Dehydration kinetics of red pepper (Capsicum annuum L var Jaranda)

Shredded and whole red pepper samples were dehydrated in a laboratory drier with a through‐flow air velocity of 0.5 m s^?1 at 50, 55, 60 and 70 °C. Shredded peppers dried faster than whole peppers. The drying behaviour of whole samples was characterised by a constant‐ and a falling‐rate drying period, whilst that of shredded samples was characterised by a falling‐rate drying period only. The mass transfer coefficient for whole samples during the constant‐rate period was computed experimentally. The effect of temperature on the mass transfer coefficient was described by the Arrhenius model. The activation energy was 58 kJ mol^?1. In the falling‐rate period the mass transfer was described by a diffusional model, and the effective diffusion coefficient at each temperature was determined. Diffusion coefficients were estimated to lie between 4.38 × 10^?11 and 10.99 × 10^?11 m² s^?1 for whole peppers and between 37.23 × 10^?11 and 99.61 × 10^?11 m² s^?1 for shredded peppers. The effect of temperature on the effective diffusion coefficient was described by the Arrhenius equation, with an activation energy of 44 kJ mol^?1 for whole peppers and 56 kJ mol^?1 for shredded peppers. © 2003 Society of Chemical Industry     

Microbial Population of Shredded Carrot in Modified Atmosphere Packaging as Related to Irradiation Treatment

Shredded carrots in modified atmosphere packaging were treated with low-dose irradiation of 0.5 kGy in order to determine whether additional reduction of microbial population would be achieved for carrots previously treated with chlorine. Commercially prepared shredded carrots treated with irradiation had a mean microbial population of 1300 CFU/g at the expiration date (9 days after irradiation) compared with 87,000 CFU/g for nonirradiated, chlorinated controls. Oxygen content of the headspace gas and ethanol content of the carrots were not significantly affected. Irradiation appears to be a suitable technology for shredded carrots.     

Physiological properties of fresh‐cut watermelon (Citrullus lanatus) in response to 1‐methylcyclopropene and post‐processing calcium application

Seedless watermelon (Citrullus lanatus Thunb. Mansfeld, cv. Millionaire) fruit were exposed to 10 µL L⁻¹ 1‐methylcyclopropene (1‐MCP) or air for 18 h. Afterward, the fruit were processed into placental‐tissue pieces, treated with calcium dips (20 g kg⁻¹ CaCl₂) or deionized water, and stored in vented containers for 7 days at 10 °C. At intervals during storage, fresh‐cut placental tissue was monitored for respiration, ethylene production, firmness, electrolyte leakage, total soluble solids, titratable acidity and microbial growth. Ethylene production was below detection in fresh‐cut placental tissue, consistent with the low ethylene production in intact watermelon fruit. Respiration rates were significantly enhanced in response to tissue processing, and continued to increase throughout the 7 days of storage. Tissue derived from 1‐MCP‐treated fruit showed enhanced 1‐aminocyclopropane‐1‐carboxylate synthase (ACS, EC 4.4.1.14) activity, suppressed respiratory rates and undetectable levels of 1‐aminocyclopropane‐1‐carboxylate oxidase (ACO) activity during storage. Post‐processing calcium dips (CaCl₂) had little influence on ACS activity relative to tissue not receiving calcium, but significantly enhanced ACO activity and maintained firmness of fresh‐cut tissue throughout storage. The data collectively support the conclusion that 1‐methylcyclopropene treatment of intact watermelon fruit is alone unlikely to benefit the storage duration of fresh‐cut watermelon. Copyright © 2005 Society of Chemical Industry     

