LAHORE (Kashmir English): Pakistani scientists have developed a low-cost eco-friendly sensor that would detect spoiled milk.
Based on the natural compounds that give Jaman (Syzygium cumini) its vibrant purple colour, the sensor would help ascertain freshness of the commodity.
Pakistani researchers from the Department of Chemistry at the University of Education Lahore, in collaboration with the Interdisciplinary Research Centre for Biomaterials (IRCBM) at COMSATS University, Lahore have developed the low-cost java plum (Jaman) sensor that can detect spoiled milk.
Sensor from Jaman extracts and regular filter paper would help detect spoiled milk.
Fresh milk pH ranges from 6.5-6.9
Fresh milk has a pH ranging from 6.5-6.9, dropping to 4.4-4.5 when spoiled due to bacterial growth.
According to a report, the probe was without any electronics, rather the biologically driven.
The sensor, which changes colour, can effectively indicate whether milk is fresh or spoiled.
The team of Pakistani scientists isolated a natural compound called anthocyanin (ACN) from fully ripe Java Plum pulp. They then combined it with specific chemicals and passed it through filter paper to isolate it in its pure form, according to a research paper published in journal Food Chemistry.
To stabilise the compound, the fruit-infused liquid was dipped in a solution of chitosan — a sugar derived from the exoskeletons of crabs and shrimp — ensuring the ACN did not degrade or evaporate.
Anthocyanin is responsible for the rich colours in fruits, vegetables and flowers.
It is water-soluble and serves as a natural dye, also used in food colouring.
ACN is particularly sensitive to alkalis and acids, causing its colour to change when exposed to such environments.
Jaman’s unique property made it a prime contestant for extracting ACN to create a sensor that would change colour to flag spoiled milk.
Milk’s pH level is a key indicator of its quality. Fresh milk, whether from buffaloes or cows, typically has a pH level between 6.5 and 6.9.
As harmful bacteria increase, the milk becomes more acidic, with its pH dropping to between 4.4 and 4.5, rendering it unfit for human consumption.
The biodegradable and low-cost sensor has several advantages over traditional methods. “The purple paper sensor not only determines milk’s freshness and quality but is also more effective than many conventional sensors.
Using fruit pulp makes it an environmentally friendly invention that decomposes naturally, according to Dr Naeem Shabbir, a researcher at the University of Education Lahore.
