Physical and chemical modification of starches: A review

Improving physicochemical and nutritional attributes of rice starch through green modification techniques

Rice, has long been an inseparable part of the human diet all over the world. As one of the most rapidly growing crops, rice has played a key role in securing the food chain of low-income food-deficit countries. Starch is the main component in rice granules which other than its nutritional essence, plays a key role in defining the physicochemical attributes of rice-based products. However, rice starch suffers from weak techno-functional characteristics (e.g., retrogradability of pastes, opacity of gels, and low shear/temperature resistibility. Green modification techniques (i.e. Non-thermal methods, Novel thermal (e.g., microwave, and ohmic heating) and enzymatic approaches) were shown to be potent tools in modifying rice starch characteristics without the exertion of unfavorable chemical reagents. This study corroborated the potential of green techniques for rice starch modification and provided deep insight for their further application instead of unsafe chemical methods.

Sequential effects of autoclaved heat treatment and electron beam irradiation on acorn starch: Multiscale structural differences and related mechanisms

In this study, the differences in the modification effects and related mechanisms of different times (20 and 40 min) of autoclaved heat (AH) treatment and different doses (2 and 4 kGy) of electron beam irradiation (EBI) in different sequences of effects on acorn starch were investigated. The results showed that both AH and EBI reduced the amylose content (22.70 to 19.59%) and enthalpy (10.28 to 1.84%) of starch but increased the resistant starch content (53.69 to 64.11%). AH treatment made the crystalline regions of the residual starch granules denser, which was resistant to the action of amylase enzymes. EBI degraded the long chain of starch, which increased the solubility. Notably, EBI pretreatment improves the reactive sites by inducing depolymerization and disorder in starch internal structure, thus increasing the modification extent of AH-modified starch, forming starch with lower viscosity, better hydration, and digestibility resistance, therefore being used as an ingredient for functional foods.

Exploring the remarkable effects of microwave treatment on starch modification: From structural evolution to changed physicochemical and digestive properties

As one of the crucial components of the food system, starch can be hydrolyzed into glucose after gastrointestinal digestion, so regulating its digestive properties is vital for maintaining health. Microwaves can promote the rearrangement of intramolecular structure of starch, thus improving its physicochemical properties, enhancing its slowly digestible features, and expanding its scope of application. This review zooms in describing recent research results concerning the effects of microwave treatment on the multi-scale structure and physicochemical properties of starch and summarizing the patterns of these changes. Furthermore, the changes in starch structure, resistant starch content, and glycemic index after digestion are pointed out to gain an insight into the enhancement of starch slowly digestible properties by microwave treatment. The resistance of starch to enzymatic digestion may largely hinge on the specific structures formed during microwave treatment. The multi-level structural evolutions of starch during digestion endow it with the power to resist digestion and lower the glycemic index. The properties of starch dictate its application, and these properties are highly associated with its structure. Consequently, understanding the structural changes of microwave-modified starch helps to prepare modified starch with diversified varieties and functional composites.

High-amylose starch-based gel as green adhesive for plywood: Adhesive property, water-resistance, and flame-retardancy

The escalating demand for environmentally sustainable and cost-effective adhesives in the wood processing and manufacturing sector has prompted exploration into innovative solutions. This study introduces a novel gel adhesive composed of chemically unmodified high-amylose starch (G70, with 68 % amylose content) with a minimal proportion of urea-formaldehyde (UF) (UF/starch = 1:10, w/w). This G70/UF gel demonstrates remarkable adhesive capabilities for wooden boards under both dry conditions (with a shear stress of 4.13 ± 0.12 MPa) and wet conditions (with a shear strength of 0.93 ± 0.07 MPa after 2 h of water soaking). The study unveils that the elevated amylose content in the starch, coupled with a meticulously controlled isothermal process during bonding, is crucial for these enhancements. Specifically, the robust cohesion of amylose chains expedites phase separation between starch and UF, while the isothermal process facilitates the migration and enrichment of UF molecules at the gel-board and gel-air interfaces. Lacking these mechanisms, conventional amylopectin-rich starch/UF gels (27 % amylose content) show minimal improvement. Moreover, the G70/UF gel showcases exceptional fire retardancy. In all, the G70/UF gel presents a promising alternative for plywood production, reducing reliance on unhealthy UF resin while offering satisfactory bonding resistance in diverse conditions and superior flame retardancy.

Mild alkali treatment alters structure and properties of maize starch: The potential role of alkali in starch chemical modification

Normal and waxy maize starches were treated with mild alkali treatment (pH 8.5, 9.9, 11.3) in two temperature-time combinations (25 °C for 1 h and 50 °C for 18 h) to investigate the effect on starch structure and properties. Mild alkali treatment partly removed the starch granule-associated proteins and lipids of normal (from 0.31 % to 0.24 % and from 0.77 % to 0.55 %, respectively) and waxy maize starches (from 0.22 % to 0.18 % and from 0.24 % to 0.15 %, respectively). Gelatinization enthalpy of waxy maize starch increased with alkali treatment from 16.20 J·g-1 to 21.95 J·g-1, indicating that amylopectin (AP) rearrangement and AP-AP double helices formation might occur. But amylose could inhibit these effects by restricting mobility of amylopectin, and no such changes occurred for normal maize starch. Alkali treatment decreased gelatinization temperature and increased peak and final viscosity. Alkali treatment decreased trough viscosity and increased setback of normal maize starch. The hydrothermal treatment promoted the effect of alkali, attributed to the more rapid molecular motion at higher temperature. Normal and waxy starches showed different changes after alkali treatment, indicating that amylose played an important role in controlling the effect of alkali and hydrothermal treatment, primarily as an obstructer of amylopectin rearrangement in mild alkali treatment.

Natural polymer starch-based materials for flexible electronic sensor development: A review of recent progress

In response to the burgeoning interest in the development of highly conformable and resilient flexible electronic sensors capable of transducing diverse physical stimuli, this review investigates the pivotal role of natural polymers, specifically those derived from starch, in crafting sustainable and biocompatible sensing materials. Expounding on cutting-edge research, the exploration delves into innovative strategies employed to leverage the distinctive attributes of starch in conjunction with other polymers for the fabrication of advanced sensors. The comprehensive discussion encompasses a spectrum of starch-based materials, spanning all-starch-based gels to starch-based soft composites, meticulously scrutinizing their applications in constructing resistive, capacitive, piezoelectric, and triboelectric sensors. These intricately designed sensors exhibit proficiency in detecting an array of stimuli, including strain, temperature, humidity, liquids, and enzymes, thereby playing a pivotal role in the continuous and non-invasive monitoring of human body motions, physiological signals, and environmental conditions. The review highlights the intricate interplay between material properties, sensor design, and sensing performance, emphasizing the unique advantages conferred by starch-based materials, such as self-adhesiveness, self-healability, and re-processibility facilitated by dynamic bonding. In conclusion, the paper outlines current challenges and future research opportunities in this evolving field, offering valuable insights for prospective investigations.

