The isolation and properties of a concentrated red‐purple betacyanin food colourant from Opuntia stricta fruits

Abstract

A red-purple food colourant from Opuntia stricta fruits was obtained and studied. Four steps were involved in its isolation: washing, extraction, centrifugation and concentration. Ethanol:water 60:40 (v/v) was selected as the optimum extraction solvent to reduce the viscosity caused by the presence of mucilage and pectins. The resulting 40-fold concentrated extract had a high colour strength (3.9, OD 535 nm, 1% v/v sol), a high betanin concentration (4.7 g L −1 ) and low viscosity (59.0 cP). It also showed high stability (t 1/2 = 236.6 d, 4 • C) mainly due to its low pH (3.4) and low water content (571 g kg −1 ). These characteristics were in the same range as shown by three commercially available liquid concentrated colourants studied (red beet, red carrot and red grape skin). The colour parameters of this concentrated extract of Opuntia stricta were compared with those of commercial red colourants (red beet, red carrot, red grape skin, cochineal, elderberry, hibiscus and red cabbage). CIELAB values of Opuntia stricta (1.5 mL L −1 ) were L * = 69.8, a * = 59.7 and b * = −23.5. Opuntia stricta presented a vivid red-purple colour which was distinguishable from the colours shown by the other natural red food colourants.

Potential use of new Colombian sources of betalains. Colorimetric study of red prickly pear (Opuntia dillenii) extracts under different technological conditions

“…5), being the temperature an important factor on their pattern evolution. These results were in agreement with those obtained by Castellar et al (2006) in other species of Opuntia sp.…”

Armazenamento de figo-da-índia em pó

“…A palma (Opuntia ficus-indica Mill) possui frutos verdes e coloridos (vermelho, amarelo ou roxo), devido à presença de vários pigmentos da classe das betalaínas e betacarotenos (Castellar et al, 2006;Díaz et al, 2006;Tesoriere et al, 2005). Trata-se de uma cactácea que, apesar de ter sua utilização muitas vezes restrita à produção de cladódios para arraçoamento de animais, possui potencial para ser utilizada na produção do figo-daíndia, que se apresenta com teor de polpa semelhante ao da goiaba e em cuja composição se encontram princípios antioxidantes (Stintzing & Carle, 2004;Tesoriere et al, 2005).…”

Clarification of purple cactus pear juice using microfiltration membranes to obtain a solution of betalain pigments

“…The green ecotype is well known and has been cultivated for many years in many regions throughout the world. Some less well-known ecotypes yield other coloured fruits: purple, red, yellow and orange (CASTELLAR et al, 2006;DÍAZ et al, 2006;TESORIERE et al, 2005). The purple ecotype contains betalain pigments providing its characteristic colour.…”

“…Furthermore, cactus pear is one of the few natural sources of betalains, which are also found in beetroot, amaranth and some other Cactaceae such as the cactus pear, pitaya (Stenocereus sp. ), pitahaya (Hylocereus undatus) and garambullo (Myrtillocactus geometrizans) (CAI et al, 1998;CASTELLAR et al, 2006;DÍAZ et al, 2006;TESORIERE et al, 2005). Betalains are water-soluble pigments comprising two structural groups: betacyanins (red-purple) and betaxanthins (orange-yellow) (CASTELLAR et al, 2003;DELGADO-VARGAS et al, 2000;FORNI et al, 1992;SÁENZ, 2006).…”

“…Betanin (also termed "beetroot-red") is accepted amongst the natural pigments that are classified as additives E-162 (European Union) and 73.40 (FDA) (CASTELLAR et al, 2006). It is used mainly in foods that do not require thermal treatment, such as yogurt, confectionery, ice cream, syrups and sausages (FORNI et al, 1992;DÍAZ et al, 2006).…”