Identification of nutritional composition and antioxidant activities of fruit peels as a potential source of nutraceuticals

Abstract

Fruit peels comprise several biologically active compounds, but their nutritional composition and antioxidant potential of different fruit varieties are limited. This study aimed to determine the nutritional composition and antioxidant properties of 12 peels of different fruit varieties such as apples, pomegranates, guavas, strawberries, grapes, and citrus fruits using a ultraviolet-visible (UV-Vis) spectrophotometer, an inductively-coupled plasma atomic emission spectroscopy (ICP-AES), and an amino acid analyzer. The highest values of TPC, TFC, lycopene, ascorbic acid [total carotenoids and total antioxidant capacity (TAC)], reducing sugars, non-reducing sugars, and total soluble proteins were reported in grapes (Black seedless) 54,501.00 ± 0.82 μM/g dry wt., guava (Gola) 198.19 ± 0.46 Rutin equivalent dry wt., strawberry (Candler) 7.23 ± 0.33 mg/g dry wt., citrus (Mausami) 646.25 ± 0.96 ug/g dry wt., apple (Kala kulu-Pak) 14.19 ± 0.38 mg/g dry wt. and 12.28 ± 0.39 μM/g dry wt., strawberry (Candler) 25.13 ± 0.40 mg/g dry wt., pomegranate (Badana) 9.80 ± 0.43 mg/g dry wt., apple (Kala kullu-Irani) 30.08 ± 0.11 mg/g dry wt., and guava (Gola) 638.18 ± 0.24 mg/g dry wt. compared with its opponent peels of fruits, respectively. All 12 peels of the fruit verities had 20 amino acids and presented as dry matter basis%. The highest trend of glutamic acid + glutamine, glycine, and aspartic acid + asparagine was observed in pomegranate (Badana) 1.20 DM basis%, guava (Surhai and Gola) 1.09 and 1.09 DM basis%, and strawberry (Desi/local and Candler) 1.15 and 1.60 DM basis% in response to other fruit peels, respectively. Regarding the mineral profile, the highest values of nitrogen (764.15 ± 0.86 mg/100 g), phosphorus (53.90 ± 0.14 mg/100 g), potassium (3,443.84 ± 0.82 mg/100 g), ferric (1.44 ± 0.00 mg/100 g), magnesium (1.31 ± 0.00 mg/100 g), and manganese (0.21 ± 0.00 mg/100 g) were found in pomegranate (Badana), grapes (Black seedless), apple (Kala kulu-Pak), and pomegranate (Badana), respectively, in context to other fruit peels’ extract. Principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were analyzed for determining the correlation among different peels of fruits. Significantly, high levels of variation were noticed among different variables of peels of fruit. Fruit variety and its peels have been distinctive variables in selecting genotypes. The dendrogram obtained from cluster analysis was distributed into two groups and consisted of eight varieties in the same group, and four fruit varieties were in second group. Overall, the results conclude that fruit peels have the abundant antioxidants and some minerals, which can effectively be utilized for nutraceuticals as well as for food security.

Transcriptome and UPLC-MS/MS reveal mechanisms of amino acid biosynthesis in sweet orange ‘Newhall’ after different rootstocks grafting

“…Previous studies discovered 38 AAs in different tissues of citrus, such as flesh, peel, leaf and phloem ( Matsumoto and Ikoma, 2012 ; Setamou et al., 2017 ; Sheng et al., 2017 ; Hussain et al., 2022 ). In our experiment, a total of 110 kinds of AA were detected, including 5 essential AAs.…”

“…Citrus peel extracts, such as flavonoids, coumarins, terpenes and alkaloids, have been proved to have antibacterial and anti-inflammatory effects, and AAs also have pharmacological effects ( Singh et al., 2020 ; Fei et al., 2022 a; Hussain et al., 2022 ). Due to the lack of in-depth research on citrus AAs, there are few foods or drugs in the market that use AAs in citrus peel as raw materials, so the research on the composition and content of AAs in citrus peel is particularly important.…”

Effects of Pre-Harvest Spraying with Salicylic Acid (SA) and Sodium Nitroprusside (SNP) on Storage Quality and Pathogenic Fungal Species in ‘Manaohong’ Cherries

“…The supernatant of the fruit extract was mixed with 1.0 mL of Coomassie brilliant blue dye and measured at 595 nm. The content was calculated using bovine serum albumin as the standard [27]. The total phenolic content in cherry fruit was determined using the Folin-Ciocalteu method [28].…”

Enhancing bioactive content in Malus sylvestris peel extract for antioxidant source using microwave-assisted extraction (MAE) and predicting the potential of ant nests

“…1 Apples contain antioxidant compounds that protect the body from damage caused by free radicals. 2,3 Afsharnezhad, M., Shahangian, S. S., Panahi, E., & Sariri, R. (2017). Free radicals are unstable molecules that can damage body cells and cause various chronic diseases, including cancer, heart disease, diabetes, and premature aging.…”