Measuring friction might be the best way to determine apple quality, says a new project from the Vineland Research and Innovation Centre.
Tribology, the science of wear, friction, and lubrication, is commonly used in food processing for semi-solid products like yogurt and spreads. The institution says new research shows it’s also effective enough to replace existing methods of quality measurement in apples.
Why it matters: Vineland’s new approach to apple quality measurement could provide a new tool for processors and retailers.
The technology, however, appears more oriented to processors and retailers rather than farmers. A new, universally agreed-upon standard for some quality characteristics would also be necessary.
“Until now tribology hasn’t been used on hard foods,” says Alexandra Grygorczyk, a research scientist in Vineland’s department of sensory and consumer services, in a news release published by the institute.
“We found tribology was able to predict crispness, juiciness and mealiness — the most important texture features for consumers when eating an apple. Interestingly, we determined tribology is more effective than the industry standard penetrometer, for measuring apple firmness.
“Friction measurements using tribology equipment not only predicted apple crispness, which is related to firmness, but also mealiness and juiciness which the penetrometer is not able to predict reliably.”
Further investigations involved using a friction-measuring attachment on a texture analyzer, which is an instrument widely available within the horticulture industry.
“Findings showed with simple and fairly inexpensive modifications, a texture analyzer can be used to produce friction measurements strongly associated with texture perception by a trained sensory panel while outperforming a penetrometer,” said Grygorczyk in a release.
In a later interview, Grygorczyk said measurements would be taken via sample. Segments of a crop or shipment of apples are selected and placed in the friction-measuring device (a tribometer in Vineland’s case) that uses pressure to determine the sample’s characteristics.
Different areas of the value chain could make use of the technology, says Grygorczyk, such as farmers prior to harvest, breeders during the breeding process, or retailers keeping apples in storage. Overall, this would support domestic competitiveness.
Grygorczyk says the friction rig can be purchased for about $4,000 for a business that already owns a textural analyzer, but the overall cost is significantly higher for those who have to buy the analyzer. Friction analyzers are more commonly found among packers than growers.
Kirk Kemp, president of Algoma Orchards, a significant Ontario apple producer and processor, says his company employs “old-school” methods of quality measurement consisting of early-season starch tests and lots of pressure testing. Most electronic pressure-testing, he says, occurs within the processing plant rather than the orchards.
Measuring mealiness might be possible with new technology, says Kemp, but making use of the data would be difficult because no uniform mealiness standard exists. Every part of the supply chain would need to adopt a universal scoring system for it to work.
“That’s a bit of a hurdle. It’s like when we went metric,” he says. “What’s used today is the [sugar], acid, and pressure.”