The following foods are supposed to be single ingredient products. However due to processing issues and merchant dishonesty, purity might not be possible.
1) Fruit juice. The term sap and fruit juice are synonymous. Sap literally means a fruit extract. A pure form can only be taken by extracting your own fruit choice. During processing – water is added to add volume, preservatives to prolong storage life & artificial flavorings and nutrients to compensate for loss due to processing and dilution.
2) Honey. Very sweet and thick liquid gathered by bees from plant flowers. Some dishonest merchants are adding water and sugar syrup to increase income. A honey might be made with real sugar syrup. In areas where nectar sources are scarce, bees can be fed with syrup. The same is also fed during rainy weather when bees cannot fly to gather foods.
3) Sugar. Made by crystallization of sweet plant sap like sugarcane, beat, coconut and sugar palm. Might contain traces of sodium and other chemicals due to refining and bleaching.
4) Coffee. Popular coffee varieties are Arabica, Robusta, Excelsa and Liberica. Your favorite bean might be a single variety or a mixture of two or more. They are still pure coffee. However, it can be adulterated by a coffee like bean called chicori.
5) Vinegar. A product of acetic acid fermentation of alcohol or fruit wines. Not all vinegar from grocery shelves are natural. Some of them are just mixture of glacial acetic acid, water and cloudifier.
6) Roasted peanuts. How peanut is roasted? Place the carahay over medium flame stove. Drop the peanuts and stir it continuously to prevent scorching. Continue until crunchy. Based from my observation, roasted peanuts often refer to deep-fried peanuts with salt, garlic and chili.
7) Milk. Who will ever forget the popular melamine scandal. The powdered milk was mixed with melamine – a substance for making plastic wares. Fresh cow’s milk is pure but shelf stable brands are made by combining wide array of ingredients. Take a look at ingredient listing of popular milk powders.