Impact of pH and temperature on the colour and betalain content of Colombian yellow pitaya peel (Selenicereus megalanthus)

Abstract

The effects of different pHs (4, 5 and 6), temperatures (4, 20 and 80 °C) and storage (up to 12 days) on differential tristimulus colorimetry and betalain content related to the colour of yellow pitaya (Selenicereus megalanthus) have been investigated. The peel of the yellow pitaya was extracted with different solvents to see its colorant capacity. Highly-acidic extracts (pH 4) showed the lowest betalain content, chroma (C* ab = 60 against 70) and the yellow component of the colour (b*). Storage temperature manifested a great influence on CIELAB parameters when yellow pitaya peel was added to highly-acidic foodstuffs, with a tendency towards red hues (h ab , from 100° to 85°) and remarkable changes on lightness (L*, from 90 to 75) as temperature increased. However, low-acidic extracts (pH 5 and 6) were superior from a colour stability standpoint, not being influential the temperature of storage. All colour changes according to pH and temperature were visually appreciable by human eyes (∆E* ab > 3). New opportunities for diversification of colorant market could be possible by employing yellow pitaya peel as natural resource.

Betacyanin and Growth of Beetroot (Beta vulgaris L.) in Response to Nitrogen Fertilization in a Tropical Condition

“…It is clear that betacyanin content of beetroots determined at 536 nm was significantly higher (434.7 ml/l) than that at 538 nm (410.6 ml/l). An increase during storage at 20 0 C independent of pH was reported previously in the content of betaxanthins, a subclass of betalains besides betacyanins, extracted from yellow pitaya peel (Selenicereus megalanthus) (Cejudo-Bastante, Hurtado, Delgado, & Heredia, 2016). This suggests that beetroots stored at room temperature (± 20 0 C) for a short period (≤ 7 days) are better than that at low temperature (refrigerator or freezer) in term of betacyanin content.…”

Opuntia ficus‐indica (L.) Mill. fruit as source of betalains with antioxidant, cytoprotective, and anti‐angiogenic properties

“…Some studies have already investigated the chemical composition of different cultivars of cactus pear (Del Socorro Santos Díaz et al, ). The fruit colour depends on the pigments content, especially chlorophylls and betalains, which influence their stability (Cejudo‐Bastante, Hurtado, Delgado, & Heredia, ). In light of this, recently, betalains receive a lot of attention as food dyes.…”

Stenocereus griseus (Haw) pitaya as source of natural colourant: technological stability of colour and individual betalains

“…Considering that values of Δ > 3 evidence colorimetric differences perceptible to the human eyes (Martínez et al ., ; Fernández‐López et al ., ), a visually appreciable effect on Δ was produced between samples stored at 4 and 20 °C at each pH (Figure S2), confirming the thermolability of the Stenocereus griseus pitaya extracts (Cejudo‐Bastante et al ., 2014a, , ). The percentage of quadratic increases of lightness, chroma and hue (Δ 2 L *, Δ 2 C * ab and Δ 2 H * ab ) were also calculated in order to know the role of each colour attribute respect Δ 2 .…”