Starch Molecules Research Articles

Development, characterization, and evaluation of Zn-SA-chitosan bionanoconjugates on wheat seed, experiencing chilling stress during germination

This study aimed to develop and characterize the chitosan bionanoconjugates (BNCs) loaded with zinc (Zn) and salicylic acid (SA) and test their efficacy on wheat seed exposed to chilling stress. BNCs developed were spherical (480 ± 6.0 nm), porous, and positively charged (+25.2 ± 2.4 mV) with regulated nutrient release properties. They possessed complexation efficiency of 78.4 and 58.9 % for Zn, and SA respectively. BET analysis further confirmed a surface area of 12.04 m2/g. Release kinetics substantiated the release rates of Zn and SA, as 0.579 and 0.559 % per hour, along with a half-life of 119.7 and 124.0 h, respectively. BNCs positively affected the germination potential of wheat seeds under chilling stress as observed by significantly (p < 0.05) reduced mean emergence time (18 %), and increased germination rate (22 %), compared to the control. Higher activities of reserve mobilizing enzymes (α-amylase- 6.5 folds, protease −10.2 folds) as well as faster reserve mobilization of starch (64.4 %) and protein (63.5 %) molecules were also observed. The application further led to increased levels of the antioxidant enzymes (SOD and CAT) and reduced oxidative damage (MDA and H2O2). Thus, it is inferred that the developed BNCs could help substantially improve the germination and reserve mobilization potential, thereby increasing the crop yield.

Analysis of the relationship between starch molecular conformation and enzymatic hydrolysis efficiency

Resistant starch (RS) is important in controlling diabetes. The primary objective of this study is to examine the impact of molecular conformation on the enzymatic hydrolysis efficiency of starch by α-amylase. And the interactions between starch molecules with different conformations and α-amylase were analysed by using molecule dynamics simulation and molecular docking. It was found, the natural conformational starch molecule was hydrolysed from the middle of the starch chain by α-amylase, producing polysaccharides. The bent PS-conformational starch molecules with multiple O2-O3 intramolecular hydrogen bonds produced by high-pressure was hydrolysed from the head of the starch chain to produce glucose, which is not conducive to RS formation. The stretched H-conformation without intramolecular hydrogen bonds produced by heat treatment was not hydrolysed by α-amylase. However, it occupied the active groove and formed strong interactions with α-amylase, which prevented other starch molecules from binding to α-amylase, thus reducing hydrolysis efficiency. Moreover, the total interaction energies between the three starch molecules and α-amylase were approximately 78 kJ/mol. And several hydrogen bonds were formed between the starch molecules and α-amylase, which provides evidence for the continuous sliding hydrolysis hypothesis of α-amylase. Moreover, these results provide an important reference for elucidating the mechanism of RS formation.

Characterization of feruloylated arabinoxylan - acorn starch double network gel composite film and its application in postharvest preservation of Agaricus bisporus

To obtain efficient natural food packaging materials, we utilized acorn starch (AS)-based film strengthened by feruloylated arabinoxylan (FAX) gel and additional retrogradation treatment to extend the shelf life of Agaricus bisporus (A. bisporus). Fourier transform infrared spectroscopy (FT-IR), confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) analyses showed that due to the strong hydrogen bonding between FAX and starch molecules, physical crosslinking occurred between FAX and starch molecules in the composite film, and the microstructure became more compact. Thermogravimetric, tensile strength and swelling degree analyses indicate that the composite film exhibits better thermal stability, mechanical properties, and waterproofing compared to the pure AS film. Consequently, after five days of storage, the moisture content of the A. bisporus packaged with our composite film was 7.53 times and 5.73 times higher than that of the control group and the commercially available PEF group, respectively. Moreover, it delayed the respiration or transpiration of A. bisporus (lower weight loss, relative conductivity, MDA content). This packaging film developed with the objective of eco-friendly and biodegradability has considerable application potential in food and other industries.

