Phytochemical characterization, and antioxidant and antimicrobial activities of white cabbage extract on the quality and shelf life of raw beef during refrigerated storage

Abstract

Brassica vegetables are well-characterized, containing a wide-spectrum of phenolic compounds that are responsible for their diverse biological activities like antioxidant and antimicrobial activities. This study explored the preservative effect of Brassica oleracea var. capitate f. alba (white cabbage; WC) on beef under refrigerated conditions for 16 days. The antimicrobial activities of WC were evaluated against foodborne pathogenic bacteria and fungi. The antioxidant activity was determined on the basis of total phenolic and flavonoid contents, through employing DPPH and ABTS assays. The chemical composition was analyzed by GC-MS analysis. The results indicated that among the different solvent extracts, white cabbage chloroform extract [WCCE] exhibited outstanding bioactive properties due to the presence of 4-nitro-3-(trifluoromethyl)phenol, and the effects of WCCE at different levels (A and B) on the quality and shelf life of beef in storage were evaluated. The color parameters (lightness, yellowness, and redness), texture analysis, and pH values were monitored constantly with 4 days interval, and microbial analysis was conducted. The results showed that WCCE-A treatment significantly reduced the total viable counts, psychrotrophic bacteria, and yeast-molds when compared with WCCE-B and control during refrigeration storage, with the activity varying in a dose-dependent manner (p < 0.05). Significantly, the WCCE-A treatments had better appearance compared with the control after 16 days of storage. All results confirmed that WCCE which is rich in bioactive compounds, effectively maintains the quality of beef compared to the control by retarding lipid oxidation and microbial growth at refrigeration temperature and also emphasize the potential applications of this plant in different industrial sectors.

Fig. 1. Growth inhibitory activity of different extracts on growth of E. coli ATCC 35150 (a), and S. aureus ATCC 13150 (b).

Fig. 2. Antioxidant activity of different extracts of WC; CE: chloroform extract, TE: toluene extract, DE: dichloromethane extract, and ETE: ethyl ether extract.

Fig. 3. 2D and 3D structures showed the molecular interaction of LpxC with 4-nitro-3- of (trifluoromethyl)phenol.

Fig. 4. 2D and 3D structures showed the molecular interaction of 4PLB with 4-nitro-3-(trifluoromethyl)phenol.

Fig. 5. Chemotaxis assay of WCCE.

Fig. 6. Effect of white cabbage extract A and B on (a) total viable count, (b) yeast and molds and (c) psychrotrophic aerobic bacteria in beef meat during storage at 4 °C. Values representing mean ± SD of three replicates; different letters indicate significant difference (p < 0.05) for each time, same letters indicate no significant difference (p > 0.05) for each time.