Effective detection of proteins following electrophoresis using extracts of locally available food species

Procedures in life sciences research laboratories often require chemicals and plasticware that are costly, toxic or pose a risk to the environment. Therefore, sustainable alternatives would be of interest, provided that they generate suitable data quality. Coomassie blue and silver staining are the most widely used methods for detecting proteins following electrophoresis in the laboratory. However, their use presents challenges in terms of safety and waste management. In the current study, aqueous extracts were prepared from a series of common food species and evaluated as alternative stains for protein detection. Beets, blueberries, purple cabbage, raspberries and strawberries were employed to stain identical proteins separated under the same conditions in electrophoresis gels. Extracts of the first two species resulted in protein bands that were detectable through visible light transillumination, whereas extracts from all five species generated specific protein bands under ultraviolet light. The raspberry-derived extract was selected for further study based on the brightness of the fluorescent protein bands and minimal background staining. For both bovine serum albumin and lysozyme at 2.5 μg and 0.5 μg protein per band, the mean signal intensities obtained with raspberry extract staining were just below half of those obtained with Coomassie blue. Furthermore, the mean intensities using raspberry extract were equivalent to those obtained using Coomassie blue in the detection of 0.1 μg protein. Therefore, raspberry could be used to produce an effective stain for the routine laboratory analysis of proteins.