Yuxiang Bai

• PhD
• Jiangnan University

A new super-branched amylopectin with longer exterior chains was produced from normal maize starch by modification with branching enzyme followed by 4-α-glucanotransferase, and applied for co-entrapment of a curcumin-loaded emulsion in alginate beads. The network structure of the gel beads was obtained with Ca 2+-cross-linked alginate and a modest...

Maltogenic α-amylase (MA) is widely used to modify starch for improving properties. In this work, A- and B-type starches were separated from wheat completely and submitted to MA hydrolysis. Firstly, research in morphological features (SEM) suggested that MA treatment did not destroy the granule integrity. Next, crystalline features from XRD and SAX...

Hydrolysis of highly concentrated soluble starch (60%, w/w) was performed using sequential α-amylases from Bacillus stearothermophilus (T, 0.2%, w/w) and Bacillus amyloliquefaciens (B, 0.1%, w/w) to identify their possible action patterns. We found that T reduced the average molecular weight (Mw) of soluble starch from 52,827 Da to 31,914 Da and si...

Maltogenic α-amylase (MA) are commercially used in the baking industry to retard starch retrogradation. However, whether MA can be used to modify rice flour during the fermentation process to improve the quality of rice flour remains unclear. In this study, MA was introduced during rice cake (RC) processing, and the modification effect and underlyi...

Limosilactobacillus reuteri 121 4,6-α-glucanotransferase (GtfBΔN) modifies starch by cleaving (α1 → 4) linkages and introducing non-branched (α1 → 6) linkages to produce functional starch derivatives. Research has mainly focused on GtfBΔN converting amylose (linear substrate), whereas the conversion of amylopectin (branched substrate) has not been...

Rice flour (RF) has become a promising food material. In the present study, RF with higher protein content was prepared using a granular starch hydrolyzing enzyme (GSHE). Particle size, morphology, crystallinity, and molecular structures of RF and rice starch (RS) were characterized to establish a hydrolytic mechanism; thermal, pasting, and rheolog...

Modification of starch by transglycosylases from glycoside hydrolase families has attracted much attention recently; these enzymes can produce starch derivatives with novel properties, i.e. processability and functionality, employing highly efficient and safe methods. Starch-active transglycosylases cleave starches and transfer linear fragments to...

How to improve the solubility of linear dextrins (LD) and retain their characteristic helix amphiphilic cavities with flexible embedding capability, is a question worth exploring without adding new chemical groups. The strategy presented in this study is to attach a highly flexible (α-1 → 6) glucochain at the reducing end of LD by preparing a new t...

Highly branched α-glucan (HBAG) proved to be a promising material as an osmotic agent in peritoneal dialysis solutions. However, high resistance of HBAG to amylolytic enzymes might be a potential drawback for peritoneal dialysis due to its high degree of branching (20-30 %). To address this issue, we designed a small-clustered α-glucan (SCAG) with...

Isomalto/malto-polysaccharides (IMMPs) derived from malto-oligosaccharides such as maltoheptaose (G7) are elongated non-branched gluco-oligosaccharides produced by 4,6-α-glucanotransferase (GtfB). However, G7 is expensive and cumbersome to produce commercially. In this study, a cost-effective enzymatic process for IMMPs synthesis is developed that...

A broad range of enzymes are used to modify starch for various applications. Here, a thermophilic 4-α-glucanotransferase from Thermoproteus uzoniensis (TuαGT) is engineered by N-terminal fusion of the starch binding domains (SBDs) of carbohydrate binding module family 20 (CBM20) to enhance its affinity for granular starch. The SBDs are N-terminal t...

Oligosaccharides derived from agar, that is, agarooligosaccharides and neoagarooligosaccharides, have demonstrated various kinds of bioactivities which have been utilized in a variety of fields. Enzymatic hydrolysis is a feasible approach that principally allows for obtaining specific agar oligosaccharides in a sustainable way at an industrial scal...

