Shelf Life and Microbial Quality of Fresh-cut Mango Cubes Stored in High CO2 Atmospheres

ABSTRACT: Fresh-cut'Carabao'and'Nam Dokmai'mango cubes were stored in air or in high CO₂ atmospheres (3%, 5%, and 10%) at 5 °C and 13 °C. Freshly sliced'Carabao'mango cubes had a lower respiration rate and total bacterial count and higher L-ascorbic acid content and firmness than'Nam Dokmai'mango cubes. The shelf life of fresh-cut mango, based on browning discoloration and water-soaked appearance, was 6 d at 5 °C and 4 d at 13 °C for'Carabao'and 2 d at 5 °C and less than 1 d at 13 °C for'Nam Dokmai'. High CO₂ atmospheres retarded the development of water-soaked'Carabao'cubes at 5 °C and 13 °C and'Nam Dokmai'cubes at 5 °C. Texture of'Carabao'cubes was enhanced by high CO₂, but ethanol and L-ascorbic acid contents were not affected at 5 °C and 13 °C. Total bacterial count was lower in'Carabao'cubes than in'Nam Dokmai'cubes during storage at both temperatures, and a 10% CO₂ only reduced the bacterial count on'Carabao'and'Nam Dokmai'cubes stored at 13 °C. Bacterial flora in'Nam Dokmai'mango cubes consisted mostly of Gram-negative rods assigned primarily to phytopathogenic bacteria such as Pantoea agglomerans and Burkholderia cepacia . The genera of bacteria isolated from cubes stored in 10% CO₂ were similar to those from cubes on the initial day.     

Low O2 Atmospheres Affect Storage Quality of Zucchini Squash Slices Treated with Calcium

Calcium chloride treated or nontreated zucchini squash slices were stored in air or low O₂ (0.25, 0.5 and 1%) at 10°C. Respiration rate, ethylene production, and development of browning/decay were reduced under low O₂. Slices stored under 0.25% O₂ had less weight loss and browning/decay, and greater shear force and L-ascorbic acid content than those stored in air. Microbial count, pH, and color at the end of storage were improved by low O₂. Calcium treatment had no additive effect on maintaining quality of zucchini squash slices stored in 0.25% O₂ atmosphere.     

Mesophilic Aerobic Population of Fresh-cut Spinach as Affected by Chemical Treatment and Type of Packaging Film

ABSTRACT: Fresh-cut spinach was treated with citric acid and ascorbic acid solutions and packaged in mono-oriented polypropylene bags or low-density polyethylene bags. Response surface methodology was used to study the simultaneous effect of chemical treatment and refrigerated storage time on headspace gas composition, mesophilic aerobic population (AP), and pH of fresh-cut spinach. Type of film affected %CO₂, %O₂, and pH but did not influence AP. Chemical treatment reduced initial pH values and initial microbial counts. AP and pH increased during refrigerated storage. The model developed for AP enabled finding acid concentrations that lowered AP below any proposed microbiological criterion at production and consumption stages of fresh-cut spinach stored at 4 °C.     

Quality of Fresh-cut Apple Slices as Affected by Low-dose Ionizing Radiation and Calcium Ascorbate Treatment

ABSTRACT: Although ionizing radiation effectively inactivates food-borne bacterial pathogens in fresh-cut fruits and vegetables, it may adversely affect product quality. In this study, the effects of calcium ascorbate (CaA) and ionizing radiation on quality of 'Gala' apple slices under modified atmosphere packaging were investigated. 'Gala' apple slices, treated with water or 7% CaA followed by either nonirradiation (0 kGy) or irradiation at 0.5 and 1.0 kGy, were stored at 10°C for up to 3 wk. The titratable acidity, pH, firmness, ascorbic acid content, color, and microflora population were measured weekly throughout storage. Irradiation did not affect titratable acidity and pH of sliced apples. Fruit slices softened during irradiation and storage, but this decrease in firmness during storage was reduced by the CaA treatment. Although the ascorbic acid content of apple slices treated with CaA decreased rapidly during storage, the ascorbic acid content was always higher in those treated samples than in the apple slices treated with water. Irradiation decreased both L * and hue values of apple slices. Hue values decreased during the entire storage period while L * increased during the 1st wk of storage, then decreased between 1 to 3 wk of storage. CaA increased L * and hue values of apple slices, suggesting CaA reduced browning, even in irradiated samples. The microflora population of apples slices was not affected by CaA, and CaA treatment did not alter the reduction in microflora by irradiation. The combination of CaA and irradiation enhanced microbial food safety while maintaining quality of fresh-cut apple slices.     

