Structure-function relationships of starch components

Effects of Aspergillus flavus infection on multi-scale structures and physicochemical properties of maize starch during storage

This study systematically analyzed the effect of Aspergillus flavus infection on the maize starch multi-scale structure, physicochemical properties, processing characteristics, and synthesis regulation. A. flavus infection led to a decrease in the content of starch, an increase in the content of reactive oxygen species (ROS) and malondialdehyde (MDA), a significant decrease in the activities of peroxidase (POD) and superoxide dismutase (SOD). In addition, A. flavus infection had a significant destructive effect on the double helix structure, relative crystallinity and lamellar structure of starch, resulting in the reduction of starch viscosity, affecting the viscoelastic properties of starch, and complicating the gel formation process. However, the eugenol treatment group significantly inhibited the growth of A. flavus during maize storage, protecting the multi-scale structure and processing characteristics of maize starch from being damaged. Transcriptome analysis showed that genes involved in carbohydrate synthesis in maize were significantly downregulated and genes involved in energy synthesis were significantly upregulated, indicating that maize converted its energy storage into energy synthesis to fight the invasion of A. flavus. These results of this study enriched the mechanism of quality deterioration during maize storage, and provide theoretical and technical support for the prevention of A. flavus infection during maize storage.

A review of the effects of physical processing techniques on the characteristics of legume starches and their application in low-glycemic index foods

Physical processing techniques significantly influence the characteristics of legume starch, consequently affecting the potential applications of legume-based products. This review comprehensively examines the impact of various physical processing techniques on legume starch properties, including structure, granule morphology, gelatinization, pasting properties, solubility, and in vitro digestibility. Furthermore, it evaluates the implications of these processing methods for utilizing legumes in developing low-glycemic index (GI) foods. Notably, certain physical processing methods, such as heat-moisture treatment, ultrahigh-pressure processing, dry heat treatment, and gamma irradiation, under specific conditions, enhance the resistant starch or slowly digestible starch fractions in legume starches. This enhancement is particularly advantageous for producing low-GI foods. Conversely, techniques like annealing, extrusion, ultrasound, and germination increase starch digestibility, which is less favorable for low-GI food applications. This review also provides an up-to-date overview of the use of diverse preprocessed legume products in low-GI food production. The novelty of this review lies in its detailed comparative analysis of physical processing methods and their specific effects on legume starch digestibility, which has not been extensively covered in existing literature. The comprehensive insights presented herein will benefit the legume industry by informing effective strategies for converting legume starch into valuable low-GI products.

The Effect of Maltose on Structural, Physicochemical, and Digestive Properties of Lentil Starch under Electron Beam Irradiation

This study investigated the effects of electron beam irradiation (EBI) on the structural, physicochemical, and functional properties of lentil starch with varying maltose content. EBI did not significantly disrupt the starch's surface structure or cause amorphization of starch and maltose crystals, but it significantly reduced the intensity of starch's XRD peaks. The presence of maltose intensified internal growth ring damage, leading to more cross-link and rearrangement between short chains, improving short-range ordering of lentil starch and enhancing starch's solubility and thermal stability. Additionally, adding maltose that EBI then treats can lead to an increased content of slowly digestible starch in samples.

Effects of nitrogen fertilizer application on the physicochemical properties of foxtail millet (Setaria italica L.) starch

The use of nitrogen fertilizer is a crucial agronomic practice to increase crop output and quality. This study investigated the impact of five nitrogen application levels (0, 60, 135, 210, and 285 kg N/hm2) on the physicochemical properties of foxtail millet (FM) starch. Optimal nitrogen application (210 kg N/hm2) significantly increased L*, a*, and b* values, water and oil absorption capacity, water solubility, and swelling power of starch. The number of small starch granules increased as the nitrogen application rate increased, but the granule morphology and typical A-type pattern did not change among the treatments. Nitrogen application increased the relative crystallinity and ordered structure, resulting in a higher gelatinization enthalpy. Compared to the control group (7.02 J/g), the enthalpy increased by 21.94 %, 66.38 %, 73.50 %, and 103.28 % under the nitrogen application rates, respectively. Moreover, nitrogen application greatly increased the percentage of A and B3 chains while it lowered the apparent amylose content, peak viscosity, and final viscosity. The effects of 210 and 285 kg N/hm2 treatments on the water solubility and swelling power, water and oil absorption, and light transmission of starch were greater compared to the 60 and 135 kg N/hm2 treatments. These results indicate that nitrogen fertilization significantly affects the physicochemical properties of FM starch.

On the architecture of starch granules revealed by iodine vapor binding and lintnerization. Part 1: Microscopic examinations

Structural nature of glucan chains in the amorphous part of granular starch was examined by iodine vapor treatment and lintnerization. Four iodine-stained amylose-containing normal starches and their waxy counterparts were examined under a microscope before, during, and after lintnerization. The presence of amylose retarded the lintnerization rate. The degree of retardation correlated with the structural type of the amylopectin component, suggesting that potato amylopectin (type 4 structure) interacts with amylose in the granules, whereas in barley granules (type 1 structure) the interaction is very weak. The inclusion complexes with iodine were not degraded by the acid treatment. Therefore, the iodine-glucan chain complex formation could be used to study the structural nature of the flexible, amorphous parts of the starch granules. Indeed, at the end of lintnerization, when 20%-30% of the granules remained, substantial amounts of blue-stained complexes were washed out from the granules especially from amylose-containing barley and maize starch, but also from both normal and waxy cassava and potato starch. The complexation with iodine did not affect the rate of lintnerization. This suggested that single helical structures were present during lintnerization also in the absence of iodine and this conformation was the reason for the acid resistance.

Structural insights into α-(1→6)-linkage preference of GH97 glucodextranase from Flavobacterium johnsoniae

Glycoside hydrolase family 97 (GH97) comprises enzymes like anomer-inverting α-glucoside hydrolases (i.e., glucoamylase) and anomer-retaining α-galactosidases. In a soil bacterium, Flavobacterium johnsoniae, we previously identified a GH97 enzyme (FjGH97A) within the branched dextran utilization locus. It functions as an α-glucoside hydrolase, targeting α-(1→6)-glucosidic linkages in dextran and isomaltooligosaccharides (i.e., glucodextranase). FjGH97A exhibits a preference for α-(1→6)-glucoside linkages over α-(1→4)-linkages, while Bacteroides thetaiotaomicron glucoamylase SusB (with 69% sequence identity), which is involved in the starch utilization system, exhibits the highest specificity for α-(1→4)-glucosidic linkages. Here, we examined the crystal structures of FjGH97A in complexes with glucose, panose, or isomaltotriose, and analyzed the substrate preferences of its mutants to identify the amino acid residues that determine the substrate specificity for α-(1→4)- and α-(1→6)-glucosidic linkages. The overall structure of FjGH97A resembles other GH97 enzymes, with conserved catalytic residues similar to anomer-inverting GH97 enzymes. A comparison of active sites between FjGH97A and SusB revealed differences in amino acid residues at subsites +1 and +2 (specifically Ala195 and Ile378 in FjGH97A). Among the three mutants (A195S, I378F, and A195S-I378F), A195S and A195S-I378F exhibited increased activity toward α-(1→4)-glucoside bonds compared to α-(1→6)-glucoside bonds. This suggests that Ala195, located on the Gly184-Thr203 loop (named loop-N) conserved within the GH97 subgroup, including FjGH97A and SusB, holds significance in determining linkage specificity. The conservation of alanine in the active site of the GH97 enzymes, within the same gene cluster as the putative dextranase, indicates its crucial role in determining the specificity for α-(1→6)-glucoside linkage.

