High-amylose maize starch: Structure, properties, modifications and industrial applications

Spatially selective catalysis of OSA starch for preparation of Pickering emulsions with high emulsification properties

The traditional strategies of chemical catalysis and biocatalysis for producing octenyl succinic anhydride modified starch can only randomly graft hydrophobic groups on the surface of starch, resulting in unsatisfactory emulsification performance. In this work, a lipase-inorganic hybrid catalytic system with multi-scale flower like structure is designed and applied to spatially selective catalytic preparation of ocenyl succinic anhydride modified starch. With the appropriate floral morphology and petal density, lipases distributed in the "flower center" can selectively catalyze the grafting of hydrophobic groups in a spatial manner, the hydrophobic groups are concentrated on one side of starch particles. The obtaining OSA starch exhibits excellent emulsifying property, and the pickering emulsion has good protective effect on the embedded curcumin. This work provides a direction for the development of high-performance starch-based emulsifiers for the food and pharmaceutical industries, which is of great significance for improving the preparation and emulsification theory research of modified starch.

Heat-moisture treatment of freshly harvested high-amylose maize kernels improves its starch thermal stability and enzymatic resistance

The objective of this work was to study the effects of heat-moisture treatment (HMT) of freshly harvested mature high-amylose maize (HAM) kernels on its starch structure, properties, and digestibility. Freshly harvested HAM kernels were sealed in Pyrex glass bottles and treated at 80 °C, 100 °C, or 120 °C. HMT of HAM kernels had no impact on its starch X-ray diffraction pattern but increased the relative crystallinity. This result together with the increased starch gelatinization temperatures and enthalpy change indicated starch molecules reorganization forming long-chain double-helical crystalline structure during HMT of HAM kernels. The aggregation of starch granules were observed after HMT, indicating interaction of starch granules and other components. This interaction and the high-temperature crystalline structure led to reductions in the starch digestibility, swelling power, solubility, and pasting viscosity of the HAM flours. Some starch granules remained intact and showed strong birefringence after the HAM flours were precooked at 100 °C for 20 min and followed by enzymatic hydrolysis, and the amount of undigested starch granules increased with increasing HMT temperatures. This result further supported that HMT of HAM kernels with high moisture level could increase the starch thermal stability and enzymatic resistance.

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.

Effects of synchronous intermissive multi-ultrasound and esterification dual modification on functionalities of starch and its emulsion stabilization ability

Dodecenylsuccinic anhydride (DDSA) has been widely used to obtain amphiphilic starches. In this study, we investigated the functionalities of synchronous intermissive multi-ultrasound-assisted esterified starch. Compared to native starch (NS), it was deduced that multi-ultrasound-modified starch (US), esterified starch (ES), and multi-ultrasound-assisted esterified starch (UES) exhibited increased viscosities but reduced gelatinization temperatures and thermal stabilities. The viscoelastic moduli, retrogradation behaviors and hydrophobicity of the ES and UES species significantly altered. Moreover, the results of structural characterization suggested that esterification reduced the molecular weight and structural order of starch, whereas the intermissive ultrasonication treatment did not aggravate the structural disruption of ES. Additionally, compared with NS and US, the emulsification abilities of the ES and UES specimens were improved, leading to the desirable effect of stabilizing astaxanthin. Overall, this study provides a method for preparing amphiphilic starch, which can be exploited as a potential emulsifier and emulsion stabilizer for bioactive compounds.

New insights into starch, lipid, and protein interactions - Colon microbiota fermentation

Starch, lipids, and proteins are essential biological macromolecules that play a crucial role in providing energy and nutrition to our bodies. Interactions between these macromolecules have been shown to impact starch digestibility. Understanding and controlling starch digestibility is a key area of research. Investigating the mechanisms behind the interactions of these three components and their influence on starch digestibility is of significant practical importance. Moreover, these interactions can result in the formation of resistant starch, which can be fermented by gut microbiota in the colon, leading to various health benefits. While current research has predominantly focused on the digestive properties of starch in the small intestine, there is a notable gap in understanding the colonic microbial fermentation phase of resistant starch. The benefits of fermentation of resistant starch in the colon may outweigh its glucose-lowering effect in the small intestine. Thus, it is crucial to study the fermentation behavior of resistant starch in the colon. This paper investigates the impact of interactions among starch, lipids, and proteins on starch digestion, with a specific focus on the fermentation phase of indigestible carbohydrates in the colon. Furthermore, valuable insights are offered for guiding future research endeavors.

Genome-wide association analysis and transgenic characterization for amylose content regulating gene in tuber of Dioscorea zingiberensis

BACKGROUND

Amylose, a prebiotic found in yams is known to be beneficial for the gut microflora and is particularly advantageous for diabetic patients' diet. However, the genetic machinery underlying amylose production remains elusive. A comprehensive characterization of the genetic basis of amylose content in yam tubers is a prerequisite for accelerating the genetic engineering of yams with respect to amylose content variation.

