Effect of initial oxygen concentration and film oxygen transmission rate on the quality of fresh‐cut romaine lettuce

Modified atmosphere packaging (MAP) is widely used to maintain the quality of fresh‐cut produce by matching the oxygen transmission rate (OTR) of the packaging film to the respiration rate of the packaged product. The effect of the interaction between film OTR and the initial headspace O₂ on quality of fresh‐cut vegetables has not previously been reported. Romaine lettuce leaves were sliced, washed, dried and packaged with film OTRs of 8.0 and 16.6 pmol s^?1 m^?2 Pa^?1, and with initial headspace O₂ of 0, 1, 2.5, 10 and 21 kPa. Packages were hermetically sealed and stored at 5 °C for up to 14 days. For samples packaged in 16.6 OTR film, increasing the initial headspace O₂ concentration delayed O₂ depletion within the packages, hastened the onset and increased the intensity of discoloration, and inhibited the development of CO₂ injury, acetaldehyde and ethanol accumulation, off‐odors and electrolyte leakage. With 8.0 OTR‐packaged lettuce pieces, ≤1 kPa initial headspace O₂ treatments induced an essentially anaerobic environment within the packages and increased acetaldehyde and ethanol accumulation and off‐odor development. Increasing the initial O₂ concentration above 1 kPa in 8.0 OTR packages transiently increased O₂ concentrations and reduced fermentative volatile production, off‐odors, electrolyte leakage and CO₂ injury. Regardless of initial headspace O₂ concentration, all 16.6 OTR‐packaged samples had severe discoloration after 14 days of storage. Quality was better maintained in 8.0 OTR‐packaged lettuce pieces as the initial headspace O₂ concentration was increased. A 21 kPa initial O₂ treatment of 8.0 OTR‐packaged lettuce maintained good quality throughout storage and had the best overall quality score. Copyright © 2005 Society of Chemical Industry     

Quality of fresh‐cut baby spinach grown under a floating trays system as affected by nitrogen fertilisation and innovative packaging treatments

BACKGROUND: Alternative techniques for cultivation of leafy vegetables such as a floating tray system and unconventional gas mixtures for post‐harvest active modified atmosphere packaging (MAP) could be of interest in the minimally processed vegetable industry. RESULTS: The combined effect of three pre‐harvest fertilisation doses (8, 12 or 16 mmol N L^?1) and three post‐harvest MAP conditions (passive, super‐atmospheric or N₂O‐enriched) on the main quality attributes of fresh‐cut baby spinach leaves throughout 10 days at 5 °C was studied. After 8 days of shelf life, spinach leaves fertilised with 8 and 16 mmol N L^?1 and stored under N₂O‐enriched MAP showed the lowest microbial growth, with good sensory quality. Such combined treatments also preserved the total antioxidant capacity sampled at harvest (8 g ascorbic acid equivalent antioxidant capacity kg^?1 f.w.). A decrease of 10–20% in total vitamin C content regardless of N fertilisation and packaging treatment was found during shelf life. Total phenolics content at harvest was 2 g gallic acid equivalents kg^?1 f.w., which was slightly decreased or preserved during shelf life while total chlorophylls were preserved for all treatments assayed around 550 mg kg^?1 f.w. CONCLUSION: No clear effect of fertilisation doses was observed during post‐harvest storage on overall quality of fresh‐cut baby spinach leaves, while N₂O‐enriched atmospheres seems to be a promising alternative to passive MAP for extending shelf life. Copyright © 2010 Society of Chemical Industry     

Removal of soluble organic carbon from winery and distillery wastewaters by application to soil

A logistic model was used to describe the removal of water-soluble carbon from synthetic winery and distillery wastewaters containing ¹⁴C-labelled lactic acid and glycerol after their application to the top-soils of a brown earth and a solod. Decreases in the radioactivity of soil extracts during the first hour after application were ascribed to microbial uptake and adsorption. Oxidative microbial decay was responsible for the removal of the remaining ¹⁴C of the solution to concentrations of less than 5% of the applied ¹⁴C, with removal times dependent on the duration of a lag period (when present) and the rate of decay. Soils from existing wastewater disposal sites containing adapted populations of micro-organisms had shorter lag periods and faster rates of oxidative decay than newly exposed soils. When the loading of organic material was increased, higher concentrations of added ¹⁴C remained in the soil solution after initial microbial uptake or adsorption, and the lag periods were often prolonged. Their combined effects could not be fully offset by concurrent increased rates of oxidative microbial decay, which overall resulted in longer removal times. The disappearance of extractable ¹⁴C to concentrations of less than 5% of input ¹⁴C was used as the basis for determining the minimum times required between successive irrigations with wastewater, which increased in the order of acclimatised solod (0.3–1.4 d) < acclimatised brown earth (0.7–2.6 d) < non-acclimatised brown earth (1.1–4.5 d) < non-acclimatised solod (0.7–4.8 d). Estimates based on the evolution of ¹⁴CO₂were found to be less reliable, due to the continuous turnover of the ¹⁴C of the biomass after the extractable ¹⁴C had disappeared.     

