Volatile Lipid Oxidation Research Articles

The impact of hempseed dehulling on chemical composition, structure properties and aromatic profile of hemp protein isolate

Hempseed protein has attracted increasing attention in both scientific and industrial field because of its high nutritional value. In the current study, the influence of dehulling process on the chemical composition, structure and functional properties of hempseed protein isolate (HPI) was determined by using SDS-PAGE, SEC-HPLC-UV/RI/MALS, CD spectroscopy and DSC. The result demonstrated that dehulling process significantly increased the extraction and protein recovery yields of HPI. Meanwhile, dehulled HPI also exhibited a higher protein purity and Arg/Lys ratio with improved color. No significant impact on protein composition and structure was observed upon seed dehulling, but HPI extracted from the dehulled seeds showed a reduced thermal stability as compared to non-dehulled HPI. The aromatic profile of HPI was determined by HS-SPME-GC-MS, and the data suggested that dehulled HPI accumulated more terpenes and less lipid oxidation volatiles than non-dehulled HPI. These findings indicated that dehulling process greatly enhances the extraction yield with higher protein content and more characteristic aroma of HPI. The current study for the first time provides valuable information about the influence of dehulling processing on the properties of HPI, which will facilitate further research and application of hempseed and its valued added ingredients in both academic and industry field.

Protein-lipid co-oxidation in emulsions stabilized by microwave-treated and conventional thermal-treated faba bean proteins.

The course of protein–lipid co‐oxidation was investigated in oil‐in‐water emulsions stabilized with proteins extracted from microwave‐treated (MWT) and conventional thermal‐treated (CTT) faba beans stored at 37°C for 7 days. Emulsions prepared with proteins from untreated (UT) faba beans and soy protein isolate (SP) were monitored for comparison. Lipid oxidation was detected through formation of primary and secondary oxidation products while protein oxidation was examined via tryptophan fluorescence degradation in interface and aqueous phase. Oxidation of proteins was more emphasized in the interfacial layers of MWT, CTT, and SP emulsions than in UT emulsions due to the prominence of radical chain‐driven co‐oxidation mechanism while lipoxygenase (LOX) activity in UT and MWT emulsions resulted in high amounts of hydroperoxides and abundance in lipid oxidation volatiles. Conventional thermal treatment provided better oxidative stability than microwave treatment reflected in lower levels of hydroperoxides and relative lack of diversity in lipid volatiles. Among detected volatiles, formation of ketones was more distinguished in MWT, CTT, and SP emulsions while UT emulsions contained a more diverse range of alkenals and alkanals. Ketones are known to form mainly through radical recombination reactions which combined with the results of protein oxidation supports that radical transfer reactions between proteins and lipids were the driving force behind oxidation in MWT, CTT, and SP emulsions. Treatments of faba beans resulted in increased oxidative stability of emulsified lipids and lower degradation of aqueous phase proteins.

Effect of Cooking Methods on the Flavor of Jinhua Ham by GC-MS and Electronic Nose Analysis

Jinhua ham is popular in China because of its characteristic aroma. Unlike dry-cured western ham, it is cooked. The objective of this study was to evaluate the effect of three traditional cooking methods, steaming (B), boiling (C) and stewed ham Soup (S) on the volatiles in Jinhua ham (A). The volatiles were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) after extraction by Solid Phase Microextraction (SPME). The volatiles mainly consisted of alcohols, sulfur-containing compounds and cyclic compounds. Results from the Principal Components Analysis (PCA) showed A, C1, C3 (13, 18), B1, B2 (13) had the same volatiles, while B3 (22, 24, 36, 12, 30, 19, 23, 26), C2 (28, 33) and S1 (37, 27, 38), S3 (38, 8, 34); S2 (8, 17, 11) showed negative correlation with A, C1, C3, B1 and B2. The compounds generated by cooking the ham were dominated by Maillard reaction and lipid oxidation volatiles. Most importantly, many unsaturated hydrocarbons, such as 3-methyl-2- butenal, 2-heptenal were generating by different types of heating. The electronic nose analysis indicated that the cooking methods had great effect on the flavor profiles of the ham. The C2 appeared to have profile similar to the raw ham. However, C3 had different flavor profile from that for S1 and S2. The main source of the difference was that the profiles appeared to be high in sulfur-containing content in S1 and S2.