RESULTS

To uncover the genetic variants underlying variation in amylose content, we evaluated amylose content in freshly harvested tubers from 150 accessions of Dioscorea zingibensis. With 30,000 high-quality single nucleotide polymorphisms (SNP), we performed a genome-wide association analysis (GWAS). The population structure analysis classified the D. zingiberensis accessions into three groups. A total of 115 significant loci were detected on four chromosomes. Of these, 112 significant SNPs (log10(p) = 5, q-value < 0.004) were clustered in a narrow window on the chromosome 6 (chr6). The peak SNP at the position 75,609,202 on chr6 could explain 63.15% of amylose variation in the population and fell into the first exon of the ADP-glucose pyrophosphorylase (AGPase) small subunit gene, causing a non-synonymous modification of the resulting protein sequence. Allele segregation analysis showed that accessions with the rare G allele had a higher amylose content than those harboring the common A allele. However, AGPase, a key enzyme precursor of amylose biosynthesis, was not expressed differentially between accessions with A and G alleles. Overexpression of the two variants of AGPase in Arabidopsis thaliana resulted in a significantly higher amylose content in lines transformed with the AGPase-G allele.

CONCLUSIONS

Overall, this study showed that a major genetic variant in AGPase probably enhances the enzyme activity leading to high amylose content in D. zingiberensis tuber. The results provide valuable insights for the development of amylose-enriched genotypes.

Heat-moisture and acid treatments can increase levels of resistant starch in arrowroot starch without adversely affecting its prebiotic activity in human colon microbiota

Carbohydrates are an important macronutrient whose processing and digestive fate can have numerous beneficial or adverse effects on consumer health. This study investigated the impact of heat-moisture treatments (HMT) and citric acid treatments (CAT) on arrowroot starch (ARS) with a focus on its physicochemical properties, digestibility, and influence on gut microbiota. The results revealed that HMT and CAT did not alter the colloidal characteristics of ARS but significantly affected the balance between amorphous and crystalline regions. Changes in thermal properties, morphology, and particle size were also observed. These can influence ARS shelf life and functional properties in various food applications. Furthermore, certain treatments in both processing methods increased the resistant starch (RS) content of ARS, with HMT for 16 hours at 80 °C and CAT with 0.6 M citric acid, resulting in the most pronounced effects. These changes coincided with reductions in rapidly digestible starch (RDS) levels and improvements in the ratio of slowly digestible starch (SDS) to RDS, which could potentially improve glycemic control. This study also examined the impact of processed ARS on colonic microbiota composition. It found that ARS-derived RS formed under HMT and CAT did not negatively affect the prebiotic potential of the RS fraction. Both treatments were associated with lowering the Firmicutes to Bacteroidetes ratio (F/B), a marker of gut health, and decreasing the relative abundance of Proteobacteria, microbes associated with adverse health effects. Additionally, CAT-derived RS showed a significant increase in the relative abundance of Roseburia, a beneficial gut bacterium. In conclusion, processing ARS through HMT and CAT techniques has the potential for enhancing its RS content, improving its glycemic impact, and positively influencing the gut microbiota composition, potentially contributing to gut health and metabolic well-being.

A multihole nozzle controls recrystallization of high-moisture extruded maize starches: Effect of cooling die temperature

Hot extrusion is utilized for starch modification due to its high mechanical input and product output. Amylose recrystallization commences and primarily depends on intermolecular interactions after conventional extrusion. Hence, the design of a new component based on the existed extrusion system was aimed at facilitating molecular aggregation, potentially accelerating starch recrystallization. In this study, a nozzle sheet comprising 89 holes was integrated into the cooling die. The impact of the multihole nozzle on the structure and in vitro digestibility of extruded maize starches after retrogradation was examined at varying cooling die temperatures. The results showed that the nozzle-assembled extrusion system operated effectively without additional mechanical or yield losses. At 50 °C, the crystallinity of nozzle-produced starch was approximately 70 % higher than that of conventionally extruded starch, predominantly owing to the B-type allomorph of the amylose double helix. Recrystallized amylopectin was also found in these nozzle-produced starches, indicating that multihole nozzle-induced uniaxial elongational flow resulted in the rapid starch crystallization. The increased formation of recrystallized amylose led to improved molecular order in starch structures while reducing their digestibility. These findings revealed a new approach to improve starch crystallinity by incorporating a nozzle sheet in the extrusion process.

Improved accelerated stability of starch-chia oil fatty acid inclusion complexes formed under mild reaction conditions

The starch inclusion complexation of sensitive compounds requires the use of conditions that minimize their degradation. This research work is aimed at investigating the effect of an alkaline complexation method employing mild reaction conditions on the physicochemical properties and accelerated stability of inclusion complexes of high amylose corn starch with omega-3 and omega-6 fatty acids. Hydrolyzed chia seed oil, rich in α-linolenic and linoleic fatty acids, was used as guest material and was incorporated at two ratios (10 and 20 % w/w hydrolysate/starch). Under the reaction conditions assessed, it were successfully formed V-type inclusion complexes with a high content of omega-3 and omega-6 (3.9-6 %). The initial hydrolysate concentration did not have a significant effect on the structural (crystallinity, short-range order) and thermal (dissociation temperature, melting enthalpy) properties. The method studied allowed the formation of complexes with an enhanced accelerated oxidative stability, compared to those formed using thermal treatment. The complexes formed using mild conditions with 20 % hydrolysate content had the highest oxidative stability, showing an omega-3 and omega-6 retention >90 % after 6 h of storage at 90 °C, an enhanced stability under thermogravimetric analysis, and flattened Rancimat curves, suggesting an appropriate preliminary behavior as potential carriers of bioactive fatty acids.

