Optimization of a polyphenol extraction method for sweet orange pulp (Citrus sinensis L.) to identify phenolic compounds consumed from sweet oranges

Abstract

The consumption of sweet oranges has been linked to several health benefits, many of which are attributed to hesperidin, a flavanone that is present in high amounts in these fruits. However, other phenolic compounds can contribute to the bioactivity of sweet orange. To link those effects to their phenolic profile, the complete characterization of the phenolic profile is mandatory. Although many studies have profiled the phenolic composition of orange juices, their pulps, which retain phenolic compounds, are overlooked. This fact is particularly relevant because dietary guidelines recommend the consumption of whole fruits. Therefore, this study aimed to develop a specific method for the optimal extraction of phenolics from orange pulp and to use this method to characterize these fruits grown at different locations by HPLC-ESI-MS/MS. The extraction conditions that reported the highest total polyphenol content (TPC) and hesperidin contents were 20 mL/g, 55 °C, and 90% methanol. The extraction time and number of sequential steps were further evaluated and optimized as 20 min and two extraction steps, respectively. Although lower extraction rates were achieved when using ethanol as the extraction solvent, high TPC and hesperidin yields were obtained, suggesting the potential use of this methodology to produce phenolic-rich extracts for the food industry. By applying the optimized methodology and analyzing the extracts by HPLC-ESI-MS/MS, geographic cultivation regions were demonstrated to affect the phenolic profiles of oranges. In short, we developed a quick, easy-to-perform methodology that can be used to extract orange phenolics from pulp for their identification and quantification and to evaluate the factors that affect the phenolic profile in sweet orange pulps.

Peel of Traditional Apple Varieties as a Great Source of Bioactive Compounds: Extraction by Micro-Matrix Solid-Phase Dispersion

“…A graphical representation of such parabolic behavior is shown in Figure 4. The observed behavior was previously reported by Álvarez-Casas et al [33], who optimized the process of pressurized solvent extraction of polyphenolic compounds from white grape marc, as well as Assefa et al [34], who studied the extraction of antioxidants and flavonoids from yuzu peel (Citrus junos Sieb ex Tanaka) and Iglesias-Carres et al [32], who optimized the process of polyphenol extraction from sweet orange pulp. The same negative quadratic effect was found for flavonoles regarding extract volume ( Table 3).…”

“…Regarding the extraction volume, the linear positive effect was found to have a significant influence on the investigated responses. The linear positive effect indicates that increasing the particular factor will result in greater yields of the observed response, which in this case means that increasing the volume of the extract will result in greater yields of all polyphenol groups [32]. Dispersant mass was not significant for the polyphenol yields.…”

Consumption of out-of-season orange modulates fat accumulation, morphology and gene expression in the adipose tissue of Fischer 344 rats

“…The most prominent phenolic compound of both oranges was hesperidin (38.28 × 10 3 mg/ kg dry weight (dw) for ON and 25.83 × 10 3 mg/kg dw for OS), followed by narirutin (8.07 × 10 3 mg/kg dw for ON and 3.54 × 10 3 mg/kg dw for OS). Other compounds such as didymin, kaempferol-3-O-rutinoside, protocatechuic acid O-glucoside, among others, were also found in relevant concentrations and in accordance to the characterization of other sweet orange varieties [20].…”

“…For frequencies, adipocytes were distributed in two groups according to their area (< 5000 or > 5000 µm 2 ). Data are presented as the mean ± SEM and statistical significance is analysed by one-way ANOVA (p < 0.05) followed by Duncan's new multiple range (MRT) post hoc test different environmental conditions in which both oranges were harvested [20]. Thus, we believe that these differences in composition could be the ones responsible, together with the photoperiod, of the observed changes.…”

“…Afterwards, the powder was stored at room temperature and protected from light until use. The characterization of both sweet oranges used in this experiment was performed using an HPLC-ESI-MS/MS methodology, and is described by Iglesias-Carres et al [20]. The most prominent phenolic compound of both oranges was hesperidin (38.28 × 10 3 mg/ kg dry weight (dw) for ON and 25.83 × 10 3 mg/kg dw for OS), followed by narirutin (8.07 × 10 3 mg/kg dw for ON and 3.54 × 10 3 mg/kg dw for OS).…”