Oxidation Volatile Compounds Research Articles

“Milk on Ice”: A detailed analysis of Ernest Shackleton's century-old whole milk powder in comparison with modern counterparts

Whole milk powder (WMP) manufactured in New Zealand in 1907 was sent to the Antarctic continent with the Shackleton-led British Antarctic Expedition from 1907 to 1909. This powder was stored at ambient conditions at Shackleton's Hut at Cape Royds, Antarctica, for over 100 yr before a sample was collected on behalf of Fonterra by the Antarctic Heritage Trust. Having spent most of its existence both dried and in frozen storage, any deleterious reactions within the WMP would have been markedly retarded. The composition and some properties of the roller-dried Shackleton's WMP are reported along with those of 2 modern spray-dried New Zealand WMP. The Shackleton powder was less white and more yellow than the modern WMP and was composed of flakes rather than agglomerated particles, consistent with that expected of a roller-dried powder. Headspace analysis showed lipolytic and oxidative volatile compounds were present in the Shackleton WMP, indicting some deterioration of the milk either before powder manufacture or on storage of the finished product. On a moisture-free basis, the Shackleton WMP had higher protein, higher fat (with a markedly higher free fat level), higher ash, and a lower lactose level than the modern WMP. The lysine level was lower in the Shackleton WMP compared with the spray-dried powders, whereas the fatty acid composition was relatively similar. The sodium level was markedly higher in the Shackleton WMP compared with the spray-dried powder, which is probably due to the addition of an alkaline sodium salt to adjust the pH of the milk before roller drying. Lead, iron, and tin levels were markedly higher in the Shackleton WMP compared with the spray-dried powders, possibly due to the equipment used in powder manufacture and the tin-plated cases used for storage. The proteins in the Shackleton WMP were more lactosylated than in the spray-dried powders. The Shackleton WMP had a higher ratio of κ-casein A to B variants and a higher ratio of β-lactoglobulin B to A variants than the spray-dried powders, whereas the αS1-casein, β-casein, αS2-casein, and α-lactalbumin protein variants were similar in all powders. The total phospholipid content was markedly lower in the Shackleton WMP than the spray-dried powders, primarily due to a lower phosphatidylethanolamine concentration. The molecular species distributions within the phospholipid classes were generally similar in the 3 powders. Claims are sometimes encountered that the milk of today is different from that consumed by previous generations. However, this comparative study has shown that the Shackleton WMP was generally similar to modern WMP. Although differences in some components and properties were observed, these were attributable to the manufacturing equipment and processes used in the pioneering years of WMP manufacture.

Antioxidant-efficient indicator determinate by the relationship between β-myrcene/caryophyllene (α, β) on Hop (Humulus lupulus) essential oils under an accelerated oxidation test

The hop essential oil (Humulus lupulus) can be used as a natural additive in food to prevent lipid oxidation, replacing synthetic ones. The aim was to study the antioxidant activity of hop essential oil under accelerated oxidation conditions and determine the relationship between β-myrcene/caryophyllene (α, β) (M/Cs) as an antioxidant-efficient indicator. Sunflower oil was used as a lipid model. Five treatments were carried out (control, BHT, Chinook (CH), Cryo Citra (CYT), and Falconers Flight (F) at 0.02 %). The antioxidant efficacy was measured through free radical-scavenging activity, peroxide value, conjugated dienes, and oxidation volatile compounds. Cryo Citra essential oil showed the highest antioxidant activity, comparable with BHT, and M/Cs of 3.14 and F (0.91) and CH (0.57) showed good performance in the accelerated oxidation test while Chinook showed the best free radical-scavenging activity. The M/Cs relationship can be used as an antioxidant-efficient indicator with values biggest than 0.90.

