Headspace Oxygen Content Research Articles

Revisiting polar paradox: antioxidant activity in bulk oil using selected phenol lipids.

The purpose of this work was to re-evaluate the polar paradox theory (PPT) that explains the relationships between the efficacy of antioxidants, their polarity, and their environments. In this study, ascorbic acid (AA), ascorbyl palmitate (AP), gallic acid (GA), gallyl palmitate (GP), Trolox (TR), α-tocopherol (TO), resveratrol (R), and resveratryl palmitate (RP) were employed to assess conjugated dienoic acid (CDA), the p-anisidine value (p-AV), headspace oxygen content, and hexanal formation in a bulk oil system. TR, TO, R, and RP showed better antioxidant activities in CDA and p-AV and higher headspace oxygen content than AA, AP, GA, and GP. AA showed lower hexanal formation than AP, whereas GP, TO, and RP had better antioxidant activity than their derivatives. These findings suggest that the PPT might be useful to explain the oxidation that occurs at the air-oil interface/association colloids but applying it to other assays might not appropriate.

Sealing solid agar in serum bottles for rapid isolation and long-term preservation of chemoautotrophic ammonia-oxidizing bacteria

Ammonia-oxidizing bacteria (AOB) are ubiquitous on the earth and have broad applications in bioremediation. However, the number of their species with standing in nomenclature and deposited in Microbial Culture Collections still remains low. Moreover, only a few novel species have been reported over the last decades. In this study, we sealed agar in serum bottles to develop a kind of solid agar plate with the oxygen concentration in the headspace maintained at low levels. By using these plates, eight AOB isolates including two novel species were obtained. When AOB cells were grown on the sealed solid agar plates, the time to form visible colonies was largely reduced and the maximum diameter of colonies reached 2 mm, which makes the process of AOB isolation rapid and efficient. Based on five AOB isolates, the headspace oxygen concentration had a significant influence on AOB growth either on solid plate or in liquid culture. Especially, when grown under 21 % O2, the number of colonies formed on solid agar plates was very low and sometimes no visible colony formed. Besides the application on AOB isolation, the sealed solid agar plate was also effective for the enumeration and preservation of AOB cells. When preserved under room temperature for more than ten months, the AOB colonies on the plate could still be recovered. This method provides a feasible way to isolate more novel AOB species from the environment and deposit more species in Microbial Culture Collections.

Physiological oxygen conditions enhance the angiogenic properties of extracellular vesicles from human mesenchymal stem cells

BackgroundFollowing an ischemic injury to the brain, the induction of angiogenesis is critical to neurological recovery. The angiogenic benefits of mesenchymal stem cells (MSCs) have been attributed at least in part to the actions of extracellular vesicles (EVs) that they secrete. EVs are membrane-bound vesicles that contain various angiogenic biomolecules capable of eliciting therapeutic responses and are of relevance in cerebral applications due to their ability to cross the blood–brain barrier (BBB). Though MSCs are commonly cultured under oxygen levels present in injected air, when MSCs are cultured under physiologically relevant oxygen conditions (2–9% O2), they have been found to secrete higher amounts of survival and angiogenic factors. There is a need to determine the effects of MSC-EVs in models of cerebral angiogenesis and whether those from MSCs cultured under physiological oxygen provide greater functional effects.MethodsHuman adipose-derived MSCs were grown in clinically relevant serum-free medium and exposed to either headspace oxygen concentrations of 18.4% O2 (normoxic) or 3% O2 (physioxic). EVs were isolated from MSC cultures by differential ultracentrifugation and characterized by their size, concentration of EV specific markers, and their angiogenic protein content. Their functional angiogenic effects were evaluated in vitro by their induction of cerebral microvascular endothelial cell (CMEC) proliferation, tube formation, and angiogenic and tight junction gene expressions.ResultsCompared to normoxic conditions, culturing MSCs under physioxic conditions increased their expression of angiogenic genes SDF1 and VEGF, and subsequently elevated VEGF-A content in the EV fraction. MSC-EVs demonstrated an ability to induce CMEC angiogenesis by promoting tube formation, with the EV fraction from physioxic cultures having the greatest effect. The physioxic EV fraction further upregulated the expression of CMEC angiogenic genes FGF2, HIF1, VEGF and TGFB1, as well as genes (OCLN and TJP1) involved in BBB maintenance.ConclusionsEVs from physioxic MSC cultures hold promise in the generation of a cell-free therapy to induce angiogenesis. Their positive angiogenic effect on cerebral microvascular endothelial cells demonstrates that they may have utility in treating ischemic cerebral conditions, where the induction of angiogenesis is critical to improving recovery and neurological function.

