The effects of micronutrient interventions on cognitive performance among school-aged children: A systematic review of RCTs

Abstract

Background/Aims: The prickly pear (PP) cacti (Opuntia ficus indica) are commonly utilised as a source of nutraceuticals due to its substantial bioactive composition. However, preservation of bioactivity can present a challenge with considerable losses of these compounds, depending on the type of drying technique used. Therefore, the aim of this study was to determine the optimum drying method to preserve the bioactive content of the commercially grown Australian PP's. Methods: Three PP varieties (White, Orange, Purple) were dried using four different Methods (freeze dryer, draft oven, microwave and dehydrator). Total Phenolic (Folin-Cioceultau; Gallic acid equivalent, GAE); Flavonoid (AlCl 3 ; Catechin equivalent, CE) and Betalain (Betaxanthin and Bethanin equivalent, BBE) content along with antioxidant characteristics (Trolox equivalent, TE), free radical scavenging activity (DPPH), reducing capacity (CUPRAC) and antioxidant capacity (FRAP) were determined spectropho-tometrically. Kendall's tau test was used to determine the best drying method in comparison to freeze drying. Results: Microwave drying produced the maximum levels for mean ± SEM total phenolic content in White (145.0 ± 15.5 mg GAE), Purple (129 ± 17.8 mg GAE) and Orange (138.7 ± 25.9 mg GAE) variety. In addition, in White and Purple variety, flavonoid (74.1 ± 8 mg CE and 66.2 ± 9.2 mg CE), CUPRAC (3261 ± 172.9 mM TE and 2743 ± 272.8 mM TE) and FRAP (1458.5 ± 32.3 mM TE and 1328 ± 146.3 mM TE) were also the highest. Total betalains, were highest in White PP (3.1 ± 0.5 mg BBE /100 g) following microwave drying, whereas Orange PP maximum was achieved using oven drying (3.2 ± 0.6 mg BEE /100 g) and Purple PP using dehydrator (2.9 ± 0.4 mg BEE /100 g); all p < 0.05. Conclusions: The method that preserved the highest amounts and activity of bioactives, during the drying process, in comparison to freeze-drying, was the microwave drying. Funding source(s): N/A