Combined role of stearic acid and maleic anhydride in the development of thermoplastic starch-based materials with ultrahigh ductility and durability

The diverse properties reported for starch-based materials indicate their potential for use in the preparation of biodegradable flexible actuators. However, their natural brittleness and lack of durability after modification limit their practical application. Therefore, we propose a strategy for preparing flexible starch-based composites. The results of macro/micro property characterizations and molecular dynamics simulations indicated that using starch, maleic anhydride, and stearic acid (SA), the mobility of the starch chains was enhanced and retrogradation was inhibited through the synergistic effects induced by chain breaking, complex formation with SA, and esterification of the starch molecules. In addition, the elongation at break of the modified starch (MS) reached 2070 %, and considerable ductility (>1000 %) as well as well-complexed structure were maintained after six months. Furthermore, the MS was able to undergo self-healing after fracture or a temperature-controlled stiffness transition. Moreover, it underwent complete degradation in soil within 30 d. Finally, an actuator was prepared by doping the MS with nano-Fe3O4 particles to realize a dual magnetic and optical response. Dynamic monitoring was also achieved based on the electrical signal, thereby demonstrating the broad application scope of this material in the development of biodegradable flexible actuators.

A novel starch‐based composite hydrogel enhanced by activated charcoal from the banana peel for water decontamination

AbstractThe efficient removal of potential toxic elements (PTEs) from aqueous systems is an important challenge in water purification and industrial effluent treatment. Starch‐based hydrogels have shown promise in this context due to their unique properties, such as high absorption capacity and water retention. This work synthesized a novel hydrogel with and without activated charcoal (AC) from banana peel (5 wt.%) and trisodium citrate as a crosslinking agent and starch to remove PTEs. These hydrogels were characterized by Fourier‐transformed infrared (FTIR), scanning electron microscopy, TGA, XRD, water absorption, and zero‐charge point techniques. Subsequently, the affinity of AC, neat hydrogel, and the composite hydrogel for removing Cr6+, Cd2+, Ni2+, Mn2+, Zn2+, and Cu2+ in aqueous solution was evaluated. FTIR confirmed a crosslinking reaction between the starch molecules and the crosslinking agent (trisodium citrate). Besides, the addition of hydrogel+5%AC altered the crosslinking process. Adding AC to the hydrogel composite increased crystallinity, thermal stability, and porous size. The highest removal efficiency of neat hydrogel and hydrogel+5%AC was for Cr6+, obtaining 83.2% and 98.5%, respectively. As for the AC, the removal of Cu2+ was satisfactory, with 80.4%. Thus, hydrogel+5%AC proves to be a highly viable adsorbent for posttreatment of wastewater due to its ability to efficiently remove PTEs.

A study on Effect of Ambient Air Pollution from Roadside Traffic on Qualitative and Quantitative Phytochemical Constituents of Solanum tuberosum L.

Solanum tuberosum L. is a useful vegetable crop and a member of the Solanaceae family that yields starch molecules with a high concentration. The analysis of both qualitative and quantitative phytochemical substances was the main focus of the current investigation. We have chosen places with road traffic and without road traffic (control) for the crop comparison analysis. The qualitative phytochemical substances analysed protein, carbohydrate, iodine, phenol, tannin, flavonoids, saponin, glycosides, steroids, terpene, and alkaloids. The complete phenolic content exhibits a total mean value of 0.03712, surpassing the threshold of 0.03176, while the overall flavonoid content shows a total mean value of 0.04696, exceeding the threshold of 0.03764. Crops growing close to busy road traffic had lower phytochemical substances, in terms of quantity and quality. This record demonstrates the detrimental impact of air pollution caused by vehicles on crop vegetation. Crop vegetation differs between control and road traffic sites, according to data on both qualitative and quantitative phytochemical substances.

Addition of Cyperus esculentus (tiger nut) milk improved the flavor and gelation properties of set yogurt: The main contribution of volatile constituents, starch and proteins

The modification effects of Cyperus esculentus milk (CEM) on the sensory and gel properties of set yogurt were elucidated in this study. It was found that a suitable CEM addition adjusted the color, moderated the acidity, and enriched the aroma of compound yogurt. Interestingly, the internal network structures of yogurt gel were strengthened at a low CEM addition, causing the improvement of yogurt textural properties, viscoelasticity and water-holding-capacity. However, a high CEM addition induced the incompact gel structures, unbeneficial to the expected textures and rheology of compound yogurt. Then, starch (CES) and proteins (CEP) were isolated to elucidate their influence on the gelation behaviors of casein. The results showed that CES always promoted the formation of CES-casein gel, improving its textural, elastic and morphological characters. This resulted from the presence of branchy side chains of amylopectin and the viscosity of starch molecules, making CES tightly anchor with casein gel and thus fill in the gel pores. However, the CEP-casein gel properties described an enhanced-weakened trend with CEP addition increasing. Notably, at a low addition, CEP well-dispersed and interacted with casein, filling into gel pores and thus strengthening gel network, while at a high addition, the self-gelling CEP gradually separated from casein gel due to few branchy structures and insufficient viscosity. It was the characteristic behaviors of CEM components that affected the gelling properties of compound yogurt. Conclusively, a moderate addition of CEM (<20%) is recommended to enrich the flavor of set yogurt with simultaneously-improved or maintained textural and gelling properties.

