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pH of chokecherry fruit #364089
Asked September 19, 2016, 8:11 PM EDT
Is there someone that can provide information concerning the fruit of Prunus Virginiana, more commonly known as chokecherry?
I am specifically interested in the pH range of the fruit.
I am a Master Food Preserver and we occasionally have inquires about chokecherry jam, jelly, and syrup and the need for added acid to render the product safe for pantry shelf storage.
Only a few scattered recipes exist and they fall either into added lemon juice or not and added pectin or not. I would like to sort out the various options and give safe advice.
In addition, would your refer me to any information sources regarding the acidity of White peaches/nectarines as opposed to yellow peaches/nectarines. I see occasional references to the need for added acid when canning the white varieties due to lower acid content,
Several references allude to White varieties being borderline fruits like figs, tomatoes, and Asian pears and the addition of added acid to the white varieties.is a safety issue.
Unfortunately, the persons responsible never are able to cite source material for that assertion.
I do not like fear mongering, and instead I want to rely on science and research based recipes.
There is a chart produced by the FDA with many common foods listed, but there is no breakout for yellow versus white.
Any help you can provide would be greatly appreciated.
Thank you for your time.
Darrell Fluman
Los Angeles County California
Expert Response
I found a reference for Chokecherries..
http://www.prairie-elements.ca/papers/nativequal.pdf
Chokecherry
Fruit of the chokecherry cultivars differed significantly in
their 10-fruit weights, percent pit, estimated percent flesh, pH,
and in the colour characteristics of their fruit juice (Table 1).
Ten-fruit weights of the cultivars ranged from 6.6 to 9.2 g.
Fruit of Goertz and Robert had significantly greater 10-fruit
weights than that of Mission Red and Boughen Yellow. The
percent pit was lowest for the fruit of Goertz (9.4%) and highest
for that of Boughen Yellow (16%). The estimated percent
flesh ranged from 17.2 to 23.7%, and was 24% lower for fruit
of Boughen Yellow than the average of the remaining cultivars
which did not differ significantly from each other. Total
solids content did not differ significantly among the cultivars.
Fruit pH among the cultivars ranged from 3.86 to 4.25. The
pH of the fruit of Garrington was significantly greater than
that of Boughen Yellow, Copper Schubert, Mission Red and
Robert. Large significant differences among the cultivars
existed in the hue angle of the juice extracts, ranging from
34.6 to 88.2°.
So it seems the pH can vary greatly, so the addition of acid would be beneficial in jell formation in the event there is not as much acidity as needed. Acidity will vary by season, maturity, location (this study was from Canada), and variety.
For peaches, while the yellow has slightly more acid, it tastes more acidic because of the brix/acid ratio. The pH is slightly lower, but not significant.
Reference - http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2621.1990.tb03922.x/epdf
It is always important to follow scientifically developed recipes such as those from the Center for Home Food Preservation. These recipes take into account varietal variations. In general, I would be more prone to adding acid than not.
