Extraction of Phenolic Antioxidant Compounds from Peanut Skins
Stephen Park and Ben Johnson
Biological Systems Engineering Department
Antioxidants are chemicals with an OH group that
neutralize free radicals, which damage the human
body, degrade tissues, and increase the rate of
aging. Antioxidants are currently extracted from
grape seeds or produced synthetically. Peanut
skins are currently a waste product with little or
no value, but they contain plenty of antioxidants.
Over 6,000 kg are produced per week in Virginia.
Current trends also point to consumers desiring
natural healthy products, two criterion this
satisfies.
Currently, the peanut skins are treated as a waste
which has no real value to processors. Phenolic
compounds such as dihydroquercetin, catechins,
and epicatehins are present in the peanut skins.
The phenolic compounds serve as sources for
antioxidants that protect lipids from oxidative
damage with proven uses in the biomedical and
food industries. Industry currently relies on
commercial antioxidants such as tert-butyl
hydroquinone (TBHQ), which are synthetic. While
laboratory-scale extraction methods exist, an
economical viable plant-scale process is needed
for extracting antioxidants from the peanut skins.
Economic Feasibility:
Design-Expert® Software
Total phenols
0.116977
Unit price of resveratrol on market: $8.33/g
Yield of 0.119 g antioxidants per g skins
Market value of antioxidants ≈ $8.00/g
Material cost (skins and solvent with recycle step) ≈ $0.08/g
Processing cost ≈ $0.30/g without labor
Break-even point: Ps = 3 Cg = 9 Cm
0.069431
X1 = A: Concentration
X2 = B: Temp
0.125
Actual Factor
C: Time = 17.13
0.114
Total phenols
Project Overview:
0.103
0.092
0.081
90.00
75.00
60.00
60.00
52.50
45.00
45.00
A: Concentration
37.50
B: Temp
30.00
30.00
Polyphenol assay for ethanol based on temperature,
concentration, and exposure time, to determine the ideal
setting with the three variables for optimal antioxidant
extraction conditions.
Based off of the break-even point formula and our research,
we would easily reach the break-even point and have a
potential profit of approximately 45.7 million dollars per year,
without including labor or start-up costs.
Mass and Energy:
Objectives:
Due to high solvent costs, anti-oxidants are
usually synthetically made while natural sources
such as peanut skins are left to waste. We
propose to design a large-scale process and a
plant design to extract natural antioxidants from
peanut skins with an economically feasible yield
and cost.
Conclusions:
A successful scale-up is possible and
recommended based on the results of this
project.
Process Flow Diagram (PFD) for the design to extract
antioxidants from peanut skin waste.
Acknowledgements: P. Mallikarjunan, T. Ballard, R. Grisso