Effect of microwave alone and microwave-assisted modification on the physicochemical properties of starch and its application in food

Native starch has poor stability and usually requires modification to expand its industrial application range. Commonly used methods are physical, chemical, enzymatic and compound modification. Microwave radiation, as a kind of physical method, is promising due to its uniform energy radiation, greenness, safety, non-toxicity. It can meet the demand of consumers for safe food. Microwave-assisted modification with other methods can directly or indirectly affect the structure of starch granules to obtain modified starch with high degree of substitution and low viscosity, and the modification efficiency is greatly improved. This paper reviews the effect of microwave radiation on the physicochemical properties of starch, such as granule morphology, crystallization characteristics, and gelatinization characteristics, as well as the application of microwave radiation in starch modification and starch food processing. It provides theoretical references and suggestions for the research of microwave heating modified starch and the deep processing of starchy foods.

A Comprehensive Review on Starch-Based Hydrogels: From Tradition to Innovation, Opportunities, and Drawbacks

Natural hydrogels based on renewable and inexpensive sources, such as starch, represent an interesting group of biopolymeric materials with a growing range of applications in the biomedical, cosmeceutical, and food sectors. Starch-based hydrogels have traditionally been produced using different processes based on chemical or physical methods. However, the long processing times, high energy consumption, and safety issues related to the synthesis of these materials, mostly causing severe environmental damage, have been identified as the main limitations for their further exploitation. Therefore, the main scientific challenge for research groups is the development of reliable and sustainable processing methods to reduce the environmental footprint, as well as investigating new low-cost sources of starches and individuating appropriate formulations to produce stable hydrogel-based products. In the last decade, the possibility of physically modifying natural polysaccharides, such as starches, using green or sustainable processing methods has mostly been based on nonthermal technologies including high-pressure processing (HPP). It has been demonstrated that the latter exerts an important role in improving the physicochemical and techno-functional properties of starches. However, as for surveys in the literature, research activities have been devoted to understanding the effects of physical pre-treatments via high-pressure processing (HPP) on starch structural modifications, more so than elucidating its role and capacity for the rapid formation of stable and highly structured starch-based hydrogels with promising functionality and stability, utilizing more sustainable and eco-friendly processing conditions. Therefore, the present review addresses the recent advancements in knowledge on the production of sustainable starch-based hydrogels utilizing HPP as an innovative and clean-label preparation method. Additionally, this manuscript has the ambition to give an updated overview of starch-based hydrogels considering the different types of structures available, and the recent applications are proposed as well to critically analyze the main perspectives and technological challenges for the future exploitation of these novel structures.

Effects of adding proteins from different sources during heat-moisture treatment on corn starch structure, physicochemical and in vitro digestibility

Proteins impact starch digestion, but the specific mechanism under heat-moisture treatment remains unclear. This study examined how proteins from various sources-white kidney bean, soybean, casein, whey-altered corn starch's structure, physicochemical properties, and digestibility during heat-moisture treatment (HMT). HMT and protein addition could significantly reduce starch's digestibility. The kidney bean protein-starch complex under HMT had the highest resistant starch at 19.74 %. Most proteins effectively inhibit α-amylase, with kidney bean being the most significantly (IC50 = 1.712 ± 0.085 mg/mL). HMT makes starch obtain a more rigid structure, limits its swelling ability, and reduces paste viscosity and amylose leaching. At the same time, proteins also improve starch's short-range order, acting as a physical barrier to digestion. Rheological and low-field NMR analyses revealed that protein enhanced the complexes' shear stability and water-binding capacity. These findings enrich the understanding of how proteins from different sources affect starch digestion under HMT, aiding the creation of nutritious, hypoglycemic foods.

Starch-derived carbon quantum dots: Unveiling structural insights and photocatalytic potential as a bio-sourced metal-free semiconductor

The optical appeal and sustainability of carbon quantum dots (CQDs) have led to these nanoparticles swiftly gaining attention and emerging as a new, multifunctional class of nanomaterials. This work centers on the hydrothermal preparation of CQDs utilizing starch, an abundant and renewable biopolymer, as the precursor. Extensive characterization via spectroscopy and microscopy techniques revealed that the starch-derived CQDs exhibit a spherical nanoscale morphology averaging a ∼ 4 nm diameter, demonstrating a red-orange photoluminescence emission. Diffuse reflectance spectroscopic analysis verified their semiconductor behavior, with an estimated direct band gap of 4.1 eV comparable to conventional semiconductors. The prepared CQDs demonstrated considerable promise as metal-free, semiconductor photocatalysts for degrading aqueous dye pollutants under UV irradiation. High photodegradation efficiencies of 45.11 %, 62.94 %, and 91.21 % were achieved for Acid Blue 21, Reactive Blue 94, and Reactive TB 133 dyes, respectively. Systematic investigations of critical process parameters like pH, CQDs dosage, dye concentration, and contact time provided vital insights into the photocatalytic mechanism. The bio-sourced CQD nanomaterials offer a sustainable pathway for effective environmental remediation.

Investigating the influence of CaCl2 induced surface gelatinization of red adzuki bean starch on its citric acid esterification modification: Structure-property related mechanism

This study prepared starch with different degrees of gelatinization (10 % and 30 %) by CaCl2, and further combined with citric acid at different concentrations (10 %, 20 %, and 30 %) for esterification. The results indicated that CaCl2 induced surface gelatinization and the esterification promoted its fragmentation. This synergistic modification induced depolymerization of starch chains and a decrease in molecular weight, although starch's Maltese cross, growth rings, and crystal type remained unchanged. Moreover, the synergistic modification induces a short-range ordered structure loss and the enthalpy decrease of starch, which induce starch pasting properties decrease and solubility increase. Furthermore, the introduction of ester groups by esterification increases the resistant starch content by limiting the binding sites for digestive enzymes. In conclusion, surface gelatinization can increase active reaction sites by disrupting the starch shell structure, and serves as a potential pretreatment to enhance the deep application of esterified starch in food and pharmaceutical fields.

