Atmosphere Packaging Research Articles

Effects of Temperature and Packaging Atmosphere on Shelf Life, Biochemical, and Sensory Attributes of Glasswort (Salicornia europaea L.) Grown Hydroponically at Different Salinity Levels.

Halophytes, such as Salicornia species, are promising new foods and are consumed for their pleasant salty taste and nutritional value. Since Salicornia is perishable, modified atmospheric packaging (MAP) can be a useful tool, in combination with proper temperature, to halt further quality degradation in this type of product. The purpose of this study was to investigate the effect of MAP, with or without refrigeration, to extend the shelf life of glasswort (Salicornia europaea L.) grown hydroponically (floating raft system) in a greenhouse with a nutrient solution containing 0 g/L (C) or 12.5 g/L of NaCl (T). The dry matter content, weight loss, respiration rate, biochemical composition, color, antioxidant capacity, and sensorial attributes were determined in shoots after harvest and during storage in plastic bags filled with technical air or with MAP at 4 or 20 °C for 120 h. At harvest, plants supplied with salt-enriched solution (T) showed a significant improvement in nutritional value and sensory profile. Storage in air at room temperature (20 °C) accelerated weight loss and diminished color stability, particularly in non-salinity samples (C), while MAP extended the shelf life of all the samples regardless of the storage temperature adopted. Optimal storage conditions were observed when MAP was combined with refrigeration, which allowed to effectively preserve shoots sensory acceptability for a period of about seven days. Future research could further explore the long-term effects on the nutritional value and sensory quality of S. europaea under various combinations of MAP and different storage temperatures ranging between 4 °C and 20 °C.

Growth of Listeria monocytogenes in fresh vegetables and vegetable salad products: An update on influencing intrinsic and extrinsic factors.

The ability of foodborne pathogens to grow in food products increases the associated food safety risks. Listeria monocytogenes(Lm) is a highly adaptable pathogen that can survive and grow under a wide range of environmental circumstances, including otherwise inhibitory conditions, such as restrictive cold temperatures. It can also survive long periods under adverse environmental conditions. This review examines the experimental evidence available for the survival and growth of Lm on fresh vegetables and ready-to-eat vegetable salads. Published data indicate that, depending on certain intrinsic (e.g., nutrient composition) and extrinsic factors (e.g., storage temperature, packaging atmosphere), Lm can survive on and in a wide variety of vegetables and fresh-cut minimally processed vegetable salads. Studies have shown that temperature, modified atmosphere packaging, relative humidity, pH, water activity, background microbiota of vegetables, microbial strain peculiarities, and nutrient type and availability can significantly impact the fate of Lm in vegetables and vegetable salads. The influence of these factors can either promote its growth or decline. For example, some studies have shown that background microbiota inhibit the growth of Lm in vegetables and minimally processed vegetable salads, but others have reported a promoting, neutral, or insignificant effect on the growth of Lm. A review of relevant literature also indicated that the impact of most influencing factors is related to or interacts with other intrinsic or extrinsic factors. This literature synthesis contributes to the body of knowledge on possible strategies for improving food safety measures to minimize the risk of Lm-associated foodborne outbreaks involving vegetables and vegetable salads.

Enhancing High-Pressure Bacterial Inactivation by Modified Atmosphere Packaging: Effect of Exposure Time and Cooked Ham Formulation