Insight to starch retrogradation through fine structure models: A review

The retrogradation of starch is crucial for the texture and nutritional value of starchy foods products. There is mounting evidence highlighting the significant impact of starch's fine structures on starch retrogradation. Because of the complexity of starch fine structure, it is a formidable challenge to study the structure-property relationship of starch retrogradation. Several models have been proposed over the years to facilitate understanding of starch structure. In this review, from the perspective of starch models, the intricate structure-property relationship is sorted into the correlation between different types of structural parameters and starch retrogradation performance. Amylopectin B chains with DP 24-36 and DP ≥36 exhibit a higher tendency to form ordered crystalline structures, which promotes starch retrogradation. The chains with DP 6-12 mainly inhibit starch retrogradation. Based on the building block backbone model, a longer inter-block chain length (IB-CL) enhances the realignment and reordering of starch. The mathematical parameterization model reveals a positive correlation between amylopectin medium chains, amylose short chains, and amylose long chains with starch retrogradation. The review is structured according to starch models; this contributes to a clear and comprehensive elucidation of the structure-property relationship, thereby providing valuable references for the selection and utilization of starch.

Characterization of Acid Hydrolyzed Taro Boloso-I (Colocasia esculenta Cultivar) Starch as a Diluent in Direct Compression of Tablets

Corn, wheat, rice, potato, and cassava starches have been widely used as pharmaceutical excipients. However, the search for cost-effective local starch alternatives is necessary due to the availability and usage constraints. In Ethiopia, various plant species, including Taro Boloso-I, have been explored as potential sources of pharmaceutical starch. It is a variety of Colocasia esculenta with a high tuber yield and high starch content. However, the native starch requires modifications to enhance its functionality. Therefore, this study aimed to improve the native starch through acid modification and evaluate its performance as a direct compressible tablet excipient. The native starch was treated with a 6% w/v HCl solution for 192 hours, resulting in acid-modified Taro Boloso-I starch, which was then evaluated for suitability for direct compression. XRD patterns of both the native and modified starch showed characteristic A-type crystals, with significantly higher relative crystallinity observed in the latter. Additionally, the acid-modified starch exhibited a lower moisture content and improved flow properties. The compaction study also demonstrated its improved compactibility (tensile strength: 16.82 kg/cm2), surpassing both the native starch (13.17) and Starch 1500® (11.2). The modified starch also showed a lower lubricant sensitivity compared to the native starch and Starch 1500®. Furthermore, paracetamol tablets made with the modified starch exhibited higher mechanical strength and lower friability in all paracetamol concentrations. It incorporated up to 40% paracetamol while maintaining acceptable tablet characteristics, whereas the native starch and Starch 1500® were limited to 30% (w/w). Based on these findings, the modified starch showed promise as an alternative direct compressible excipient in tablet manufacturing.

A Review of the Impact of Starch on the Quality of Wheat-Based Noodles and Pasta: From the View of Starch Structural and Functional Properties and Interaction with Gluten

Starch, as a primary component of wheat, plays a crucial role in determining the quality of noodles and pasta. A deep understanding of the impact of starch on the quality of noodles and pasta is fundamentally important for the industrial progression of these products. The starch structure exerts an influence on the quality of noodles and pasta by affecting its functional attributes and the interaction of starch-gluten proteins. The effects of starch structure (amylopectin structure, amylose content, granules size, damaged starch content) on the quality of noodles and pasta is discussed. The relationship between the functional properties of starch, particularly its swelling power and pasting properties, and the texture of noodles and pasta is discussed. It is important to note that the functional properties of starch can be modified during the processing of noodles and pasta, potentially impacting the quality of the end product, However, this aspect is often overlooked. Additionally, the interaction between starch and gluten is addressed in relation to its impact on the quality of noodles and pasta. Finally, the application of exogenous starch in improving the quality of noodles and pasta is highlighted.

Effect of dynamic high-pressure treatments on the multi-level structure of starch macromolecule and their techno-functional properties: A review

Over the past decades, dynamic high-pressure treatment (DHPT) executed by high-pressure homogenization (HPH) or microfluidization (DHPM) technology has received humongous research attention for starch macromolecule modification. However, the studies on starch multi-level structure alterations by DHPT have received inadequate attention. Furthermore, no review comprehensively covers all aspects of DHPT, explicitly addressing the combined effects of both technologies (HPH or DHPM) on starch's structural and functional characteristics. Hence, this review focused on recent advancements concerning the influences of DHPT on the starch multi-level structure and techno-functional properties. Intense mechanical actions induced by DHPT, such as high shear and impact forces, hydrodynamic cavitation, instantaneous pressure drops, and turbulence, altered the multi-level structure of starch for a short duration. The DHPT reduces the starch molecular weight and degree of branching, destroys short-range ordered and long-range crystalline structure, and degrades lamellar structure, resulting in partial gelatinization of starch granules. These structural changes influenced their techno-functional properties like swelling power and solubility, freeze-thaw stability, emulsifying properties, retrogradation rate, thermal properties, rheological and pasting, and digestibility. Processing conditions such as pressure level, the number of passes, inlet temperature, chamber geometry used, starch types, and their concentration may influence the above changes. Moreover, dynamic high-pressure treatment could form starch-fatty acids/polyphenol complexes. Finally, we discuss the food system applications of DHPT-treated starches and flours, and some limitations.

Improvement on wheat bread quality by in situ produced dextran-A comprehensive review from the viewpoint of starch and gluten

Deterioration of bread quality, characterized by the staling of bread crumb, the softening of bread crust and the loss of aroma, has caused a huge food waste and economic loss, which is a bottleneck restriction to the development of the breadmaking industry. Various bread improvers have been widely used to alleviate the issue. However, it is noteworthy that the sourdough technology has emerged as a pivotal factor in this regard. In sourdough, the metabolic breakdown of carbohydrates, proteins, and lipids leads to the production of exopolysaccharides, organic acids, aroma compounds, or prebiotics, which contributes to the preeminent ability of sourdough to enhance bread attributes. Moreover, sourdough exhibits a "green-label" feature, which satisfies the consumers' increasing demand for additive-free food products. In the past two decades, there has been a significant focus on sourdough with in situ produced dextran due to its exceptional performance. In this review, the behaviors of bread crucial compositions (i.e., starch and gluten) during dough mixing, proofing, baking and bread storing, as well as alterations induced by the acidic environment and the presence of dextran are systemically summarized. From the viewpoint of starch and gluten, results obtained confirm the synergistic amelioration on bread quality by the coadministration of acidity and dextran, and also highlight the central role of acidification. This review contributes to establishing a theoretical foundation for more effectively enhancing the quality of wheat breads through the application of in situ produced dextran.

