Development of cold plasma pretreatment for improving phenolics extractability from tomato pomace

In this study, high voltage atmospheric cold plasma (HVACP) with different working gases (air, Ar, He and N2) was used to modify the surface of tomato pomace, aiming to facilitate the migration of phenolic compounds during extraction hence increase their extraction efficiency. In addition to rupturing the epidermal cells of tomato pomace, HVACP treatments were found to decrease the water contact angle of tomato peels and accelerate the drying of tomato fruit, indicating that the treated surfaces were more hydrophilic. Tomato pomace treated by He and N2 plasmas showed increased extraction yields of phenolic compounds by nearly 10%, and all HVACP treatments increased the antioxidant capacity of tomato pomace extracts and slightly changed the concentration profile of their phenolic compounds. The developed HVACP pretreatment technology is a promising method for valorizing tomato processing byproducts with high nutritional values. Tomato pomace is a good source of phenolic compounds, however, the huge amount generated from commercial tomato processing has caused a severe waste problem. Conventional extraction methods for phenolic compounds are generally time-consuming with intensive use of organic solvents that are thus considered not environment-friendly. This new cold plasma pretreatment method can not only help mitigate the environmental burdens associated with agricultural waste management but also convert waste into value-added functional food ingredients and neutraceuticals in a more efficient way.