Fraudsters who mix cheaper long-grained rice with prized basmati to make profit, beware! Scientists have a way to expose such adulteration in future.
A team of researchers from India and the UK have developed not just one, but two devices that can detect adulteration in basmati sold in markets.
While one of the tests can be done using a hand-held device and thus faster, the other is a lab-based one, but 100 per cent accurate, the researchers led by Christopher Elliott, a professor at the Institute for Global Food Security at Queen’s University Belfast in Northern Ireland reported last week in a scientific journal,
“Basmati is a highly valued and premium rice and there are fraudsters who are making vast fortunes from selling fake basmati or adulterated basmati. We believe such basmati fraud to be substantial and on a global scale,” said Elliott.
Methods
The team, which included Ratnasekhar CH, a scientist from the Lucknow-based Central Institute of Medicinal and Aromatic Plants, a Council of Scientific and Industrial Research lab, developed two different techniques for exposing such food frauds. While one is based on near infrared (NIR) spectroscopy and can be deployed in a hand-held device, the other uses a lab-based instrument and works on principles of gas chromatography mass spectroscopy (GC-MS).
“Our NIR is very fast, very easy to undertake, and can actually be performed where rice is produced and traded. The accuracy of the method is around 90 per cent. Our GC-MS method is laboratory-based and will give close to a 100 per cent level of accuracy,” Elliott told BusinessLine.
Ratnasekhar explained it further. “The GC-MS method, which we have used in our work, does not require any rice sample preparation or solvent extraction, and no solvents are needed. Simply, it involves keeping the rice sample in a glass vial and straight away pass on the volatile compounds of rice to the GC-MS using solid-phase microextraction fibre,” said Ratnasekhar, who is currently in Elliott’s lab in Belfast.
The scientists, who used nearly 1,400 rice samples to test and validate the devices, said the ideal way to go about was to do a quick NIR test first and if this shows the rice to be suspect in terms of authenticity, a follow-up laboratory analysis is done using GC-MS.
In 2019-20, India exported 44.55 lakh tonnes of basmati worth over ₹31,000 crore. While there are a number of basmati varieties, the most prized ones are varieties known as Pusa 1121 and Taraori. As these two varieties are much in demand, cheaper varieties such as Pusa 1509, Sugandha, Sharbati and Shabnam are mixed with them and passed off as premium-quality basmati.
“Varietal mixing is done both deliberately and inadvertently. Around 5-10 per cent mixing of inferior-quality rice in premium basmati is allowed normally. Currently, the method used to detect is rather cumbersome DNA profiling technique,” said Ashutosh Sinha of Gurugram-based LT Foods, known for basmati brands such as Heritage and Daawat.
Grain of truth
According to the scientists, both types of testing methods are based on producing ‘food fingerprints’. The NIR generates a fingerprint of the rice in terms of how it absorbs light energy and produces a spectral pattern. Using multi-variant models, they can then differentiate high-quality basmati rice from adulterated rice.
The GC-MS test, on the other hand, produces a fingerprint of the volatile organic compounds that produce marker compounds to identify the special aroma of basmati rice and adulterants.