Modification methods toward the production of porous starch: a review

Green fabrication of hierarchical pore starch with controllable pore size and shape based on different amylose-amylopectin ratios

Porous starch (PS) was widely prepared for its large effective surface area, pore volume, and superior hydrophilic property, but its application is limited by enzyme and chemical use. In this study, a novel method to prepare PS with controllable hierarchical pores through ultrasound-ethanol precipitation and different amylose-amylopectin ratios is proposed. As shown in porous morphology and parameters, there were macropores, mesopores and micropores in the formed PS. Moreover, we found that the content of amylose (AM) was negatively related with the total pore volume and pore diameter in PS. The different surface tensions created through ethanol evaporation and water migration during oven drying are the main mechanisms of forming pores with controllable sizes. Based on the molecular information and the long-/short-range orders reflected by crystalline pattern, lamellas, and single-/double-helices, we conclude that AM is easier to form V-type inclusion complexes with ethanol. More single helix of V-amylose was transformed from B-type polymorph after ethanol exchange, which had significantly broadened dLozentz in PS. The TG spectra proved that the novel PS has the stable thermodynamic property. Overall, the finding of an objective regular between AM and pore sizes of PS in this study may support the other work related to PS.

Synthesis and characterization of etherified cationic starch flocculant derived from Manihot esculenta peel with varying degrees of substitution

Cationic Manihot esculenta (ME) peel starch was synthesized through etherification method using 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) as cationizing monomer. The optimization of the main factors influencing the degree of substitution (DS) was conducted using central composite design (CCD) and response surface methodology (RSM). The factors assessed include CHPTAC concentration, catalyst sodium hydroxide (NaOH) concentration, and reaction time. The DS values of the cationic starches were obtained between 0.39 and 0.99. The maximum DS value was up to 0.99 at 0.615 mol/L of CHPTAC, 30 % (w/v) NaOH, and a reaction time of 5 h. The finding based on the optimization using RSM reflected that CHPTAC and NaOH concentrations are the key variables determining the DS value, while reaction time has a negligible impact on the etherification process. Furthermore, the chemical composition, morphology, and structure of the cationic ME peel starch were characterized by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and nuclear magnetic resonance spectroscopy (1H NMR). It was confirmed that the modifying monomers penetrated the surface layer of the starch granules and attached to the starch backbone.

Heterologous expression, characterization, and application of recombinant thermostable α-amylase from Geobacillus sp. DS3 for porous starch production

Novel Geobacillus sp. DS3, isolated from the Sikidang Crater in Dieng, exhibits promising characteristics for industrial applications, particularly in thermostable α-amylase production. Recombinant technology was used to express thermostable α-amylase in E. coli BL21(DE3) to overcome high-temperature production challenges. The study aimed to express, purify, characterize, and explore potential applications of this novel enzyme. The enzyme was successfully expressed in E. coli BL21(DE3) at 18 °C for 20 h with 0.5 mM IPTG induction. Purification with Ni-NTA column yielded 69.23 % from the initial crude enzyme, with a 3.6-fold increase in specific activity. The enzyme has a molecular weight of ±70 kDa (±58 kDa enzyme+11 kDa SUMO protein). It exhibited activity over a wide temperature range (30-90 °C) and pH range (6-8), with optimal activity at 70 °C and pH 6 with great stability at 60 °C. Kinetic analysis revealed Km and Vmax values of 324.03 mg/ml and 36.5 U/mg, respectively, with dextrin as the preferred substrate without cofactor addition. As a metalloenzyme, it showed the best activity in the presence of Ca2+. The enzyme was used for porous starch production and successfully immobilized with chitosan, exhibiting improved thermal stability. After the fourth reuse, the immobilized enzyme maintained 62 % activity compared to the initial immobilization.

