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Acid-Base pH indicator using Black rice (Oryza Sativa L.) waste water

Description: Normally, pH meter is used to detect the pH but we can naturally produce our own acid-base pH indicator from anything that has anthocyanin such as red cabbage. However, the availability of a red cabbage in Sarawak is low thus we find an alternative of using black rice waste water

In Science form 2, there is a chapter regarding acid and base where students learn about various pH of solutions that they found at their homes such as vinegar or baking soda. Normally, pH paper or pH meter are used to detect the pH but we can produce naturally our own acid-base pH indicator from environments such as red cabbage. Anthocyanin is a natural purple pigment that responsible for purple-reddish colour in plants and fruits. Anthocyanin are ubiquitously found in fruits and plants such as blueberries, raspberry, mangosteen, blackberry and eggplant. Moreover, it is easy for us to identify plant containing anthocyanin which is by observing its purple colour. Here is the video for our invention https://youtu.be/bNF-jp7-9m4 In the western world, blended red cabbage water has been used to educate students regarding the ability of anthocyanin to change its colours depending on acidity or alkalinity of solutions. However, the availability of a red cabbage in Sarawak is low and rather expensive thus it is hard to expose students with this mesmerizing reddish-purple natural pigment. So, the objective of this project is to look for an alternative other than red cabbage in teaching students about anthocyanin. Therefore, my student was suggesting using Black rice waste water as an alternative because it displayed the similar colour with blended red cabbage. The methodology is simple; first, the Black rice needed to be soaked with water and stirred until dark purple reddish colour is formed. Then, filter the waste water to separate it from rice grains. Next, simply pour the black rice waste water into any desired solutions and observed, recorded the colour change. Our findings show that the black rice waste water does contain anthocyanin and behave similar with red cabbage because the solutions tested swiftly changes it colour when poured with the waste water. The colour of the solutions changed according to our expectations which in acidic condition it will turn reddish while in basic it will be displayed green to yellow. Thus, introducing black rice waste water as acid-base pH indicator to global community will definitely align with Goal 4: Quality Education of Sustainable Development Goals (SDGs). The implications are educators and students from across the globe will be familiar with Black rice that can exhibit similar characteristics with red cabbage and promoting the usage of black rice waste water as an alternative for natural acid-based pH indicator. Moreover, we hope to increase the popularity of Sarawak black rice across the world and indirectly improve the living of farmer in Sarawak.


Innovator(s): Muhammad Mizwar Mukhlis, Asmaul Afif Morny, Muhammad Azrin Fahmi Azri, Abang Mohamad Nadsreen Abang Adrus, Muhammad Najmi Fitri Norizam

Category: Chemical

Country: Malaysia

Gold Award