Application of ultrasound on enzyme- modified cheese production and optimization of the production

Since heat treatments, which are widely used in the food industry for the inactivation of microorganisms and enzymes, can cause some negative changes, the tendency to alternative non-thermal technologies has increased. In this context, ultrasound technology stands out especially in terms of having different usage areas and suitability for industrial applications. There are various effects of the energy and forces occurred as a result of cavitation created by the ultrasound application on milk components may provide an increase in the yield and functionality of dairy products. It is reported that the activation energy decreases for proteins and enzymes as a result of the mechanisms created by low-frequency-high-energy applications of ultrasound at controlled conditions. Thus, with the effect of the cavitation mechanism that emerges depending on the application conditions (power, frequency, processing time), ultrasound technology has provided many advantages over heat treatments in the food industry and has started to find usage areas. In particular, the free radical level formed within the framework of the applied conditions is at a minimum level in low-frequency-high-energy applications. However, unlike enzyme inactivation, enzyme activation was achieved in some ultrasound applications, and in this respect, a separate and unique application area was opened from many other processes. In this direction, it was thought that this effect of ultrasound technology could play an active role in the production of enzyme modified cheeses (EMC). In this study, the production of EMC with similar quality characteristics in a shorter production time was tried with the application of ultrasound pretreatment. In the study, ultrasound power, ultrasound treatment time and proteolysis time were taken as process variables and productions were carried out in the range of 30-110 W for ultrasound power, 5-30 min for ultrasound treatment time and 2-12 for proteolysis time. The response surface method was used in the optimization of production process by taking into account the proteolytic ripening indexes (REI, RDI, and FAAI) and titration acidity as responses. The optimum conditions were determined as ultrasound power 46.28 W, ultrasound pretreatment time 9.8 minutes and proteolysis time 10.49 hours. At the same time, some additional production studies and the effect of process conditions were discussed within the scope of the thesis and the final product was characterized. As a result of the studies, it was determined that the US processing had a significant effects on the EMC properties, but the proteolysis time dominated. US power had no significant effects on EMC properties. It was determined that samples with properties close to the control EMC samples could be obtained in 1.5 hours of shorter time with the ultrasound pretreatment.and US treatment could accelerate enzymatic reactions.