Use of 1‐methylcyclopropene to extend the postharvest life of lettuce

This study examined the effect of fumigation of iceberg lettuce with 1‐methylcyclopropene (1‐MCP) at 0.1–1 µl l^?1 for 1–5 h on the storage life at 5 °C in air containing 0.1 µl l^?1 ethylene. 1‐MCP extended the storage life of shredded lettuce at all concentrations, with the optimal treatment being fumigation with 0.1 µl l^?1 1‐MCP for 1 h at 5 °C, which resulted in an extension in storage life of about 50% over untreated lettuce. Application of this treatment to whole lettuce heads resulted in a 100% increase in storage life. 1‐MCP thus appears to be of considerable commercial potential for the lettuce industry. © 2002 Society of Chemical Industry     

Quality Maintenance of "Ready-to-eat" Shredded Carrots by Gamma Irradiation

Shredded carrots were either chlorinated, rinsed, and spin-dried as in industrial processes, or irradiated (2 kGy), replacing the three steps. Several factors defining the quality of minimally processed vegetables were monitored during storage at 10°. Atmospheres inside micro-porous plastic bags stabilized at 7–15% O₂ and 10–15% CO₂. Sugar levels in tissues were twice as high in irradiated samples as in chlorinated ones. Irradiation also prevented losses of orange color and carotenes. Growth of aerobic mesophilic and lactic microflora was strongly inhibited by irradiation. Sensory analysis demonstrated preferences for irradiated vegetables. Irradiation, avoiding three potential denaturing steps preserved “ready-to-eat” shredded carrots with better quality than those prepared by conventional industrial processes.     

Improvement of L(+)‐lactic acid production from cassava wastewater by Lactobacillus rhamnosus B 103

BACKGROUND: L (+)‐Lactic acid is used in the pharmaceutical, textile and food industries as well as in the synthesis of biodegradable plastics. The aim of this study was to investigate the effects of different medium components added in cassava wastewater for the production of L (+)‐lactic acid by Lactobacillus rhamnosus B 103. RESULTS: The use of cassava wastewater (50 g L^?1 of reducing sugar) with Tween 80 and corn steep liquor, at concentrations (v/v) of 1.27 mL L^?1 and 65.4 mL L^?1 respectively led to a lactic acid concentration of 41.65 g L^?1 after 48 h of fermentation. The maximum lactic acid concentration produced in the reactor after 36 h of fermentation was 39.00 g L^?1 using the same medium, but the pH was controlled by addition of 10 mol L^?1 NaOH. CONCLUSION: The use of cassava wastewater for cultivation of L. rhamnosus is feasible, with a considerable production of lactic acid. Furthermore, it is an innovative proposal, as no references were found in the scientific literature on the use of this substrate for lactic acid production. Copyright © 2010 Society of Chemical Industry     

Bioactivity of falcarinol and the influenceof processing and storage on its content in carrots (Daucus carota L)

The concentration‐dependent activity of the polyacetylene falcarinol ((9Z)‐heptadeca‐1,9‐dien‐4,6‐diyn‐3‐ol), isolated from carrots, was investigated in a bioassay with primary mammary epithelial cells in collagen gels and compared with that of β‐carotene, the orange pigment in carrots. Falcarinol showed biphasic activity, having stimulatory effects between 0.01 and 0.05 µg ml^?1 and inhibitory effects between 1 and 10 µg ml^?1, whereas β‐carotene showed no effect in the concentration range 0.001–100 µg ml^?1. The results are discussed in relation to the health‐promoting effects of carrots and related vegetables. Falcarinol was quantified in the carrot cultivars Bolero, Rodelika and Fancy by analytical reverse phase HPLC, subjected to various processing and storage conditions in order to study how long‐term storage, blanching, freezing and boiling influence the content of falcarinol. Long‐term storage of raw carrot cubes (1 cm³) reduced the falcarinol content by almost 35%. A similar reduction was found in steam‐blanched carrot cubes (1 cm³). Long‐term storage at ?24 °C of steam blanched carrot cubes did not reduce the falcarinol content further. A reduction of almost 70% in the falcarinol content was found in carrot pieces boiled in water for 12 min compared with raw carrots. Copyright © 2003 Society of Chemical Industry     

