Anthocyanins in Wines and Juices Fall 2003 Brienne Olney

Timeline of inquiry (in terms of my question): What affect does temperature Have on seasonal color changes For different elevations? How are anthocyanin Concentrations affected By temp. in decid. Trees? Season ended too Quickly, no Leaves on trees How do growing conditions for the Different kinds of Grapes used in wine- Making affect antho- Cyanin concentration? Too expensive What are the different Concentrations of cyanidin-3- Glucoside in wines and juice and Does that reflect it’s color?

Where are anthocyanins found?

Background- Anthocyanins Water-soluble pigments Water-soluble pigments Responsible for pink to blue coloration in plants Responsible for pink to blue coloration in plants Not found in the plastids like other pigments but in the vacuoles Not found in the plastids like other pigments but in the vacuoles There are over 300 structurally different anthocyanins that have been identified in nature There are over 300 structurally different anthocyanins that have been identified in nature Have antioxidant properties Have antioxidant properties Are used as a food-colorant Are used as a food-colorant Anthocyanin concentrations are affected by processing Anthocyanin concentrations are affected by processing

More about anthocyanins… The most abundant form of anthocyanin found in nature is cyanidin-3-glucoside The most abundant form of anthocyanin found in nature is cyanidin-3-glucoside Has a molar absorptivity of 26,900 L/(mol·cm) Has a molar absorptivity of 26,900 L/(mol·cm) Has a molecular weight of 445 g/mol Has a molecular weight of 445 g/mol Has maximum absorption at wavelength of 510 nm Has maximum absorption at wavelength of 510 nm Red wines and grape juices are believed to have the highest concentration of anthocyanins and that they therefore have higher antioxidant properties (French paradox) Red wines and grape juices are believed to have the highest concentration of anthocyanins and that they therefore have higher antioxidant properties (French paradox) Cranberries also have a relatively high concentration of anthocyanins Cranberries also have a relatively high concentration of anthocyanins

Initial Model The darker liquids will have higher concentrations of cyanidin-3-glucoside; the darkest liquid will have the highest concentration while the lightest liquid will have the least. The darker liquids will have higher concentrations of cyanidin-3-glucoside; the darkest liquid will have the highest concentration while the lightest liquid will have the least. Concentration of cyanidin-3- glucoside Color density of liquid (wine/juice) Hypothesis: affects

Assumptions: Cyanidin-3-glucoside is the most abundant form of anthocyanin in each of the 8 samples Cyanidin-3-glucoside is the most abundant form of anthocyanin in each of the 8 samples Beer-Lambert law is an adequate equation to use to calculate the concentration of this form of anthocyanin Beer-Lambert law is an adequate equation to use to calculate the concentration of this form of anthocyanin There are no other components/pigments interfering with the absorbance at the wavelength of 510 nm There are no other components/pigments interfering with the absorbance at the wavelength of 510 nm

Methods Choose 8 samples of liquid to test, none of which have any artificial coloring added: Choose 8 samples of liquid to test, none of which have any artificial coloring added: Red wine (Cabernet sauvignon) Red wine (Cabernet sauvignon) White wine (Riesling) White wine (Riesling) Canned grape juice (Concord) Canned grape juice (Concord) Frozen grape juice (Concord) Frozen grape juice (Concord) Bottled apple juice Bottled apple juice Frozen apple juice Frozen apple juice Cranberry juice Cranberry juice White Cranberry juice (white cranberry and white grape mix) White Cranberry juice (white cranberry and white grape mix) Rank liquids according to density of color Rank liquids according to density of color

To the lab (measuring absorbance): Set the spectrophotometer’s wavelength to 510 nm Set the spectrophotometer’s wavelength to 510 nm Dilute the red wine, cranberry juice and grape juices so that the absorbance reading would be between 0 and 1 (for more accurate measurement) Dilute the red wine, cranberry juice and grape juices so that the absorbance reading would be between 0 and 1 (for more accurate measurement) Take readings for each sample Take readings for each sample Use the following equation to determine the concentration of each sample: Use the following equation to determine the concentration of each sample: C(mg/L)= A____× MW(g/mol) × DF × 10³mg C(mg/L)= A____× MW(g/mol) × DF × 10³mg Ε(L/mol·cm) L(cm) Ε(L/mol·cm) L(cm) A= absorbanceMW=molecular weight Ε= molar absorptivityL= pathlength

Data Tables and Graphs Table 1: Grape juices Red wine Cranberry juice Apple juices White wine White cranberry purpleRed amber goldenwhite Dark red Color Scale:

Red wine has the greatest concentration of cyanidin-3-glucoside. Frozen apple juice has the smallest concentration of C-3-G. White wine and white cranberry juice have no C-3-G. All samples:

Red wine (cabernet sauvignon) has much more cyanidin-3-glucoside than white wine (riesling). Just the wines:

Frozen grape juice has a greater concentration of cyanidin-3-glucoside than canned grape juice. Grape juices:

White cranberry juice does not have any cyanidin-3-glucoside while regular cranberry juice has 9.5 mg/L. Cranberry juices:

Bottled apple juice has a higher concentration of cyanidin-3-glucoside than frozen apple juice. Apple juices:

Evidence and Final Claim The color of the liquid doesn’t necessarily represent the amount of cyanidin-3-glucoside present The color of the liquid doesn’t necessarily represent the amount of cyanidin-3-glucoside present The grape juice had less anthocyanin than the red wine even though its color was darker The grape juice had less anthocyanin than the red wine even though its color was darker Neither the white wine nor the white cranberry juice had any cyanidin-3-glucoside Neither the white wine nor the white cranberry juice had any cyanidin-3-glucoside Even though the grape juices appeared to be the same color, their concentrations differed Even though the grape juices appeared to be the same color, their concentrations differed The apple juices also appeared to be the same color but their concentrations also differed slightly The apple juices also appeared to be the same color but their concentrations also differed slightly

Revised Theory/Model Concentration of cyanidin-3-glucoside Growing conditions: temp., UV exposure, etc. Methods used for processing ?? ? Antioxidant properties Color density Of liquid Not a direct relation Concen- Tration of Other antho- cyanins + ?

References Clifford, M.N. Anthocyanins-nature, occurrence and dietary burden. Journal of the Science of Food and Agriculture. 80: (2000) Clifford, M.N. Anthocyanins-nature, occurrence and dietary burden. Journal of the Science of Food and Agriculture. 80: (2000) Bancroft, W.D. The biochemistry of anthocyanins. Science. 98(2535): (1943) Bancroft, W.D. The biochemistry of anthocyanins. Science. 98(2535): (1943) Roberts, H.F. The causes of autumn coloration. The Scientific Monthly. 45(5): (1937) Roberts, H.F. The causes of autumn coloration. The Scientific Monthly. 45(5): (1937) Burns, J., Mullen, W., Landrault, N., Teissedre, P., Lean, M.E.J., Crozier, A. Variations in the profile and content of anthocyanins in wines made from cabernet sauvignon and hybrid grapes. Journal of Agricultural and Food Chemistry. 50: (2002) Burns, J., Mullen, W., Landrault, N., Teissedre, P., Lean, M.E.J., Crozier, A. Variations in the profile and content of anthocyanins in wines made from cabernet sauvignon and hybrid grapes. Journal of Agricultural and Food Chemistry. 50: (2002) And many more… And many more…

Happy Winter Break!!!