Global food waste is currently estimated to be 133 billion pounds annually and it is approximately one-third of global food production. Currently 83% of food waste ending up in landfills in the United States (US), and the food wastage's carbon footprint is estimated at 3.3 billion tons of CO2 equivalent, posing a huge environmental problem especially from methane liberated at landfills. Potatoes are the 4th most produced crop globally and are the most consumed vegetable in the US. Approximately two million tons per year of potato peels waste (PPW) are produced accounting for 3% of the total food waste stream in the US. PPW has about 55% carbohydrates, 20% extractives, 15% lignin and 10% ash (on a weight basis). The objective of our study is to determine the antioxidant activities of PPW to produce value added products. The dried and powdered peels of Russet Burbank potatoes were extracted by 50:50 methanol/water. The potato peel extractives (PPE) were evaluated by test of total phenolics contents (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, hydrophilic oxygen radical absorbance capacity (ORAC) assay, and HPLC analysis. TPC (29.998 ± 0.539 mg gallic acid equivalent (GAE) per g PPE) were higher than reported values. Chlorogenic acid, caffeic acid, p-coumaric acid and ferulic acid, were quantified in our extracts, with the former two being dominant. Our PPE showed high antioxidant capacity as measured using the ORAC and DPPH assays. Further studies were conducted to evaluate whether potato variety and extraction method affected the antioxidant activities. Two kinds of potatoes, russet potatoes (Solanum tuberosum 'Russet Burbank') and petite red potatoes (Solanum tuberosum 'Ruby Red') were extracted by two extraction methods (stirring and ultrasonic) and three solutions (methanol, water, and 50:50 methanol/water). The TPC were determined in these PPE. The data showed that extraction methods resulted in statistically significant different TPC (p&lt;0.05), with the ultrasonic method resulted in higher TPC. More study is ongoing with our collaborators to develop sustainable biorefinery capitalizing on abundant and underutilized food waste for manufacturing value added products in order to achieve a “circular economy”.

Antioxidant activities of potato peel extractives

2019 Fall National Meeting

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