Protein
Protein standard curve: Plot absorbance (l750nm) verses BSA (mg).
Fit the data point into a line of best fit by linear regression method
This is based on a theoretical expectation of absorbance directly proportional to amount (mass) of protein.
Determine mg protein for each replicate sample from its absorbance using the linear equation of your protein standard plot.
y = mx+C; where y=Abs, x=µg protein, m=gradient of line and C=y-intercept of line
This will give you mg protein/100 mL sample
Calculate total protein content of your mushroom extract (20 mL).
For each replicate, convert mg protein/100 mL to µg protein/ mL, then multiply by 20 for total protein (µg) in 20 mL of extract. Expressed the total protein as mg.
Express protein content as mass of mushroom (mg protein/g dried mushroom)
For each replicate, divide the total protein (mg) by the weight of the mushroom powder (g) to give mg protein/g dried mushroom. Express the replicate results as Mean±SD mg protein/g dried mushroom. Report the uncertainty (SD) to 2 significant figures.
Carbohydrate
Glucose standard curve: Plot absorbance verses mass (mg)
Xylose standard curve: Plot absorbance verses mass (mg)
For each standard curve, fit the data points into a line of best fit by linear regression method for each plot.
Determine mg glucose or µg xylose for each replicate sample from its absorbance using the linear equation of your glucose or xylose standard plot.
y = mx+C; where y=Abs, x=µg protein, m=gradient of line and C=y-intercept of line
This will give you mg glucose or mg xylose in samples.
Account for sample dilution in Step 4 (¼ dilution) and Step 9 (1/20 dilution) by multiplying by the total dilution factor of 80.
Calculate the glucose or xylose content as per gram dried mushroom by dividing by the mass of mushroom you used for the analysis (mg glucose or mg xylose/g Dried Mushroom).
Express your mean result as Mean±SD mg glucose/g or mg xylose/g dried mushroom. Report the uncertainty to 2 significant figures.
Antioxidant
Plot a Trolox standard curve of absorbance (l734nm) verses mass (mg Trolox).
Fit the data points into a line of best fit by linear regression method.
Deduct the color correction absorbance from the absorbance of your replicate samples
Using the linear equation of your Trolox standard plot, obtain the Trolox value (mg) for each replicate sample from their absorbance.
(y=mx+C; where y=Abs, x=mg Trolox, m=gradient of line and C=y-intercept of line.
Calculate TE of your food extract.
Divide mg Trolox for each replicate sample by 0.2 mL (sample assay volume) to give ug TE/mL extract.
Multiply by 20 mL (total extract volume) to give total mg TE.
Divide by 1000 to convert to mg TE.
Express the TE as dry weight of food (mg TE/g dry weight). This value is the TEAC of the mushroom.
You will need divide the mg TE by the dry weight of mushroom you used for your extraction.
For each replicate sample, calculate mg TE/g dry weight.
Express your result as mean±SD mg TE/g dry weight.
Calculate TE of your food extract.