AbstractHigh-pressure processing (HPP) is a non-thermal preservation technology that can be applied as a control measure to inactivate pathogens and spoilage microorganisms once RTE meat products are packaged in a convenient format. HPP efficacy highly depends on product characteristics, but the impact of the sodium-reduced formulations and the effect of packaging atmosphere are scarcely known. The aim of the present work was to assess the effect of standard and sodium-reduced formulations from two different brands (A, B) under different packaging (vacuum and modified atmosphere packaging (MAP)) on the HPP inactivation kinetics of Listeria monocytogenes and spoilage lactic acid bacteria in cooked ham. Slices of cooked ham with standard and sodium-reduced formulations were inoculated with L. monocytogenes CTC1034 and Latilactobacillus sakei CTC746 (slime producer), packaged in vacuum and MAP (CO2:N2, 20:80), and pressurized (400 MPa/0–15 min) after 1 h (vacuum, MAP) or 24 h (MAP-exposed). Parameters of HPP inactivation kinetics were estimated by fitting the Weibull model to log reduction data. Results showed that the efficacy of HPP in sodium-reduced cooked hams tended to decrease compared to standard formulations, being the difference statistically significant for L. sakei. For L. monocytogenes, a significant enhancing effect of MAP was observed when HPP was applied just after packaging (1 h, MAP) of cooked ham of brand A. In the case of L. sakei, the inactivation by HPP was only enhanced in MAP-exposed samples. Therefore, the use of HPP as a control measure must be applied through a product-oriented approach considering the type of packaging and the time period between packaging and HPP.

Impact of Different Technologies and Methods to Increase the Shelf Life and Maintain the Sulforaphane Content in Broccoli: A Review

Broccoli, a nutrient-rich vegetable known for its sulforaphane content and health benefits, faces challenges related to its short shelf life and susceptibility to spoilage. This study explores various techniques to maintain sulforaphane content and extend broccoli's shelf life. Freezing, although effective for long-term preservation, involves blanching that inactivates myrosinase, preventing sulforaphane formation. Cold storage at 4-5°C slows respiration and senescence, extending shelf life up to 14 days while preserving bioactive compounds. Modified atmosphere packaging (MAP) enhances shelf life by altering the package atmosphere, with active packaging using 15% CO2 and 7.5% O2 at 0°C proving particularly effective in reducing bacterial growth and preserving quality. Light exposure, especially with yellow LED lights and moderate UV treatment, retains high levels of glucosinolates and phenolic compounds. Irradiation effectively eliminates pathogens and preserves visual quality, with gamma irradiation slowing the oxidation of phenols and ascorbic acid, although further research is needed on its sensory and nutritional effects. High-pressure processing (HPP), a non-thermal method, significantly boosts sulforaphane bioactivity by converting glucosinolates at pressures up to 600 MPa, despite challenges such as high costs and operational safety, and prevents microbial growth, extending shelf life while maintaining nutritional quality. Additionally, techniques like steaming for optimal durations, microwaving at high power for short times, and stir-frying help preserve sulforaphane content during cooking. Preharvest chemical treatments like chitosan and calcium also enhance broccoli's defence mechanisms and bioactive compound levels. Overall, these methods offer a comprehensive approach to preserving sulforaphane content and extending broccoli's shelf life, providing valuable insights to enhance the storage, quality, and health benefits of broccoli for consumers.

Impact of packaging atmosphere, oregano essential oil, and storage temperature on cold-adapted Salmonella Enteritidis and Salmonella Typhimurium on ready-to-eat smoked turkey

The hazard of diseases created by S. Enteritidis and S. Typhimurium is relatively high in turkey meat products. Combinations of preservation methods are utilized in many strategies, such as mild heat with decreased water activity, a changed atmosphere, refrigerated storage, and decreased heat treatment with some acidification. Within the domain of ready-to-eat food technology, a range of preservation methods are typically utilized to enhance shelf life, such as applying mild heat in tandem with reduced water activity, employing modified atmosphere packaging, utilizing refrigerated storage, and utilizing reduced heat treatment combined with acidification. This investigation aimed to determine how S. Enteritidis and S. Typhimurium grew when sliced ready-to-eat smoked turkey (RTE-SM) was stored at 0, 5, 10, and 15°C for various periods. The study also examined the effects of modified atmosphere packaging (MAP) (40% CO2 and 60% N2) and VP on these growth patterns. Total viable count (TVC), lactic acid bacteria (LAB), pH, and redox potential levels were determined. The control experiment on RTE-SM showed no Salmonella growth within 30 days of storage at any temperature. This indicated that the RTE-SM in use did not initially contain S. Typhimurium and S. Enteritidis. Results indicated that the storage of RTE-SM using a combination of VP, MAP, and MAPEO with storage at 0 and 5°C did not allow for the pathogen to grow throughout storage. In comparison, at 10 and 15°C after one day, which allowed for minor growth (0.17-0.5 log CFU/g)? In contrast, at 0 and 5°C, Salmonella survives until the end of storage (173 days). However, the combination of MAPEO with the same storage temperatures achieved the elimination of the pathogen in the meat after 80 days. The combination of both packaging systems with high temperatures (10 or 15°C) allowed for the multiplication and growth of the bacterium through the product's shelf life of more than 1 log CFU/g. Thus, a combination of MAP or MAPEO with low storage temperatures (0 or 5°C) inhibited the growth of the pathogen.