Recent advances in starch-based coatings for the postharvest preservation of fruits and vegetables

Efficient and low-cost postharvest preservation of fruits and vegetables has always been one of the urgent problems to be solved in the food field. Due to the wide sources, good environmental and human safety, and high biodegradability, starch-based coating preservation method has great application prospects in the postharvest preservation of fruits and vegetables. However, starch materials also have the disadvantages of poor mechanical properties and easy water absorption performance, which makes it difficult to fully meet the requirements in practical production. Therefore, starch is often used in combination with other components to form composite materials. This paper began with an introduction to the preservation principles of edible starch-based coatings, including inherent properties and extra functional properties. Besides, the preservation principles of edible coatings and the recent advances in the field of fruit and vegetable preservation were also comprehensively reviewed, focusing on the preparation and application of starch-based coatings. The information will contribute to the further development of starch-based coatings to improve the postharvest preservation effect of fruits and vegetables.

Starch-based particles as stabilizers for Pickering emulsions: modification, characteristics, stabilization, and applications

The potential utilization of starch as a particle-based emulsifier in the preparation of Pickering emulsions is gaining interest within the food industry. Starch is an affordable and abundant functional ingredient, which makes it an excellent candidate for the stabilization of Pickering emulsions. This review article focuses on the formation, stabilization, and properties of Pickering emulsions formulated using starch-based particles and their derivatives. First, methods of isolating and modifying starch-based particles are highlighted. The key parameters governing the properties of starch-stabilized Pickering emulsions are then discussed, including the concentration, size, morphology, charge, and wettability of the starch-based particles, as well as the type and size of the oil droplets. The physicochemical mechanisms underlying the ability of starch-based particles to form and stabilize Pickering emulsions are also discussed. Starch-based Pickering emulsions tend to be more resistant to coalescence than conventional emulsions, which is useful for some food applications. Potential applications of starch-stabilized Pickering emulsions are reviewed, as well as recent studies on their gastrointestinal fate. The information provided may stimulate the utilization of starch-based Pickering emulsions in food and other industries.

Effect of electrostatic repulsion on barrier properties and thermal performance of gelatin films by carboxymethyl starch, and application in food cooking

Carboxymethyl starch (CST) was introduced to improve gelatin films and its practical application as edible high-performance films for food packaging and cooking was also investigated. The gelatin films modified by carboxymethyl starch exhibited the transparent appearance, tensile strength, barrier properties (oxygen, water vapor and UV light), and thermal performance (TGA, thermal shrinkage and heat-sealing strength). Resulting from the effect of electrostatic interaction modes on the properties of films, electrostatic repulsion could surpass electrostatic attraction in improving the tensile strength, oxygen barrier property and thermal stability of the films probably due to extensive physical entanglement without aggregation. Analysis of FTIR, zeta potential, interfacial dilatational rheology, shear rheological properties, XRD, Raman, SEM and AFM suggested that hydrogen bonding and electrostatic repulsion contributed to the excellent performance. The packaged food could also be cooked with the prepared film for porridge; and the film slightly influenced the shear rheological properties of porridge and imposed little effect on the odors (Electronic-Nose) of porridge. Hence, the gelatin films modified by carboxymethyl starch could potentially work as the edible inner packaging or the edible quantitative packaging for food, offer convenience for consumers, reduce the packaging waste and avoid an extra burden on environment.

Application and functional properties of millet starch: Wet milling extraction process and different modification approaches

In the past decade, the demand and interest of consumers have expanded for using plant-based novel starch sources in different food and non-food processing. Therefore, millet-based value-added functional foods are acquired spare attention due to their excellent nutritional, medicinal, and therapeutic properties. Millet is mainly composed of starch (amylose and amylopectin), which is primary component of the millet grain and defines the quality of millet-based food products. Millet contains approximately 70 % starch of the total grain, which can be used as a, ingredient, thickening agent, binding agent, and stabilizer commercially due to its functional attributes. The physical, chemical, and enzymatic methods are used to extract starch from millet and other cereals. Numerous ways, such as non-thermal physical processes, including ultrasonication, HPP (High pressure processing) high-pressure, PEF (Pulsed electric field), and irradiation are used for modification of millet starch and improve functional properties compared to native starch. In the present review, different databases such as Scopus, Google Scholar, Research Gate, Science Direct, Web of Science, and PubMed were used to collect research articles, review articles, book chapters, reports, etc., for detailed study about millet starch, their extraction (wet milling process) and modification methods such as physical, chemical, biological. The impact of different modification approaches on the techno-functional properties of millet starch and their applications in different sectors have also been reviewed. The data and information created and aggregated in this study will give users the necessary knowledge to further utilize millet starch for value addition and new product development.

Effect of ultrasonic frequency on the structural and functional properties of pea protein isolation

BACKGROUND

Pea protein, as a by-product of peas (Pisum sativum L.), is rich in a variety of essential amino acids that can meet the body's protein needs and is a valuable source of protein. Since the function of pea protein is closely related to its structure, pea protein has been subjected to different modifications in recent years to improve its application in food and to develop new products.

RESULTS

The effects of sonication frequency (primary and secondary time) on pea protein isolate's (PPI's) structural and functional properties were investigated. Sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that different sonication frequencies at the same power (600 W) treatment had no effect on PPI's molecular weight. Fourier-transform infrared spectroscopy revealed that treatment at different sonication frequencies caused secondary structural changes in PPI. The particle size distribution, foaming, stability, surface hydrophobicity, emulsification, and oxidation resistance of PPI were improved after primary and secondary sonication, but secondary sonication was not more effective than primary sonication for an extended period of time.

CONCLUSION

Overall, ultrasound is able to improve the structural and functional properties of pea proteins within a suitable range. It provides a theoretical basis for elucidating the modification of the structure and function of plant proteins by ultrasound and lays the foundation for the development of plant proteins in food applications as well as development. © 2023 Society of Chemical Industry.

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.