Advancements in enhancing resistant starch type 3 (RS3) content in starchy food and its impact on gut microbiota: A review

Resistant starch type 3 (RS3), often found in cooked starchy food, has various health benefits due to its indigestible properties and physiological functions such as promoting the abundance of gut beneficial microbial flora and inhibiting the growth of intestinal pathogenic bacteria. However, it is challenging to develop starchy food with high RS3 content. This review aims to provide a detailed overview of current advancements to enhance RS3 content in starchy food and its effects of RS3 on gut microbiota. These approaches include breeding high-amylose cereals through gene editing techniques, processing, enzyme treatments, storage, formation of RS3 nanoparticles, and the incorporation of bioactive compounds. The mechanisms, specific conditions, advantages, and disadvantages associated with each approach and the potential effects of RS3 prepared by different methods on gut microbiota are summarized. In conclusion, this review contains important information that aims to provide guidelines for developing an efficient RS3 preparation process and promote the consumption of RS3-enriched starchy foods to improve overall health outcomes.

V-type granular starches prepared by maize starches with different amylose contents: An investigation in structure, physicochemical properties and digestibility

V-type granular starches (VGSs) were prepared via an ethanol-alkaline (EA) method using maize starch with different amylose contents, specifically, high amylose (HAM), normal maize starch (MS), and waxy maize starch (WS). The X-ray diffraction pattern of the native starch was completely transformed into a V-type pattern after the EA treatment, indicating a structural change in the starch granules. The VGSs prepared by HAM had highest relative crystallinity (31.8°), while the VGSs prepared by WS showed amorphous diffraction pattern. Excessive NaOH, however, would disrupt the formation of V-type structures and cause granular shape rupture. The quantity of double-helical structures, particularly those formed by amylopectin at the starch granules' periphery, significantly decreased. Conversely, single-helical structures formed by amylose increased. A notable rise in the relative crystallinity of V crystals. Four VGS samples, characterized by granular integrity, were chosen for the next investigation of physicochemical and digestive properties. VGS prepared from HAM exhibited higher granular integrity, lower cold-water swelling extent (59.0 and 161.0 cP), improved thermal stability (the value of breakdown as lower as 57.67 and 186.67 cP), and higher resistance to digestion (RS content was up to 10.38 % and 9.00 % higher than 5.86 % and 5.66 % of VGS prepared from WS and MS). The results confirmed that amylose content has a substantial impact on the microstructural and physicochemical properties of VGSs.

Structural and functional insights of starch processing α-amylase from hyperthermophilic archaeon Pyrococcusabyssi

The genomic screening of hyper-thermophilic Pyrococcus abyssi showed uncharacterized novel α-amylase sequences. Homology modelling analysis revealed that the α-amylase from P. abyssi consists of an N-terminal GH57 catalytic domain, α-amylase central, and C-terminal domain. Current studies emphasize in-silico structural and functional analysis, recombinant expression, characterization, structural studies through CD spectroscopy, and ligand binding studies of the novel α-amylase from P. abyssi. The soluble expression of PaAFG was observed in the E. coli Rosetta™ (DE3) pLysS strain upon incubation overnight at 18 °C in an orbital shaker. The optimum temperature and pH of the PaAFG were observed at 90 °C in 50 mM phosphate buffer pH 6. The Km value for PaAFG against wheat starch was determined as 0.20 ± 0.053 mg while the corresponding Vmax value was 25.00 ± 0.67 μmol min-1 mg-1 in the presence of 2 mM CaCl2 and 12.5 % glycerol. The temperature ramping experiments through CD spectroscopy reveal no significant change in the secondary structures and positive and negative ellipticities of the CD spectra showing the proper folding and optimal temperature of PaAFG protein. The RMSD and RMSF of the PaAFG enzyme determined through molecular dynamic simulation show the significant protein's stability and mobility. The soluble production, thermostability and broad substrate specificity make this enzyme a promising choice for various industrial applications.

Investigating the effect of SUMO fusion on solubility and stability of amylase-catalytic domain from Pyrococcus abyssi

Alpha amylase belonging to starch hydrolyzing enzymes has significant contributions to different industrial processes. The enzyme production through recombinant DNA technology faces certain challenges related to their expression, solubility and purification, which can be overcome through fusion tags. This study explored the influence of SUMO, a protein tag reported to enhance the solubility and stability of target proteins when fused to the N-terminal of the catalytic domain of amylase from Pyrococcus abyssi (PaAD). The insoluble expression of PaAD in E. coli was overcome when the enzyme was expressed in a fusion state (S-PaAD) and culture was cultivated at 18 °C. Moreover, the activity of S-PaAD increased by 1.5-fold as compared to that of PaAD. The ligand binding and enzyme activity assays against different substrates demonstrated that it was more active against 1 % glycogen and amylopectin. The analysis of the hydrolysates through HPLC demonstrated that the enzyme activity is mainly amylolytic, producing longer oligosaccharides as the major end product. The secondary structure analyses by temperature ramping in CD spectroscopy and MD simulation demonstrated the enzymes in the free, as well as fusion state, were stable at 90 °C. The soluble production, thermostability and broad substrate specificity make this enzyme a promising choice for various foods, feed, textiles, detergents, pharmaceuticals, and many industrial applications.