Critical evaluation of non-thermal plasma as an innovative accelerated lipid oxidation technique in fish oil

Food products enriched with healthier unsaturated fatty acids are more sensitive to lipid oxidation, leading to an overall quality deterioration and the development of unwanted aroma properties. To evaluate the oxidative stability a wide range of techniques has been described in literature, of which most are thermally based. These unrealistic test conditions result in the induction of deviating oxidation chemistry compared to that observed during ambient storage. Non-thermal plasma technology is capable to generate a wide range of highly reactive oxidative species (e.g. atomic oxygen, hydroxyl radicals, singlet oxygen) while maintaining ambient temperatures. For the first time, a DBD-plasma jet (Ar/0.6% O2) is used on fish oil samples as a faster and more realistic accelerated lipid oxidation method. This paper critically evaluates both a thermal as a non-thermal plasma based accelerated oxidation protocol using naturally aged fish oil as reference. Experiments were done using both virgin, as alpha-tocopherol-enriched fish oil samples. Secondary lipid oxidation volatiles were measured using HS-SPME–GC–MS. Both accelerated oxidation techniques induced the formation of typical lipid oxidation markers (e.g. 2-propenal, (E)-2-pentenal, heptanal), however in both cases significant differences were observed compared to the naturally aged fish oil. On the other side, non-thermal plasma correctly predicted an antioxidative effect when 1000μg/g alpha-tocopherol was added to the fish oil, while thermally based tests resulted in the induction of prooxidative chemistry. Despite the differences with naturally aged fish oil, several non-thermal plasma characteristics (reactor configuration, gas feed mixture, power source, …) can be fine-tuned to evolve towards a technology that is capable to accelerate lipid oxidation in a highly realistic manner.

The “True” Neapolitan Pizza: Assessing the Influence of Extra Virgin Olive Oil on Pizza Volatile Compounds and Lipid Oxidation

The aim of our research was to evaluate the effect of different types of vegetable oils, namely extra virgin olive oil (EVOO), olive oil, and sunflower oil, on the chemical properties and volatile profile of traditional Neapolitan pizza, produced by using tomato sauce and EVOO. The quality indices and polyphenols in vegetable oils were analyzed to assess the lipid oxidation as affected by cooking in traditional wood-fired ovens. Peroxide value significantly increased in all vegetable oils, particularly in sunflower oil. EVOO polyphenols decreased about 30% their initial level, particularly simple phenolics. Total individual phenolic compounds decreased from 254.6 to 172.0 mg/kg. Pizza cooking caused the development of some neo-formation volatile compounds caused by lipid oxidation and Maillard reaction. Some positive key odor compounds were found in pizza cooked with EVOO, and the addition of tomato sauce and EVOO caused a dramatic change in its volatile pattern.

Quality Changes in Gamma Irradiated Marinades of Anchovy (Engraulis anchoita) During Refrigerated Storage

The effect of gamma irradiation (0, 1.8, and 3.3 kGy) on the microbiological, chemical, and color characteristics of marinated (7% acetic acid and 10% NaCl) and vacuum-packed anchovy fillets was analyzed during 20 months of refrigerated storage (4 ± 1°C). Acidity, pH, water activity (aw), total volatile basic nitrogen (TVBN), lipid oxidation, and color parameters were determined. Mesophilic and psychrotrophic bacteria, sulphite-reducing clostridia, total and fecal coliforms, Staphylococcus spp., yeasts, and molds were investigated. Gamma irradiation reduced the initial mesophilic bacterial counts and inhibited mesophils growth during 20 months. As a result, the production of TVBN during storage was lower in irradiated samples than in control. Also, lipid oxidation was lower in irradiated samples than in nonirradiated. The color of anchovy fillets was not affected by the irradiation treatment. Even if nonirradiated anchovy fillets presented a high stability in comparison with the traditional product (in flasks with vegetable oil and spices), gamma irradiation improved the microbiological and chemical quality of anchovy fillet marinades without inducing changes on its characteristic color for 20 months.

