{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T18:58:36Z","timestamp":1785437916971,"version":"3.56.0"},"reference-count":39,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T00:00:00Z","timestamp":1775174400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100016047","name":"Science Fund of the Republic of Serbia","doi-asserted-by":"publisher","award":["7439"],"award-info":[{"award-number":["7439"]}],"id":[{"id":"10.13039\/501100016047","id-type":"DOI","asserted-by":"publisher"}]},{"award":["7439"],"award-info":[{"award-number":["7439"]}],"id":[{"id":"https:\/\/ror.org\/02r531a15","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Ministry of Science, Technological Development and Innovation of the Republic of Serbia","award":["451-03-33\/2026-03\/200023"],"award-info":[{"award-number":["451-03-33\/2026-03\/200023"]}]},{"name":"Ministry of Science, Technological Development and Innovation of the Republic of Serbia","award":["451-03-33\/2026-03\/200051"],"award-info":[{"award-number":["451-03-33\/2026-03\/200051"]}]},{"name":"Ministry of Science, Technological Development and Innovation of the Republic of Serbia","award":["451-03-33\/2026-03\/200168"],"award-info":[{"award-number":["451-03-33\/2026-03\/200168"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Foods"],"abstract":"<jats:p>Zinc deficiency is recognized as a global public health concern, affecting populations of all ages. This study aims to develop zinc supplements (nutraceuticals) based on by-products of the fruit and vegetable processing industry. Dehydrated apple and beetroot pomace powders were enriched with vitamin C and zinc via fluid-bed wet granulation, producing granules with substantially improved flowability (Carr\u2019s index reduced by up to 45%, Hausner ratio by up to 25%, while the bulk and tapped density were reduced by up to 25% and 40%, respectively). Microbiological and long-term storage stability was demonstrated by low water activity (aw) (\u22640.3), moisture content (&lt;10%), and glass transition temperatures (Tg = 29\u201334 \u00b0C) that were well above standard storage conditions. The formulated nutraceuticals exhibited stronger antioxidant activity compared to the starting powders, as well as significant anti-hyperglycemic activity. Furthermore, the enhanced bioaccessibility of zinc was confirmed upon in vitro digestion of granulated samples, using atomic absorption spectrometry and differential pulse voltammetry. The present findings demonstrate that apple and beetroot pomaces can be successfully valorized as sustainable and functional matrices for zinc enrichment, being free of gluten, artificial sweeteners, colorants, preservatives, anti-caking agents, and anti-nutritional factors such as phytic acid.<\/jats:p>","DOI":"10.3390\/foods15071219","type":"journal-article","created":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T00:19:32Z","timestamp":1775434772000},"page":"1219","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Valorization of Fruit and Vegetable Pomace: Development of Zinc-Enriched Nutraceutical"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0359-4399","authenticated-orcid":false,"given":"Tatjana","family":"\u0160o\u0161tari\u0107","sequence":"first","affiliation":[{"name":"Institute for Technology of Nuclear and Other Mineral Raw Materials, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7251-8699","authenticated-orcid":false,"given":"Zorica","family":"Lopi\u010di\u0107","sequence":"additional","affiliation":[{"name":"Institute for Technology of Nuclear and Other Mineral Raw Materials, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8450-602X","authenticated-orcid":false,"given":"Sne\u017eana","family":"Zlatanovi\u0107","sequence":"additional","affiliation":[{"name":"Institute of General and Physical Chemistry, Studentski Trg 12\/V, 11158 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ferenc