DPIP is used to measure the rate of photosynthesis.
A decision has to be made about the amount of each product to use to get some sort of equivalent mass of yeast for comparison (and how this is arrived at; is there any indication of the % composition of the two products). Do the yeasts each have an optimum pH and if so what pH will be chosen for the grape juice (and why)? I know that the Lalvin BGY yeast from Burgundy, France is hopeless at pHs lower than 3.2 but other work at higher pHs. Is surface area a concern (maybe if one is a bottom fermenter, and another a top fermenting yeast). What temperature will be used (and why) if the yeasts have their own optimum temperature for growth; for example the BGY Lalvin yeast from Burgundy, France works best at 24°-28°C. Will a low sugar or high sugar juice be used - important as it may be the alcohol itself that inhibits the yeast. For example, the Lalvin CLOS yeast from Spain is high-alcohol-tolerant up to 15% alcohol but others give up before that. And what about the dependent variable (alcohol concentration): will the rate of alcohol production be measured, or just the amount of alcohol present when the yeasts die or the sugar runs out; or will the alcohol be measured after a set time, eg 7 days? Is time important? Some yeasts are slow (eg the CY3079 Slow White yeast from France takes its time but gets there in the end; it would be a brave decision to cut it off after 7 days). Lastly, some yeasts convert malic acid to alcohol (as well as converting the sugar). Imagine using a yeast such as the Lalvin C from France which partially degrades malic acid. Of course you'd get more alcohol out of this one.
Oxygen production is used to measure the rate of photosynthesis
be used to measure rates of photosynthesis ..
Before you do that, however, we advise you to have a quick look through the remainder of this section together with sections 2.2 and 2.3.
[In addition to the above coloured filters, we have made measurements of a number of neutral density filters and these are detailed in below].
The absorbance of a single thickness of each filter has been measured at 4 nm intervals using a Perkin-Elmer Lambda 9 Spectrometer and the data recorded.
Use a Spectrometer to measure color changes due to photosynthesis.
The iFL provides technology leadership. This is an integrated chlorophyll fluorometer – photosynthesis system with fully programmable microclimate control. It is the first integrated system to provide leaf absorptance measurement, an actinic light source that allows chloroplast migration as found in nature, automation of the instrument zero calibration and housekeeping functions to allow “walk away automation". Direct readout of gm, C, Γ* and R are included. It also includes F' correction option according to Loriaux 2013.