Rapid and non-destructive microbial quality prediction of fresh pork stored under modified atmospheres by using selected-ion flow-tube mass spectrometry and machine learning

Volatile organic compounds (VOCs) indicative of pork microbial spoilage can be quantified rapidly at trace levels using selected-ion flow-tube mass spectrometry (SIFT-MS). Packaging atmosphere is one of the factors influencing VOC production patterns during storage. On this basis, machine learning would help to process complex volatolomic data and predict pork microbial quality efficiently. This study focused on (1) investigating model generalizability based on different nested cross-validation settings, and (2) comparing the predictive power and feature importance of nine algorithms, including Artificial Neural Network (ANN), k-Nearest Neighbors, Support Vector Regression, Decision Tree, Partial Least Squares Regression, and four ensemble learning models. The datasets used contain 37 VOCs' concentrations (input) and total plate counts (TPC, output) of 350 pork samples with different storage times, including 225 pork loin samples stored under three high-O2 and three low-O2 conditions, and 125 commercially packaged products. An appropriate choice of cross-validation strategies resulted in trustworthy and relevant predictions. When trained on all possible selections of two high-O2 and two low-O2 conditions, ANNs produced satisfactory TPC predictions of unseen test scenarios (one high-O2 condition, one low-O2 condition, and the commercial products). ANN-based bagging outperformed other employed models, when TPC exceeded ca. 6 log CFU/g. VOCs including benzaldehyde, 3-methyl-1-butanol, ethanol and methyl mercaptan were identified with high feature importance. This elaborated case study illustrates great prospects of real-time detection techniques and machine learning in meat quality prediction. Further investigations on handling low VOC levels would enhance the model performance and decision making in commercial meat quality control.

Valorization of fish from the Adriatic Sea: nutritional properties and shelf life prolongation of Aphia minuta through essential oils.

This study aimed to exploit the nutritional and microbiological qualities of Aphia minuta, which are still largely unknown; they are collected from Golfo di Manfredonia (Adriatic Sea). Chemical composition, fatty acids, and amino acid profiles were evaluated during winter, spring, and summer (two samples each season). The protein content was highest in spring, while no significant differences were found for fat and ash contents across all sampling periods. Fatty acid profile analyses revealed that monounsaturated and polyunsaturated fatty acids were affected by the sampling season. Notably, the value of n-3 polyunsaturated fatty acids increased in spring and summer compared to the winter season. The highest content of essential amino acids was measured during the spring and summer seasons (P < 0.01), with leucine and lysine being the most dominant. Regardless of the fishing season, from a nutritional point of view, this species is an excellent source of bioactive compounds. This study also focused on the microbiological quality and shelf life of Aphia minuta. Initially, the bioactivity of three different essential oils (thymol, lemon, and citrus extract) was tested on Pseudomonas fluorescens, Staphylococcus aureus, and Escherichia coli. These essential oils were then combined with various packaging materials (conventional, maize starch, and polylactate) and packaging atmosphere (air, vacuum, and a modified atmosphere with reduced oxygen content). The results indicated that combining citrus extract with vacuum packaging significantly reduced the psychrotrophic viable count to undetectable levels after 7 days. This study suggests some important considerations for exploiting and expanding the market of the Aphia minuta.