Impact of atmospheric pressure variations on aerobic biodegradation test.

Biodegradation rate is an important index to evaluate the environmental risk of chemicals, which is usually determined by measuring oxygen consumption through respirometer in a biodegradation test. However, atmospheric pressure variations affect reactor oxygen concentration and oxygen volume recorded by respirometer in biodegradation test, and the parameters of reactor volume and test material amount amplify its effect. Atmospheric pressure variation >1 kPa could introduce >20% underestimation in biodegradation rate when a small amount of test material (0.04-0.2 g per 100 g of inoculum) and high reactor volume (2-4 L) were used according to the international standards. A 5 kPa drop in atmospheric pressure leads to a 6% decrease in headspace oxygen concentration in the reactor, which could subsequently inhibit biodegradation microbials and decrease the biodegradation rate by 30%. Moreover, the biodegradation process (oxygen consumption rate) could be accelerated/delayed several times by atmospheric pressure variations compared to the process without variations when the oxygen consumption rate was <5 mL h-1 in a 0.5 or 1 L reactor and <10 mL h-1 in a 2-L reactor. Mitigating the effects of atmospheric pressure variations on biodegradation test includes lowering the reactor volume, increasing the test material amount and recording atmospheric pressure for further modification.

식물성 유지 및 수중유적형 유화계에서 육두구 종자 에탄올 추출물의 항산화활성 평가

The antioxidant ability of 80% ethanolic extract of nutmeg seed (NM80) was evaluated using in vitro assays and bulk oil and oil-in-water (O/W) emulsion matrices. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging, and oxygen radical antioxidant capacity (ORAC) in vitro assays were used to evaluate the antioxidant ability of the extract. The DPPH radical scavenging activities of 25, 50, 100, and 200 μg/mL NM80 were 12.5, 20.9, 35.1, and 62.8%, respectively, while the ABTS cation radical scavenging activities were 2.7, 6.5, 30.5, and 29.8%, respectively, demonstrating a dose-dependent effect. The ORAC value was significantly higher at an NM80 concentration of 25 μg/mL than the positive control (p&lt;0.05). The conjugated dienoic acid (CDA), ρ-anisidine, and tertiary butyl alcohol values in 90-min-heated corn oil containing 200 ppm of NM80 were significantly reduced by 3.26, 16.94, and 17.34%, respectively, compared to those for the sample without NM80 (p&lt;0.05). However, the headspace oxygen content and CDA value in the O/W emulsion containing 200 ppm of NM80 at 60°C had 6.29 and 82.85% lower values, respectively, than those for the sample without NM80 (p&lt;0.05). The major volatile compounds of NM80 were allyl phenoxyacetate, eugenol acetate, and eugenol. NM80 could be an effective natural antioxidant in lipid-rich foods in bulk oil or O/W emulsion matrix.

The Development of a Novel Headspace O2 Concentration Measurement Sensor for Vials.

