Application of fuzzy expert system approach on prediction of some quality characteristics of grape juice concentrate (Pekmez) after different heat treatments.

Effects of heat treatment on physicochemical characteristics and sensory properties of different fruit juice concentrates (pekmez) were studied. Apricot pekmez had the highest viscosity followed by mulberry and date pekmez. Apricot and date pekmez had higher scores for odour, taste and consistency than others. Hydroxymethyl furfural concentration of all pekmez samples increased after heat treatments. Samples heated at 75°C showed highest L* values while at 65°C the lowest mean L* values. L* values of all pekmez samples were similar while carob Pekmez had higher L* values. Also a development of the Fuzzy Expert System (FES) was made for prediction. Using the experimental values, FES model of the system was designed. Accordance was found with experimental and FES results when compared statistically. This study provides advantage for prediction possibility of unknown sub-values', which were not experimentally studied.