Low Oxygen Storage Research Articles

The Effects of Oxygen Availability in the Seed Container during Storage on Seed Germination in Tomato, Onion, Cabbage, and Marrow Seeds

This research was conducted to test the effect of oxygen content (low O2, high O2, air) during hermetic seed storage at 20±2°C over 8 and 12 months on seed germination and seedling root and shoot length in tomato, onion, cabbage, and marrow seeds. Samples with low oxygen storage had higher seed germination as well as longer root and shoot lengths than both control and high oxygen storage. When the storage period extended from 8 to 12 months, the germination percentages also reduced. However, these results varied among the species. The greatest advantage of low oxygen storage was obtained in tomatoes, which exhibited 15% and 9% higher germination compared to the control after 8 and 12 months of storage, respectively. The longest root and shoot lengths of 6.4 cm and 11.6 cm, respectively, were obtained from the low oxygen storage treatments. A similar positive effect of low oxygen storage was observed in onion and cabbage seeds but not in marrows. Results indicated that oxygen level in the packets during storage can be an effective component to maintain high seed germination and seedling growth potential (seed vigour). The difference in the effect on different species is a matter of further research.

Low oxygen storage alleviates chilling injury in cherry tomatoes

Low oxygen storage alleviates chilling injury in cherry tomatoes

Low oxygen storage impacts on blueberry fruit quality

Low oxygen storage impacts on blueberry fruit quality

Impact of low oxygen storage on post-storage quality of pasteurized walnut (Juglans regia L.) kernels

Walnut (Juglans regia) kernels were obtained from two facilities, each using a different method for pasteurization to achieve a log 4 and log 5 reduction in the bacterial load on the kernel surface. Continuous pasteurization utilized high temperature steam applied for a short period, and batch pasteurization utilized lower temperature steam applied in a pressurized chamber for a longer period. Log 4 and 5 walnut kernels from both treatment methods were stored at 20 °C in air or sealed in bags with a low oxygen transmission rate, and an oxygen absorbing sachet was inserted to reduce internal oxygen concentrations to < 0.5 %. After pasteurization and packaging, walnuts were stored and evaluated periodically for peroxide value, hexanal, free-fatty acids, and total tocopherols. These objective quality measures were compared to descriptive sensory analyses of walnut taste, texture, and aroma conducted by a trained sensory panel. Continuous pasteurization of walnuts increased the rate of oil oxidation and loss of total tocopherols, but storage of walnuts in low oxygen atmospheres mitigated some of the negative quality impacts. Continuous pasteurization resulted in an immediate decreased in total tocopherols prior to storage under low oxygen atmospheres; however, low oxygen storage reduced subsequent losses in tocopherols. Batch pasteurization did not enhance quality degradation as compared to unpasteurized controls, but storage under low oxygen reduced oil oxidation and slowed the degradation of total tocopherols, as typically observed during walnut storage.

The Impact of Fruit Ripeness on the Lower Oxygen Limit, Chlorophyll Fluorescence and Fermentation Behavior in Apples

Dynamic Controlled Atmosphere-Chlorophyll Fluorescence storage (DCA-CF) uses a fluorescence-based measurement method to detect fermentation in apples (Malus × domestica BORKH.) caused by low-oxygen levels at an early stage. In recent years, it has been observed that individual apples of the same variety and origin can exhibit different fermentation behavior when stored under completely identical conditions. The causes of the different fermentation behavior must be found in order to be able to use DCA storage optimally. This study aimed to find the causes of the different fermentation behaviors of individual apples. Our results show that fruit ripeness can affect the lower oxygen limit (LOL), especially immediately after harvest, when the starch degradation in the fruit is not yet complete. A significant increase in the LOL was observed in ‘Elstar’ (2020: 0.3 kPa, 0.6 kPa, 0.9 kPa; 2021: 0.3 kPa, 0.4 kPa, 0.6 kPa). ‘Braeburn’ also exhibited this behavior regarding the LOL at a lower level. The LOL could not be identified for some of the fruit (varying from 12.5% to 41.7% of the examined apples) previously stored in Ultra Low Oxygen (ULO) storage for 4 months. Also, the chlorophyll content in the apple skin influences the fluorescence measurement method. Within 2 weeks, the chlorophyll content in the apple skin was halved. If the chlorophyll content drops, the reliability of the fluorescence measurement also decreases. It turned out that apples with an Fv/Fm < 0.7 were unsuitable for valid LOL identification.