Jicama (Pachyrhizus spp.) a nonconventional starch: A review on isolation, composition, structure, properties, modifications and its application

Starch attracts food industries due to their availability in nature, cheapness, biodegradability and possibilities of endless applications. The starch properties and their modification affect food quality. Compared to other cereals, tuber and root starches, more systematic information is needed on the jicama starches (JS). This review article summarizes the isolation, composition, morphology, rheological, thermal and digestibility properties of JS. The modifications and its current and potential applications are also discussed. The chemical composition and structure of JS are different from other starches, influencing its properties. JS has been modified by physical and chemical methods to improve the properties of starch. However, there are very few studies on the modification of JS as compared with other commercial starch although it has been used in food formulation as a stabilizer and to improve the texture of food products. It is also applied as an edible coating to preserve the quality of food products and use as a raw material for making edible and bioplastic packaging. However, large-scale utilization of JS is unexplored compared to commercial starches. Therefore, this review would provide useful information and suggestions for more research on Jicama starch and its industrial applications.

Effect of polysaccharide addition on food physical properties: A review

The texture, flavor, performance and nutrition of foods are affected by their physical properties during processing, cooking, storage, and shelf life. In addition to chemical, physical, and enzymatic modification methods, polysaccharide addition is also considered a safe, effective, and convenient food modification strategy. However, thus far, literature review on the effects of polysaccharides on the physical properties of foods is few. Therefore, the present work reviews the effects of polysaccharides on water retention capacity, rheological property, suspension ability, viscoelasticity, emulsifying property, gelling property, stability, and starch regeneration and digestion. Furthermore, the existing problems and future recommendations during food physical property modification by polysaccharides are presented. This work aims to provide some theoretical references for future research, development, and application of polysaccharides on food physical property modification.

Heat-moisture treatment to modify structure and functionality and reduce digestibility of wrinkled and round pea starches

Heat-moisture treatment (HMT) was employed to modify wrinkled pea (74.2 % and 76.5 % amylose) and round pea starches (35.9 % and 34.8 % amylose) at 35.0 % moisture, 110 or 130 °C, and 6 h. HMT increased the gelatinization temperatures and decreased the gelatinization enthalpy changes, reduced the pasting viscosities and gel hardness, and enhanced the enzymatic resistance of the pea starches in comparison with the native counterparts, with greater extents of changes observed for HMT at 130 °C overall. Although HMT decreased the relative crystallinity and elevated the proportion of amorphous conformation, the remaining double-helical crystallites in the modified samples showed improved thermal stability as revealed by differential scanning calorimetry (DSC). More importantly, the HMT-modified pea starches required a higher heating temperature of 120 °C, rather than 95 °C, in Rapid Visco Analyser to provide greater pasting viscosities and develop firmer gels, suggesting that the modified samples had stronger molecular entanglement than the native counterparts. Such molecular entanglement could also reduce enzymatic digestion of HMT-modified starches after boiling in water. With more diverse functional profiles and increased resistant starch (RS) contents (particularly for the HMT-modified wrinkled pea starches having 22.7-29.9 % RS), the HMT-modified pea starches could be promising new ingredients for food applications.

Preparation and characterization of chemically modified tapioca starch-ionic liquid antibacterial films

The plasticizing and antibacterial effects of ionic liquids (ILs) in the preparation of tapioca starch-IL films were studied for the first time. 1-Ethyl-3-methylimidazolium acetate ([Emim][OAc]) caused complete disruption of starch crystallites during thermal compression, while some crystallites remained after the plasticization of starch with choline acetate ([Ch][OAc]). Compared to native tapioca starch (NTS), the plasticization of acetylated tapioca starch (ATS) and cross-linked tapioca (CTS) was slightly promoted and inhibited, respectively. Starch-[Emim][OAc] films exhibited higher hydrophobicity and mechanical properties but lower antibacterial activity than starch-[Ch][OAc] films. CTS-[Ch][OAc] films presented higher mechanical strength and antibacterial activity than NTS-[Ch][OAc] and ATS-[Ch][OAc] films. From this study, we conclude that ILs can be used in the preparation of antibacterial starch films to play the roles of plasticization and antibacterial activity. The antibacterial activity of starch films depends on types of ILs and their interactions with starch during film preparation.

Structural and property changes of starch derivatives under microwave field: A review

Native starches are commonly modified for desired properties because of their limited applications. Among various modifications, microwave irradiation has been gaining strong interests and becoming a focal area to transform starch during the last few years. Such interests reside in microwave irradiation's high heating rates, lesser extent of loss in nutritional qualities, and so on when compared with other approaches. This review summaries the effects of microwave field on the structural (e.g. morphology characteristic, lamellae structure, crystallinity, and molecular structure) and physicochemical properties (e.g. pasting properties and gelatinization) of naturally existing starch derivatives. Different microwave-assisted chemical derivatizations can directly or indirectly affect starch structure from the macroscopic to the microscopic level, thereby resulting in various functionalities. Moreover, conventional starch modification processes can be optimized by applying microwave irradiation to obtain modified starch with high degree of substitution and low viscosity. The future research will help to better understand the structural changes of microwave-assisted starch chemical derivatization and thereby creating a wide range of functionalities.

Insight into the improvement in pasting and gel properties of waxy corn starch by critical melting treatments

To improve the pasting and gel properties of waxy corn starch (WCS), the native starch was modified by critical melting (CM) at the onset temperature (TO), peak temperature (TP), and conclusion temperature (TC) (labeled CMO, CMP, and CMC respectively). CM treatments significantly enhanced the thermal stability of the WCS, as indicated by the increase in the peak gelatinization temperature, pasting temperature, and peak time. In addition, after CMP treatment, the storage modulus, hardness, gumminess, springiness, and chewiness of starch gels significantly increased by 43.29 %, 31.14 %, 23.36 %, 8.26 %, and 61.43 %, respectively, and the syneresis rate significantly decreased by 19.69 % (p < 0.05). These results indicated that CMP treatments significantly improved the gelling ability and freeze-thaw stability of the WCS. These results are ascribed to the partial disruption and enhanced rearrangement of the starch crystalline structure. CMP treatment induced the crystalline structure of starch to be partially disrupted and a hard structure was formed on the surface of starch granules. The hard structure in CMP-treated starch supplied more attachment points for crystalline structure rearrangement during gelatinization. Therefore, the above results indicated that CMP treatments can be used to modify starch to improve the pasting and gel properties of starch-based food products.

