Effect of Different Wash Water Additives and Deep-Frozen Storage on the Quality of Curly Parsley (Petroselinum crispum var. crispum)

Curly parsley is widely applied as a culinary herb. Due to its growth close to ground level and its curly leaf structure, it is inherently affected by high counts of autochthonous microbiota, which may include pathogens. Washing of leaves prior to freezing is the only step in the processing of deep-frozen parsley enabling the reduction of viable counts. Therefore, the aim of the present study was to evaluate the efficiency of the washing water additives Nα-lauroyl-l-arginine ethyl ester (LAE) and lactic acid in comparison to chlorine as well as sole cold and warm water washing regarding their reduction of viable counts as well as their effect on the sensory quality of parsley. LAE reduced total viable counts, those of Pseudomonas spp. as well as Enterobacteriaceae by at least 2.0 log cfu/g, while lactic acid was especially effective against Enterobacteriaceae. Chlorophyll a and b and β-carotene were best retained during deep-frozen storage in products washed with LAE, while differences for nitrate contents and lipoxygenase activities between the different treatments were insignificant. Flavor ratings were highest for lactic acid treated parsley after 6 months of frozen storage. Thus, the investigated wash water additives were superior to chlorine in curly parsley processing.