Many thanks for the responses @fareloz and @Abdullah , for your quick responses. However, I tried adding fragrance but the natural odour of shallots is overpowering and is spoiling the end product whose performance is very good though.
I am particularly looking for some compound that could first neutralize the odour before going on to add the perfume.
Alpha Aromatics manufacture 4-O-Dor details of which are copied below. I am unable to source it in India though.
4-O-DOR ™ For Skin Care And Fabric Products
N-Soya-N-Ethyl Morpholinium Ethosulfate
Recommended uses: Skin-safe odor reduction agent for use in cosmetics, skin care products, underarm deodorants, hair care products, air and fabric fresheners, pet coat and skin products.
Drop-in replacement for Forestall™*
Cationic with inherent softening and antistatic properties
Naturally derived from soybeans