Abstract
The utilization of fruit by-products in bakery products has gained increasing attention due to their nutritional and functional potential. This study investigated the nutritional composition, and functional properties of grapefruit wall material and to evaluate its impact on bread quality. In the first phase the nutritional composition (including moisture, ash, protein, fat, fiber and total carbohydrates) of grapefruit peel powder was determined following the methods given in AACC. Then, in the second phase wall material was extracted using the alkali extraction method and characterized for the determination of structure through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, the flavonoid and phenolic content were quantified, and antioxidant activity was evaluated through DPPH and FRAP. In the last phase, bread was prepared using different concentrations of wall material (T0, T1, T2 = 0 g, 2 g, and 4 g) to evaluate its effects on texture, color, and sensory attributes. Initially, chemical composition of grapefruit peels revealed 76% moisture, 0.81% ash, 6.04% crude fat, 2.56% crude protein, 6.96% crude fiber, and 8.17% nitrogen-free extract. The results showed that increased wall material reduced hardness and chewiness but enhanced cohesiveness, springiness, and adhesiveness after two days of storage. Higher GFWM concentrations also decreased L* values, resulting in darker bread color. Bread prepared with the treatment (T2) achieved the highest sensory acceptability. The incorporation of GFWM enhanced the nutritional and textural qualities of bread, showing its potential as a functional ingredient in cereal-based formulations.
Similar content being viewed by others
Data availability
Even though adequate data has been given in the form of tables and figures, however, all authors declare that if more data is required then the data will be provided on a request basis from Catherine Tamale Ndagire.
References
Committee, A. Approved methods of the American association of cereal chemists Vol. 1 (American Association of Cereal Chemists, 2000).
Luro, F. et al. Diversity of pummelos (Citrus maxima (Burm.) Merr.) and grapefruits (Citrus x aurantium var. paradisi) inferred by genetic markers, essential oils composition, and phenotypical fruit traits. Plants 14(12), 1824 (2025).
Louzada, E. S. & Ramadugu, C. Grapefruit: History, use, and breeding. HortTechnology 31(3), 243–258 (2021).
Chaudhary, S. & Singh, B. Grapefruit peel waste: Unlocking the potential for industrial applications in the circular economy: S. Chaudhary. Food Sci. Biotechnol. 34(10), 2131–2155 (2025).
Rifna, E., Misra, N. & Dwivedi, M. Recent advances in extraction technologies for recovery of bioactive compounds derived from fruit and vegetable waste peels: A review. Crit. Rev. Food Sci. Nutr. 63(6), 719–752 (2023).
Gong, H. et al. Separation, purification, structure characterization, and immune activity of a polysaccharide from Alocasia cucullata obtained by freeze-thaw treatment. Int. J. Biol. Macromol. 282, 137232 (2024).
Mruthunjaya, K. et al. Valorization of citrus waste for the synthesis of value added products. In Valorization of Citrus Food Waste, 179–213. (Springer, 2025).
Ibrahim, F. M. et al. Polyphenol-rich extracts and essential oil from Egyptian grapefruit peel as potential antioxidant, antimicrobial, and anti-inflammatory food additives. Appl. Sci. 14(7), 2776 (2024).
Zhang, M. et al. Ultrasound-assisted extraction of polysaccharides from Ginkgo biloba: Process optimization, composition and anti-inflammatory activity. Heliyon. 10(18) (2024).
Andrade, M. A. et al. Citrus by-products: Valuable source of bioactive compounds for food applications. Antioxidants 12(1), 38 (2022).
He, Y. et al. Effects of dietary fiber on human health. Food Sci. Hum. Wellness. 11(1), 1–10 (2022).
Timm, M. et al. Beyond insoluble dietary fiber: Bioactive compounds in plant foods. Nutrients 15(19), 4138 (2023).
Tufail, T. et al. Role of phytonutrients in the prevention and treatment of chronic diseases: A concrete review. ACS omega. 10(13), 12724–12755 (2025).
Qin, X. et al. Comparative analysis of dietary fibers from grapefruit peel prepared by ultrafine grinding: Structural properties, adsorption capacities, in vitro prebiotic activities. Food Bioscience. 56, 103163 (2023).
Wang, Z. et al. Effect of polysaccharide addition on food physical properties: A review. Food Chem. 431, 137099 (2024).
Liu, X. New Insights of Interactions between Cell Wall Polysaccharides and Procyanidins during Processing: Fate of Polysaccharides and Polyphenols during Processing (Université d’Avignon, 2021).
