Oxidative rancidity in nuts

Shahidi, Fereidoon; John, J. E. A.

doi:10.1533/9780857097484.2.198

Cited by 26 publications

(45 citation statements)

References 105 publications

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“…37 Organic acids such as hexanoic acid possess penetrating goaty, sweaty, and cheesy aromas, and 2-pentylfuran has a beany and metallic character. At a certain abundance, all of these compounds would contribute non-natural aroma to almonds and are therefore considered deleterious to almond aroma, 5 offering support to the significant negative correlation these compounds have with liking. The significant decrease in average liking of DR and LR almonds at two months of storage and concurrent change in volatiles may offer insight into the phenomenon termed "flavor fade" in peanuts.…”

Section: And 2)mentioning

confidence: 97%

Chemical and Sensory Characterization of Oxidative Changes in Roasted Almonds Undergoing Accelerated Shelf Life

Franklin

Chapman

King

et al. 2017

J. Agric. Food Chem.

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In almonds, there is no standard method for detecting oxidative changes and little data correlating consumer perception with chemical markers of rancidity. To address this, we measured peroxide values (PV), free fatty acid values (FFAs), conjugated dienes, tocopherols, headspace volatiles, and consumer hedonic response in light roasted (LR) and dark roasted (DR) almonds stored under conditions that promote rancidity development over 12 months. Results demonstrate that, although rancidity develops at different rates in LR and DR almonds, consumer liking was not significantly different between LR and DR almonds. Average hedonic ratings of almonds were found to fall below a designated acceptable score of 5 ("neither like nor dislike") by 6 months of storage. This did not correspond with recommended industry rejection standard of PV < 5 mequiv peroxide/kg oil and FFA < 1.5% oleic. FFAs remain well below <1.5% oleic during storage, indicating that FFAs are not a good marker of rancidity in roasted almonds stored in low humidity environments. Regression of consumer liking to concentration of rancidity indicators revealed that selected headspace volatiles, including heptanal, octanal, nonanal, 2-octenal, 2-heptanone, 2-pentylfuran, hexanal, and pentanal, had a better correlation with liking than did nonvolatile indicators.

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Section: And 2)mentioning

confidence: 97%

Chemical and Sensory Characterization of Oxidative Changes in Roasted Almonds Undergoing Accelerated Shelf Life

Franklin

Chapman

King

et al. 2017

J. Agric. Food Chem.

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“…The high content of unsaturated fatty acids found in almonds, like most nuts, makes them susceptible to oxidation and to important quality losses if stored improperly or for too long. However, the specific rate of oxidation and flavor deterioration of a nut will be dependent on the distribution of individual fatty acids and other factors (Hudson & Gordon, ; Shahidi & John, ). In general, almonds maintain quality throughout storage better than some nuts, due to their low‐moisture and high antioxidant content (Huang, ; Shahidi & John, ).…”

Section: Introductionmentioning

confidence: 99%

“…As harvest season for almonds occurs only once per year, the determination of optimal storage conditions is important to the prevention of deterioration in quality during storage and shipment (Shahidi & John, ). Over 82% of the world's almond production occurs in California, with approximately 2/3 of the almonds being shipped internationally (Almond Board of California, ).…”

Section: Introductionmentioning

confidence: 99%

“…Harvested almonds are also transported and marketed in a variety of forms, which influence product stability. These forms include in‐shell, shelled kernels, and peeled seeds; whole or nut pieces; and raw and roasted nuts (Harris & Ferguson, ; Shahidi & John, ). It is known that the degree of processing plays a role in the rate of quality deterioration due to oxidation or rancidity development (Huang, ).…”

Section: Introductionmentioning

confidence: 99%

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Effects of Storage Conditions on Consumer and Chemical Assessments of Raw ‘Nonpareil’ Almonds Over a Two‐Year Period

Pleasance

Kerr

Pegg

et al. 2018

Journal of Food Science

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Raw almonds are a major commodity, yet much is unknown about how storage conditions determine their shelf life. The storage stability, as measured by consumer assessments and chemical measures, of raw almonds was determined for samples stored in cardboard boxes and polypropylene packaging for 2 years at 4, 15, 25, and 35 °C, and at 50% and 65% relative humidity (RH). Samples stored in unlined cartons always failed (>25% rejection) before their counterparts stored in polypropylene bags under identical environmental conditions. Models determined that polypropylene packaging (as opposed to unlined cardboard cartons) extended the time until sample rejection by more than 7 months. Temperature and RH were both negatively associated with storage time until failure. Flavor was a greater contributor to consumer acceptability than texture or odor, while peroxide values and free fatty acids were of greater importance in predicting raw almond consumer quality than measures of conjugated dienes or 2‐thiobarbituric acid‐reactive substances.Practical ApplicationThe results of this study will allow almond producers to determine packaging types and environmental storage conditions that provide shelf life of a specified time.

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“…In turn, oxidative rancidity can occur, when the double bonds of the unsaturated fatty acids are oxidized in the presence of oxygen to peroxides or hydroperoxides that give rise to aldehydes, ketones, etc. Due to this, it is important to evaluate the oil physicochemical changes to predict the shelf life and in which stage of its storage it is convenient to use them as precursors of the polyols [3,4] .…”

Section: Introductionmentioning

confidence: 99%

Alternative use of oily fractions of olive oil

2019

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Oily fractions of olive oil not suitable for human consumption used were: lamp oil (AL), olive pomace oil (OO) and clear oil lees (CB). Polyols were obtained by modifications of epoxidation with subsequent hydrolysis (ALH, OOH, CBH) and transesterification (ALHT, OOHT, CBHT) in order to favor, then, the polymerization reactions. The analysis of the physicochemical properties determined show the decrease of the unsaturations in the triglyceride and the increase of the OH concentration in the modified polyols as compared to the initial oils (from 16 to 380 for the AL and the ALHT; from 24 to 448 for the CB and the CBHT and from 3 to 430 for the OO and the OOHT, respectively) .The main objective of this work is to evaluate the stability of these oils over time and to provide an alternative synthesis of polyurethanes from a renewable resource, not previously used for this purpose.

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Oxidative rancidity in nuts

Cited by 26 publications

References 105 publications

Chemical and Sensory Characterization of Oxidative Changes in Roasted Almonds Undergoing Accelerated Shelf Life

Chemical and Sensory Characterization of Oxidative Changes in Roasted Almonds Undergoing Accelerated Shelf Life

Effects of Storage Conditions on Consumer and Chemical Assessments of Raw ‘Nonpareil’ Almonds Over a Two‐Year Period

Alternative use of oily fractions of olive oil

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