According to me, the best book for proximate analysis and data of Fruits and vegetables is of Rangana. Rangana. S. (1986) Handbook of analysis and quality control for fruit and Vegetable product. McGraw Hill publishing Co. Ltd, New Delhi
Why don´t you have a look at this book. A lot of food scientists in Germany work with it. http://www.amazon.com/Composition-Nutrition-Tables-revised-completed/dp/0849341418/ref=sr_1_2?ie=UTF8&qid=1377255403&sr=8-2&keywords=souci+fachmann+kraut
I found Rangana. Rangana. S. (1986) Handbook of analysis and quality control for fruit and Vegetable product. McGraw Hill publishing Co. Ltd, New Delhi very useful, easy to follow. Also in terms of accuracy of data obtained in their methods when compared to AOAC standard methods
In Italy the most authoritative website is the following: http://www.inran.it/ which contains the informations of the chemical composition of most feeds. Best wishes
There are three key databases which offer most common fruit and vegetable nutrition data. The aforementioned USDA , the Canadian Nutrient File ar both freely accessible and the the Euro Nutrient Database whic is not freely available links are here;
5. hand bllk of fruits and vegetables -http://priede.bf.lu.lv/grozs/AuguFiziologijas/Augu_resursu_biologija/gramatas/Handbook%20of%20Fruit%20and%20Vegetable%20Flavors.pdf