Effects of surface coating treatments on the quality of washed fresh ginseng during marketing

To prevent the quality deterioration of washed fresh ginseng during distribution, the surface of fresh ginseng was coated with glycerol (Gly), soybean protein isolate (SPI), and sodium alginate (SA) at certain concentrations. The ginseng roots were put into a Polypropylene tray and sealed with a 0.035-mm thick oriented polypropylene film. After that, it was stored at 0°C for 10 weeks so as to determine changes in the quality. During storage, all the treated samples exhibited an increase in CO2 concentration and a decrease in O2 concentration in the package atmospheres. More specifically, the non-treated ones (CN), SPI-treated ones and Gly-treated ones had a 8-9% CO2 concentration while SA-treated ones encountered a lower concentration in the packages. The moisture content changed slightly with storage time, with relatively less changes in Gly-treated and SA-treated ginseng. There was no significant change in the firmness of the ginseng roots during their storage. During storage, ΔE-value changed the most in SPI-treated ginseng while it was almost the same in the remaining treatments, with the non-treated ginseng changing the least. The number of viable bacterial cells on the surface of the ginseng was 3.7-4.0 log CFU g-1 immediately after the coating and it increased as the storage period elapsed, with no distinct difference between the treatments. The number of mold counts was initially 3.2 log CFU g-1 and increased as the storage period elapsed, with the count for SA-treated ginsengs being 3.3 log CFU g-1 after 10 weeks, which was the lowest among the samples. In the sensory quality, the surface of SPI-treated fresh ginsengs rapidly discolored by 6 weeks and the quality of the rhizome and hairy root of CN- and SPI- treated samples largely deteriorated in 8 weeks, while the quality generally remained good in the Gly- and SA-treated ginseng.