The verification of intelligent properties of furcellaran films with plant extracts on the stored fresh Atlantic mackerel during storage at 2 °C

The newly developed intelligent pH-indicator furcellaran (FUR) films made with beet root (BTR), elderberry (EB), blueberry (BB), green tea (GT) and yerba mate (YM) extracts were studied to establish if they can serve as pH-change indicators and to establish how their color changes correlate with the changes of the microbiological (total aerobic bacteria, Pseudomonas, yeasts and moulds), physicochemical (TBARS, TVB-N, biogenic mines) and sensory parameters of fresh Atlantic mackerel during storage within a food packaging system at 2 degrees C. UV-Vis spectra and color of extracts changed at pH range from 1 to 14. The color changes were observed of red (FUR with BTR, BB and EB), orange (FUR with GT and YM), green in acid pH (FUR with BTR, BB and EB) and brown in alkaline pH (FUR with GT and YM). The fish spoilage test showed that the fish became spoiled between days 6 and 10 of storage as measured by the microbiological analysis. The TVB-N content of the fish samples did not significantly increase during the whole storage period reaching 17.14 mg/100 g after 14 days. The color changes of the films were not sufficient enough to effectively inform the trained sensory panelists of the spoilage of the stored Atlantic mackerel. The fish spoilage test showed that, despite promising preliminary results, the newly developed films were not suitable for use as intelligent pH indicators.