Changes in the Quality of Fresh-cut Jicama in Relation to Storage Temperatures and Controlled Atmospheres

ABSTRACT: Intact jicama (Pachyrhizus erosus) roots are chilling sensitive, but quality of fresh-cut pieces (1.8 × 4.5 cm cylinders) was best maintained at low storage temperatures (0 to 5 °C). Respiration rates of different piece sizes were similar, and averaged 2, 7 and 10 μL CO₂-g ⁻¹h⁻¹ at 0 °C, 5 °C and 10 °C, respectively. Storage in air at 5 °C to 10 °C resulted in surface browning and was associated with increases in phenolics and phenylalanine ammonia lyase and polyphenol oxidase activities. High CO₂ atmospheres (5 to 10%) at 5 °C were very effective in retarding microbial growth and discoloration. The source of jicama root notably affected the quality and shelf-life of the fresh-cut pieces. Fresh-cut pieces from stored roots (2 wk at 19 to 22 °C) had lower visual quality and crispness during subsequent storage than did pieces from recently harvested roots.     

热水处理对鲜切马铃薯生理和品质的影响

以鲜切马铃薯为试验材料,研究鲜切马铃薯在35℃10 min的热水处理和对照组(CK)下生理指标和品质指标的变化。结果表明:在低温(4℃)贮藏条件下,35℃10 min的热水处理显著抑制了鲜切马铃薯的失重率和呼吸强度,维持了较高的白度和可溶性固形物含量,有效地保持了细胞膜的完整性,抑制了多酚氧化酶(PPO)和过氧化物酶(POD)的活性,从而改善了鲜切马铃薯的贮藏品质,延缓了鲜切马铃薯的褐变。     

Mathematical modelling of O2 consumption and CO2 production rates of whole mushrooms accounting for the effect of temperature and gas composition

Investigation of respiration rate of fresh produce, under different gas composition and temperatures, and respective mathematical modelling is central for the modified atmosphere packaging design. This work investigates the effect of temperature (4, 8, 12, 16, 20 °C) and gas composition (O₂ between 3 to 21% and CO₂ between 0 to 15%) on respiration rate of whole mushrooms. Oxygen and carbon dioxide respiration rates increased significantly (3–4 fold) as the temperature elevated from 4 to 20 °C and were in the range of 13.23 ± 3.12 to 102.41 ± 2.132 mL kg⁻¹ h⁻¹) and 14.33 ± 1.56 to 97.02 ± 2.51 mL kg⁻¹ h⁻¹) respectively. Low O₂ and high CO₂ levels reduced O₂ consumption and CO₂ production rates of whole mushrooms on average by a circa 47–60% at all temperatures as compared to the respiration rate at ambient air. Mathematical models were developed for RO₂ and RCO₂, by combining the Arrhenius and Michaelis–Menten uncompetitive equations. These models predicted well, O₂ consumption and CO₂ production rates of whole mushrooms as a function of both temperature and gas composition.     