Capsaicin Rich Low-Fat Salad Dressing: Improvement of Rheological and Sensory Properties and Emulsion and Oxidative Stability

This study aimed to investigate the potential use of cold-pressed hot pepper seed oil by-product (HPOB) in a low-fat salad dressing to improve its rheological properties, emulsion, and oxidative stability. The total phenolic content (TPC), the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and CUPRIC reducing antioxidant capacity (CUPRAC) values were 317.4 mg GAE/100 g, 81.87%, and 6952.8 mg Trolox/100 g, respectively. The capsaicin, dihydrocapsaicin, and total carotenoid content were 175.8 mg/100 g, 71.01 mg/100 g, and 106.3 µg/g, respectively. All emulsions indicated shear-thinning, viscoelastic solid-like behavior, and recoverable characteristics, which were improved via enrichment with HPOB. The thermal loop test showed that the low-fat sample formulated with 3% HPOB indicated little change in the G* value, showing that it exhibited high emulsion stability. The induction period values (IP) of the salad dressing samples containing HPOB (between 6.33 h and 8.33 h) were higher than the IP values of the control samples (3.20 h and 2.58 h). The enrichment with HPOB retarded the formation of oxidative volatile compounds of hexanal, nonanal, and 1-octene-3-ol. According to the results presented in this study, HPOB could be effectively used in a low-fat salad dressing to enhance its rheological characteristics and oxidative stability.

Evaluation of Hemp Seed Oils Stability under Accelerated Storage Test.

The interest in hemp seed oil has recently increased, due to the latest regulations which allow its use as food. Hemp seed oil is characterized by a high content of polyunsaturated fatty acids, which are highly prone to oxidation. Accelerated thermal oxidation (60 °C, 18 days) has been applied to nine types of cold-pressed hemp seed oils to monitor the evolution of the samples during oxidative deterioration. The results showed that the only determinations of primary (peroxide value) and secondary (TBARs) oxidation products did not allow a sufficient or correct evaluation of the oxidative changes of hemp seed oils during storage. In fact, samples at the end of the test were primarily characterized by a high presence of oxidation volatile compounds and a significant decrease of antioxidants. Several volatiles identified before the accelerated storage, such as the predominant α-pinene and β-pinene, gradually decreased during the accelerated storage period. On the other hand, aldehydes (hexanal, (E)-2-hexenal, heptanal, (E,E)-2,4-hexadienal, (E)-2-heptenal, (E,E)-2,4-heptadienal, (E,Z)-2,4-heptadienal, 2-octenal, nonanal, nonenal, 2,4-nonadienal, (E,E)- 2,4-decadienal and 2,4-decadienal), ketones (1-octen-3-one, 3-octen-2-one, (E,E)-3,5-octadien-2- one and 3,5-octadien-2-one), acids (propionic acid, pentanoic acid, hexanoic acid and heptanoic acid) and 2-pentyl-furan increased during the accelerated storage, as principal markers of oxidation.

Nutritional quality of Ready-to-Use Therapeutic Foods: focus on lipid composition and vitamin content

Severe Acute Malnutrition (SAM) is still a public health issue in many low-income and middle-income countries. Its management has changed with the development of Ready-to-Use Therapeutic Foods (RUTF) that are energy-dense, lipid-based, micronutrient-enriched foods. The purpose of the present study was to define some aspects of the nutritional profile (in particular, lipid content, fatty acids profile, lipophilic vitamin content), oxidative status, and mycotoxin content of three RUTF products (of which two manufactured in Asia and one in Europe), at different time points during their storage. All RUTF displayed good lipid stability, with peroxide values < 10 meqO2/kg lipids, acidity index < 0.6 g/100 g lipids, and very low amounts of secondary oxidation volatile compounds. Only the one produced in Europe complied with the international recommendations on vitamin A and E contents. Lipid content ranged from 28.7 ± 0.5 to 41.2 ± 2.4 g/100 g. Oleic acid, palmitic acid, and linoleic acid (47.2 ± 7.4%, 26.8 ± 2.1%, and 12.4 ± 3.9% of total lipids, respectively) were the main fatty acids. Only one of the samples made in Asia exceeded the regulatory limit of mycotoxins. The RUTF lipid phase was rather stable at ambient temperature from 9 to 12 months, and appropriate packaging may have contributed to a major stability.