In the process of manufacture and transportation, vials are prone to breakage and cracks. Oxygen (O2) in the air entering vials can lead to the deterioration of medicine and a reduction in pesticide effects, threatening the life of patients. Therefore, accurate measurement of the headspace O2 concentration for vials is crucial to ensure pharmaceutical quality. In this invited paper, a novel headspace oxygen concentration measurement (HOCM) sensor for vials was developed based on tunable diode laser absorption spectroscopy (TDLAS). First, a long-optical-path multi-pass cell was designed by optimizing the original system. Moreover, vials with different O2 concentrations (0%, 5%, 10%, 15%, 20%, and 25%) were measured with this optimized system in order to study the relationship between the leakage coefficient and O2 concentration; the root mean square error of the fitting was 0.13. Moreover, the measurement accuracy indicates that the novel HOCM sensor achieved an average percentage error of 1.9%. Sealed vials with different leakage holes (4, 6, 8, and 10 mm) were prepared to investigate the variation in the headspace O2 concentration with time. The results show that the novel HOCM sensor is non-invasive and has a fast response and high accuracy, with prospects in applications for online quality supervision and management of production lines.

Protein photodegradation in the visible range? Insights into protein photooxidation with respect to protein concentration

Visible light (400–800 nm) can lead to photooxidation of protein formulations, which might impair protein integrity. However, the relevant mechanism of photooxidation upon visible light exposure is still unclear for therapeutic proteins, since proteinogenic structures do not absorb light in the visible range. Here, we show that exposure of monoclonal antibody formulations to visible light, lead to the formation of reactive oxygen species (ROS), which subsequently induce specific protein degradations. The formation of ROS and singlet oxygen upon visible light exposure is investigated using electron paramagnetic resonance (EPR) spectroscopy. We describe the initial formation of ROS, most likely after direct reaction of molecular oxygen with a triplet state photosensitizer, generated from intersystem crossing of the excited singlet state. Since these radicals affect the oxygen content in the headspace of the vial, we monitored photooxidation of these mAb formulations. With increasing protein concentrations, we found (i) a decreasing headspace oxygen content in the sample, (ii) a higher relative number of radicals in solution and (iii) a higher protein degradation. Thus, the protein concentration dependence indicates the presence of higher concentration of a currently unknown photosensitizer.

A unifying approach to lipid oxidation in emulsions: Modelling and experimental validation

Lipid oxidation is a longstanding topic within the field of food technology, and is strongly related to loss of product quality and consumer acceptance. Both for bulk oils and emulsions, the chemical phenomena involved in lipid oxidation have been extensively researched, and various reaction pathways have been identified. They are different in bulk oil compared to oil-in-water (O/W) emulsions in which the oil–water interface plays a prominent role. Most probably because of the complexity of the reaction scheme in combination with mass transfer effects, there is no model that describes lipid oxidation in emulsions in a unified fashion, and that is the aim that we have set ourselves to achieve.We use lipid oxidation data previously obtained in O/W emulsions made with 5 different emulsifiers (2 surfactants, and 3 proteins), in well-mixed systems where the oxygen-to-oxidizable lipid ratio is strictly controlled. We use data pertaining to headspace oxygen concentration, and to primary and secondary lipid oxidation products to develop a model based on reaction kinetics, including not only the classical reaction scheme (starting from an unsaturated lipid, LH) but also radical initiation from hydroperoxides, which is thought to be an effect that is overlooked in the classical description of the initiation step.We were able to describe the course of the reactions in these emulsions using the same reaction rate constants for all emulsions, with the exception of the two related to radical-based initiation. In Tween 20- and Tween 80-stabilized emulsions, initiation stems most probably solely from decomposition of hydroperoxides; this implies that lipid oxidation in these emulsions is co-determined by the initial (“pre-existing”) hydroperoxide concentration. In protein-stabilized emulsions, on the other hand, lipid radical initiation is probably linked to reactions involving proteins (co-oxidation reactions), whereas initiation through decomposition of hydroperoxides seems less important, if at all. From this, we can conclude that the difference between both types of emulsions with regard to lipid oxidation mechanisms is related to differences in radical initiation.The developed model can serve as a unified basis for understanding lipid oxidation in emulsions, through which additional effects beyond the bare reaction kinetics, such as mass transfer effects, can be identified and used to e.g., quantify antioxidant effects, which is part of follow-up research.