Structural characteristics, digestion properties, fermentation properties, and biological activities of butyrylated starch: A review

Butyrylated starch is produced by the esterification of hydroxyl groups in starch with butyryl groups, which improves the structural diversity of starch and expands its function and biological activity. The paper summarizes the structural properties and digestive properties, fermentation properties, and biological activities of butyrylated starch and describes the conformational relationships generated by the butyryl groups to reveal the underlying mechanisms. The butyryl groups replace the hydroxyl groups in starch and break the hydrogen bonds, which consequently changes the molecular, crystal, and granular structures of starch, while the starch structure also affects the distribution of the butyryl groups. Binding to the butyryl groups gives starch efficacy in resisting digestion, lowering the glycaemic index, releasing butyric acid in the colon, and regulating intestinal flora and metabolites. Relationships between starch structural parameters and butyric acid production and intestinal flora were also concluded to provide guidance for the rational design of butyrylated starch to improve efficacy. Moreover, based on its digestive and fermentation properties, butyrylated starch has exhibited good therapeutic efficacy for intestinal diseases, diabetes, polycystic ovary syndrome, and chronic restraint stress-induced abnormalities. This review provides a valuable reference for butyrylated starch advancement and utilization.

A review of the effects of fermentation on the structure, properties, and application of cereal starch in foods

Fermentation is one of the oldest food processing techniques known to humans and cereal fermentation is still widely used to create many types of foods and beverages. Starch is a major component of cereals and the changes in its structure and function during fermentation are of great importance for scientific research and industrial applications. This review summarizes the preparation of fermented cereals and the effects of fermentation on the structure, properties, and application of cereal starch in foods. The most important factors influencing cereal fermentation are pretreatment, starter culture, and fermentation conditions. Fermentation preferentially hydrolyzes the amorphous regions of starch and fermented starches have a coarser appearance and a smaller molecular weight. In addition, fermentation increases the starch gelatinization temperature and enthalpy and reduces the setback viscosity. This means that fermentation leads to a more stable and retrogradation-resistant structure, which could expand its application in products prone to staling during storage. Furthermore, fermented cereals have potential health benefits. This review may have important implications for the modulation of the quality and nutritional value of starch-based foods through fermentation.

Functionalization Methods of Starch and Its Derivatives: From Old Limitations to New Possibilities

It has long been known that starch as a raw material is of strategic importance for meeting primarily the nutritional needs of people around the world. Year by year, the demand not only for traditional but also for functional food based on starch and its derivatives is growing. Problems with the availability of petrochemical raw materials, as well as environmental problems with the recycling of post-production waste, make non-food industries also increasingly interested in this biopolymer. Its supporters will point out countless advantages such as wide availability, renewability, and biodegradability. Opponents, in turn, will argue that they will not balance the problems with its processing and storage and poor functional properties. Hence, the race to find new methods to improve starch properties towards multifunctionality is still ongoing. For these reasons, in the presented review, referring to the structure and physicochemical properties of starch, attempts were made to highlight not only the current limitations in its processing but also new possibilities. Attention was paid to progress in the non-selective and selective functionalization of starch to obtain materials with the greatest application potential in the food (resistant starch, dextrins, and maltodextrins) and/or in the non-food industries (hydrophobic and oxidized starch).

Investigation on chain segment motions of various starch molecules under different glycerol-water system

The molecular motion of starch at different glycerol concentrations (0, 20, 50, and 80 %) was investigated using Electron Paramagnetic Resonance (EPR) spectroscopy. Fourier-transform infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (1H NMR) spectroscopy confirmed that hydroxyl groups at the C2 and C3 positions of glucose units in corn starch (CS), waxy corn starch (WCS), and high amylose corn starch (HCS) were labeled with 4-amino-TEMPO. The crystallinities of CS, WCS, and HCS after spin-labeling decreased from 30.68 % to 3.21 %, 39.36 % to 1.65 %, and 28.54 % to 8.08 %, respectively. The pseudoplastic fluid properties of the spin-labeled starch remained shear-thin at different glycerol concentrations. EPR revealed the fast- and slow-motion components of the spin-labeled starch molecules dispersed in water. At a glycerol concentration of 20 %, the slow-motion component disappeared, indicating a faster rotational motion of the starch chain segments. As the glycerol concentration increased to 50 and 80 %, the rotational motion slowed because of high viscosity. In particular, the mobility of the spin-labeled WCS chains increased owing to easier access of glycerol and water to the branched structure. This study directly observed the dynamics of the molecular behavior of starch in glycerol-water systems.

Study on the anti-retrogradation of wheat amylopectin by addition of alkali-soluble glutenin

The retrogradation of wheat amylopectin during cold storage is the main reason for the increasing hardness of flour products such as steamed bread, bread and pastries, etc. Addition of gluten protein components is a green, safe, cheap and efficient method to inhibit the retrogradation of wheat amylopectin. In this paper, as being stored at 4 °C for 7 d, retrogradation rate of wheat amylopectin decreased from 55.02 % to 14.37 % after it was mixed with 20 % alkali-soluble glutenin (ASG) at 30 °C for 90 min, a 73.8 % reduction. The infrared results showed that the intensity of bending vibration of water molecules and intra-molecular β-sheet content of ASG decreased during the interaction between amylopectin and ASG. Meanwhile, intermolecular β-sheet and random coil contents of ASG increased. The results of 13C Solid-state NMR indicated that Qβ, Pγ and Lγ of ASG involved in interaction of wheat amylopectin, ASG and molecule of water. Under the optimal conditions, the interaction of wheat amylopectin and ASG began to form spheres containing disulfide bonds, resulting in the attenuation or disappearance of the diffraction peak at 2θ 19.7°, which may be marked as the criterion for the best mixing time of wheat amylopectin and ASG. The retrogradation kinetic index (n) of wheat amylopectin decreased significantly with the addition of ASG and formation of disulfide bond was the key factor. ASG could be potentially used as an anti-retrogradation agent for amylopectin.

Enzymatic Modification of Starch Using Recombinant Genes from Sorghum in Escherichia coli: Insights and Potential Applications

SBEIIb (Sobic.004G163700), SSSIIa (Sobic.010G093400), and GBSSI (Sobic.010G022600) genes that regulate starch synthesis in sorghum endosperm were transferred into Escherichia coli by transgenic technology. SBEIIb, SSSIIa, and GBSSI enzymes were separated and purified through a Ni column and analyzed by electrophoresis with molecular weights and activities of 91.57 84.57, and 66.89 kDa and 551 and 700 and 587 U/μL, respectively. Furthermore, they were applied to starch modification, yielding interesting findings: the A chain content increased from 25.79 to 89.55% for SBEIIb-treated waxy starch, while SSSIIa extended the A chain to form DPs of the B chain, with A chain content decreasing from 89.55 to 37.01%, whereas GBSSI was explicitly involved in the synthesis of B1 chain, with its content increasing from 9.59 to 48.45%. Modified starch was obtained, which could be accurately applied in various industries. For instance, we prepared a sample (containing 89.6% A chain content) with excellent antiaging and antidigestion properties through SBEIIb modification. Moreover, higher RS3 (34.25%) and SDS contents (15.75%) of starch were obtained through the joint modification of SBEIIb and SSSIIa. These findings provide valuable insights for developing sorghum starch synthesis-related enzymes and offer opportunities for improving starch properties through enzymatic approaches.

