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While Jesus’ ability to turn water to wine would have been more appreciated by those being forced to go dry during lockdown, University of Stellenbosch researchers have used a bread fermentation process to turn bread into much-needed hand sanitiser.
Two postdoctoral researchers in the department of food science, doctors Stefan Hayward and Timo Tait, who have teamed up with MSc student Sebastian Orth, this week discovered that bread, which was composed of 40% starch, could be used as an excellent carbohydrate source to produce bio-ethanol via fermentation.
After their successful experiment, the scientists have realised that if you have the right equipment, some creativity and a few loaves of bread, you can do anything in times of crisis.
After a week-long process, the scientists were able to bottle the end product, hours before President Cyril Ramaphosa announced a countrywide lockdown last week, having made 18 litres of the alcohol-based hand sanitiser from stale bread crumbs in an in-house fermentation tank.
“It smells just a little bit like toast,” remarked Hayward.
Departmental staff were able to take a good supply of hand sanitiser home, with a few bottles left at the food science facility for authorised staff to further evaluate the experiment.
Hayward said: “Waste implies a need to discard something, which has become useless and needs to be disposed of. We see waste products and the tendency to produce too much food not as a problem, but as raw ingredients or by-products that can provide the impetus to invent new ways of reducing, reusing and recycling.
“During our brainstorming session, we were talking about alternative uses for some of the everyday items we often discard, bread being one of them.”
He added: “The global Covid-19 pandemic has highlighted the need for better hygiene practices and adequate supplies of antiseptic products such as hand sanitiser to help flatten the curve.
“Starch from bread can be used as an excellent carbohydrate source during the production of bio-ethanol via fermentation.”
They were able to obtain dried bread crumbs from one of their industry partners, Innovative Research Solutions (IRS).
IRS is currently helping a major food producer make something worthwhile out of the large amounts of bread returned daily to its distribution centres.
How does the fermentation process work?
In the department’s fermentation tank, the scientists combined 60 kilograms of bread crumbs with hot water and added alpha amylase enzymes, which are regularly used in the food industry, to the mix.
They then adjusted the pH level to optimal levels to convert starch to sugar. The pH level, which reflects the level of acidity – refers to the amount of hydrogen found in a substance like water.
The mixture was then incubated at 65°C for 60 minutes to enable saccharification and sugar production.
Thereafter, the mixture was cooled to 30°C before a specialised yeast strain used by the distilling industry, was added.
The end product, which looked very much like mashed potatoes, was left at room temperature for seven days until the fermentation process was complete and thereafter the mixture was distilled.
From the initial 60 kg of bread in their first batch, the academics were able to produce 10.5 litres of 75% ethanol.
Using a recipe found on the internet, it was combined with ingredients such as glycerol, hydro peroxide (that also kills viruses and bacterial spores) and a denaturant to ultimately make 18.2 litres of hand sanitiser.
brians@citizen.co.za
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