Trials to Reduce Nitrate and Oxalate Content in Some Leafy Vegetables. 2. Interactive Effects of the Manipulating of the Soil Nutrient Supply,Different Blanching Media and Preservation Methods Followed by Cooking Process

Experiments were carried out to find ways to prevent undesirably high nitrate contents in lettuce and high nitrate and oxalate contents in spinach. Treatments included manipulating the soil nutrient supply and the effects of processing and cooking on the reduction of nitrate and oxalate contents, and the maintenance of vitamins and minerals in the spinach. Best lettuce and spinach qualities, ie highest vitamin and mineral contents with lowest nitrate and oxalate levels, were achieved by fertilising them either with farm yard manure (FYM) or Ca(NO₃)₂+(NH₄)₂SO₄(1: 1)+N-serve (nitrification inhibitor), at the rate of 178·5 kg N ha^-1. High spinach yields were also obtained by fertilisation with urea at 178·5 kg N ha^-1, but resulted in high nitrate and oxalate levels. Losses of vitamins A, B₁, B₂, niacin and C as well as minerals Ca, Fe, Mg, Na, K and P from spinach were smaller following freezing compared with canning, especially when 0·1% calcium citrate and 0·01% sodium ascorbate solutions were used for blanching at ∽77°C for 2 min. © 1997 SCI.     

Can δ15N in lettuce tissues reveal the use of synthetic nitrogen fertiliser in organic production?

BACKGROUND: The nitrogen isotopic fingerprint (δ¹⁵N) is reported to be a promising indicator for differentiating between organically and conventionally grown vegetables. However, the effect on plant δ¹⁵N of split nitrogen fertilisation, which could enable farmers to cover up the use of synthetic fertiliser, is not well studied. In this study the use of δ¹⁵N in lettuce as a potential marker for identifying the use of synthetic nitrogen fertiliser was tested on pot‐grown lettuce (Lactuca sativa L.) treated with synthetic and organic nitrogen fertilisers (single or split application). The effect of combined usage of synthetic and organic fertilisers on δ¹⁵N was also investigated. RESULTS: The δ¹⁵N values of whole plants treated with different fertilisers differed significantly when the fertiliser was applied in a single treatement. However, additional fertilisation (with isotopically the same or different fertiliser) did not cause a significant alteration of plant δ¹⁵N. CONCLUSION: The findings of the study suggest that the δ¹⁵N value of lettuce tissues could be used as a rough marker to reveal the history of nitrogen fertilisation, but only in the case of single fertiliser application. However, if the difference in δ¹⁵N between the applied synthetic and organic nitrogen fertilisers was > 9.1‰, the detection of split and combined usage of the fertilisers would have greater discriminatory power. Copyright © 2010 Society of Chemical Industry     

Degradation and metabolism of 14C‐labelled proanthocyanidins from carob (Ceratonia siliqua) pods in the gastrointestinal tract of the rat

The aim of the work was to study the binding, degradation and metabolism of dietary condensed tannins in the gastrointestinal tract of an omnivore. Young pods of carob (Ceratonia siliqua L) were radiolabelled by in vivo feeding of ¹⁴CO₂, trans‐[U‐¹⁴C]cinnamate or L ‐[U‐¹⁴C]phenylalanine. [¹⁴C]Proanthocyanidins (condensed tannins) were extracted with acetone/water (3:1 v/v), isolated on Sephadex LH‐20 and fed to rats by gavage. After 4 and 18 h, 90–94% of the gavaged ¹⁴C was in the gut contents and/or faeces. Much of the gavaged ¹⁴C (57%), predominantly that originally in tannins of high degree of polymerisation (DP), became insolubilised, mainly in the form of protein–tannin complexes. Some of the [¹⁴C]tannins that remained soluble decreased in DP, especially in the small intestine and caecum. A further fraction (12% of the ¹⁴C gavaged) underwent chemical modifications in the gut to form soluble, non‐tannin compounds. Small proportions of the ¹⁴C were found in the liver (1.0–1.5%), urine (1–2%) and ¹⁴CO₂ (1–2%). We conclude that proanthocyanidins are not inert within the gut but undergo various modifications which may affect the nutrition of the animal. © 2001 Society of Chemical Industry     

