What was it all about?

A long-term goal of the macadamia industry has been to develop a test to predict the shelf life and quality of macadamia kernel. This project investigated electronic noses, which are widely used by major food and drink companies to measure and monitor product quality. They require minimal sample preparation and can objectively, safely and quickly characterise the global taste and odour profiles of ingredients or formulations.

The project used a prototype of an ‘electronic nose’ instrument, OdourScan, to measure the concentration of hexanal in the headspace of packaged macadamia nuts, which acts as a predictor of shelf life.

Simple, fast and economical protocols were developed, with each test taking less than 15 minutes, and providing a prediction in seven to 14 days.

Processing companies can now use rapid ageing and hexanal concentrations as part of their quality control program, and the outcome benefits other sectors of the industry through…

• Educating growers and handlers about the impact of poor handling practices on kernel quality and shelf life
• Monitoring and measuring quality decline through the supply chain
• Enabling quick and objective identification of product on supermarket shelves that is stale or rancid even though it may not be past the ‘best by’ date
• Assessing the potential shelf life of new cultivars being developed in the industry breeding project
• Assisting re-packers to set realistic and meaningful ‘best by’ dates
• Enabling rapid assessment of the effect of different packaging materials on storage stability.

The project resulted in a commercially viable, cost effective, rapid test for raw and roasted kernel.