Effect of ultrasaund treatment on physical and functional properties of whey proteins

Cilj ovog rada je uočiti utjecaj ultrazvuka na proteine sirutke kako bi se poboljšala njihova funkcionalna svojstva. Utjecaj ultrazvuka na fizikalno-kemijska i funkcionalna svojstva proučavao se preko mjerenja temperature, pH, svojstva pjenjenja i emulgiranja. Upotrijebljen je ultrazvuk niskog intenziteta (500 kHz) i visokog intenziteta (20 kHz sondom i 40 kHz u kupelji). 10 % modelne suspenzije izolata proteina sirutke i koncentrata proteina sirutke tretirani su ultrazvučnom sondom (20 kHz na 15 i 30 minuta) i ultrazvučnom kupelji (40 kHz i 500kHz na 15 i 30 minuta). Vrijednosti temperature povećale su se kod svih tretiranja modelnih suspenzija, a najviše kod tretiranja ultrazvučnom sondom visokog intenziteta (20 kHz). pH vrijednosti nisu se znatno promijenile. Koristeći sondu (20 kHz), ultrazvuk je utjecao na funkcionalna svojstva proteina sirutke, kao što su svojstvo pjenjenja i stvaranja emulzije. Koristeći ultrazvuk frekvencije 40 kHz imao je manji učinak na svojstva proteina, a bolji rezultati postignuti su tretmanom od 15 minuta nego tretmanom od 30 minuta. Tretman ultrazvučnom kupelji sa frekvencijom od 500 kHz nije imao utjecaja na svojstva emulgiranja i pjenjenja u modelu otopine proteina sirutke.The aim of this study was to observe the effect of ultrasound on whey proteins in order to improve their functional properties. Effect of ultrasound treatment on physicochemical and functional properties was examined by temperature, pH, foaming and emulsifying properties. In this work low-intensity ultrasound (500 kHz) and the (20 kHz probe and 40 kHz bath) were used. 10 % wt. protein model suspensions of whey protein isolate and whey protein concentrate were treated with ultrasound probe (20 kHz for 15 and 30 minutes) and ultrasound baths (40 kHz and 500 kHz for 15 and 30 minutes). Temperatures increased for all whey proteins samples upon ultrasound treatments, and the highest upon high-intensity ultrasound probe treatment (20 kHz). pH didn’t change significantly upon ultrasound treatments. Using 20 kHz probe, ultrasound affected functional properties of whey proteins like foaming and emulsion ability. Using ultrasound of 40 kHz frequency had less effect on protein properties and better results were obtained with 15 minute treatment than with 30 min treatment. Ultrasound treatment with 500 kHz bath didn’t had effect on emulsifying and foaming properties of whey protein model solutions