Malate Utilization Monitoring MLF

The procedure of Kunkee (1968) is simple, relatively inexpensive to set up, and has an acid indicator present in the solvent. The indicator, brom-cresol green, undergoes a color change from yellow to blue in the pH range 3.8 to 5.4. Thus, the presence of an acid will be seen as a yellow spot on a blue background. 

Kunkee (1968) noted that old solvent may cause excessive trailing or smearing of the acid spots due to moisture accumulation. Because trailing 

The detection level for malic acid using this method is approximately lOOmg/L. Thus, the absence of a malic acid spot should not be taken to mean that MLF is fully complete (Section 11.3.4). Conversely, presence of a lactic acid spot may not confirm an ongoing MLF because these bacteria produce the acid from sugars (Section 2.4.1). To confirm MLF completion, it may be necessary to perform additional malic acid analyses using 

Adapted from Kunkee (1968) with the kind permission of Wines and Vines. 

Campos (1988) described an improved paper chromatographic method 

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