The Effect of Aminoethoxyvinylglycine and Dynamic Controlled Atmosphere on the Storage of ‘Bartlett’ Pear

Storage trials of 4 and 8 months’ duration, using ‘Bartlett’ pear (Pyrus communis) fruit treated with and without aminoethoxyvinylglycine (AVG) and stored using ultra low oxygen (ULO) storage (1.5 kPa O2) versus dynamic controlled atmosphere (DCA) (≈ 0.6–0.7 kPa O2) based on chlorophyll fluorescence were conducted over 2 years. AVG applied preharvest and DCA storage produced pears with significantly lower respiration, ethylene, acetaldehyde, ethyl acetate and ethanol post-storage compared to the other treatment combinations. Lower volatiles reflected a higher level of fruit quality. AVG + DCA also exhibited greater green color and firmness retention than the other treatment combinations. There were few disorders in both years of study, with no correlation with field and storage treatments, with the exception of pear scuffing, which was only present in year 2. The incidence of scuffing was positively associated with both fruit softening and yellowing, with DCA + AVG showing the lowest incidence (10%) and ULO + control, the highest (65%). Softening occurred during the shelf life period, as required, and was not an issue for any treatment combination. However, uneven degreening was a concern for fruit treated with DCA + AVG (mainly when firmness at harvest was > 85 N). Future research on higher maturity levels at harvest or reduced AVG rates could address this concern.

Comprehensive responses of aroma production in 'Benihoppe' strawberry to low oxygen associated with the changes of key gene expressions and energy levels.

The influence of low oxygen on the biosynthesis of aroma-related esters and alcohols in strawberries has been well revealed. However, how low-oxygen conditions affect other volatile compounds, such as terpenes and furans, is still to be elucidated. The effects of 2 kPa O2 low oxygen on the biosynthesis of aroma in 'Benihoppe' strawberries were comprehensively investigated in this study. The results showed that, like esters, the accumulations of key terpene alcohols and furans in strawberries were also inhibited by 2 kPa O2 low oxygen during storage and subsequent shelf life, which was associated with the down-regulation of expression of FaNES1 (nerolidol synthase) and FaOMT (O-methyltransferase). However, no anaerobic fermentation occurred in 'Benihoppe' strawberries since no ethanol and acetaldehyde were produced under the 2 kPa O2 condition. As expected, the 2 kPa O2 condition suppressed the respiratory intensity and lowered the energy charge to maintain the quality of strawberries. The negative effects of low-oxygen storage on aroma accumulations and the energy charge of strawberries were more pronounced when transferred to the period of shelf life. The 2 kPa O2 condition caused a full-scale loss of aroma in 'Benihoppe' strawberries, including esters and alcohols as well as terpenes and furans, which was mainly reflected in the reduction of aroma emissions rather than the production of off-flavor, probably due to the reduced expressions of related genes and energy charge. © 2022 Society of Chemical Industry.

Tissue-Specific Recovery Capability of Aroma Biosynthesis in ‘Golden Delicious’ Apple Fruit after Low Oxygen Storage

The impact of low-oxygen (2 kPa) controlled atmosphere storage on the recovery of aroma biosynthesis in ‘Golden Delicious’ (GD) apple tissues during their subsequent shelf life was investigated. The results showed that the highest ester content was found in skin tissue, followed by Flesh 2 and Flesh 1. The 2 kPa O2 storage of GD apples resulted in a decrease in the emission of volatile esters and alcohols, but an increase in aldehyde emission. Notably, compared with skin tissue, the flesh tissue of 2 kPa O2-stored GD apples had a relatively high recovery capacity of ester biosynthesis but a low recovery capacity of alcohol synthesis for its shelf life. The impact was associated with increased levels in the MdLOX1a and MdAATs (MdAAT1 and MdAAT2) transcripts, as well as a decreased level in the MdHPL transcript in the flesh tissue. In addition, a complex regulatory network of ethylene on fruit aroma biosynthesis in response to low-oxygen conditions was also indicated. Collectively, there was a tissue-specific recovery capability of aroma biosynthesis in GD apples after low-oxygen storage.