Roy, S. et al. Grapefruit seed extract-added functional films and coating for active packaging applications: A review. Molecules 28(2), 730 (2023).
Lesmana, D. et al. Valorization of peel-based agro-waste flour for food products: a systematic review on proximate composition and functional properties. ACS Food Sci. Technol. 2(1), 3–20 (2021).
Alahmari, L. A. Dietary fiber influence on overall health, with an emphasis on CVD, diabetes, obesity, colon cancer, and inflammation. Front. Nutr. 11, 1510564 (2024).
Kothari, D., Goswami, H. & Patel, N. Micronutrient and macronutrient-based bakery products: Perspectives and challenges. Biological Outlook to Improve the Nutritive Quality of Bakery Products 41–61 (2025).
Kutlu, G. et al. Incorporation of madımak (Polygonum cognatum Meissn.) leaf powder into gluten-free bread formulations: Evaluation of their nutritional, antidiabetic, color, bioactive, textural, and sensory properties. J. Sci. Food. Agric. 106(1), 493–502 (2026).
Castro-Vazquez, L. et al. Bioactive flavonoids, antioxidant behaviour, and cytoprotective effects of dried grapefruit peels (Citrus paradisi Macf). Oxidative Med. Cell. Longev. 2016(1), 8915729 (2016).
Baranwal, J. & Merino, D. Forefront strategies for biomass valorization: From deconstruction to bioplastic production. ACS Mater. Au. 5(4), 610–631 (2025).
Ye, Y. et al. Effects of ultrasonic modification on physicochemical and structural properties of pomelo peel soluble dietary fiber extracted by alkali. Sci. Rep. 15(1), 19224 (2025).
Gan, J. et al. Microwave assisted extraction with three modifications on structural and functional properties of soluble dietary fibers from grapefruit peel. Food Hydrocoll. 101, 105549 (2020).
Karaman, E., Yılmaz, E. & Tuncel, N. B. Physicochemical, microstructural and functional characterization of dietary fibers extracted from lemon, orange and grapefruit seeds press meals. Bioactive Carbohydr. Diet. Fibre. 11, 9–17 (2017).
Erol, K. F. et al. A sustainable innovation: Functionalization of pasta with methanol extract of Turkish red pine (Pinus brutia Ten.) barks. Waste Biomass Valoriz. 16(2), 805–816 (2025).
Düşkün, B. et al. Formulation of fiber-enriched crackers with oleaster powder: Effect on functional, textural, and sensory attributes. Plant Foods Hum. Nutr. 80(1), 82 (2025).
Islam, M. et al. Impact of different drying techniques on grapefruit peels and subsequent optimization of ultrasonic extraction conditions for bioactive compounds. J. Food Process Eng., 46(6), e14331. (2023).
Peng, G. et al. Combined microwave and enzymatic treatment improve the release of insoluble bound phenolic compounds from the grapefruit peel insoluble dietary fiber. Lwt 149, 111905 (2021).
Ahmed, S. et al. Chemical composition, antioxidant activity and GC-MS analysis of juice and peel oil of grapefruit varieties cultivated in India. J. Integr. Agric. 18(7), 1634–1642 (2019).
Bagdat, E. S., Kutlu, G. & Tornuk, F. The effect of free and encapsulated probiotic bacteria on some physicochemical, microbiological, and textural properties of apricot leather (pestil) during storage. J. Food Sci. 89(8), 4688–4703 (2024).
Mohamed, H. Extraction and characterization of pectin from grapefruit peels. MOJ Food Process. Technol. 2(1), 31–38 (2016).
Yalinkilic, B. & Cigdem, A. Effects of various citrus fiber coatings on the color, texture, and sensory properties of chicken nuggets. Int. J. Gastronomy Res. 3(1), 17–23 (2024).
Deng, M. et al. Physicochemical and functional properties of dietary fiber from pummelo (Citrus grandis L. Osbeck) and grapefruit (Citrus paradisi Mcfad) cultivars. Food Bioscience. 40, 100890 (2021).
Ahmad, M. M. et al. Variability in peel composition and quality evaluation of peel oils of citrus varieties. J. Agricultural Res. (JAR). 54(4), 747–756 (2016).
Ali, S. M. et al. Physicochemical, antioxidant and enzymes activities of grape fruit peel and pomace enriched functional drinks. Cell. Mol. Biol. 67(1), 125–131 (2021).
Cui, J. et al. The structure–property relationships of acid-and alkali-extracted grapefruit peel pectins. Carbohydr. Polym. 229, 115524 (2020).
