Olive Leaf, Thyme and Green Walnut Husk Extracts as Functional Ingredients in Dairy Products: A Review.
- 1Karlovac University of Applied Sciences, Trg J. J. Strossmayera 9, 47000 Karlovac, Croatia.
- 2Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, Franje Kuhača 18, 31000 Osijek, Croatia.
- 3Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
Abstract
Oxidative stress and the associated inflammation play key roles in the development of many chronic diseases. As alternatives to synthetic antioxidants, plant-derived materials with potential anti-inflammatory and antioxidant properties, such as olive (Olea europaea) leaves, thyme (Thymus vulgaris) and green walnut (Juglans regia) husks, have attracted increasing scientific interest. These materials are rich in phenolic compounds, including oleuropein and hydroxytyrosol in olive leaves, thymol and rosmarinic acid in thyme, and ellagitannins and juglone in green walnut husks. Numerous studies have demonstrated the strong antioxidant activity of these extracts using analytical assays such as DPPH, FRAP and ABTS. However, such in vitro antioxidant capacity does not necessarily translate directly into biological efficacy in vivo, as polyphenol stability, release, metabolism and bioavailability may be strongly influenced by interactions with proteins, lipids and other components of dairy matrices. Their incorporation into dairy products has shown promising technological effects, including improved oxidative stability, reduced lipid oxidation, delayed microbial spoilage and potential shelf-life extension. Reported application contents vary substantially among studies and product types, including 0.4-5 % for olive leaf extract in yogurt systems, 0.4-0.8 % for thyme extract in yogurt, 0.1-1 mg/mL for thyme extract in milk systems, 0.5-3 % for olive leaf extract in cheeses, and 100-200 mg/kg for green walnut husk extract in cream-based products. However, these values should be interpreted cautiously because extract composition, matrix type and units of expression differ among studies. Nevertheless, evidence supporting direct health benefits in humans remains limited, and further in vivo and human intervention studies are needed to confirm their physiological relevance. This review summarises the polyphenolic profiles of the olive leaf, thyme and green walnut husk extracts, their technological and sensory effects in dairy matrices, and advances in sustainable extraction methods. Overall, the available findings support their potential as natural, clean-label ingredients for innovative dairy products, primarily from a technological and functional formulation perspective.
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BibTeX
@article{zandona2026olive,
title = {{Olive Leaf, Thyme and Green Walnut Husk Extracts as Functional Ingredients in Dairy Products: A Review.}},
author = {Elizabeta Zandona and Vedrana Pleš and Silvija Pavković and Ines Cindrić and Almir Abdurramani and Vesna Zechner-Krpan and Irena Barukčić Jurina and Marijana Blažić},
journal = {Food technology and biotechnology},
year = {2026},
month = jul,
doi = {10.17113/ftb.64.03.26.9519},
url = {https://europepmc.org/article/MED/42910356},
note = {CC BY},
}
RIS
TY - JOUR
TI - Olive Leaf, Thyme and Green Walnut Husk Extracts as Functional Ingredients in Dairy Products: A Review.
AU - Elizabeta Zandona
AU - Vedrana Pleš
AU - Silvija Pavković
AU - Ines Cindrić
AU - Almir Abdurramani
AU - Vesna Zechner-Krpan
AU - Irena Barukčić Jurina
AU - Marijana Blažić
PY - 2026
DA - 2026/07/01
JO - Food technology and biotechnology
DO - 10.17113/ftb.64.03.26.9519
UR - https://europepmc.org/article/MED/42910356
AB - Oxidative stress and the associated inflammation play key roles in the development of many chronic diseases. As alternatives to synthetic antioxidants, plant-derived materials with potential anti-inflammatory and antioxidant properties, such as olive (Olea europaea) leaves, thyme (Thymus vulgaris) and green walnut (Juglans regia) husks, have attracted increasing scientific interest. These materials are rich in phenolic compounds, including oleuropein and hydroxytyrosol in olive leaves, thymol and rosmarinic acid in thyme, and ellagitannins and juglone in green walnut husks. Numerous studies have demonstrated the strong antioxidant activity of these extracts using analytical assays such as DPPH, FRAP and ABTS. However, such in vitro antioxidant capacity does not necessarily translate directly into biological efficacy in vivo, as polyphenol stability, release, metabolism and bioavailability may be strongly influenced by interactions with proteins, lipids and other components of dairy matrices. Their incorporation into dairy products has shown promising technological effects, including improved oxidative stability, reduced lipid oxidation, delayed microbial spoilage and potential shelf-life extension. Reported application contents vary substantially among studies and product types, including 0.4-5 % for olive leaf extract in yogurt systems, 0.4-0.8 % for thyme extract in yogurt, 0.1-1 mg/mL for thyme extract in milk systems, 0.5-3 % for olive leaf extract in cheeses, and 100-200 mg/kg for green walnut husk extract in cream-based products. However, these values should be interpreted cautiously because extract composition, matrix type and units of expression differ among studies. Nevertheless, evidence supporting direct health benefits in humans remains limited, and further in vivo and human intervention studies are needed to confirm their physiological relevance. This review summarises the polyphenolic profiles of the olive leaf, thyme and green walnut husk extracts, their technological and sensory effects in dairy matrices, and advances in sustainable extraction methods. Overall, the available findings support their potential as natural, clean-label ingredients for innovative dairy products, primarily from a technological and functional formulation perspective.
SN - 1330-9862
SN - 1334-2606
ER -