Proof of concept: predicting the onset of meat spoilage by an integrated oxygen sensor spot in MAP packages

During storage of modified atmosphere packaged (MAP) meat, the initial microbiota grows to high cell numbers, resulting in perceptible spoilage after exceeding a specific threshold level. This study analyses, whether elevated oxygen consumption in the headspace of MA-packages would enable a prediction method for meat spoilage. We monitored the growth of single spoiling species inoculated on high-oxygen MAP beef and poultry, performed sensorial analysis and determined oxygen concentrations of the headspace via a non-invasive sensor spot technology. We detected microbial headspace oxygen consumption occurring prior to perceptible meat spoilage for certain species inoculated on beef steaks. However, headspace oxygen consumption and cell counts at the onset of spoilage were highly species-dependent, which resulted in a strong (Brochothrix thermosphacta) and moderate (Leuconostoc gelidum subspecies) decrease of the headspace oxygen content. No linear decrease of the headspace oxygen could be observed for Carnobacterium divergens and Carnobacterium maltaromaticum inoculated on poultry meat. We demonstrate the applicability of an incorporated oxygen sensor spot technology in MAP meat packages for detection of spoilage in individual packages prior to its perceptible onset. This enables individual package evaluation and sorting within retail, and consequently reduces meat disposal as waste.

High gas barrier properties of whey protein isolate-coated multi-layer film at pilot plant facility and its application to frozen marinated meatloaf packaging

At pilot plant facility, whey protein isolate-coated multi-layer film was manufactured to develop food packaging with high gas barrier properties. The developed film showed a more rigid and stretchable matrix, with about 1.4 times higher mechanical properties than those of the aluminum oxide-deposited multi-layer film, the commercial film. On the other hand, it showed respectively, 2.16 and 2.36 times higher oxygen and water vapor permeability than the commercial film. The developed film was applied to packaging for frozen marinated meatloaf to evaluate the food quality changes, including headspace oxygen concentration, moisture content, and lipid oxidation. The developed films did not induce significant differences in physicochemical properties of the meatloaves and even sensory evaluation after 6 months compared to commercial films, delaying quality changes of meatloaves as effectively as commercial films. Therefore, these results demonstrated that the developed film has great potential as a frozen food packaging material in practical applications.

Effect of perforation packaging on quality of fresh-cut carrot during storage

AbstractThe aim of this work was to evaluate the effect of packaging perforation on quality of carrot slices during cold storage at 5 °C. Polyethylene bags with different number of perforations (3, 4, and 6) were used in this experiment. Headspace oxygen concentration, respiration, weight loss, surface color, firmness, pH, and soluble solid content were examined throughout storage. It was observed, that all the investigated packaging were effective in maintaining the quality of carrot slices compared to the control. There was no symptom of decay until 12 days. In addition, pH, soluble solid content, and firmness showed nonsignificant change. Moreover, weight loss of packed carrot slices was below 2% after 12 days of storage. Packed carrot had better appearance at the end of experiment (12 days) than that of control.

Mathematical approach to lipid oxidation of goat infant formula powder

Oxygen reacts with unsaturated fatty acids from goat milk powder to produce primary oxidation products, which break down further to secondary oxidation products causing off flavours. Milk powder oxidation experiments were conducted under accelerated storage conditions using a range of higher temperatures from 37 °C to 57 °C over a period of 12–24 weeks. The depletion of headspace oxygen concentration and the formation of hexanal concentration were found to be highly correlated (R2 0.91–0.92). The chemical kinetic constants were estimated by fitting a general nth order reaction with an Arrhenius law model with the concentration of oxygen obtained experimentally. The model was used to predict the shelf life of the milk powders under standard storage conditions at 25 °C using the relationship of oxygen consumption to hexanal production and using the results of the sensory trials that gave the limits of hexanal concentration when rancidity was detected.

Influence of ventilation in H2S exposure and emissions from a gravity sewer.

