Humans have been using milk from cattle for at least 10 000 years. During millennia, techniques for the refinery of milk to cheese have evolved resulting in the transition from small scale local production to the industrialized manufacture seen today. A problem faced today is the occurrence of dairy spoilage yeasts, of whom species belonging to the genus Candida is most prevalent. Methods to combat spoilage fungi involves the use of chemical preservatives, of which salts of sorbic acid are widely used. In water, the sorbate ion accepts a proton from the oxonium ion resulting in the formation of sorbic acid. Sorbic acid can diffuse into and over cellular membranes of yeasts, where it disrupts a range of functions. The most important being the disruption of proteins located in the mitochondrial membranes, resulting in an inhibition of the respiratory chain. The process of salting cheese is usually done by submersion in brine. The brine used is home to a diverse microflora, sometimes comprising said yeasts. The purpose of this work was to develop a method to investigate whether a reduced use of potassium sorbate in brine is possible. Two methods were developed, one where yeast was inoculated into different concentrations of potassium sorbate. The other used yeast in suspension derived from a simulated brining tank. The results showed that the simulated brining tank worked better, and a potential reduction to 1/3 of the current use of sorbate is possible. However, the experimental basis for this conclusion, even though supported by previous studies, is weak.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:lnu-130859 |
| Date | January 2024 |
| Creators | Thörngren, Elias |
| Publisher | Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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