Functional properties and sensory evaluation of mucilage from South-African cactus pear cladodes

A. Du Toit, M. De Wit, S. Naudé, M. Taljaard, H.J. Fouché, A. Hugo, S.L. Venter
The demand for functional foods is expanding as more consumers become obese or allergic to dairy, eggs and gluten. Functional food products could increase well-being, yet the undesired ingredients need to be replaced to restore the textural properties. Mucilage is a hydrocolloid gum, extracted from cactus pear cladodes that could transfer its function in plants to foods and be developed into a profitable functional ingredient. The investigation of the functional properties of extracted freeze-dried powders was necessary to predict the potential of South African cultivars as healthy ingredients. Freeze-dried powders of four cultivars (Opuntia ficus-indica ‘Algerian’, ‘Morado’, ‘Gymno-Carpo’ and Opuntia robusta ‘Robusta’) were dissolved in water or oil. After centrifugation (10 min at 5938.816 × g) and oven drying at 102°C for 24 h, the solubility-, swelling power, water and oil holding- and absorption capacity of the mucilage powders were determined. Emulsification capacity was determined by homogenizing freeze-dried powder with equal amounts of water and oil. The Leco Nitrogen analyzer was used to determine the crude protein content. Freeze-dried mucilage powders had a very high solubility index (78.8%), water (0.89 mL g‑1) and oil absorption (3.56 mL g‑1) as well as water (8.04 mL g‑1) and oil holding (1.22 g g‑1) capacities. It displayed high emulsification capacity (98.31%) and stability (87.79%). The protein content for the three O. ficus-indica cultivars was not significantly different (2.74-3.23 g 100 g‑1), but significantly higher in O. robusta (4.79 g 100 g‑1). None of the cultivars possessed significantly better functional properties. Native mucilage was applied in fat-, dairy and egg-replacement products. Mucilage showed promise as emulsifier and fat-replacer in mayonnaise products and was described as creamy with a highly acceptable mouthfeel. Mucilage is a natural, health improving product that the food industry could benefit from. It showed strong potential as a functional ingredient.
Du Toit, A., De Wit, M., Naudé, S., Taljaard, M., Fouché, H.J., Hugo, A. and Venter, S.L. (2019). Functional properties and sensory evaluation of mucilage from South-African cactus pear cladodes. Acta Hortic. 1247, 251-260
DOI: 10.17660/ActaHortic.2019.1247.34
Opuntia ficus-indica, Opuntia robusta, emulsifying capacity, water holding capacity, oil absorption capacity, solubility index, soluble fiber

Acta Horticulturae