Structural elucidation and functional characteristics of novel potential prebiotics produced from Limosilactobacillus reuteri N1 GtfB-treated maize starches

The recently characterized Limosilactobacillus reuteri N1 GtfB (LrN1 GtfB) from glycoside hydrolase family 70 is a novel 4,6-α-glucanotransferase acting on starch/maltooligosaccharides with high enzyme activity and soluble protein yield (in heterogenous system). In this study, the influence of the treatment by LrN1 GtfB on the fine structure and functional characteristics of three maize starches were furtherly investigated and elucidated. Due to the treatment of LrN1 GtfB, the starch molecules were transformed into reuterans containing linear and branched (α1 → 6) linkages with notably smaller molecular weight and shorter chain length. Moreover, the (α1 → 6) linkage ratios in the GtfB-modified high-amylose maize starch (GHMS)/normal maize starch (GNMS)/waxy maize starch (GWMS) increased by 18.3 %/12.6 %/9.0 % as compared to their corresponding controls. In vitro digestibility experiment revealed that the resistant starch content of GHMS, GNMS and GWMS increased by 16 %, 18 % and 25 % as compared to the starch substrates. Furthermore, the butyric acid yielded from GHMS, GNMS and GWMS in the in vitro fermentation experiments were 1.4, 1.5 and 1.4 times higher than those of commercial galactose oligosaccharides. These results indicated that the highly-branched short-clustered reuteran synthesized by LrN1 GtfB might serve as novel potential prebiotics, and provide insights for the synthesis of promising prebiotic dietary fiber from starch.

Pasta Drying Defects as a Novel Ingredient for Hard Dough Biscuits: Effect of Drying Temperature and Granulation on Its Functionality.

Various drying temperatures impact the texture of pasta and cause different drying defects. These by-products could reflect techno-functional characteristics which are suitable for cereal products. This research addresses the influence of low (LT) and high (HT) drying pasta defects with two granulations on the theoretical and functional characteristics of hard dough biscuits. By shifting from a LT to HT drying temperature, a higher onset and peak temperature was found due to the higher mobility of starch molecules with increasing crystalline stability. The lowest transition enthalpy of biscuit formulation was also observed for higher incorporation of fine HT pasta regrinds. The algebraic model of dough with consistography determined the poor-extensible gluten and a high resistance with a greater value of P/L and P indices for LT regrinds. Scanning electron microscopy revealed a heavy and dense texture with immersed starch granules for additional fine regrinds while coarse samples caused swell granules with greater diameter. Moreover, fine HT regrinds reflected the lowest L* value for biscuit due to heat gradient tension with the hard milling process which leads to protein denaturation with decreasing nitrogenous.

Enzymatic modification lowers syneresis in corn starch gels during freeze–thaw cycles through 1,4-α-glucan branching enzyme

The current research in the food industry regarding enzymatic modification to enhance the freeze–thaw (FT) stability of starch is limited. The present study aimed to investigate the FT stability of normal corn starch (NCS) modified using 1,4-α-glucan branching enzyme (GBE) derived from Geobacillus thermoglucosidans STB02. Comprehensive analyses, including syneresis, scanning electron microscopy, and low-field nuclear magnetic resonance, collectively demonstrated the enhanced FT stability of GBE-modified corn starch (GT-NCS-30) in comparison to its native form. Its syneresis was 66.4 % lower than that of NCS after three FT cycles. Notably, GBE treatment induced changes in the pasting properties and thermal resistance of corn starch, while simultaneously enhancing the mechanical strength of the starch gel. Moreover, X-ray diffractograms and microstructural assessments of freeze–thawed gels indicated that GBE treatment effectively hindered the association of corn starch molecules, particularly amylose retrogradation. The enhanced FT stability of GBE-modified starch can be attributed to alterations in the starch structure induced by GBE. This investigation establishes a foundation for further exploration into the influence of GBE treatment on the FT stability of starch and provides a theoretical basis for further research in this area.