Influence of hydroponic and soil cultivation on quality and shelf life of ready-to-eat lamb's lettuce (Valerianella locusta L. Laterr)

BACKGROUND: Nowadays, there is an increasing interest in the hydroponic floating system to cultivate leafy vegetables for ready‐to‐eat salads. It is reasonable that different growing systems could affect the quality and shelf life of these salads. RESULTS: The quality and shelf life of ready‐to‐eat lamb's lettuce grown in protected environment in soil plot or in soil‐less system over hydroponic solution with or without the addition of 30 µmol L^?1 silicon were evaluated. Minimum effects were observed on colour, firmness and microbial counts. Hydroponic cultivation largely affected plant tissue hydration, leading to weight loss and structural modifications during refrigerated storage. The shelf life of lamb's lettuce was limited by the development of visually detectable unpleasant sensory properties. Shelf life, calculated by survival analysis of consumer acceptability data, resulted about 7 days for soil‐cultivated salad and 2 days for the hydroponically grown ones. The addition of silicon to the hydroponic solution resulted in an interesting strategy to increase plant tissue yield and reduce nitrate accumulation. CONCLUSIONS: Although hydroponic cultivation may have critical consequences on product quality and shelf life, these disadvantages could be largely counterbalance by increased yield and a reduction of nitrate accumulation when cultivation is performed on nutritive solutions with supplemental addition of silicon. Copyright © 2011 Society of Chemical Industry     

Evaluation of a pre-cut heat treatment as an alternative to chlorine in minimally processed shredded carrot

The effect of a pre-cut heat treatment (100 °C/45 s) as an alternative decontamination treatment to chlorinated-water (200 ppm active chlorine/1 min, 5 °C) was evaluated in minimally processed carrot (shredded). The quality of shredded carrots was studied just after minimal processing and during storage at 5 °C (10 days) by evaluating microbial (total mesophilic aerobic, yeast and moulds and lactic acid bacteria counts), physical–chemical (soluble solids content, pH, titratable acidity, whiteness index), physiological (peroxidase activity and headspace analysis) and sensorial attributes (colour, fresh-like appearance, aroma and general acceptance). The relationships between sensory perception of undesired changes, microbial contamination threshold, physico-chemical and physiological indices were investigated and compared between heat-treated and control samples. The use of heat in pre-cut carrot proved to be more efficient than chlorinated-water concerning microbial control (threshold concentration of 7 Log₁₀ cfu g^? 1), providing an acceptable fresh-like quality product during 10 days of storage (5 °C), which corresponds to a 3-day shelf-life extension compared to control samples. Heat-treated shredded carrot showed lower respiratory and POD activities than chlorinated samples suggesting that the use of heat provides a metabolic activity lowering effect besides the microbial effect which could be important to shelf-life extension of the fresh-cut product.Industrial relevanceIn minimally processed vegetables, namely in shredded carrot, chlorine solutions have been widely used by the industry for sanitization purposes. However, reduced microbiological efficiency allied to sensorial changes and eventual formation of carcinogenic chlorinated compounds pointed out the need for alternative decontamination methodologies. Also, the evermore conscious consumers are demanding minimization of the potentially negative impact of food processing on human health and the environment. From the practical experience of a fresh-cut industry directly involved in the R&D research project which supported this study, the marketability of minimally processed shredded carrot is limited due to rapid microbial growth and colour loss (decrease of orange intensity and/or whitening of the shreds). As a result, a pilot-plant scale study was performed, evaluating quality attributes of shredded carrot processed according to a clean pre-cut alternative decontamination process.     

