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The formation of amylose-lipid complexes, known as resistant starch type Ⅴ (RS 5 ), is limited by the low content of amylose in natural starch, increasing the amylose content is an effective approach to improve the yield of RS 5 . In this paper, an extrusion-debranching-complexing strategy with two extrusions was proposed to increase the formation of amylose-lipid complexes. A combination of corn starch (CS), pullulanase (60 U/g, w/w), and lauric acid (LA) with different contents of 4 %, 6 % and 8 % (w/w) generated enzymatically debranched extruded corn starch-lauric acid (EECS-LA) complexes after the second extrusion. The EECS-LA complexes were ordered form II complexes, with a significantly improved short-range molecular order. The melting temperature was in the range of 105-145℃. The enthalpy change increased with the increase of LA content and the value was 9.42 J/g for EECS-8 %LA complexes; these complexes could reform after dissociation. Scanning electron microscopy examination of the EECS-LA complexes revealed an irregular lamellar structure. The RS content of EECS-LA complexes increased significantly, achieving a value of 38.34 % for EECS-8 %LA complexes. This extrusion-debranching-complexing strategy is effective for preparing RS 5 and could be useful in industry for the continuous production of RS 5 ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Summary: 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 short branch chain and branching degree were generated as the degrees of hydrolysis (DH) increased. Intriguingly, no retrogradation occurred for the hydrolysates, even at DH 4.65%. Rheology reveal that the hydrolysate systems exhibited better fluidity and thixotropy. Furthermore, the resistant starch content of cooked WRS was elevated by 10.43% after MGA modification. The results indicate that MGA‐modified WRS was superior to other starches that have been reported in terms of inhibition of retrogradation and resistant starch content. Our data demonstrate the potential of enzyme‐based protocol for WRS modification using MGA alone to acquire clean and functional starch. [ABSTRACT FROM AUTHOR]

Starch and its derivatives play important roles in food industry. However, the application range of natural starch is limited due to its poor solubility and stability. Enzymatic treatment is one of the most commonly used methods to enhance the functions of starch and broaden its application spheres, which is characterized by strong specificity, high efficiency, and mild conditions. The applications of 4-α-glucanotransferase (4αGT) in the preparation of modified starch and its derivatives were reviewed in this paper, with emphasis on the mechanism of actions of 4αGT, changes of starch structure and properties after 4αGT treatment and the methods to improve the modification effect. Additionally, potential applications of 4αGT-modified starches and its derivatives in the food industry were also discussed and areas that need further researches were pointed out. 4αGT can catalyze disproportionation, coupling, hydrolysis, cyclization reactions. These reactions can be optimized by enhancing the expression level of 4αGT, combining 4αGT with other enzymes or physical and chemical methods, selecting suitable substrates; and optimizing reaction conditions. 4αGT treatments enhanced the properties and functions of starch mainly by changing amylose content, branch chain length distribution and molecular weight distribution. 4αGT modified starch and its derivatives have the potential to be used for encapsulating bioactive agents, creating reduced-calorie foods, sweetener, and prebiotics. Nevertheless, further studies are still needed to develop high-performance and safe 4αGT-modified starches and its derivatives. [Display omitted] • 4αGT catalyze disproportionation, cyclization, coupling, hydrolysis reactions. • The changes mainly focused on side chains, amylose content and molecular weigh. • The digestibility, freeze-thaw stability and gel property were mainly affected. • Further researches are needed to obtain desirable products. • Safety needs to be further explored in order to be widely used in food. [ABSTRACT FROM AUTHOR]

Modified potato starch with slower digestion may aid the development of new starch derivatives with improved nutritional values, and strategies to increase nutritional fractions such as resistant starch (RS) are desired. In this study, a correspondence between starch structure and enzymatic resistance was provided based on the efficient branching enzyme AqGBE, and modified starches with different amylose content (Control, 100%; PS1, 90%; PS2, 72%; PS3, 32%; PS4, 18%) were prepared. Through SEM observation, NMR and X-ray diffraction analyses, we identified that an increased proportion of α-1,6-linked branches in potato starch changes its state of granule into large pieces with crystallinity. Molecular weight and chain-length distribution analysis showed a decrease of molecular weight (from 1.1 × 106 to 1.1 × 105 g/mol) without an obvious change of chain-length distribution in PS1, while PS2-4 exhibited an increased proportion of DP 6-12 with a stable molecular weight distribution, indicating a distinct model of structural modification by AqGBE. The enhancement of peak viscosity was related to increased hydrophobic interactions and pieces state of PS1, while the contents of SDS and RS in PS1 increased by 37.7 and 49.4%, respectively. Our result provides an alternative way to increase the RS content of potato starch by branching modification. [ABSTRACT FROM AUTHOR]