I am obviously biased, but here goes. (I am retired now and don't benefit from anything I am going to say here.) I have been around the cherry orchards and the cherry industry my whole life. I was involved in the commercial launch of Montmorency tart cherry juice back in the day. I even picked cherries as a kid back in the 60s before the mechanical shakers came. It is a small industry, mostly in 3 counties here in northern Michigan, all small family farms. I think it's fair to say that juice sales saved those farms. The proximity to Lake Michigan and the rolling sandy eskers make for moderated temperatures and excellent water and air drainage - ideal conditions for fruit growing. Until about 30 years ago the farms were diversified - dairy, fruit and corn - the "three c's" - cows, corn, cherries. But the surviving farms now have specialized on fruit, especially cherries.
"Montmorency" is the name of the variety we grow here, an ancient variety thought to have been brought to the upper Great Lakes by early French settlers. It is the traditional American cherry pie cherry variety. Drums of concentrate were used in food processing, so that was available. When we first went online se started selling quarts of cherry juice. I can remember winter days in a cold unheated barn hand filling bottles.
We sent samples around to various researchers to test it for nutrition levels and were surprised to see the high levels of antioxidants beyond that of any other produce. The old timers here always said that cherry juice helped with aches and pains, but it was just anecdotal until the serious testing was done.
The rest here is my informed hunch about why the nutrition levels are so high. The first factor is the growing region, specifically the long photoperiods. The colors in plants - reds, yellows, oranges, blues - are caused by phytonutrients that act as antioxidants. The red color in fruit is from anthocyanins, which are powerful antioxidants. For the plant anthocyanins are UV protective. Fruit grown in the North has higher color as a result of the longer photoperiods during the summer. This is also why Autumn leaf colors are more intense in the North. As chlorophyll and the green color recedes, the other colors emerge. (It is interesting to speculate about why the colors that are attractive to us and other critters are also found in the most nutritious fruits.)
The second factor is that Montmorency is an ancient fruit. Modern fruit varieties have been selected for aesthetic factors and for durability in shipping and packing operations, and that can come at the expense of less flavor and lower nutritional values.
The third factor is that this variety is extremely perishable, so it is rushed from tree to processing very quickly, preventing degradation of the nutritional compounds.
When we first started bottling it, there would occasionally be a cracked bottle, a cap that didn't go on correctly, a label that was smeared, or for one reason or another a bottle would be rejected. Rather than throwing it out, the workers would drink it. So I got in the habit and have I've been drinking tart cherry juice every day for 30 years.
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