Lipid oxidation volatiles absent in milk after selected ultrasound processing

Ultrasonic processing can suit a number of potential applications in the dairy industry. However, the impact of ultrasound treatment on milk stability during storage has not been fully explored under wider ranges of frequencies, specific energies and temperature applications. The effect of ultrasonication on lipid oxidation was investigated in various types of milk. Four batches of raw milk (up to 2L) were sonicated at various frequencies (20, 400, 1000, 1600 and 2000kHz), using different temperatures (4, 20, 45 and 63°C), sonication times and ultrasound energy inputs up to 409kJ/kg. Pasteurized skim milk was also sonicated at low and high frequency for comparison. In selected experiments, non-sonicated and sonicated samples were stored at 4°C and were drawn periodically up to 14days for SPME–GCMS analysis. The cavitational yield, characterized in all systems in water, was highest between 400kHz and 1000kHz. Volatile compounds from milk lipid oxidation were detected and exceeded their odor threshold values at 400kHz and 1000kHz at specific energies greater than 271kJ/kg in raw milk. However, no oxidative volatile compounds were detected below 230kJ/kg in batch systems at the tested frequencies under refrigerated conditions. Skim milk showed a lower energy threshold for oxidative volatile formation. The same oxidative volatiles were detected after various passes of milk through a 0.3L flow cell enclosing a 20kHz horn and operating above 90kJ/kg. This study showed that lipid oxidation in milk can be controlled by decreasing the sonication time and the temperature in the system depending on the fat content in the sample among other factors.

The Influence of Bleaching Agent and Temperature on Bleaching Efficacy and Volatile Components of Fluid Whey and Whey Retentate

Fluid whey or retentate are often bleached to remove residual annatto Cheddar cheese colorant, and this process causes off-flavors in dried whey proteins. This study determined the impact of temperature and bleaching agent on bleaching efficacy and volatile components in fluid whey and fluid whey retentate. Freshly manufactured liquid whey (6.7% solids) or concentrated whey protein (retentate) (12% solids, 80% protein) were bleached using benzoyl peroxide (BP) at 100 mg/kg (w/w) or hydrogen peroxide (HP) at 250 mg/kg (w/w) at 5 °C for 16 h or 50 °CC for 1 h. Unbleached controls were subjected to a similar temperature profile. The experiment was replicated three times. Annatto destruction (bleaching efficacy) among treatments was compared, and volatile compounds were extracted and separated using solid phase microextraction gas chromatography mass spectrometry (SPME GC-MS). Bleaching efficacy of BP was higher than HP (P < 0.05) for fluid whey at both 5 and 50 °C. HP bleaching efficacy was increased in retentate compared to liquid whey (P < 0.05). In whey retentate, there was no difference between bleaching with HP or BP at 50 or 5 °C (P > 0.05). Retentate bleached with HP at either temperature had higher relative abundances of pentanal, hexanal, heptanal, and octanal than BP bleached retentate (P < 0.05). Liquid wheys generally had lower concentrations of selected volatiles compared to retentates. These results suggest that the highest bleaching efficacy (within the parameters evaluated) in liquid whey is achieved using BP at 5 or 50 °C and at 50 °C with HP or BP in whey protein retentate.

Effect of addition of commercial rosemary extracts on potent odorants in cooked beef

Solid-phase microextraction-gas chromatography-olfactometry (SPME-GCO) and aroma extract dilution analysis (AEDA) were applied to measure the effects of the addition of two commercial rosemary extracts (RE) on the potent odorants in cooked beef extracts (BE). On the basis of the results of SPME-GCO and AEDA, the addition of RE imparted sweet and floral notes to BE as a result of the addition of esters and terpenes of RE. In addition, RE suppressed the formation of odorants derived via lipid oxidation and Maillard reactions. The most potent lipid oxidation volatiles consisted of 1-octen-3-one (mushroom-like), (E)-2,4-epoxy-(E)-2-decenal (metallic), and eight different aldehydes (fatty). The Maillard reaction volatiles, necessary for typical cooked beef flavor, included compounds with meaty [2-methyl-3-furanthiol, 2-methyl-3-(methylthio)furan, 2-methyl-3-(methyldithio)furan], roasty (2-furanmethanethiol), caramel-like [4-hydroxy-2,5-dimethyl-3(2H)-furanone], baked potato-like [3-(methylthio)propanal], and spicy [3-hydroxy-4,5-dimethyl-2(5H)-furanone] attributes. The suppressive effects of RE may be caused by the action of antioxidative substances in RE alone or in combination with the pH increase in BE induced by the matrix components of RE.

