The Effect of Juicing Methods on the Phytochemical and Antioxidant Characteristics of the Purple Prickly Pear (<i>Opuntia ficus indica</i>)—Preliminary Findings on Juice and Pomace

Abstract

Prickly Pear (PP) is often overlooked due to its’ short shelf-life. Juicing may improve marketability but often affects quality, thereby warranting investigation. Purple PP (whole (WF) and flesh (FF)) was juiced using blenders; stick (SB) and jug (JB); and juicers; commercial (CJ) and cold-pressed (CP). Juices and methanolic (70%) pomace extracts were analysed for; bioactives; Total Phenolic (TPC; µgGAE/mL), Flavonoid (TFC; µgCE/mL) and Betalain Content (TBC; mg/100 g; Betacyanin; BE; Betaxanthin; IE); and antioxidant characteristics; DPPH, FRAP (µMTE) and vitamin C (mgAAE/mL). Juicing techniques had effects on phytochemicals in; juice: TPC (WF/FF; p = 0.022–0.025), TFC (FF; p = 0.034), Betacyanin (WF/FF; p = 0.029–0.026), FRAP (WF/FF; p = 0.016–0.024) and Vitamin C (WF/FF; p = 0.015–0.016); and pomace: TPC (WF/FF; p = 0.015), TBC (FF; p = 0.034), Betacyanin (FF; p = 0.047), Betaxanthin (FF; p = 0.017), DPPH (WF/FF; p = 0.016–0.024), FRAP (WF/FF; p = 0.015–0.023) and Vitamin C (WF/FF; p = 0.016–0.022). Processing-style (blend/juice) affected; TPC, DPPH and FRAP in juice and pomace. Overall, fruit-preparation (WF/FF) had minimal effects. Additionally, correlations existed between; juice TFC and TBC (p = 0.001; τ = −0.044); TBC and vitamin C (p = 0.001; τ = −0.637); pomace TPC and DPPH (p = 0.003; τ = 0.440), TPC and vitamin C (p = 0.011; τ = 0.440); and TFC and FRAP (p = 0.001; τ = 0.519). The best methods overall for juice were SB (FRAP), JB (TPC, TBC), CJ (TFC) and CP (DPPH, VitC); and for pomace extracts; SB(FRAP), JB (TPC, VitC), CJ(TFC), and CP (TBC, DPPH).

Keywords

• juice
• phytochemical
• <i>Opuntia ficus indica</i>
• Prickly Pear
• cold pressed