Nutritional Characterization and Determination of Processing Suitability of Edible Wild Cactus (Opuntia spp) Varieties found in Kenya

Abstract

Edible wild cacti (Opuntia spp.) are considered to have a promising commercial application in the food industry due to their nutritive composition and drought resistant nature. However, knowledge on their nutritive composition and processing suitability in Kenya is still limited. This study sought to identify the main edible wild cactus varieties in Kenya and determine their nutritional characteristics in order to unlock their industrial potential. Cactus plant descriptors based on FAO-ICARDA Cactus Net guidelines were used to identify the edible cactus fruit varieties from four Kenyan Arid and Semi-Arid lands (ASALs) counties (Machakos, Baringo, Makueni and Laikipia). The estimated yields, morphological, physicochemical, and sensory quality parameters of the fruits were determined and fruit-based products were processed. Three edible cactus fruit varieties were identified namely: Opuntia stricta (purple), Opuntia monacantha (green) and Opuntia Ficus-indica (yellow). The purple variety had the highest yields (> 11kg/ m2). At the ripe stage, the juice recovery rate for the purple and yellow varieties was above 50%. The three varieties were a rich source of crude fiber (1.41-1.71g/ 100g), Potassium (106.21-203.71 mg/100g), Magnesium (62.9-123.86 mg/100g), and Zinc (2.30-2.39 mg/100g). The sugar content was predominantly glucose (1.26- 4.59 g/100g) and fructose (1.45-2.66 g/100g) with the yellow variety having the highest. The fruits exhibited substantial amount of total phenolics (1.79-2.52 g/100g G.A.E.) and high antioxidant activity (0.59-1.83 mg/ml), which was highest in the purple variety. Based on the sensory analysis, the yellow variety was considered best for fresh consumption. The purple variety had superior physicochemical characteristics suitable for commercial processing. The acceptability of the fruits and fruit-based products evaluated was above five (5) on a 9-point hedonic scale. This shows the potential of the fruits to be used either in isolation or with other food ingredients in the food industry.