Characterization of the physicochemical properties of Lipu Colocasia esculenta (L.) Schott starch: A potential new food ingredient

The physicochemical properties of Lipu taro starch (LTS), cassava starch (CS) and wheat starch (WS) were analyzed. These starches exhibited a comparable starch content (86 %). However, LTS had a significantly lower amylose content (15.93 %) compared to CS (26.62 %) and WS (33.53 %). Moreover, LTS demonstrated an irregular polygonal cubic morphology with a smaller particle size of 2.55 μm while possessed an A-type crystal structure with high crystallinity at 25.07 %. In contrast, CS and WS had larger particle sizes of 13.33 μm and 16.68 μm, respectively, with lower crystallinities of 22.52 % and 20.33 %. Due to these physicochemical properties, LTS exhibited superior emulsification properties with a higher emulsifying activity index of 8.63 m2/g and an emulsion stability index of 69.18 min, whereas CS and WS had values of 2.35 m2/g and 25.15 min, and 0.37 m2/g and 11.48 min, respectively. LTS also demonstrated enhanced thermal stability, characterized by higher gelatinization temperature (indicated by To, Tp, Tc, and ΔT) and reduced paste viscosity (indicated by PV, TV, FV, SBV, and BDV) compared to CS. However, the mechanical strength of the gel made from LTS (indicated by hardness, adhesiveness, springiness, gumminess, and chewiness) was comparatively inferior to those from CS and WS.

Effects of starch multiscale structure on the physicochemical properties and digestibility of Radix Cynanchi bungei starch

Radix Cynanchi bungei (RCb) contains 40-70 % starch, yet little is known about the structure and properties of RCb starch. In this study, the multiscale structure of two cultivars of RCb starch (YW201501 and BW201001) were characterized, and the effects of starch structure on its physicochemical properties were investigated. The differences in physicochemical properties of RCb starch were influenced by its multiscale structure. The starch granules were round and irregular polygon, with sizes ranging between 2 and 14 μm. YW201501 had a higher amylose (21.81 %) and lipid (0.96 %) content, molecular weight (59.5 × 106 g/mol), and A chain proportion (27.5 %), and a lower average granule size (6.14 μm), amylopectin average chain length (19.7), and B3 chain proportion (10.3 %). Both starches were B-type crystalline, with higher crystallinity (26.3 %) and R1047/1022 (0.74) for YW201501, resulting in large gelatinization enthalpy. In addition, the higher peak viscosity and larger retrogradation degree of YW201501 were correlated to its higher amylose content. In vitro digestibility revealed that the low rapidly digestible starch and high resistant starch of BW201001 were related to the fine structure of starch. YW201501 and BW201001 had a medium glycemic index (62.6-66.0) with potential for processing into healthy starchy foods.

The interaction and physicochemical properties of the starch-polyphenol complex: Polymeric proanthocyanidins and maize starch with different amylose/amylopectin ratios

This study investigated the impact of polymeric proanthocyanidins (PPC) on the physicochemical characteristics of maize starch with varying amylose content, and their potential interaction mechanism. PPC with a lower content (1 %) reduced the viscoelasticity of the high amylose maize starch (HAM) system, inhibited amylose rearrangement, and enhanced its fluidity. However, excessive PPC restrained the interaction between PPC and amylose. In contrast to HAM, PPC improved the gelation ability of waxy maize starch (WAM) as PPC concentration was raised. PPC suppressed the recrystallization of starch during storage, and PPC had a superior inhibition influence on the retrogradation of WAM in comparison to HAM. This indicated that amylopectin was more likely to interact with PPC than amylose. Hydrogen bonds were the main driving force between PPC and starch chains, which was clarified by Fourier transform-infrared, nuclear magnetic resonance, X-ray diffraction, iodine bonding reaction, and dynamic light scattering data. Additionally, the mechanism of interaction between PPC and the two starch components may be similar, and variance in physicochemical attributes can be primarily credited to the percentage of amylose to amylopectin in starch.

Physicochemical, thermal, pasting, morphological, functional and bioactive binding characteristics of starches of different oat varieties of North-Western Himalayas

Starches were isolated from five oat varieties (SFO-1, SFO-3, Sabzar, SKO-20 and SKO-96) grown in North-Western Himalayas of India. Moisture content of the varieties ranged from 9.25 ± 0.09 to 13.21 ± 0.11 %, indicating their shelf-stability. Results suggested >90 % purity of starches as was evident from values of ash, proteins, and lipids. Amylose content results showed that all starches fall within category of intermediate-amylose starches. Lambdamax, blue value and OD620/550 were found significantly (p ≤ 0.05) higher in SKO-20. Sabzar exhibited higher starch hydrolysis percentage of 85.16 % whereas, lowest was observed in SKO-20 (78.12 %). Degree of syneresis was higher in SKO-20 however, its freeze-thaw stability was lesser. Wide peak in FTIR spectra at 3320 cm-1 confirms nature of starches. SKO-20 exhibited significantly higher onset gelatinization temperature (65.19 ± 1.06 °C) and enthalpy (15.78 ± 0.15 J/g) whereas, Sabzar exhibited lowest enthalpy. Pasting characteristics indicated lowest and highest final viscosity in SKO-20 (341.30 ± 2.11 mPas) and SKO-96 (1470 ± 4.56 mPas), respectively. SEM results indicated irregular and polygonal shape of starches with size <10 μm. SKO-20 exhibited lowest disintegration time of 2.08 ± 0.01 min and Sabzar showed highest (3.31 ± 0.07 min). SKO-20 released more curcumin (71.28 %) whereas, Sabzar released less. This suggests that SKO-20 could be used as better excipient for delivery of curcumin at target site.

Sodium Starch Glycolate (SSG) from Sago Starch (Metroxylon sago) as a Superdisintegrant: Synthesis and Characterization

The characteristics of sago starch exhibit remarkable resemblances to those of cassava, potato, and maize starches. This review intends to discuss and summarize the synthesis and characterization of sodium starch glycolate (SSG) from sago starch as a superdisintegrant from published journals using keywords in PubMed, Scopus, and ScienceDirect databases by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020). There are many methods for synthesizing sodium starch glycolate (SSG). Other methods may include the aqueous, extrusion, organic solvent slurry, and dry methods. Sago starch is a novel form of high-yield starch with significant development potential. After cross-linking, the phosphorus content of sago starch increases by approximately 0.3 mg/g, corresponding to approximately one phosphate ester group per 500 anhydroglucose units. The degree of substitution (DS) of sodium starch glycolate (SSG) from sago ranges from 0.25 to 0.30; in drug formulations, sodium starch glycolate (SSG) from sago ranges from 2% to 8% w/w. Higher levels of sodium starch glycolate (SSG) (2% and 4% w/w) resulted in shorter disintegration times (within 1 min). Sago starch is more swellable and less enzymatically digestible than pea and corn starch. These investigations demonstrate that sago starch is a novel form of high-yield starch with tremendous potential for novel development as superdisintegrant tablets and capsules.

