Rice Blend are not often used by WFP, for several reasons: 

• Rice is an expensive commodity (e.g. US$ 250/MT of rice vs. US$ 120/MT of corn)
• Rice is a cereal poor in protein (e.g. 7% protein in rice vs. 10% protein in corn)
• Rice is a cereal poor in fat (e.g. 0.5% fat in rice vs. 4.0% fat in corn)

But rice blend are easy to digest, neutral in taste, highly accepted by rice eaters.