Modifications of native lotus (Nelumbo nucifera G.) rhizome starch and its overall characterization: A review

Lotus (Nelumbo nucifera G.) rhizomes are an under-utilized and sustainable starch source that constitutes up to 20 % starch. The review mainly focused on the extraction methods of starch, the chemical composition of LRS, and techno-functional characteristics such as swelling power, solubility, in vitro digestibility, pasting property, and gelatinization is highlighted in LRS review. Lotus rhizome starch (LRS) is also used as a water retention agent, thickening, gelling, stabilizing, and filling in food and non-food applications. Native starch has limited functional characteristics in food applications so by modifying the starch, functional characteristics are enhanced. Single and dual treatment processes are available to enhance microstructural properties, resistant starch, techno-functional, morphological, and, film-forming properties. Compared with other starch sources, there is a lack of systematic information on the LRS. Many industries are interested in developing food products based on starch such as nanoparticles, hydrogels, edible films, and many others. Additionally, there are several recommendations to improve the applications in the food industry. Finally, we provide an outlook on the future possibility of LRS.

A comprehensive review on starch: Structure, modification, and applications in slow/controlled-release fertilizers in agriculture

This comprehensive review thoroughly examines starch's structure, modifications, and applications in slow/controlled-release fertilizers (SRFs) for agricultural purposes. The review begins by exploring starch's unique structure and properties, providing insights into its molecular arrangement and physicochemical characteristics. Various methods of modifying starch, including physical, chemical, and enzymatic techniques, are discussed, highlighting their ability to impart desirable properties such as controlled release and improved stability. The review then focuses on the applications of starch in the development of SRFs. It emphasizes the role of starch-based hydrogels as effective nutrient carriers, enabling their sustained release to plants over extended periods. Additionally, incorporating starch-based hydrogel nano-composites are explored, highlighting their potential in optimizing nutrient release profiles and promoting plant growth. Furthermore, the review highlights the benefits of starch-based fertilizers in enhancing plant growth and crop yield while minimizing nutrient losses. It presents case studies and field trials demonstrating starch-based formulations' efficacy in promoting sustainable agricultural practices. Overall, this review consolidates current knowledge on starch, its modifications, and its applications in SRFs, providing valuable insights into the potential of starch-based formulations to improve nutrient management, boost crop productivity, and support sustainable agriculture.

Enzymes Immobilized into Starch- and Gelatin-Based Hydrogels: Properties and Application in Inhibition Assay

The present work is a review of the research on using hydrogels based on natural biodegradable polymers, starch, and gelatin for enzyme immobilization. This review addresses the main properties of starch and gelatin that make them promising materials in biotechnology for producing enzyme preparations stable during use and storage and insensitive to chemical and physical impacts. The authors summarize their achievements in developing the preparations of enzymes immobilized in starch and gelatin gels and assess their activity, stability, and sensitivity for use as biorecognition elements of enzyme inhibition-based biosensors.

Insights into the structural characteristics and in vitro starch digestibility on parboiled rice as affected by ultrasound treatment in soaking process

This study investigated ultrasound treatment as a protective parboiling technology for producing low GI rice. Indica and Japonica rice with different amylose contents were subjected to different ultrasound times (15 min, 30 min, and 60 min) and amplitudes (30, 60, and 100%) under soaking conditions for parboiling applications. Starch granules merged and lost their shape when ultrasound treatment time and amplitudes were increased up to 15 min and 30%, respectively. It increased the crystallinity, gelatinization temperatures and decreased pasting viscosity, promoting more resistant starch. The predicted glycemic index (GI) was reduced from 62.9 and 57.6 to 51.3 and 47.1 for Japonica and Indica, respectively. These results suggested that ultrasound soaking is a promising physical method to produce parboiled rice with a lower GI by promoting the formation of amylose chains and decreasing enzyme penetration efficiency.

Cationic starch: A functionalized polysaccharide based polymer for advancement of drug delivery and health care system - A review

Research and development in health care industry is in persistence progression. To make it more patient-friendly or to get maximum benefits from it, special attention to different advanced drug delivery system (ADDS) is employed that delivers the drug at the target site and will be able to sustain/control release of drugs. ADDS should be non-toxic, biodegradable, biocompatible along with desirable showing physicochemical and functional properties. These drug delivery systems can be totally based on polymers, either with natural or synthetic polymers. The molecular weight of polymer can be tuned and different groups of polymers can be modified or substituted with other functional groups. Degree of substitution is also tailored. Cationic starch in recent years is exploited in drug delivery, tissue engineering and biomedicine. Due to their abundant availability, low cost, easy chemical modification, low toxicity, biodegradability and biocompatibility, extensive research is now being carried out. Our present discussion will shed light on the usage of cationic starch in health care system.

Effect of ultrasound-microwave and microwave-ultrasound treatment on physicochemical properties of corn starch

Natural starch is an agricultural sourced biopolymer being low cost, biodegradable, high efficiently, renewable and easy available. Despite these advantages, phisochemical properties of native starch are limited for most industrial applications and must be modified. Ultrasound and microwave treatment have been widely applied separately for starch modification. Ultrasound treatment, with high efficiency and low cost, and microwave treatment, which produces homogeneous and high quality products, are short proceesing time technologies that can be used together to change the structure and properties of starches obtained from various plants. In this study the effects of ultrasound and microwave combined treatment on the physicochemical properties of natural corn starch were investigated. Corn starch was irritated using different combination of ultrasound-microwave and microwave-ultrasound treatment; using 90, 180, 360 and 600 W microwave power during 1, 2, 3 min, and using ultrasound at 35 °C constant temperature for 20, 30, 40 min. The structural changes of modified corn starches were determined by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses. Nowadays, many physical methods are used for starch modification, but limited studies were on ultrasound-microwave and microwave-ultrasound combined treatment method. As a result of this study, it was observed that ultrasound and microwave combination is an efficient, fast and environmentally friendly method for natural corn starch modification.

Influence of pre- or post-electron beam irradiation on heat-moisture treated maize starch for multiscale structure, physicochemical properties and digestibility

Electron beam irradiation (EBI) as a green technological method for starch modification can generate starch-based materials with new functions. This study modified maize starch by heat-moisture treatment (HMT) for 1 h and 3 h, and EBI with various intensities (5 kGy and 10 kGy), and their effects of treatment sequence on the multiscale structure, physicochemical properties and in vitro digestibility were investigated. EBI or HMT alone did not change the granule morphology and crystalline type, but reduced the crystallinity and molecular weight and increased the resistant starch content. HMT alone had no significant effect on the solubility of starch, while EBI led to a considerable increase in the solubility of maize starch. The combined treatment of EBI and HMT aggravated apparent viscosity reduction, and the HMT starch pretreated with EBI had a smaller molecular weight and lower viscosity. In contrast, post-EBI samples had higher solubility and RS content. Primarily, it has excellent potential for producing low-viscosity and high-solubility starch foods.

