Photo by Peter Toivonen
Cherry App
A new spectrometer could make judging cherry ripeness more accurate, help growers time their picking, help shippers select the best fruit for fresh or export markets, and ultimately improve post shipping quality.
Using colour as an indication of a cherry’s ripeness is a subjective process at best. AAFC researchers are developing data for using the SCiO, a spectrometer smaller than a cellphone, which can quickly and accurately measure dry matter in cherries.
“It is better to have a number, something that is objective rather than looking just at colour,” says Peter Toivonen, Research Scientist, Post Harvest Physiology, AAFC in Summerland. “I think we are going to find that dry matter which is an indicator of the sugar levels in a cherry, is a more reliable indicator of ripeness than colour."
Being able to accurately measure the ripeness of a cherry helps the industry in a number of ways. “I have one grower that I am working with who is hoping to map his orchard,” says Peter Toivonen. “He thinks that there is a non-uniform level of maturity across his blocks due to micro-climate effects and he wants to know which areas to begin picking so that he is always harvesting the fruit at the best time.”
Assessing ripeness after picking is a another use for the instrument, helping a packer choose between moving cherries quickly into the fresh market or knowing if they will be good for shipping overseas. “I think this is going be one of the keys for the BC industry,” says Toivonen. “You could sample, say, a selection of 100 cherries from a lot and if you find that 50% are over a certain limit, you might choose to not ship that fruit.”
Photo by Peter Toivonen
Cherry Spectrometer
Growers often leave cherries to ripen as long as possible before picking in order to have maximum flavour, but that may not work for fruit that will go into storage for shipping. “If someone complains that your cherries are bland and have no flavour after shipping, it is probably because you harvested them too late,” says Toivonen.
While very ripe cherries have a dry matter of up to 23.5%, Toivonen says fruit that ripe will lose both sugar and acidity more rapidly during shipping storage. “Our initial trials show us that a dry matter of no more than 20% is best for shipping ‘Sweetheart’ cherries.”
As BC cherry producers continue to build export markets for their fruit, post-shipping quality becomes an increasingly important consideration. “Post-harvest performance, that’s the gold standard; how do the cherries behave after storage,” says Toivonen.
In addition to taste, Toivonen’s research will consider firmness, acidity, the dry matter (sweetness) and if there are any defects that develop. “From there we will be able to draw some very nice models as to when you should start picking and what time you should get them picked by.”