The effect of blueberry pomace on the oxidative stability and cooking properties of pork patties during chilled storage

The aim was to evaluate the effect of blueberry pomace (BBP) on the oxidative stability and cooking properties of pork patties (PPs) during chilled storage. PPs were prepared into four groups: control, control with the addition of 0.3% ascorbic acid, with 1% BBP, and with 2% BBP. Three PPs were prepared for each batch and analyzed raw after 1, 3, and 7 days of refrigerated storage, respectively. Another three PPs were cooked and sampled for each batch at the same sampling times. An HPLC-HRMS method and SPME GC-MS techniques were developed to identify and quantify the main polyphenols present in the BBP and the lipid oxidation compounds generated in cooked PPs, respectively. The application of the BBP to PPs resulted in desirable changes in the cooking characteristics of the products. BBP is also able to significantly reduce oxidation volatile compounds concentration with the consequent delay of lipid oxidation. Practical applications Blueberries have a high polyphenol content and, for commercial purposes, a large quantity of this fruit is transformed into juices, and waste products that are generally discarded are produced. Addition of blueberry pomace (BBP) possessing high antioxidant activity can provide a good way of reducing the rate of oxidation changes in the in ground meat products during storage. Recent research has promoted the use of berry pomace for animal feeding purpose and for the development of novel functional food ingredients. The use of BBP as additives provides some beneficial health effects to meat consumers with a reduction of waste products. The present study demonstrates that the application of the BBP as a food additive to pork patties resulted in desirable changes in the cooking characteristics of the products due to an increase in the water retention capacity of the matrix.

Oxidative stability and physical properties of mayonnaise fortified with zein electrosprayed capsules loaded with fish oil

This study investigated the oxidative stability and physical properties of low-fat mayonnaise fortified with electrosprayed zein capsules loaded with fish oil. A high encapsulation efficiency (EE) (83 ± 1%) was achieved in the encapsulates and semi-spherical capsules with rough surface and mean diameter of 2.4 ± 0.7 μm were obtained. The amount of primary oxidation products of the zein capsules did not increase over the storage, even though the initial content was higher compared to neat fish oil. Cryo-SEM images revealed that the capsules remained intact when they were incorporated into a water-based food matrix like mayonnaise. This explained the lower content of hydroperoxides at the end of the storage for the capsule-enriched mayonnaise (Mayo-C) when compared to mayonnaise enriched with neat fish oil (Mayo-F) (2 meq/kg oil vs. 6 meq/kg oil, respectively). Even though, volatile compounds from the secondary oxidation of omega-3, such as 2-ethylfuran and 1-penten-3-one were found in higher amounts in Mayo-F, a higher overall increase in all other secondary oxidation products was observed in Mayo-C. This increase was attributed to the formation of oxidation volatile compounds from the zein material, together with the oxidation of un-encapsulated fish oil droplets. Moreover, Mayo-C presented higher viscosity and droplet size than Mayo-F, which also increased during storage, although no further alterations of the emulsion like creaming were observed. Overall, these findings indicate the benefits of using zein as hydrophobic shell material for the development of omega-3 loaded-electrosprayed capsules intended to the enrichment of water-based food matrices when compared to the use of hydrophilic wall materials.

Comprehensive profiling of lipid oxidation volatile compounds during storage of mayonnaise.

Lipid oxidation is a primary cause of quality deterioration in mayonnaise that leads to a decrease in the nutritional and sensorial value. The evolution of volatile oxidation compounds in sunflower oil mayonnaise stored at varying temperatures for 92days and the antioxidative effect of butylated hydroxyanisole were investigated by static headspace extraction and separation by two dimensional gas chromatography/time-of-flight mass spectrometry. Considerable differences in the headspace composition of samples stored at 4, 25 and 38°C were found due to the different oxidation levels reached. The content of hexanal in mayonnaise at 1-5days of storage at 38°C could be used to predict the corresponding compound in mayonnaise at 1-62days of storage at 25°C. The 10 most important discriminating volatile compounds during lipid oxidation of mayonnaise (at 38°C for 92days) are 3-hexenal, pentanal, 2-heptenal, 2-ethylfuran, hexanal, benzeneacetaldehyde, 2-pentylfuran, 3-methylhexane, 1-pentanol and 2,4-heptadienal. More than half of these compounds have a close relationship with the initial content of linoleic acid that agrees with the fatty acid profile of sunflower oil (~ 70% linoleic acid). These volatiles could be used as additional markers of oxidation in sunflower oil mayonnaise.

Does vitamin fortification affect light oxidation in fluid skim milk?