Feasibility of replacing waxy rice with waxy or sweet-waxy corn viewed from the structure and physicochemical properties of starches

To explore the feasibility of substituting waxy rice with waxy or sweet-waxy corn, eight varieties of waxy and sweet-waxy corns were selected, including three self-cultivated varieties (Feng nuo 168, Feng nuo 211, and Feng nuo 10). Their starches were isolated and used as research objects, and commercially available waxy rice starch (CAWR) and waxy corn starch (CAWC) were used as controls. X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, rapid viscosity analyzer, and rotational rheometer were used to analyze their physicochemical and structural characteristics. The morphologies of all corn starch granules were generally oval or round, with significant differences in particle size distributions. All ten starches exhibited a typical A-type crystal structure; however, their relative crystallinity varied from 20.08% to 31.43%. Chain length distribution analysis showed that the A/B ratio of Jing cai tian nuo 18 and Feng nuo 168 was similar to that of CAWR. Peak viscosities of corn starches were higher than that of CAWR, except for Feng nuo 10, while their setback values were lower than that of CAWR. Except for Feng nuo 10, the paste transparency of corn starches was higher than that of CAWR (10.77%), especially for Jing cai tian nuo 18 (up to 24%). In summary, Jing cai tian nuo 18 and Feng nuo 168 are promising candidates to replace CAWR in developing various rice-based products.

Understanding resistant-starch formation during drying high-amylose maize kernels

Interests in using high-amylose maize (HAM) flour and starch for low glycemic index foods continue to grow. The objective of this work was to understand resistant-starch formation during drying the HAM kernels. Freshly harvested HAM kernels with 28.2 % initial moisture were subjected to sun drying (~30 °C) or hot-air drying at 50 °C, 70 °C, 90 °C, or 110 °C. The enzymatic digestibility of HAM flour decreased from 63.6 % to 41.1 % as the drying temperature increased from 30 °C to 110 °C. The swelling power, solubility, and overall viscosity of HAM flours milled from kernels dried at 110 °C decreased, whereas the peak and conclusion gelatinization temperatures, enthalpy change, and relative crystallinity increased compared to those of flours from kernels dried at 30 °C, 50 °C, 70 °C, and 90 °C. Light microscopic and scanning electron microscopic images showed that starch granule aggregation in HAM flour increased with increasing drying-temperatures. The aggregates remained after 16 h enzymatic hydrolysis of cooked HAM flours. These results suggested that the increase of enzymatic resistance of HAM flour resulted from the formation of high temperature-resistant ordered structures in starch granules and the starch aggregates less accessible to enzymatic hydrolysis.

Stimuli responsiveness of recent biomacromolecular systems (concept to market): A review

Stimuli responsive delivery systems, also known as smart/intelligent drug delivery systems, are specialized delivery vehicles designed to provide spatiotemporal control over drug release at target sites in various diseased conditions, including tumor, inflammation and many others. Recent advances in the design and development of a wide variety of stimuli-responsive (pH, redox, enzyme, temperature) materials have resulted in their widespread use in drug delivery and tissue engineering. The aim of this review is to provide an insight of recent nanoparticulate drug delivery systems including polymeric nanoparticles, dendrimers, lipid-based nanoparticles and the design of new polymer-drug conjugates (PDCs), with a major emphasis on natural along with synthetic commercial polymers used in their construction. Special focus has been placed on stimuli-responsive polymeric materials, their preparation methods, and the design of novel single and multiple stimuli-responsive materials that can provide controlled drug release in response a specific stimulus. These stimuli-sensitive drug nanoparticulate systems have exhibited varying degrees of substitution with enhanced in vitro/in vivo release. However, in an attempt to further increase drug release, new dual and multi-stimuli based natural polymeric nanocarriers have been investigated which respond to a mixture of two or more signals and are awaiting clinical trials. The translation of biopolymeric directed stimuli-sensitive drug delivery systems in clinic demands a thorough knowledge of its mechanism and drug release pattern in order to produce affordable and patient friendly products.

Preparation of starch-palmitic acid complexes by three different starches: A comparative study using the method of heating treatment and autoclaving treatment

Recent research emphasizes the growing importance of starch-lipid complexes due to their anti-digestibility ability, prompting a need to explore the impact of different starch sources and preparation methods on their properties. In this study, starch-palmitic acid (PA) complexes were prepared by three different starches including Tartary buckwheat starch (TBS), potato starch (PTS), and pea starch (PS) by heating treatment (HT) and autoclaving treatment (AT), respectively, and their physicochemical property and in vitro digestibility were systematically compared. The formation of the starch-PA complex was confirmed through various characterization techniques, including scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction. Among the complexes, the PTS-PA complex exhibited the highest complexation index over 80 %, while the PS-PA complex had the lowest rapid digestible starch content (56.49-59.42 %). Additionally, the complexes prepared by AT exhibited higher resistant starch content (41.95-32.46 %) than those prepared by HT (31.42-32.49 %), while the complexes prepared by HT held better freeze-thaw stability and hydration ability than those prepared by AT. This study highlights the important role of starch sources in the physicochemical and digestibility properties of starch-lipid complex and the potential application of AT in the preparation of novel resistant starch.

