Paper that morphs into soap when it touches water was among three winning ideas at an annual youth entrepreneurship competition. The wafer-thin "paper soap sheets" in environmentally friendly packaging were invented by team Oreo Crush with Pearls from Ngee Ann Polytechnic and Republic Polytechnic.

It was part of the third edition of the River Hongbao Hackathon held at the Mapletree Business City in Pasir Panjang on Thursday.

This year's competition challenged students to create environmentally sustainable or socially conscious business ideas on the theme of forging a brighter future.

The other winning teams are E-Duo from the National University of Singapore and Singapore University of Technology and Design, and Stick 'Em from Singapore Polytechnic and Eunoia Junior College.

Each team won $2,000 prize money and $5,000 seed money to develop and sell their product or service.

Sponsored by Mapletree Investments and supported by the Singapore Chinese Chamber of Commerce and Industry, the hackathon received a record 45 submissions. Participating teams comprised students, aged 18 to 29, from 11 local and private tertiary institutions.

The organisers are still finalising arrangements for the winning teams to sell their products or services.

In the last two competitions, the public could buy the young entrepreneurs' wares at the annual River Hongbao, the largest Chinese New Year event here.

On the efforts of the participants, River Hongbao 2021 organising committee chair Tan Aik Hock said: "It has been a challenging year for everyone, but in every cloud there is a silver lining. There are new opportunities to be explored and it is the next generation, our youth, who will carry us forward with their energy, passion and creativity."