This study was carried out to evaluate the effect of natural ventilation and intermittent pumping events in hydrogen sulfide and methane dynamics, in terms of system operation and risk of gas exposure. Work was conducted in a full scale gravity sewer downstream of pumping stations, in Portugal. Different ventilation rates and locations were assessed, as well as H2S removal rates and potential exposure risk, through the opening of distinct manhole covers. Increased ventilation, resulting from opening of one manhole cover, saw a 38% increase in average pipe air velocity peaks, doubling the estimated rate of air turnovers per day, accompanied by an increase of nearly 20% in H2S average removal rate. Simultaneous opening of two manhole covers induced similar airflow rates through the vent stack, but different rates throughout the pipe. H2S removal rates were also found to differ, according to location of open manholes, but also initial H2S headspace concentration. Under more unfavourable conditions, natural ventilation did not suffice in attaining recommended safety concentrations, regardless of number and location of open manhole covers. H2S concentrations above defined thresholds were verified for all studied setups. Headspace oxygen concentrations below an 18.5% asphyxiation threshold also occasionally occurred, even at manholes immediately downstream of ventilation point.

The effect of trans-polyisoprene/LDPE based active films on oxidative stability in roasted peanuts

A natural trans-polyisoprene (PSN)-based rubber that functions as a light-activated oxygen-scavenging film were developed and applied this material to the packaging of roasted peanuts to prevent loss of quality due to oxidative degradation. Results of the oxygen scavenging analysis indicated that films exhibited reasonable oxygen scavenging rates. Roasted peanuts were packaged with or without LDPE/PSN films, and they were stored for 90 days at 25 °C for oxidative analysis. The roasted peanuts packaged with LDPE/PSN films exhibited significantly lower (P < 0.05) headspace oxygen content within the packages than that of controls containing pure LDPE films. The Hunter L, a, and b values for peanuts packaged with LAE/PSN films were significantly higher (P < 0.05) than those of the control sample. After 90 days of storage, total peroxide, TBA values increased. Total peroxide values increased from 0 to 28.11 meqQ2/Kg in controls and 17.51 ± 0.11 and 15.28 ± 0.01 meqO2 /Kg in peanuts packaged in 10 and 20% PSN LDPE films, respectively, and similar results were observed for TBA values. These results demonstrated that experimentally developed LDPE/PSN oxygen scavenging films inhibited oxygen-mediated deterioration of roasted peanuts. The LDPE/PSN 10 and 20% films may be useful as active food‐packaging material.

TDLAS/WMS Embedded System for Oxygen Concentration Detection of Glass Vials with Variational Mode Decomposition

Whether the oxygen content for medical glass vials can be measured accurately affects greatly the ingredient stability of sterile pharmaceuticals. Tunable diode laser absorption spectroscopy (TDLAS/WMS) based on wavelength modulation has the remarkable advantages of non-contact, low cost, high sensitivity, real-time response, which shows great potential in the field of in-site oxygen concentration detection. Due to the short optical path and various environmental disturbances, it is challenging to measure the headspace oxygen concentration in open-path optical environment. Targeting this challenge, this paper designs a TDLAS/WMS-based gas concentration sensing architecture and turns it into an embedded detection system. Then, a robust signal reconstruction method based on variational mode decomposition (VMD) is established to suppress the random noise of the demodulated harmonic signal. Hence, the oxygen concentration can be reliably inversed from the peak-to-peak values (Vp-p) of the 2nd harmonic signal. This detection framework is abbreviated as WMS+VDM+Vp-p. Encouragingly, the preliminary application on a glass vial encapsulation line demonstrate that the proposed method performs promising results with an absolute detection error of within ±1.5% and a minimal Allan deviation of 0.0010@(100s), which provides a good start for the on-site headspace oxygen concentration measurement for pharmaceutical glass vials.