Tissue-specific recovery capability of aroma biosynthesis in 'Golden Delicious' apple fruit after low oxygen storage

Tissue-specific recovery capability of aroma biosynthesis in 'Golden Delicious' apple fruit after low oxygen storage

Timing of Ethylene Inhibition Affects Internal Browning and Quality of 'Gala' Apples in Long-Term Low Oxygen Storage.

The objective of this study was to evaluate the timing of ethylene inhibition with preharvest and postharvest 1-methylcyclopropene (1-MCP) treatments on internal browning and quality of ‘Gala’ apples in long-term low O2 storage. ‘Gala’ apples were obtained from the same commercial orchard during their harvesting period for 2 years of study. Preharvest 1-MCP orchard spray (3.8% a.i) was applied at the label rate of 60 g 1-MCP per acre in the first year. Postharvest 1-MCP (1 μl L−1) treatments were made for 24 h at 0.5°C either at harvest time (1 day after harvest) or after storage in controlled atmosphere (CA) in both years. Apples were stored in 1.5 kPa O2 + 0.5 kPa CO2 or 0.6 kPa O2 + <0.5 kPa CO2 for 9 months in the first year and 1.5, 1.0, or 0.5 kPa O2 + 0.5 kPa CO2 for 8 months in the second year. Storage regimes with O2 concentrations less than 1 kPa were based on fruit respiration using SafePod™ technology. After removal from storage, all apples were then evaluated for internal browning and other quality attributes after 1, 7, and 14 days at room temperature (RT, 21–22°C). Internal browning developed in ‘Gala’ apples during both years of study, with up to 16% incidence across treatments in the first year and up to 84% in the second year. Apples stored in 0.5–0.6 kPa O2 had significantly less internal browning during both years of study, compared to apples stored in higher O2. The effect of 1-MCP on internal browning was negligible in 0.5–0.6 kPa O2 storage. ‘Gala’ stored in 1.5 kPa O2 and treated with postharvest 1-MCP after storage had significantly less internal browning with preharvest 1-MCP than those without preharvest treatment. Apples treated with postharvest 1-MCP at harvest time, instead of after storage, did not exhibit this same effect. Preharvest 1-MCP-treated fruit maintained greater firmness retention than those without preharvest 1-MCP, and this effect was further enhanced when 1-MCP was applied after storage. Postharvest 1-MCP had no effect on firmness retention in fruit without preharvest 1-MCP, but lower O2 maintained greater firmness in those apples. Preharvest 1-MCP had no significant effect on internal ethylene concentration, whereas it was reduced by postharvest 1-MCP at harvest time in the first year of study, regardless of storage regimes. However, internal ethylene was only affected by storage regime in the second year, with lower concentration in fruit from 0.5 kPa O2 than in those from higher O2. Greasiness developed only in the second year and postharvest 1-MCP consistently reduced it, regardless of treatment timing and storage regime. There was no greasiness in apples treated with postharvest 1-MCP at harvest and then held in 0.5 kPa O2 for 8 months plus 14 days at room temperature. Soluble solids concentration and malic acid content were slightly higher in ‘Gala’ apples with preharvest 1-MCP compared to those without, whereas there was little and inconsistent effect of postharvest 1-MCP on these attributes. Overall, storage regimes with less than 1 kPa O2 provided the least amount of internal browning and best quality attributes. Ethylene inhibition provided further benefits, but this was dependent on the timing of 1-MCP treatment.

Metabolic adaptation of ‘Conference’ pear to postharvest hypoxia: The impact of harvest time and hypoxic pre-treatments

The choice of harvest time and low oxygen storage conditions are crucial parameters in the commercialization of ‘Conference’ pear and the prevention of market losses. To elucidate the effect of harvesting time and hypoxia on the metabolic adaptational responses in pear fruit, a 13C-feeding experiment was performed. Pear tissue disks obtained from fruit harvested at optimum harvest time, or 1 week earlier or later (commercial, early, and late maturity stages, respectively) were exposed for 24 h to 21 kPa O2 followed by 24 h incubation at 0.2 kPa O2 at a constant temperature of 18 °C in a liquid medium containing [U13C] sodium pyruvate. Results showed high fractional enrichment of organic acids, succinate, α-ketoglutarate and lactate, and amino acids, glutamate, and alanine, during hypoxia for all harvesting times suggesting a downregulated TCA cycle stopping at succinate, as suggested by its accumulation, and a possible upregulation of the γ-aminobutyric acid (GABA) shunt. Increased concentration of alanine under hypoxia only in late pears was connected to increased endogenous levels of ethanol and acetaldehyde prior the experiment and lower lactate enrichment. Concentration and fractional enrichment of the optimum harvest time under 0.2 kPa O2 were compared to previously published data from a similar experimental setup where a 4-day gradually declining hypoxic prolife from 21 kPa to 0.2 kPa was implemented. Results showed similar enrichment for all TCA cycle organic acids. Faster label propagation of lactate in the pre-treated tissue suggested faster adaptational mechanisms and an already initiated hypoxic response while higher concentration and enrichment of alanine in the non-acclimated fruit could be evidence of a tissue specific alanine response to sudden oxygen shortage or aneffect of the age of the acclimated sample.

