Thermoproteus uzoniensis 4-α-glucanotransferase catalyzed production of a thermo-reversible potato starch gel with superior rheological properties and freeze-thaw stability. (January 2023)

• Record Type: Journal Article
• Authors: Li, Xiaoxiao; Wang, Yu; Wu, Jing; Jin, Zhengyu; Dijkhuizen, Lubbert; Hachem, Maher Abou; Bai, Yuxiang
• Is Part Of: Food hydrocolloids. Volume 134(2023)
• Publication Date: 2023-01
• Subjects: Starch -- Thermo-reversible gel -- Gel stability -- 4-α-glucanotransferase; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2022.108026
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: 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 was evaluated by rheological assay. Only modified potato starch (MPS) exhibited thermo-reversibility, which prompted us to perform detailed analyses of the structural and gel properties of this product. The enzymatic modification resulted in a marked decrease in amylopectin side chains with a degree of polymerization (DP) < 23, while the contents of side chains with DP 23–43 increased. These data indicated that TuαGT preferentially extended the outer chains of amylopectin using amylose as a donor, which resulted in 17% increase in the amylopectin molecular weight to 3.0 × 10 7 g/mol. Notably, MPS displayed a delayed retrogradation and improved stability in four freeze-thaw cycles (−70 °C and 25 °C) as compared to the native starch. These analyses supported a model to explain the TuαGT catalyzed conversion of potato starch to a thermo-reversible product. Importantly, the MPS thermo-reversible 6% (w/v) gel showed comparable rheological properties to a 1.5% (w/v) κ-carrageenan hydrocolloid, highlighting the potential of MPS as a substitute to κ-carrageenan and other hydrocolloids of emerging health concerns. This work offers a starch based thermo-reversible gel and a methodological framework to broadens the use of starch into novel application as a food ingredient. Graphical abstract: Image 1 Highlights: Thermo-reversible gel was prepared from potato starch by modification with TuαGT. TuαGT had a preference for outer shorter chains in amylopectin. Thermo-reversible potato starch gel had excellent resistance to retrogradation. Thermo-reversible potato starch gel had good freeze-thaw stability. Modified potato starch gel of 6% had the potential to substitute for 1.5% κ-carrageenan.