Quantification of betacyanin content variation of amaranth varieties by an Android App, colorimeter, and infrared spectroscopy

Betacyanin of amaranth leaves serves as an important food colorant. The study involves three methods (spec-trophotometer, Smartphone-based Color Grab App, and mid-Infrared Spectra) to measure foliar betacyanin con-tent variation in leaves, leaf extracts of seven amaranth genotypes, betanin standards. Absorbance values of sam-ples at 540 nm were measured using conventional spectrophotometry. It showed a significant linear regression with 15 leaf color attributes ( p = < 0.001 with R 2 = 0.77). The color grab app showed linearity (0.94), sensitivity (4.76 mu g mu L- 1), in betanin standards (0.025 to 7.5 mu g mu L- 1). It also had a limit of detection (0.18 mu g mu L- 1) and a limit of quantification (0.56 mu g mu L- 1). Absorbance was measured at 270 nm and 475 nm to understand protein and betaxanthin contents, respectively. Fourier transformed infrared spectra (399-4000 cm- 1) indicated correlation with betacyanin at 656 cm- 1, 665 cm - 1, 687 cm - 1, 689 cm- 1, 735 cm - 1, 737 cm- 1 and 741 cm- 1 wavenumbers. Android App-based non-invasive betacyanin estimation is significant to food processors, consumers, farmers, and a frugal science laboratory for educational & research institutions.

Automated summary

This study utilizes three methods (spectrophotometer, Smartphone-based Color Grab App, and mid-Infrared Spectra) to measure the variation of foliar betacyanin content in amaranth leaves. The results show significant correlations and provide non-invasive betacyanin estimation methods that are significant to food processors, consumers, farmers, and educational & research institutions.