In vitro fecal fermentation of acylated porous Canna edulis starch and corresponding stabilized Pickering emulsions

In this study, acylated porous Canna edulis starch with varying degrees of substitution (DS) were prepared and employed for stabilizing Pickering emulsions. Subsequently, the fermentation characteristics of them were investigated. Enzymatically produced porous starch (PS) was esterified with acetic, propionic, butyric, or valeric anhydrides, yielding acetylated (PSA-0.116), propionylated (PSP-0.163), butyrylated (PSB-0.304), and valerylated PS (PSV-0.462) with different DS. Scanning electron microscopy revealed the presence of pores and surface micro-particles in the modified PS, confirming successful esterification through characteristic peaks in 1H NMR and a CO peak at 1736 cm-1 in the FT-IR spectrum. With increasing DS, starch exhibited reduced crystallinity (PSV, 26.61 %), elevated resistant starch content (PSV, 91.63 %), and a higher contact angle (PSV, 87.13°). Acylated PS particles effectively stabilized Pickering emulsions. Pickering emulsions stabilized by acylated PS with higher DS exhibited higher emulsification index and smaller droplet sizes. In vitro fermentation of acylated PS and corresponding stabilized Pickering emulsions fostered short-chain fatty acid production, boosted the relative abundance of beneficial bacteria (Bifidobacterium, Prevotella, etc.) while inhibited the growth of harmful bacteria (Escherichia-Shigella, Comamonas, etc.), maintaining the intestinal microbiota balance. These findings support the potential applications of acylated PS and corresponding stabilized Pickering emulsions in functional foods and drug delivery.

Effect of different drying methods on the structure and properties of porous starch

In order to investigate the effects of different drying methods on the properties of porous starch. The present study used four drying methods, namely hot air drying (HD), spray drying (SPD), vacuum freeze drying (FD) and supercritical carbon dioxide drying (SCD) to prepare maize and kudzu porous starch. Findings indicated that the physicochemical properties (e.g., morphology, crystallinity, enthalpy value, porosity, surface area and water absorption capacity as well as dye absorption capacity, particle size) of porous starch were significantly affected by the drying method. Compared with other samples, SCD-treated porous starch exhibited the highest surface areas of the starch (2.943 and 3.139 m2/g corresponding to kudzu and maize, respectively), amylose content (22.02 % and 16.85 % corresponding to kudzu and maize, respectively), MB and NR absorption capacity (90.63 %, 100.26 % and 90.63 %, 100.26 %, corresponding to kudzu ad maize, respectively), and thermal stability, whereas HD-treated porous starch showed the highest water-absorption capacity (123.8 % and 131.31 % corresponding to kudzu and maize, respectively). The dye absorption of the maize and kudzu porous starch was positively correlated with surface area, according to Pearson's correlation analysis. Therefore, in this study, our aim was to explore the effects of different drying methods on the Structure and properties of porous starch, and provide reference for selecting the best drying method for its application in different fields.

The art and science of porous starch: understanding the preparation method and structure-function relationship

Porous starch (PS), a modified form of starch with unique properties, is attracting substantial attention for its diverse advantages and applications. Its intricate porous structure, crystalline and amorphous characteristics, and hydrophilic-hydrophobic properties stem from pore formation via physical, chemical, enzymatic, and combined synergistic methods. Porous starch offers benefits like improved gelatinization temperature, water absorption, increased surface area, tunable crystallinity, and enhanced functional properties, making it appealing for diverse food industry applications. To optimize its properties, determining the parameters governing porous structure formation is crucial. Factors such as processing conditions, starch source, and modification methods substantially impact porosity and the overall characteristics of the material. Understanding and controlling these parameters allows customization for specific applications, from pharmaceutical drug delivery systems to enhancing texture and moisture retention in food products. To date, studies shedding light on how porosity formation can be fine-tuned for specific applications are fewer. This review critically assesses the existing reports on porous starch, focusing on how preparation methods affect porosity formation, thereby influencing the product's crystallinity/hydrophilic-hydrophobic nature and overall applicability.

Investigation of the formation mechanism of the pepper starch-piperine complex

In this study, a new carrier for loading piperine was prepared using pepper starch, and its interaction mechanism was investigated. The porous pepper starch-piperine complex (PPS-PIP) showed higher loading efficiency (76.15 %) compared to the porous corn starch-piperine complex (PCS-PIP (52.34 %)). This may be ascribed to the hemispherical shell structure of porous pepper starch (PPS) compared to the porous structure of porous corn starch (PCS) based on the SEM result. PPS-PIP had smaller particle size (10.53 μm), higher relative crystallinity (38.95 %), and better thermal stability (87.45 °C) than PCS-PIP (17.37 μm, 32.17 %, 74.35 °C). Fourier transform infrared spectroscopy (FTIR) results implied that piperine not only forms a complex with amylose but may also be physically present in porous starch. This was demonstrated by the short-range order and X-ray type. Molecular dynamics simulations confirmed that hydrogen bonding is the primary interaction between amylose and piperine. Besides the formation of the amylose-piperine complex, some of the piperine is also present in physical form.

