Smallcaps are high risk , high reward products. One should think about this funds only if his risk appetite is very high.
Since it is a retirement fund avoid investing in risky funds such as midcap, smallcap. Avoid thematic also. U can have a look at hybrid funds . Park maximum funds in liquid instruments such as FD's or even short term debt funds.
In the current market , I feel its better to park it in debt funds and do STP's or switch in equity during market declines.
Look at the overall portfolio( % in midcap, smallcap and largecap) and choose accordingly as per your risk appetite.