Unraveling the gut health puzzle: exploring the mechanisms of butyrate and the potential of High-Amylose Maize Starch Butyrate (HAMSB) in alleviating colorectal disturbances

Colorectal disturbances encompass a variety of disorders that impact the colon and rectum, such as colitis and colon cancer. Butyrate, a short-chain fatty acid, plays a pivotal role in supporting gut health by nourishing colonocytes, promoting barrier function, modulating inflammation, and fostering a balanced microbiome. Increasing colorectal butyrate concentration may serve as a critical strategy to improve colon function and reduce the risk of colorectal disturbances. Butyrylated high-amylose maize starch (HAMSB) is an edible ingredient that efficiently delivers butyrate to the colon. HAMSB is developed by esterifying a high-amylose starch backbone with butyric anhydride. With a degree of substitution of 0.25, each hydroxy group of HAMSB is substituted by a butyryl group in every four D-glucopyranosyl units. In humans, the digestibility of HAMSB is 68% (w/w), and 60% butyrate molecules attached to the starch backbone is absorbed by the colon. One clinical trial yielded two publications, which showed that HAMSB significantly reduced rectal O6-methyl-guanine adducts and epithelial proliferation induced by the high protein diet. Fecal microbial profiles were assessed in three clinical trials, showing that HAMSB supplementation was consistently linked to increased abundance of Parabacteroides distasonis. In animal studies, HAMSB was effective in reducing the risk of diet- or AOM-induced colon cancer by reducing genetic damage, but the mechanisms differed. HAMSB functioned through affecting cecal ammonia levels by modulating colon pH in diet-induced cancer, while it ameliorated chemical-induced colon cancer through downregulating miR19b and miR92a expressions and subsequently activating the caspase-dependent apoptosis. Furthermore, animal studies showed that HAMSB improved colitis via regulating the gut immune modulation by inhibiting histone deacetylase and activating G protein-coupled receptors, but its role in bacteria-induced colon colitis requires further investigation. In conclusion, HAMSB is a food ingredient that may deliver butyrate to the colon to support colon health. Further clinical trials are warranted to validate earlier findings and determine the minimum effective dose of HAMSB.

Molecular rotor as an in-situ fluorescent probe for the degree of polymerization of α-D-1,4-glucans

Various starch synthesis and tailoring processes involve prevailing adjustments in the degree of polymerization (DP) of linear α-D-1,4-glucan chains (LGCs) for the improved functional performances. Previous studies indicated that LGCs might hinder the twisted relaxation of 9-(2-carboxy-2-cyanovinyl)-julolidine (CCVJ, a hydrophilic molecular rotor), highlighting CCVJ as a potential in-situ structural probe for LGC. In this study, glucose and its α-D-1,4 oligomers and polymers with molecular weights ranging from 0.18 kDa to 70.00 kDa were prepared as the model molecules (MM). The fluorescent emission behavior of CCVJ in various concentrations (1-5 g/L) of MM solutions or dispersions were analyzed. Results showed that for the low-DP MMs (≤ 3.98 kDa) with good aqueous stability, CCVJ emission increased by about 20 times with the DP of MMs. In contrast, CCVJ generally emitted weak DP-relevant but glucan content-dependent fluorescence in response to the interaction with high-DP MMs (> 3.98 kDa). Furthermore, a double-logarithmic linear relationship was found between the emission intensity of CCVJ and the molar-based molecular weight of glucan. The result combined with the molecular dynamic simulation suggested that CCVJ underwent surface-to-surface interaction with MMs. This study may contribute to the real-time analysis of the DP of α-D-1,4 oligoglucosides in maltodextrin and starch syrup.

Development of a Novel Energy Saving and Environmentally Friendly Starch via a Graft Copolymerization Strategy for Efficient Warp Sizing and Easy Removal

Warp sizing is a key process in textile production. However, before the yarn/fabric finishing, such as dyeing, the paste adhering to the warp must be eliminated to ensure optimal dyeing properties and the flexibility of the fabric. Therefore, the sizing will often consume a lot of energy and produce a lot of industrial wastewater, which will cause serious harm to the environment. In this study, we have developed an energy saving and environmentally friendly starch-based slurry by modifying natural starch with acrylamide. The paste has excellent viscosity stability and fiber adhesion, and exhibits excellent performance during warp sizing. In addition, the slurry has good water solubility at 60-70 °C, so it is easy to desize at low temperatures. Because of this, the sizing of the warp can be deslimed directly from the yarn during subsequent washing processes. This work can not only reduce some costs for the textile industry, but also achieve the purpose of energy conservation and emission reduction.

Effect of structural characteristics of resistant starch prepared by various methods on microbial community and fermentative products

Resistant starch (RS) has been extensively studied because of its beneficial effects on gut microbiota. In this study, four RSs obtained through various preparation processes were utilized for in vitro fermentation, and their structural characteristics before and after fermentation were determined using chromatography, Fourier infrared spectroscopy, and scanning electron microscopy (SEM). It was observed that these RSs can be classified into two categories based on their fermentation and structural features. The autoclaving RS (ARS) and extruding RS (ERS) were classified as Class I Microbiome Community (MC-I), characterized by a higher proportion of butyrate and its producers, including unclassified_g_Megasphaera and Megasphaera elsdenii. While microwaving RS (MRS) and ultrasound RS (URS) belonged to Class II Microbiome Community (MC-II), marked by a higher proportion of acetate and its producer, Bifidobacterium pseudocatenulatum DSM 20438. MC-I had a lower molecular weight, shorter chain length, more chains with degree of polymerization (DP) 36-100, and a more ordered structure than MC-II. Furthermore, SEM observations revealed distinct degradation patterns between MC-I and MC-II, which may be attributed to their surface structural characteristics. These findings imply that the preparation methods employed for RS can determine its multilevel structural characteristics, and consequently influence its physiological properties.