高氧气调包装对鲜切莴苣呼吸和酶活性的影响

以空气包装的鲜切莴苣为对照,研究了60%O2﹢20%CO2﹢20%N2和100%O2高氧气调包装的鲜切莴苣在4℃贮藏14d期间呼吸强度和酶活性的变化。结果表明:高氧气调包装对鲜切莴苣呼吸和酶活性影响显著,60%O2﹢20%CO2﹢20%N2和100%O2高氧气调包装显著抑制鲜切莴苣的呼吸,且100%O2气调包装的抑制效果优于60%O2﹢20%CO2﹢20%N2气调包装;60%O2﹢20%CO2﹢20%N2和100%O2高氧气调包装促进SOD酶活性的上升、抑制O2-.生成量的增加和PPO、PAL酶活性的上升。     

Quality Changes in Fresh-cut Peach and Nectarine Slices as Affected by Cultivar, Storage Atmosphere and Chemical Treatments

The shelf-life of slices from 13 cultivars of peaches and 8 cultivars of nectarines, varied (between 2 and 12 days at 0°C). Controlled atmospheres of 0.25 kPa O₂ and/or 10 kPa or 20 kPa CO₂ extended the shelf-life at 10°C of ‘O'Henry’ or ‘Elegant Lady’ peach slices by 1–2 days beyond the air control. Low (0.25 kPa) O₂ acted synergistically with CO₂ levels of 10 and 20 kPa to induce fermentative metabolism as indicated by ethanol and acetaldehyde production. A 2% (w/v) ascorbic acid + 1% (w/v) calcium lactate postcutting dip resulted in limited reduction of cut surface browning and tissue softening in ‘Carnival’ peach slices.     

Sensory, Microbiological and Chemical Quality of Mini-Peeled Carrots as Affected by Edible Coating Treatment

The effect of three application rates of an edible cellulose-based coating on sensory, microbiological and chemical quality of mini-peeled carrots was studied during storage at 2°C. Carrots treated with edible coating had reduced levels of white surface discoloration, and higher sensory scores for orange color intensity, fresh carrot aroma, fresh carrot flavor, and overall acceptability than non-coated carrots. Edible coating treatment did not affect levels of total aerobic microorganisms, yeast, mold or lactobacilli. Oxygen, carbon dioxide and ethanol levels in packages, and sugar and soluble phenolic content of mini-peeled carrots were not affected by coating treatment. An edible coating application rate of 0.23–0.49 L/min protected against surface discoloration and retained quality during storage at 2°C.     

Fruit Quality, Antioxidant Contents and Activity, and Antiproliferative Activity of Strawberry Fruit Stored in Elevated CO2 Atmospheres

ABSTRACT:  The effects of CO₂ in the storage atmosphere on color, firmness, ascorbic acid (AA), anthocyanins, flavonoids, phenolics, total antioxidant activity, and antiproliferative activity of strawberry fruit have been investigated. "Northeaster" and "Earliglow" strawberries were stored in air or in 20% CO₂ (in air) at 3 °C for 20 d. Color changes in Northeaster were delayed more by CO₂ treatment than in Earliglow. Firmness of CO₂-stored fruit increased slightly compared with those stored in air. The increases in total and reduced AA concentrations during air storage were usually prevented by CO₂ storage in both cultivars. Dehydroascorbic acid (DHA) concentrations increased during CO₂ storage. Anthocyanins and flavonoids, and total antioxidant activity of both cultivars were higher in air-stored fruit than in CO₂-stored fruit. The total phenolic concentration was lower in CO₂-stored Earliglow fruit than in air, but storage treatment did not affect that of Northeaster. A 40 mg/mL concentration of Northeaster strawberry extract inhibited about 80% of HepG₂ human liver cancer cell proliferation. CO₂ treatment did not affect the antiproliferative activity of strawberry fruits, but antiproliferative activity was greater at harvest than after storage.     

Quality Changes in Fresh-cut Pear Slices as Affected by Cultivar, Ripeness Stage, Fruit Size, and Storage Regime

Fresh-cut fruit slices prepared from partially ripened Bartlett pears had longer shelf life than those from Bosc, Anjou, and Red Anjou pears. Pear fruit ripeness, based on flesh firmness of 44 to 58 N, is optimal for fresh-cut pear slice processing. Pear slices derived from smaller size fruit (122 to 135 g) have greater cut surface discoloration and deteriorate more rapidly than slices derived from larger fruit (152 g). Recently harvested Bartlett pear fruit and whole pears held at –1 °C in a controlled atmosphere of 2%O₂+ 98%N₂ had a longer post-cutting shelf life than those held in air at –1 °C for the same duration. Cut surface browning, flesh softening, and surface dehydration of the slice cut surface were all contributors to loss of product quality.     

