Oxidative Stability of Walnut Kernel and Oil: Chemical Compositions and Sensory Aroma Compounds

Ampofo, Josephine; Grilo, Filipa; Langstaff, Sue; Wang, Selina C.

doi:10.3390/foods11193151

Cited by 8 publications

(4 citation statements)

References 42 publications

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“…Peroxides in their turn will undergo changes thus forming compounds such as aldehydes, ketones, etc., the presence of which degrades the quality of the final product (Abeyrathne et al, 2021;Subotin et al, 2021). According to Ampofo and Grilo (2022), the peroxide value of walnut oil reaches 1.80 meq O 2 /kg after 4 months of storage, while FFA ranges within 0.02 -0.03 Oleic acid g/100g (Ampofo et al, 2022). The difference in FFA content of our walnut paste and the values reported in the previously mentioned study can be linked to the low moisture contents of kernels, thus the lipase activity for FFA formation is limited.…”

Section: Oxidative Stabilitymentioning

confidence: 99%

Walnut Paste: A Healthy Alternative for Nutella Consumers

Covaliov¹,

Siminiuc²,

POPOVICI³

2023

EPHELS

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Nutella is the best-selling chocolate and hazelnut spread in the world. It is known that the main ingredients of Nutella are sugar (55%) palm oil (23%), hazelnuts (14%), cocoa solids and skimmed milk (8%). Currently, worldwide, there is a tendency to make healthier food choices, and the sugar and palm oil from Nutella’s formulation are ingredients blamed for causing certain health disorders (obesity, cardiovascular diseases and diabetes). In this order, the purpose of the research was to develop the technology for obtaining walnut paste, since walnuts have proven prophylactic properties, with a low sugar content and without palm oil. The quality of the elaborated walnut paste was determined and monitored during the shelf life in terms of oxidative stability (Acidity index (FFA) and Peroxide value (PV)), total phenols content, antioxidant activity and rheology. The obtained results demonstrated that during 4 months of storage the acidity index of the walnut paste did not register significant changes, reaching maximum values of 0.17±0,01 (Oleic g/100 g), while the peroxide values evolved up to 2.22±0,03 meq/kg oil. The slow evolution of the oxidative parameters can be due to the phenolic compounds in walnut paste that recorded a value of 47.2±0,36 mg GAE/g with an antioxidant activity (DPPH free radical scavenging) of 70±1,02 %. Concerning sensory characteristics, the walnut paste samples were positively appreciated in comparison with Nutella and no significant quality difference was observed after storage for 4 months.

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Section: Oxidative Stabilitymentioning

confidence: 99%

Walnut Paste: A Healthy Alternative for Nutella Consumers

Covaliov¹,

Siminiuc²,

POPOVICI³

2023

EPHELS

View full text Add to dashboard Cite

show abstract

“…Numerous studies have evidenced that walnut oil can prevent cardiovascular diseases, including hypertension (Li et al., 2020) and coronary heart disease (Virtanen, 2018). Walnut oil, renowned for its bioactive compounds, such as phytosterols, tocopherols, polyphenols, and flavones, has recently gained popularity (Ampofo et al., 2022; Bi et al., 2022; Gao et al., 2022).…”

Section: Introductionmentioning

confidence: 99%

Comparison of chemical compositions and aroma characteristics of walnut oil prepared by different roasting processes

Lu,

Gao,

et al. 2024

Journal of Food Science

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Walnut oil is an edible oil with high nutritional value, and the roasting process influences its quality and flavor. This study aimed to investigate the effects of roasting on the fatty acid composition, bioactive compounds (tocopherols, polyphenols, and phytosterols), and antioxidant capacity of walnut oil. Additionally, the aroma compounds and sensory characteristics were evaluated to comprehensively assess the variations in walnut oil after roasting. Roasting resulted in no notable impact on the fatty acid composition of walnut oil but increased the content of tocopherols and polyphenols in walnut oil, increasing its antioxidant capacity. Heavy roasting (160°C/20 min) reduced the phytosterol content in walnut oil by 2.3%. In total, 146 volatile compounds were detected in both cold‐pressed and roasted walnut oil using headspace solid‐phase microextraction‐gas chromatography–mass spectrometry, and 32 key aroma compounds were identified. Aromatic aldehydes, aliphatic aldehydes, and heterocyclic compounds significantly contributed to fragrant walnut oil. Furthermore, the principal component analysis based on quality characteristics and sensory evaluation indicated that moderate roasting (130°C/20 min, 130°C/30 min, and 160°C/10 min) provided walnut oil with a sweet, nutty, and roasted aroma, as well as high levels of linoleic acid, phytosterols, and γ‐tocopherol. Although heavy roasting (160°C/15 min and 160°C/20 min) enhanced the antioxidant capacities of walnut oils due to high levels of polyphenols, the oils exhibited an unpleasant burnt aroma. This study showed that roasting promoted the quality and flavor of walnut oil, and moderate conditions endowed walnut oil with a characteristic‐rich flavor while maintaining excellent quality.

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“…In addition to water (3-5%), walnuts contain proteins (12-25%), polyunsaturated fatty acids (omega 3 and omega 6), biogenic amines (melatonin and serotonin), vitamins (B, C, E, and P complex), minerals (magnesium, potassium, calcium, iron, zinc), polyphenols, and fiber [1,3,6,7]. Topala et al (2020) [8] cites authors that justified the classification of the walnut as a strategic nut crop for human nutrition as well as the inclusion in the dedicated FAO list of priority plants.…”

Section: Introductionmentioning

confidence: 99%

Effect of Temperature and Storage Time on Some Biochemical Compounds from the Kernel of Some Walnut Cultivars Grown in Romania

et al. 2023

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Walnut kernels are appreciated not only for their mineral content, vitamins, proteins, and valuable lipids, but also for the presence of polyphenolic compounds and biogenic amines. The temperature and storage time effects on some biochemical compounds from kernels collected from eight walnut genotypes grown at the Fruit Growing Research and Extension Station (SCDP) Valcea, Romania, were studied. In general, the phenolic and carotenoid compounds followed opposite trends during short-term storage and in some cases in medium-term storage. In both cases, there was a reduction in concentration during long-term storage, which was more pronounced for carotenoids. The most efficient method for preserving the walnut kernel’s phenolic content was freezing. Keeping the walnut kernel at room temperature assured the smallest carotenoid content decrease. Depending on the walnut cultivar, the preservation of the walnut kernel can be extended to five months by storage at −20 to −18 °C without loss of phenolic compounds, while a period shorter than five months (but certainly longer than three months) could be recommended for storage at 3–4 °C. Keeping it at room temperature can be an option for a short period (about three months). None of the preservation methods was adequate if the losses recorded for carotenoids were taken into account.

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Oxidative Stability of Walnut Kernel and Oil: Chemical Compositions and Sensory Aroma Compounds

Cited by 8 publications

References 42 publications

Walnut Paste: A Healthy Alternative for Nutella Consumers

Walnut Paste: A Healthy Alternative for Nutella Consumers

Comparison of chemical compositions and aroma characteristics of walnut oil prepared by different roasting processes

Effect of Temperature and Storage Time on Some Biochemical Compounds from the Kernel of Some Walnut Cultivars Grown in Romania

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