The yeast’s resistance to sorbic acid in low sugar isn’t caused by changes in its internal acidity, because measurements showed the internal pH stayed the same regardless of sugar level or preservative exposure.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether intracellular pH consistently fails to mediate weak acid resistance in yeast across species, carbon sources, and preservatives.
A systematic review and meta-analysis of all published studies measuring intracellular pH in yeast under weak acid stress (sorbic, acetic, propionic) across glucose concentrations, including at least 25 studies with standardized pH measurement methods.
Whether artificially maintaining intracellular pH at high levels in low-glucose yeast abolishes sorbic acid resistance.
A double-blind RCT testing whether buffering intracellular pH to 7.0 (via ionophores or genetic manipulation) in S. cerevisiae under low-glucose (0.1%) and sorbic acid (200 mg/L) conditions eliminates increased resistance, compared to unbuffered controls, measuring growth and fermentation over 48 hours.
Whether yeast isolates from spoiled low-sugar beverages show no consistent intracellular pH profile compared to non-spoiled isolates.
A prospective cohort study measuring intracellular pH in 100 yeast isolates from spoiled and non-spoiled low-sugar beverages under sorbic acid stress, tracking pH over 72 hours and correlating with growth rate.
Whether yeast isolates from spoiled low-sugar beverages have different intracellular pH profiles than isolates from non-spoiled ones.
A case-control study comparing intracellular pH in 30 yeast isolates from spoiled low-sugar beverages (cases) versus 30 from non-spoiled counterparts (controls), under identical low-glucose and sorbic acid conditions.
The range of intracellular pH values observed in yeast strains isolated from commercial low-sugar beverages under sorbic acid stress.
A cross-sectional survey of 80 yeast isolates from retail low-sugar beverages, measuring intracellular pH under low-glucose (0.1%) and sorbic acid (200 mg/L) conditions using CFDA-SE staining and flow cytometry.