Effect of Ball-Milling on Starch Crystalline Structure, Gelatinization Temperature, and Rheological Properties: Towards Enhanced Utilization in Thermosensitive Systems

Starch's crystalline structure and gelatinization temperature might facilitate or hinder its use. Ball milling has frequently been mentioned in the literature as a method for reducing starch size and as a more environmentally friendly way to change starch, such as by increasing surface area and reactivity, which has an impact on other starch properties. In this study, starch samples were milled for varying durations (1, 5, 10, 20, and 30 h) and at different starch-to-ball mass ratios (1:6 and 1:20). Microscopy and XRD revealed that prolonged milling resulted in effective fragmentation and a decrease in crystallinity of the starch granules. Increasing milling times resulted in an increase in amylose content. Rheology and thermal studies revealed that gelatinization temperatures dropped with milling duration and that viscosity and thixotropy were directly influenced. The samples milled for 10, 20, and 30 h at a ratio of 1:20 were the most fragmented and upon drying formed a transparent film at ambient temperature, because of the lower gelatinization temperature. Starch ball milling could lead to the use of this material in thermosensitive systems.

Modification of Starches and Flours by Acetylation and Its Dual Modifications: A Review of Impact on Physicochemical Properties and Their Applications

Various modification treatments have been carried out to improve the physicochemical and functional properties of various types of starch and flour. Modification by acetylation has been widely used to improve the quality and stability of starch. This review describes the effects of acetylation modification and its dual modifications on the physicochemical properties of starch/flour and their applications. Acetylation can increase swelling power, swelling volume, water/oil absorption capacity, and retrogradation stability. The dual modification of acetylation with cross-linking or hydrothermal treatment can improve the thermal stability of starch/flour. However, the results of the modifications may vary depending on the type of starch, reagents, and processing methods. Acetylated starch can be used as an encapsulant for nanoparticles, biofilms, adhesives, fat replacers, and other products with better paste stability and clarity. A comparison of various characteristics of acetylated starches and their dual modifications is expected to be a reference for developing and applying acetylated starches/flours in various fields and products.

Starch Modification with Molecular Transformation, Physicochemical Characteristics, and Industrial Usability: A State-of-the-Art Review

Starch is a readily available and abundant source of biological raw materials and is widely used in the food, medical, and textile industries. However, native starch with insufficient functionality limits its utilization in the above applications; therefore, it is modified through various physical, chemical, enzymatic, genetic and multiple modifications. This review summarized the relationship between structural changes and functional properties of starch subjected to different modified methods, including hydrothermal treatment, microwave, pre-gelatinization, ball milling, ultrasonication, radiation, high hydrostatic pressure, supercritical CO₂, oxidation, etherification, esterification, acid hydrolysis, enzymatic modification, genetic modification, and their combined modifications. A better understanding of these features has the potential to lead to starch-based products with targeted structures and optimized properties for specific applications.

Solid state malic acid esterification on fungal α-amylase treated corn starch: Design of a green dual treatment

For the first time, the current work applied fungal α-amylase treated corn starch in granular form to produce solid state malate-esterified starch (MES). The pores and channels created on the granules after the enzymatic modification could provide more possibilities for malic acid to esterify the starch, resulting in the increase of substitution degree (0.084) and reaction efficiency (86.6%) compared to NS. Based on the obtained results, the dual treatment significantly increased solubility, amylose content, and syneresis, but reduced transparency, viscosity, digestibility rate, and swelling power compared to those of NS. The occurrence of esterification onto starch chains was confirmed by FT-IR at 1720 cm^-1. Other techniques including SEM, XRD, and DSC were employed to examine changes in the structure of starch granules after applying each treatment. Also, the greenness of the combined modification (score: 77) was proved by using a new methodology named Eco-Scale.

Debranching facilitates malate esterification of waxy maize starch and decreases the digestibility

In this study, the debranching followed by malate esterification was employed to prepare malate debranched waxy maize starch (MA-DBS) with a high degree of substitution (DS) and low digestibility using malate waxy maize starch (MA-WMS) as the control. The optimal esterification conditions were obtained using an orthogonal experiment. Under this condition, the DS of MA-DBS (0.866) was much higher than that of MA-WMS (0.523). A new absorption peak was generated at 1757 cm^-1 in the infrared spectra, indicating the occurrence of malate esterification. Compared with MA-WMS, MA-DBS had more particle aggregation, resulting in an increase in the average particle size from scanning electron microscopy and particle size analysis. The X-ray diffraction results showed that the relative crystallinity decreased after malate esterification, in which the crystalline structure of MA-DBS almost disappeared, which was consistent with the decrease of decomposition temperature by thermogravimetric analysis and the disappearance of the endothermic peak by differential scanning calorimeter. In vitro digestibility tests showed an order: WMS > DBS > MA-WMS > MA-DBS. The MA-DBS showed the highest content of resistant starch (RS) of 95.77 % and the lowest estimated glycemic index of 42.27. In a word, pullulanase debranching could produce more short amylose, promoting malate esterification and improving the DS. The presence of more malate groups inhibited the formation of starch crystals, increased particle aggregation, and enhanced resistance to enzymolysis. The present study provides a novel protocol for producing modified starch with higher RS content, which has potential application in functional foods with a low glycemic index.

Esterified unpopped foxnut (Euryale ferox) starch: molecular and rheological characterization

BACKGROUND

Acetylated-based starches are broadly used in the food industry as emulsifiers, and as thickening and film-forming agents. Better understanding of the structural and rheological parameters would facilitate the selection of optimal acetylated starches for particular applications. Nuclear magnetic resonance (¹ H-NMR), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) patterns, and rheological properties, including elasticity (G'), loss (G") moduli, complex viscosity (η*) and study shear stress (δ), were determined for acetylated fox nut starch (FNS) samples.

