulting in more obvious damages on the lamellar and morphological structure of rice starch. In conclusion, CPM equipment has improved the problems of uneven heating and poor experimental repeatability. After CPM treated starch, the molecular structure of starch was destroyed, which provides a useful method to modify properties of starch.

Millet starch: A review

The demand for millets and their products is becoming popular globally due to their various health-promoting properties. The major constituent of the millet is its starch which contributes about 70% of total millet grain and decides the quality of millet-based food products. The application of starch for various purposes is dependent upon its physicochemical, structural, and functional properties. A native starch does not possess all the required properties for a specific use. However, product-specific properties can be achieved by modifying the structure of starches. Information deficit on millet starch has undermined its potential use in new food product design. The objective of this review is to examine the chemical composition, characterization, structural chemistry, digestibility, hydrolysis, and modification techniques of the millet starches. The review paper also discusses the various applications of native and modified starches in the food industry.

Pearl millet grain as an emerging source of starch: A review on its structure, physicochemical properties, functionalization, and industrial applications

Pearl millet (Pennisetum glaucum (L.) R.Br.) is a sustainable and underutilized starch source, constituting up to 70 % starch in its grain. Pearl millet could be used as a cheaper source of starch as compared to other cereals for developing functional foods. This review is mainly focused on isolation methods, and chemical composition of the pearl millet starch (PMS). Techno-functional characteristics such as; gelatinization, pasting properties, solubility, swelling power, and digestibility to infer wider application of the PMS critically highlighted in the review. Native starches have limited functionalitiesfor food applications due to the instability in developed pastes and gels. A number of modifications (physical, mechanical and enzymatic) have been developed to increase the functionality and to obtain desired characteristics of PMS thus improving its utilization in food applications. Further, the utilization of native as well as modified PMS is also discussed comprehensively. In addition, a number of recommendations to further improve its functionality and increase its application are also discussed.

A review on the physicochemical properties of starches modified by microwave alone and in combination with other methods

Native starches are unsuitable for most industrial applications. Therefore, they are modified to improve their application in the industry. Starch may be modified using enzymatic, genetic, chemical, and physical methods. Due to the demand for safe foods by consumers, researchers are focusing on the use of cheap, safe and environmentally friendly methods such as the use of physical means for starch modification. Microwave heating of starch is a promising physical method for starch modification due to its advantages such as homogeneous operation throughout the whole sample volume, shorter processing time, greater penetration depth and better product quality. More recently, the use of synergistic methods for starch modification is being encouraged because they confer better functionality on starch than single methods. This review summarizes the present knowledge on the structure and physicochemical properties of starches from different botanical origins modified using microwave heating alone and in combination with other starch modification methods.

Analysis of porous structure of potato starch granules by low-field NMR cryoporometry and AFM

Pore size distribution is a crucial structural element affecting the adsorption and diffusion of reagents and enzymes within starch granules. An accurate and credible method of determining the pore size distribution of starch granules especially for smooth ones is therefore required. In this work, low-field NMR cryoporometry (LF-NMRC) was applied to analyze the pore structure of potato starch (PS). The reliability of the LF-NMRC method is verified by comparing with the traditional method, i.e. the low temperature nitrogen adsorption (LT-NA). Both LF-NMRC and LT-NA could characterize the PS pore structure in mesoporous range. However, LF-NMRC has superiority over LT-NA in terms of the distinguishment and determination of pore size distribution approaching to the micropores, gives more accurate and reliable results than LT-NA does. Structural evidences from scanning electron microscope (SEM) and atomic force microscope (AFM) further indicated that the new proposed method is a non-destructive method that does not induce structural changes during sample preparation.

Modifying Effects of Physical Processes on Starch and Dietary Fiber Content of Foodstuffs

Carbohydrates are one of the most important nutrients in human consumption. The digestible part of carbohydrates has a significant role in maintaining the energy status of the body and the non-digestible parts like dietary fibers have specific nutritional functions. One of the key issues of food processing is how to influence the technological and nutritional properties of carbohydrates to meet modern dietary requirements more effectively, considering particularly the trends in the behavior of people and food-related health issues. Physical processing methods have several advantages compared to the chemical methods, where chemical reagents, such as acids or enzymes, are used for the modification of components. Furthermore, in most cases, these is no need to apply them supplementarily in the technology, only a moderate modification of current technology can result in significant changes in dietary properties. This review summarizes the novel results about the nutritional and technological effects of physical food processing influencing the starch and dietary fiber content of plant-derived foodstuffs.