Off-flavors in milk related to light oxidation form due to photoxidation of native riboflavin and tetrapyrroles, resulting in an array of lipid oxidation compounds. Recent work has established that fortification with water-dispersible vitamin A can result in off-flavors in fluid skim milk caused by vitamin A degradation products in the vitamin premix. The objective of this study was to determine the role of vitamin fortification on light oxidation of high temperature, short time pasteurized fluid skim milk. First, the aroma profiles and aroma-active volatile compounds in light-exposed vitamin premixes were determined by exposing the premixes to fluorescent (FL) or light-emitting diode (LED) light at 2,000 lx at 4°C for 0, 2, 4, 8, or 24 h. A trained panel (n = 6) documented aroma profiles of each vitamin premix at each time point. Headspace solid-phase microextraction followed by gas chromatography-olfactometry and gas chromatography-mass spectrometry (GC-MS) were performed to characterize aroma-active compounds in light-exposed vitamin premixes. In the second experiment, commercial vitamin premixes (vitamin A and vitamin D in oil and water matrices) were used to fortify skim milk (vitamin A: 3,000 IU/946 mL; vitamin D: 600 IU/946 mL). Skim milk was pasteurized, homogenized, and packaged in 946-mL high-density polyethylene jugs. Milks were exposed to FL or LED light at 2,000 lx at 4°C for 4, 12, 24, or 48 h. Controls with and without vitamins and light shielding were included. Riboflavin and vitamin A and D degradation were quantified via ultra-high-performance liquid chromatography. A trained panel (n = 8) documented sensory profiles of milks at each time point. Lipid oxidation volatile compounds were quantified via solid-phase microextraction with GC-MS. Vitamin degradation volatile compounds were quantified via solvent-assisted sorptive stir bar extraction with GC-MS. Riboflavin, vitamin A, and vitamin D degradation were consistent with that reported in previous studies. We found no effect of vitamin fortification on development of typical light oxidation-related off-flavors (cardboard and mushroom) or lipid oxidation-related volatiles (hexanal and heptanal). A perfumey/floral flavor was documented in the oil-based vitamin A-fortified milk, suggesting that light exposure affected the off-flavors contributed by water- versus oil-based vitamin fortification. These results show no evidence that vitamin fortification at current levels provides any protection against light oxidation-related off-flavors in fluid milk.

Odour Detection Threshold Determination of Volatile Compounds in Topical Skin Formulations

Several studies have shown that lipid oxidation can occur in topical skin formulations, but the impact of the individual volatile compounds on off‐odour has not yet been determined. In this study, lipid oxidation is investigated in prototype skin care formulations. Firstly, lipid oxidation volatile compounds that increased in concentration during storage are identified. The results show that the concentration of six volatile compounds increased above previously reported odour detection threshold values in water. These volatile compounds are selected for odour detection threshold value determination and also odour description by a trained sensory panel. In one case, the odour detection threshold value is 50 times higher (less detectable) in skin care products than in water, whereas for other volatile compounds the odour detection threshold value is only 1.5 times higher. The odour description of the volatile compounds is, in most cases, different from that reported in literature. The observed differences are hypothesised to be due to a masking effect of the base odour of the skin care product(s), a volatile‐retaining power of the base matrix and to a cocktail effect of the combined odours from different volatile oxidation products.Practical Application: In this study, the impact of volatile compounds on off‐odour is explored in prototype skin care formulations. The odour detection threshold value and odour description are determined for butanal, pentanal, 3‐methyl‐1‐butanol, 2‐ethyl furan, 2‐pentyl furan and 1‐heptanol in prototype skin care formulations.Overview of the different odour descriptors of the same volatile (3‐methyl‐1‐butanol) when found in topical skin formulations with different lipid contents.

Influence of different flours and starches on gluten-free bread aroma.

The aim of this research was to study the effect of different gluten-free flours (yellow and white corn, rice, oat, teff, buckwheat, amaranth and quinoa) and starches (wheat, corn and potato) on the generation of volatile compounds in the fermented doughs and crumbs. Volatile compounds were analyzed by static headspace-gas chromatography/mass spectrometry (SHS-GC/MS). Nine fermentation and lipid oxidation volatile compounds were evaluated, which were found to be the same from dough to crumb but vary in levels. Concentrations of compounds produced during fermentation were higher in doughs whereas those from lipid oxidation were higher in crumbs. The type of flour/starch affected the concentration of these volatile compounds. The proportions of ethanol and 2/3-methylbutanol (fermentation compounds) were higher in dough from yellow and white corn, rice and oat while the proportions of hexanal, 1-pentanol and 2,4-decadienal (lipid oxidation compounds) were higher in the doughs made with starches. The proportions of ethanol and 2/3-methylbutanol were higher in quinoa and amaranth crumbs whilst hexanal, 1-pentanol and 2,4-decadienal were higher in yellow and white corn crumbs.

