Grape export industry gets a boost - new technology

The increasing role and contributions of commercializable innovation in the sciences can lead to the strengthening of the country's competitiveness in the international sphere and in growing the economy. These techno-entrepreneurs are the key to promoting and achieving these national objectives.

South African universities and technikons are home to hot new innovations in the sciences, health sciences and engineering fields. Highlighting these talents is the annual Catalyst Innovation Competition, targeted at recognising the commercializable innovations developed by students at all universities and technikons in South Africa in the Science, Health Science and Engineering Faculties.

One of the winners in this year's competition was Willie Opperman of Stellenbosch university for his innovation in the packaging of table grapes.

Export of table grapes gets new boost with latest technology: new polymeric SO2 gas-generating sheet - Dr Willie Opperman

South Africa is one of the major exporters of table grapes in the world market. For the 2000/2001 season it is estimated that SA exported in excess of 37 million cartons of grapes generating foreign capital to the amount of over R1 billion.

To reach these markets, fruit from South Africa spend an average of 4 weeks at sea and at least another week in cold storage at the market before it is sold. During this time grapes could be damaged by the bacteria Botrytis cinerea. The only means which is both practical and economical to ensure the quality of the fruit and prevent its decay by Botrytis cinerea during post harvest storage and during travel, is the use of special sheets for in-package SO2  gas treatment, combined with cold storage.

In South Africa however, rising costs of the locally manufactured and imported sheets, lack of availability and irregularly high SO2 emissions, coupled with stricter food legislation and changing export requirements of international buyers has stimulated thorough research to ensure that South Africa stays competitive in the world market.

New SO2  gas-generating sheet

In a research program initialised by South African table grape producers, an alternative polymeric SO2  gas-generating sheet (Vinguard™) was developed based on technology used widely in the pharmaceutical industry.

Vinguard™ consist of a polymer matrix with active release particles dispersed evenly through the matrix. Release of SO2 gas takes place through a monolithic release mechanism once the sheet comes into contact with the high levels of moisture present inside the grape packaging. Local and international patents protect the technology on which the Vinguard™ sheet is based.

During Willem Opperman's Ph.D. study a production process was developed and a small-scale production unit assembled to manufacture the Vinguard™ SO2  gas-generating sheets with a high degree of consistency and conformance to strict quality guidelines.

The performance of the Vinguard™ SO2  sheets compare favourably to commercial products. A major advantage of the Vinguard™ sheets is the degree of adaptability of these new sheets with regards to shape and size, and the ease by which the release profile can be manipulated (higher or lower SO2  emission levels), without the need for additional equipment or significant increases in cost.

The first phase to commercialisation will commence this coming season when limited quantities of these sheets will be made available to farmers. Manufacturing of the Vinguard™ sheets will be conducted on the small-scale production plant by Vinguard (Pty) Ltd., a company established and funded by the Deciduous Fruit Producers Trust (DFPT) to manage the transition of this project from a research project to a commercial venture.


November 2002