Pulsed electric field treatment of carrots before drying and rehydration

BACKGROUND: In this study the effects of pulsed electric field (PEF) pretreatment were evaluated during drying and rehydration of carrots. Carrots pretreated with an electric field intensity of 1 kV cm^?1 (capacitance 0.5 µF, 20 pulses) or 1.5 kV cm^?1 (capacitance 1 µF, 20 pulses) as well as blanched (100 °C, 3 min) carrots were used for the study. Following pretreatment, samples were oven dried at 70 °C and then rehydrated in distilled water (1:30 w/v) at room temperature (24 ± 1 °C). RESULTS: PEF pretreatment increased the drying rate of carrots. However, the rehydration rate of PEF‐pretreated carrots was lower than that of blanched carrots. There were no colour differences between PEF‐pretreated and blanched carrots before drying and after rehydration. In terms of texture, PEF‐pretreated carrots were firmer than blanched carrots. PEF pretreatment reduced the activity of peroxidase by 30–50%, while blanching completely inactivated the enzyme (>95%). CONCLUSIONS: Overall, the results suggest that PEF could be an effective pretreatment during drying and rehydration of carrots. Copyright © 2009 Society of Chemical Industry     

Isolation of eriocitrin (eriodictyol 7‐O‐rutinoside) as an arachidonate lipoxygenase inhibitor from Lumie fruit (Citrus lumia) and its distribution in Citrus species

An inhibitory compound acting against rat platelet 12‐lipoxygenase was isolated from the peel of Lumie fruit (Citrus lumia) by activity‐guided separation. It was identified as eriocitrin (eriodictyol 7‐O‐rutinoside) by spectroscopic analyses. Eriocitrin inhibited 5‐lipoxygenase (IC₅₀29.1 µmol L^?1) from rat peritoneal polymorphonuclear leukocytes in addition to 12‐lipoxygenase (IC₅₀22.3 µmol L^?1). Its aglycone, eriodictyol (5,7,3′, 4′‐tetrahydroxyflavanone), was a much more potent inhibitor of both 12‐lipoxygenase (IC₅₀0.07 µmol L^?1) and 5‐lipoxygenase (IC₅₀0.20 µmol L^?1). It also inhibited the production of leukotriene B₄ in intact peritoneal polymorphonuclear leukocytes stimulated with calcium ionophore A23187 (IC₅₀12.7 µmol L^?1). The distribution of eriocitrin in 39 citrus fruits was investigated by high‐performance liquid chromatography analysis. Lumie, eureka lemon (Citrus limon), Sambokan (Citrus sulcata), Sudachi (Citrus sudachi) and Koji (Citrus leiocarpa) fruits were found to contain high levels of eriocitrin in both peel and juice vesicles. Copyright © 2006 Society of Chemical Industry     

Scirpusin A,a hydroxystilbene dimer from Xinjiang wine grape,acts as an effective singlet oxygen quencher and DNA damage protector

BACKGROUND: Grapes and red wines are rich sources of phenolic compounds such as anthocyanins, catechins, flavonols and stilbenes, most of which are potent antioxidants showing cardioprotective properties. We first isolated scirpusin A, a hydroxystilbene dimer, from a wine grape of Xinjiang, and studied its antioxidant activity. RESULTS: Reactive oxygen species scavenging effects and the protection against reactive singlet oxygen‐induced DNA damage of scirpusin A have been investigated in our experiments. The concentration of scirpusin A required to inhibit 50% of ¹O₂ generation was 17 µmol L^?1, while addition of scirpusin A at 140 µmol L^?1 caused complete inhibition. Further kinetic study revealed that the reaction of Scirpusin A with singlet oxygen has an extremely high rate constant (k_a = 4.68 × 10⁹ L mol^?1 s^?1). Scirpusin A (140 µmol L^?1) exhibited significant inhibition effects on pBR322 DNA breakage. However, scavenging effects of scirpusin A on superoxide anion O₂^?? and hydroxyl radical ·OH were not potent as the inhibitor rates at a concentration of 1400 µmol L^?1 were 28.83% and 19.5%, respectively. CONCLUSION: The present study shows that scirpusin A is a selective quencher of singlet oxygen and a protector against reactive singlet oxygen‐induced pBR322 DNA damage at very low concentrations. Copyright © 2010 Society of Chemical Industry     