An increase in the number of antibiotic resistance genes burdens the environment and affects human health. Additionally, people have developed a cautious attitude toward chemical preservatives. This attitude has promoted the search for new natural antimicrobial substances. Oligosaccharides from various sources have been studied for their antimicrob...

Malto-oligosaccharides (MOS) are α-1,4 glycosidic linked linear oligosaccharides of glucose, which have a diverse range of functional applications in the food, pharmaceutical, and other industries. They can be used to modify the physicochemical properties of foods thereby improving their quality attributes, or they can be included as prebiotics to...

The aim of this study was to continuously hydrolyze mango peel pectin, an agricultural waste, into pectic oligosaccharides (POS) with antibacterial activity. A packed-bed reactor (PBR) with immobilized polygalacturonase was designed, and the effects of the process conditions (flow rate, substrate concentration, and enzyme amount) were evaluated. Th...

Solid-liquid thermo-reversibility, lacking in raw starch is an important property for gels allowing repeated thermal processing in food. In this work, the Thermoproteus uzoniensis 4-α-glucanotransferase (TuαGT) was used to modify five different starches from potato, corn, rice, wheat, and pea and the thermo-reversibility of the modified starch gels...

Although different types of starch have been modified with maltogenic α‐amylase (MGA), its behaviour on waxy rice starch (WRS) remains obscure. This study aimed to modify cooked WRS with high concentration using MGA. The molecular weight of WRS decreased from 1.8 × 10⁷ to 4.1 × 10⁶ Da due to the exo–endo activity of MGA, while a high proportion of...

Glycogen-like glucan (GnG) is a unique hyperbranched polysaccharide nanoparticle which is drawing increasing attention due to its biodegradability and abundant short branches that can be functionalized. Because starch and GnG are both composed of glucose residues and have similar glucosidic bonds, GnG could be fabricated by sucrose phosphorylase, α...

Isomalto/malto-polysaccharides (IMMPs) with degree of polymerization (DP) 10–100 have novel potential applications, including enhanced solubility and anti-inflammatory. However, there are minimal synthetic methods for preparing IMMPs with a relatively higher DP, which is due to the lack of suitable molecular weight linear dextrins (I-LDs). The exis...

4-α-glucanotransferase is used to produce thermoreversible starch gels to alleviate limitations to use of starch gels in repetitively heat-processed foods. However, the gel strength was weakened after this enzyme modification. In the present study, treatment by amylosucrase (NpAS) of corn starch and sucrose was applied to retain the gel thermorever...

Considering the weak gel of tapioca starch and generally incomplete gel-advancing mechanism of α-amylase modification, two commercial α-amylases (named A- and N-amylase) with different reaction patterns were used to improve the gel strength of cross-linked tapioca starch. SEM showed that A-amylase exhibited surface erosion pattern, compared to an e...

Cyclodextrins (CDs) are yielded by cyclodextrin glycosyltransferase (CGTase) using starches or their derivatives as substrates. However, how starch fine structure affects it production is still ambiguous. This study aimed to decipher the relevance between the external chain length (ECL) and CD production. The waxy maize starch was hydrolyzed by β-a...

High substrate viscosity during the production process suppressed the formation of gamma-cyclodextrin (γ-CD) from starch. Although liquefaction can be carried out by enzymes with high temperature optimum, some CGTases of interest are not suitable due to loss of activity at the gelatinization temperature. In order to apply a gamma-cyclodextrin gluco...

By heterologous expression of a gene from Palaeococcus ferrophilus, a novel recombinant enzyme designated AMPf was obtained and proved to be an amylolytic enzyme with unique catalytic characteristics. The optimal temperature and pH of AMPf were 50 °C and 7.0 respectively. Although sequence analysis and acarbose hydrolysis ability indicated that AMP...

Enzymatic modification is an effective method to inhibit starch retrogradation. However, lack of quantification of relationships between enzymatic modification and starch retrogradation makes the enzymatic improvement unpredictable. In this study, maltogenic α-amylase (MA) was used to treat wheat starch granules to restrain retrogradation, aiming t...

