P-27
Prediction of the sensory characteristics of bottled beer related to
instrumental measurements. Beer flavor will not be the same if stored at different conditions because of
the changes in its components. Beer quality is determined through sensory
evaluations by a trained panel but this quality assessment could be accomplished
by evaluation of physical chemistry components. Our objective was to predict the
sensory characteristics of bottled beer related to its composition, the
temperature and intervals of time of storing. Beer was elaborated with two
concentrations of oxygen (0.02 and 0.20 ppm) in a local industry, and 384
bottled samples of each one were taken and stored at 5, 28 and 60°C. Initially
and at intervals of seven days during sixteen weeks, the content of carbon
dioxide, pH, color, turbidity, TBA, and bitterness were instrumentally
evaluated. Simultaneously eight trained panelists evaluated grade of oxidation,
quality of bitterness and sensory stability. Data was divided into two blocks;
one was used to find the models of prediction and the other was used for
validation of these models. Since the data present multicolinearity, a multiple
linear regression by principal components was used to estimate the coefficients
of the model. These models explained 86-88% (p less than 0.01) of the changes of
the sensory characteristics. The general expression was Y equal B(o) plus
summation B(i)X(i) where Y is the sensory characteristic, B(o) and B(i) are
constants, and X(i) is the conjunct of oxygen concentration, carbon dioxide
concentration, pH, color, turbidity, TBA, temperature and time during the
storage. The models of prediction were validated by an algorithm written in
Matlab language These results suggest that sensory characteristics of bottled
beer would be predicted by instrumental measures of its composition and storage
conditions.
Nelson Bracho has a master degree in Statistics from the Universidad Simón
Bolivar. He has taught Quality Control at Universidad de Oriente for 15 years.
He is the advisor of investigations about quality and quality control in food
and food processes.
Otoniel Corzo and NELSON BRACHO. Department of Food Technology, Universidad de
Oriente Núcleo de Nueva Esparta, Boca del Río, Venezuela.