Antioxidant properties and shelf‐life extension of fresh‐cut tomatoes stored at different temperatures

BACKGROUND: The feasibility of using modified atmosphere packaging (5 kPa O₂ + 5 kPa CO₂) to maintain the antioxidant properties of fresh‐cut tomatoes during shelf‐life was assessed through storage at different temperatures (5, 10, 15 and 20 °C). Health‐related compounds, antioxidant capacity, microbiological counts, physicochemical parameters and in‐package atmosphere of tomato slices were determined. RESULTS: Initial lycopene, vitamin C and phenolic contents and physicochemical parameters of tomato slices were well maintained for 14 days at 5 °C. Lycopene and total phenolic contents were enhanced over time in tomato slices stored at 15 and 20 °C. However, this increase in antioxidant compounds of fresh‐cut tomatoes during storage may be associated with excessive amounts of CO₂ (R² = 0.5679–0.7328) in the packages due to microbial growth. Although keeping tomato slices at temperatures above 10 °C increased their antioxidant content, the shelf‐life of the product was reduced by up 4 days. CONCLUSIONS: A storage temperature of 5 °C is appropriate for maintaining the microbiological shelf‐life of fresh‐cut tomatoes for up to 14 days and also allows the antioxidant properties of tomato slices to be retained over this period, thus reducing wounding stress and deteriorative changes. Copyright © 2008 Society of Chemical Industry     

On fumonisin incidence in monoculture maize under no‐till,conventional tillage and two nitrogen fertilisation levels

BACKGROUND: Fusarium ear rot and fumonisin contamination are serious problems for maize growers. The lack of maize genotypes highly resistant to fumonisin contamination emphasises the need for management strategies to prevent contamination by this mycotoxin. There are conflicting reports regarding no‐till and nitrogen (N) fertilisation practices in relation to the incidence of fumonisins. In this study the effect of no‐till compared with conventional tillage and of N fertilisation rates on fumonisin occurrence was investigated over three years in Northern Italy. RESULTS: The average contamination of grain by fumonisins B₁ and B₂ over the three years was significantly different, with a lower value in 2000 (516 µg kg^?1) than in the other years (5846 and 3269 µg kg^?1 in 2001 and 2002 respectively). Conventional tillage and no‐till treatments had no significant effect on the incidence of fumonisins. This finding suggests that above‐ground residues infected by Fusarium would not lead to an increase in fumonisin incidence. However, N fertilisation significantly increased fumonisin levels, by 99 and 70% in 2000 and 2001 respectively. CONCLUSION: Maize monoculture does not show a cumulative effect on the occurrence of fumonisins, while high rates of N fertiliser consistently result in elevated fumonisin levels. Both these effects can be influenced by annual meteorological fluctuations. Copyright © 2008 Society of Chemical Industry     

Respiratory parameters of onion bulbs (Allium cepa) during storage. Effects of ionising radiation and temperature

The O₂ and CO₂ respiration rates of untreated and irradiated onion bulbs (Allium cepa) at 0.15 and 0.30 kGy were measured at 4, 10 and 20 °C. The O₂ respiration rate increased for 24 h after treatment from 0.19 mmole kg⁻¹ h⁻¹ at 20 °C for control samples up to 0.26 and 0.39 mmole kg⁻¹ h⁻¹ for 0.15 and 0.3 kGy irradiated onions respectively. Respiratory quotient (RQ) increased with temperature. The Q₁₀ of the respiration of the control samples (1.61) was lower than that of any other plant tissue, but it increased with storage duration and irradiation dose. The respiration rate of control onions increased steadily over 25 weeks of storage at 4 °C, while that of the irradiated samples decreased during the same period after a peak observed after irradiation treatment. The apparent K_m for the Menten–Michaelis equation was determined on a new respirometer and averaged 1.6 kPa at 10 °C and 6.3 kPa at 20 °C. However, at this higher temperature (20 °C) apparent K_m varied with O₂ partial pressure, proving that the respiration of onion bulbs does not follow a Menten–Michaelis‐like process. The Fermentative Index (FI) of onions was measured under anoxic conditions as CO₂ production rates in mmole kg⁻¹ h⁻¹ at 4, 10 and 20 °C. © 2000 Society of Chemical Industry     

