A novel approach to analyze total amino acids contents of food samples by computational image scanning densitometry

In the current work, computational image scanning densitometry technique was used instead of conventional and traditional instruments like IC, HPLC, GC and UV/visible spectroscopy for quantification of micro samples of amino acids (lysine hydrochloride, β-alanine, asparagine monohydrate, glutamic acid). The general reaction between locating reagent and amino acid is: This technique has accuracy at the parts per billion level and precision as indicated from percent recovery from sample analysis, which is quite good. Due to certain limits associated with conventional techniques, this technique may be presented as a progressive and important event in the history of evaluation at micro level. Keywords: amino acids, densitometry, micro level.

Analysis of polyphenols, phytosterols, and bitter principles in Teucrium L. species

Total polyphenols, tannins, β-sitosterol, and bitterness values were determined in native and cultivated populations of Teucrium L. species from Croatia (T. arduini L., T. botrys L., T. chamaedrys L., T. flavum L., T. montanum L., T. polium L., and T. scordium L. subsp. scordioides Schreb.). Teucrium species have long been present in folk medicine for diverse medicinal uses, but little is known about polyphenols, phytosterols, and bitter principles. Spectrophotometrically determined contents of total polyphenols (TP) and tannins (T) significantly varied among investigated Teucrium species and were somewhat higher in native populations. The highest TP and T contents were measured in native specimens of T. montanum (TP: 13.68%; T: 3.48%). Scanning densitometry was used for measurements of β-sitosterol levels in plant samples ranged from 0.056% (T. montanum) to 0.129% (T. botrys), and it was not significantly different between native and cultivated specimens of the same plant species. Bitterness values were similar for native and cultivated samples of the same plant species; the highest was measured for T. montanum (15659). The present study suggests that Teucrium species growing in Croatia have potential for cultivation and might be a valuable source of natural bioactive compounds.