Articles
Gelling potential of native cactus pear mucilage
Article number
1343_61
Pages
489 – 496
Language
English
Abstract
The potential of native (un-purified) mucilage, extracted from the cladodes of Opuntia spp. to display gel-like behaviour, has been investigated.
Native mucilage (NM) could prove beneficial as a functional food ingredient by providing favourable economic/food-production advantageous.
Furthermore, mucilage in its native form is generally viewed as a by-product and is readily available.
Elemental analysis of the freeze-dried (FD) native mucilage (FD.NM) emphasises the high levels of calcium (Ca2+), magnesium (Mg2+) and potassium (K+) content associated with the mucilage extracted from Algerian and Morado cultivars.
Viscosity measurements at varying pH conditions was investigated at shear rates of 30 to 200 s‑1, at a constant temperature (25°C). The unaltered pH of all native mucilage solutions was found to be slightly acidic, with a pH 4.6-4.9 recorded.
All native mucilage (NM) and reconstituted (R) freeze-dried native mucilage (R-FD.NM) solutions displayed typical non-Newtonian, pseudoplastic flow behaviour.
Considering the flow behaviour index, (fitted to the Power law rheological model) NM and R-FD.NM solutions, for both Algerian and Morado cultivars, exhibited pseudoplastic or shearthinning behaviour, as all values reported corresponded to a flow index of n<1, regardless of the pH. The flow behaviour for R-FD.NM of both Algerian and Morado cultivars at increased pH 9-10 resulted in an increase in viscosity.
Interestingly, at a shear rate of 30 s‑1 under acidic pH conditions (pH 3-3.5), both NM and R-FD.NM showed increases in initial viscosity.
Considering the Bingham rheological model, the dynamic yield stress results showed that reconstituted mucilage under acidic conditions (pH 3-3.5) resulted in increased values, indicative of increased tendencies of the solutions to display weak-gel or gel-like properties.
It has been noted that varying levels of charged ions as well as pH can have consequential impact on application type and food quality.
Native mucilage (NM) could prove beneficial as a functional food ingredient by providing favourable economic/food-production advantageous.
Furthermore, mucilage in its native form is generally viewed as a by-product and is readily available.
Elemental analysis of the freeze-dried (FD) native mucilage (FD.NM) emphasises the high levels of calcium (Ca2+), magnesium (Mg2+) and potassium (K+) content associated with the mucilage extracted from Algerian and Morado cultivars.
Viscosity measurements at varying pH conditions was investigated at shear rates of 30 to 200 s‑1, at a constant temperature (25°C). The unaltered pH of all native mucilage solutions was found to be slightly acidic, with a pH 4.6-4.9 recorded.
All native mucilage (NM) and reconstituted (R) freeze-dried native mucilage (R-FD.NM) solutions displayed typical non-Newtonian, pseudoplastic flow behaviour.
Considering the flow behaviour index, (fitted to the Power law rheological model) NM and R-FD.NM solutions, for both Algerian and Morado cultivars, exhibited pseudoplastic or shearthinning behaviour, as all values reported corresponded to a flow index of n<1, regardless of the pH. The flow behaviour for R-FD.NM of both Algerian and Morado cultivars at increased pH 9-10 resulted in an increase in viscosity.
Interestingly, at a shear rate of 30 s‑1 under acidic pH conditions (pH 3-3.5), both NM and R-FD.NM showed increases in initial viscosity.
Considering the Bingham rheological model, the dynamic yield stress results showed that reconstituted mucilage under acidic conditions (pH 3-3.5) resulted in increased values, indicative of increased tendencies of the solutions to display weak-gel or gel-like properties.
It has been noted that varying levels of charged ions as well as pH can have consequential impact on application type and food quality.
Publication
Authors
B. van Rooyen, M. de Wit, G. Osthoff
Keywords
carbohydrate, functional, gels, ingredient, mucilage
Groups involved
Online Articles (75)