Extrusion as pretreatment for complexation of high-amylose starch with glycerin monostearin: Dependence on the guest molecule

Low-moisture extrusion (LME) can modify starch structures and enrich their functionality. These LME-made starches may efficiently form inclusion complexes (ICs) with hydrophobic guest molecules, which is profoundly impacted by the guest molecule concentration. In this work, the influence of glycerin monostearin (GMS) concentration on the structure and in vitro digestibility of pre-extruded starch-GMS complexes was investigated. The results showed that LME pretreatment increased the complex index of high-amylose starch with GMS by 13 %. The appropriate GMS concentrations produced ICs with high crystallinity and excellent thermostability. The presence of IC retarded amylose retrogradation and dominated bound water in starches. In addition, highly crystallized ICs were resistant to enzymolysis and had a higher proportion of resistant starch. The acquired knowledge would provide a better understanding of the LME-modified starch and GMS concentration-regulated IC formation.

Pre-gelatinized high-amylose starch enables easy preparation of flexible and antimicrobial composite films for fresh fruit preservation

While high-amylose starch (HAS) possesses advantageous properties such as high resistant starch content and favorable mechanical attributes, its gelatinization constraints have limited its applicability. This study enhances its versatility by focusing on pre-gelatinized (PG) HAS with exceptional rehydratability, achieved by disorganizing native HAS granules (with amylose contents of 55 % and 68 %, respectively) using a 33 % CaCl2 solution, followed by water-ethanol precipitation and freeze-drying. The resulting PG-HAS exhibited elevated amylose content (61 % and 75 %) with minimal changes in amylose molecular weight. PG-HAS displayed superior water-absorption index (WAI) and water-soluble index (WSI) compared to native HAS, further improved by 2 % CaCl2 solution incorporation. Furthermore, composite films were prepared by mixing PG-HAS with PVA at a 6:4 (w/w) ratio. The PG-G50 (61 % amylose content)/PVA composite film exhibited remarkable elongation (131.1 ± 5.4 %), nearly three times that of a normal corn starch (NCS, with 27 % amylose)/PVA film, attributed to improved starch dispersity and higher amylose content. Nonetheless, the PG-G70 (75 % amylose content)/PVA film at the same ratio showed lower elongation (54.7 ± 8.0 %), potentially due to strong cohesive forces between amylose chains that impede starch-PVA interactions. Moreover, the PG-HAS/PVA composite films, enriched with antibacterial agents, demonstrated effective antibacterial properties with a gradual and sustained release of active compounds. Notably, the PG-G50/PVA/tannic acid (TA) film effectively preserved fresh apple slices by inhibiting bacteria growth and preventing browning. These findings underscore the excellent rehydration of PG-HAS and its potential as an inner packaging material for irregularly shaped foods, such as sliced fruits or meats, due to its nontoxic nature, softness and flexibility, which allows the film to maintain close contact with food surfaces.

Characteristics of physicochemical properties, structure and in vitro digestibility of seed starches from five loquat cultivars

Starch plays a pivotal role in food and other industries, necessitating the exploration of new starch sources to cater the substantial requirement. This study delved into the variations in the physicochemical properties, structure attributes and in vitro digestibility of seed starches extracted from five distinct loquat cultivars (Eriobotrya japonica L.). The starch extraction yield of loquat seeds was found to be 45.2 % as an average. Loquat seed starches were designated as having high-amylose starch (>50 %). The starch granules exhibited similar shapes, but granular size significantly varied across the cultivars. Loquat starches presented a C-type crystalline pattern with relative crystallinity from 17.14 % to 21.06 %. The short-range ordered structure of the starches differed with loquat cultivars. The swelling power, solubility and amylose leaching of loquat starches increased with increasing temperature, significantly varying among different cultivars. Gelatinization parameters exhibited significant variations among the loquat starches. Different loquat starches exhibited pronounced variations in paste clarity, water and oil absorption capacity. Marked differences were detected in proportions of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) across the five cultivars, with RS being particularly prominent fraction with an average of 84.30 %. These compressive findings offer valuable insights into the potential application of loquat seed starches in the formulation of foods and various industrial products.

Glucan, water dikinase (GWD) penetrates the starch granule surface and introduces C6 phosphate in the vicinity of branching points

Starch phosphorylation mediated by α-glucan, water dikinase is an integral part of starch metabolism. So far however, it is not fully understood. For getting deeper insights, several in vitro assays and intensive mass spectrometry analyses were performed. Such analyses allowed us to determine the phosphorylation position within the amylopectin in detail. Thus, unique features of the starch structure and GWD action were correlated. Therefore, recombinant potato GWD (Solanum tuberosum L.; StGWD) was used for detailed analyses of the phosphorylation pattern of various starches. Additionally, oil palm (Elaeis guineensis Jacq.; EgGWD) GWD was cloned and characterized, representing the first characterization of GWD of a monocot species. The distribution patterns of single phosphorylated glucan chains catalyzed by both GWDs were compared. The phosphorylation distribution patterns of both GWDs varied for different starches. It was proven that GWD phosphorylates different positions within the amylopectin of native starch granules. GWD enters the starch granule surface and phosphorylates the glucosyl units in the proximity of branching points to convert the highly ordered glucan chains into a less ordered state and to render them accessible for the downstream acting hydrolases. This enables deciphering the GWD actions and the related structural properties of starch granules.