Optimising package perforation and headspace gas atmosphere in carrot packages stored under chilled and abused temperature conditions

Optimising package perforation and headspace gas atmosphere in carrot packages stored under chilled and abused temperature conditions

The Relationship Between Class Climate And Citizen’ Participation In Learning Equality Package B in SPNF-SKB Region II Padang City

The background to this research is the low participation of residents in the package B equality learning program at SPNF-SKB Region II Padang City. One of the suspected causes is that classroom conditions are less conducive for residents taking part in the program. The aim of this research is to see an overview of the classroom climate in package B equality learning at SPNF-SKB Region II Padang City. We also want to see a picture of student participation in package B equality. Apart from that, we want to know the relationship between classroom climate and learning participation in package B equality in SPNF-SKB Region II Padang City. In this research, a quantitative approach was used to carry out correlational analysis. In this research, the population studied was 72 people who were citizens studying package B equality in SPNF-SKB Region II Padang City. At the same time, the sampling technique used was stratified random sampling with a proportion of 50% (36). Data collection technique employs the distribution of questionnaires directly to the respondents. Percentage and product moment formulas are used in data analysis techniques. From the research conducted, it was found that the classroom conditions of students who used package B in studying equality were classified as unsupportive, and citizen participation in studying equality in package B tended to be low. Apart from that, there is a significant relationship between class conditions and student participation in package B equality learning at SPNF-SKB Region II Padang City. Tutor research findings suggest that the class atmosphere in Package B learning can be improved.Keywords: Clasroom Clite,, Participation, Learning Cittiziens

Effects of Electron Beam Sterilization on Polytetrafluoroethylene: Design of Experiments Study.

Polytetrafluoroethylene (PTFE) is a common polymer used in medical devices due to its exceptional properties (e.g., biocompatibility, inertness, chemical stability, low coefficient of friction). However, as a result of molecular weight reduction caused by the process of chain scission, it is known to be susceptible to radiation exposure and can rapidly lose strength and integrity. In this design of experiments study, the goal was to determine whether an operating window of conditions exist for electron beam (E-beam) radiation sterilization in which the degradation of PTFE is acceptably low. PTFE was tested for yield stress after exposure to radiation under different parameters (total dose [15-60 kGy], packaging atmosphere [air/nitrogen], and poststerilization accelerated aging [real-time equivalent of 1 and 3 years]). The results showed that total dose and packaging atmosphere were significant factors and indicated that the use of modified atmosphere packaging (vacuum sealing with nitrogen gas purge) can be a useful approach in increasing the stability of PTFE toward E-beam sterilization.

The pro-oxidant action of high-oxygen MAP on beef patties can be counterbalanced by antioxidant compounds from common hawthorn and rose hips

The objective of this research was to evaluate the effectiveness of antioxidant-rich extracts from rose hip (Rosa canina L.; RC) and hawthorn (Crataegus monogyna Jacq.; CM) at minimizing the oxidative damage to proteins and lipids in beef patties subjected to a high‑oxygen (HiOx-MAP) and vacuum (Vacuum) packaging atmosphere. The extracts of RC and CM were characterized by quantifying bioactive compounds, namely, phenolic compounds, tocopherols and vitamin C. Both fruits had high concentrations of bioactive compounds, with RC having the highest total phenolic and vitamin C content. Yet, CM was the most efficient in protecting beef patties against protein carbonylation, reducing, as a result, the instrumental toughness in cooked beef patties. The use of CM and RC extracts in beef patties significantly improved consumer purchase intention in HiOx-MAP packaging systems. The use of CM and RC extracts or their combination in future research would be an effective antioxidant means to decrease the pro-oxidative effects caused by HiOx-MAP in red meat.