The quality characteristics of rice-based products depend on the properties of their starch component. Maltogenic α-amylase (MA) is extensively used as an anti-staling agent in bakery foods. To expand its application in rice-based products, in the current study, normal rice starch (NRS) was subjected to MA. The enzyme susceptibility of NRS and the...

Diabetes is considered one of the biggest health crises in 21st century. Controlling carbohydrate digestibility by inhibiting starch digestive enzyme (α-amylase and α-glucosidase) activities is an efficient strategy to control postprandial hyperglycemia. Over the last decade, synthetic inhibitors are most effective pharmaceutical approach for the m...

To improve starch processing as well as enrich the enzyme resources, an amylopullulanase (CEApu) from Caldisericum exile was heterologously expressed and characterized. CEApu was identified as a glycoside hydrolase from glycoside hydrolase (GH) family 57. The optimal temperature and optimal pH were determined to be 75 °C, and pH 5.5 and 8.5, respec...

Cyclodextrinase (CDase) and cyclodextrin glucosyltransferase (CGTase) were synergistically used to provide a novel enzymatic method in lowing in vitro digestibility of waxy maize starch. The molecular structure, malto-oligosaccharide composition, and digestibility properties of the generated products were investigated. The molecular weight was redu...

Carbohydrates, which are mostly present in sugar, starch, and fiber, are one of the main ingredients of food and the primary source of energy in the human diet. Among these three main sources, starch stands out as one of the most abundant reserves of carbohydrates. Investigating starch would not only enhance our understanding of the functionality o...

The inhibitory effect of β-CD on pullulanase which hydrolyzes α-1,6 glycosidic bond in starch to release more available linear substrates, limited substrate utilization thus influencing the yield of β-CD. Here, an aspartic acid residue (D465) which interacted with cyclodextrin ligand by hydrogen bond, was mutated to explore its contribution to bind...

A resistance effect between retrograded starch and iodine and its potential use for evaluating retrograda-tion properties of rice starch were investigated in this study. Our results showed that the resistance effect obviously occurred during the interaction of retrograded starch and iodine ions. The extent of the resistance was selected as a parame...

Ginkgo biloba was a popular phytomedicine as the essential ingredient of many food supplement. In this work, a bio-inspired HPTLC method was proposed for the visualized screening of nifedipine adulteration in food supplement based on Gingko biloba. To customize the visualization of the analyte by inhibiting bacterium (Photobacterium phosphoreum) bi...

Gelation of starch is a process during short-term retrogradation. However, the long-term retrogradation always leads to the quality deterioration of starch-based food. In this work, a new type of modified tapioca starch (MTS) gel with maintained starch short-term gelation strength and retarded long-term retrogradation was prepared using a novel rec...

This work investigated the interaction between cyclodextrins and pullulanase to provide insight into the production and application of cyclodextrins. Enzyme activity and kinetic assays showed that α-cyclodextrin (α-CD), β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) inhibited pullulanase in a competitive manner. Circular dichroism spectra and fluo...

A novel cyclodextrin (CD)-based controlled release system was developed in the small intestine to control the rate of drug release, on the premise of enteric-coated tablets. The system was designed based on the enzymes exogenous β-cyclodextrin glycosyltransferase (β-CGTase) and endogenous maltase-glucoamylase (MG), wherein MG is secreted in the sma...

Enzymatic modification is generally applied to enhance desirable attributes of starch. In this study, β-cyclodextrin glycosyltransferase (β-CGTase) together with a specific cyclodextrinase (CDase) was used to modify corn starch. For single β-CGTase treatment, the molecular weight (Mw) was reduced to 36.7 × 10⁵ g/mol and 7.7 × 10⁵ g/mol for 1 h and...

Since β-cyclodextrin (β-CD) was the competitive inhibitor of pullulanase, substrate utilization and product inhibition were a conflict in β-CD production when using pullulanase for debranching to release more convertible substrate. Here, a phenylalanine complexed with cyclodextrin ligand via classic hydrophobic interaction and hydrogen bond in the...