Potential use of Thai mango (Mangifera indica Linn. cultivar Chok-Anan) seed porous starch for retention of aroma compounds from coffee extract

This study aimed to extract and modify the properties of the starch from Thai mango seeds (cultivar Chok-Anan). The porous starch samples were obtained using enzymatic treatment and its potential to retain aroma compounds from coffee extract was evaluated. The physicochemical properties, structure characteristics, porosity characteristics and adsorption quantity of starches were also determined. The retention of coffee aroma compounds was investigated through combining starch or porous starch with odorants, and storing the mixtures at room temperature for 7 and 14 days, respectively. The chemical properties of aroma compounds as well as starch surface properties were observed to affect the retention of aroma compounds upon storage. Additionally, 2-furanmethanol, d-limonene and maltol were selected to be the primary target compounds to assess the retention of odorants. This study observed a noticeable decrease in d-limonene content throughout the storage period. On the contrary, after 14 days of storage, the porous starch exhibited high retention of hydroxy compounds including 2-furanmethanol and maltol. However, after prolonged storage their ability to retain 2-furanmethanol and maltol slightly decreased. Therefore, the porous starch derived from mango seeds exhibited the potential to retain coffee aroma compounds and could be a desirable green adsorbent for food and cosmetic industries.

Understanding the improvement of sorghum starch acid hydrolysis modification by E-beam irradiation: A supramolecular structure perspective

To investigate the effect of E-beam irradiation (EBI) on acid-hydrolyzed starch, sorghum starch was pretreated with EBI (2, 4, and 8 kGy) and further hydrolyzed using hydrochloric acid (1 % and 6 % concentrations) in this study. EBI intensified acid hydrolysis corrosion on starch granule surfaces without inducing changes in the growth ring, FT-IR spectra, and crystal type (A-type). Also, EBI promoted starch degradation by acid hydrolysis, as evidenced by the R1047/1022 loss (1.071 to 1.027), the molecular weight decrease, and the chain length distribution shift (toward short A-chain). Moreover, this synergistic modification induced a starch enthalpy decrease (only 9.49 J/g) and crystallinity reduction (29.87 %), while solubility increase (34.27 %) and swelling power inhibition (only 7.65 g/g) were observed. Notably, starch digestibility was improved after synergistic modification. The obtained results broaden the processing depth of EBI in modified starch and highlight the promising application of acidolysis sorghum starch as a potential industrial starch.

Formation, influencing factors, and applications of internal channels in starch: A review

Starch, a natural polymer, has a complex internal structure. Some starches, such as corn and wheat starches, have well-developed surface pores and internal channels. These channel structures are considered crucial in connecting surface stomata and internal cavities and have adequate space for loading guest molecules. After processing or modification, the starch-containing channel structures can be used for food and drug encapsulation and delivery. This article reviews the formation and determination of starch internal channels, and the influence of different factors (such as starch species and processing conditions) on the channel structure. It also discusses relevant starch preparation methods (physical, chemical, enzymatic, and synergistic), and the encapsulation effect of starch containing internal channels on different substances. In addition, the role of internal channels in regulating the starch digestion rate and other aspects is also discussed here. This review highlights the significant multifunctional applications of starch with a channel structure.

Physicochemical Characteristics of Porous Starch Obtained by Combined Physical and Enzymatic Methods, Part 1: Structure, Adsorption, and Functional Properties