Headspace Oxygen Concentration Measurement for Pharmaceutical Glass Bottles in Open-Path Optical Environment Using TDLAS/WMS

Accurate measurement of oxygen concentration for pharmaceutical glass bottles is of great significance to ensure the asepsis of medicine and stability of ingredients. With merits of high sensitivity, low cost, noncontact, and real-time response, the wavelength-modulation-based tunable diode laser absorption spectroscopy (TDLAS/WMS) technology shows great potential to achieve in-site oxygen concentration detection by the single-line spectrum measurement. This article focuses on headspace oxygen concentration measurement in the open-path optical environment, which is extremely challenging due to the short light path length and random ambient noises. First, a signal reconstruction method is established based on the discrete wavelet packet transform (DWPT), where random noise suppression is implicitly achieved. Then, oxygen concentration is inversed among the data between two adjacent valley values of the demodulated second-harmonic signal by multiple linear regression (MLR), and the linear discriminant analysis (LDA) is imported to enhance the information sparsity of second-harmonic signal matrix and to address the multicollinearity problem. Simulation results prove that our proposed method achieved considerable detection accuracy with the average absolute error of 0.05%. This article also designed a TDLAS/WMS prototype, and the experimental results aiming at glass bottles with different oxygen concentration of 0%, 5%, 10%, and 21% in open-path optical environment indicate our method has achieved an encouraging average absolute error of 0.54% and can survive well when the normalized signal-to-noise ratio (SNR) is within 0.85–1. These results promise that the proposed methodology can be widely applied in in-site automatic optic inspection (AOI) instrumentation of headspace oxygen concentration measurement for glass vials.

Extraction of γ-oryzanol from rice bran using diverse edible oils: enhancement in oxidative stability of oils.

Diverse edible oils including perilla, corn, soybean, canola, sunflower, olive, and grape seed oils were mixed with heat-stabilized rice bran to extract γ-oryzanol from the rice bran. The oxidative stabilities of the oils with or without extraction were compared by analyzing the headspace oxygen content, conjugated dienoic acid (CDA) values, and p-anisidine values (p-AV). Grape seed oil extracted significantly high γ-oryzanol content while canola oil extracted lowest γ-oryzanol content (p < 0.05). All the solvent oils except corn oil possessed enhanced oxidative stability at 100°C after extracting γ-oryzanol from stabilized rice bran, based on the results of the headspace oxygen depletion and CDA methods. However, all the recovered oils had high p-AV than vegetable oils. Especially, perilla oil had an exceptionally high p-AV, which may be due to its high linolenic acid content.

Lignin-Based Biopolymeric Active Packaging System for Oil Products.

Antioxidant activity of enzymatically modified soybean protein film with two different forms of added lignin (alkali lignin and lignosulfonate) was investigated using two stimulated food systems involving direct and indirect contact with soybean oil and fish fatty acid ethyl ester (FAEE). For the direct system, control and lignin-doped films were added to oil vials which were stored at dark under 40 °C whereas for indirect, films were used to cover oil-containing glass vials stored under standard commercial lighting conditions. Autoxidation of oil samples in the direct contact system was determined by peroxide value (PV), color, headspace oxygen, and volatile compounds, while for the indirect contact system photoxidation was determined by using PV and color. For the direct contact system with soybean oil, the PV was significantly lower during storage for both lignins used compared to the control (packaging system without lignin film). There was not a significant effect of lignin on the color of the oils (P > 0.05). Modified films tested in this study did not have a significant effect on headspace oxygen contents of oil samples; however, it resulted in reduced volatile compounds for both soybean oil and fish oil samples. Based on our observation, soybean protein films with lignin showed a greater impact on soybean oil than fish oil, possibly because of high initial oxidation levels in the fish oil. Enzymatic modified soy protein films with lignin are alternative active packaging materials for highly sensitive to oxidation by radical and UV light. PRACTICAL APPLICATION: Plastic packaging materials require the use of petroleum oil and are not biodegradable. Packaging materials made from renewable, biodegradable biopolymers are of great interest but often suffer from performance problems, such as weak mechanical properties compared to petroleum-based plastics. Applying modified biopolymeric film with lignin in the inner layer of food packaging system improved some aspects of their performance during storage, not only by preventing the migration of chemical compounds from the package to the food but also by radical scavenging activity and UV-blocking ability of the packaging system.