RESULTS

The degree of substitution (DS) varied significantly with increasing acetyl concentration from 2-6%. Nuclear magnetic resonance analysis of acetylated FNS showed an additional chemical shift at 2.08 ppm in comparison with native FNS, confirming the linking of the H or the -OCH3 group. The acetylated FNS starches showed better short-range ordering of molecules, as confirmed by FTIR. A significant increase in the functional and gelatinization properties with increasing acetyl concentration was observed. The power law parameters (n, K) and dynamic moduli (G' and G") increased with increasing acetyl concentration and presented shear thinning behavior. The gelatinization peak temperature and enthalpy decreased with increasing acetyl concentration.

CONCLUSION

The observed DS below 2.5 would mean safe food consumption and the significant alteration of functional and structural properties with varying acetyl content will extend the use of FNS in food and allied industries. © 2023 Society of Chemical Industry.

Advances in continuous polymer analysis in flow with application towards biopolymers

Biopolymers, polymers derived from renewable biomass sources, have gained increasing attention in recent years due to their potential to replace traditional petroleum-based polymers in a range of applications. Among the many advantages of biopolymers can be included their biocompatibility, excellent mechanical properties, and availability from renewable feedstock. However, the development of biopolymers has been limited by a lack of understanding of their properties and processing behaviours. Continuous analysis techniques have the potential to hasten progress in this area by providing real-time insights into the properties and processing of biopolymers. Significant research in polymer chemistry has focused on petroleum-derived polymers and has thus provided a wealth of synthetic and analytical methodologies which may be applied to the biopolymer field. Of particular note is the application of flow technology in polymer science and its implications for accelerating progress towards more sustainable and environmentally friendly alternatives to traditional petroleum-based polymers. In this mini review we have outlined several of the most prominent use cases for biopolymers along with the current state-of-the art in continuous analysis of polymers in flow, including defining and differentiating atline, inline, online and offline analysis. We have found several examples for continuous flow analysis which have direct application to the biopolymer field, and we demonstrate an atline continuous polymer analysis method using size exclusion chromatography.

Graphical abstract

Enzymatically preparation of starch nanoparticles using freeze drying technique - Gelatinization, optimization and characterization

Starch nanoparticles (SNPs) in colloidal forms were prepared using enzymatically pretreatment and four different gelatinization methods based on autoclave, microwave, ultrasonication and normal heating with stirring. Furthermore, SNPs in powder form were prepared using freeze drying technique. Results indicated that the formed SNPs using starch solution (1 % W/V) and ultrasonication technique had lowest mean particle size (151 nm) and PDI (0.173), and highest zeta potential (-8.8 mV) values. Optimization procedure using response surface methodology, based on central composite design, indicated that using 1.5 mL of α-amylase and sonication time of 15 min, SNPs with lowest particle size (49.3 nm) and highest zeta potential (-10.8 mV) were produced. Using prepared colloidal solution under optimal conditions, SNPs powder were produced by freeze dryer, adjusted at pressure and temperature of 100 Pa and - 70 °C, for 24 h. Results indicated that formed SNPs powder with squared-shape, had particle size, zeta potential, specific surface area, decomposition temperature of 197 nm, -13.9 mV, 1.9 m²g^-1 and 162 °C, respectively. While, for native starch these values were 5018 nm, -6.01 mV, 0.68 m²g^-1 and 170.2 °C, respectively. Results revealed that emulsification ability of SNPs powder was three times higher than that of the native starch.

The novel chitosan-amphoteric starch dual flocculants for enhanced removal of Microcystis aeruginosa and algal organic matter

A novel flocculation strategy for simultaneously removing Microcystis aeruginosa and algal organic matter (AOM) was proposed using chitosan-amphoteric starch (C-A) dual flocculants in an efficient, cost-effective and ecologically friendly way, providing new insights for harmful algal blooms (HABs) control. A dual-functional starch-based flocculant, amphoteric starch (AS) with high anion degree of substitution (DS_A) and cation degree of substitution (DS_C), was prepared using a cationic moiety of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA) coupled with an anion moiety of chloroacetic acid onto the backbone of starch simultaneously. In combination of the results of FTIR, XPS, ¹H NMR, ¹³C NMR, GPC, EA, TGA and SEM, it was evidenced that the successfully synthesized AS with excellent structural characteristics contributed to the enhanced flocculation of M. aeruginosa. Furthermore, the novel C-A dual flocculants could achieve not only the removal of >99.3 % of M. aeruginosa, but also the efficacious flocculation of algal organic matter (AOM) at optimal concentration of (0.8:24) mg/L, within a wide pH range of 3-11. The analysis of zeta potential and cellular morphology revealed that the dual effects of both enhanced charge neutralization and notable netting-bridging played a vital role in efficient M. aeruginosa removal.

The molecular structure effects of starches and starch phosphates in the reverse flotation of quartz from hematite

Native starches and their phosphates with various molecular structures was introduced as the depressant to realize the flotation of quartz from hematite in this study. The present starch phosphates (WSP, NSP, GSP) were modified by the reaction between phosphate and three different corn starches (WS, NS, G50). The synthesis and characterization of starch phosphates found that starch with high amylopectin content was easily modified into starch phosphates. Microflotation tests showed that starch phosphates exhibited stronger depressing abilities of hematite flotation than native starches. Zeta potential measurement showed that both starches and starch phosphates could positively shift the zeta potential of hematite, while starch phosphates had more effects than starches. XPS and MDS indicated that the chemisorption occurred between Fe of hematite surface and CO groups of starch-based depressants. In addition, starch phosphates could adsorb onto the hematite surface through PO groups. MDS also presented that the adsorption strength of starch phosphate was mainly determined by the type and number of generating chelating rings, and the molecular structure of starch significantly affected the formation of chelate rings. The proposed adsorption model insights will significantly promote the development of starch-based depressants for iron ore flotation and other mineral processing applications.