Voltammetric analysis of DL‐α‐tocopherol with a paste electrode

BACKGROUND: A voltammetric study of vitamin E (DL‐ α‐tocopherol) detection using square wave stripping and cyclic voltammetry is discussed in this paper. The working sensor was made by mixing carbon nanotube powder with DNA (double‐stranded calf thymus DNA) and mineral oil. In this electrode, the anodic peak was obtained for ? 0.6 V in a 0.1 mol L^?1 phosphate electrolyte solution. RESULTS: Under optimized stripping conditions, analytical linear working ranges of 0.5–4.0 µg L^?1 and 40.0–160.0 µg L^?1 were obtained. The RSD precision was pegged at 0.105% with seven points using an 80 µg L^?1 spike. The detection limit (S/N) was found to be 0.056 µg L^?1 (1.30 × 10^?10 mol L^?1). CONCLUSION: The developed method was found to be applicable to quality control analysis in the food, pharmaceutical and other manufacturing sectors. Copyright © 2008 Society of Chemical Industry     

Effects of exogenous nitric oxide on contents of soluble sugars and related enzyme activities in 'Feicheng' peach fruit

BACKGROUND: Sugar content is one of the main characteristics related to the quality of fruit. Research confirms that nitric oxide (NO) involves a physiological process and prolongs the storage life of fruit. However, little attention has been paid to the effects of NO on sugar metabolism in fruit during storage. In this study, the effect of different concentrations (0, 10, 30 µmol L^?1) of exogenous NO treatment on sugar content and related enzyme activities in ‘Feicheng’ peach fruit was investigated during storage (0–12 days after harvest) at room temperature (25 °C). RESULTS: Results showed that the decrease of firmness and accumulation of sugar and acid:sugar ratio in peach fruit during storage were significantly inhibited by treatment with 10 µmol L^?1 NO. Treatment with 10 µmol L^?1 NO could promote fructose and glucose metabolism during the first 4 days of storage, and increase the content of sucrose and the activities of sorbitol dehydrogenase, sorbitol oxidase and sucrose phosphate synthase in peach fruit during storage. However, acid invertase activity from 8 to 12 days of storage and neutral invertase activity during the first 4 days of storage were inhibited by treatment with 10 µmol L^?1 NO. At the same time, treatment with 10 µmol L^?1 NO inhibited sucrose synthase (SS) activity in decomposition during storage and SS activity in synthesis from 8 to 12 days of storage. CONCLUSION: Treatment with 10 µmol L^?1 NO had a significant impact on content of soluble sugars and related enzyme activities in ‘Feicheng’ peach fruit during storage (0–12 days) at room temperature (25 °C). Copyright © 2011 Society of Chemical Industry     

Polyphenol oxidase activity of two olive (Olea europaea L.) cultivars as an early criterion of Mn toxicity

BACKGROUND: The time course of polyphenol oxidase (PPO) activity in the leaves of two olive cultivars (Picual and FS‐17) irrigated with nutrient solutions differing in Mn concentration (0, 2 and 1280 µmol L^?1) was studied under hydroponic conditions to determine whether PPO activity could be used as an early criterion of Mn status of olive plants, and to elucidate whether genotypic differences exist between the two olive cultivars studied, concerning the effect of Mn concentration on PPO activity. RESULTS: In all the Mn treatments, PPO activity was greater in Picual than in FS‐17. Under excess Mn (1280 µmol L^?1), PPO activity gradually increased with time, starting from day 30 of the experiment in both cultivars, and this increase preceded the appearance of Mn toxicity symptoms. In contrast, in the other two Mn treatments (0 and 2 µmol L^?1) PPO activity increased and afterwards decreased during the experiment, but the trend was not clear. In the 1280 µmol L^?1 treatment, PPO activity linearly increased (R = 0.8836 for Picual and 0.943 for FS‐17) with the increase of Mn concentration in the leaves of both cultivars. In the 1280 µmol L^?1 Mn treatment, PPO activity was negatively related with Fe and Zn concentrations in the leaves, and positively in the 0 and 2 µmol L^?1 Mn treatments with the Ca, Mg and K concentrations. CONCLUSION: From the differential time course of PPO activity in the three Mn treatments (0, 2 and 1280 µmol L^?1), it is concluded that periodic measurements of PPO activity in the leaves of the olive cultivars Picual and FS‐17 can be used for the early detection of Mn toxicity (before the appearance of symptoms). Copyright © 2010 Society of Chemical Industry     