Lecithin Near Its Critical Micelle Concentration Increases Oxidative Stability of Non‐Stripped Corn Oil But Not Stripped Corn Oil

Effects of lecithin (HLB 4.5) on oxidative stability of non‐stripped or stripped corn oil are determined during storage at 50 °C. Headspace oxygen content of non‐stripped corn oil containing lecithin decreased less with the increasing concentration of lecithin (300–3000 ppm). Lecithin‐supplemented non‐stripped corn oil near and above critical micelle concentration (CMC, 1288 ppm) had higher oxidative stability as compared to other samples according to conjugated dienoic acid and p‐anisidine value assays. Antioxidant and tocopherol concentrations in non‐stripped corn oil samples containing lecithin near CMC are found to be the highest. Stripped corn oil has CMC of 1790 ppm lecithin and 600 ppm lecithin shows higher antioxidant properties than other concentration of lecithin from 1200 to 3000 ppm. Presence of phospholipids affected oxidative stability of bulk oils. Non‐stripped corn oil supplemented with lecithin near CMC shows the highest oxidative stability, which could be due to the incorporation of tocopherols into the association colloids formed by the added lecithin.Practical Application: Controlling rate of lipid oxidation in bulk oils is one of the important topics in lipid science. Addition of commercially available lecithin (HLB 4.5) could enhance the oxidative stability in non‐stripped corn oil especially, at the concentration of lecithin near CMC. Presence of phospholipids affected oxidative stability of bulk oils. By using knowledge shown in this study, food industries could save costs by optimizing the lecithin concentration in bulk oils, which could be used as ingredients of many processed foods.Addition of commercially available lecithin enhances oxidative stability in non‐stripped corn oil. Lecithin near or over its critical micelle concentration shows higher antioxidant activity in non‐stripped oil compared to other concentrations of lecithin. Added lecithin increases tocopherol stability, especially α‐tocopherol in non‐stripped bulk oil during storage. For stripped corn oil, 600 ppm lecithin only shows some antioxidant power and other concentrations do not enhance oxidative stability.

Development of a Sulfite-Based Oxygen Scavenger and its Application in Kimchi Packaging to Prevent Oxygen-mediated Deterioration of Kimchi Quality.

A sulfite-based oxygen scavenger (SOS) was developed with sodium metabisulfite and applied to kimchi packaging in an attempt to prevent oxygen-mediated kimchi quality degradation. The results of the oxygen- scavenging capacity test showed that the SOS had a competitive oxygen- scavenging performance in comparison with commercial oxygen scavengers. The kimchi was packaged with and without the SOS and stored over 12 weeks at 0 and 10 °C for an SOS application test. The kimchi treated with the SOS showed a significantly lower (P < 0.05) headspace oxygen and carbon dioxide concentration and pressure inside the packages than the control. The pH and titratable acidity values indicated that the SOS did not retard the kimchi fermentation process. The Hunter L, a, and b values in the kimchi packaged with the SOS were significantly higher (P < 0.05) than those in the control. After 12 weeks of storage, the total aerobic bacteria counts were reduced by 1.32 and 2.97 log CFU/g, lactic acid bacteria counts were reduced by 2.22 and 4.42 log CFU/g, and total yeasts and molds counts were reduced by 1.76 and 3.04 log CFU/g at 0 and 10 °C, respectively, by the SOS compared to those in the control. These results demonstrated that the developed SOS inhibited oxygen-mediated deterioration of the kimchi, but did not affect the kimchi fermentation. Therefore, our SOS can be used as an active food-packaging technology for kimchi quality preservation. PRACTICAL APPLICATION: A newly designed sulfite-based oxygen scavenger was applied in kimchi packaging, and it showed remarkable preventive effects on the kimchi quality deterioration caused by oxygen. Accordingly, it can be used as an active food-packaging technology to maintain kimchi quality during the storage period. Moreover, it can also be effectively utilized in the packaging of other high-moisture foods such as meat, fish, fruits, vegetables, and dairy products.