UPLC-QTOF-MSE based metabolomics and chemometrics study of the pitaya processing.

The search for knowledge related to the Pitaya (Hylocereus polyrhizus [F.A.C. Weber] Britton & Rose, family Cactaceae) is commonly due to its beneficial health properties e aesthetic values. But process to obtain pitaya pulp is a first and important step in providing information for the subsequent use of this fruit as colorant, for example. Therefore, the effects of the pulping process on the metabolomic and chemometric profile of non-volatile compounds of pitaya were assessed for the first time. The differences in metabolic fingerprints using UPLC-QTOF-MSE and multivariate modeling (PCA and OPLS-DA) was performed in the following treatments: treatment A, which consists of pelled pitaya and no ascorbic acid addition during pulping; treatment B, use of unpelled pitaya added of ascorbic acid during pulping; and control, unpelled pitaya and no ascorbic acid addition during pulping. For the metabolomic analysis, UPLC-QTOF-MSE shows an efficient method for the simultaneous determination of 35 non-volatile pitaya metabolites, including isorhamnetin glucosyl rhamnosyl isomers, phyllocactin isomers, 2'-O-apiosyl-phylocactin and 4'-O-malonyl-betanin. In addition, the chemometric analysis efficiently distinguished the metabolic compounds of each treatment applied and shows that the use of unpelled pitaya added of ascorbic acid during pulping has an interesting chemical profile due to the preservation or formation of compounds, such as those derived from betalain, and higher yields, which is desirable for the food industry.

Effects of processing on the chemical, physicochemical, enzymatic, and volatile metabolic composition of pitaya (Hylocereus polyrhizus (F.A.C. Weber) Britton & Rose).

The effects of processing on the chemical, physicochemical, enzymatic, and volatile metabolic composition of pitaya pulp were assessed for the first time. To this end, the following treatments to obtain pitaya pulp were evaluated: Treatment A (TA, pulp processing without ascorbic acid), Treatment B (TB, whole fruit processing with ascorbic acid), and Control (whole fruit processing without ascorbic acid). The treatment employed in TB resulted in low polyphenol oxidase and peroxidase activity, and no significant chemical or physicochemical alterations in most parameters evaluated. In addition, TB presents high yields and fiber content compared to the TA or Control. For metabolic analysis, Gas Chromatography-Mass Spectrometry (GC-MS) was effective for the simultaneous determination of 80 volatile metabolites in pitaya. Chemometric analyses was used to efficiently distinguish the volatile compounds of each treatment, and demonstrated that TB presents an interesting volatile profile due the conservation or agregation of compounds.

Metabolic profile of pitaya (Hylocereus polyrhizus (F.A.C. Weber) Britton & Rose) by UPLC-QTOF-MSE and assessment of its toxicity and anxiolytic-like effect in adult zebrafish.

Pitaya is a Cactacea with potential for economic exploitation, due to its high commercial value and its functional components - such betalains, oligosaccharides and phenolic compounds. Although the biological activities of pitaya have been studied using in vivo and in vitro models (anti-inflammatory and antiproliferative activities, as example), its anxiolytic-like effect is still unexplored. Therefore, the aim of this work was to perform a characterization of pulp and peel of pitaya (Hylocereus polyrhizus (F.A.C. Weber) Britton & Rose) using UPLC-QTOF-MSE, and to assess its toxicity and anxiolytic-like effect in adult zebrafish (Danio rerio). The results showed 16 and 15 compounds (in pulp and peel, respectively), including maltotriose, quercetin-3-O-hexoside, and betalains, putatively identified by UPLC-QTOF-MSE. Thus, pitaya pulp and peel showed no toxicity in both models tested (Vero cell lines and zebrafish model, LC50 ˃ 1 mg/mL); and a significant anxiolytic activity, since the treated fish reduced the permanence in the clear zone (Light & Dark Test) compared to that in the control, exhibiting anxiolytic-simile effect of diazepam. However, these effects were reduced by pre-treatment with the flumazenil suggesting that the pulp and peel of pitaya are anxiolytics agents mediated via the GABAergic system. These findings suggested that H. polyrizhus has the potential of developing an alternative plant-derived anxiolytic therapy. In addition, pitaya peel (which is a waste in the food industry) should be regarded as a valuable product, which has the potential as an economic value-added ingredient for anxiety disorders.