Use of essential oil from Mentha arvensis L. to control storage moulds and insects in stored chickpea

BACKGROUND: Fungal contamination and Callosobruchus infestation results in qualitative and quantitative losses of chickpea seeds during storage. Most of the synthetic chemicals used as preservatives have adverse effects. Therefore, the antifungal and insecticidal potential of Mentha arvensis essential oil was evaluated to determine whether this could be an eco‐friendly substitute of synthetic preservatives. RESULTS: The stored chickpea seeds were dominated by Aspergillus flavus (46.1%) and 30% isolates among them were found toxigenic. The MIC of Mentha oil against A. flavus was recorded at 400 µL L^?1 and it exhibited broad fungitoxic activity against 14 storage fungi. The oil was found superior to some prevalent synthetic fungicides. Mentha oil showed potent insecticidal activity against Callosobruchus chinensis at different concentrations and exposure times. The oviposition by C. chinensis was completely checked at 10 µL L^?1 while F₁ emergence was completely inhibited at 200 µL L^?1. During in situ experiments, 94.05% protection of the chickpea from C. chinensis by Mentha oil showed superiority over the organophosphate insecticide malathion, where 90.75% protection was recorded. CONCLUSION: The Mentha EO showing potent fungitoxic and insecticidal efficacy and may be recommended as a plant‐based preservative in the management of fungal and insect infestation of chickpea and other pulses during storage. Copyright © 2009 Society of Chemical Industry     

Quality of fresh‐cut purple‐fleshed sweet potatoes after X‐ray irradiation treatment and refrigerated storage

The effect of X‐ray irradiation on the quality of fresh‐cut, refrigerated purple‐fleshed sweet potato (PFSP) cubes was investigated. Packaged sweet potato cubes were treated with 0, 250, 500, 750 or 1000 Gy X‐ray irradiation and stored at 4 ± 1 °C for 14 days. After 14 days, total aerobic bacteria counts were 4.1 and 3.2 log₁₀ CFU g^?1, and mould–yeast counts were 3.3 and 3.0 log₁₀ CFU g^?1 in 750 and 1000 Gy treated samples, respectively. Doses up to 1000 Gy did not affect the firmness, moisture content and anthocyanin content of PFSP cubes throughout storage. PFSP cubes' flesh colour did not change during the first week of storage, but lightness (L*) increased after 14 days. Also, irradiation doses at 750 and 1000 Gy decreased saturation (C*) significantly, producing duller flesh colour than controls. Results indicate that X‐ray irradiation treatment at doses up to 1000 Gy can reduce microbial populations while maintaining the physical quality and anthocyanin content of PFSP cubes up to 14 days of storage.     