Porous starch can be applied as an adsorbent and encapsulant for bioactive substances in the food and pharmaceutical industries. By using appropriate modification methods (chemical, physical, enzymatic, or mixed), it is possible to create pores on the surface of the starch granules without disturbing their integrity. This paper aimed to analyze the possibility of obtaining a porous structure for native corn, potato, and pea starches using a combination of ultrasound, enzymatic digestion, and freeze-drying methods. The starch suspensions (30%, w/w) were treated with ultrasound (20 kHz, 30 min, 20 °C), then dried and hydrolyzed with amyloglucosidase (1000 U/g starch, 50 °C, 24 h, 2% starch suspension). After enzyme digestion, the granules were freeze-dried for 72 h. The structure of the native and modified starches were examined using VIS spectroscopy, SEM, ATR-FTIR, and LTNA (low-temperature nitrogen adsorption). Based on the electrophoretic mobility measurements of the starch granules using a laser Doppler velocimeter, zeta potentials were calculated to determine the surface charge level. Additionally, the selected properties such as the water and oil holding capacities, least gelling concentration (LGC), and paste clarity were determined. The results showed that the corn starch was the most susceptible to the combined modification methods and was therefore best suited for the production of porous starch.

Effect of ethanol, phytic acid and citric acid treatment on the physicochemical and heavy metal adsorption properties of corn starch

Corn starch dispersions were heated with ethanol (E) and reacted with phytic acid (E-PA), citric acid (E-CA), and a mixture of phytic and citric acid (E-PACA) under dry-heating to prepare heavy metal adsorbents. Microscopy images indicated that ethanol treatment induced the formation of porous structures on the surface; furthermore, treatment with phytic and citric acid induced indentations, pores, and irregular structures in E-PA, E-CA, and E-PACA starches. Phytic and citric acid were retained in the starch molecules through ester bonds with the phosphate and carboxyl groups, respectively. Starch esterification by phytic and citric acid induced a loss of crystallinity, high water absorption capacity, and low solubility. E-PACA starch exhibited more efficient Cu2+ adsorption (38.13 mg/g) than native, E, E-PA, and E-CA starches (0.11, 0.49, 2.05, and 36.23 mg/g, respectively). Thus, modification with ethanol, phytic acid and citric acid can be applied to prepare natural starch-based heavy metal adsorbents.

Expanded porous-starch matrix as an alternative to porous starch granule: Present status, challenges, and future prospects

Exposing the hydrated-soft-starch matrix of intact grain or reconstituted flour dough to a high-temperature-short-time (HTST) leads to rapid vapor generation that facilitates high-pressure build-up in its elastic matrix linked to large deformation and expansion. The expanded starch matrix at high temperatures dries up quickly by flash vaporization of water, which causes loss of its structural flexibility and imparts a porous and rigid structure of the expanded porous starch matrix (EPSM). EPSM, with abundant pores in its construction, offers adsorptive effectiveness, solubility, swelling ability, mechanical strength, and thermal stability. It can be a sustainable and easy-to-construct alternative to porous starch (PS) in food and pharmaceutical applications. This review is a comparative study of PS and EPSM on their preparation methods, structure, and physicochemical properties, finding compatibility and addressing challenges in recommending EPSM as an alternative to PS in adsorbing, dispersing, stabilizing, and delivering active ingredients in a controlled and efficient way.

Fabrication and study on dually modified starch embedded in alginate hydrogel as an encapsulation system for Satureja essential oil

This study aimed to investigate how the types and order of modifications influence the structure and physicochemical characteristics of modified porous starch. The work focuses on the encapsulation of essential oil in hydrophobic microcapsules embedded in sodium alginate hydrogels. FTIR spectra indicated successful esterification of starch with OSA. 1047:1022 cm-1 and 1022:995 cm-1 band ratios of FTIR spectra revealed increased crystallinity due to enzymatic modification, supported by XRD patterns. Porous-OSA (PO) starch had 1.5 times higher degree of substitution (DS) than OSA-porous (OP) starch, confirmed by the intense peak at 0.85 ppm in 1H NMR spectra. SEM images displayed larger particles and smaller pore diameter in OP compared to PO and porous starch, indicating amylolytic enzyme inhibition by OSA. Loading efficiency (LE) showed no significant difference between OP and PO microcapsules (≈70 %), both significantly higher other starch microcapsules. OP and PO microcapsules exhibited sustained release, with enhanced antibacterial activity. Alginate hydrogels preserved about 60 % antioxidant and 90 % antibacterial activities of SEO against 2 h of UV radiation. These findings suggest that the order of modification could not affect the functional properties of final microcapsules. Additionally, the importance of alginate hydrogels as the protective and second wall material was disclosed.

