Important progress has been made in the study of phenolic substance form and antioxidant activity in walnut kernels

　　Walnut (Juglans regiaL.
) is one of the four largest foodmate.
net/tag_887.
html" class="zdbq" title="Nuts related food information" target="_blank">nuts in the world.
It has significant health effects in lowering blood sugar, lowering blood lipids, and preventing cardiovascular diseases.
Studies have shown that the health function of walnut is mainly related to its foodmate.
net/tag_1006.
html" class="zdbq" title="Antioxidant related food information" target="_blank">antioxidant capacity, which in turn is related to the rich foodmate.
net/tag_411.
html" class="zdbq" title="Polyphenol-related food information" target="_blank">polyphenols in walnut kernels .
Polyphenols can be divided into soluble free phenols, soluble esterified phenols and insoluble bound phenols according to the way they are combined with the food matrix.
However, the current research on nut polyphenols is mainly focused on free polyphenols, which greatly limits the in-depth study of their physiological activities and the development of corresponding functionally active products.

 

　　foodmate.
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html" class="zdbq" title="China-related food information" target="_blank">Chinese Academy Yalin eaten forest foodmate.
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html" class="zdbq" title="Quality and safety related food information" target="_blank">mass safety youth team via innovative high foodmate.
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html" class="zdbq" title="Liquid phase related food information" target="_blank">liquid to achieve 37 phenolic component at less walnuts (nuts) in three forms tandem triple quadrupole mass spectrometer (HPLC-MS / MS) chromatogram The qualitative and quantitative results found that it is different from the previous reports in which foodmate.
net/tag_1740.
html" class="zdbq" title="Fruit related food information" target="_blank">fruit and foodmate.
net/tag_601.
html" class="zdbq" title="Cereal-related food information" target="_blank">grains are dominated by bound phenols.
This result suggests for the first time that walnut polyphenols mainly exist in free form, and that jugquinone, kaempferol, and quercetin-7-o -β-D- foodmate.
net/tag_1417.
html" class="zdbq" title="Glucose related food information" target="_blank">glucose glycosides and dihydroquercetin are present only in the free phenol; reported previously proposed in free phenol content and antioxidative capacity linear correlation on the basis of positive, confirming the esterification and bound phenols are also similar Phenomenon; From the perspective of extraction efficiency, acetone has been proven to have a higher ability to extract soluble phenolic substances (free and esterified), especially for hydroxycinnamic acids and flavanols; while methanol is better at extracting insoluble substances Bound phenolic substances.
This result will deepen the understanding of the basic theory of walnut characteristic metabolites and the distribution of phenols, and provide a theoretical basis for promoting the efficient development of walnut phenols and the design of functional foods.

 

　　This research was funded by the basic scientific research of the Chinese Academy of Forestry.
The related results were published in the international academic Top Journal "Food Chemistry" ("Food Chemistry").
The online publication title is "Phenolic profiles and antioxidant activities of free, esterified and bound phenolic compounds in walnut kernel".
Master student Wu Shutian and experimenter Shen Danyu are the co-first authors of the paper, and associate researcher Liu Yihua is the corresponding author.
(Liu Yihua/Yalin Institute)

 

　　Link to the paper: https://doi.
org/10.
1016/j.
foodchem.
2021.
129217