Use of high-intensity ultrasound as a pre-treatment for complex coacervation from whey protein isolate and iota-carrageenan

Abstract

The aim of this work was to evaluate the influence of high intensity ultrasound (HIUS) treatment on the molecular conformation of whey protein isolated (WPI) as a previous step for complex coacervation with iota carrageenan (IC) and its effect on the surface functional properties of complex coacervates (CC). Both biopolymers were hydrated (1% w/w) separately. A WPI suspension was treated with an ultrasonic bath (40 kHz, 600 W, 30 and 60 min, 100% amplitude). A non-sonicated protein was used as a control. Coacervation was achieved by mixing WPI and IC dispersions (10 min). FTIR-ATR analysis (400–4000 cm−1) detected changes after sonication on WPI secondary structure (1600–1700 cm−1), electrostatic interaction between WPI and IC by electronegative IC charged groups like sulfate (1200–1260 cm−1), anhydrous oxygen of the 3.6 anhydro-D-galactose (940–1066 cm−1) and the electropositive regions of WPI. Rheology results showed pseudoplastic behavior of both IC and WPI-IC with a significant change in viscosity level. Further, HIUS treatment had a positive effect on the emulsifying properties of the WPI-IC coacervates, increasing the time foaming (30 min) and emulsion stability (1 month) percentage. HIUS and complex coacervation proved to be an efficient tool to improve the surface functional properties of WPI.

Ascorbic acid encapsulation by complex coacervation of kappa carrageenan and calcium caseinate pretreated by high‐power ultrasound

“…Even though the lack of information regarding caseinate denaturation after US treatments, some information on US treated (20 kHz, 30% amplitude, 12.7 mm probe immersed 3 cm, time 0–15 min 5 s pulses) microfiltered casein micelle retentate showed the disaggregation and disruption of the dipole interaction among casein micelles, without a significant modification of the secondary structure (Yang et al, 2021). Besides, Vargas et al (2021, 2023) presented structural conformational changes in the secondary structure of whey protein isolate (WPI) subjected to US treatments with US probe (400 W, 24 kHz, 50% and 100%, 2 and 4 min) and US bath (600 W, 40 kHz, 100%, 30 and 60 min).…”

“…One of the trends that have presented interesting results is related to structural modification of the coacervate components before the coacervation process. From this perspective, Vargas et al (2021Vargas et al ( , 2023 evaluated the formation and characterization of whey protein isolated-carrageenan coacervates (kappa and iota), when the whey protein was pretreated by high-intensity ultrasound (HIUS). The results showed structural modification in the protein that resulted in increases in emulgent and foaming capacity in the coacervates compared to the coacervates without ultrasound (US) treatment.…”