Low Oxygen Storage Improves Tomato Postharvest Cold Tolerance, Especially for Tomatoes Cultivated with Far-Red LED Light

We investigated the effects of low oxygen storage on chilling injury development, colour development, respiration and H2O2 levels of ‘Merlice’ tomatoes cultivated with and without far red (FR) LED lighting during 20 days of shelf-life. Mature green (MG) and red (R) tomatoes were stored at 2 °C in combination with 0.5, 2.5, 5 and 21 kPa O2 for 15 days (experiment 1). MG tomatoes cultivated under either white LED or white LED light with FR LED light were stored at 2 °C in combination with 1, 5 and 21 O2 kPa for 14 days (experiment 2). Chilled MG and R tomatoes from experiment 1 showed decay, firmness loss and higher weight loss during shelf-life which were reduced under low oxygen conditions. FR during cultivation improved chilling tolerance of MG tomatoes. Fastest colour development and lowest respiration rate during shelf-life were observed for MG fruit cultivated with FR lighting prior to storage at 1 kPa O2/0 kPa CO2. H2O2 levels during the shelf-life were not affected during cold storage. The improved cold tolerance of MG tomatoes cultivated with FR lighting is likely due to lower oxygen uptake that led to both higher lycopene synthesis and less softening.

Extremely low-oxygen storage: aerobic, anaerobic metabolism and overall quality of apples at two temperatures

ABSTRACT The objective of this work was to evaluate the effect of extremely low-oxygen storage on the aerobic, anaerobic metabolism and overall quality maintenance of ‘Royal Gala’ and ‘Galaxy’ apples stored at two temperatures. For ‘Royal Gala’ apples, four treatments were evaluated in a two-factor scheme (2 × 2), with two storage conditions: [1] 1.2 kPa O2 + 2 kPa CO2; [2] 0.8 kPa O2 + 1.6 kPa CO2; and two temperatures (1.0 and 1.5 °C). For ‘Galaxy’ apples, the experiment was conducted in a two-factor (3 × 2) scheme with three storage conditions: [1] 1.2 kPa O2 + 2 kPa CO2; [2] 0.8 kPa O2 + 1.6 kPa CO2; [3] 0.4 kPa O2 + 1.2 kPa CO2, and two temperatures (1.0 and 1.5 °C). The ‘Royal Gala’ apples stored under 0.8 kPa O2 + 1.6 kPa CO2 at 1.5 °C had higher flesh firmness, healthy fruit and soluble solids along with lower incidence of flesh breakdown and mealiness. The ‘Galaxy’ apples stored under 0.4 kPa O2 + 1.2 kPa CO2, at temperature of 1.5 °C had lower 1-carboxylic acid-1-aminocyclopropane (ACC) oxidase enzyme activity, ethylene production, occurrence of mealiness, when compared to 1.0 °C. The storage of these two cultivars at 1.5 °C with extremely low O2 partial pressures is possible. The possibility to increase the storage temperature from 1 °C, which is traditionally used for these mutants, to 1.5 °C allows to keep better quality with the advantage of energy saving.

