Identification and quantification of phenolic compounds in kernels, oil and bagasse pellets of common walnut (Juglans regia L.)

Slatnar, Ana; Mikulič-Petkovšek, Maja; Štampar, Franci; Veberič, Robert; Solar, A.

doi:10.1016/j.foodres.2014.11.016

Cited by 126 publications

(89 citation statements)

References 34 publications

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“…On the other hand, our values were found to be lower than those reported for Slovenia (Czaplicki et al, ) (50 mg kg). The composition of polyphenols in walnut oil was not prominent, Slatnar, Mikulic‐Petkovsek, Stampar, Veberic, and Solar () quantified the phenolic compounds in kernels and oil of common walnut ( J. regia L.), and identified six individual phenolic compounds with Glansreginin B and Glansreginin A being the major components.…”

Section: Resultsmentioning

confidence: 99%

Chemical Compositions of Walnut (Juglans regia L.) Oils from Different Cultivated Regions in China

Gao

Jin

Liu

et al. 2018

J Americ Oil Chem Soc

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This study is a comprehensive report on the quality of Chinese walnut oil, which enriches the research of oil resources. A total of 16 walnut samples from China were selected, and walnut oils were obtained using the pressing process. The lipid compositions and micronutrient contents were analyzed. The fatty acids corresponded to palmitic acid (3.05–8.25%), oleic acid (12.56–26.03%), linoleic acid (51.21–68.97%), and linolenic acid (6.83–15.01%), and the main triacylglycerols were trilinolein (27.87–39.47%), followed by oleoyl‐linoleoyl‐linolenoyl‐glycerol (17.07–24.18%), dilinoleoyl‐oleoyl‐glycerol (9.65–15.46%), palmitoyl‐dilinoleoyl‐glycerol (5.96–14.98%), and dilinoleoyl‐linolenoyl‐glycerol (6.42–12.43%). In addition, high amounts of micronutrients, including phytosterol, squalene, tocopherol, and total phenolic content, were found in walnut oils ranging from 540 to 1594, 17 to 131, 345 to 1280, and 1.04 to 20.39 mg kg−1 among different samples, respectively. The differences in the geographical location and climate caused different regions of cultivation, which resulted in the differences in the chemical composition of walnut oil. Further multiple linear regression analyses between oxidative stability indices, fatty‐acid compositions, and micronutrients revealed that linoleic acid (R = −0.891; P < 0.05), α‐tocopherol (R = 0.713; P < 0.05), and total phenolic content (R = 0.369; P < 0.05) were the main factors that affect the oxidative stability of the walnut oil.

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Section: Resultsmentioning

confidence: 99%

Chemical Compositions of Walnut (Juglans regia L.) Oils from Different Cultivated Regions in China

Gao

Jin

Liu

et al. 2018

J Americ Oil Chem Soc

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“…As a result, only minor amounts of walnut phenolics could be present in the extracted oils. [ 126,127 ]…”

Section: Chemistry and Quality Of Nut Oilsmentioning

confidence: 99%

Tree Nut Oils: Chemical Profiles, Extraction, Stability, and Quality Concerns

Maestri

Cittadini

Bodoira

et al. 2020

Euro J Lipid Sci & Tech

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Tree nuts are globally consumed. Their kernels are calorie-rich, nutrient-dense foods and contain several bioactive and health-promoting components. While some nut crops have expanded through the world since ancient times (almond, hazelnut, walnut), more recently, there has been a parallel development of underexploited promising species (Brazil nut, macadamia, pecan). Nut kernels have high lipid content, ranging from 40% to 80% depending on nut species and varieties. In general, nut oils contain significant proportions of nutritionally and medicinally desirable fatty acids and nutraceutical compounds (sterols, tocopherols, and other phenolics). A considerable genetic variability in oil content and composition is present in nut genetic resources worldwide. This suggests the possibility of different breeding lines focused to enhance oil yields, chemical and quality traits. Regarding extraction, screw-pressing is suitable to achieve high oil recovery and good quality standards, but seed materials should be conditioned appropriately. Seed moisture content and pressing temperature appear as key variables to enhance oil recovery. This article presents an overview on chemical profiles, mechanical extraction, and quality concerns of oils from the most widely produced tree nut crops. The revision is also aimed at identifying areas where knowledge is insufficient and to set priorities for further research. Practical applications: The review updates and increases knowledge about oils from tree nut genetic resources, encompassing genetic variability and environmental effects on oil yield and compositional traits. It also analyzes findings regarding oil extraction and provides useful insights to establish better conditions for achieving sustainable oil yields and good quality standards.

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“…Walnut kernels typically contain 52% to 72% oil, depending on the cultivar, geographical location, and irrigation rate (Martínez et al, ; Slatnar et al, ). This oil is extracted on a small scale for use in food as a flavoring agent, mainly as a salad dressing and in bakery products.…”

Section: Introductionmentioning

confidence: 99%

“…Like most nuts, walnuts are valuable sources of polyunsaturated fatty acids (PUFA; 90% of the oil), predominantly linoleic (47.4%) and α‐linolenic acids (15.8%) (Slatnar et al, ). Because of its composition, walnut oil consumption reduces serum cholesterol levels in humans, by lowering the low‐density lipoprotein, increasing the high‐density lipoprotein and decreasing the total triacylglycerol levels (Liang et al, ).…”

Section: Introductionmentioning

confidence: 99%

Antioxidant Activity Displayed by Phenolic Compounds Obtained from Walnut Oil Cake used for Walnut Oil Preservation

Grosso

Asensio

Nepote

et al. 2018

J Americ Oil Chem Soc

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The objective of this work was to evaluate the performance of various antioxidants (ethyl acetate-soluble polyphenols: PAE; water-soluble polyphenols: PH; and butylated hydroxytoluene [BHT]) on the preservation of walnut oil (W) during storage. An oven test was conducted on the walnut oil samples: without antioxidants (control: WC) and with antioxidants: PAE (WPAE), PH (WPH), and BHT (WBHT) during a 16-day storage at 60 C temperature. Chemical parameters related to deterioration were analyzed during storage: peroxide value (PV), conjugated dienes (CD) and conjugated trienes (CT), and carotenoid content (CC). Volatile compounds were also analyzed. PV, CD, CT, and volatile compounds related to oxidation of lipids such as; nonanal, hexanal, butanal, and (E)-2-heptenal increased in all samples during storage. The increase of these variables was greater in WC and lower in WPAE and WPH. WPAE, WPH, and WBHT displayed a better preservation of volatile compounds that influence the walnut-characteristic flavor like D-limonene, and a lower increase of aldehydes and furans. The CC exhibited a decrease in all samples during storage. WPAE presented the greatest CC value along the storage and was followed by WPH. Antioxidants helped to preserve walnut oil against deterioration processes. PAE and PH displayed good antioxidant activity and in some cases showed a better performance for quality preservation of walnut oil compared to the BHT antioxidant.

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Identification and quantification of phenolic compounds in kernels, oil and bagasse pellets of common walnut (Juglans regia L.)

Cited by 126 publications

References 34 publications

Chemical Compositions of Walnut (Juglans regia L.) Oils from Different Cultivated Regions in China

Chemical Compositions of Walnut (Juglans regia L.) Oils from Different Cultivated Regions in China

Tree Nut Oils: Chemical Profiles, Extraction, Stability, and Quality Concerns

Antioxidant Activity Displayed by Phenolic Compounds Obtained from Walnut Oil Cake used for Walnut Oil Preservation

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