T.","family":"Pastor","sequence":"additional","affiliation":[{"name":"University of Belgrade, Faculty of Chemistry, Studentski Trg 12, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1585-7707","authenticated-orcid":false,"given":"Mihal","family":"Djuris","sequence":"additional","affiliation":[{"name":"University of Belgrade, Institute of Chemistry, Technology and Metallurgy\u2014National Institute of the Republic of Serbia, Njego\u0161eva 12, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3676-5892","authenticated-orcid":false,"given":"Stanislava","family":"Gorjanovi\u0107","sequence":"additional","affiliation":[{"name":"Institute of General and Physical Chemistry, Studentski Trg 12\/V, 11158 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2791","DOI":"10.1038\/s41598-024-53202-0","article-title":"Demographic and clinical characteristics of patients with zinc deficiency: Analysis of a nationwide Japanese medical claims database","volume":"14","author":"Yokokawa","year":"2024","journal-title":"Sci. Rep."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Preedy, V., and Patel, V. (2018). Zinc Deficiency and Stunting. Handbook of Famine, Starvation, and Nutrient Deprivation, Springer.","DOI":"10.1007\/978-3-319-40007-5"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.nutos.2022.06.006","article-title":"The effect of Vitamin C and Zn supplementation on the immune system and clinical outcomes in COVID-19 patients","volume":"44","author":"Firouzi","year":"2022","journal-title":"Clin. Nutr. Open Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"178","DOI":"10.1007\/s12020-013-0032-x","article-title":"Zinc and insulin in pancreatic beta-cells","volume":"45","author":"Li","year":"2014","journal-title":"Endocrine"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.clnesp.2022.08.003","article-title":"Effects of zinc supplementation on glycemic control and oxidative stress in experimental diabetes: A systematic review","volume":"51","author":"Martins","year":"2022","journal-title":"Clin. Nutr. ESPEN"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Ahmad, R., Shaju, R., Atfi, A., and Razzaque, M.S. (2024). Zinc and Diabetes: A Connection between Micronutrient and Metabolism. Cells, 15.","DOI":"10.3390\/cells13161359"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"\u0160o\u0161tari\u0107, T., Simi\u0107, M., Lopi\u010di\u0107, Z., Zlatanovi\u0107, S., Pastor, F., Antanaskovi\u0107, A., and Gorjanovi\u0107, S. (2023). Food Waste (Beetroot and Apple Pomace) as Sorbent for Lead from Aqueous Solutions\u2014Alternative to Landfill Disposal. Processes, 11.","DOI":"10.3390\/pr11051343"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Gorjanovi\u0107, S., Mici\u0107, D., Pastor, F., Tosti, T., Kalu\u0161evi\u0107, A., Risti\u0107, S., and Zlatanovi\u0107, S. (2020). Evaluation of Apple Pomace Flour Obtained Industrially by Dehydration as a Source of Biomolecules with Antioxidant, Antidiabetic and Antiobesity Effects. Antioxidants, 9.","DOI":"10.3390\/antiox9050413"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Mitrevski, J., Panteli\u0107, N.\u0110., Lali\u010di\u0107-Petronijevi\u0107, J., Koji\u0107, J.S., Zlatanovi\u0107, S., Gorjanovi\u0107, S., Avramov, S., Dodevska, M.S., and Anti\u0107, V.V. (2025). Low Glycemic Index Biscuits Enriched with Beetroot Powder as a Source of Betaine and Mineral Nutrients. Foods, 14.","DOI":"10.3390\/foods14050814"},{"key":"ref_10","unstructured":"Zlatanovi\u0107, S., Gorjanovi\u0107, S., Mici\u0107, D., Pastor, F., Tosti, T., Kalu\u0161evi\u0107, A., and Risti\u0107, S. (2020). Method for Producing Gluten-Free Flour Made of Apple Pomace. (WO Patent 2020\/027683A1)."