Colon targeted releases and uptakes of paclitaxel loaded in modified porous starch

Hyaluronic acid can modify porous starch through cross-linking and hydrogen bonding, effectively achieving a paclitaxel entrapment efficiency of ∼92 % and drug loading of ∼23 %. In this study, the pores and intergranular gaps of porous starch were filled with paclitaxel under solvent volatilization, and the enrichment process and its characteristics were recorded using a microscope. The paclitaxel-loaded particles were coated with chitosan-phytic acid to target the colon. In vivo imaging in mice showed that the capsule released paclitaxel in the colon rather than in the upper digestive tract, and the paclitaxel distribution in the main organs at 24 h was significantly lower than that of raw paclitaxel. Hyaluronic acid-modified porous starch can target cancer cells. Cell internalization of paclitaxel mediated by hyaluronic acid was approximately 1.97 times that of raw paclitaxel, higher than that of receptor-shielded cells and cells incubated with unmodified carriers, as evidenced by the accumulation of fluorescent paclitaxel in the nucleus and marked cell apoptosis. The hyaluronic acid-modified porous starch system is an effective method for the high-load and targeted release of hydrophobic anticancer drugs.

Dextranase Production Using Marine Microbacterium sp. XD05 and Its Application

Dextranase, also known as glucanase, is a hydrolase enzyme that cleaves α-1,6 glycosidic bonds. In this study, a dextranase-producing strain was isolated from water samples of the Qingdao Sea and identified as Microbacterium sp. This strain was further evaluated for growth conditions, enzyme-producing conditions, enzymatic properties, and hydrolysates. Yeast extract and sodium chloride were found to be the most suitable carbon and nitrogen sources for strain growth, while sucrose and ammonium sodium were found to be suitable carbon and nitrogen sources for fermentation. The optimal pH was 7.5, with a culture temperature of 40 °C and a culture time of 48 h. Dextranase produced by strain XD05 showed good thermal stability at 40 °C by retaining more than 70% relative enzyme activity. The pH stability of the enzyme was better under a weak alkaline condition (pH 6.0-8.0). The addition of NH4+ increased dextranase activity, while Co2+ and Mn2+ had slight inhibitory effects on dextranase activity. In addition, high-performance liquid chromatography showed that dextran is mainly hydrolyzed to maltoheptanose, maltohexanose, maltopentose, and maltootriose. Moreover, it can form corn porous starch. Dextranase can be used in various fields, such as food, medicine, chemical industry, cosmetics, and agriculture.

Ultrasound-assisted acid/enzymatic hydrolysis preparation of loquat kernel porous starch: A carrier with efficient palladium loading capacity

Porous starch, with excellent renewal and thermodynamic stability characteristics, could be utilized as a novel carrier for metals. In this research, starch was obtained from wasted loquat kernel (LKS) and converted into loquat kernel porous starch (LKPS) through ultrasound-assisted acid/enzymatic hydrolysis. Then, LKS and LKPS were utilized for loading with palladium. The porous structures of LKPS were evaluated by the results of water/oil absorption rate and N2 adsorption analysis, and the physicochemical properties of LKPS and starch@Pd were analyzed by FT-IR, XRD, SEM-EDS, ICP-OES, and DSC-TAG. LKPS prepared by the synergistic method formed a better porous structure. Its specific surface area was 2.65 times that of LKS, and the water/oil absorption capabilities were considerably improved to 152.28 % and 129.59 %, respectively. XRD patterns showed that the presence of diffraction peaks at 39.7° and 47.1°, indicating successful palladium loading onto LKPS. The EDS and ICP-OES results revealed that the palladium loading capacity of LKPS was superior to that of LKS, with a significantly increased loading ratio of 2.08 %. In addition, LKPS@Pd exhibited excellent thermal stability, with a temperature range of 310-320 °C. Therefore, LKPS was a palladium carrier with highly efficient loading ratio, and LKPS@Pd had promising properties as a competent catalyst.