Comparative studies on physicochemical properties of three potato varieties different in RS2 and RS3 contents

BACKGROUND

At present, increasing importance has been attracted to healthy food enriched in resistant starch (RS), which has great benefits in health-promoting. Raw potato has rich RS2, whereas most RS2 may become digestible after gelatinization, resulting in few RS being left in processed potato. Breeding potatoes with high RS2 or RS3 or both can meet the demand for various healthy potato products.

RESULTS

There were apparent discrepancies among three potatoes with contrast RS2 and RS3 content in thermal properties, viscosity and digestibility. ZS-5 had the highest RS2 with 50.17% but the lowest RS3 with 3.31%. Meanwhile, ZS-5 had the largest starch granule, the highest proportion of B3, viscosity and hardness, and the highest digestibility. DN303 with the highest content of RS3 (5.08%) had the lowest hardness and fracturability. MG56-42 with both higher RS2 and RS3 content showed the highest resistance to digestion and moderate hardness and fracturability.

CONCLUSION

The present study enriches the potential resources and provides a reliable scientific basis for high RS potatoes breeding. The various features of different potatoes make it possible to screen potatoes according to different demands. © 2023 Society of Chemical Industry.

Smart stimuli-responsive polysaccharide nanohydrogels for drug delivery: a review

Polysaccharides have found extensive utilization as biomaterials in drug delivery systems owing to their remarkable biocompatibility, simple functionalization, and inherent biological properties. Within the array of polysaccharide-based biomaterials, there is a growing fascination for self-assembled polysaccharide nanogels (NG) due to their ease of preparation and enhanced appeal across diverse biomedical appliances. Nanogel (or nanohydrogel), networks of nanoscale dimensions, are created by physically or chemically linking polymers together and have garnered immense interest as potential carriers for delivering drugs due to their favorable attributes. These include biocompatibility, high stability, the ability to adjust particle size, the capacity to load drugs, and their inherent potential to modify their surface to actively target specific cells or tissues via the attachment of ligands that can recognize corresponding receptors. Nanogels can be engineered to respond to specific stimuli, such as pH, temperature, light, or redox conditions, allowing controlled release of the encapsulated drugs. This intelligent targeting capability helps prevent drug accumulation in unintended tissues and reduces the potential side effects. Herein, an overview of nanogels is offered, comprising their methods of preparation and the design of stimulus-responsive nanogels that enable controlled release of drugs in response to specific stimuli.

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Thermal processing remains the key processing technology for food products. However, there are some limitations for thermal processing such as loss of sensory and nutritional quality. Furthermore, nowadays consumers are looking forward for fresh like products which are free from chemical preservatives, yet having longer shelf life. Thus, alternative processing techniques are gaining popularity among food processors to replace conventional thermal processing keeping nutritional quality, sensory attributes and food safety in mind. The alternative processing techniques such as ultrasound, gamma irradiation, high pressure processing and microwave treatment causes several modifications (structural changes, effects on swelling and solubility index, gelatinization behaviour, pasting or rheological properties, retrogradation and cooking time) in physicochemical and functional properties of pulse starches which offers several advantages from commercial point of view. This review aims to summarize the effect of different alternative processing techniques on the structure, solubility, gelatinization, retrogradation and pasting properties of various pulse starches.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05557-3.

Production of Kudzu Starch Gels with Superior Mechanical and Rheological Properties through Submerged Ethanol Exposure and Implications for In Vitro Digestion

Producing starch gels with superior mechanical attributes remains a challenging pursuit. This research sought to develop a simple method using ethanol exposure to produce robust starch gels. The gels' mechanical properties, rheology, structural characteristics, and digestion were assessed through textural, rheological, structural, and in vitro digestion analyses. Our investigation revealed an improvement in the gel's strength from 62.22 to178.82 g. The thermal transitions were accelerated when ethanol was elevated. The exposure to ethanol resulted in a reduction in syneresis from 11% to 9.5% over a period of 6 h, with noticeable changes in size and color. Rheologically, the dominating storage modulus and tan delta (<0.55) emphasized the gel's improved elasticity. X-ray analysis showed stable B- and V-type patterns after ethanol exposure, with relative crystallinity increasing to 7.9%. Digestibility revealed an ethanol-induced resistance, with resistant starch increasing from 1.87 to 8.73%. In general, the exposure to ethanol played a crucial role in enhancing the mechanical characteristics of kudzu starch gels while simultaneously preserving higher levels of resistant starch fractions. These findings have wide-ranging implications in the fields of confectioneries, desserts, beverages, and pharmaceuticals, underscoring the extensive academic and industrial importance of this study.

The effect of heat-moisture treatment changed the binding of starch, protein and lipid in rice flour to affect its hierarchical structure and physicochemical properties

This study investigated the effect of removing proteins, lipids and starch on the structure, physicochemical properties and digestion properties of rice flour (with 30% moisture) treated with heat moisture treatment (HMT). According to the results, HMT caused the adhesion and agglomeration of the rice flour, promoted the binding between starch, protein and lipid molecular chains and led to the formation of complexes (especially starch-lipid complexes), which hindered the removal of non-starch components. Compared to the untreated rice flour, the HMT treated lipid-removal rice flour had small changes in their crystallinity, gelatinization temperature and viscosity property. After removing protein, the crystallinity, peak viscosity, final viscosity, breakdown and starch digestibility were sharply increased. In particular, the peak viscosity increased from 811 cP to 1746 cP and the enthalpy change increased from 5.33 J/g to 10.18 J/g. These findings are helpful in understanding the contribution of removing endogenous proteins and lipids to the physicochemical changes of HMT treated rice flour during its heating process and thus can be helpful in controlling the quality of rice flour through HMT.

High fructan barley lines produced by selective breeding may alter β-glucan and amylopectin molecular structure

Six cross-bred barley lines developed by a breeding strategy with the target to enhance the fructan synthesis activity and reduce the fructan hydrolysis activity were analyzed together with their parental lines, and a reference line (Gustav) to determine whether the breeding strategy also affected the content and molecular structure of amylopectin and β-glucan. The highest fructan and β-glucan content achieved in the novel barley lines was 8.6 % and 12 %, respectively (12.3-fold and 3.2-fold higher than in Gustav). The lines with low fructan synthesis activity had higher starch content, smaller building blocks in amylopectin, and smaller structural units of β-glucans than the lines with high-fructan synthesis activity. Correlation analysis confirmed that low starch content was associated with high amylose, fructan, and β-glucan content, and larger building blocks in amylopectin.

