Antioxidant Content, Capacity and Retention in Fresh and Processed Cactus Pear (Opuntia ficus-indica and O. robusta) Fruit Peels From Different Fruit-Colored Cultivars

Abstract

During processing, the peels and seeds from cactus pear fruits are usually discarded. These "waste" products contain valuable bioactive compounds. This study investigated the antioxidant content and antioxidant potential of fresh and processed (juiced, dried, preserved, and chutney) cactus pear fruit peels from different fruit-colored cactus pear cultivars. Cactus pear peels contained high levels of antioxidants and demonstrated high antioxidant activity. The highest contents were found in dried peels, while the preserves had the lowest contents. Products on the positive side of Factor 1 of the PCA plot are mostly associated with the antioxidants PCA analysis showed that products, rather than cultivars, seem to cluster together, e.g., juices and fresh peels, chutneys, preserves and dried peels. Robusta and its products cluster together, as well as with betalains. The % DPPH, carotenoids and phenolics are grouped together, with % chelating activity closely correlated with ascorbic acid. Dried products from all cultivars correlated closely with % DPPH, carotenoids and phenolics, especially dried peel from Gymno-Carpo (orange), Ofer (orange), Meyers (red), and Nepgen (green). Red and orange preserves formed a cluster, while green preserves and chutney from all cultivars clustered together, as did fresh peels and juices. Purple fruit peel products had the highest % DPPH, % chelating activity, betalains, phenolic compounds and carotenes. Ascorbic acid dominated in orange and red fruit peels. Purple and orange were the colors of cactus pear fruit cultivars that might be the best choice in terms of antioxidant content. The cultivar that presented the best fruit peel from an antioxidant point of view for preservation was Robusta. Cactus pear fruit peels should be included in processed products such as juice, dried fruit and chutneys. These processed products are multi-component food ingredients and are therefore multi-component nutraceuticals which retained their antioxidant properties.

Hepatoprotective Effect of Opuntia robusta Fruit Biocomponents in a Rat Model of Thioacetamide-Induced Liver Fibrosis

“…Or has proven to be the species with the highest concentration of betalains, total phenolic compounds and flavonoids [ 11 , 12 ], which confirms its important biological activities, mainly its antioxidant capacity. We propose that their consumption reduces the severity of liver fibrosis.…”

“…Opuntia species have many benefits, and their widespread distribution has prompted research on the nutritional properties of their fruits, the prickly pears [ 7 , 8 ], which have been proposed as functional foods. Concentrations of various bioactive compounds have been reported before, mainly betacyanins, total phenols and flavonoids in seeds [ 9 ], peel [ 9 , 10 , 11 ], pulp [ 9 , 11 ], and juice [ 12 ] of different species of this genus. However, the fruits of each harvest have different concentrations of secondary metabolites since these depend on external environmental conditions and stimuli, such as humidity, temperature, season, altitude, pollution, etc.…”

Phenolic composition, antioxidant and antiacetylcholinesterase activities of Opuntia ficus‐indica peel and flower teas after in vitro gastrointestinal digestion

“…27 The mean value of carotenoids (0.017 g kg −1 ) reported for the Opuntia peels were higher than that reported for the Opuntia pulp carotenoid value (0.004 g kg −1 ). 28 Comparing carotenoids of the fresh fruit (pulp), peel, seeds and cladodes of each cultivar, very low levels were found in fruit pulp and peel, and high levels in seeds. 29…”

Vinegar production via spontaneous fermentation of different prickly pear fruit matrices: changes in chemical composition and biological activities

“…However, most of the published works on different varieties of PP show that they are mainly composed of 85% water and between 8.1% to 17% total sugars (especially glucose and fructose). They also contain around 5.83% total dietary fibers, 1.6% protein, 3.4% ash, and 0.83% fatty acids 10,11 . Several studies have highlighted the peculiar properties of PP as a source of bioactive compounds, such as vitamins C and E, polyphenols, carotenoids, flavonoids, taurine, and pigments 12 .…”

“…They also contain around 5.83% total dietary fibers, 1.6% protein, 3.4% ash, and 0.83% fatty acids. 10,11 Several studies have highlighted the peculiar properties of PP as a source of bioactive compounds, such as vitamins C and E, polyphenols, carotenoids, flavonoids, taurine, and pigments. 12 Prickly pear has gained widespread popularity as a functional food and nutraceutical source.…”