Effect of Pullulanase Debranching Time Combined with Autoclaving on the Structural, Physicochemical Properties, and In Vitro Digestibility of Purple Sweet Potato Starch

Enzymatic Debranching of Starch: Techniques for Improving Drug Delivery and Industrial Applications

Starch is a biomacromolecule comprising glucose units linked together and is one of the most widely sourced biomacromolecules from plants because of its easy availability and versatility. However, high water solubility and rapid degradation restrict the application of starch in some areas, such as drug delivery. This review describes an enzymatic debranching methodology for enhancing the properties of starch and for improving its performance in both drug delivery applications and various industrial uses. Enzymatic debranching, with enzymes such as pullulanase and isoamylase, targets the branching points in starch chain parts. The enzymes cleave the internal covalent bonds within amylopectin branches. The final product of the reaction is a linear short‐chain glucan. As a result of the enzymatic debranching reaction, large changes in digestibility and molecular weight are observed; the degree of branching decreases; the solubility is modified; viscosity characteristics are affected; and gelatinization is also affected. These changes make debranched starch suitable for use in various types of drug delivery systems, such as sustained release formulations and targeted delivery systems. By properly controlling both the debranching time and the treatment conditions, the desired properties of modified starch can be achieved. Enzymatically debranched starch is used in the food industry for enhanced textural and stabilizing properties and in the paper and textile industries to increase strength and viscosity. In addition, debranched starch can be used as a biodegradable packaging material and as a renewable source in biofuels. This review discusses recent developments concerning the enzymatic debranching of starch, describes the enzymes and techniques applied, their effects on the structure and properties of the starch obtained, and the value chain applications tested. This study provides a clear overview of how enzymatically debranched starch can play a role in the innovation of drug delivery systems and various industrial processes.

Microencapsulation of cornmint oil with octenyl succinate anhydride debranched starch by electrostatic spray drying: Characterization and release kinetics of the aroma components

In this study, a novel method for the preparation of corn mint oil microcapsules was developed using electrostatic spray drying (ESD) with three octenyl succinate anhydride debranched starch (OSADS) wall materials. It was complexed with gum arabic (GA) and maltodextrin (MD). This study addresses the research gap that traditional methods have low efficiency in encapsulating volatile compounds (such as essential oils). The control group used ordinary spray drying (OSD) and untreated starch wall material. After debranching, OSADS exhibits reduced solubility and viscosity, enabling the encapsulation of more aromatic compounds. The loading of the microcapsules ranged from 50.26 % to 73.28 %, indicating that the encapsulation efficiency was significantly improved using OSADS compared to traditional methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed spherical core-shell structures and multicapsule structures. The slow-release process of cornmint oil was efficiently monitored in real-time using transfer quadrupole time-of-flight mass spectrometry (SICRIT-QTOF MS). Gas chromatography-mass spectrometry (GC-MS) analysis showed that the microcapsules retained 19 aromatic components, and their release kinetics conformed to first-order, Higuchi, and Weibull models. These results suggest that the electrostatic spray drying method combined with OSADS is an effective approach for preparing flavor microcapsules, ensuring efficient encapsulation and release of aromatic compounds.

Preparation of fern root resistant starch by pullulanase and glucoamylase combined with autoclaving-enzymatic method: physicochemical properties and structural characterization

BACKGROUND

Fern root starch has a high percentage of amylose and has great potential for application in the field of slow-digesting foods. Clarifying the effect of treatment conditions on fern root starch is key to achieving industrialized production of fern root resistant starch. In the present study, fern root starch was treated by the autoclave-enzymatic method with pullulanase, glucoamylase and mixed enzyme.

RESULTS

The content of resistant starch in fern roots treated with mixed enzyme was the highest (24.07 ± 1.11%), which was approximately 320% times that of the native starch, had the best water-holding capacity (151.08%), vital transparency and freeze-thaw stability. By contrast, the solubility, swelling and viscosity were lower than natural starch. In addition, mixed enzyme shows a denser structure, and the crystal form changes from C-type to V-type, with a high relative crystallinity and significantly enhanced thermal stability.

CONCLUSION

After mixed enzyme combined with autoclave treatment, the content of resistant starch in fern root was greatly increased. The modified starch molecules did not produce new functional groups, which made the crystal structure of starch molecules more compact, and resistance to enzymatic hydrolysis and high temperature thermal stability were significantly enhanced. This provides a positive reference for further in-depth study of fern root starch, improvement of utilization value, development and innovation of new food health products, and diabetes treatment. © 2024 Society of Chemical Industry.