A review of starch swelling behavior: Its mechanism, determination methods, influencing factors, and influence on food quality

Swelling behavior involves the process of starch granules absorbing enough water to swell and increase the viscosity of starch suspension under hydrothermal conditions, making it one of the important aspects in starch research. The changes that starch granules undergo during the swelling process are important factors in predicting their functional properties in food processing. However, the factors that affect starch swelling and how swelling, in turn, affects the texture and digestion characteristics of starch-based foods have not been systematically summarized. Compared to its long chains, the short chains of amylose easily interact with amylopectin chains to inhibit starch swelling. Generally, reducing the swelling of starch could increase the strength of the gel while limiting the accessibility of digestive enzymes to starch chains, resulting in a reduction in starch digestibility. This article aims to conduct a comprehensive review of the mechanism of starch swelling, its influencing factors, and the relationship between swelling and the pasting, gelling, and digestion characteristics of starch. The role of starch swelling in the edible quality and nutritional characteristics of starch-based foods is also discussed, and future research directions for starch swelling are proposed.

A critical review on biodegradable food packaging for meat: Materials, sustainability, regulations, and perspectives in the EU

The development of biodegradable packaging is a challenge, as conventional plastics have many advantages in terms of high flexibility, transparency, low cost, strong mechanical characteristics, and high resistance to heat compared with most biodegradable plastics. The quality of biodegradable materials and the research needed for their improvement for meat packaging were critically evaluated in this study. In terms of sustainability, biodegradable packagings are more sustainable than conventional plastics; however, most of them contain unsustainable chemical additives. Cellulose showed a high potential for meat preservation due to high moisture control. Polyhydroxyalkanoates and polylactic acid (PLA) are renewable materials that have been recently introduced to the market, but their application in meat products is still limited. To be classified as an edible film, the mechanical properties and acceptable control over gas and moisture exchange need to be improved. PLA and cellulose-based films possess the advantage of protection against oxygen and water permeation; however, the addition of functional substances plays an important role in their effects on the foods. Furthermore, the use of packaging materials is increasing due to consumer demand for natural high-quality food packaging that serves functions such as extended shelf-life and contamination protection. To support the importance moving toward biodegradable packaging for meat, this review presented novel perspectives regarding ecological impacts, commercial status, and consumer perspectives. Those aspects are then evaluated with the specific consideration of regulations and perspective in the European Union (EU) for employing renewable and ecological meat packaging materials. This review also helps to highlight the situation regarding biodegradable food packaging for meat in the EU specifically.

The antioxidant activity of polysaccharides: A structure-function relationship overview

Over the last years, polysaccharides have been linked to antioxidant effects using both in vitro chemical and biological models. The reported structures, claimed to act as antioxidants, comprise chitosan, pectic polysaccharides, glucans, mannoproteins, alginates, fucoidans, and many others of all type of biological sources. The structural features linked to the antioxidant action include the polysaccharide charge, molecular weight, and the occurrence of non-carbohydrate substituents. The establishment of structure/function relationships can be, however, biased by secondary phenomena that tailor polysaccharides behavior in antioxidant systems. In this sense, this review confronts some basic concepts of polysaccharides chemistry with the current claim of carbohydrates as antioxidants. It critically discusses how the fine structure and properties of polysaccharides can define polysaccharides as antioxidants. Polysaccharides antioxidant action is highly dependent on their solubility, sugar ring structure, molecular weight, occurrence of positive or negatively charged groups, protein moieties and covalently linked phenolic compounds. However, the occurrence of phenolic compounds and protein as contaminants leads to misleading results in methodologies often used for screening and characterization purposes, as well as in vivo models. Despite falling in the concept of antioxidants, the role of polysaccharides must be well defined according with the matrices where they are involved.

Starch-Based Polymer Materials as Advanced Adsorbents for Sustainable Water Treatment: Current Status, Challenges, and Future Perspectives

Over the past three decades, chemical and biological water contamination has become a major concern, particularly in the industrialized world. Heavy metals, aromatic compounds, and dyes are among the harmful substances that contribute to water pollution, which jeopardies the human health. For this reason, it is of the utmost importance to locate methods for the cleanup of wastewater that are not genuinely effective. Owing to its non-toxicity, biodegradability, and biocompatibility, starch is a naturally occurring polysaccharide that scientists are looking into as a possible environmentally friendly material for sustainable water remediation. Starch could exhibit significant adsorption capabilities towards pollutants with the substitution of amide, amino, carboxyl, and other functional groups for hydroxyl groups. Starch derivatives may effectively remove contaminants such as oil, organic solvents, pesticides, heavy metals, dyes, and pharmaceutical pollutants by employing adsorption techniques at a rate greater than 90%. The maximal adsorption capacities of starch-based adsorbents for oil and organic solvents, pesticides, heavy metal ions, dyes, and pharmaceuticals are 13,000, 66, 2000, 25,000, and 782 mg/g, respectively. Although starch-based adsorbents have demonstrated a promising future for environmental wastewater treatment, additional research is required to optimize the technique before the starch-based adsorbent can be used in large-scale in situ wastewater treatment.

