Effects of the plasma activated water on the quality and preservation of fresh-cut lettuce

J. C. CHAMORRO; G. DENOYA; B. SANTAMARÍA; B. FINA; M. FERREYRA; E. CEJAS; A. RODRÍGUEZ; S. VAUDAGNA; L. PREVOSTO

Congreso; XX Materials Research Society (MRS) Meeting 2022; 2022

Plasma activated water (PAW) has rapidly emerged as a potential alternative to traditional sanitizers applied in the fresh produce industry [1]. In the present study, the effect of the application of 1 and 5 min treatments of PAW as washing agent on the quality and preservation of fresh–cut lettuce during 7 days of refrigerated storage was assessed. PAW was produced by using a liquid–cathode glow–type discharge in atmospheric pressure air and stored at 4 °C. PAW H2O2 and NO3– concentrations were 72.85 and 225.65 mg/L, respectively, while pH and electrical conductivity were 2.83 and 1533 μS/cm, respectively. No measurable amounts of NO2– were found. Twenty pieces of lettuce leaves were immersed for 1 and 5 min in 1 L of PAW. Lettuce chromatic parameters in CIE L*C*h° system and hardness with a texture analyzer were evaluated at 1, 3 and 7 days of storage at 4°C. Lightness (L*) significantly decreased with both PAW treatments, but significantly increased with storage time. The saturation (C*) of lettuce treated for 5 min with PAW was significantly lower than that corresponding to the 1 min-treatment. The angle of color (h°) was smoothly decreased from green to yellow with both the immersion and storage time of the lettuce. Lettuce hardness decreased significantly with storage time. Moreover, the microbial levels in the PAW–treated lettuce samples after the 5 min treatment were significantly lower than in the control samples, with a reduction of about 2 log. The last ones were promising results, since the quality of the product was almost not affected by the PAW treatments.