The production of γ‐cyclodextrin usually includes the utilization of organic complexants. However, the non‐complexant production of γ‐cyclodextrin is always being explored due to the defects of organic complexants. However, in non‐complexant production, the separation of γ‐cyclodextrin from α‐ and β‐cyclodextrin is still a challenge. Here, the sele...

Glucosyl‐β‐cyclodextrin (G1‐β‐CD) has wide application prospects in the food, pharmaceutical, agriculture, and chemical industry as its better solubility and biocompatibility than parent β‐cyclodextrin (β‐CD). However, researches on G1‐β‐CD were few due to difficulties in its preparation and separation. In the present study, a one‐pot method was as...

An open reading frame from Palaeococcus pacificus was discovered by genomic analysis. The recombinant PpCD was proved as novel extremely thermal-stable cyclodextrinase with potential on production of malto-oligosaccharides with specific degree of polymerization. This enzyme has extremely high substrate specificity toward cyclodextrins, while the ra...

Pullulanase, a typical debranching enzyme, specifically hydrolyzes α-1,6 glycosidic linkages in pullulan, starch and so on. There is accumulated knowledge about the catalysis of pullulanase, but functional roles of acceptor subsites get less attention. According to the crystal structure of pullulanase from Bacillus subtilis str. 168, stacking inter...

This paper proposes a facile and specific method tailored for quantifying and confirming folic acid in food, based on the combination of high-performance thin layer chromatography with fluorescence densitometry and surface-enhanced Raman spectroscopy. Chromatography was carried out on silica gel plates, using methanol/ethyl acetate/ammonia (6:4:1,...

A novel cyclodextrin-functionalized hybrid silicon nano-adsorbent material (6-EA-β-CD-Si) was synthesized via the nucleophilic substitution method. The structure was detected by Fourier transform infrared (FT-IR), X-ray, thermogravimetric analysis, and Brunauer-Emmett-Teller (BET) analysis. Results reveal that the BET surface area of 6-EA-β-CD-Si i...

In this study, a novel recombinant amylosucrase from Truepera radiovictrix DSM 17093 was characterized and found to produce α-glucans from sucrose. The enzyme showed maximum total and transglucosylation activities at pH 7.5 and maximum hydrolysis activity at pH 5.5. The optimum temperature for total, transglucosylation, and hydrolysis activities we...

Levan, a versatile fructan, possesses promising prospects for application in the food and pharmaceutical industries and in many other fields due to the superior physicochemical properties and physiological functions of this fructan. In this study, a thermostable levansucrase was identified from Lactobacillus reuteri LTH5448. This enzyme shared high...

Few reports about the biosynthesis of α-arbutin using amylosucrase are available. In this work, an amylosucrase from Cellulomonas carboniz T26, CcAS, was identified for highly efficient synthesis of α-arbutin using 20 mM sucrose and 5 mM hydroquinone as a glucosyl donor and acceptor, respectively. The optimum conditions for transglucosylation are a...

In comparison with natural α- and β-cyclodextrin (CD), γ-CD has attracted much attention due to their large hydrophobic cavities, high water solubility, and bioavailability. However, the production of γ-CD is still rather expensive and time-consuming. To overcome the high cost and long induction time, pUC119 was selected as the gene expression vect...

A high molecular weight levan was produced by a novel levansucrase and some properties of this polymer were investigated. The levan exhibited a poroid microstructure as well as series of individual ellipsoidal or spheroidal particles. The weight-average molecular weight (M¯w) of the levan was determined to be 1.41×10(8)Da. In a 0.1% solution, the l...

Inulin is composed of fructose residues connected by β-(2, 1) glycosidic linkages with many promising physiochemical and physiological properties. In this study, an inulin-producing inulosucrase gene from Lactobacillus gasseri DSM 20604 was cloned, expressed and purified. SDS-PAGE and gel filtration found that the recombinant inulosucrase is a mono...

