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Teimouri Okhchlar R, Javadi A, Azadmard‐Damirchi S, Torbati M. Quality improvement of oil extracted from flaxseeds ( Linum usitatissimum L.) incorporated with olive leaves by cold press. Food Sci Nutr 2024; 12:3735-3744. [PMID: 38726418 PMCID: PMC11077233 DOI: 10.1002/fsn3.4044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 01/30/2024] [Accepted: 02/08/2024] [Indexed: 05/12/2024] Open
Abstract
Flaxseed oil has a high amount of α-linolenic acid (an ω3 essential fatty acid), but it is very prone to oxidation. Therefore, olive leaves were used as a rich source of phenolic compounds with flaxseeds upon oil extraction by cold press to enhance the oxidative stability of extracted oils. Oil from flaxseeds with unblanched leaves and blanched leaves at level of (0 [control sample], 2.5, 5, 7.5, and 10% w/w) was extracted by cold press. Quality of extracted oils was evaluated for 90 days of storage at room condition. Incorporation of unblanched olive leaves could increase the acid value of the extracted oils up to 2.0 (mg KOH/g oil) compared to the other samples. Oxidation of the flaxseed oil could be delayed by the addition of blanched olive leaves up to 5%. Oil extracted from flaxseeds incorporated with blanched olive leaves had higher content of carotenoids (up to 33.7 mg/kg oil), chlorophylls (up to 35.7 mg/kg oil), and phenolic compounds (up to 200 mg/kg oil). Also, oxidative stability of extracted oils was higher up to 7.5% of blanched olive leaves (11.4 h) compared to control sample (7.2 h) and other oil samples. Polyunsaturated fatty acids of the oil samples were well preserved by the incorporation of blanched olive leaves. Based on the obtained results, incorporation of suitable amount of blanched olive leaves (up to 7.5%) with flaxseeds before oil extraction by press can be an appropriate procedure to produce oils with high content of bioactive components and suitable oxidative stability.
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Affiliation(s)
- Ramin Teimouri Okhchlar
- Department of Food Science and Technology, Mamaghan BranchIslamic Azad UniversityMamaghanIran
| | - Afshin Javadi
- Department of Food Science and Technology, Mamaghan BranchIslamic Azad UniversityMamaghanIran
- Department of Food Hygiene, Faculty of Veterinary, Tabriz Medical ScienceIslamic Azad UniversityTabrizIran
| | | | - Mohammadali Torbati
- Department of Food Science and Technology, Faculty of Nutrition and Food ScienceTabriz University of Medical SciencesTabrizIran
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Ronca CL, Marques SS, Ritieni A, Giménez-Martínez R, Barreiros L, Segundo MA. Olive Oil Waste as a Source of Functional Food Ingredients: Assessing Polyphenolic Content and Antioxidant Activity in Olive Leaves. Foods 2024; 13:189. [PMID: 38254490 PMCID: PMC10814828 DOI: 10.3390/foods13020189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 12/31/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Around two million tons of olive oil are produced in Europe annually, with Portugal being among the top five European olive oil-producing countries. Olive oil production results in a substantial amount of waste in the form of olive leaves. These discarded olive leaves contain valuable phenolic compounds with antioxidant, anti-inflammatory, hypoglycaemic, neuroprotective, and antiproliferative properties. Due to their richness in polyphenols with health-promoting properties, olive leaves can be considered a potential functional food ingredient. Thus, sustainable practices for reusing olive leaf waste are in demand. In this study, the polyphenolic content in olive leaves from different Portuguese locations was determined using HPLC-UV-Vis after defining the best fit-for-purpose liquid extraction strategy. The differences in the in vitro antioxidant activity in these samples were determined by several methodologies based on radical scavenging (against 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-2-picrylhydrazyl (DPPH), and peroxyl radical (ORAC)) and on reducing properties (cupric-reducing antioxidant capacity (CUPRAC), and Folin-Ciocalteu assay (FC)), to unveil the relationship between the profile and quantity of polyphenols with antioxidant mechanisms and their capacity. At last, the stability of extracted compounds upon lyophilization and exposition to surrogate biological fluids was assessed, envisioning the future incorporation of olive leaves extracted compounds in food products.
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Affiliation(s)
- Carolina L. Ronca
- LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4099-002 Porto, Portugal; (C.L.R.); (S.S.M.); (L.B.)
- Department of Pharmacy, Faculty of Pharmacy, University of Naples “Federico II”, 80138 Naples, Italy
- Department of Nutrition and Bromatology, School of Pharmacy, University of Granada, 18012 Granada, Spain;
| | - Sara S. Marques
- LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4099-002 Porto, Portugal; (C.L.R.); (S.S.M.); (L.B.)
| | - Alberto Ritieni
- Department of Pharmacy, Faculty of Pharmacy, University of Naples “Federico II”, 80138 Naples, Italy
| | - Rafael Giménez-Martínez
- Department of Nutrition and Bromatology, School of Pharmacy, University of Granada, 18012 Granada, Spain;
| | - Luisa Barreiros
- LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4099-002 Porto, Portugal; (C.L.R.); (S.S.M.); (L.B.)
- School of Health, Polytechnic Institute of Porto, 4200-072 Porto, Portugal
| | - Marcela A. Segundo
- LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4099-002 Porto, Portugal; (C.L.R.); (S.S.M.); (L.B.)
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