New technology of protecting apple fruits from bitter pit and other physiological diseases during storage

The work was performed in the I. V. Michurin Federal Scientifi c Center (Tambov region, Russia) in 2015-2018. The fruits of Sinap Orlovsky variety with high susceptibility to bitter pit, medium – to superfi cial scald and CO2 -skin injuries were used. The main post-harvest strategy of protecting fruits from bitter pit (BP) is storage in a controlled atmosphere (CA), short-term low oxygen storage (10 days, O2&lt;1 %) reduces losses from scald and BP, but does not provide protection from diseases of varieties with high susceptibility; post-harvest treatment with ethylene biosynthesis inhibitor (1-MCP) provides protection from scald, but has an ambiguous effect on the development of BP, and may increase the degree of disease appearance. The purpose of the research is the development of innovative technology of managing of bitter pit and other post-harvest pathological diseases. In the experiment, the control and 1-MCP-treated fruits were stored at 0 + 1 °C under regular (RA) and controlled atmosphere (CA) conditions: CA-1 (CO2 – 1.2-1.5 %, O2 – 1.2-1.5 %), CA-2 (СО2&lt;0.1 %, О2 – 1.2-1.5 %), under conditions of short (10 days) post-harvest impact of controlled factors: temperature 18-20 °С, О2 – 1.2-1.5 %, CO2&lt;0.1 % and further storage in regular atmosphere (LO2 ). Ethylene, α-farnesen and its oxidation products (CТ281), phenolic compounds were determined in fruits, losses from bitter pit, scald, CO2 -skin injuries, quality (fi rmness) were estimated. 1-MCP-treatment ensured a low level of ethylene and CT281 accumulation in fruits, protection from scald, preservation of fi rmness in all variants of fruit storage, with maximum effi ciency of variants CA-2, CA-1 and LO2 . Fruit protection from bitter pit was provided by CA-2 technology, a signifi cant reduction of losses – LO2 . When using the technology of CA-2, losses from CO2 -skin injuries, noted in the conditions of CA-1, were excluded. The maximum efficiency of protection of fruits from BP, scald, CO2 -injuries is provided by the developed technology CA-2 (CO2&lt;0.1 %, O2 — 1.2-1.5 %).

Influence of respiratory quotient dynamic controlled atmosphere (DCA – RQ) and ethanol application on softening of Braeburn apples

The effect of a respiratory quotient dynamic controlled atmosphere (DCA – RQ), which induces ethanol production through low oxygen storage, and ethanol application on softening of Braeburn apples stored at different temperatures was investigated. DCA – RQ storage was associated with the activation of the alcohol dehydrogenase (ADH) and greater anaerobic metabolism in comparison with DCA – CF (chlorophyll fluorescence) and controlled atmosphere (CA) storage. Greater anaerobic metabolism resulted in lower ethylene production, ACC oxidase activity, membrane permeability, <beta>-galactosidase activity and, therefore, less softening after long-term storage. Ethanol application after CA storage decreased ethylene biosynthesis, respiration rate and membrane permeability. Storage at 3 °C resulted in the lowest soluble solids and acidity, but not softening. In conclusion, Braeburn apples could be stored at 3 °C under DCA – RQ1.5. Additionally, ethanol produced by the fruit, or applied externally, had a significant effect on inhibiting softening during and after storage.

Spatial distribution of gas concentrations and RQ in a controlled atmosphere storage container with pear fruit in very low oxygen conditions

Fruit that is stored in sub-optimal controlled atmosphere (CA) condition is susceptible to internal disorders and off-flavours. Understanding spatial variation in fruit respiration and gas exchange in the storage environment may aid in developing more robust and dynamic storage protocols that prevent unfavourable conditions. A computational fluid dynamics (CFD) model of transport of respiratory gases (O2 and CO2) in a CA storage container with pear fruit was constructed and validated using measured air velocity and gas concentration profiles, and respiratory quotient (RQ) values. The model incorporated the actual pear fruit (cv. ‘Conference’) geometry using a statistical shape model, and filling of the fruit inside the ventilated box was done using discrete element simulations. The model calculates air circulation, fruit respiration kinetics and transport of the respiratory gases in and between the surrounding air and the fruit. The dynamic response of the gas concentrations inside the CA storage system was predicted as a consequence of fruit respiration and air circulation. Air circulation greatly improved the uniformity of the respiratory gas distribution inside the CA storage system. There was a good agreement between the measured and predicted air velocity with an average relative error of 18.61%. The overall average relative error of the predicted O2 and CO2 distribution in the surrounding free air region was 1.90% and 0.63%, respectively. The model revealed that the volumetric average gas concentration and values of RQ inside the pear internal air space and pear cells were different from those measured in the surrounding air of the container. O2 and CO2 concentrations in the fruit were affected by fruit size. Larger fruits showed relatively lower O2 and higher CO2 at the fruit mass centres. During very low oxygen storage (0.22 kPa) with an average RQ = 3.04 in the surrounding air but 5.08 in the cells, the cellular oxygen concentration of the fruits was below the critical concentration for ATP imbalance (0.043 kPa), thereby increasing susceptibility to hypoxia related disorders.