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Jovanovic, M., Zlatanovic, S., Micic, D., Bacic, D., Mitic-Culafic, D., \u00d0uri\u0161, M., and Gorjanovic, S. (2021). Functionality and Palatability of Yogurt Produced Using Beetroot Pomace Flour Granulated with Lactic Acid Bacteria. Foods, 10.","DOI":"10.3390\/foods10081696"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"105146","DOI":"10.1016\/j.fbio.2024.105146","article-title":"New insight in the progress of zinc polysaccharide complex: Preparation, structural features, bioactivities and application","volume":"62","author":"Zhang","year":"2024","journal-title":"Food Biosci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"118482","DOI":"10.1016\/j.ijpharm.2019.118482","article-title":"Microstructural Characterization of Carrier-Based Dry Powder Inhalation Excipients: Insights and Guidance","volume":"568","author":"Elsayed","year":"2019","journal-title":"Int. J. Pharm."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.powtec.2016.08.045","article-title":"Optimal pixel resolution for sand particles size and shape analysis","volume":"302","year":"2016","journal-title":"Powder Technol."},{"key":"ref_15","unstructured":"(2013). Standard Test Method for Moisture Analysis of Particulate Wood Fuels (Standard No. ASTM E871-82(2013))."},{"key":"ref_16","unstructured":"(2015). Standard Test Method for Ash in Biomass (Standard No. ASTM E1755-01(2015))."},{"key":"ref_17","unstructured":"(2019). Standard Test Method for Volatile Matter in the Analysis of Particulate Wood Fuels (Standard No. ASTM E872-82(2019))."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"991","DOI":"10.1038\/s41596-018-0119-1","article-title":"INFOGEST Static In Vitro Simulation of Gastrointestinal Food Digestion","volume":"14","author":"Brodkorb","year":"2019","journal-title":"Nat. Protoc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"144","DOI":"10.5344\/ajev.1965.16.3.144","article-title":"Colorimetry of Total Phenolics with Phosphomolybdic\u2013Phosphotungstic Acid Reagents","volume":"16","author":"Singleton","year":"1965","journal-title":"Am. J. Enol. Vitic."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1199","DOI":"10.1038\/1811199a0","article-title":"Antioxidant Determinations by the Use of a Stable Free Radical","volume":"181","author":"Blois","year":"1958","journal-title":"Nature"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1006\/abio.1996.0292","article-title":"The Ferric Reducing Ability of Plasma (FRAP) as a Measure of \u201cAntioxidant Power\u201d: The FRAP Assay","volume":"239","author":"Benzie","year":"1996","journal-title":"Anal. Biochem."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Zlatanovi\u0107, S., Lali\u010di\u0107-Petronijevi\u0107, J., Pastor, F., Mici\u0107, D., Dodevska, M., Stevanovi\u0107, M., Karlovi\u0107, S., and Gorjanovi\u0107, S. (2025). Agro-Residues and Sucrose Alternatives in Confectionery Transformation Towards Glucose Spikes Minimization. Foods, 14.","DOI":"10.3390\/foods14030491"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"58","DOI":"10.2174\/1386207318666151102094227","article-title":"Antioxidant Capacity Determination of Complex Samples and Individual Phenolics\u2014Multilateral Approach","volume":"19","author":"Pastor","year":"2016","journal-title":"Comb. Chem. High Throughput Screen."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2393","DOI":"10.1002\/jsfa.6564","article-title":"Anthocyanin Profiles and Biological Properties of Caneberry (Rubus spp.) Press Residues","volume":"94","author":"Djilas","year":"2014","journal-title":"J. Sci. Food Agric."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1208\/s12249-013-0036-0","article-title":"The Effect of Moisture on the Flowability of Pharmaceutical Excipients","volume":"15","author":"Crouter","year":"2014","journal-title":"AAPS PharmSciTech"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1016\/j.jfoodeng.2005.09.025","article-title":"Evaluating Water Activity and Glass Transition Concepts for Food Stability","volume":"78","author":"Sablani","year":"2007","journal-title":"J. Food Eng."},{"key":"ref_27","unstructured":"Roos, Y.H. (2016). Phase Transitions in Foods, Academic Press. [2nd ed.]."