The effect of packaging materials on the formation of 5-hydroxymethyl 2-furfural (HMF) was investigated. Red and white grape juice concentrates at 70 Brix filled into pouches from three different packaging materials including polyethylene/polyamide (PE/PA), polyethyleneterephthalate/polyethylene (PET/PE) and polyethyleneterephthalate/aluminum/polyethylene (PET/Al/PE) were stored at 28 and 37C for 6 months. HMF, browning index (A(420)) and clarity (% T-625) analyses were conducted by taking samples at 1th, 2nd, 3rd and 6th months during storage. The coefficient of determination, R-2 values for HMF formation, A(420) and % T-625 were 1.00. Statistical analysis showed that packaging materials, grape juice concentrate, storage temperature and time were significantly (P < 0.0001) correlated to HMF, A(420) and % T-625. Based on response surface and contour plots, optimum conditions for HMF formation, A(420) and % T-625 were: (PET/A1/PE) packaging materials, storage temperature of 36.53C and storage time of 1.22 months for white grape juice concentration and (PET/A1/PE) packaging materials, storage temperature of 28.12C and storage time of 5.80 months for red grape juice concentration.