By using cyclodextrin (α-CD) self-assembly into a hydrogel with the triblock copolymer Pluronic F127, nanomicrocrystalline cellulose was introduced into a gel system to form a composite CNC-β-CD/α-CD/Pluronic F127 hydrogel (CCH). CCH was modified further by grafting acrylic acid to form a novel acrylated composite hydrogel (ACH). The swelling degre...

Crystal structure of the first representative of the GH70 4,6-α-glucanotransferase subfamily, showing overall structure and the main features that distinguishes it from α-amylases of GH13 and glucansucrases of GH70. Reference PDBs : 5JBD (native), 5JBF (complex with maltopentaose). See also Crystal Structure of 4,6-α-Glucanotransferase Supports Die...

Instead of β-cyclodextrin (β-CD), branched β-CDs have been increasingly used in many aspects as they possess better solubility and higher bioadaptability. But most commercialized branched β-CDs were chemically synthesized. Thus, the glucosyl-β-cyclodextrin (G1-β-CD) prepared via enzymatic approach could be a nice substitute. However, the yield of G...

Lactic acid bacteria (LAB) produce α-glucans, using glucansucrases (GSs) from glycoside hydrolase family 70 (GH70), from sucrose. It was proposed that GSs are evolutionarily linked to GH13 enzymes acting on starch-like substrates. Recently, a GH70 subfamily was discovered containing 4,6-α-glucanotransferases (4,6-α-GTs) from Lactobacilli, synthesiz...

Amylosucrase, catalyzing the synthesis of α-(1, 4)-glucan from sucrose, has been widely studied and used in carbohydrate biotransformation because of its versatile activities. In this study, a novel amylosucrase was characterized from Cellulomonas carbonis T26. The recombinant enzyme was overexpressed in Escherchia coli and purified by nickel affin...

Food processing and refining has dramatically changed the human diet, but little is known about whether this affected the evolution of enzymes in human microbiota. We present evidence that glycoside hydrolase family 70 (GH70) glucansucrases from lactobacilli, synthesizing α-glucan-type extracellular polysaccharides from sucrose, likely evolved from...

The human diet has been subject to dramatic changes due to food processing and refining. however, whether this affected the evolution of enzymes in human microbiota is largely unknown. It was proposed that glycoside hdyrolase family 70 (GH70) glucansucrases (GS) from Lactobacilli, which synthesize α-glucan type extracellular polysaccharides (EPS) f...

Lactic acid bacteria (LAB) are known to produce large amounts of α-glucan exopolysaccharides. Family GH70 glucansucrase (GS) enzymes catalyze the synthesis of these α-glucans from sucrose. The elucidation of the crystal structures of representative GS enzymes has advanced our understanding of their reaction mechanism, especially structural features...

Exopolysaccharides (EPS) of lactic acid bacteria (LAB) are of interest for food applications. LAB are well-known to produce α-glucan from sucrose by extracellular glucansucrases. Various Lactobacillus reuteri strains also possess 4,6-α-glucanotransferase (4,6-α-GTase) enzymes. Purified 4,6-α-GTases (e.g. GtfB) were shown to act on starches (hydroly...

4,6-α-Glucanotransferase (4,6-α-GTase) enzymes, such as GTFB and GTFW of Lactobacillus reuteri strains, constitute a new reaction specificity in Glycoside Hydrolase Family 70 (GH70) and are novel enzymes that convert starch or starch hydrolysates into isomalto/malto-polysaccharides (IMMPs). These IMMPs still have linear chains with some α1→4 linkag...

The GTFB enzyme of the probiotic bacterium Lactobacillus reuteri 121 is a 4,6-α-glucanotransferase of glycoside hydrolase family 70 (GH70; http://www.cazy.org ). Contrary to the glucansucrases in GH70, GTFB is unable to use sucrose as substrate, but instead converts malto-oligosaccharides and starch into isomalto-/malto- polymers that may find appl...