Continuous dense‐phase CO2 processing of a coconut water beverage

Effects of dense‐phase CO₂ (DPCD) on microbial, physical, chemical and sensorial quality of coconut water (CW) beverage were evaluated. Pressure during DPCD treatment was not significant in microbial reduction whereas temperature and % CO₂ levels were significant. DPCD‐treated (34.5 MPa, 25 °C, 13% CO₂, 6 min), heat‐pasteurised (74 °C, 15 s) and untreated CW beverages were evaluated during 9 weeks of refrigerated storage (4 °C). Total aerobic bacteria of DPCD and heat‐treated samples decreased whereas that of untreated samples increased to >10⁵ CFU mL^?1 after 9 weeks. DPCD increased titratable acidity but did not change pH (4.20) and °Brix (6.0). Likeability of DPCD‐treated CW was similar to untreated. Heat‐treated samples were less liked (α = 0.05) at the beginning of storage. Off flavour and taste‐difference‐from‐control scores of heated samples were higher than DPCD during the first two weeks. DPCD extended shelf life of acidified, sweetened and carbonated CW over 9 weeks at 4 °C.     

A lysimeter study of nitrate leaching, optimum fertilisation rate and growth responses of corn (Zea mays L.) following soil amendment with water-saving super-absorbent polymer

BACKGROUND: Nitrate leaching and the resulting groundwater contamination from intensive cereal production has become a major concern for long‐term farmland efficiency and environmental sustainability in northern China. The aim of this study was to evaluate a water‐saving super‐absorbent polymer (SAP) for minimising NO₃^? leaching from soil and optimising corn growth and yield. Thirty‐six undisturbed soil lysimeters were installed in a field lysimeter facility in drought‐affected northern China to study the growth and yield characteristics of summer corn (Zea mays L.) as well as the amount of NO₃–leaching losses under different fertiliser (standard, medium or 75% and low, or 50% of conventional fertilisation rate) and SAP (control, 0; level‐1, 15 kg ha^?1 and level‐2, 30 kg ha^?1) treatments. RESULTS: Corn yield fell by 19.7% under medium and 37.7% under low fertilisation; the application of SAP increased yield significantly by 44.4% on level‐1 and 80.3% on level‐2. Similarly, plant height, leaf area, number of grains as well as protein, soluble sugar and starch contents in the grain also increased with SAP treatment. Application of SAP at 30 kg ha^?1 plus half of conventional fertilisation can reduce maximum (64.1%) nitrate leaching losses from soil. CONCLUSIONS: Application of SAP at 30 kg ha^?1 plus only half the amount of conventional fertiliser rate (150 kg urea, and 50 kg each of superphosphate and potassium sulfate) would be a more appropriate practice both for minimising nitrate leaching and sustainable corn production under the arid and semiarid conditions of northern China. Copyright © 2011 Society of Chemical Industry     

Interaction between nitrogen and sulfur by foliar application and its effects on flour bread‐making quality

BACKGROUND: Optimization of nitrogen (N) and sulfur (S) nutrition of wheat influences the bread‐making quality of grain. This study was conducted to determine whether the application of N and S in winter wheat at anthesis stage during two field trials could influence the absorption and distribution of N and S in grain and flour bread‐making quality RESULTS: The incorporation of ¹⁵N and ³⁴S tracers in various plant parts (leaves, stems, spikes) was determined by isotopic ratio mass spectrometry coupled with an elemental analyser (EA‐IRMS). The effects of foliar fertilization on percentage of ¹⁵N and ³⁴S recovery in various plant parts, grain yield, flour protein content, and dough properties were investigated after a combination of treatments: N (urea), S (micronized elemental S) and NS (both urea and micronized elemental S). Nitrogen (70–80%) and S (35–55%) were quickly assimilated during the days following application. Sixty days after application, 42–68% N and 6–12% S were recovered in the grain. When N and S fertilizers were applied simultaneously, N and S recoveries (68% and 12%), N/S ratios (11–14), flour protein content (115 g kg^?1) and dough strength (310 × 10^?4 J), swelling (21.8 mmH₂O) and extensibility (96.4 mm) were increased. CONCLUSION: A synergistic effect between the foliar applied N and S fertilizers appears to increase N and S assimilation in grain and may improve bread‐making qualities. Copyright © 2007 Society of Chemical Industry     

