| Apple and orange juice packaged in bottles made of polyethylene terephthalate (PET), PET blended with 0.25, 1, and 4% polyethylene naphthalate (PEN), and PET blended with 0.25% PEN and 2% Amosorb were stored in dark, commercial fluorescent, and UV conditions for seven months. UV storage of apple juice in PET bottles resulted in ascorbic acid (AA) degradation rates over 3 times higher than in dark and commercial fluorescent storage. In UV, apple juice in PET bottles had an average AA degradation rate of 4.4 mg/L·day, while bottles blended with 0.25, 1, and 4% PEN gave rates of 2.67, 2.42, and 2.10 mg/L·day, respectively. AA degradation rates in orange juice were 1.15, 1.10, 1.00, and 0.98 mg/L·day for 0, 0.25, 1, and 4% PEN, respectively. Juices stored in dark and commercial fluorescent lighting darkened over time, while UV caused bleaching reactions. Colour loss was reduced for bottles containing PEN. |
