Tribology
Tribology is able to define more consumer preferences in apple textures than current technologies.
With thousands of varieties in the Vineland Research and Innovation Centre’s apple program, identifying the right fruits to move forward can take time; too much time and too much human involvement. Between 150 and 200 varieties are tested each year in Vineland’s Sensory & Consumer Services lab, but that’s a lot of bites for humans to take, chew and assess for texture.
Texture is somewhat of a holy grail in eating apples. According to Alexandra Grygorczyk, research scientist with Vineland, consumers want crisp and juicy apples. Mealiness is definitely undesirable.
“Apple texture is one of the major decision factors behind our breeding program,” she says. “Mealiness is a combination of things. Because it’s this complex attribute, it’s harder to identify. A lot of the elements that are creating mealiness are also common to friction.”
Up until 2021 a combination of a penetrometer and human sampling has been used to assess texture in apples, but through work with the University of Idaho, University of California Merced and University of Guelph, tribology – the principles of friction, lubrication and wear – is being used for the first time to determine hard food texture and specifically mealiness. Method testing in apples using tribology has been ongoing since 2018 and in 2021 with Lisa Duizer from University of Guelph and masters student Min Sung Kim.
“We’ll use this instrument to test [the apples] and then bring maybe 30 of them to people for testing,” she explains. “It’s a much more manageable number.”
A widely available attachment and relatively inexpensive modifications to a penetrometer makes all the difference, says Grygorczyk. The tribology equipment can measure crispness better than the penetrometer while also delivering results on mealiness and juiciness, which the penetrometer can’t reliably predict. This will essentially allow researchers to “kick out” apple varieties that don’t meet the levels of consumer preferences.
“For the most part, it works really well,” says Grygorczyk. “We’ve developed the method of how to screen apples… how that predicts juiciness, mealiness and crispness. It’s been done on foods like yogurts, custards, wines. This is the first time it’s been done on solid food.”
By using consumer preference mapping data, data points from apples that have been measured with tribology allow researchers to rank the fruit for commercial viability. One variety can be tested in about 10 minutes and Grygorczyk sees the ability for growers to send their apples in to Vineland for testing against consumer preference points.
Alexandra Grygorczyk
“We’re also looking at trying it in other crops as well,” she says. “But we’re hoping that other people in the apple world will pick up the method themselves. If you already have a texture analyzer, it’s just adapting existing equipment. Buy the attachment and make some small modifications.”
Human testing will still play a part in the leading 30 or so varieties determined by tribology, but as Grygorczyk explains, having a technological solution that reduces numbers of apples in the process will increase efficiency. It reduces the length of time as well as the volume of fruit required.
“You just cut the apple, take a piece off the end and stick [the apple] on the analyzer,” she summarizes.