Whey protein is produced when manufacturing cheese - the curds separate from the whey as described in this article on whey protein.
Kiwi Nutrition offers two forms of whey protein:
Whey protein concentrate is the powder that is formed when water is removed from the liquid whey, and it contains about 80% protein, 5% carbohydrates and 5% fat, with the rest being moisture and trace elements.
Whey protein isolate is produced when the whey protein concentrate undergoes a another stage of filtration to remove as much of the fat and carbohydrates as possible. This results in a protein powder which has a higher protein content than whey protein concentrate. Kiwi Nutrition sources the premium version of whey protein isolate that is available in NZ. This has a protein content of 93%, whereas other less expensive forms of whey protein isolate have a protein content of 88.8%.
Whey protein concentrate or whey protein isolate, which is right for me?
Both WPC and WPI will help you reach and maintain your health, fitness and wellness goals. The level of fat and carbohydrates in our whey protein concentrate range is minimal, and this will be the right protein powder for most people.
However, WPI is often the preferred option for athletes who are looking to minimise their fat intake, or for those people with strict dietary requirements such as those on a high protein, low carb diet. Whey protein isolate is also useful for those who are sensitive to lactose - it is virtually lactose free so can be more agreeable to those with a sensitive gastrointestinal system. Whey protein isolate is also generally thought to be more rapidly absorbed so is often the preferred form of post-workout shake.