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.tca.2019.01.009","article-title":"Thermal Behaviour and Degradation Kinetics of Apple Pomace Flours","volume":"673","author":"Rankov","year":"2019","journal-title":"Thermochim. Acta"},{"key":"ref_29","unstructured":"National Center for Biotechnology Information (2026, March 19). PubChem Compound Summary for CID 91667835, Zinc Ascorbate, Available online: https:\/\/pubchem.ncbi.nlm.nih.gov\/compound\/Zinc-ascorbate."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Hecel, A., Ostrowska, M., Stokowa-So\u0142tys, K., W\u0105t\u0142y, J., Dudek, D., Miller, A., Potocki, S., Matera-Witkiewicz, A., Dominguez-Martin, A., and Koz\u0142owski, H. (2020). Zinc(II)\u2014The Overlooked \u00c9minence Grise of Chloroquine\u2019s Fight against COVID-19?. Pharmaceuticals, 13.","DOI":"10.3390\/ph13090228"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Hall, A.G., and King, J.C. (2023). The Molecular Basis for Zinc Bioavailability. Int. J. Mol. Sci., 24.","DOI":"10.3390\/ijms24076561"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Tokarczyk, J., and Koch, W. (2025). Dietary Zn\u2014Recent Advances in Studies on Its Bioaccessibility and Bioavailability. Molecules, 30.","DOI":"10.3390\/molecules30132742"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Rock, N., Clynes, M., Horgan, K., Murphy, R., O\u2019Sullivan, F., and Keenan, J. (2026). The Antagonistic Influence of Phytic Acid on Zinc Absorption: An In Vitro Comparison of Inorganic and Chelated Trace Mineral Sources. Nutrients, 18.","DOI":"10.3390\/nu18010046"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Inoue, Y., Cormanes, L., Yoshimura, K., Sano, A., Hori, Y., Suzuki, R., and Kanamoto, I. (2022). Effect of Apple Consumption on Postprandial Blood Glucose Levels in Normal Glucose Tolerance People versus Those with Impaired Glucose Tolerance. Foods, 11.","DOI":"10.3390\/foods11121803"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"104216","DOI":"10.1016\/j.tifs.2023.104216","article-title":"Beetroot for Managing Diabetes and Its Associated Gut Dysbiosis: Current Findings and Challenges","volume":"142","author":"Daliri","year":"2023","journal-title":"Trends Food Sci. Technol."},{"key":"ref_36","unstructured":"Dubois, S. (2014). The Ability of Berry Extracts to Inhibit Alpha-Glucosidase In Vitro. [Honors Thesis, University of Maine]. Available online: https:\/\/digitalcommons.library.umaine.edu\/honors\/168."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1759","DOI":"10.1016\/j.foodchem.2011.11.134","article-title":"Antioxidant Capacity and \u03b1-Glucosidase Inhibitory Activity in Peel and Flesh of Blueberry (Vaccinium spp.) Cultivars","volume":"132","author":"Wang","year":"2012","journal-title":"Food Chem."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Neagu, E., Paun, G., Albu, C., and Radu, G.L. (2024). Valorization of Bioactive Compounds from Lingonberry Pomace and Grape Pomace with Antidiabetic Potential. Molecules, 29.","DOI":"10.3390\/molecules29225443"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"104500","DOI":"10.1016\/j.jff.2021.104500","article-title":"Effects of Dietary Fiber on Glycemic Control and Insulin Sensitivity in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis","volume":"82","author":"Mao","year":"2021","journal-title":"J. Funct. Foods"}],"container-title":["Foods"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2304-8158\/15\/7\/1219\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T00:43:00Z","timestamp":1775436180000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2304-8158\/15\/7\/1219"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,3]]},"references-count":39,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["foods15071219"],"URL":"https:\/\/doi.org\/10.3390\/foods15071219","relation":{},"ISSN":["2304-8158"],"issn-type":[{"value":"2304-8158","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,3]]}}}