Sustainable polysaccharide and protein hydrogel-based packaging materials for food products: A review

Sustainable food packaging is a necessary element to ensure the success of a food system, the accomplishment of which is weighed in terms of quality retention and ensured products safety. Irrespective of the raised environmental concerns regarding petroleum-based packaging materials, a sustainable analysis and a lab to land assessment should be a priority to eliminate similar fates of new material. Functionalized bio-based hydrogels are one of the smartest packaging inventions that are expected to revolutionize the food packaging industry. Although in this review, the focus relies on recent developments in the sustainable bio-based hydrogel packaging materials, natural biopolymers such as proteins and polysaccharides from which hydrogels could be obtained, the challenges encountered in hydrogel-based packaging materials and the future prospects of hydrogel-based food packaging materials are also discussed. Moreover, the need for 'Life Cycle Assessment' (LCA), stress on certifications and a sustainable waste management system is also suggested which can bring both food and packaging into the same recycling bins.

Avocado seed starch: Effect of the variety on molecular, physicochemical, and digestibility characteristics

Agro-industrial residues can increase environmental pollution owing to poor knowledge of the use of some components, such as dietary fiber, protein, starch, minerals, and bioactive compounds, which can be used in the food industry. This study compared the molecular, physicochemical, and digestibility characteristics of three avocado seed starches (Criolla, Fuerte, and Hass). Starch was extracted through successive washing and sedimentation. The morphology, size distribution, thermal properties, pasting properties, infrared spectra with Fourier transform, size distribution of amylopectin chains, and digestibility of the three avocado seed strains were analyzed. The starch grains were oval and spherical in shape. The average size of Criolla avocado starch (24.55 μm) was the largest, followed by Hass and Fuerte starches (21.37 μm). Higher gelatinization enthalpy (8.55 J/g), gelatinization temperature (75.28 °C), and pasting temperature (75.57 °C) were observed for Fuerte avocado starch, followed by Hass and Criolla starches. Hass avocado starch exhibited higher maximum (836.27 mPa.s), final (1407.37 mPa.s), setback (588.78 mPa.s), and breakdown (17.68 mPa.s) viscosities than Criolla and Fuerte avocado starches. In addition, the probed avocado starches exhibited high content of resistant starch (60.06-68.90%). Therefore, it was demonstrated that differences in the chemical composition and structure of avocado starch can affect the digestibility of native starch.

Techno-functional properties of gluten-free pasta from hyperprotein quinoa flour

Many consumers who are aware of the importance of good nutrition demand quality food alternatives. In particular, many of them are looking for quality, plant-based protein sources such as quinoa. The objective of this work was to evaluate the techno-functional properties of gluten-free pasta from hyperprotein quinoa flour. Pasta mixes were made from gluten-free flours, corn, rice, cassava starch, hyperprotein quinoa flour and defatted high protein quinoa flour, which were subsequently extruded. The flow rheological properties of aqueous dispersions of flour mixtures were analyzed before and after the pasting test. In addition, thermal properties were analyzed by differential scanning calorimetry and structural properties by Fourier transform infrared spectroscopy. The results showed a change of flow from dilatant (n > 1) to pseudoplastic (n < 1) after the pasting test. In addition, a positive correlation was observed between hyperprotein defatted quinoa flour and viscosity, and a negative correlation with hyperprotein quinoa flour. Regarding thermal properties, it was found that all blends showed low gelatinization enthalpy values, attributed to the high proportions of HQF and HDQF. Spectroscopic analysis showed that the extrusion did not significantly affect the native structure of the protein, by monitoring the intensities of the 1648 cm-1, 1656 cm-1 and 1667 cm-1 bands associated with the Random coil, α-helix, β-turns secondary structures, respectively. It was possible to conclude that both hyperprotein quinoa flour and defatted hyperprotein quinoa flours have a differential influence on the techno-functional properties of pasta. The first one, tends to reduce viscosity and consistency while the second one tends to increase it. Finally, moderate temperatures during extrusion did not cause significant changes in starch and protein structures as determined by spectroscopic study.

Moderate Reduction in Nitrogen Fertilizer Results in Improved Rice Quality by Affecting Starch Properties without Causing Yield Loss

The quality and starch properties of rice are significantly affected by nitrogen. The effect of the nitrogen application rate (0, 180, and 230 kg ha^-1) on the texture of cooked rice and the hierarchical structure and physicochemical properties of starch was investigated over two years using two japonica cultivars, Bengal and Shendao505. Nitrogen application contributed to the hardness and stickiness of cooked rice, reducing the texture quality. The amylose content and pasting properties decreased significantly, while the relative crystallinity increased with the increasing nitrogen rates, and the starch granules became smaller with an increase in uneven and pitted surfaces. The proportion of short-chain amylopectin rose, and long-chain amylopectin declined, which increased the external short-range order by 1045/1022 cm^-1. These changes in hierarchical structure and grain size, regulated by nitrogen rates, synergistically increased the setback viscosity, gelatinization enthalpy and temperature and reduced the overall viscosity and breakdown viscosity, indicating that gelatinization and pasting properties were the result of the joint action of several factors. All results showed that increasing nitrogen altered the structure and properties of starch, eventually resulting in a deterioration in eating quality and starch functional properties. A moderate reduction in nitrogen application could improve the texture and starch quality of rice while not impacting on the grain yield.

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.

Advances in Starch Nanoparticle for Emulsion Stabilization

Starch nanoparticles (SNPs) are generally defined as starch grains smaller than 600-1000 nm produced from a series of physical, chemical, or biologically modified starches. Many studies have reported the preparation and modification of SNPs, which are mostly based on the traditional "top-down" strategy. The preparation process generally has problems with process complexity, long reaction periods, low yield, high energy consumption, poor repeatability, etc. A "bottom-up" strategy, such as an anti-solvent method, is proven to be suitable for the preparation of SNPs, and they are synthesized with small particle size, good repeatability, a low requirement on equipment, simple operation, and great development potential. The surface of raw starch contains a large amount of hydroxyl and has a high degree of hydrophilicity, while SNP is a potential emulsifier for food and non-food applications.

Impact of Starch Concentration on the Pasting and Rheological Properties of Gluten-Free Gels. Effects of Amylose Content and Thermal and Hydration Properties

The pasting and rheological properties of starch gels from different botanical origins have been widely used to evaluate the application of these starches in pharmaceutical and food products. However, the ways in which these properties are modified by starch concentration and their dependence on amylose content and thermal and hydration properties have not been adequately established so far. An exhaustive study of the pasting and rheological properties of starch gels (maize and rice (normal and waxy in both cases), wheat, potato, and tapioca) at concentrations of 6.4, 7.8, 9.2, 10.6, and 11.9 g/100 g was performed. The results were evaluated in terms of a potential equation fit between each parameter and each gel concentration. The parameters determined for the gels at the studied concentrations were correlated with the hydration properties and thermal properties by applying principal component analysis (PCA). Wheat starch, followed by normal maize and normal rice starches, presented a greater capacity to modulate their gels' pasting and viscoelastic properties via their concentration in water. On the contrary, the characteristics of waxy rice and maize, potato, and tapioca starches were barely modified by concentration in pasting assays, but the gels of potato and tapioca showed noticeable changes in their viscoelastic properties as functions of concentration. In the PCA plot, the non-waxy cereal samples (wheat, normal maize, and normal rice) were located close to each other. Wheat starch gels were the most dispersed on the graph, which is consistent with the high dependence on the concentration of the gel shown in most of the studied parameters. The waxy starches had close positions not too distant from those of the tapioca and potato samples and with little influence from amylose concentration. The potato and tapioca samples were close to the vectors of the crossover point in rheology and peak viscosity in their pasting properties. The knowledge gained from this work allows a better understanding of the effects of starch concentration on food formulations.

