Potential Natural Dyes Food from the Powder of Prickly Pear Fruit Peels (Opuntia spp.) Growing in the Mediterranean Basin under Climate Stress

Abstract

Background. Barbary fig (Opuntia spp), called prickly pear, is a cultivated species belonging to family Cactaceae. It produces fruits one time per year during a short season. It is largely spreading in the Mediterranean countries. The aim of the study was to investigate the physicochemical and biochemical analysis of powder of prickly pear fruit peels of three Moroccan varieties (Aakria, Derbana, and Mles). Material and Methods. Both physicochemical analysis (humidity, water activity, Brix, ash content, pH, and total titratable acidity) and biochemical analysis (total carotenoid content, betalain content, total polyphenolic content, and ascorbic acid content) were effectuated according to protocols reported within the present research work. Results. Regarding the physiochemical analysis, the humidity of powder of prickly pear fruit peels ranged from 10.173 ± 0.002 to 15.27 ± 0.02%. The water activity (aw) ranged from 0.17 ± 0.002 to 0.336 ± 0.002. The values of Brix ranged from 68.67 ± 0.33 to 74.22 ± 0.51° Bx. pH values ranged from 5.41 ± 0.01 to 5.62 ± 0.01. The total titratable acidity values ranged from 0.644 ± 0.014 to 0.76 ± 0.007 g citric acid/100 g DM (dry matter). The ash content ranged from 1.02 ± 0.02 to 11.41 ± 0.03 g/100 g DM. Regarding the biochemical analysis, the total carotenoid content ranged from 5.14 ± 0.10 to 9.79 ± 0.06 mg/g of FM (Fresh matter). The total betalain content ranged from 2 ± 0.69 to 37.66 ± 2.65 mg/100 g of DM. The total polyphenolic content ranged from 1739.92 ± 13.69 to 2409.66 ± 43.65 mg gallic acid equivalent (GAE)/100 g of DM. The ascorbic content values ranged from 186.78 ± 13.23 to 294.04 ± 5.81 mg/100 g of DM. Conclusion. The results showed an interesting richness of the investigated powder in pigments (betacyanins, indicaxanthins, and carotenoids) and nutritional compounds including sugar, proteins, and vitamins that make this powder interesting for being used as a dye in food.