An Analytical Approach for Fast Odour Evaluation of Recycled Food–Grade Paperboard Materials Using HS–SPME–MS‐Nose Technology

Recycled paperboard is frequently used as a raw material for food packaging. As consumers are becoming more sensitive to off‐flavours, paperboard packaging needs to contain a low‐odour potential when brought in contact with food products. As paperboard manufacturers, printing companies and food producers have a lack of time for solving off‐flavour problems, sensory testing and conventionally used gas chromatography–mass spectrometry (GC–MS) techniques are frequently too time consuming. To meet the needs of fast and reliable odour analysis of recycled paperboard, MS‐based electronic nose (MS‐nose) technology was evaluated in this study. As this technique is based on MS identification, chemical information of the volatiles could be obtained. A hyphenated configuration, consisting of a headspace solid phase microextraction (HS–SPME) autosampler coupled to an MS‐nose instrument, was discussed. The odorous volatiles of four recycled paperboard samples, obtained by GC–MS analysis, were used for feature selection of ion masses needed for statistical data analysis of the MS‐nose results. Besides, the sensitivity and the reliability of the HS–SPME technique were tested by the statistical correlation of the obtained GC–MS data with descriptive sensory test results. The HS–SPME–MS‐nose analysis of the paperboard samples resulted in an objective classification, based on differences between diagnostic mass fragments of lipid oxidation volatiles, volatiles formed by microbiological activity and residual ink and coating volatiles. On the basis of the obtained results, the MS‐nose approach could be used as a fast odour characterization technique for product quality control of cellulose‐based packaging materials. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Decrease in rice aroma after application of growth regulators

Aromatic rices (Oryza sativa L.) compared to the leading varieties are low-yielding, susceptible to lodging and prone to attack by a number of insect pests and diseases. Under these conditions, various agricultural chemicals such as fertilizers, pesticides and growth regulators have been used for their cultivation. Few investigations, however, have examined the influence of these chemicals on rice aroma and flavor. In this study, changes in rice aroma after treatment with gibberellic acid, paclobutrazol, 3-indole acetic acid, and a regulator mixture consisting of paclobutrazol, proline and zinc chloride were for the first time examined using two aromatic rice cultivars. Applications were carried out after 25% of panicles had emerged. We studied 12 odor-active compounds, extracted and identified using static headspace coupled with gas chromatography. At the concentrations tested, all treatments with growth regulators resulted in reduced aroma content that affected overall flavor. In a smelling evaluation, control samples were significantly higher in intensity than treated samples. The difference between the aromas of control and treated samples was largely related to 2-acetyl-1-pyrroline, the major rice aroma compound, and lipid oxidation volatiles. For instance, in the cultivar Guixiangzhan grown during the late season, gibberellic acid treatment decreased the content of 2-acetyl-1-pyrroline by 19%, 3-indole acetic acid by 9%, paclobutrazol by 22%, and the regulator mixture by 21% compared with the control. Similar trends were observed in the Peizaruanxiang cultivar, with decreases ranging from 10 to 24%. Our findings demonstrate that treatments with growth regulators inhibited the metabolic processes associated with the formation of volatile compounds.

Effect of nitrogen flushing and storage temperature on flavor and shelf-life of whole milk powder

The US industry standard for shelf-life of whole milk powder (WMP) is 6 to 9 mo, although previous research has demonstrated flavor changes by 3 mo at ambient storage. This study evaluated the influence of packaging atmosphere, storage temperature, and storage time on WMP shelf-life using sensory and instrumental techniques. Two commercial batches of WMP were repackaged in plastic laminate pouches with air or nitrogen and stored at 2°C or 23°C for 1 yr. Descriptive analysis was conducted using a 10-member trained panel; volatile analysis was performed using solid-phase microextraction with gas chromatography-mass spectrometry. Consumer acceptance (n=75) was conducted every 3 mo with reconstituted WMP and white and milk chocolate made from each treatment. Data were analyzed using ANOVA with Fisher's LSD, Pearson correlation analysis, and principal component analysis. Air-stored WMP had higher peroxide values, lipid oxidation volatiles, and grassy and painty flavors than nitrogen-flushed WMP. Storage temperature did not affect levels of straight chain lipid oxidation volatiles; 23°C storage resulted in higher cooked and milkfat flavors and lower levels of grassy flavor compared with 2°C storage. Consumer acceptance was negatively correlated with lipid oxidation volatiles and painty flavor. Nitrogen flushing prevented the development of painty flavor in WMP stored up to 1 yr at either temperature, resulting in chocolate with high consumer acceptance. Nitrogen flushing can be applied to extend the shelf life of WMP for use in chocolate; storage temperature also plays a role, but to a lesser extent.