Variation of organic carbon and nitrogen in aggregate size fractions of a paddy soil under fertilisation practices from Tai Lake Region,China

Long‐term changes in agricultural management can affect soil organic carbon (SOC) and nutrient dynamics, which can be monitored by determining the distribution of microbial activity and nutrient pools in soil aggregates of different size fractions. The objective of the present study was to investigate the changes in SOC and total nitrogen (N_t) distribution in aggregates of different size fractions from a paddy soil (Ferric‐accumulic Stagnic Anthrosols) under a long‐term fertilisation trial. Undisturbed samples of topsoil (0–5 and 5–15 cm depths) were collected from a field experiment farm located in Tai Lake Region, China, with the plots receiving no fertiliser (NF), chemical fertilisers (CF), chemical fertilisers with straw return (CFS) or chemical fertilisers plus pig manure (CFM). In the surface layer, SOC and N_t concentrations appeared as a bimodal peak in the 2000–250 and < 2 µm fractions. SOC concentration increased by 38.6, 40.8 and 17.2% and N_t concentration by 30.0, 16.8 and 38.4% in the 2000–250 µm fractions under CFM, CFS and CF respectively as compared with NF treatment. There were slight changes in SOC and N_t in the < 2 µm fractions from different fertilisation plots. Continuous addition of manure or straw increased storage of SOC and N_t mainly in the coarser aggregate fractions. SOC increases due to straw or pig manure application predominated in the 2000–250 µm fractions, with SOC seeming to be physically protected within macro‐aggregates. Thus straw and manure are likely to play an important role in carbon and nitrogen storage in paddy soil under long‐term combined chemical and organic fertilisation. Copyright © 2007 Society of Chemical Industry     

Metabolism of citric and malic acids during ripening of tomato fruit

Tomato fruit at various stages of ripeness were injected with ¹⁴C-labelled citric and malic acids. The ¹⁴CO₂ evolved by individual fruit was determined over a 72 h period and the fruit then analysed for the incorporation of ¹⁴C into sugars, amino acids and individual non-volatile organic acids. In mature green tomato fruit citric and malic acids were found to be metabolised to a comparable extent. Appreciable interconversion occurred together with oxidation to CO₂ and some labelling of glutamic acid and glutamine. In red fruit, citric acid was not as readily oxidised to CO₂ and little conversion to malic acid was observed. On the other hand, malic acid was oxidised to CO₂ and converted to citric acid as rapidly as in green fruit with, in addition, appreciable conversion to glutamic acid. These results are discussed in relation to the changes in concentration of the endogenous acids which take place during the ripening of tomato fruit.     

Microflora and Color of Ground Beef in Gas Exchange Modified Atmosphere Packaging with Abusive Display Temperatures

Gas exchange modified atmosphere packaging (GEMAP) with display gas of 80% O²:20% CO₂ retarded microbial growth and improved color stability of ground beef patties compared with vacuum packaging (VP) followed by air‐permeable polyvinylchloride (PVC) overwrapping during 3 d of retail display. Predominant microorganisms for GEMAP were Pseudomonas, Yersinia, Aeromonas, and Enterobacter and for VP‐PVC were Pseudomonas, Brochothrix, Aeromonas, Enterobacter, Moraxella, and Lactobacillus. Lower levels of pathogens were isolated in GEMAP samples with 7 °C than 15 °C display temperature. Patties were darker (lower L*) with those with 15 °C than with 7 °C display and redder (higher a*) in GEMAP than VP‐PVC. Good manufacturing practices should be followed with MAP meat to reduce the risk of pathogenic microbial growth.     

