Utjecaj tretmana ultrazvuka snage 240W, 320W i 400W pri različitim temperaturama na kakvoću sirutke

master's thesis

• Title (english): Effects of ultrasound treatment power 240W, 320W and 400W at different temperatures on whey quality
• Author: Sonja Zubčić
• Mentor: Rajka Božanić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Milk and Milk Products); Zagreb
• Defense date and country: 2010-10-05, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svrha ovog rada je ispitati utjecaj djelovanja ultrazvuka visokog intenziteta na mikrobiološku kvalitetu i senzorska svojstva nativne slatke sirutke. Uzorci sirutke su tretirani ultrazvukom nominalne snage 240W, 320W i 400W kroz 5, 6,5 i 8 minuta samostalno, te u kombinaciji s temperaturom od 35ºC, 45ºC i 55ºC. Korišten je ultrazvuk visokog intenziteta konstantne frekvencije 24 kHz te sonde promjera 7 mm. Mikrobiološka kvaliteta sirutke određivana je mjerenjem ukupnog broja bakterija, broja koliformnih bakterija te kvasaca i plijesni. Svi dobiveni rezultati su uspoređivani s rezultatima nativne netretirane sirutke, te s uzorcima podvrgnutim visokoj kratkotrajnoj pasterizaciji (72ºC/15s) i niskoj dugotrajnoj pasterizaciji (65ºC/30 min). Rezultati su pokazali visoku djelotvornost ultrazvuka u kombinaciji s povišenom temperaturom na inaktivaciju mikroorganizama. Najznačajniji rezultati postignuti su ultrazvukom snage 400W pri 55ºC. Svi uzorci tretirani ultrazvukom bili su senzorski bolje ocjenjeni od netretirane i od pasterizirane sirutke. Najbolju senzorsku ocjenu postigla je sirutka tretirana ultrazvukom snage 320W pri 45ºC.

Abstract (english)

The purpose of this study is to test the effects of high intensity ultrasound on microbiological quality and sensory properties of nativ sweet whey. Whey samples were treated with nominal output power ultrasound of 240W, 320W and 400W through 5, 6,5 and 8 min alone, and combined with a temperature at 35ºC, 45ºC and 55ºC. In this work high intensity ultrasound with constant frequency of 24 kHz, with sonotrodes diameter of 7 mm was used. Microbiological quality of whey was observed through measurement of number of microorganisms, number of coliform bacteria and number of yeast and moulds. All obtained results were compared with results of native untreated whey, and samples treated with pasterization, high temperature, short time (72ºC/15s) and low temperature, long time (65ºC/30 min). Results have shown high efficiency of ultrasound combined with high temperature on the inactivation of microorganisms. The most significant results were obtained by ultrasound of 400W at 55ºC. All samples treated with ultrasound have shown better sensory rated from untreated and pasteurised whey. The best sensory rate scored the whey treated with ultrasound of 320W at 45ºC.

• Keywords: ultrazvuk; sirutka; termoprozvučivanje; kakvoća
• Keywords (english): ultrasonic; whey; thermosonication; quality
• Language: croatian
• URN:NBN: urn:nbn:hr:159:123396
• Study programme: Title: Food Technology; specializations in: Food Engineering; Course: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-08-29 08:12:56