Quality assessment of cold dried chicken slices during storage in different packages and temperatures

In this study, dried chicken slices were packaged in MAP (modified atmosphere packaging) and AP (atmospheric packaging), and stored at 4 °C and 25 °C. The CO2 content of MAP packaged samples decreased as the storage temperature and time increased. The slices exhibited lower aw values when they were packaged in AP at 25 °C. The pH increased from 6.1 to 6.2, 2-thiobarbituric acid reactive substances (TBARS) increased from 10.6 to 37.3 µmol MDA kg-1, and non-protein nitrogen (NPN) increased from 4.9 to 5.3 g 100 g-1 in MAP for 90 days of storage. The microbiological quality of the samples was assessed by enumerating total aerobic mesophilic bacteria (TAMB), total psychrophilic bacteria (TPB), Micrococcus/ Staphylococcus, lactic acid bacteria (LAB), Enterobacteriaceae and yeast-mold, and was higher in the sample stored in MAP at 4 °C. Moreover, the sensory quality was determined by sensory evaluation with a 9-point hedonic scale. When the sensory and microbiological qualities were evaluated together, the shelf lives of the samples were determined to be 90 days at 4 °C and 75 days at 25 °C for MAP and 45 days at 4 °C and 30 days at 25 °C for AP. It could be concluded that the cold dried chicken slices can be stored in MAP for 90 days without much change in physicochemical, microbiological, and sensory quality.

Screening of volatile organic compounds emitted from different packaging materials: case study on fresh-cut artichokes

In the present work, the emission of volatile organic compounds (VOCs) from plastic packaging materials and their migration to the packaged product was investigated. Fresh-cut artichokes were chosen as a case study owing to their nutritional profile, including phenolic compounds, antioxidants, inulin and fiber, and the high market demand. Artichokes were cut into quarters, packaged in active modified atmosphere (5% O2 and 10% CO2) in three different micro-perforated (MP) packages (polypropylene (PP), polypropylene/polyamide (PP/PA) and polylactic acid (PLA)) and stored for 10 days at 5° C. For the detection of VOCs on the packaging materials and in the packaged product, three approaches were considered. First, VOCs emitted from a piece of package were extracted by solid phase micro extraction (SPME), at 30°C, and analyzed by gas-chromatography coupled to mass spectrometry (GC–MS). Second, VOCs from the headspace of the empty closed bag were extracted by SPME, at 5°C, to understand if any packaging volatile compound was transferred into the package atmosphere in this temperature condition. Finally, packaged artichokes were also analyzed by SPME/GC–MS to detect any presence of packaging volatiles compared to the fresh product. Emitted VOCs were different according to the material; in particular PP/PA emitted the greatest number of VOCs, most of them belonging to the class of branched alkanes and alkenes, such as 4-methyl-heptane, 2,4-dimethyl-heptane, 4-methyl-octane and 2,4 dimethyl heptene; PP emitted octane, aldehydes, and 1-metoxy-2-propanol; PLA emitted aldehydes and propanoic acid. Some VOCs were found into the atmosphere of the empty bags as well as on packaged artichokes, while they were not found in the fresh samples before packaging, suggesting that a study on the emission of VOCs from different plastic materials in contact with food and on the effect of different storage conditions is very critical for a better understanding of this issue.

Selected-ion flow-tube mass spectrometry for the identification of volatile spoilage markers for fresh pork packaged under modified atmospheres

Microbial behavior during meat storage leads to the generation of volatile organic compounds (VOCs) and unpleasant off-odors. This study focused on a novel real-time analytical method, selected-ion flow-tube mass spectrometry (SIFT-MS), to monitor VOC quality and identify spoilage indicators for fresh pork stored under different packaging atmospheres (air, 70/0/30, 70/30/0, 5/30/65, 0/30/70 – v/v% O2/CO2/N2) at 4 °C. A comprehensive selection methodology was used to identify compounds with good instrumental data quality as well as a strong relationship with microbial growth and olfactory rejection. Based on the volatolome quantified by SIFT-MS, storage periods and conditions can be discriminated using multivariate statistics. Acetoin (or ethyl acetate) represented a significant pork quality marker for high-O2 conditions, whereas ethanol, 3-methylbutanal and sulfur compounds can indicate the anaerobic storage progress. Considering the applicability in monitoring different VOC profiles, SIFT-MS is expected to be promising in many storage scenarios to improve analytical efficiency and ensure reliability.