Changes in Functional Properties and In Vitro Digestibility of Black Tartary Buckwheat Starch by Autoclaving Combination with Pullulanase Treatment

The processing properties of resistant starch (RS) and its digestion remain unclear, despite the widespread use of autoclaving combined with debranching in its preparation. In this study, the physicochemical, rheological and digestibility properties of autoclaving modified starch (ACB), autoclaving-pullulanase modified starch (ACPB) and native black Tartary buckwheat starch (NB) were compared and investigated. The molecular weight and polydispersity index of modified starch was in the range of 0.15 × 104~1.90 × 104 KDa and 1.88~2.82, respectively. In addition, the SEM results showed that both modifications influenced the morphological characteristics of the NB particles, and their particles tended to be larger in size. Autoclaving and its combination with pullulanase significantly increased the short-range ordered degree, resistant starch yield and water- and oil-absorption capacities, and decreased the syneresis properties with repeated freezing/thawing cycles. Moreover, rheological analysis showed that both ACB and ACPB exhibited shear-thinning behavior and lower gel elasticity as revealed by the power law model and steady-state scan. The degradation of starch chains weakened the interaction of starch molecular chains and thus changed the gel network structure. The in vitro digestion experiments demonstrated that ACB and ACPB exhibited greater resistance to enzymatic digestion compared to the control, NB. Notably, the addition of pullulanase inhibited the hydrolysis of the ACB samples, and ACPB showed greater resistance against enzymatic hydrolysis. This study reveals the effects of autoclaving combined with debranching on the processing properties and functional characteristics of black Tartary buckwheat starch.

Debranched Lentil Starch-Sodium Alginate-Based Encapsulated Particles of Lacticaseibacillus rhamnosus GG: Morphology, Structural Characterization, In Vitro Release Behavior, and Storage Stability

Starches with different degrees of debranching (DBS30, DBS60, and DBS90) and sodium alginate were used as the wall material for encapsulating particles of Lacticaseibacillus rhamnosus GG (LGG). The structural characteristics of these encapsulated particles were examined, along with the impact of varying levels of debranching on the encapsulation efficiency, the in vitro release of LGG under the simulated gastrointestinal environment, and the storage stability of the encapsulated particles. The results revealed a transformation in the crystalline polymorph from C- to B+V-type following debranching and retrogradation. This process also resulted in a significant decrease in molecular weight and polydispersity index, accompanied by an increase in amylose and resistant starch levels along with the relative crystallinity of the debranched lentil starch. Comparatively, DBS60-LGG and DBS90-LGG exhibited higher encapsulation efficiency and encapsulation yield than UDBS-LGG and DBS30-LGG. Furthermore, these encapsulated particles provided enhanced protection for LGG in both the simulated gastrointestinal environment and the storage process. It can be inferred that a superior encapsulation performance of the debranched lentil starch-sodium alginate-based encapsulated LGG particles was associated with higher debranching levels, a more uniform molecular weight distribution, and a more ordered multi-scale structure of the debranched lentil starch.

Preparation and characterization of porous corn starch-based antibacterial sustained-release intelligent film

A novel porous corn starch-based antibacterial sustained-release intelligent film was prepared with the porous corn starch as the substrate, purple corn cob anthocyanin (PCA) as the indicator, and tangerine peel essential oil as the antibacterial agent, and its properties were studied. The results showed that the porous corn starch-based antimicrobial sustained-release indicator film had good mechanical strength, surface hydrophobicity and light transmittance. The tensile strength of the sustained-release indicator film (PLSt-12) prepared by porous corn starch with an enzymatic hydrolysis time of 12 h was 14.35 MPa and the elongation at break was 6.55 %. The water contact angle was 89.10°, and the water vapor transmittance was 6.62 × 10-4 g·mm2·s-1·Pa-1. The PLSt-12 was brown at pH 10 and had a sensitive color response. The PLSt-12 reduced the release rate of anthocyanins by 25.01 %, and the sustained-release mechanism was non-Fick diffusion. It showed a significant color change when the pork quality deteriorated, which can be used to monitor the freshness of the pork. This type of antibacterial sustained-release intelligent film had considerable application potential in indicating food freshness.

