Computers explain internal browning in storage

Internal browning of pears stored under low oxygen conditions is linked to restricted gas exchange inside the fruit, according to a study by researchers at the Catholic University of Leuven in Belgium.

The study suggests a computer model that can be used to improve long-term storage of fruit under controlled atmospheres.

Pears and other fleshy fruit are commercially stored under low oxygen conditions to extend their storage life for up to nine months. If the oxygen concentration in the storage atmosphere is too low, quality disorders such as internal browning can occur, causing major economic losses.

This disorder is known to be related to the complex mechanisms of gas exchange, respiration and fermentation in fruit. However, further conclusions are unavailable due to the lack of reliable methods to measure gas concentrations inside the fruit.

The team has developed a comprehensive computer model to predict the oxygen concentration inside the pear. The model incorporates equations for gas transport as well as for the respiratory metabolism. The researchers found that extremely low oxygen concentrations can occur in the core of the pear, which eventually may lead to cell death and browning.

While the model was developed for pears, it is generic enough to apply to other fleshy fruit and plant organs. But the tissue properties and the geometry of the different foods will need to be measured, said Bart Nicolaï, the team leader.