Optimization of Modified Atmosphere Packaging for Sheep’s Milk Semi-Hard Cheese Wedges during Refrigerated Storage: Physicochemical and Sensory Properties

Modified atmosphere packaging (MAP) has become a good potential strategy to retain quality throughout the shelf life of perishable foods. The aim of this work was to evaluate different packaging atmospheres on semi-hard protected designation of origin Idiazabal cheese wedges. Six different packaging treatments (air, vacuum, and CO2/N2 gas mixtures in the ratio of 20/80, 50/50, 80/20, and 100/0% v/v, respectively) were studied. Changes in gas headspace composition, cheese gross composition, weight loss, pH, acidity, colour, and textural and sensory properties were investigated during 56 days of refrigerated storage at 5 ± 1 °C. MAP was the most effective preserving technique compared to air- and vacuum-packaging treatments. The cheese characteristics with the greatest discriminating weight in the preservation techniques were paste appearance, holes, flavour, a* (redness) and b* (yellowness) colour parameters, and slope to hardness. Air-packaged cheeses, on 35 day, presented a mouldy flavour. Vacuum packaging affected paste appearance (greasy, plastic marks, and non-homogeneous colour) and holes (occluded and unnatural appearance) starting after 14 packaging days. MAP mixtures with CO2 concentration between 50/50 and 80/20% CO2/N2 (v/v) are recommended to ensure sensory quality and stability in the distribution of these raw sheep-milk cheese wedges.

Embalagens de sementes de soja armazenadas em diferentes ambientes

Abstract The objective of this work was to evaluate packaging for preserving the quality of soybean (Glycine max) seeds stored in different environments. The experiment design was completely randomized, in a factorial arrangment with six seed storage conditions: natural atmosphere (NA), laminated packaging atmosphere (LPA), modified atmosphere in polyethylene packaging (MAPP), refrigerated atmosphere in raffia packaging (RARP), refrigerated atmosphere in laminated packaging (RALP), and modified and refrigerated atmosphere in polyethylene packaging (MRAPP), with four storage times (zero, two, four, and six months). Storage time reduces the quality of soybean seeds after two months in all tested packaging. The germination of the soybean seeds was maintained in the following packaging: LPA, RARP, RALP, and MRAPP. LPA is the most efficient packaging for soybean seeds, which show the highest percentage of germination for the longest storage time, without requiring any modification or refrigeration of the atmospheric storage environment.

Intra- and inter-batch variability in raw pork challenge test studies and their consequences on model predictions: An intricate interplay between L. monocytogenes, the microbiome, and packaging atmosphere

The purpose of this study was to conduct challenge studies in raw pork by strictly following all aspects of the 2014 EURL technical guidance document for conducting shelf-life studies on Listeria monocytogenes. Growth potential was assessed on three batches of self-cut pork chops and one batch of in-house prepared pure minced pork without any additives in air and MAP (70 % O2/30% CO2) packaging. Pork chops did not support the growth of the pathogen throughout the shelf-life, given the specific conditions used in this study, with growth potential values of 0.28 and 0.46 log CFU/g, respectively, for both air and MAP. Substantial growth (>0.5 log CFU/g) was obtained in minced pork after investigating only one batch, with growth potential values of 1.69 and 0.80 log CFU/g, for air and MAP. However, both intra- and inter-batch variability for pork chops and intra-batch variability for minced pork was observed; with elevated growth being evened out by the way growth potential is calculated in the EURL 2014 document, leading to underestimations and posing a potential risk to public health. Maximum growth rate in minced pork at a constant temperature of 7 °C was estimated at μmax = 0.680 log CFU/day and μmax = 0.489 log CFU/day in air and MAP, respectively. Model predictions for the growth potential showed acceptable results for air-packed minced pork with better accuracy when the lag phase was implemented as indicated in the renewed protocol (CRL EU, 2021). In MAP, all models used, including the Combase Growth model and to a lesser extent the DMRI dynamic safety model, overestimate the growth potential probably due to a lack of integration of the changing CO2 levels in the packages. The predictive models used in this study do not adequately account for the dynamics in the raw pig matrix, which may have an inhibitory effect on the growth of L. monocytogenes, including interaction with the microbiome and CO2, and emphasize the importance of remaining critical of predictive model outcomes. In addition, the experimental intra- and inter-batch variability raise questions about the sense or nonsense of using predictive microbiology in these raw pork products.

