Exploring the Role of Lipoxygenases on Walnut Quality and Shelf-Life

Piccirillo, Pasquale; Fasano, Pasqua; Mita, D.G.; Paolis, Angelo De; Santino, Angelo

doi:10.17660/actahortic.2005.705.79

Cited by 8 publications

(7 citation statements)

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“…Accumulation of these volatiles was associated with the increase in activities of enzymes from the LOX pathway in young coconut fruit after harvest (Meethaworn et al, 2019). Similar results were reported in cucumber (Mao et al, 2007;Yang et al, 2012) olive fruit (Padilla et al, 2014) and walnut (Piccirillo et al, 2006) during storage at low temperatures. Downstream in the LOX pathway, hydroperoxide lyase (HPL) hydrolyzes in hydroperoxides into aldehyde.…”

Section: Introductionsupporting

confidence: 81%

Off-flavor and Loss of Aroma in Young Coconut Fruit During Cold Storage are Associated with the Expression of Genes Derived from the LOX Pathway and <i>Badh2</i>

et al. 2022

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Dissatisfaction with the flavor quality of young aromatic Thai coconut 'Nam-Hom' usually grows when stored at 2-4°C after harvest, represented by off-flavor development and aroma loss. To understand the mechanism of postharvest flavor deterioration, young coconut fruit were stored at 4°C and 25°C for 15 days. Sensory evaluation was performed, volatile compositions were analyzed, enzyme activities and transcript levels of genes related to the synthesis of volatiles were investigated. Off-flavor was observed after six days of storage at 4°C and tended to be more serious after that. A total of 45 volatiles were identified in the young coconut fruit. Partial least square discriminant analysis (PLS-DA) revealed two volatiles, 1-heptanol, 1-octanol, and nonanal, which were associated with off-flavor development. Transcript levels of CnLOX1, CnHPL1, and CnADH2, relating to the volatile production catalyzed by the LOX pathway, increased during storage at low temperatures. Their respective enzyme activities were also found to increase. The loss of the aromatic nature of young 'Nam-Hom' coconut at 4°C was found to be associated with an increase in CnBadh2 gene expression, resulting in a lower 2-acetyl-1-pyrroline (2-AP) content as compared to that at 25°C. Wrapping the fruit with polyethylene (PE) instead of polyvinyl chloride film reduced the off-flavor by reducing the oxygen concentration; consequently, this prevented enzyme activities and expression of genes from the LOX pathway. However, the loss of the aromatic nature of young 'Nam-Hom' coconut fruit at low temperature storage could not be mitigated with PE packaging.

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Section: Introductionsupporting

confidence: 81%

Off-flavor and Loss of Aroma in Young Coconut Fruit During Cold Storage are Associated with the Expression of Genes Derived from the LOX Pathway and <i>Badh2</i>

et al. 2022

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“…13-LOXs give origin to hexanal and (E) -2-hexenal, two volatiles included in this study. Moreover, walnuts are known for their prevalence of 13-LOXs compared to those observed in other nuts, such as almonds [ 31 , 54 ]. Therefore, the baseline concentration of hexanal in kernel samples may be generated through the lipoxygenase pathway during kernel processing (e.g., drying).…”

Section: Resultsmentioning

confidence: 99%

Walnut (Juglans regia L.) Volatile Compounds Indicate Kernel and Oil Oxidation

Grilo

Wang

2021

Foods

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Kernel oxidation susceptibility and pellicle darkening are among the biggest concerns regarding walnut quality. Monitoring oxidation is crucial to preserve quality from production to consumption. Chemical oxidation parameters (peroxide value and UV absorbances), fatty acid profile, tocopherols, phenols, and volatiles in ‘Chandler’ and ‘Howard’ kernels were studied at different time points during 28 weeks of storage to evaluate potential oxidation markers. During storage, peroxide value, UV absorbances, and volatiles concentration increased; oxidative stability, phenols, and tocopherols decreased, while fatty acid profile was unaffected. ‘Chandler’ had a lower peroxide value, K232, and K268; and higher kernel and oil oxidative stability compared to ‘Howard’. Phenols and tocopherols decreased 1.2-fold in ‘Chandler’ and 1.3-fold in ‘Howard’. Using multivariate analysis, samples were discriminated in three groups according with their oxidative levels. Increases of volatiles in oil and kernel were associated with higher oxidative levels. Pentanal, 2-methylpropanal, hexanal, (E)-2-pentenal, 3-octanone, octanal, (Z)-2-penten-1-ol, hexanol, (E)-2-octenal, 1-octen-3-ol, benzaldehyde, (E,E)-2,4-nonadienal, and hexanoic acid in kernels were adequate at distinguishing oxidation levels and as oxidative markers in walnuts. Kernel volatiles is a useful measurement for walnut oxidation during storage without any prior fat extraction.

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“…In walnuts, light kernel colour is a crucial sensory factor for the consumer preference. Oxidative rancidity and browning deteriorate the sensory and nutritional quality of walnut and cause their unpleasant off-flavour and shorten their shelf life, which is also unsafe to consumer health (5,6).…”

Section: Introductionmentioning

confidence: 99%

Influence of Gum Arabic Enriched with GABA Coating on Oxidative Damage of Walnut Kernels

Ebrahimzadeh

Pirzad

Tahanian

et al. 2019

Food technol. biotechnol. (Online)

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Because of the higher content of unsaturated fatty acids (UNSFA) and phenolics, walnut kernels are vulnerable to oxidative rancidity and browning due to unfavorable postharvest handling procedures. This study investigates the impact of gum arabic coating enriched with γ-aminobutyric acid (GABA) on oxidative rancidity and browning of kernels during storage at 20 °C. The results showed that the walnut kernels coated with gum arabic (5 %) enriched with GABA (0.1 mM) exhibited lower oxidative rancidity and browning, manifested by lower peroxide value and malondialdehyde accumulation along with higher whiteness index. Moreover, kernels had higher UNSFA/SFA ratio as a response to lower lipoxygenase activity and H2O2 accumulation. The reduced oxidative browning in coated kernels was accompanied with lower polyphenol oxidase and higher phenylalanine ammonia-lyase activity leading to higher accumulation of phenolics and increased DPPH• scavenging capacity. Based on our findings, gum arabic coating (5 %) enriched with GABA (0.1 mM) may have a commercial potential for maintaining nutritional quality of walnut kernels.

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Exploring the Role of Lipoxygenases on Walnut Quality and Shelf-Life

Cited by 8 publications

References 0 publications

Off-flavor and Loss of Aroma in Young Coconut Fruit During Cold Storage are Associated with the Expression of Genes Derived from the LOX Pathway and <i>Badh2</i>

Off-flavor and Loss of Aroma in Young Coconut Fruit During Cold Storage are Associated with the Expression of Genes Derived from the LOX Pathway and <i>Badh2</i>

Walnut (Juglans regia L.) Volatile Compounds Indicate Kernel and Oil Oxidation

Influence of Gum Arabic Enriched with GABA Coating on Oxidative Damage of Walnut Kernels

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