Phenolic Compounds and Antioxidant Activity of Sprouts from Seeds of Citrus Species

Abstract

Seeds from Citrus species represent a relevant by-product of the juice industry and a potential source of bioactive compounds such as phenols and other antioxidants. Sprouting could be an intriguing idea to enhance the content of these compounds, as explored for other fruittree species. In this experiment, the sprouting performance, the concentration of total phenols and phenolic acids, and the antioxidant activity of seeds and sprouts were evaluated for bitter orange (Citrus aurantium L. seedlings), blonde orange (Citrus sinensis (L.) Osbeck cv.Biondocomune), sweet orange (Citrus sinensis (L.) Osbeck seedlings), lemon (Citrus limon (L.) Osbeck cv.Femminello), and mandarin (Citrus reticulata Blanco cv.Tardivo di Ciaculli). The germination was high for all genotypes except for mandarin, but it took 4–8 weeks. Sprouts did not differ among genotypes for size and generally had hard consistency of cotyledons and a bitter taste. The concentrations of total phenols and phenolic acids of seeds and sprouts varied with the genotype, while the antioxidant activity was not statistically different among treatments. Sprouting increased both the concentration of phenolic compounds and antioxidant activity but no correlation was found between them, suggesting that other antioxidants, besides phenols, are present. Given the slow germination and the bitter taste, Citrus sprouts appear unsuitable for homemade production aimed at direct consumption, while they may have perspectives for extraction of food additives, cosmetics, and pharmaceutics.

Antioxidant and antimicrobial effects of gelatin films incorporated with citrus seed extract on the shelf life of sea bass ( Dicentrarchus labrax ) fillets

“…In the present study, the TPCs were found as 343.70 mg GAE/100 g and 332.28 mg GAE/100 g in OSE and LSE, respectively. The TPC of CSE determined in this study was higher than those reported by previous studies (Aishwarya Reddy et al., 2018; Anagnostopoulou et al., 2006; Falcinelli et al., 2020). Anagnostopoulou et al.…”

“…(2006) notified that the TPC of orange peel extract ranged between 3.0 and 105 mg GA/g dry extract while Falcinelli et al. (2020) found the TPC of lemon and bitter orange seeds extract ranged between 1.2 and 2.5 mg GAE/g dry weight. The TPC of citrus species depends on several factors such as the origin of species, extraction temperature and time, extraction solvent.…”

Citrus aurantium L. Active Constituents, Biological Effects and Extraction Methods. An Updated Review

“…Phenolic acids included gallic acid, vanillic acid, syringic acid, rosmarinic acid, p-coumaric acid, and trans-2-hydroxycinnamic acid. A more recent study investigating the concentration of phenolic compounds present in different Citrus seeds corroborates these findings [22]. Phenolic acids found in bitter orange seeds belong to the hydroxybenzoic acids (vanillic acid, 3.3 µg/g DW) and hydroxycinnamic acids (caffeic acid, 5 µg/g DW; trans-ferulic acid, 3 µg/g DW; and p-coumaric acid, 15 µg/g DW) families [22].…”

Citrus species: Modern functional food and nutraceutical-based product ingredient

“…Bitter orange, blonde orange, sweet orange, lemon, and mandarin seed ultrasound methanol extracts (Table 3) were investigated for their antioxidant ability but no differences were found in the radical scavenging activity (Falcinelli et al, 2020). Conversely, Costanzo et al (2020) demonstrated that powered Citrus reticulata seed extract tissue showed the highest antioxidant capacity (55.6 mmol TE/mg FW) compared to Citrus japonica seed extract tissue (3.2 mmol TE/mg FW).…”