What are the effects of gamma irradiation, modified atmosphere packaging, and storage on different properties of turmeric essential oil?

Nowadays, the irradiation process has gained great attention in food industries, especially for spices owing to its microbial decontamination power. Therefore, the impact of irradiation on the bioactive compounds and physicochemical attributes of food products needs to be investigated during their shelf life. In the present survey, during one year of storage the impact of gamma irradiation at different doses (0, 5, 10 and 15 kGy) under various packaging atmospheres (air, vacuum and N2) on the chemical components and antimicrobial characteristics of essential oil (EO) and Hunter's color values of turmeric powder was evaluated. The findings showed that by increasing the storage time, and consequently, accelerating the oxidation process, the content of total chemical compounds of EO in all samples decreased and the influence of storage time on the physicochemical attributes of turmeric powder was much stronger than the impact of packaging atmospheres and irradiation. Irradiation was impressive in discoloration (ΔE) of turmeric powder; furthermore, storage time and air atmosphere had an increasing effect on its ΔE.

Effect of Argon as Filling Gas of the Storage Atmosphere on the Shelf-Life of Sourdough Bread-Case Study on PDO Tuscan Bread.

The short shelf-life of PDO Tuscan bread limits its distribution to markets close to the production area, affecting its commercial success and the economic return by supply chain operators. While the application of MAP to store bread is widely accepted, the suitability of this technique to extend the shelf life of the PDO Tuscan bread is still to be explored. Furthermore, to the best of our knowledge no data are available in the literature about the use of argon as filling gas neither in pure atmosphere nor in combination with CO2. In this context, the aim of this study was to evaluate the effect of different modified packaging atmospheres on the shelf-life of sourdough bread. Slices of bread were stored individually in plastic bags at 23 °C in five different atmospheres (Ar (100%), N2 (100%), CO2 (100%), Mix CO2/N2 (70% CO2, 30% N2), Mix CO2/Ar (70% CO2, 30% Ar)), and Air was selected as a control. To select the best storage conditions, both chemical-physical, rheological, and organoleptic features were evaluated. Results showed that pure gases (CO2, N2, Ar) displayed good qualities as storage atmospheres compared to Air. In contrast, both Mix CO2/N2 and Mix CO2/Ar were the best in slowing down the staling process, thus doubling the shelf-life of bread, compared to other atmospheres. In conclusion, argon, as a preservation atmosphere, seems to be the best solution to extend the shelf-life of PDO Tuscan bread.

High-pressure carbon dioxide treatment and vacuum packaging alleviate the yellowing of peeled Chinese water chestnut (Eleocharis tuberosa)

This work evaluated the effects of high-pressure carbon dioxide (HPCD) treatment and vacuum packaging on the yellowing of peeled Chinese water chestnut (CWC) during storage. The changes in color, enzymatic activities, total phenolic content and malondialdehyde contents were assessed in peeled CWC. The results showed that vacuum packaging alone, atmospheric packaging after HPCD treatment, and vacuum packaging after HPCD treatment (HPCD+VP) could significantly delay the yellowing of fresh-cut CWC to varying degrees. The total phenolic content was lower (68%) in HPCD+VP samples than that of control. Compared to control, the enzymatic activities such as phenylalanine ammonia-lyase, polyphenol oxidase and lipoxygenase decreased by 76% (12th day), 24% (6th day) and 19% (6th day) respectively in HPCD+VP samples. HPCD and vacuum packaging could efficiently inhibit several enzymes activities. Our study exhibited that HPCD+VP treatment delayed the yellowing of fresh-cut CWC by reducing the phenylpropanoid metabolism pathway activity and cell membrane peroxidation.