Physicochemical, nutritional, microbiological, and cytotoxic properties of freshly-squeezed raspberry fruit juice treated by cold atmospheric pressure plasma, operated in a flowing mode

Abstract

Consumption of different types of freshly squeezed fruit juices increased in the past few years. In this view, impeding the process of their spoilage is an economic and healthcare-associated challenge. Thus, here we applied cold atmospheric pressure plasma (CAPP) for elimination of microorganisms from a freshly squeezed raspberry juice (RJ), as we believe that the CAPP-mediated food preservation may be a tempting alternative for the juice-processing sector. Also the physicochemical, nutritional, microbiological and cytotoxic properties of the CAPP-treated RJ have been revealed. The CAPP-exposure of RJ led to 99.3 % reductions in the total viable count of natural microflora present in RJ. In terms of the artificially-inoculated sterile RJ, the proposed approach led to elimination of 100 % and 73.2–79.5 % of Escherichia coli and Saccharomyces cerevisiae cells, respectively. The so-treated RJ retained physicochemical and nutritional properties. In more detail, the pH of RJ was estimated as 2.74 ± 0.01 and 2.72 ± 0.03 for the untreated and the CAPP-treated RJ, respectively. Considering the color, it was found that the overall difference in tint was lower than 1.0, pointing out that the standard observer could not see deviation resulting from the CAPP-treatment of RJ. The volatile compounds profile, non-volatile compounds profile, and the determined concentrations of elements showed that in the studied RJ samples, mainly hexyl-hydroxyperoxidate, as well as Al, Ba, Ca, Cu, Fe, K, Mn, Na, Sr, and Zn were detected. Interestingly, the RJ subjected to CAPP exhibited cytotoxicity towards human colon adenocarcinoma (Caco-2) cell lines. The herein-proposed RJ processing method might be applicable for achievement of longer storage periods for freshly squeezed juices.