scholarly journals 106 Cellulose Coatings Reduce Rancidity of Pecans

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 407B-407
Author(s):  
E.A. Baldwin ◽  
Bruce W. Woods

Pecans (Carya illinoinensis) are full of unsaturated fatty acids, which are subject to oxidative cleavage. This results in the development of rancid off-flavors, which render the nuts unmarketable. For this reason, pecans must be stored under costly refrigerated conditions. Furthermore, pecans usually undergo retail distribution and marketing at ambient conditions, which promote development of off-flavors. Application of cellulose-based edible coatings reduced off-flavor, and improved overall flavor scores while adding shine to the nuts during 14 months of storage under ambient conditions. Development of rancidity involves hydrolysis of glycerides into free fatty acids, oxidation of double bonds of unsaturated fatty acids to form peroxides and then autooxidation of the free fatty acids once the peroxides reach a sufficient level to perpetuate this reaction. One of the products of autooxidation is hexanal which is, thus, a good indicator of rancidity. Analysis of pecans by gas chromatography revealed that hexanal levels were reduced in coated nuts by 5- to over 200-fold compared to uncoated controls, depending on the coating treatment. Some of the coating treatments affected nut color, but overall flavor and appearance were improved by certain formulations.

HortScience ◽  
2006 ◽  
Vol 41 (1) ◽  
pp. 188-192 ◽  
Author(s):  
Elizabeth A. Baldwin ◽  
Bruce Wood

Unsaturated fatty acid oxidation results in rancid off-flavors in pecan [Carya illinoinensis(Wangenh.) K. Koch] kernels, which shortens shelf life under ambient conditions. For this reason kernels are stored under costly refrigeration. Edible coatings [hydroxypropyl cellulose (HPC) and carboxymethyl cellulose (CMC), plus various additives] were used to restrict oxygen contact with kernel associated fats by acting as a barrier to gas exchange. Fresh pecans were acquired from orchards, air-dried, shelled, and treated with various coating formulations. The kernels were then drained, dried, and stored several months in open air or perforated zip-lock plastic bags at 20 to 25 °C and periodically evaluated by 18 to 20 sensory panelists using a 9-point hedonic scale for appearance, shine, off-flavor or overall flavor, and texture. Coated kernels generally scored lower for off-flavor, and higher for overall flavor. Preliminary coatings resulted in a less preferred appearance, but modifications to formulations of subsequent coatings resulted in either improved appearance or had no effect on appearance of kernels compared with uncoated control. Coatings with CMC imparted a shine to coated kernels, but did not generally affect texture. Hexanal accumulation, a good indicator of rancidity, of the homogenate of kernels stored at ambient temperatures for 5 and 9 months was lower in kernels coated with CMC than in the uncoated control, with CMC coatings including α-tocopherol being most effective. Thus, CMC-based coatings exhibit potential for extending the shelf life of pecan kernels.


2021 ◽  
Vol 2 (1) ◽  
pp. 74-91
Author(s):  
Beatrice Casali ◽  
Elisabetta Brenna ◽  
Fabio Parmeggiani ◽  
Davide Tessaro ◽  
Francesca Tentori

The review will discuss the methods that have been optimized so far for the enzymatic hydrolysis of soapstock into enriched mixtures of free fatty acids, in order to offer a sustainable alternative to the procedure which is currently employed at the industrial level for converting soapstock into the by-product known as acid oil (or olein, i.e., free fatty acids removed from raw vegetable oil, dissolved in residual triglycerides). The further biocatalyzed manipulation of soapstock or of the corresponding acid oil for the production of biodiesel and fine chemicals (surfactants, plasticizers, and additives) will be described, with specific attention given to processes performed in continuous flow mode. The valorization of soapstock as carbon source in industrial lipase production will be also considered.


Author(s):  
Catherine E. Allen ◽  
Paul A. Tyler ◽  
Cindy L. Van Dover

Specimens of the chemoautotrophic symbiont-bearing hydrothermal vent clam Calyptogena pacifica were collected from hydrothermal vents at the Endeavour segment of the Juan de Fuca Ridge. Total lipid was extracted from gill, foot and mantle tissues, and lipid class and fatty acid composition determined by thin layer chromatography with flame ionization detection (TLC–FID), gas chromatography (GC) and gas chromatography with mass spectrometry (GC–MS). An abundance of n–7 monounsaturated fatty acids (MUFA), especially in the gill, reflected the large contribution of chemoautotrophic symbiotic bacteria to the nutrition of this clam. The absence of n–8 MUFA suggests that C. pacifica does not contain methanotrophic symbiotic bacteria. Low levels of highly unsaturated fatty acids (HUFA) such as 20:5 n–3 and 22:6 n–3 were detected in C. pacifica and their presence is attributed to a source other than chemoautotrophic symbiotic bacteria. Significant levels of non-methylene interrupted dienoic fatty acids and eicosatrienoic acid (20:3) were also detected in C. pacifica and it is suggested that these fatty acids are synthesized from n–7 MUFA as alternatives to HUFA. In contrast to shallow water bivalves, elevated levels of triglyceride were detected in the gills compared to the mantle.