异抗坏血酸与氯化钙联合处理对鲜切芒果的保鲜效果

为研究异抗坏血酸与氯化钙联合处理对鲜切芒果保鲜效果的影响,鲜切芒果在1 g/100 mL异抗坏血酸和0.5 g/100 mL氯化钙的混合溶液中浸渍处理5 min后,4℃相对湿度80%条件下贮藏15 d,每天取样测定呼吸速率,每3 d测定细胞膜相对渗透率、硬度、可滴定酸、类胡萝卜素、抗坏血酸(AsA)、总酚、褐变指数、超氧阴离子(O₂^-·)产生速率、抗氧化酶及多酚氧化酶(PPO)活性等指标。结果表明:与对照相比,异抗坏血酸+氯化钙联合处理使鲜切芒果的呼吸峰值降低了41.20%,并延缓相对渗透率升高和硬度下降;保持较高的类胡萝卜素、AsA含量,维持总酚含量相对稳定,在贮藏前期保持了较高的可滴定酸含量,减少褐变发生;降低了O₂^-·产生速率,明显抑制PPO的活性,提高超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性,并且在0~9 d时延缓过氧化物酶(POD)的下降,但在贮藏后期降低了POD的活性。以上结果表明异抗坏血酸+氯化钙联合处理可以保持鲜切芒果较好的贮藏品质,延缓膜透性增加并提高活性氧(ROS)的清除能力,从而延缓衰老,抑制褐变。     

Effects of Short-term Exposure to Low O2 and High CO2 Atmospheres on Quality Attributes of Strawberries

Strawberries (Fragaria ananassa Duch., cv. ‘Selva') were stored 10 days in 1.0%, 0.5%, or 0.25% 0₂ or air + 20% CO₂; or 6 days in air + 50% or 80% CO₂ at 0 or 5°C without detrimental effects on quality. Decay and softening were reduced by treatments. An untrained taste panel, under ordinary eating conditions, did not consistently differentiate ‘Pajaro’ strawberries kept in 0.25% 0₂ from those stored in air. A trained taste panel, under controlled conditions, perceived slight off-flavor in ‘G3’ strawberries kept in 0.25% or 0% 0₂. This correlated with ethanol, ethyl acetate, and acetaldehyde in juice. The 50% or 80% CO₂ treatments caused injury after 8 to 10 days, while 20% CO₂ treatments did not. All high CO₂ treatments caused increase in pH of juice.     

模拟运输时间对芒果低温贮藏过程中生理与品质的影响

为探究不同运输时间对芒果后期低温贮藏过程中生理与品质的影响,依托振动台对芒果在转速180 r/min下分别进行12、24、36 h的模拟运输实验,研究运输后芒果在13℃下贮藏20 d的过程中,水分分布、自由水含量、失重率、可滴定酸含量、维生素C含量、呼吸强度、果胶酯酶(PME)含量、多聚半乳糖醛酸酶(PG)含量的变化。结果表明,运输振动使芒果出现了不同程度的瘀伤现象,加速了芒果水分的流失,显著提高了失水率和呼吸峰值,PME和PG含量保持在较高水平,可滴定酸与维生素C损失更多。模拟运输时间越长,对芒果生理与品质的影响也越大。运输中的振动会使芒果代谢加快,加速贮藏过程的品质下降,模拟运输时间24 h及以下的运输组对芒果的损伤在可接受范围,而36 h运输组则对芒果产生了更多的不可逆伤害。     

Quality Index, Consumer Acceptability, Bioactive Compounds, and Antioxidant Activity of Fresh-Cut "Ataulfo" Mangoes (Mangifera Indica L.) as Affected by Low-Temperature Storage

