Pigment stability and material applications
Caldas-Cueva and colleagues studied an extract from dried ayrampo seeds purchased in Arequipa. Comparison with beetroot extract involved heating at 80°C at different pH values, storage at 4 and 25°C, and use in yoghurt. Colour stability depended on temperature, acidity and the type of system. In the yoghurt part of the study, samples were stored in the dark at 4°C for 35 days. These are the conditions of a technological experiment and do not establish a universal shelf life for every preparation. [Caldas-Cueva et al. 2016]
The long pigment half-life reported under refrigerated conditions comes from fitting a model to the observations. It does not mean that samples were observed throughout the calculated period. Pigment dose and fat content must also be considered when comparing products. The article was published electronically in 2015 and in a journal issue in 2016. The bibliography uses the issue year. [Caldas-Cueva et al. 2016]
Ayrampo pigments were also used outside food technology. Rivera Tito and colleagues incorporated an isolated compound into the emissive layer of a prototype organic light-emitting diode. Emission occurred in the powered device containing the extracted substance. The study concerns the properties of the organic material and does not describe the plant's own ability to emit light. [Rivera Tito et al. 2020]
Flint and colleagues used the extract as a dye sensitising a titanium dioxide electrode in a solar cell. A partially purified pigment with added citric acid achieved an efficiency of 1,41% under simulated AM1.5 light at an intensity of 100 mW/cm². The higher efficiency under illumination ten times weaker concerns a different measurement condition. The results demonstrate the prototype's ability to function and do not establish readiness to replace commercial cells. [Flint et al. 2024, Table 1, p. 9917]
Based on scientific publications. The scope of the experiments is stated alongside the results.
Stability of Betacyanin Pigments and Antioxidants in Ayrampo (Opuntia soehrensii Britton and Rose) Seed Extracts and as a Yogurt Natural Colorant
Caldas-Cueva J. P., Morales P., Ludeña F., Betalleluz-Pallardel I., Chirinos R., Noratto G., Campos D., Stability of Betacyanin Pigments and Antioxidants in Ayrampo (Opuntia soehrensii Britton and Rose) Seed Extracts and as a Yogurt Natural Colorant, Journal of Food Processing and Preservation, 2016, 40(3):541-549, doi: 10.1111/jfpp.12633
The experiments examine the stability of pigment extracts and the colouring of yoghurt. The authors compare the effects of pH, temperature, product matrix and storage time.
Extraction of 2′-O-apiosyl-6′-O-crotonic acid-betanin from the ayrampo seed (Opuntia soehrensii) cuticle and its use as an emitting layer in an organic light-emitting diode
Rivera Tito H. A., Hernández-Sosa G., Romero-Nieto C., Regulska E., Jürgensen N., Zimmermann J., Salazar-Salinas K., Quintana Caceda M. E., Extraction of 2′-O-apiosyl-6′-O-crotonic acid-betanin from the ayrampo seed (Opuntia soehrensii) cuticle and its use as an emitting layer in an organic light-emitting diode, RSC Advances, 2020, 10(60):36695-36703, doi: 10.1039/d0ra05543c
The paper describes the isolation of a pigment from seed coverings and its use in an OLED prototype. The results concern light emission by the device using this material.
Betanin dye extracted from ayrampo (Opuntia soehrensii) seeds to develop dye-sensitized solar cells
Flint H. V., Rivera Tito H. A., James R. D., Cucinotta F., Gibson E., Quintana Caceda M. E., Betanin dye extracted from ayrampo (Opuntia soehrensii) seeds to develop dye-sensitized solar cells, RSC Advances, 2024, 14(14):9913-9919, doi: 10.1039/d3ra08010b
The paper examines solar cells sensitised with ayrampo dye on a TiO₂ electrode. It presents the device's characteristics under different lighting conditions.