Analysis of the mechanism of resistance to enzymatic hydrolysis of RS-5 resistant starch

RS-5 refers to the resistant starch formed by complexation of starch molecules with other molecules. In this study, the molecular mechanism of RS-5 was analysed. First, it was found, when α-amylase acted on the starch-lipid complexes, the glucose residues involved in complexation cannot be hydrolyzed by α-amylase, while the glucose residues not directly involved in complexation can be hydrolyzed. Second, lipid molecules are not necessary for the formation of RS-5 and can be replaced with small peptides or decanal molecules. Considering the multiple health hazards that may result from excessive lipid intake, small peptides composed of essential amino acids may be more desirable materials for RS-5 preparation. Third, starch-lipid complexes had strong interactions with α-amylase, which provides evidence in support of the sliding continuum hydrolysis hypothesis of α-amylase. These results revealed the mechanism of RS-5 at the molecular level, which provides a reference for the production and research of RS-5.

Insight into the multi-scale structure and retrogradation of corn starch by partial gelatinization synergizing with epicatechin/epigallocatechin gallate

Starch retrogradation is of great importance to the quality of starch-based food. This study investigated the effect of partial gelatinization (PG) synergizing with polyphenol (epicatechin, EC; epigallocatechin gallate, EGCG) on the multi-scale structure and short/long-term retrogradation of corn starch (CS). The PG synergizing with EC/EGCG substantially suppressed the short/long-term retrogradation properties of CS. These could be confirmed by the decreased storage modulus and viscosity, the relative crystallinity (1.54%, 3.56%), and the retrogradation degree (9.99%, 20.18%) of CS during storage for 1, 14 days after PG synergizing with EGCG and EC, respectively. This is because PG treatment promoted the hydrogen bond interaction between disordered starch molecules and EC/EGCG. These were proven by the larger aggregation, more and brighter fluorescents, and the reduced long/short-range order structures in CS after PG synergizing with EC/EGCG. This study is helpful for the development of foods with enhanced nutrition and low-retrogradation.

Enhancing the nonlinear rheological property and digestibility of mung bean flour gels using controlled microwave treatments: Effect of starch debranching and protein denaturation

In this study, we examined the possibility of using industrial microwave processing to enhance the gelling properties and reduce the starch digestibility of mung bean flour (MBF). MBF (12.6 % moisture) was microwaved at a power of 6 W/g to different final temperatures (100–130 °C), and then its structural and functional properties were characterized. The microwave treatment had little impact on the crystalline structure or amylose content of the starch, but it roughened the starch granule surfaces and decreased the short-range ordered structure and degree of branching. In addition, the extent of mung bean protein denaturation caused by the microwave treatment depended on the final temperature. Slightly denaturing the proteins (100 °C) did not affect the nature of the gels (protein phase dispersed in a starch phase) but the gel network became more compact. Moderately denaturing the proteins (110–120 °C) led to more compact and homogeneous starch-protein double network gels. Excessive protein denaturation (130 °C) caused the gel structure to become more heterogeneous. As a result, the facilitated tangles between starch chains by more linear starch molecules after debranching, and the protein network produced by moderate protein denaturation led to the formation of stronger gel and the improvement of plasticity during large deformation (large amplitude oscillatory shear-LAOS). Starch recrystallization, lipid complexion, and protein network retard starch digestion in the MBF gels. In conclusion, an industrial microwave treatment improved the gelling and digestive properties of MBF, and Lissajous curve has good adaptability in characterizing the viscoelasticity of gels under large deformations.

