The phenolics, antioxidant activity and in vitro digestion of pomegranate (Punica granatum L.) peels: an investigation of steam explosion pre-treatment

Abstract

Pomegranate peels, the main byproduct of pomegranate production, are rich in phenolic compounds that are known for their effective antioxidant properties and have vast application prospects. In this study, steam explosion, an environmentally friendly technique, was applied to pretreat pomegranate peels for phenol extraction. We investigated the effects of explosion pressure, duration, and particle size on the content of total and individual phenolics, and antioxidant activity of pomegranate peels before and after in vitro digestion. The optimal conditions for a steam explosion for pomegranate peels in terms of total phenol content were a pressure of 1.5 MPa, a maintenance time of 90 s, and a particle size of 40 mesh. Under these conditions, pomegranate peel extract presented a higher yield of total phenols, gallic acid, and ellagic acid. However, it also had a lower content of punicalin and punicalagin, compared to the unexploded peels. There was no improvement in the antioxidant activity of pomegranate peels after the steam explosion. Moreover, the content of total phenol, gallic acid, ellagic acid, punicalin, and punicalagin, as well as the antioxidant activity of pomegranate peels, all increased after gastric digestion. Nevertheless, there was a large variation in the pomegranate peel processed by different pressure, duration, and sieve fractions. Overall, this study demonstrated that steam explosion pre-treatment could be an efficient method for improving the release of phenolics, especially gallic acid, and ellagic acid, from pomegranate peels.

Effect of steam explosion on the morphological, textural, and compositional characteristics of betel nut

“…As observed in the microscopic structure, another possible explanation is that the steam explosion treatment leads the otherwise smooth and firm epidermis to become rough and loose. Wang et al (2023) found that the surface of pomegranate peels became rough and wrinkled after steam explosion by observing the microstructure.…”

Multichromosomal Mitochondrial Genome of Punica granatum: Comparative Evolutionary Analysis and Gene Transformation from chloroplast genomes

“…The consumption of pomegranates has shown a remarkable increase due to their exceptional economic, nutritional, medicinal and ornamental value. The different parts (fruit peel, juice, seeds, owers, leaves, bark) are rich in bioactive constituents, and have various medicinal advantages to provide high antioxidant, antineoplastic, anticancer and phytonutrient capacity [6][7][8][9]. At present, pomegranate related industries are expanding rapidly, and plays an important role in the economic, cultural and ecological elds.…”

Comparative analysis of the phenolic contents and antioxidant activities of different parts of two pomegranate (Punica granatum L.) Cultivars: ‘Tunisia’ and ‘Qingpi’

“…Pomegranate (Punica granatum L.) is a small arbor or shrub belonging to the family Lythraceae. It is used for both food and medicinal purposes (Zhao and Yuan, 2021;Wang et al, 2023). Pomegranate is known for its strong antioxidant properties due to its abundant phenolic compounds, and it has been traditionally used for preventing and treating various diseases, such as heart disease and diabetes (Asgary et al, 2014;Bahmani et al, 2014;Asgharpour and Alirezaei, 2021).…”

“…Flavanols exhibit antioxidant, anti-tumor, anti-inflammatory, and antimicrobial effects (Kopustinskiene et al, 2020;Chagas et al, 2022). Anthocyanins, on the other hand, are edible polyphenolic pigments with strong free radical scavenging ability and anti-cancer properties (Silva et al, 2017;Wang et al, 2023). Indicators such as total polyphenol content (TPC), total flavonoid content (TFC), total flavanol content (TFAC), and total anthocyanin content (TMAC) are often used to assess the antioxidant properties of plants.…”