Effects of rice protein, soy isolate protein, and whey concentrate protein on the digestibility and physicochemical properties of extruded rice starch

Protein, as the second major component in starchy foods, is crucial for its influence on the physicochemical properties and digestibility of starch. However, the effect of different sources of protein on starch digestibility is still unclear. In this paper, the effects of different sources of proteins (rice protein: RP, soybean isolate protein: SPI, and whey concentrate protein: WPC) on structural features, digestibility, and enzyme activity of extruded rice starch were investigated. The addition of all three proteins reduced the starch digestibility of extrudates. Native SPI and WPC suppressed amyloglucosidase activity, and all three proteins exhibited stronger amyloglucosidase inhibition when hydrolyzed. The rheological properties and Fourier transform infrared spectroscopy results revealed the exogenous proteins and starch interacted through non-covalent bonds and improved the ordered structures in the extrudates. The extrusion process also facilitated the formation of a V-type structure. The sum of SDS and RS content of extrudates was negatively correlated with the content of leached amylose and positively correlated with the ratio of 1047/1022 cm^-1 . These findings suggest that the inclusion of exogenous proteins during extrusion can affect starch digestibility through mechanisms such as the interaction with starch molecules, as well as the inhibition of amylase activity. PRACTICAL APPLICATION: This result indicated that the addition of protein during extrusion not only increased the nutritional value of the extrudate, but also decreased the starch digestibility. Extrusion technology can efficiently produce extruded products with protein, expanding further applications of protein in food and providing new healthy staple food options for special populations, such as diabetic and overweight people.

The Interplay of Dietary Fibers and Intestinal Microbiota Affects Type 2 Diabetes by Generating Short-Chain Fatty Acids

Foods contain dietary fibers which can be classified into soluble and insoluble forms. The nutritional composition of fast foods is considered unhealthy because it negatively affects the production of short-chain fatty acids (SCFAs). Dietary fiber is resistant to digestive enzymes in the gut, which modulates the anaerobic intestinal microbiota (AIM) and fabricates SCFAs. Acetate, butyrate, and propionate are dominant in the gut and are generated via Wood-Ljungdahl and acrylate pathways. In pancreatic dysfunction, the release of insulin/glucagon is impaired, leading to hyperglycemia. SCFAs enhance insulin sensitivity or secretion, beta-cell function, leptin release, mitochondrial function, and intestinal gluconeogenesis in human organs, which positively affects type 2 diabetes (T2D). Research models have shown that SCFAs either enhance the release of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) from L-cells (entero-endocrine), or promotes the release of leptin hormone in adipose tissues through G-protein receptors GPR-41 and GPR-43. Dietary fiber is a component that influences the production of SCFAs by AIM, which may have beneficial effects on T2D. This review focuses on the effectiveness of dietary fiber in producing SCFAs in the colon by the AIM as well as the health-promoting effects on T2D.

Recent advances of antibacterial starch-based materials

Starch has attracted a lot of attention because it is biodegradable, renewable, nontoxic and low cost. By adding antibacterial substances to starch, starch-based materials have antibacterial properties. The composite with other materials can improve the comprehensive performance of starch-based materials, thus broadening the application field of the material. In this paper, we focus on antibacterial starch-based materials and review their preparation and applications. It was found that antibacterial starch-based materials were most widely used in packaging, followed by medicine, and the research on smart starch-based materials was relatively less. This review may provide some reference value for subsequent studies of starch-based materials.

A combined extrusion, retrogradation, and cross-linking strategy for preparing starch-based straws with desirable mechanical properties

This work developed a novel strategy for producing starch straws with desirable mechanical properties by a combination of extrusion, retrogradation, and sodium trimetaphosphate (STMP) cross-linking. The straws were prepared by first extruding starch, glycerin, and water (10:1:1) with a double screw extruder, then retrograding the resulting straws at 4 °C for 6 h, and finally cross-linking the straws. Rapid visco-analyzer profiles showed decreases in the viscosity of milled straws with increases in the cross-linking duration, perhaps reflecting a higher degree of crosslinking. Fourier transform infrared spectroscopy showed evidence of more hydrogen bonds in the straws with a longer cross-linking duration, while thermogravimetric analysis indicated higher thermal stability for the cross-linked straws than for the controls. The straw cross-linked for 3 h showed 1.52 times higher stiffness after soaking in room-temperature water for 30 min (4967.56 g/s), and 1.88 times higher stiffness after soaking in 60 °C hot water for 5 min (5371.89 g/s) than the original straw. STMP cross-linking also improved the starch straw mechanical properties after soaking in common soft drinks. These findings identify a potential new way to produce biodegradable straws with desirable properties from starch, an affordable biomaterial, while also addressing the problem of petroleum-based plastic pollution.

The development of a semisynthetic diet deficient in methionine for adult cats for controlled feline nutrition studies: effects on acceptability, preference, and behavior responses

Chemically defined diets are commonly used in amino acid (AA) requirement studies to allow for tight control of AA delivery. However, those diets are not representative of commercial diets in the market and are unpalatable. Methionine (Met) is usually the first limiting AA in cat diets, but little is known about its requirement for adult cats. Thus, the objectives of this study were: 1) to develop a semisynthetic diet limiting in Met and evaluate its effect on acceptance and feeding behavior in cats; and 2) to evaluate the effect of different sources and inclusions of Met on preference in cats fed the semisynthetic diet. A semisynthetic diet deficient in Met and total sulfur AA (TSAA) was developed. Healthy adult male cats (n = 9) were fed (0800 and 1600 h) the semisynthetic diet top dressed with DL-Met solution (T-DLM), to meet 120% of the TSAA requirement, for 8 d. Feed intake was measured and a 30-min video recording was taken at the 0800 h feeding to evaluate feeding behavior of the cats. Following the acceptability trial, two bowl tests were performed where first choice was recorded and intake ratio was calculated as consumed food (A/A + B). Three combinations were tested: semisynthetic diet deficient in Met (T-BASAL) vs. T-DLM; T-BASAL vs. diet sufficient in Met provided 2-hydroxy-4-(methylthio)-butanoic acid (T-MHA); and T-DLM vs. T-MHA. Average feed intake remained high throughout the acceptability period (94.5% intake of total offered), but some cats decreased intake, resulting in a decrease in BW (≤2.5% of initial BW) over time (P < 0.05). Behaviors were similar among days (P > 0.05) with the exception of grooming the chest and body (P < 0.05). No preferences were observed towards a specific treatment (Met source and level) during the two-bowl tests (P > 0.05) and agreed with the cats expressing similar feeding behaviors during the preference tests (P > 0.05). In conclusion, a semisynthetic diet deficient in Met was successfully developed and can be used in studies to evaluate the effects of low protein and AA supplemented diets. Cats seem to show no preference for Met source and/or inclusion level in a semisynthetic diet application, which is of benefit for future studies aiming to determine the Met requirement in this species.