In this article, 62−α-maltotriosyl-maltotriose was consecutively prepared by hydrolysis and reverse synthesis action of Bacillus Acidopullulyticus pullulanase using pullulan as a substrate. Maltotriose syrup was obtained by hydrolyzing of pullulan with pullulanase. The optimal reverse synthesis conditions were then investigated and the optimum cond...

In this study, a glucose oxidase (GOX), papain and xylanase combination was developed for fresh whole wheat dough for both browning inhibition and rheological improvement. Measurements of carotenoids extracted from enzyme-treated doughs showed that 0.001% (w/w) GOX could catalyze the oxidization of 40.0% carotenoids and thus cause a decrease of bro...

Amylomaize (AMM) was utilized as the substrate for cycloamylose (CA) production in this study. After debranching, AMM was incubated with 10 U/g of Thermus aquaticus 4-α-glucanotransferase (TA 4αGTase) for various reaction times in water or in DMSO reaction system. The maximum conversion yield of CA was greatly improved from 24.55% to 45.58% and fro...

The dissolution and digestion characteristics of maize starch processed with a combination of α-amylase and pullulanase (ERS) were investigated. The results were compared with those of high pressure-processed RS (HRS) and regular maize starch. The ERS exhibited a considerably lower dissolution and digestibility than the HRS under conditions that si...

In this study, a novel high hydrostatic pressure (HHP) technique was used to prepare the β-cyclodextrin-vitamin C (β-CD-Vc) inclusion complex. The inclusion ratio was positively correlated with the pressure under 300 MPa and remained at above 50.0% when the pressure was more than 300 MPa. Fourier-transform infrared spectroscopy (FI-IR) and UV-visib...

a b s t r a c t An approach mainly based on thermogravimetric analysis (TGA) was developed to evaluate the stoichiometric ratio (SR, guest to host) of the guest–-cyclodextrin (Guest--CD) inclusion complexes (4-cresol--CD, benzyl alcohol--CD, ferrocene--CD and decanoic acid--CD). The present data obtained from Fourier transform-infrared (FT-IR) spec...

In our current research work, we investigated the effects of molecular weight (M w) and the concentration of dextran presence during cane sugar manufacturing on the rheological and glass transition properties of supersaturated sucrose solution. Three dextrans of various M w, namely 100,000 g/mol (T 100), 500,000 g/mol (T 500) and 2,000,000 g/mol (T...

Physico-chemical properties of rice starch gels prepared by microwave, ultrasonic–microwave synergistic and conventional heat treatments were investigated in this study. The results showed that the gel firmness and the hydrolysis degree of non-waxy rice starch gels obtained from microwave heat (75.3±3.8g, 60.8±1.7%) and ultrasonic–microwave synergi...

Retrogradation process of pressure-gelatinized rice starches was investigated and compared with the heat-gelatinized ones in this study. Our results showed that the retrogradation rate of normal rice starch gelatinized by high hydrostatic pressure (HHP) was slower than that by heat. Nevertheless, there was no difference in retrogradation rate for w...

Response surface methodology (RSM) was used to study the effects of screw speed, feed rate, feed moisture content, and terminal barrel temperature on several system parameters (product temperature, die pressure, motor torque, specific mechanical energy and product moisture content) and physical properties (expansion ratio) of the reformed rice made...

A resistance effect between retrograded starch and iodine and its potential use for evaluating retrogradation properties of rice starch were investigated in this study. Our results showed that the resistance effect obviously occurred during the interaction of retrograded starch and iodine ions. The extent of the resistance was selected as a paramet...

The major garlic oil (GO) components were encapsulated by hydroxypropyl β-cyclodextrin (HP-β-CD), and their encapsulation properties were compared in this study. Our results showed that the optimal conditions for the GO encapsulation were as follows: weigh ratio at 12:88 (GO: HP-β-CD), pH at 5.0, and inclusion time at 4 h. Furthermore, results from...