Scientists Have Invented a Machine That Sorts Pomegranate Seeds

Nearly 35,000 tons of pomegranates are produced in Spain each year, and the harvesting period is concentrated between the months of October and January. Until now a lot of the fruits were not commercialised.

24/11/08 A team of investigators from Valencia has developed a machine that separates automatically the seeds from the rind and pith of the pomegranate. The mechanism uses a computer vision system to distinguish and sort the different parts of this fruit, according to a study published on-line by the Journal of Food Engineering.

The difficulty in peeling pomegranates and separating out the seeds disheartens many consumers when they eat the fruit of the pomegranate (Punica granatum). Now a Spanish invention enables this food to be de-seeded automatically. “This involves a machine that discards the non edible parts and sorts the seeds according to their quality”, José Blasco explains to SINC and who is from the Institute of Agrarian Research in Valencia (Instituto Valenciano de Investigaciones Agrarias [IVIA]), where they have carried out research. The results of the research have been published recently in the Journal of Food Engineering, and the patent has already been requested.

The initial idea for creating this machine came from a project financed by the European Union for the comprehensive utilization of the pomegranate. A firm from Valencia became involved in the project and uses the machine to separate the seeds from the pomegranate and commercialises them.

The seeds arrive at the machine in a pile and mixed with the rest of the fruit, following a prior process of wholesale de-seeding. The material is placed on a conveyor platform with hoppers that organises it into a queue before going on to the “inspection chamber” where two videocameras record each object going through. Images are processed in a computer with vision software especially designed for this task that identifies what is seed from what is not (pith, rind, strange items from the countryside), in addition to evaluating the quality of the seeds.

This information enables the fruit to be put to one side in the “separation area”, which has four exits. When the system detects that an active skin is passing through, a “blast” is emitted from air projectors thus pushing it towards the first exit. By means of these “blasts” (which last about 30 milliseconds) the rest of the material is separated gradually. The seeds that do not fulfil the quality requirements demanded by the firm are eliminated through the second exit, prime quality seeds go through the third exit, and those of excellent quality go through the fourth exit.

Nearly 35,000 tons of pomegranates are produced in Spain each year, and the harvesting period is concentrated between the months of October and January. Until now a lot of the fruits were not commercialised because of their cracked and discoloured appearance due to “too much sun”, although in both cases the nutritive and organoleptic quality of the seeds was not affected. With the new machine these pomegranates will be used to full advantage.

The nutritional and anti-carcinogenic properties of the pomegranate fruits have been highlighted in various studies. Moreover this tree does not need fertilizers, phytosanitary products, or large quantities of water, and so adapts well to arid soils.