Changes in appearance and natural microflora on iceberg lettuce treated in warm,chlorinated water and then stored at refrigeration temperature

The objective of this study was to determine the effect of warm, chlorinated water on the survival and subsequent growth of naturally occurring microorganisms and visual quality of fresh-cut iceberg lettuce. After dipping cut lettuce leaves in water containing 20 mg l⁻¹free chlorine for 90 s at 50°C, samples were stored at 5 or 15°C for up to 18 or 7 days, respectively. Populations of aerobic mesophiles, psychrotrophs, Enterobacteriaceae, lactic acid bacteria, and yeasts and molds were determined. The visual appearance and development of brown discoloration were monitored. Treatment of lettuce in warm (50°C) chlorinated water delayed browning of lettuce. Shelf life of lettuce stored at 5°C, as determined by subjective evaluation of color and general appearance, was about 5 days longer than that of lettuce stored at 15°C. Treatment in warm (50°) water, with or without 20 mg l⁻¹chlorine, and in chlorinated water at 20°C significantly (α= 0·05) reduced the initial population of mesophilic aerobic microflora by 1·73–1·96 log₁₀cfu g⁻¹. Populations increased, regardless of treatment, as storage time at 5°C and 15°C increased. The same trends were observed in populations of psychrotrophs and Enterobacteriaceae. Yeast populations increased slightly in lettuce stored at 5°C but were consistently about 3 logs lower than mesophilic aerobes. Populations of molds and lactic acid bacteria were less than 2 log₁₀cfu g⁻¹throughout storage at 5 or 15°C. Results suggest that heat (50°C) treatment may have delayed browning and reduced initial populations of some groups of micro-organisms naturally occurring on iceberg lettuce, but enhanced microbial growth during subsequent storage.     

Quality of white cabbage yield and potential risk of ground water nitrogen pollution,as affected by nitrogen fertilisation and irrigation practices

BACKGROUND: The effect of different fertilisation (broadcast solid NPK application and fertigation with water‐soluble fertiliser) and irrigation practices (sprinkler and drip irrigation) on yield, the nitrate content in cabbage (Brassica oleracea var. capitata L.) and the cabbage N uptake was detected, in order to assess the potential risk for N losses, by cultivation on sandy–loam soil. The N rate applied on the plots was 200 kg N ha^?1. RESULTS: The highest yield (93 t ha^?1) and nitrate content (1256 mg kg^?1 DW) were found with treatments using broadcast fertilisation and sprinkler irrigation. On those plots the negative N balance (?30 kg N ha^?1) was recorded, which comes mainly from the highest crop N uptake (234 kg N ha^?1) indicating the lowest potential for N losses. CONCLUSION: In terms of yield quality and the potential risk for N losses, broadcast fertilisation combined with sprinkler irrigation proved to be the most effective combination among the tested practices under the given experimental conditions. The importance of adequate irrigation is also evident, namely in plots on which 50% drip irrigation was applied, the lowest yield was detected and according to the positive N balance, a higher potential for N losses is expected. Copyright © 2011 Society of Chemical Industry     

Effects of controlled atmosphere storage on respiratory metabolism of apple fruit tissue

The effects of CO₂ and O₂ concentrations commonly used in fruit storage upon various respiratory processes in apple fruit tissue have been investigated. In manometric experiments 10% CO₂ inhibited CO₂ release from succinate supplied to peel discs by over 50%; CO₂ release from malate was inhibited at high substrate concentrations, while CO₂ release from pyruvate was not affected. High CO₂ concentrations also inhibited ¹⁴CO₂ release from succinate 1,4-¹⁴C and succinate 2,3-¹⁴C supplied to peel discs. It is concluded that succinate dehydrogenase is the respiratory enzyme most affected by CO₂ concentration. Oxygen uptake was found to be 50% inhibited at ambient concentrations of 0.5% O₂ for cortical tissue and 5% O₂ for peel tissue. It is concluded that cytochrome oxidase is responsible for O₂ uptake in peel and cortical tissue. The apparent low affinity for O₂ in peel respiration may be due to limited O₂ diffusion through the tissue. It is concluded that O₂ uptake by the bulk of the apple is not directly affected by O₂ concentrations employed in fruit storage.     

Modeling Respiration Rate of Strawberry (cv. San Andreas) for Modified Atmosphere Packaging Design

A model for strawberry (Fragaria × ananassa cv. San Andreas) respiration rate was determined as a function of O₂ and CO₂ concentrations and temperature. Strawberries were enclosed in containers under different gaseous compositions (0–24% O₂ and 0–15% CO₂) and temperatures (10, 19, 23°C). Respiration rate was determined as O₂ consumption and CO₂ production. Respiration rate data was fitted to Michaelis-Menten models, with temperature dependence according to Arrhenius type equation. Non–linear regression was applied to calculate model parameters. No CO₂ inhibition was verified, so a simple Michaelis–Menten model was selected (R² = 0.91).