Characterization, Stability, and Bioaccessibility of Betalain and Phenolic Compounds from Opuntia stricta var. Dillenii Fruits and Products of Their Industrialization

Abstract

The aim of the present study was the full characterization, quantification, and determination of the digestive stability and bioaccessibility of individual betalain and phenolic compounds of Opuntia stricta, var. Dillenii fresh fruits (peel, pulp, and whole fruit) and of the products of the industrialization to obtain jam (raw pressed juice (product used for jam formulation), by-product (bagasse), and frozen whole fruit (starting material for jam production)). Opuntia stricta var. Dillenii fruits and products profile showed 60 betalain and phenolic compounds that were identified and quantified by HPLC-DAD-ESI/MS and HPLC-DAD-MS/QTOF, being 25 phenolic acids (including isomers and derivatives), 12 flavonoids (including glycosides), 3 ellagic acids (including glycosides and derivative), and 20 betanins (including degradation compounds). In vitro gastrointestinal digestion was performed by INFOGEST® protocol. Fruit pulp showed the greater content of total betalains (444.77 mg/100 g f.w.), and jam only showed very low amounts of two betanin degradation compounds, Cyclo-dopa-5-O-β-glucoside (and its isomer) (0.63 mg/100 f.w.), and two Phyllocactin derivatives (1.04 mg/100 g f.w.). Meanwhile, fruit peel was the richer tissue in total phenolic acids (273.42 mg/100 g f.w.), mainly in piscidic acid content and total flavonoids (7.39 mg/100 g f.w.), isorhamnetin glucoxyl-rhamnosyl-pentoside (IG2) being the most abundant of these compounds. The stability of betalains and phenolic compounds during in vitro gastrointestinal digestion is reported in the present study. In Opuntia stricta var. Dillenii pulp (the edible fraction of the fresh fruit), the betanin bioaccessibility was only 22.9%, and the flavonoid bioaccessibility ranged from 53.7% to 30.6%, depending on the compound. In non-edible samples, such as peel sample (PE), the betanin bioaccessibility was 42.5% and the greater bioaccessibility in flavonoids was observed for quercetin glycoside (QG1) 53.7%, the fruit peel being the most interesting material to obtain antioxidant extracts, attending to its composition on antioxidant compounds and their bioaccessibilities.

Ultrasound-Assisted “Green” Extraction (UAE) of Antioxidant Compounds (Betalains and Phenolics) from Opuntia stricta var. Dilenii’s Fruits: Optimization and Biological Activities

“…All physicochemical analysis was conducted as reported by Gómez-López et al [ 6 ]. pH and soluble solids were measured from fresh pulp fruit puree.…”

“…The extraction of betalains and phenolic compounds for HPLC analysis of the Opuntia material (whole fruits) was performed following the procedure reported by Gómez-López et al [ 6 ]. This method is the conventional procedure to obtain extracts without the use of ultrasound.…”

“…Betalains and phenolic compounds were simultaneously determined according to the method reported by our research group [ 6 ]. A 1200 Series Agilent HPLC System (Agilent technologies, Santa Clara, CA, USA) with a C18, reverse column (Zorbax SB-C18, 250 4.6 nm i.d., S-5 µm; Agilent) at 25 °C was employed.…”

“…Opuntia stricta var. Dillenii ’s prickly pear fruit is also rich in phenolic compounds, such as piscidic acid and flavonoids, mainly isorhammentin glucoxyl-rhamnosyl-pentoside (IG2) [ 6 , 7 ].…”

“…Nowadays, consumer demand for healthy and functional foods is increasing. Gómez-López et al [ 6 ] reported that the Opuntia stricta var. Dillenii whole fruits are an interesting starting material to obtain antioxidant compounds regarding not only their betalain and phenolic compound profile, but the stability and bioaccessibility of these bioactives during in vitro gastro-intestinal digestion.…”