Counting the costs (of low-oxygen storage projects)

The cost in damage caused to earth science collections by pyrite oxidation is well known. But what are the costs of re-housing specimens in low-oxygen microenvironments? This article explores the financial, temporal and spatial costs of a re-storage project, in an attempt to aid collections management planning.

Impact of low oxygen storage on quality attributes including pigments and volatile compounds in ‘Shelly’ mango

Optimal oxygen conditions in controlled atmosphere storage play an important role in maintaining quality and extending shelf life of mangoes, especially for long distance markets. The aim of the study was to investigate the low O2 tolerance limit of 'Shelly' mango fruit based on quality attributes including pigments and accumulation of O2 restricted volatile organic compounds (VOCs). Spectroscopy in the visible wavelength range was applied in diffuse reflectance mode as a non-destructive method for monitoring the pigment contents. Furthermore, the relationship between non-destructively measured pigment indices and pigment content was investigated. The spectral reflectance measurements predicted the pigment content in mango fruit (R2 ≥ 0.70). However, experimental results showed that low O2 had no impact on pigment contents. Soluble solids and individual sugars (sucrose, fructose, and glucose) increased in all storage conditions. Significant differences were found in VOCs, 1% O2 resulted in significant accumulation of anaerobic metabolites: ethanol, ethyl acetate, 3-hydroxy-2-butanone, ethyl butanoate, 1-butanol, 2, 3-butanediol, ethyl propanoate, 2, 3-butanediol, undecane. Sensory analysis indicated that the panelists rejected fruit stored at 1% O2 due to unfavorable odour and taste. The results showed that 5% is the low O2 limit for 'Shelly' mango, below which anaerobic metabolites accumulated compromising the acceptability of the fruit due to ‘off-flavour’. However, storage conditions of 10% O2 can already result in reduced fruit mass loss and respiration rate; maintained the fruit flesh firmness, soluble solids content, and individual sugars in ‘Shelly’ mango after 21 d of storage.

Effect of a low oxygen storage condition on betacyanin and vitamin C retention in red amaranth leaves

We investigated the effects of different O2 concentrations (air or 2 kPa O2) and temperatures (5 °C or 20 °C) on the respiration rate, betacyanin content and VC content to provide basic information on the most optimal conditions for practical storage and transportation of red amaranth. The respiration rates were obviously reduced by low temperatures and low O2 treatments. However, an increase in the CO2 production was detected in red amaranth stored at 20 °C-2 kPa O2 after 30 h. The total betacyanin content changed slightly after storage for 3 days, and there was no significant difference among storage treatments. The VC contents of all the treatments were greatly reduced (more than 50%) after storage. The VC content of red amaranth stored under low temperature either with or without low O2 was not different from the control. Nevertheless, low O2 (2 kPa) at 20 °C significantly slowed the loss of VC. Our results mainly suggested that the O2 level is one of the key factors affecting the quality of red amaranth during storage.

Redness generation via Maillard reactions of whey protein isolate (WPI) and ascorbic acid (vitamin C) in spray-dried powders

Obvious redness generation has been observed in storage and processing for spray-dried WPI-ascorbic acid powders. The lower limit of detection by human observation is 0.001 g/mL for the concentration of ascorbic acid (AA:WPI ratio of 1:100). The redness is related to the adsorption of violet light (380 nm) and blue/green light (500 nm). Fluorescence analysis suggests the formation of formyl threosyl pyrroles and crosslinked poly(amino acids). DSC analysis shows that ascorbic acid peaks disappear as the Maillard reaction progress. The storage temperature has been found to significantly affect the Maillard reactions between WPI and ascorbic acid. Results show that the Maillard reaction rates between WPI and ascorbic acid are fast in spray-dried powders even at 20 °C. The formulated infant/baby milk powders on the market are suggested to require low temperatures (4 °C) or low oxygen (N2 atmosphere) storage to reduce the extents of Maillard reactions (redness generation).