Science Buddies: "Ask an Expert"

I am measuring the dry matter content of fruit by weighing slices of fresh fruit, drying them in an oven for 24hrs then weighing them again. This will give me a percentage dry matter content for each type of fruit so I can compare fruits. can you please give me some ideas as to how I can apply this informaton to human nutritional needs. for example marathon runners may need fruit with a high dry matter, dieters might prefer fruit with a low dry matter. I was wondering what diabetic people might need and what about other ilnesses?
Many thanks
Hannah

One additional thing which you'll want to consider for diabetics (this may be more important than simply the dry matter content but the two may be related) is how high on the glycemic index is a particular fruit? From http://www.kamut.com/english/allergy/nutrition-main.htm:

[QUOTE]
Foods low on the glycemic index means that glucose is liberated very slowly during digestion and supplies energy during a long period of time. Low glycemic foods are very important for diabetics, dieters and athletes who look for foods that do not stimulate insulin and fat-storage.
[END QUOTE]

Hi Hannah,

really a nice project theme.
I just know, That the dry matters of fruits play a important role in the processing industry. The industry would like to buy fruits with a high dry matter, so they have "more" fruit and less water, what is the opposite of dry matter and what they dont need.
An imortant fact for your experiment could be to find out of what the dry matters of the different fruits consists. For example a banana has a lot of starch, other fruits mainly out of sugars (interesting exeption:avocado mainly out of fruit fats and proteins), (just check the valuest out in the literature). As a result you could discuss the nutrition value better and you could also compare the fruits by its compounds.
Just an invented!!!! example:
Apples with dry matter of 20%. 35 % of the dry matter is sugar.
From 100g of fresh apple you get 20g dry weight. From this (35%) is 7g sugar. So if you eat 100g fresh apple you get 7g sugar.

Strawberries with dry matter of 10%. 70% of the dry matter is sugar. So 100g fresh strawberries have 10g dry weight. From this (70%) is 7g sugar.So if you eat 100g fresh strawberry you get 7g sugar (the same amount like apples which have double dry matter!!!).

Please notice that this is an invented example.
I just think!! that marathon runners would need quick energy so sugars, body builders need proteins, dieters would need no energy so high content of fibres, cellulose etc (which we can not digest). For diabetics its maybe important if the dry matter of the fruit consists mainly out of sugars, starch or fat. ???

Ok, wish you the best for your project.

Greetings from Germany,

Spaluny