Effect of Cold Storage and Packaging Material on the Major Aroma Components of Sweet Cream Butter

The major aroma compounds of commercial sweet cream AA butter quarters were analyzed by GC-olfactometry and GC-MS combined with dynamic headspace analysis (DHA) and solvent-assisted flavor evaporation (SAFE). In addition, the effect of long-term storage (0, 6, and 12 months) and type of wrapping material (wax parchment paper vs foil) on the aroma components and sensory properties of these butters kept under refrigerated (4 degrees C) and frozen (-20 degrees C) storage was evaluated. The most intense compounds in the aroma of pasteurized AA butter were butanoic acid, delta-octalactone, delta-decalactone, 1-octen-3-one, 2-acetyl-1-pyrroline, dimethyl trisulfide, and diacetyl. The intensities of lipid oxidation volatiles and methyl ketones increased as a function of storage time. Refrigerated storage caused greater flavor deterioration compared with frozen storage. The intensity and relative abundance of styrene increased as a function of time of storage at refrigeration temperature. Butter kept frozen for 12 months exhibited lower styrene levels and a flavor profile more similar to that of fresh butter compared to butter refrigerated for 12 months. Foil wrapping material performed better than wax parchment paper in preventing styrene migration into butter and in minimizing the formation of lipid oxidation and hydroxyl acid products that contribute to the loss of fresh butter flavor.

Effect of UV Irradiation on Cut Cantaloupe: Terpenoids and Esters

Recent studies demonstrated that ultraviolet (UV) radiation enhanced terpenoids and decreased esters in thin-sliced cantaloupe. In preliminary studies treating fresh juices with UV, terpenoid compounds that normally were not isolated, or found in minute quantities, were elevated and only low molecular weight alcohols, ketones, and aldehydes decreased. Subsequently terpenoid induction/oxidation in UV-treated cut cantaloupe was reinvestigated. UV exposure increased the concentrations of terpenoids in cantaloupe tissue. However, UV exposure alone was not the sole factor responsible for enhanced terpenoids. UV-enhanced terpenoid production appears to be both cultivar- and maturity-dependent. Concomitant decreases in the ester content of UV-treated samples occurred using a previously published system. Yet, we established that almost identical ester losses occurred in thinly sliced laminar tissue receiving 60 min UV or air exposure in an open system. Tissue samples that were exposed to UV in a closed system often did not suffer correspondingly equal ester loss. Marked tissue warming (4.3 +/- 0.5 degrees C in 60 min) occurred during UV treatments in thin-sliced tissue. Ester loss from cantaloupe tissue was caused by the experimental procedure, but not by UV treatment per se. These findings are supported by the observation that UV is not responsible for chemical transformations to ester bonds, esterase, and lipase decrease in stored cut cantaloupe, and no lipid oxidation volatiles were observed in thin-sliced control tissue, while oxidized terpenoids were recovered. Information gathered indicates that improper cutting, handling, sanitation treatment, and storage can radically alter the desirable volatile aroma profile in cut cantaloupe, and potentially lead to decreased consumer acceptance.

Volatile constituents of cooked bullfrog ( Rana catesbeiana) legs

Volatile extracts obtained from pressure-cooked bullfrog legs by simultaneous steam distillation and solvent extraction were analyzed by gas chromatography–mass spectrometry. Although the raw bullfrog legs used in this study contained 0.6% fat only, the extracts were dominated (qualitatively and quantitatively) by lipid oxidation volatiles such as alkanals, alkenals, alkadienals, alkanols and alkenols. Few Maillard volatiles were found, amongst them 2-acetylthiazole, the only sulfur-containing compound found in the extract. This profile of volatiles may be explained by the high proportion of phospholipids and low concentration of sulfur amino acid cystine in raw bullfrog meat, as previously reported by other researchers. Odour activity values (OAV) of volatiles were also estimated and major OAV compounds were: ( E, E)-2,4-decadienal, ( E, Z)-2,4-decadienal, ( E, Z)-2,6-nonadienal, 1-octanol, and ( E)-2-nonenal. Some of these potent unsaturated aliphatic aldehydes have also been associated with chicken flavour. This may contribute to flavour resemblances between bullfrog and chicken meat.