Structural and Functional Properties of Porous Corn Starch Obtained by Treating Raw Starch with AmyM

Porous starch is attracting considerable attention for its high surface area and shielding ability, properties which are useful in many food applications. In this study, native corn starch with 15, 25, and 45% degrees of hydrolysis (DH-15, DH-25, and DH-45) were prepared using a special raw starch-digesting amylase, AmyM, and their structural and functional properties were evaluated. DH-15, DH-25, and DH-45 exhibited porous surface morphologies, diverse pore size distributions and pore areas, and their adsorptive capacities were significantly enhanced by improved molecular interactions. Structural measures showed that the relative crystallinity decreased as the DH increased, while the depolymerization of starch double helix chains promoted interactions involving disordered chains, followed by chain rearrangement and the formation of sub-microcrystalline structures. In addition, DH-15, DH-25, and DH-45 displayed lower hydrolysis rates, and DH-45 showed a decreased C∞ value of 18.9% with higher resistant starch (RS) content and lower glucose release. Our results indicate that AmyM-mediated hydrolysis is an efficient pathway for the preparation of porous starches with different functionalities which can be used for a range of applications.

Oral delivery of porous starch-loaded bilayer microgels for controlled drug delivery and treatment of ulcerative colitis

We prepared one type of bilayer microgels for oral administration with three effects: pH responsiveness, time lag, and colon enzyme degradation. Combined with the dual biological effects of curcumin (Cur) for reducing inflammation and promoting repair of colonic mucosal injury, targeted colonic localization and release of Cur according to the colonic microenvironment were enhanced. The inner core, derived from guar gum and low-methoxyl pectin, afforded colonic adhesion and degradation behavior; the outer layer, modified by alginate and chitosan via polyelectrolyte interaction, achieved colonic localization. The porous starch (PS)-mediated strong adsorption allowed Cur loading in inner core to achieve a multifunctional delivery system. In vitro, the formulations exhibited good bioresponses at different pH conditions, potentially delaying Cur release in the upper gastrointestinal tract. In vivo, dextran sulfate sodium-induced ulcerative colitis (UC) symptoms were significantly alleviated after oral administration, accompanied by reduced levels of inflammatory factors. The formulations facilitated colonic delivery, allowing Cur accumulation in colonic tissue. Moreover, the formulations could alter gut microbiota composition in mice. During Cur delivery, each formulation increased species richness, decreased pathogenic bacterial content, and afforded synergistic effects against UC. These PS-loaded bilayer microgels, exhibiting excellent biocompatibility, multi-bioresponsiveness, and colon targeting, could be beneficial in UC therapy, allowing development into a novel oral formulation.

Modified porous starch for enhanced properties: Synthesis, characterization and applications

Native starches have low water solubility at room temperature and poor stability, which demand modifications to overcome. Porous starch as a modified one shows enhanced adsorptive efficiency and solubility compared with its native starch. In contrast, some inherent disadvantages exist, such as weak mechanical strength and low thermal resistance. Fortunately, modified porous starches have been developed to perform well in adsorption capacity and stability. Modified porous starch can be prepared by esterification, crosslinking, oxidation and multiple modifications to the porous starch. The characterization of modified porous starch can be achieved through various analytical techniques. Modified porous starch can be utilized as highly efficient adsorbents and encapsulants for various compounds and applied in various fields. This review dealt with the progress in the preparation, structural characterization and application of modified porous starch. The objective is to provide a reference for its development, utilization, and future research directions.

Insight into structure-activity relationships of hydroxycinnamic acids modified porous starch: The effect of phenolic hydroxy groups

Antioxidant capacity of hydroxycinnamic acids-modified starch mainly depends on their chemical structure. Herein, cinnamic acid as well as meta-substituted and para-substituted cinnamic acid were selected for esterification with porous starch (labelled as CA@PS, m-CA@PS and p-CA@PS), with the successful formation of porous starch (labelled as PS) esters then confirmed by ¹H NMR, ¹³C solid-state NMR and FT-IR spectroscopy. Three PS esters with almost same degrees of substitution (DS) were obtained, and antioxidant assays, including DPPH radical scavenging, reducing power and hydroxyl radical scavenging tests, were subsequently used to evaluate the antioxidant activity of the esterified PS. Overall, CA@PS showed weak antioxidant activity because of the absence of phenolic hydroxy, while p-CA@PS displayed better antioxidant capacity. Because its conjugated structure offered the stronger electron-donating effect, that could enhance antioxidant capacity. Therefore, antioxidant capacity depended significantly on overall chemical structure, including numbers and substitution positions of phenolic hydroxy groups.

