50 research outputs found
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MONTE CARLO SIMULATION OF ORANGE JUICE PECTINMETHYLESTERASE (PME) INACTIVATION BY COMBINED PROCESSES OF HIGH HYDROSTATIC PRESSURE (HHP) AND TEMPERATURE
The variability effect of kinetic data was investigated by simulating orange juice pectinmethylesterase (PME) inactivation with combined processes of high hydrostatic pressure-temperature (100-500 MPa; 20-40°C), applying the Monte Carlo method. Parameters from an Eyring-Arrheniius model that predicts the kinetic inactivation constant (k) as a function of both pressure and temperature were found reported in literature and considered for the analysis. The kinetic analysis was carried out with both Monte Carlo simulations and the traditional deterministic approach, which only considers mean values and does not take into account data variability. Simulations with the Monte Carlo method demonstrated that residual PME activity predicted with deterministic calculations greatly differed from those obtained through confidence intervals of simulated probabilistic distributions. Mean values overrated residual enzyme activity from 4% to ≈2,800% when compared to the 95% confidence intervals generated with the Monte Carlo method. This divergence augmented as both applied pressure and temperature levels increased. Similar risk analysis projects can be further developed to establish the foundations for future food processing regulations of enzymatic control.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Universidad Autónoma Metropolitana Unidad Iztapalapa and can be found at: http://www.redalyc.org/revista.oa?id=620.Keywords: Process simulation, High hydrostatic pressure (HHP), Orange juice, Pectinmethylesterase (PME), Monte CarloKeywords: Process simulation, High hydrostatic pressure (HHP), Orange juice, Pectinmethylesterase (PME), Monte Carl
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Inclusion of the variability of model parameters on shelf-life estimations for low and intermediate moisture vegetables
Shelf-life is the time period during which products retain market-acceptable quality while meeting legal and safety requirements. Deterministic models yield single value estimations of shelf-life typically based on average or worst-case values for input parameters. In deterministic calculations, considering the input parameter variability can be challenging. In this study, a Monte Carlo procedure and the G.A.B. model for moisture sorption isotherms were used to predict shelf-life frequency distributions for intermediate moisture (IM) tomato slices, and low moisture (LM) onion flakes and sliced green beans. End of shelf-life for IM tomato slices (initial a[subscript w] = 0.8) was assumed to occur for a 10% moisture loss, and when a[subscript w] changed from 0.25 to 0.4 for LM onion flakes and LM sliced green beans. The estimated shelf-life for tomato slices, LM onion flakes, and LM sliced green beans based on the deterministic approach was 243, 86, and 79 days, respectively. The Monte Carlo procedures yielded shelf-life frequency distributions with values ranging 181–366, 76–95, and 71–90 days, respectively. Products would fail before the deterministic shelf-life value with an unacceptably high probability of 51.6, 48.6, and 53.0%, respectively. If 5% is an acceptable probability that the actual shelf-life is shorter than specified, the estimated values would be 211, 81, and 73 days, respectively. X[subscript m] and K were the most influential G.A.B parameters on the shelf-life of the three products. The package area, product amount, and water vapor transmission rate were high contributors and had the expected effect on shelf-life as demonstrated by deterministic estimations.Keywords: Monte Carlo simulations, Water activity, Moisture sorption isotherms, Shelf-life, G.A.B. model parametersKeywords: Monte Carlo simulations, Water activity, Moisture sorption isotherms, Shelf-life, G.A.B. model parameter
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Analysis of Vibrio vulnificus Infection Risk When Consuming Depurated Raw Oysters
A beta Poisson dose-response model for Vibrio vulnificus food poisoning cases leading to septicemia was used when evaluating the effect of 15°C depuration on the estimated risk of raw oyster consumption. Statistical variability sources included V. vulnificus load at harvest, time and temperature during harvest and transportation to processing plants, decimal reductions (SV) observed during experimental circulation depuration treatments, refrigerated storage time before consumption, oyster size, and number of oysters per consumption event. Although reaching non-detectable V. vulnificus levels (<30 MPN/g) throughout the year and a 3.52 SV were estimated not possible at 95% confidence, depuration for 1, 2, 3, and 4 d would reduce the warm (Jun-Sep) season risk from 2,669 cases to 558, 93, 38, and 47 cases per 100 million consumption events, respectively. At 95% confidence, 47 and 16 h depuration would reduce the warm and transition (Apr-May, Oct-Nov) season risk, respectively, to 100 cases per 100 million consumption events assumed to be an acceptable risk, while 1 case per 100 million events would be the risk when consuming untreated raw oysters in the cold (Dec-Mar) season.Keywords: Depuration, Oyster, Dose-response, Monte Carlo, Risk analysis, Vibrio vulnificusKeywords: Depuration, Oyster, Dose-response, Monte Carlo, Risk analysis, Vibrio vulnificu