Modification of maillard browning in a microwaved glucose/glycine model system by water‐soluble natural antioxidants and foods containing them

AbstractInhibition of pyrazine formation by natural antioxidants and the foods containing them was measured in a microwaved glucose/glycine model system. Inhibition of lipid oxidation by the same materials was assayed in both bulk and emulsion systems. Pyrazines were determined by solid‐phase micro extraction followed by GC. Lipid oxidation volatiles were assayed by polyamide fluorescence produced by either a bulk oil display or a hematin‐ or 2,2′‐azobis‐(2‐amidino=propane) dihydrochloride‐accelerated lecithin or fish oil emulsion. It was shown that (i) the inhibition of pyrazine formation depends on high concentrations of water‐soluble antioxidants; (ii) such antioxidants occur naturally in some foods and are usually polyphenols; (iii) during pyrazine inhibition, oxidized polyphenols show enhanced nonfluorescing browning similar to enzymic browning products; (iv) monophenols, which structurally cannot form quinone polymers on oxidation, inhibit pyrazines with less browning; (v) during the final pyrazine‐forming phase of the Maillard reaction, polyphenolics and reducing agents such as glutathione and ascorbic acid are partially consumed with some nutritional loss; (vi) fruit powders of grape seed, grape skin, and red wine are highly pyrazine‐inhibitory, steeped blueberry strongly so, but plum purees are moderately pro‐pyrazine, and freeze‐dried vegetables strongly pro‐pyrazine; and (vii) black and green tea infusions are highly inhibitory, whereas spices have mixed effects.

Preservative Effect of Combined Propionic and Ascorbic Acids on Pork Meat Stored at 25°C

A potential method for improving the bacteriological quality of pork meat stored at the ambient temperatures found in developing countries has been studied. Raw minced pork (longissimus dorsi muscle) was treated with propionic acid alone and propionic and ascorbic acid in combination at concentrations that had a preservative effect, restricting populations of pathogenic and spoilage bacteria well below thresholds necessary for spoilage or damage to public health. A water-treated sample was used as the control. The 0.306 mol/liter propionic -0.043 mol/liter ascorbic acid combination reduced bacterial numbers for up to 8 days at 25 ± 1°C, without adversely affecting the color or odor of the meat. Minced pork treated with solutions of propionic acid at 0.136 and 0.410 mol/liter showed surface bleaching and an increase in lipid oxidation volatiles relative to the water-treated control sample.

Measuring Lipid Oxidation Volatiles in Meats

ABSTRACTA relatively simple, low cost vacuum distillation method for trapping and concentrating meat volatiles for identification and quantification by gas chromatography (GC) was developed. The method was used to measure the oxidative stability of cooked chicken meats from birds fed different diets. Volatiles were distilled under vacuum (&lt; 4 mm Hg) and absorbed onto a Sep‐Pak cartridge prior to GC. The method allowed the specific analysis of individual volatile products and total volatiles from lipid oxidation. The analytical data provided similar information to TBA numbers and sensory data relative to effectiveness of antioxidants in the diet for controlling oxidative deterioration of meat.

Development of a fluorescence sensor to monitor lipid oxidation. 1. Fluorescence spectra of chitosan powder and polyamide powder after exposure to volatile lipid oxidation products

The fluorescence spectra of chitosan and polyamide powder after exposure to lipid oxidation volatiles were obtained by solid-sample fluorescence spectrophotometry. Chitosan powder fluoresced after exposure to the volatile oxidation products from oxidizing methyl arachidonate and methyl linolenate. Chitosan powder also fluoresced after exposure to pure malonaldehyde vapor. Chitosan fluorescence after exposure to volatile malonaldehyde had an excitation maximum at 395 nm and an emission maximum at 460 nm

Development of a fluorescence sensor to monitor lipid oxidation. II. The kinetics of chitosan fluorescence formation after exposure to lipid oxidation volatiles

Abstract Chitosan was used as a basis for a fluorescence sensor to monitor volatile malonaldehyde production during lipid oxidation. The rate of chitosan fluorescence formation during exposure to volatiles generated during lipid oxidation depended on the extent of fluorescence formation to the one half power and had an activation energy of 13 kcal/mole. Three processes were involved in the fluorescence formation. The rate of volatile malonaldehyde generation during lipid oxidation depended on the extent of malonaldehyde formation to the one half power and had an activation energy of 14 kcal/mole. Malonaldehyde sorption on chitosan powder was immediate and independent of temperature. Chitosan fluorescence formation after exposure to volatile malonaldehyde proceeded at a constant rate and had an activation energy of 13 kcal/mole.