## 4 Food Applications
The antioxidant activity was also found to be retained and the negative sensory properties of peanut skin extract were eliminated when the encapsulated peanut skin extracts were used in flavored coatings for peanuts [109]. The bioavailability of phenolic compounds from peanut skins has been found to be low in the human intestinal tract, thus a study on producing edible films containing peanut skin extract which would allow for transfer through the oral mucosa was conducted [110]. Using a previously reported extraction scheme [44], peanut skin extract was incorporated into a gel consisting of gelatin and hydroxypropyl methyl cellulose and cast into films. Release of the polyphenols in the peanut skin extract after ingestion was found to be less than optimal due to binding with the proteins of the gelatin. Using the encapsulation procedure previously described [102], extracts of peanut skins were used to coat peanuts used in a clinical study of the hypergly response [111]. Human subjects who ingested a glucose solution along with the peanut skin extracts were found to have lower peak blood glucose levels at 45 minutes. This demonstrated the antidiabetic properties of the peanut skin extract prepared in this manner. The regulation of body fat and blood glucose by peanut skin extracts was evaluated in human subjects [112]. Aqueous extracts of peanut skins were dried and enclosed in gelatin capsules for consumption. Capsules were prepared to contain 200 mg of peanut skin extract powder. Sixteen adults ingested 2 capsules twice a day for 6 weeks. Other studies have shown peanut skin extracts inhibit \(\alpha\)-amylase [85, 87], so it was hypothesized that ingestion of peanut skin extracts would influence fasting blood glucose and body fat deposition. Although none of the subjects suffered from either type 1 or type 2 diabetes, some did have abnormal fasting blood glucose levels. These individuals were the only subjects that showed a significant decline in their body fat and fasting blood glucose. None of the subjects showed any negative effects on their kidney or liver function. This shows that peanut skin extract has the potential for use in blood glucose control. A more specific study used the isolated catechin, procyanidin A\({}_{1}\) dimer, and epicatechin-(4\(\beta\)\(\rightarrow\)6)-epictatechin-(2\(\beta\)\(\rightarrow\)O\(\rightarrow\)7, 4\(\beta\)\(\rightarrow\)8)-catechin (EEC) trimer that had been purified from hot water extracts of peanut skins [113]. It was found that the trimer had a dose-response effect on the digestive enzymes, \(\alpha\)-amylase and \(\alpha\)-glucosidase, but the catechin monomer and the dimer seemed ineffective. In addition, the trimer was able to suppress glucose transport in a cell system. As discussed above [29], extraction with acidified water followed by a partition into ethyl acetate was used to evaluate the thermal stability of the anthocyanins at pH values similar to those of various beverages such as carbonated drinks, teas, and energy drinks [114]. This was done to assess their value as functional food additives. Extracts from peanut skins using aqueous ethanol (17.7%) were used as an antioxidant in the coating for flavored peanuts and found to be as effective as BHT [115]. The effectiveness as an antioxidant in meat was evaluated using extracts prepared using only methanolas the extractant [116]. The addition of 400 ppm of phenolics from the extract extended the shelf life of the meat by 60% without affecting the color or cooking characteristics. There was no inhibition of microbial growth, however.