Variation in Phytochemical, Antioxidant and Volatile Composition of Pomelo Fruit (Citrus grandis (L.) Osbeck) during Seasonal Growth and Development

Abstract

Citrus fruits exhibit a high level of different phytoconstituents, of which the changes in the different parts of the fruit during ripening have not been thoroughly studied yet. Thus, in this study, we have investigated how different parts of pomelo fruit (Citrus grandis L.) are modified throughout the development of two consecutive growing seasons. In detail, the main phytochemical compounds, such as total phenolic content, total flavonoid content, antioxidant capacity, DPPH free radical scavenging activity, Ferric reducing antioxidant power (FRAP), and naringin and tannin content, were analyzed. A systematic metabolism of these compounds was found during the development of the fruit, but some pomelo tissues showed a fluctuating trend, suggesting a dependence on the different growing season. Focusing on the tissue distribution of these compounds, the fruit membrane contained the highest level of total phenolic and flavonoid content; fruit flavedo displayed the highest antioxidant capacities and FRAP activities, whereas maximum accumulation of naringin was noticed in fruit albedo. Instead, the highest DPPH free radical scavenging activity and tannin contents were found in the pomelo juice. Regarding the distribution of compounds, a possible bias pattern for the accumulation of those compounds has been noticed throughout the fruit development. From the GC-MS analysis, a total of 111 compounds were identified, where 91 compounds were common in both seasons. Overall, these results could be useful for the food processing industry as guidelines for excellent quality foods and for introducing health-beneficial products and components into our daily diets.

Metabolomic Profiling of Citrus unshiu during Different Stages of Fruit Development

“…This result indicated that immature fruits are suitable for the production of citrus products having high antioxidant activity. Similar results have been observed during fruit development stages in various citrus fruits, including Pomelo [ 24 ], sweet orange [ 27 ], Chinese native cultivars [ 28 ], and Navel orange [ 29 ]. The decrease in phenolic compounds according to the fruit development led to a decrease in their antioxidant activities.…”

“…In addition, flavonoids (quercetin triglucoside, saponarin, quercetin triglucoside derivatives, kaempferol triglucoside, hesperetin triglucoside, kaempferol-3-rutinoside, isorhamnetin-3-rutinoside, narirutin, hesperidin, didymin, nobiletin, methoxynobiletin, and tangeretin), volatile compounds (α-pinene, β-pinene, α-terpinene, limonene, γ-terpinene, α-terpinolene, linalool, 4-terpineol, α-terpineol, decanal, δ-elemene, α-cubebene, texanol, α-copaene, β-elemene, γ-elemene, α-humulene, germacrene D, α-farnesene, and δ-cadinene), limonoids (zapoterin, xylogranatin K, nomilin, and limonin), and carotenoids (β-carotene and β-cryptoxanthin) were identified as the secondary metabolites. Similar metabolite profiles have also been observed during fruit development in other citrus varieties, including Navel orange [ 8 ], Ponkan [ 10 ], Persian Lime [ 11 ], and Pomelo [ 24 ].…”

“…The highest content was observed on Nov. 16 (30.09 mg β-carotene equivalent [βCE]/100 g), and the content was 4.3 times higher than that on Aug. 1 (6.93 mg βCE/100 g fresh sample). The decrease in TPC during citrus fruit development could be correlated with the increased activity of polyphenol oxidase (PPO), owing to an increase in fruit pH [ 23 ] and a decrease in the activity of phenylalanine ammonia lyase, a key enzyme of the phenylpropanoid pathway for the biosynthesis of phenolic compounds during citrus fruit development [ 24 ]. By contrast, an increase in TCC might a result of an increase in the expression of carotenoid synthesis genes such as CitPSY, CitPDS, CitZDS, CitLCYb, CitHYb, and CitZE, which are involved in carotenoid accumulation [ 25 , 26 ].…”

Physiological and Qualitative Response of Cucurbita pepo L. to Salicylic Acid under Controlled Water Stress Conditions

“…C. pepo seeds oil has no cholesterol, and is rich in ω9, and ω6 acids, fatty acids with more than 40% oleic acid, 33.1% linoleic acid, and 14.7% palmitic acid, and is effective in relieving joint pain, especially in chronic conditions and post-menopausal bone density [2,3]. The quantity, and quality of secondary metabolites such as alkaloids, glycosides, steroids and, essential oils in medicinal plants are affected by environmental factors including drought stress, nutrition, and plant growth regulators [4][5][6][7][8][9][10][11][12][13][14].…”

Physiological, Biochemical, and Agronomic Trait Responses of Nigella sativa Genotypes to Water Stress

“…[7,17]. Several studies have also shown that drought had beneficial impacts on secondary metabolite biosynthesis, solute accumulation, and enzyme activity [5,[8][9][10][18][19][20][21][22]. Cultivation of drought-tolerant genotypes of medicinal and aromatic plant species, on the other hand, could be another way to address water scarcity issues.…”