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Benefits and limitations of food processing by high-pressure technologies: effects on functional compounds and abiotic contaminants
The continuing and worldwide growth of pressure processing technologies to pasteurize
and sterilize foods justifies the need to study the effects on functional compounds and
nonbiotic contaminants as affected by high pressure processing (HPP) and pressureassisted
thermal processing (PATP). Substantially more research will be required to
determine the complex effects of the food matrix on chemical reactions leading to losses
of nutrients and functional components, production of toxic compounds, and to
modifications of toxic residues of chemicals used in food production or coming from
food contact materials. In PATP treatments, pressure can also increase, decrease or have
no effect on the thermal degradation rate of these substances. HPP has no major
negative and often beneficial effects on the retention of nutrients and functional
components. However, information on PATP effects is very limited and additional
research will be required before implementing this promising new technology.Keywords: polyphenols,
pressure-assisted thermal processing (PATP),
abiotic contaminants,
antioxidants,
food packaging plastic materials,
heterocyclic aromatic amines (HCAs),
acrylamide,
polycyclic aromatic hydrocarbons (PAHs),
chloropropanols,
vitamins,
nonbiotic contaminants,
pesticides,
high-pressure processing (HPP
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Monte Carlo analysis of the product handling and high-pressure treatment effects on the Vibrio vulnificus risk to raw oysters consumers
A Monte Carlo procedure considering the variability in oyster handling from harvest to raw consumption estimated reductions in the number of Vibrio vulnificus induced septicemia cases achieved by high-pressure processing (HPP). The calculations yielded pathogen load distributions in raw oysters from harvest to consumption. In the warm season, 2-6 min treatments at 250 MPa and 1°C would lower the predicted number of septicemia cases associated with raw oyster consumption from 4,932 to less than four per 100 million consumption events (95% confidence). This study highlighted that HPP conditions should be selected according to the seasonal pathogen load and environment temperature. Finally, the procedure emphasized that the variability in the V. vulnificus population at harvest, before and after HPP treatments, reflecting in part the microbiological quantification methods used, significantly affected the estimated number of septicemia cases. Therefore, improving microbiological quantification should provide better predictions of the number of septicemia cases.Keywords: Beta-Poisson dose response models, Monte Carlo analysis, Vibrio vulnificus, Oyster, High pressure processing, Seafood poisoning ris
Minimally processed foods
One of the major growth segments in the food retail industry is minimally processed (MP) foods. This relatively new market trend has strived to develop new technologies or new applications of traditional technologies to preserve the characteristics of excellence in the products, extend shelf-life and improve their microbiological safety. Most of these technologies for gentle preservation are based on the hurdle concept. Additives, modified-atmosphere packaging, the use of essential oils as antioxidants and antimicrobials, the application of edible films, high hydrostatic pressure, high intensity pulsed electric field, high-intensity light pulses, ultraviolet radiation, high-power ultrasound, pulsed light and ozone are some of the leading preservation factors in recent years. The aim of this chapter is to revise the minimal process concept and to give an overview of mild technologies developed to extend the shelf-life of these products.Fil: Alzamora, Stella Maris. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Lopez Malo, A.. Universidad de las Américas Puebla; MéxicoFil: Tapia, M. S.. Universidad Central de Venezuela; VenezuelaFil: Welti Chanes, J.. Tecnológico de Monterrey; Méxic
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Phytochemicals and antioxidant activity of juice, flavedo, albedo and comminuted orange
Citrus fruits contain phytochemicals effective in the prevention/treatment of chronic diseases. Although many orange peel phytochemicals have been identified, information on their distribution in flavedo and albedo is incomplete limiting the development of applications for orange byproducts including comminuted orange obtained by grinding peel/juice and used in beverage formulations. Phytochemical concentration, antioxidant activity (AOA) and their relationship were determined for comminuted orange, juice and peel fractions. The highest vitamin C (74.7–98.2 mg ascorbic acid/100 g), flavones (235.9–265.0 mg hesperidin/100 g) and carotenoid (1.04–6.21 mg β-carotene/100 g) contents were found in flavedo. Albedo was the main source of phenolics (553.1–730.0 mg gallic acid/100 g), flavanones (1450.0–2084.5 mg hesperidin/100 g), and AOA (11953.2–15484.0 μmol trolox/100 g). AOA linearly correlated with phenolic, hesperidin, and flavonoid concentrations. Orange peel increased the phenolics, flavonoids and AOA of comminuted orange by 111%, 783% and 304%, respectively, when compared with juice, showing that these byproducts are a superior source of nutraceuticals.Keywords: albedo, flavedo, carotenoids, juice, flavonoids, vitamin C, phenolic compounds, comminuted orange, antioxidant activit