Impact of crystalline structure on the digestibility of amylopectin-based starch-lipid complexes

In this study, chain-elongated waxy corn starch (mWCS) was complexed with lauric acid (LA) to produce starch-lipid complexes (mWCS@LA) with a mixture of B- and V-type crystalline structures. Results from in vitro digestion showed that mWCS@LA had higher digestibility than mWCS, and the logarithm of slope plots of mWCS@LA revealed a two-stage digestion pattern, with digestion rate of the first stage (k₁ = 0.038 min^-1) being much higher than that of the following stage (k₂ = 0.0116 min^-1). The complexation between the long branch chains of mWCS and LA formed amylopectin-based V-type crystallites that were rapidly hydrolyzed during the first stage. The digesta isolated from the second stage of digestion had a B-type crystallinity of 52.6 %, and starch chains with degree of polymerization of 24-28 mainly contributed to the formation of the B-type crystalline structure. The results from the present study reveal that the B-type crystallites were more resistant to amylolytic hydrolysis than the amylopectin-based V-type crystallites.

Molecular structure of lotus seed amylopectins and their beta-limit dextrins

Investigation on amylopectin molecular structure is gaining importance for understanding the properties of starch. Lotus seeds are a novel starch source with high apparent amylose content. Current understanding on the molecular structure of amylopectin in lotus seed starch is scarce. This study compared the molecular structure of a range of lotus seed amylopectins with those of maize and potato amylopectins. Internal structures of these amylopectins were compared via investigating the chain length distribution of their β-limit dextrins. The average lengths and molar compositions of unit chains in lotus seed amylopectins and their β-limit dextrins fell generally between those of maize and potato. The average chain lengths of lotus seed, maize, and potato amylopectins were 19.95 (on average), 19.11, and 21.19 glucosyl units, respectively. Lotus seed amylopectins had higher weight proportion of clustered unsubstituted chains (44.94 % on average) than those of potato (43.99 %) and maize amylopectins (42.95 %). Results of correlation analysis indicated that apparent amylose content of LS were related to structural characteristics of its amylopectin due to the presence of long external chains. The results of this study are of fundamental importance for the utilization of lotus seed starch as a novel starch source.

Structural, functional and mechanistic insights uncover the role of starch in foxtail millet cultivars with different congee-making quality

Ten foxtail millet cultivars with different congee-making quality were investigated for relationships between starch structures, functional properties and congee-making qualities. Swelling power, pasting peak viscosity (PV) and setback (SB), gel hardness and resilience, and gelatinization onset (T_o), peak (T_p) and range (R) temperature were correlated with congee-making performance significantly. Good eating-quality cultivars with these parameters were in the range of 15.41-18.58 %, 3095-3279 cp, 1540-1745 cp, 430-491 g, 0.47-0.57, 64.43-65.28 °C, 69.97-70.32 °C and 23.38-24.52 °C, respectively. Correlation analysis showed that amylose, amylopectin B₂ chains and A₂₁ were essential parameters controlling the functional properties. Amylose molecules with linear molecular morphology would cause crystal defects and a wide range of molecular weight distribution. Additionally, they were more prone to re-association, which influenced the PV, SB, T_o, T_p and gel hardness. B₂ chains impacted the gelatinization temperature range (R), gel resilience and swelling behavior by affecting the alignment of double helices and the size of starch particles and pores. Starch with more binding sites of bound water (A₂₁) tended to leach from the swelling granules easily and contributed to higher values of PV. The content of amylose, B₂ chains and A₂₁ of good eating-quality cultivars were 16.19-18.46 %, 11.60-11.69 % and 96.50-97.02 %, respectively.

Rapid screening of sixty potato cultivars for starch profiles to address a consumer glycemic dilemma

Potatoes are a dietary staple consumed by a significant portion of the world, providing valuable carbohydrates and vitamins. However, most commercially produced potatoes have a high content of highly branched amylopectin starch, which generally results in a high glycemic index (GI). Consumption of foods with high levels of amylopectin elicit a rapid spike in blood glucose levels, which is undesirable for individuals who are pre-diabetic, diabetic, or obese. Some cultivars of potatoes with lower amylopectin levels have previously been identified and are commercially available in niche markets in some countries, but they are relatively unavailable in the United States and Latin America. The high glycemic index of widely available potatoes presents a problematic "consumer's dilemma" for individuals and families that may not be able to afford a better-balanced, more favorable diet. Some native communities in the Andes (Bolivia, Chile, and Peru) reportedly embrace a tradition of providing low glycemic tubers to people with obesity or diabetes to help people mitigate what is now understood as the negative effects of high blood sugar and obesity. These cultivars are not widely available on a global market. This study examines 60 potato cultivars to identify potatoes with low amylopectin. Three independent analyses of potato starch were used: microscopic examination of granule structure, water absorption, and spectrophotometric analysis of iodine complexes to identify potato cultivars with low amylopectin Differences among cultivars tested were detected by all three types of analyses. The most promising cultivars are Huckleberry Gold, Muru, Multa, Green Mountain, and an October Blue x Colorado Rose cross. Further work is necessary to document the ability of these low amylopectin cultivars to reduce blood glucose spike levels in human subjects.

The Properties of Different Starches under the Influence of Glucono-Delta-Lactone at Different Concentrations

In this study, glucono-delta-lactone (GDL), which is Generally Recognized as Safe (GRAS), was added to native starches to modify their physicochemical properties. The effects of GDL on the molecular weight, pasting properties, flow behavior, gel syneresis, and crystallization properties of potato, tapioca, and corn starches were investigated. GPC results showed that as the GDL concentration increased, the molecular weight of amylose increased, whereas that of amylopectin decreased. An analysis using the Rapid Visco Analyzer revealed that the addition of GDL improved the pasting properties of potato starch, with reduced peak viscosity and breakdown viscosity, and it also improved setback viscosity. On the other hand, tapioca starch degraded substantially after GDL addition, indicating a lower tendency for short-term retrogradation, as reflected in the lower setback viscosity. The effects of GDL on corn starch pasting properties were very similar to those observed for tapioca starch, but the changes were relatively subtle. In terms of flow behavior, GDL addition decreased and increased the flow index values of the potato and tapioca starch pastes, respectively. However, the effect of GDL addition on the flow index value of the corn starch paste was found to be insignificant. The results also showed that the percentage of syneresis under the influence of GDL depended on the starch botanical origin-that is, potato starch, 14-18%, tapioca starch, 10-13%, and corn starch, 17-20%-which was substantiated by crystallinity analysis. It was observed that GDL has the potential to be used for starch modification because it creates desirable functionalities with the advantage of being a green-labelled ingredient.