1964 ◽  
Vol 36 (12) ◽  
pp. 2244-2248 ◽  
Author(s):  
J. G. Nikelly

1997 ◽  
Vol 273 (1) ◽  
pp. G184-G190 ◽  
Author(s):  
M. Saghir ◽  
J. Werner ◽  
M. Laposata

Fatty acid ethyl esters (FAEE), esterification products of fatty acids and ethanol, are in use as fatty acid supplements, but they also have been implicated as toxic mediators of ethanol ingestion. We hypothesized that hydrolysis of orally ingested FAEE occurs in the gastrointestinal (GI) tract and in the blood to explain their apparent lack of toxicity. To study the in vivo inactivation of FAEE by hydrolysis to free fatty acids and ethanol, we assessed the hydrolysis of FAEE administered as an oil directly into the rat stomach and when injected within the core of low-density lipoprotein particles into the circulation of rats. Our studies demonstrate that FAEE are rapidly degraded to free fatty acids and ethanol in the GI tract at the level of the duodenum with limited hydrolysis in the stomach. In addition, FAEE are rapidly degraded in the circulation, with a half-life of only 58 s. Thus the degradation of FAEE in the GI tract and in the blood provides an explanation for the apparent lack of toxicity of orally ingested FAEE.


1972 ◽  
Vol 55 (5) ◽  
pp. 975-978
Author(s):  
J G Navarro ◽  
F Borie ◽  
J Saavedra

Abstract A residual lipid which is not removed by solvent extraction was detected and determined after enzymatic hydrolysis of defatted egg yolk protein. Free fatty acids were found to be the type of lipid bonded to the egg yolk protein. The mode of attachment of these fatty acids to the egg yolk protein is suggested and the composition of the fatty acids is reported.


1969 ◽  
Vol 52 (5) ◽  
pp. 904-910 ◽  
Author(s):  
Garnett Wood ◽  
Lane Hintz ◽  
Harold Salwin

Abstract Chemical changes that occur in the proteins, nucleotides, and lipids of fish tissue during storage at low temperatures were investigated. Homogenized tissue, prepared from fresh rock-fish (striped hass, Roccus species), was stored up to six days at temperatures from -10° to 4°C and then analyzed. At 0°C and below, the solubility of myofibrillar proteins decreased. There were also changes in polyacrylamide gel electrophoretic patterns of protein extracts. The total nucleotide content decreased rapidly at all temperatures. The lipids were extracted from each sample and separated into neutral lipids, phospholipids, and free fatty acids by column chromatography. The fatty acid composition of each fraction was determined by gas chromatography. In the fresh tissue, polyunsaturated acids occurred in greatest proportion in the free fatty acid and phospholipid fractions, whereas inono-unsaturated acids were inofe highly concentrated in the neutral lipids. The percentages of saturated acids were approximately the same in all fractions. During storage, there were considerably larger losses of individual acids from phospholipids than from neutral lipids. The polyunsaturated acids of the phospholipid fraction were affected most. Over 10% of these aeids were lost in six days at ice temperature, but only a small proportion of the losses was accounted for by increases in free fatty acids. Oxidative proo esses may account for the imbalance because the rate of oxidation, as measured by the thio-barbituric acid test, increased with storage temperature in the same manner as the rale at which unsaturated fatty acids were lost from the pliospliolipuls. Losses of polyunsaturated acids from the neutral lipids were much smaller, suggesting a selectively protective mechanism or environment in that fraction. The changes in the phospholipid fatty acids may provide the basis for useful objective tests of fish lecomposilion.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1836
Author(s):  
Lijuan Han ◽  
Qingqing Han ◽  
Yongjing Yang ◽  
Honglun Wang ◽  
ShuLin Wang ◽  
...  

Characterization of the structure and pharmacological activity of Berberis dasystachya Maxim., a traditional Tibetan medicinal and edible fruit, has not yet been reported. In this study, central composite design (CCD) combined with response surface methodology (RSM) was applied to optimize the extraction conditions of B. dasystachya oil (BDSO) using the supercritical carbon dioxide (SC-CO2) extraction method, and the results were compared with those obtained by the petroleum ether extraction (PEE) method. The chemical characteristics of BDSO were analyzed, and its antioxidant activity and in vitro cellular viability were studied by DPPH, ABTS, reducing power assay, and MTT assay. The results showed that the maximum yield of 12.54 ± 0.56 g/100 g was obtained at the optimal extraction conditions, which were: pressure, 25.00 MPa; temperature 59.03 °C; and CO2 flow rate, 2.25 SL/min. The Gas chromatography (GC) analysis results showed that BDSO extracted by the SC-CO2 method had higher contents of unsaturated fatty acids (85.62%) and polyunsaturated fatty acids (57.90%) than that extracted by the PEE method. The gas chromatography used in conjunction with ion mobility spectrometry (GC–IMS) results showed that the main volatile compounds in BDSO were aldehydes and esters. BDSO also exhibited antioxidant ability in a dose-dependent manner. Moreover, normal and cancer cells incubated with BDSO had survival rates of more than 85%, which indicates that BDSO is not cytotoxic. Based on these results, the BDSO extracted by the SC-CO2 method could potentially be used in other applications, e.g., those that involve using berries of B. dasystachya.


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