I've just started looking into similar questions for research into the
nutritional consequences of genetic engineering. Just yesterday I came
across some interesting sources that may be of use.
One is a book called Nutritional Qualities of Fresh Fruits and Vegetables,
edited by Philip L. White and Nancy Selvey (1974). There's a chapter
called "The Influence of Storage, Transportation and Marketing Conditions
on Composition and Nutritional Values of Fruits and Vegetables" which has
data on the loss of vitamins and minerals due to storage at different
temperatures. Other chapters look at the nutritional effects of home
storage and preparation, agronomic practices, varieties, harvest time,
technology of handling, and genetic engineering.
For time series data, the best I've found so far relate to specific crops.
I've been focusing on tomatos. For tomatos, there's great article from
1937 which analyzes the vitamin C content for 100 different varieties.
This should establish a baseline. Then there are more recent articles from
the 1960s and 1970s. And in the last few years the biotech companies have
been conducting nutritional analyses of their new crops for submission to
the FDA for approval (they need to prove, among other things, that nutrient
levels do not drop more than 20%, or outside of an acceptable range). I
can give you specific refs for these if you're interested.
Good luck, and let me know what you find, especially for the time series data.
-Evan Hansen
Energy and Resources Group
UC-Berkeley
>Hello - I have received similar questions lately regarding the nutrient
>content of foods relating to various growing conditions, post-harvest
>handling and changes in composition over the years.
>
>Specifically:
>
>1) Is there any data on the effects of exposure to cold on nutrient content
>of plants? (This has relevance for winter food production in protected cold
>frames.)
>
>2) What studies are there that address the effects of post-harvest handling
>practices on fresh fruit and vegetable quality and nutrient composition?
>
>3) Is there any time-series data that addresses nutrient composition from
>the 1940 compared to today?
>
>Any information would be helpful.
>
>Jennifer
>
>
>Jennifer L. Wilkins, Ph.D., R.D.
>Senior Extension Associate
>Nutrition Education, Food Systems and
> Community Food Security
>Division of Nutritional Sciences
>Cornell University
>Ithaca, NY 14853-4401