Low temperature extrusion promotes transglutaminase cross-linking of whey protein isolate and enhances its emulsifying properties and water holding capacity. (April 2022)

• Record Type: Journal Article
• Authors: Li, Jinpeng; Fu, Jinfeng; Ma, Yue; He, Yanting; Fu, Runxiao; Qayum, Abdul; Jiang, Zhanmei; Wang, Lizhe
• Is Part Of: Food hydrocolloids. Volume 125(2022)
• Publication Date: 2022-04
• Subjects: Extrusion pretreatment -- Whey protein isolate -- Transglutaminase -- Physicochemical properties -- Emulsifying properties; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2021.107410
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: Impact of extrusion pretreatment (50, 70, 90, 110 and 130 °C) on physicochemical, emulsifying properties and water holding capacity (WHC) of transglutaminase (TGase) cross-linked whey protein isolate (WPI) were investigated in this study. The results of molecular size distribution and SDS-PAGE proved that there were more macromolecular polymers formed in TGase cross-linked WPI after extrusion pretreatment ( E -WPI-TGase) and the consumption of free amino groups for E -WPI-TGase was the largest at the extrusion temperature of 50 °C and 70 °C. As the extrusion temperature increased from 90 °C to 130 °C, particle size of WPI after extrusion pretreatment ( E -WPI) was not changed significantly, compared with that of E -WPI-TGase (p > 0.05). In addition, the emulsifying properties, surface hydrophobicity and WHC of E -WPI-TGase were higher than those of WPI cross-linked by TGase (WPI-TGase) (p < 0.05). Significantly, the emulsifying activity, surface hydrophobicity and WHC of E -WPI-TGase at the extrusion temperature of 50 °C was increased by 63.78%, 18.58% and 96.63% compared with that of unextruded WPI-TGase, respectively. Therefore, these results indicated that low temperature (50 °C and 70 °C) extrusion pretreatment could promote the cross-linking degree of TGase-catalyzed WPI, and improve its emulsifying properties, WHC and surface hydrophobicity. Graphical abstract: Image 1 Highlights: ►Low temperature extrusion enhanced cross-linking degree of TGase-catalyzed WPI. ►Extrusion pretreatment improved emulsifying properties of TGase cross-linked WPI. ►Free amino groups of WPI were exposed by low temperature extrusion (50–70 °C). ►High temperature extrusion (90–130 °C) formed larger polymers through disulfide bonds.