Investigating the impact of boiling and pressure cooking on resistant starch levels in food

SummaryResistant starch (RS) has been shown to manipulate food digestion and nutrient metabolism as well as being important in promoting gut health. However, the presence of RS varies across diverse food systems depending upon process conditions. To investigate this, chickpeas, potatoes, arrowroots, unripe bananas and oats were subjected to boiling and pressure cooking at various cooking durations and the RS% was determined. After 45 min of boiling and 15 min of pressure cooking, RS% of chickpeas increased by ~29% and ~41%, respectively. Increasing the cooking time, together with boiling and pressure cooking, led to higher RS% in chickpeas, mainly due to the retrogradation of starch after gelatinisation. In contrast, boiling and pressure cooking led to a reduction in RS% for potatoes, arrowroots, unripe bananas and oats, while a further decrease was encountered with the increase in processing time. After 45 min of boiling, RS% of potatoes, arrowroots, unripe bananas, and oats were reduced by 58%, 22%, 80% and 70%, respectively. After 15 min of pressure cooking, RS% of potatoes, arrowroots and unripe bananas were reduced by 41%, 22% and 83%, respectively. This was mainly due to the disruption of the ordered structure of starch molecules during thermal processing in the presence of water. This study clearly elucidates the impact of boiling and pressure cooking on RS% as a function of processing time and type of RS source.

Starch digestibility: How single, double, and multiple physicochemical modifications change nutritional attributes of starch?

AbstractThe ever‐increasing ranges of starch applications have been restricted by some of its inherent adverse characteristics like retrogradability, gel opacity, low resistibility to variations of pH, and elevated shear/temperatures. Starch modification through various physical, chemical, and enzymatic methods has been proposed as the most mature platform to tackle such drawbacks. Along with their outstanding potential in enhancing the starch's technofunctional characteristics, physicochemical modifications could remarkably customize starch nutritional/digestibility attributes. For instance, physical modifications could remarkably change starch digestibility by manipulating the granular architecture while chemical approaches change it by altering the chemical structure of starch molecules, making them unrecognizable to digestive enzymes. Such alterations could even be more challenging upon applying a combination of starch modifications. The changes in starch digestibility through its modification via single, double, and multiple modifications have been overviewed in this review.

Analysis of the interaction between double-helix starch molecule and α-amylase

Diabetes is a major chronic disease that jeopardises human health. Resistant starch (RS) is important in controlling diabetes. However, the specific relationship between the starch crystalline structure and RS content needs to be further elucidated. In this study, the details of the interactions between different starch molecules (single-amylose and double-helix) and α-amylase were analysed using molecular docking and dynamic simulations. Single-amylose molecules could penetrate deep into the active groove of α-amylase and make full contact with the catalytic triad, and their G3 and G4 glucose residues were firmly bound to the bottom of the active groove throughout the simulation. However, the double-helix molecule in the crystalline region of starch could not fully penetrate to the bottom of the active groove and make full contact with the catalytic triad of α-amylase. This suggests that, without considering other structural factors, the RS content should be positively correlated with relative crystallinity. In addition, starch molecules had strong interactions with α-amylase (approximately 78 kJ/mol) and could form many hydrogen bonds with the amino acid residues of α-amylase such as Thr163, Gln63, and Ile148, which supports the sliding continuum hydrolysis hypothesis of α-amylase. These results explain the intrinsic relationship between the starch hydrolysis efficiency and crystalline structure at the molecular level and provide an important reference for the preparation of RS and elucidation of its mechanism.

Effect of two different Flammulina velutipes polysaccharides on the physicochemical and digestive properties of rice starch and their interaction mechanisms

This study investigated the interaction mechanisms between rice starch (RS) and two different Flammulina velutipes polysaccharides (FPs) obtained through water-extracted (WEFP) and alkali-extracted (AEFP) methods regarding the pasting, gelatinization, retrogradation, and in vitro digestive properties. The WEFP, with a majority of α-glucan and lower MW, and the AEFP, a high MW trihelix β-glucan, distinctly affected the physicochemical and digestive properties of RS in a dose-dependent manner. Both FPs reduced the leached amylose content, retrogradation, and digestibility of RS, and increased the shear stress, storage modulus, and loss modulus of RS. The swelling power and pasting viscosities of RS were inhibited by WEFP and enhanced with AEFP. Compared with the control RS gel, WEFP increased the gelatinization temperatures while AEFP accelerated the gelatinization of RS. Fourier-transform infrared analysis revealed WEFP enhanced the hydrogen bonding with starch and water molecules which increased the short-range ordered structures, and a more compact, wrinkle, and ordered network structures could be visualized in RS-WEFP gel, which attributed to the decreased glycemic responses of RS-WEFP gels. However, reduced hydrogen bonds were observed in RS-AEFP systems, and entanglement effect of viscous AEFP on starch granules resulted a thicker and more disordered RS-AEFP gel structure, which was the main factor restricted the digestion rates of RS. This study provides a theoretical insight about the application of FPs on RS-based hypoglycemic foods.

