Final answer:
Manufacturers added melamine to wheat gluten to artificially inflate the measured protein content due to its high nitrogen levels, allowing them to misrepresent product quality and increase profits.
Step-by-step explanation:
Manufacturers in the melamine story were adding melamine to wheat gluten because it falsely inflated the protein content. Melamine is rich in nitrogen, and since the protein content of food substances like wheat gluten is often measured indirectly by measuring the nitrogen content, adding a nitrogen-rich substance like melamine can create the illusion of a higher protein level.
This deceitful practice allowed manufacturers to pass off inferior or diluted products as high-quality or to charge more without actually improving the product. The addition of melamine to food products is hazardous, as melamine's presence in food can lead to serious health problems in humans and animals.