Effect of beef finishing diet and retail display on oxidative volatile compounds and their relationship with beef color

Consumer palatability scores, sensory descriptive attributes, and volatile compounds were assessed for beef Longissimus lumborum steaks of USDA Prime, Low Choice, and Standard grades. Overall and flavor liking was greater (P < 0.05) for Prime and Low Choice. Initial flavor impact and fat-like attributes were greater (P < 0.05) among Prime and Low Choice. Prime had greater (P < 0.05) brown/roasted, beef identity, overall sweetness, and umami. Cardboard was greater (P < 0.05) in Standard. Volatile compounds representing flavor development pathways were varied with quality grade. Standard had greater (P < 0.05) abundances of n-aldehydes. Phenylacetaldehyde was greater (P < 0.05) in Prime and Low Choice. Both 2,3-butanedione and 3-hydroxy-2-butanone were greatest (P < 0.05) in Prime. Overall liking was positively correlated with many descriptive attributes, 3-hydroxy-2-butanone, and phenylacetaldehyde, and negatively correlated with cardboard, green, and n-aldehydes. While the measured attributes and volatiles may not be causative of flavor, this data indicates potential for prediction of flavor through their measurement.

Effect of Fresh Garlic on Lipid Oxidation and Microbiological Changes of Pork Patties during Refrigerated Storage.

The effects of two levels (1.4 vs 2.8%) of fresh garlic on lipid oxidation and microbial growth in pork patties were evaluated. Hunter color (L, a, b), pH, thiobarbituric acid reactive substances (TBARS), oxidative volatile compounds, total bacteria and Enterobacteriaceae in the pork patties with or without fresh garlic were measured during storage at 4℃. Addition of fresh garlic decreased redness (a), while increased pH and yellowness (b) values of the fresh pork patties were observed, regardless of the levels added. The TBARS values of the pork patties were increased with the addition of fresh garlic (p<0.05). Similar results were observed in oxidative volatile compounds. A total of 13 volatile compounds were detected in the patties (5 sulfur-containing compounds, including allyl mercaptan, allyl methyl sulfide, diallyl sulfide, methyl-(E)-propenyl-disulfide, and diallyl disulfide, and the 8 other oxidative compounds, including 1-pentanol, hexanal, 1-hexanol, heptanal, (E)-2-heptenal, 1-octen-3-ol, (E)-2-octenal and nonanal). Fresh garlic accelerated development of oxidative products in the pork patties, especially hexanal and the total oxidative volatile compounds. However, the addition of 1.4 and 2.8% of fresh garlic inhibited the growth of total bacteria and Enterobacteriaceae, indicating low total bacterial counts and Enterobacteriaceae than the controls.

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.

Impact of ultrasound treatment on lipid oxidation of Cheddar cheese whey

Ultrasound (US) has been suggested for many whey processing applications. This study examined the effects of ultrasound treatment on the oxidation of lipids in Cheddar cheese whey. Freshly pasteurized whey (0.86L) was ultrasonicated in a contained environment at the same range of frequencies and energies for 10 and 30min at 37°C. The US reactor used was characterized by measuring the generation of free radicals in deionized water at different frequencies (20–2000kHz) and specific energies (8.0–390kJ/kg). Polar lipid (PL), free and bound fatty acids and lipid oxidation derived compounds were identified and quantified before and after US processing using high performance liquid chromatography equipped with an evaporative light scattering detector (HPLC–ELSD), methylation followed by gas chromatography flame ionized detector (GC-FID) and solid phase micro-extraction gas chromatography mass spectrometry (SPME-GCMS), respectively. The highest concentration of hydroxyl radical formation in the sonicated whey was found between 400 and 1000kHz. There were no changes in phospholipid composition after US processing at 20, 400, 1000 and 2000kHz compared to non-sonicated samples. Lipid oxidation volatile compounds were detected in both non-sonicated and sonicated whey. Lipid oxidation was not promoted at any tested frequency or specific energy. Free fatty acid concentration was not affected by US treatment per se. Results revealed that US can be utilized in whey processing applications with no negative impact on whey lipid chemistry.

