Modeliranje promjena fizikalno-kemijskih svojstava piva tijekom skladištenja u različitoj ambalaži

General properties of beer are subject to change while in storage, which makes the beer less attractive and even unmarketable. The aim of this research was to describe any significant changes in lager stored in different packaging [glass bottles, PET (polyethylene terephtalate), cans, kegs] by using mathematical models and statistical analysis. The data were collected during a period of six months and it shows significant changes in color (CL), foam (FO), dissolved oxygen (DO), haze (HZ), and easily evaporating components: acetaldehyde (ACE), dimethyl sulphide (DMS), diacetyl (DIA), and pentanedione (PEN). This paper presents a similarity comparison of significant changes using the correlation coefficient (r) in overall analysis of physicochemical properties and structure of beer in different packaging. The most significant changes are recorded in beer stored in PET. The properties of beer, which show the highest level of variability during storage are described using polynomial regression (PR) models with a coefficient of determination, \[R^{2}\] = 1. The model is validated (lager in PET packaging) while the correlation coefficient (r) confirms a similarity in changes for color (CL), r = 0.99, foam (FO), r = 0.94, haze (HZ), r = 0.98, and bitterness (BI), r = 0.59, between the measured values and the calculated polynomial values.