Real-time microsensor measurement of internal oxygen partial pressure in tomato fruit under hypoxic conditions

Internal oxygen partial pressure of tomato (Solanum lycopersicum L.) fruit was measured using a PC-Controlled, fiber-optic O-2 meter. Tomato fruit were subjected to hypoxic conditions via blockage of gas exchange at the stem end or by controlled atmosphere storage (4 kPa O-2 plus 5 kPa CO2). Internal O-2 partial pressure was evaluated in distal (i.e., blossom-end) tissue (10-mm depth). In both tests tomato fruit exposed to ambient atmosphere conditions had internal O-2 partial pressure of 18 kPa. Hypoxia was induced following lanolin application to the stem scar, and O-2 partial pressure decreased to 0.3 kPa after 1.5 h. During short-term CA application, the O-2 content of tomato was 1.0 and 0.2 kPa, alter 1 and 2h, respectively. This measurement apparatus shows promise for determining internal O-2 partial pressure ill soft fruits as affected by such external conditions as coatings, and modified or controlled atmosphere Storage. published by Elsevier B.V.