lactic acids near the top of the paper. A significant limitation to paper chromatography is that it will not show exactly how much malic is still remaining in the wine, with the size of the "splotch" on the paper having no correlation to a quantitative figure. The sensitivity of the paper is also limited to a detection threshold of 100–200 mg/L while most measurements of "MLF stability" target a malic level of less than 0.03 g/L (30 mg/L). The enzymatic method allows for a quantitative measurement of both malic and lactic acids, but requires the expense of reagent kits and a spectrophotometer that can measure absorbance values at 334, 340, or 365 nm. Other products produced The main products of malolactic fermentation are lactic acid, diacetyl, acetic acid, acetoin, and various esters. The amount and exact nature of these products depends on the species/strain of LAB conducting the malolactic fermentation and the condition influencing that wine (pH, available nutrients, oxygen levels, etc.). Some strains of O. oeni can synthesize higher alcohols which can contribute to fruity notes in the aroma of the wine. Additionally, some strains of the bacterium have beta-glucosidase enzymes that can break down monoglucosides which are aroma compounds attached to a sugar molecule. When the sugar component is cleaved, the rest of the compound becomes volatilized, meaning it can potentially be detected in the aroma bouquet of the wine. In the early 21st century, some strains of O. oeni were shown to use acetaldehyde by breaking it down into ethanol or acetic acid. While this may help for wines with excessive levels of acetaldehyde, for red wines, it can also destabilize the color of the wine by interfering with acetaldehyde's reaction with anthocyanins to create polymeric pigments that help create a wine's color. Diacetyl Diacetyl (or 2,3-butanedione) is the compound associated with the "buttery" aromas of Chardonnays, but it can affect any wine that has gone through malolactic fermentation. At an odor detection threshold of 0.2 mg/L in white wines and 2.8 mg/L in red wines, it can be perceived as slightly buttery or "nutty" while at concentrations greater than 5 to 7 mg/L (5-7 ppm) can overwhelm other aroma notes in the wine.Martineau, B., Acree, T.E. and Henick-Kling, T "Effect of wine type on the detection threshold for diacetyl" Food Research International. Volume 28, Issue 2, 1995, Pages 139–143 Diacetyl can be produced by the LAB