Effect of Minimal Processing Conditions on Respiration Rate of Carrots

ABSTRACT: Measurement, analysis, and modeling of respiration rate (RR) of fresh produce are fundamental for the engineering design of MAP. This study investigates the effect of type of cutting (sliced in circular shape, batons in rectangular shape, and shredded into thin strips) on the respiration rate of carrots at different temperatures (4, 8, 12, 16, and 20 °C) with ambient atmosphere. The higher respiration rates were found for shredded carrots and the lowest for whole carrots at all the temperatures tested. The RR increased from 9 ± 1 to 26 ± 3, 10 ± 1 to 53 ± 2, 11 ± 1 to 55 ± 2, and 18 ± 1 to 75 ± 3 mL of O₂ per kilogram hour for whole, sliced, baton, and shredded carrots, respectively, as the temperature increased from 4 to 20 °C. On an average, RO₂ and RCO₂ were increased by 85% and 64%, 100% and 72%, and 151% and 124% for sliced, baton, and shredded carrots, respectively, compared to the RR values of whole carrots. The temperature dependence of RR followed an Arrhenius‐type relationship for all types of carrots, with activation energies in the range of 35 ± 3 to 62 ± 2 kJ/mol. Type of cut was the major factor for both RO₂ and RCO₂, with shredded carrots having the highest rates and whole carrots the lowest. RR of whole carrots did not vary during storage, whereas it increased for cut carrots and especially for shredded carrots. The respiratory quotient (RQ) increased with temperature and did not vary during storage in all types of carrots, except the RQ of whole carrots decreased significantly over time.     

Physicochemical and microbiological description of Caxiri – a cassava and corn alcoholic beverage

Caxiri is a fermented alcoholic beverage made from cassava, corn and sweet potatoes by indigenous people in Brazil. Saccharomyces cerevisiae Rhodotorula mucilaginosa, Lactobacillus fermentum, Bacillus subtilis and L. helveticus were the main microbial species detected. Maltose was the main carbohydrate found (19.12 g L^?1), and lactic acid (15.09 g L^?1) and ethanol (92.16 g L^?1) were also found in high concentrations. Gas chromatography‐flame ionisation detector was used to identify thirteen volatile compounds. Among these volatiles, the higher concentrations were decanoic acid (123.04 μg L^?1) for the acids, diethyl malate (88.32 μg L^?1) for the esters, furfural (109.31 μg L^?1) for the aldehydes, 2‐phenylethanol (1022.76 μg L^?1) for the alcohols and 1,1‐diethoxyethane (226.24 μg L^?1) for the others. This study contributes to increasing knowledge of the microbiota present in the alcoholic fermentation produced from cassava, corn and sweet potatoes.     

Measurement and prediction of the concentration of 1‐methylcyclopropene in treatment chambers containing different packaging materials

BACKGROUND: 1‐methylcyclopropene (1‐MCP) has been shown to suppress ethylene response and extend the post‐harvest shelf life and quality of several fruits and vegetables. In the US and Canada, the label treatment dosage for apples is 1.0 and 0.6 µL L^?1, respectively. It has been demonstrated that wood and corrugated fiberboard materials, commonly found in apple storage facilities, absorb 1‐MCP. Losses of 1‐MCP during the exposure period might compromise the effectiveness of the product. The effects of type of material (corrugated fiberboard and high density polyethylene), relative humidity (50%, 80%, and > 95%), ratios of mass of packaging material (kg) per unit volume (m³) of airspace in a treatment chamber, and initial concentration of 1‐MCP (10 and 20 µL L^?1) on the available concentration of gaseous 1‐methylcyclopropene (1‐MCP) in an enclosed chamber were studied. RESULTS: The concentration of 1‐MCP declined in the presence of the materials tested, but the rate at which 1‐MCP gas was removed from the chamber headspace differed markedly. The average percentage loss for HDPE was between 10 and 12% at all conditions tested, while for corrugated fiberboard it ranged from 12 to 94%. CONCLUSIONS: The concentration of 1‐MCP at any time, t, follows an exponential decay behavior. For corrugated boxes, the rate at which 1‐MCP is removed increased up to 10‐fold as the relative humidity increased from 50 to 80%. The 1‐MCP depletion rate doubled as the ratio of material was increased from 4 to 8 kg of corrugated fiberboard m^?3 air. An increase of initial concentration from 10 to 20 µL L^?1 reduced the rate by half. This trend was also observed for HDPE boxes. Copyright © 2009 Society of Chemical Industry