## 4 Food Applications  
In food, the use of peanut skin extracts as a functional food additive has been explored in several ways. Using water alone, peanut skins were extracted to create an infusion or \"tea\" [101]. Since the heat was required to produce the product, the chemical antioxidant strength was evaluated using TPC, Trolox equivalent antioxidant capacity assay (TEAC), and the ORAC assay. The result showed that the antioxidant potential was preserved and increased with the amount of peanut skins treated. The infusions were also found to be higher in response to the assays than green or black tea, indicating that peanut skins could have equivalent or better health properties. The preparation of an encapsulated product from peanut skin extracts produced a free-flowing powder that could be used for incorporation into foods was reported [102]. Antioxidant properties as defined by ORAC and total TPC were described. Using the extraction scheme of 70% ethanol in water followed by partitioning into ethyl acetate, a peanut skin extract powder was produced which was then incorporated at 0.02 and 0.1% by weight into raw meat that was then processed into a salami product [103]. After drying and storage, the products were evaluated by testing to determine lipid oxidation and sensory descriptors and compared to the synthetic antioxidant, butylated hydroxyanisole (BHA). Peroxide values were lower, but free fatty acid contents were not changed over untreated control. This showed the potential of peanut skin extracts as an antioxidant from a natural source. Use of peanut skin extract as an antioxidant in fresh meat described ethanol (80% in water) extracts incorporated into chicken meat ground and made into patties [104]. After cooking, the patties were stored under refrigeration. Using the thiobarbituric acid reactive substances assay (TBARS) as a measure of lipid oxidation, the addition of the peanut skin extract resulted in TBARS scores below 1.0 mg equivalents per kg. The control samples scored close to 20, proving the effectiveness when the peanut skin extract was added at 3.00%. A similar study used 80% ethanol in water as the extractant for peanut skins and the extract produced was tested for effectiveness as an antioxidant in patties produced using ground sheep meat [105]. Using the TBARS assay, the extract was compared to a synthetic antioxidant (BHT). The effect on the production of rancidity indicators was similar for the peanut skin extracts and BHT. Neither additive was effective against microbial growth. A brief review of the use of peanut skin extracts to preserve meat products is available [106]. This work focused on the effectiveness of peanut skin extracts, in particular the polyphenols to serve as antioxidants and antimicrobials. Recovery of the phenolic compounds on a scale to enable the use of the extract as a functional food ingredient has been studied. The skins from black peanuts were extracted with acidified water and then adsorbed onto a variety of resins to determine the most effective one [107]. Seven different commercial resins were compared and an apolar, macro-porous styrene-divinyl benzene resin produced in China with the trade name of DM-1, was chosen as the most effective based on adsorption and ease of desorption of the proanthocyanins with a recovery of over 18% of the dry weight of the original material. Using peanut skin extracts as an ingredient in food products causes problems due to the extreme bitterness and astringency properties of the material. These properties are attributed to the high tannin content. Using maltodextrin to encapsulate the extracts creates a free-flowing powder that is more easily handled and able to mitigate the negative flavor impacts [102]. Using the encapsulated material allowed for an increase in the chemical bioactivity as measured using the DPPH assay without changing the sensory properties when added to milk chocolate [108].