Antimicrobial And Antioxidant Properties Of Pickled And Dried Mustard And Its Application In Pork Preservation

As food safety becomes more and more serious, and it was found that plantpolyphenols can scavenge active free radicals in body, extraction of plant polyphenolsfrom natural products has been widely studied. In this study, antioxidant andantibacterial activities, and preservation efficacy of fresh pork of extracts frompickled and dried mustard were evaluated. The main phenolic acids in the extractswere also identified by HLPC. Our aims was to open up a new way forcomprehensive utilization of pickled and dried mustard.1. Antioxidant property of ethanolic extracts(EE) from the pickled and driedmustard were investigated. The extract obtained was successively fractionated usingliquid–liquid partition to yield petroleum ether, ethyl acetate and remaining fractions.The antioxidant activities of all the samples were evaluated with DPPH radicalscavenging and reducing power assays. Total phenolic contents were determinedusing the Folin-Ciocalteu method. Results revealed that all the samples showedantioxidant potential to varying degrees in the above two assays. Among thesesamples, ethyl acetate fraction(EAF) showed the best function in DPPH assay andreducing power assay. Furthermore, the EAF has the highest total phenolic contents(17.57mg GAE/g). The EC50of BHT, EE, petroleum ether fraction(PEF), EAF andthe rest fraction(RF) were0.07，2.20，3.06，0.65and3.92mg/ml respectively. Theorder of reducing power is BHT>EAF> PEF>EE>RF. In addition, the qualitativeanalysis of antioxidants that present in the extracts was carried out by HPLC. It wasfound that gallic acid was the major constituent in the ethanolic extract from pickledand dried mustard and its various fractions.2. The antimicrobial activities of EE, EAF, PEF, RF against Bacillus subtilis,Staphylococcus aureus, Aspergillus niger,Bacillus coli were studied by measuringinhibition zone diameter and the minimal inhibition concentration (MIC). The resultsshowed extracts of pickled and dried mustard inhibit the growth of three kind ofbacterium, but not Aspergillus niger. EAF showed stronger inhibitory effect.Antimicrobial property of EAF at the concentration of10mg/ml is close to sodiumbenzoate at the concentration of1mg/ml.3. The effect of the pickled and dried mustard in extending the shelf life of freshpork meat was investigated. Two processes were used. One uses EAF as preservatives. The other preserved pork meat by supercritical CO2simultaneous extraction andassisted-impregnance. Preservation efficacy was evaluated by measuring totalbacterial count, TBA value, TVB-N value, pH and sensory analysis. The resultsshowed that two processes significantly prolonged the shelf life of fresh pork. Basedon microbiological data, shelf life of pork meat was9days for samples treated withEAF,6days for samples by supercritical CO2treatment.