Physicochemical properties of starch in sodium chloride solutions and sucrose solutions: Importance of starch structure

The influences of sodium chloride (NaCl)/sucrose on starch properties as affected by starch structural characteristics are little understood. In this study, the effects were observed in relation to the chain length distribution (from size exclusion chromatography) and granular packing (inferred through morphological observation and determination of swelling factor and paste transmittance) of starches. Adding NaCl/sucrose dramatically delayed the gelatinization of starch that had a high ratio of short-to-long amylopectin chains and had loose granular packing. The effects of NaCl on the viscoelasticity of gelatinizing starch were related to the flexibility of amylopectin internal structure. Effects of NaCl/sucrose on starch retrogradation varied with starch structure, co-solute concentration, and analytical method. The co-solute-induced changes in retrogradation were highly associated with amylose chain length distribution. Sucrose strengthened the weak network formed by short amylose chains, while the effect was not significant on amylose chains that were capable of forming strong networks.

Non-conventional starches isolated from agronomic-improved beans (Phaseolus vulgaris L.): a study of their structure and physicochemical properties

BACKGROUND

Non-conventional starch sources are promising alternative food ingredients. Different bean varieties with agronomic improvements are constantly being developed and cultivated in the Northwestern Argentinean region (NOA) to increase yields and obtain high-quality seeds. However, the main attributes of their starches have not been studied. In this work, starches from four agronomic-improved bean cultivars were isolated and their structure and physicochemical properties were evaluated.

RESULTS

High-purity starches were obtained, as shown by their low protein and ash content. Starch granules presented smooth surfaces with spherical to oval shapes, with a marked 'Maltese cross' and heterogeneous sizes. Their amylose content revealed a mean value of 318 g kg^-1 and all presented resistant > slowly digestible > rapidly digestible starch fractions. Their Fourier transform infrared spectra were similar and X-ray diffraction analysis showed a C_A -type pattern in all cases despite their different sources. Among thermal properties, Escarlata starch showed the lowest gelatinization peak temperature (69.5 °C) and Anahí starch the highest (71.3 °C). Starch pasting temperature varied from 74.6 to 76.9 °C, whereas peak viscosity and final viscosity showed a similar tendency, with Leales B30 < Anahí < Escarlata < Cegro 99/11-2 and Leales B30 < Anahí = Escarlata < Cegro 99/11-2, respectively.

CONCLUSION

This study provides the basis for a better understanding of the characteristics of agronomic-improved NOA bean starches, enabling their use in product formulation as an alternative to starches from conventional sources. © 2023 Society of Chemical Industry.

Potato thermoplastic starch nanocomposite films reinforced with nanocellulose

Potato is a widely available feedstock with biocompatibility and biodegradability properties, making it a strong candidate for producing thermoplastic starch. The application of thermoplastic starch to replace petroleum-based plastic as a sustainable and environmentally friendly approach led to its further improvement through various techniques such as modification and filler reinforcement. Numerous studies have been done addressing the properties enhancement of potato thermoplastic starch through filler reinforcement including nanocellulose. This review focus on the recent and future potential of potato-based starch as one of the feedstocks for producing potato thermoplastic starch composites reinforced with nanocellulose.

Dibasic Magnesium Hypochlorite as an Oxidant to Tune Pasting Properties of Potato Starch in One Step

Modified starches are used widely in the food industry but often have a low nutritional value, lacking minerals vital for the human body, such as magnesium. Magnesium addition to native starches has been shown to result in changes in pasting properties. However, little work has been done on the addition of magnesium and other divalent cations to highly oxidised starches. In this work, we used dibasic magnesium hypochlorite (DMH) to oxidise potato starch to an industrially relevant degree of oxidation while at the same time introducing magnesium into the starch structure. We found that magnesium incorporation changes the pasting properties of starch and increases the gelatinisation temperature significantly, possibly due to an ionic cross-linking effect. These properties resemble the properties found for heat-moisture-treated potato starches. This change in properties was found to be reversible by performing a straightforward exchange of metal cations, either from sodium to magnesium or from magnesium to sodium. We show in this work the potential of the addition of divalent cations to highly oxidised starches in modifying the rheological and pasting properties of these starches and at the same time adding possible health benefits to modified starches by introducing magnesium.

Novel Approach for Quantitative Characterization of Short-Range Molecular Order in Gelatinized Starch by X-ray Diffraction

A novel quantitative method was developed to characterize short-range molecular order in gelatinized wheat and potato starches using X-ray diffraction (XRD). Gelatinized starches with different amounts of short-range molecular order and amorphous starches with no short-range molecular order were prepared and characterized by the intensity and area of Raman spectral bands. The degree of short-range molecular order in the gelatinized wheat and potato starches decreased with increasing water content used for gelatinization. By comparing XRD patterns of gelatinized and amorphous starch, the XRD peak at 33° (2θ) was shown to be typical of gelatinized starch. The relative peak area (RPA), intensity, and full width at half-maximum (FWHM) of the XRD peak at 33° (2θ) decreased with the increase in water content for gelatinization. We propose that the RPA of the XRD peak at 33° (2θ) can be used to quantify the amount of short-range molecular order in gelatinized starch. The method developed in this study will help to explore and understand the relationship between the structure and functionality of gelatinized starch in food and nonfood applications.

Glycoside hydrolases active on microbial exopolysaccharide α-glucans: structures and function

Glucose is the most abundant monosaccharide in nature and is an important energy source for living organisms. Glucose exists primarily as oligomers or polymers and organisms break it down and consume it. Starch is an important plant-derived α-glucan in the human diet. The enzymes that degrade this α-glucan have been well studied as they are ubiquitous throughout nature. Some bacteria and fungi produce α-glucans with different glucosidic linkages compared with that of starch, and their structures are quite complex and not fully understood. Compared with enzymes that degrade the α-(1→4) and α-(1→6) linkages in starch, biochemical and structural studies of the enzymes that catabolize α-glucans from these microorganisms are limited. This review focuses on glycoside hydrolases that act on microbial exopolysaccharide α-glucans containing α-(1→6), α-(1→3), and α-(1→2) linkages. Recently acquired information regarding microbial genomes has contributed to the discovery of enzymes with new substrate specificities compared with that of previously studied enzymes. The discovery of new microbial α-glucan-hydrolyzing enzymes suggests previously unknown carbohydrate utilization pathways and reveals strategies for microorganisms to obtain energy from external sources. In addition, structural analysis of α-glucan degrading enzymes has revealed their substrate recognition mechanisms and expanded their potential use as tools for understanding complex carbohydrate structures. In this review, the author summarizes the recent progress in the structural biology of microbial α-glucan degrading enzymes, touching on previous studies of microbial α-glucan degrading enzymes.