ABSTRACT:  To measure bioactive compound losses due to minimal processing, mature green fresh-cut mangoes ( Mangifera indica L.) cv. "Ataulfo" were subjected to an antioxidant treatment and stored at 5 °C during 15 d. Quality index, total phenols, flavonoids, β-carotene, ascorbic acid, vitamin E, and antioxidant activity were measured during the storage period of fruits. Antioxidant capacity was estimated using ORAC_FL, TEAC, and DPPH assays. The dipping treatments with ascorbic acid (AA) + citric acid (CA) + CaCl₂ affected positively quality delaying deterioration of fresh-cut mango as compared with whole fruit. However, dipping treatment affected the consumer preferences of fresh-cut mangoes. The highest vitamin C, β-carotene, and vitamin E losses were observed after 10 d, being similar in whole and fresh-cut mangoes. The antioxidant activity was not significantly affected by storage time. We conclude that fresh-cut mangoes retained their bioactive compound content during storage and their antioxidant and nutritional properties make them a good source of these compounds.     

Static, Controlled (CO2) Atmosphere Packaging of Retail Ready Pork

Wrapped boneless pork loin roasts and slices were stored at 4°in bulk under constant CO₂ concentrations of 50% and 100% for 1 and 2 wks. Samples stored under 50% CO₂ for 2 wks could subsequently be displayed (aerobic) for 3 days without becoming unacceptable or for 6 days if previously held under 100% CO₂ for 14 days. Aerobic shelf-life at 4°of the latter samples equalled that of fresh pork chops under simulated retail display. Physicochemical characteristics during storage did not limit acceptability. Reusable master packs have application for distribution of retail ready cuts under controlled atmosphere packaging.     

Modeling of O2and CO2 Exchange Dynamics in Modified Atmosphere Packaging of Burlat Cherries

ABSTRACT: A simple mathematical model has been applied to estimate the optimal conditions for modified atmosphere packaging (MAP) of Burlat cherries. The model describes gas exchange in flexible packages, taking into account the respiration rate of the fruit and the transmission rate of gases through the film. The model predicts the evolution of the gas composition inside the package at different conditions. To verify experimentally the model estimations, Burlat cherries were packaged in air and in 3 mixtures of gases at 2 temperatures using 3 different films. Experimental results agree satisfactorily with the predicted values if the O₂ concentration is higher than 2 %.     

Atmospheric Composition and Quality of Fresh Mushrooms in Modified Atmosphere Packages As Affected by Storage Temperature Abuse

Mushrooms (Agaricus bisporus) were packaged in 4-liter modified atmosphere (MA) containers, and a steady-state atmosphere of 5% and 10% was maintained at 4 °C. Temperature was fluctuated from 4 °C to 20 °C during 12-d storage period in cycles: 2 d at 4 °C followed by 2 d at 20 °C. Temperature increase during fluctuations caused anoxic atmospheres both in O₂ (1.5%) and CO₂ (22% to 10%). The quality of mushrooms stored under temperature fluctuating regime was severely affected as indicated by extensive browning, loss of firmness, and the level of ethanol in the tissue compared to mushrooms stored at constant temperature. It was clear that temperature fluctuation, even if it should occur once, can seriously compromise the benefits of MA packaging and safety of the packaged produce.     

Postharvest CO2 and Ethylene Production and Quality Maintenance of Fresh-Cut Kiwifruit Slices

The quality attributes and gas production of fresh-cut kiwifruit slices (Actinidia deliciosa cv. Hayward) were studied to identify the optimum ranges of storage temperature, relative humidity, and atmospheric composition. Also the effects of wounding, C₂H₄ addition or removal, and chemical treatments (calcium, ascorbic acid, citric acid) on deterioration rate were investigated. Flesh softening was the major quality loss of stored fresh-cut kiwifruit slices. Fresh-cut kiwifruit slices had a shelf-life of 9–12 days if treated with 1% CaCl₂ or 2% Ca lactate, and stored atO-2°C and >90% relative humidity in an C₂H₄-free atmosphere of 2 to 4 kPa O₂ and/or 5to10kPaCO₂.