Ultrasonication and Edible Coating Effects on Lipid Oxidation of Roasted Peanuts

Lipid oxidation is an important factor affecting the quality of roasted peanuts. Coatings applied to the peanuts can enhance oxygen barriers to reduce rancidity. Ultrasonication was used to remove lipids from the peanuts prior to applying the coating to improve attachment of the coating on the peanut surface. Peanuts were roasted at 178°C for 15 min and then sonicated in hexane for 10 min. Whey protein isolate (WPI) 11%, corn protein (Zein) 15%, and carboxymethyl cellulose (CMC) 0.5% were used as coating materials. Sample treatments were: (1) roasted–coated with CMC (RCMC), WPI (RWPI), and Zein (RZEIN); (2) roasted–sonicated–coated with CMC (SCMC), WPI (SWPI), and Zein (SZEIN); (3) roasted–uncoated (R) as a control. Oxidative stability was investigated by gas chromatography–mass spectrometry (GC–MS) to detect formation of volatile compounds. The GC–MS indicated an eightfold, fivefold, and fourfold increase in hexanal formation in R, RZEIN, and SZEIN samples, respectively. But there was 80%, 91%, 18%, and 66% decrease in hexanal formation in RCMC, SCMC, RWPI, and SWPI samples, respectively, as compared to R. Sonication increased capability of coatings to delay hexanal formation by 11% and 48% for CMC and WPI, respectively, as compared to nonsonicated samples. Thus, the coating in combination with ultrasonication treatment was an effective method in delaying formation of oxidative volatile compounds and hence inhibiting rancidity of roasted peanuts.

Volatile profile of heated soybean oil treated with quercetin and chlorogenic acid

Changes in the profile of volatile compounds after the heating of refined soybean oil without adding antioxidants, and treated with quercetin and chlorogenic acid (5-CQA) were investigated by GC/FID, GC/MS, and GC/SNIFFING. The heating temperature of the oil sample was 20 °C for the first minute, and then it was increased up to 160 °C at the rate of 10 °C min-1. The final temperature was kept for 10 minutes. 19 volatiles were identified in the heated samples without antioxidants. Medium-chain carbonyls predominated in the volatile fraction, mainly 2-heptenal, 2,4-heptadienal and 2,4-decadienal. Around 11 to 15 volatile compounds were detected in the heated samples treated with 5-CQA and quercetin, respectively. 5-CQA was not very efficient in delaying the formation of oxidative volatile compounds. The samples quercetin presented lower proportion of carbonyls with C6-C9.. The GC peak area data were used as an approach to estimate the relative content of each volatile compound and indicate that the samples treated with quercetin (p < 0.05) had significantly lower values for, 1-pentanol, 2,4-heptadienal, and 2,4-decadienal compared with those without antioxidants and treated with 5-CQA. GC/SNIFFING analysis revealed a smaller odor perception in the samples treated with 5-CQA compared to those without antioxidants. No odor was perceived in the heated samples treated with quercetin. These results indicate greater effectiveness of quercetin in delaying the formation of oxidative volatile compounds in soybean oils subjected to mild heating conditions. Apparently, biopolyphenols used in the present work showed good oxidative stability since no new volatile compound was detected in the heated samples treated with them.

Effect of storage and packaging on fatty acid composition and oxidation in dry fermented sausages made with added olive oil and antioxidants

Dry fermented sausages produced by a partial substitution of pork backfat with pre-emulsified olive oil were manufactured and stored (2 and 5 months) using different packaging conditions (aerobic/vacuum piece/vacuum slices) in order to evaluate the intensity of the oxidation process. Also the effect of the addition of butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA) to one of the modified batches was studied. Addition of olive oil, especially with antioxidants, was more effective than using vacuum storing methods in avoiding lipid oxidation during storage. After 5 months of storage at 4 °C, the combination of the increase in oleic acid and the preservation of PUFA by the antioxidant activity of the olive oil emulsion and antioxidants (when added), lead to better MUFA + PUFA/SFA ratios in olive oil containing sausages (1.90–1.98 g/100 g fatty acids) and particularly in antioxidants containing sausages (2.02–2.16 g/100 g) than in control ones (1.72 g/100 g). Vacuum packaging of the piece was the best method to minimise formation of lipid oxidation volatile compounds.