Fabrication and Characterization of Non-Conventional Starch Based Biofilms Employing Different Plasticizers

Increasing stress on environmental awareness has promoted the use of alternative strategies for common petrochemical based plastic sources to environmentally friendly biofilms and packaging materials. Food by products and underutilised indigenous plants sources are rich in biopolymers which can naturally decompose. The present study focusses on preparations of bioplastics from unconventional starch sources of litchi seed and churkha tuber as novel initiative to combat environmental pollution along with valorisation of undervalued plant sources and agrobased wastes. Ternary blend films of poly vinyl alcohol, starch, plasticizers like (glycerol, sorbitol, mannitol, propylene glycol, polyethylene glycol), citric acid prepared by casting technique produced best result. Comparative study of test samples (TH11, TH12, TH13, TH14 etc) with standardized thin films (TH1, TH2, TH3 etc.) showed variation in appearance, water activity, thickness, since the starch differ in their compositions, gelatinization and gelation time and temperature. High amylose containing litchi seed starch forms firm and more flexible films in comparison to low amylose containing churkha tuber starch. Maximum hygroscopicity was recorded in case of TH1 (77.4%) while thickness was maximum in case of TH12 (0.18 mm). Micro structural analysis clearly showed the nature of crosslinking between starch molecule and different plasticizers. The sensory analysis of food packed with the best among the formularized thin films showed mild change in taste while the other parameters remain same as normal. Better acceptability was in case of TH12 wrapped food rather than TH1. Thus, fabrication of biodegradable packaging is considered as the most sustainable alternative for food preservation. Int. J. Appl. Sci. Biotechnol. Vol 12(1): 29-38.

Enhanced starch accumulation in Chlorella sorokiniana as sugar platform and the expression profiling of key regulatory proteins

Microalgae can accumulate considerable starch as a renewable sugar platform for biofuel production. In this study, Chlorella sorokiniana exhibited a significant increase in starch content from 3.0% to 49.5% DM under sulfur limitation (SL) conditions, and the lower the concentration of sulfur was, the more effective it was. Direct enzymatic hydrolysis of wet biomass resulted in a glucose yield of 97.1%, indicating its potential for fermentable sugar production. However, C. sorokiniana grew slowly, and cell division and biomass accumulation decreased under SL conditions, which could be explained by the decreased photosynthetic efficiency and protein content. The sulfur replenishment (SR) confirmed the rapid response of C. sorokiniana in starch accumulation to sulfur availability. Thus, we further investigated the expression profiling of key regulatory proteins under Control-SL-SR stages. The expression of AGPase A was strongly induced in the SL stage and subsequently downregulated during SR stage, suggesting its role as a key regulatory protein for enhanced starch accumulation. Additionally, downregulation of SBE and GBE expression likely contributed to structural modifications of the starch molecules. These proteins could serve as potential targets for metabolic engineering in further improving the starch production capacity in C. sorokiniana.

The physicochemical and in vitro digestion characteristics of Cynanchum auriculatum Royle ex Wight starch‐tea polyphenols non‐inclusive complex

SummaryThe effect of tea polyphenols (TP) on the physicochemical, structural and digestive properties of Cynanchum auriculatum Royle ex Wight starch (C. auriculatum starch) was studied. Scanning electron microscopy analysis showed that a looser and more porous structure was observed in C. auriculatum starch‐TP. Rheological results revealed that G′ and G″ of C. auriculatum starch were decreased with TP addition. X‐ray diffraction pattern showed TP could inhibit the relative crystallinity structure of C. auriculatum starch, thereby delaying the retrogradation of starch. Fourier‐transform infrared analysis confirmed that TP and C. auriculatum starch molecules formed non‐inclusive complexes through hydrogen bonding interaction. Moreover, TP could reduce the digestibility of the gelatinised C. auriculatum starch. These findings provide a theoretical information on C. auriculatum starch as a functional ingredient for regulating the postprandial glycemic response of starchy foods.