Extending the shelf life of sugarcane juice — naturally

Sugarcane juice is one of the world’s most popular beverages — but it’s highly perishable.

Now, food scientists from Australia and Pakistan have revealed a natural way to significantly extend its shelf life.

In their recent study, published in the journal Food Safety and Health, the researchers discuss how the addition of microwave-dried extracts of mint and coriander to the juice in the production process can extend shelf life from three days up to 14 days.

Sugarcane juice is widely consumed in South-East Asia, Africa and Brazil. More recently, it’s also become popular in North America and parts of Europe, driven by a growing consumer interest in natural, unprocessed beverages with perceived health benefits.

Its short shelf life is due to its high sugar and water content, with fermentation occurring rapidly once it is exposed to air. Normally, synthetic preservatives are added to slow this process, but they are falling out of favour due to their carcinogenic links.

Lead researcher Zarnab Asif, a University of South Australia PhD candidate who undertook this research as part of a Masters degree at the University of Agriculture Faisalabad (UAF), said that mint and coriander are safe, natural alternatives.

“Not only are they natural antioxidants; they also extend the shelf life of sugarcane juice for up to a fortnight. This has huge implications for the global juice industry, particularly in tropical regions where sugarcane juice is often produced and sold fresh on the street,” Asif said.

“We have shown that natural antioxidants from mint and coriander, extracted using microwave drying, can slow microbial growth and prevent the juice from turning dark or developing off-flavours. This is a simple, low-cost solution for the juice and beverage industry.”

The research team tested both traditional methods of methanol extraction and a new microwave-assisted drying extraction method. By heating the leaves, microwaves release extracts containing antioxidants such as polyphenols, flavonoids and vitamin C more efficiently, while avoiding damage to heat-sensitive compounds.

Co-author Dr Tayyaba Alvi from Green International University in Lahore said that the microwave-derived mint extracts displayed antioxidant activity of 74% — higher than both methanol extracts and fresh leaves. Coriander extracts also performed strongly, though slightly less effectively than mint.

“When added to sugarcane juice and refrigerated, the microwave extracts kept the juice fresh for two weeks, with minimal changes to colour or flavour,” Alvi said. “By contrast, juice treated with methanol extracts deteriorated within a few days.”

The research supports a growing consumer desire for natural products.

“People are becoming more cautious about synthetic additives, some of which are linked to health risks,” said principal investigator Dr Kashif Khan, from UAF.

“Herbal extracts provide a safer, plant-based option that not only preserves juice, but may also add nutritional benefits.”

Microwave-assisted drying also has the advantage of being more sustainable than methanol extraction, as it requires less time, solvent and energy than conventional methods, making it suitable for large-scale applications.

“Because this technology is simple and low-cost, it could be adopted by small and medium-sized juice producers in developing countries,” Khan said.

As a next step, the researchers intend to explore combining herbal extracts with other preservation methods, such as pasteurisation or innovative packaging, to further extend shelf life.

The study, ‘Shelf-Life Enhancement of Sugarcane Juice with Herbal Extracts: Extracted Through Novel Microwave-Assisted Technique,’ is authored by Zarnab Asif, Tayyaba Alvi, Muhammad Kashif Iqbal Khan and Arslan Kareem. It can be read at DOI: 10.1002/fsh3.70038.

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