Two-step modification of pullulanase and transglucosidase: A novel way to improve the gel strength and reduce the digestibility of rice starch

The multiscale structure, gel strength and digestibility of rice starch modified by the two-step modification of pullulanase (PUL) pretreatment and transglucosidase (TG) treatment for 6, 12, 18 and 24 h were investigated. The debranching hydrolysis of PUL produced some linear chains, which rearranged to form stable crystalline structures, reducing the digestible starch content, but weakening the gel strength. TG treatment connected some short chains to longer linear chains via α-1,6-glycosidic bonds, generating the structures of linear chain with fewer branches. The short branches promoted the interaction between starch molecules to form a more compact three-dimensional gel network structure, showing higher hardness and springiness. Moreover, these chains could form more stable crystals, reducing the digestible starch content, and the increase of branching degree inhibited digestive enzyme hydrolysis, reducing the digestion rate. The multiscale structure of starch tended to stabilize after TG treatment for 18 h, which could form a gel with stronger strength and lower digestibility than native starch gel. Therefore, the two-step modification of PUL and TG was an effective way to change the structure of rice starch to improve the gel strength and reduce the digestibility.

Effects of crosslinking with sodium trimetaphosphate on structural, physicochemical, rheological and in vitro digestibility properties of purple sweet potato starch

Purple sweet potato starch (PSPS) was modified using different amounts of sodium trimetaphosphate (0, 3-12%). Phosphorus content, crosslinking (CL), and substitution levels increased after modification. CL led to gradual agglomeration with each other through adhesion, compared to 0% STMP. X-ray diffraction did not change, but crystalline properties, swelling index, and peak viscosity increased, and solubility and glycaemic index decreased after crosslinking. Crosslinking increased, leading to a decrease of greater significance at 3% CL. Resistant starch was increased from 60.51 to 83.32%. G' and G'' values for crosslinking starch samples varied from 3086.00-5507.50 Pa and 513.92-800.30 Pa, respectively, after sweep test. The flow behavior index < 1 indicates that CL starch pastes are shear-thin. Positive and negative correlations were observed between gelatinized starch enthalpy and RS and between SDS and GI, respectively. The results lay the groundwork to comprehend the properties and relationships of CLPSPS and promote its possible use in foods.

Pullulanase: unleashing the power of enzyme with a promising future in the food industry

Pullulanases are the most important industrial group of enzymes in family 13 glycosyl hydrolases. They hydrolyze either α-1,6 and α-1,4 or both glycosidic bonds in pullulan as well as other carbohydrates to produce glucose, maltose, and maltotriose syrups, which have important uses in food and other related sectors. However, very less reports are available on pullulanase production from native strains because of low yield issues. In line with the increasing demands for pullulanase, it has become important to search for novel pullulanase-producing microorganisms with high yields. Moreover, high production costs and low yield are major limitations in the industrial production of pullulanase enzymes. The production cost of pullulanase by using the solid-state fermentation (SSF) process can be minimized by selecting agro-industrial waste. This review summarizes the types, sources, production strategies, and potential applications of pullulanase in different food and other related industries. Researchers should focus on fungal strains producing pullulanase for better yield and low production costs by using agro-waste. It will prove a better enzyme in different food processing industries and will surely reduce the cost of products.

Structural, physicochemical and digestive properties of rice starch modified by preheating and pullulanase treatments

The structural, physicochemical and digestive properties of rice starch modified by the combination of different temperature (60, 70, 80, 90 and 100 °C) preheating and pullulanase (PUL60, PUL70, PUL80, PUL90 and PUL100) treatments were investigated. The PUL60 treatment mainly modified the surface layer of starch granules, which increased the amylose content and damaged some ordered structures, resulting in slight decreases of gel strength and estimated glycemic index (eGI). With the increase of preheating temperature, PUL could act on more enzymatic sites to release a large amount of linear chains, reduce the ordered degree, and transform the A-type crystalline structure into B-type. The low molecule interaction strength between linear chains weakened the gel network structure, and some stable crystal structures formed by longer chains resisted the enzyme digestion. The gel strength and eGI value of PUL70 starch decreased significantly, and the properties of PUL80-100 starches tended to be stable, showing a further significant decrease of gel strength and a slight reduction of eGI value. Therefore, the preheating treatments at 60, 70 and 80 °C were suitable for the PUL modification of rice starch to obtain strong, medium and weak gel strength respectively, and the digestibility decreased with increasing preheating temperature.