Porous corn starch obtained from combined cold plasma and enzymatic hydrolysis: Microstructure and physicochemical properties

The combined effect of cold plasma treatment and enzymatic hydrolysis was investigated on the physicochemical and microstructural properties of porous corn starch. Scanning electron microscopy (SEM) images depicted that the combined treatment led to the creation of deeper pores on the surface of starch granules. The combined treatment indicated the highest swelling power (19.49 g/g), solubility (10.08 %), specific surface area (2.97 m²/g) and total pore volume (10.47 cm³/g). According to the X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC), the combined treatment, compared with the enzymatic hydrolysis, decreased the starch crystallinity, the order of the double-helix structure, and the starch gelatinization enthalpy. The rapid visco analyzer (RVA) pasting profile revealed that the combined treatment elevated the breakdown and setback viscosities. This study indicated that cold plasma pretreatment, as a green non-thermal technology, facilitated the performance of enzymes, resulting in the production of a porous starch with a higher absorption capacity.

Freeze Moisture Treatment and Ozonation of Adlay Starch (Coix lacryma-jobi): Effect on Functional, Pasting, and Physicochemical Properties

Adlay starch has great potential as a cereal starch, but it has several weaknesses, namely a low swelling volume, low solubility, and low stability. The purpose of this study was to improve the characteristics of adlay starch, such as porosity, functional properties, and pasting properties, through starch modification using freeze moisture treatment (FMT) and ozonation. This study consisted of several treatments, namely FMT, ozonation, and a combination of FMT + ozonation. The results show that the FMT and ozonation generally increased water absorption capacity, swelling volume, solubility, and number of pores of the starch granule. The pasting properties showed an increase in the viscosity of the hot paste and caused a decrease in the gelatinization temperature, breakdown, and setback viscosity. FMT 70% + ozonation produced modified adlay starch with a porous granular surface, swelling volume value of 21.10 mL/g, water absorption capacity of 1.54 g/g, a solubility of 9.20%, and an increase in the amorphous structure but did not cause the emergence of new functional groups. The combination of FMT + ozonation was effective in improving the functional, pasting, and physicochemical properties of adlay starch.

Effects of Enzymatic Modification and Cross-Linking with Sodium Phytate on the Structure and Physicochemical Properties of Cyperus esculentus Starch

In this study, C. esculentus porous starch (PS) and C. esculentus cross-linked porous starch (CPS) were prepared by enzymatic modification and sodium phytate cross-linking, and their physicochemical and structural properties were determined. The results showed that the adsorption and emulsification capacities of PS were 1.3606 g/g and 22.6 mL/g, respectively, which were significantly higher than 0.5419 g/g and 4.2 mL/g of C. esculentus starch (NS). The retrogradation curves of starch paste showed that the stability of PS was inferior to that of NS. In addition, the results of texture analysis showed that the gel strength of PS was also significantly reduced relative to NS. The PS exhibited a rough surface with pores and low molecular order and crystallinity according to scanning electron microscope (SEM), fourier infrared spectroscopy (FTIR), and X ray diffractometer (XRD) analyses. As compared to PS, CPS still presented a high adsorption capacity of 1.2744 g/g and the steadiness of starch paste was significantly better. XPS demonstrated the occurrence of the cross-linking reaction. Our results show that enzyme modification and dual modification by combining enzymatic treatment with sodium phytate cross-linking can impart different structures and functions to starch, creating reference material for the application of modified starch from C. esculentus.

Development of Starch-Based Materials Using Current Modification Techniques and Their Applications: A Review

Starch is one of the most common biodegradable polymers found in nature, and it is widely utilized in the food and beverage, bioplastic industry, paper industry, textile, and biofuel industries. Starch has received significant attention due to its environmental benignity, easy fabrication, relative abundance, non-toxicity, and biodegradability. However, native starch cannot be directly used due to its poor thermo-mechanical properties and higher water absorptivity. Therefore, native starch needs to be modified before its use. Major starch modification techniques include genetic, enzymatic, physical, and chemical. Among those, chemical modification techniques are widely employed in industries. This review presents comprehensive coverage of chemical starch modification techniques and genetic, enzymatic, and physical methods developed over the past few years. In addition, the current applications of chemically modified starch in the fields of packaging, adhesives, pharmaceuticals, agriculture, superabsorbent and wastewater treatment have also been discussed.