Functional properties and in vitro starch digestibility of infrared-treated (micronized) green banana flour

BACKGROUND

The consumption of green banana flour (GBF) products has been linked to reduced glycemic index (GI) and low risk of type 2 diabetes and obesity. The purpose of this study was to investigate the effect of micronization (high-intensity infrared heating method) on the molecular, microstructure and in vitro starch digestibility of five GBF cultivars grown in South Africa. The GBF was micronized at three surface temperatures (90, 120 and 150 °C for 30 min) and the in vitro starch digestibility was determined with Megazyme kits.

RESULTS

Micronization at the highest temperature (150 °C) increased the swelling power by 6.00% in all five GBF cultivars when compared to control (unmicronized GBF). Micronization slightly reduced the resistant starch (RS) of the GBF cultivars by up to 8.63%. The FHIA-01 cultivar showed the highest RS (86.50%), whereas Grande Naine - 150 °C cultivar had the lowest RS (76.00%). Both micronized and control GBF exhibited similar X-ray diffraction patterns with all cultivars and at all micronization temperatures. Similarly, the functional properties of the GBF were not altered by micronization when observed with Fourier transform infrared spectroscopy. Scanning electron microscopy showed changes in the surface morphology of starch granules after micronization and these were dependent on temperature.

CONCLUSION

Overall, micronization at 120 °C showed the best improvement in functional properties of GBF and this makes it suitable for potential application for the manufacture of instant breakfast products, baked goods and pasta. In addition, the micronized GBF cultivars retained high RS, suggesting potential health benefits for people with diabetes and obesity. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Native and modified starches from underutilized seeds: Characteristics, functional properties and potential applications

Seeds represent a potential source of starch, containing at least 60-70% of total starch, however many of them are treated as waste and are usually discarded. The review aim was to analyze the characteristics, functional properties, and potential applications of native and modified starches from underutilized seeds such as Sorghum bicolor L. Moench (WSS), Chenopodium quinoa, Wild. (QSS), Mangifera indica L. (MSS), Persea americana Mill. (ASS), Pouteria campechiana (Kunth) Baehni (PCSS), and Brosimum alicastrum Sw. (RSS). A systematic review of scientific literature was carried out from 2014 to date. Starch from seeds had yields above 30%. ASS had the higher amylose content and ASS and RSS showed the highest values in water absorption capacity and swelling power, contrary to MSS and PCSS while higher thermal resistance, paste stability, and a lower tendency to retrograde were observed in MSS and RSS. Functional properties such as water solubility, swelling power, thermal stability, low retrogradation tendency, and emulsion stability were increased in RSS, WSS, QSS, and MSS with chemical modifications (Oxidation, Oxidation-Crosslinking, OSA, DDSA, and NSA) and physical methods (HMT and dry-heat). Digestibility in vitro showed that WSS and QSS presented high SDS fraction, while ASS, MSS, PCSS, and HMT-QSS presented the highest RS content. Native or modified underutilized seed starches represent an alternative and sustainable source of non-conventional starch with potential applications in the food industry and for the development of healthy foods or for special nutritional requirements.

The physicochemical properties and Pickering emulsifying capacity of acorn starch

In this work, the granule characteristics, functional properties, in-vitro digestibility, antioxidant capacity, and phenolic composition of acorn starch were investigated and compared to those of potato starch and corn starch, and its Pickering emulsifying ability was also evaluated. The results showed that the acorn starch granules were spherical and oval in shape, with a smaller particle size, and the amylose content and crystallinity degree were similar to those of corn starch. However, the acorn starch was difficult to swell, with poor aqueous solubility, though it had a strong gel strength and setback viscosity. Because acorn starch contained more free and bound polyphenols, its resistant starch content after cooking and ABTS and DPPH radical scavenging activities were significantly higher than those of potato starch and corn starch. Acorn starch also exhibited outstanding particle wettability and could stabilize Pickering emulsions. The assessed emulsion showed an outstanding effect for protecting β-carotene against ultraviolet irradiation and was positively correlated with the acorn starch addition amount. The obtained results may serve as a reference for the further development of acorn starch.

Effect of Dry Heating on Some Physicochemical Properties of Protein-Coated High Amylose and Waxy Corn Starch

The dry heat treatment (DHT) of starch and hydrocolloid mixtures is gaining acknowledgement since hydrocolloids can enhance the efficiency of DHT. However, the DHT of a starch-protein mixture has been less investigated. In this study, the effects of different proteins including sodium caseinate (SC), gelatin, and whey protein isolate (WPI) added to high amylose and waxy corn starches (HACS and WCS, respectively) prepared by the dry mixing and wet method before and after DHT were studied. The DHT of both starches with WPI and SC prepared by the wet method increased the peak viscosity, but no change was observed when gelatin was added. Dry mixing of HACS with the proteins did not affect the peak viscosity before and after DHT. The gelatinization temperatures and enthalpy of both starches showed a slight decrease with the addition of all proteins and reduced further after DHT. The firmness, gumminess, and cohesiveness of the samples decreased upon DHT. The SEM results revealed that the granules were coated by proteins and formed clusters. Particle size analysis showed an increase in the particle size with the addition of proteins, which reduced after DHT. Under the conditions used, the wet method was more successful than dry mixing and the effects of WPI > SC > gelatin in enhancing the physicochemical properties of the tested starches after DHT.