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Ljubic A.,University of Mostar | Juric A.,University of Mostar | Jakopovic K.L.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda
Mljekarstvo | Year: 2015

Treating food by ultrasound is a relatively novel food processing method which has been developed in the last two decades. When considering milk processing, ultrasound might be used to reduce the count of harmful microorganisms, and to stimulate the growth of probiotic bacteria during milk fermentation, especially bifidobacteria. The most commonly used probiotic cultures in fermented dairy products are bifidobacteria. The main problem related to the fermentation by bifidobacteria is that milk does not provide a natural environment for their growth and survival. Thus the application of bifidobacteria in milk fermentation is limited. Many studies indicated that the application of high intensity ultrasound (20 kHz) may shorten the duration of milk fermentation by B. infantis, B. brevi and B. animalis subsp. lactis. Also, studies showed that the stimulating mechanism of bifidobacteria growth by ultrasound was associated with the kinetics of carbohydrates and organic acids during fermentation. The aim of this review was to demonstrate how the application of the high intensity ultrasound stimulates the growth of bifidobacteria in the milk, and thus improves the fermentation process. © 2015, Hrvatska Mljekarska Udruga. All rights reserved.

Jelicic I.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda | Lisak K.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda | Bozanic R.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda
Mljekarstvo | Year: 2012

High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF) belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.

Jelicic I.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda | Bozanic R.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda | Tratnik L.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda | Lisak K.,Laboratorij za tehnologiju mlijeka i mlijecnih proizvoda
Mljekarstvo | Year: 2010

In the past two decades a lot of research in the field of food science has focused on new, non-thermal processing methods. This article describes the most intensively investigated new processing methods for implementation in the dairy industry, like microfiltration, high hydrostatic pressure, ultrasound and pulsed electric fields. For each method an overview is given for the principle of microbial inactivation, the obtained results regarding reduction of microorganisms as well as the positive and undesirable effects on milk composition and characteristics. Most promising methods for further implementation in the dairy industry appeared to be combination of moderate temperatures with high hydrostatic pressure, respectively, pulsed electric fields and microfiltration, since those treatments did not result in any undesirable changes in sensory properties of milk. Additionally, milk treatment with these methods resulted in a better milk fat homogenization, faster rennet coagulation, shorter duration of milk fermentations, etc. Very good results regarding microbial inactivation were obtained by treating milk with combination of moderate temperatures and high intensity ultrasound which is also called a process of thermosonification. However, thermosonification treatments often result in undesirable changes in milk sensory properties, which is most probably due to ultrasonic induced milk fat oxidation. This article also shortly describes the use of natural compounds with antimicrobial effects such as bacteriocins, lactoperoxidase system and lysozime. However their implementation is limited for reasons like high costs, interaction with other food ingredients, poor solubility, narrow activity spectrum, spontaneous loss of bacteriocinogenicity, etc. In addition, principles of antimicrobial effect of microwaves and ultraviolet irradiation are described. However their implementation in the dairy industry failed mostly due to technical and commercial reasons.

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