Xie, J. et al. Physicochemical characteristics of soluble dietary fiber obtained from grapefruit peel insoluble dietary fiber and its effects on blueberry jam. Foods 11(22), 3735 (2022).
Davies, T. E. et al. Experimental methods in chemical engineering: Scanning electron microscopy and X-ray ultra‐microscopy—SEM and XuM. Can. J. Chem. Eng. 100(11), 3145–3159 (2022).
Demirkan, E. N. et al. Potential use of hazelnut (Corylus avellana L.) shell powder in muffin production by partial substitution of wheat flour: Color, bioactive, textural, and sensory properties. Eur. Food Sci. Eng. 5(1), 1–7 (2024).
Stabrauskiene, J. et al. Citrus× paradisi L. fruit waste: The impact of eco-friendly extraction techniques on the phytochemical and antioxidant potential. Nutrients 15(5), 1276 (2023).
Stabrauskiene, J. et al. Naringin and naringenin: Their mechanisms of action and the potential anticancer activities. Biomedicines 10(7), 1686 (2022).
Chen, Q. et al. Profiling of flavonoid and antioxidant activity of fruit tissues from 27 Chinese local citrus cultivars. Plants 9(2), 196 (2020).
Ukom, A. N., Ezenwigbo, M. C. & Ugwuona, F. U. Grapefruit peel powder as a functional ingredient in cake production: Effect on the physicochemical properties, antioxidant activity and sensory acceptability of cakes during storage. Int. J. Gastronomy Food Sci. 28, 100517 (2022).
Ali, H. & Naz, N. Free radical scavenging activity of pulps and peels of some selected vegetables commonly used in Pakistan. Pak. J. Agric. Res. 30(1) (2017).
Turkmen, F. U., Takci, H. A. M. & Sekeroglu, N. Total phenolic and flavonoid contents, antioxidant and antimicrobial activities of traditional unripe grape products. Indian J. Pharm. Educ. Res. 51(3s2), s489–s493 (2017).
Ayetigbo, O. et al. Review of instrumental texture measurements as phenotypic tool to assess textural diversity of root, tuber and banana food products. J. Sci. Food. Agric. 104(8), 4527–4539 (2024).
Wang, W. et al. Acoustic cavitation assisted extraction of pectin from waste grapefruit peels: A green two-stage approach and its general mechanism. Food Res. Int. 102, 101–110 (2017).
Ma, W. et al. Effect of modified grapefruit peel dietary fiber on bread: Baking quality, flavor characteristics, and starch digestive properties. Food Hydrocoll. 162, 110964 (2025).
Bouaziz, F. et al. Date seeds as a natural source of dietary fibers to improve texture and sensory properties of wheat bread. Foods 9(6), 737 (2020).
Yavuz, Z., Kutlu, G. & Tornuk, F. Incorporation of oleaster (Elaeagnus angustifolia L.) flour into white bread as a source of dietary fibers. J. Food Process. Preserv., 46(11), e17050. (2022).
Suri, S., Singh, A. & Nema, P. K. Current applications of citrus fruit processing waste: A scientific outlook. Appl. Food Res. 2(1), 100050 (2022).
Funding
The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.
Author information
Authors and Affiliations
Contributions
Farhan Saeed1, Habiba Arooj1, Bushra Niaz1, Amara Rasheed1, Faiyaz Ahmed2, Murodjon Yaxshimuratov3, Norbek Kholboyev4, Mariam Islam1, Hamna Zafar1, Muhammad Afzaal1, Fakhar Islam1,5, Catherine Tamale Ndagire-all the authors take part equally.
Corresponding authors
Ethics declarations
Ethical approval and consent to participate
This study did not directly involve human participants to check the therapeutic \effect of the product and was therefore exempt from ethical approval, as confirmed by the Office of Research, Innovation and Commercialization (ORIC) by following all the guidelines of National Biosafety Rules 2005, Punjab Biosafety Rules 2014, Punjab Animal Health Act 2019 and Bioethics Protocol Government College University, Faisalabad, Pakistan and in accordance with the Declaration of Helsinki. The sensory evaluation was conducted with trained PhD scholars. Informed consent was obtained from all participants prior to sensory evaluation.
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
Below is the link to the electronic supplementary material.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Saeed, F., Arooj, H., Niaz, B. et al. Extraction and characterization of grapefruit wall material (Citrus paradise) and its impact on organoleptic properties of bread. Sci Rep (2026). https://doi.org/10.1038/s41598-026-43129-z
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-43129-z
