Search results for "Food Handling"
showing 10 items of 144 documents
Mathematical Model of Solid Food Pasteurization by Ohmic Heating: Influence of Process Parameters
2013
Pasteurization of a solid food undergoing ohmic heating has been analysed by means of a mathematical model, involving the simultaneous solution of Laplace’s equation, which describes the distribution of electrical potential within a food, the heat transfer equation, using a source term involving the displacement of electrical potential, the kinetics of inactivation of microorganisms likely to be contaminating the product. In the model, thermophysical and electrical properties as function of temperature are used. Previous works have shown the occurrence of heat loss from food products to the external environment during ohmic heating. The current model predicts that, when temperature gradient…
Application of propidium monoazide-qPCR to evaluate the ultrasonic inactivation of Escherichia coli O157:H7 in fresh-cut vegetable wash water.
2012
The efficacy of sanitizing technologies in produce or in vegetable wash water is generally evaluated by plate count in selective media. This procedure is time consuming and can lead to misinterpretations because environmental conditions and sanitizing processes may affect bacterial growth or culturable capability. Thus, the aim of this study was to determine the applicability of a propidium monoazide real-time PCR (PMA-qPCR) method to monitor the inactivation by ultrasound treatment of foodborne bacteria in fresh-cut vegetable wash water. To this aim, lettuce wash water was artificially inoculated with Escherichia coli O157:H7 (10⁶ CFU/mL) and treated by means of a continuous ultrasonic irr…
Biogenic amines in wines from three Spanish regions.
2005
One hundred and sixty-three wines from La Rioja, Utiel-Requena, and Tarragona were analyzed to determine if there were any differences in the concentrations of six biogenic amines that are found in these three regions. The influence of grape variety, type of vinification, wine pH, malolactic fermentation, and storage in bottle on biogenic amine concentrations was studied. Results show important differences in putrescine and histamine concentrations among regions, varieties of grape, and type of wine; differences were less appreciable for the remaining biogenic amines studied. Low pH prevented biogenic amine formation. Malolactic fermentation and short storage periods in bottle (3-6 months) …
Evolution of microbiological and chemical parameters during red wine making with extended post-fermentation maceration.
2014
Abstract The aim of the present work was to investigate the microbiological, chemical, and sensory characteristics of red wine subjected to post-fermentation maceration that was extended to 90 days. For this purpose, the ‘Aglianico di Taurasi’ grape was used as a case study. The total yeast concentration increased until day 40 of maceration and decreased thereafter, whereas the concentration of lactic acid bacteria slightly increased. Dekkera/Brettanomyces spp. and acetic acid bacteria were not detected. The yeast community was composed of Saccharomyces cerevisiae, Zygosaccharomyces bisporus, Metschnikowia pulcherrima, Hanseniaspora guilliermondii, Hanseniaspora uvarum, Pichia guilliermondi…
Use of a logistic model to assess spoilage by Byssochlamys fulva in clarified apple juice
2010
Abstract The percentage P (%) of spoiled bottles (n = 40) of clarified apple juice due to Byssochlamys fulva, was modeled by using a logistic model: P = P max 1 + exp ( k ( τ − t ) ) where Pmax (%) the maximum percentage of spoiled bottles, k (h− 1) a slope parameter and τ (h) the time for P = Pmax/2. Bottles of pasteurized apple juice were inoculated with B. fulva IOC 4518 ascospores for low and high initial loads, 4.8 ± 2.3 ascospores/100 mL and 19.3 ± 4.6 ascospores/100 mL respectively and incubated at 21 °C and 30 °C. Pmax was not significantly different from 100% except for a low initial load at 21 °C. Model parameters were estimated with a good accuracy, RMSE in the range 3.89–7.50. T…
Near-infrared diffuse reflectance spectroscopy and neural networks for measuring nutritional parameters in chocolate samples.
2007
Abstract A rapid and non-destructive method has been developed for the characterization of chocolate samples based on diffuse reflectance near-infrared Fourier transform spectroscopy (DRIFTS) and artificial neural networks (ANNs). This methodology provides a potentially useful alternative to time-consuming chemical methods of analysis. To assess its utility, 36 chocolate samples purchased from the Spanish market were analyzed for the determination of the main nutritional parameters like carbohydrates, fat, proteins, energetic value and cocoa content. Direct triplicate measurements of each sample were carried out by DRIFTS. Cluster hierarchical analysis was used for selecting calibration and…
Methods of in vitro toxicology
2002
In vitro methods are common and widely used for screening and ranking chemicals, and have also been taken into account sporadically for risk assessment purposes in the case of food additives. However, the range of food-associated compounds amenable to in vitro toxicology is considered much broader, comprising not only natural ingredients, including those from food preparation, but also compounds formed endogenously after exposure, permissible/authorised chemicals including additives, residues, supplements, chemicals from processing and packaging and contaminants. A major promise of in vitro systems is to obtain mechanism-derived information that is considered pivotal for adequate risk asses…
Conventional, non-conventional extraction techniques and new strategies for the recovery of bioactive compounds from plant material for human nutriti…
2019
Considering a large number of variations in the chemical structures of bioactive compounds (BACs) that are valuable to humans and a large number of their sources, it is necessary to build a standard and integrated extraction and analytical approaches for obtaining these compounds. From this perspective, the main purpose of this Special Issue of Food Research International was to publish research related to the extractions with data about isolation of BACs from plant matrices for human nutrition. This Special Issue includes both, conventional and innovative extraction techniques, highlighting their characteristics and advantages in relation to the target matrix. Many of presented works conta…
Influence of packaging on the aroma stability of strawberry syrup during shelf life
2001
Different types of packaging (glass bottle, PVC, and PET) were compared for the preservation of aroma quality of a strawberry syrup during shelf life. Esters, alcohols, and aldehydes were analyzed by solid-phase micro-extraction (SPME) and solvent extraction. During storage, hydrolysis of esters in acids and alcohols led to a modification of the aroma profile which can be explained by the replacement of “fruity” and “fresh” notes by “dairy note” in the syrup. Aroma compounds that are responsible for fruity notes, such as methyl cinnamate, methyl anthranilate, and methyl dihydrojasmonate, were strongly reduced after 90 days. This could be explained by a selective interaction of these compoun…
Effects of thermal processing and storage on available lysine and furfural compounds contents of infant formulas.
2000
The Maillard reaction-related effects that thermal treatments during the manufacturing process and storage (at 20 and 37 degrees C) have on powdered adapted and follow-up milk-based infant formulas were estimated by measuring the available lysine and furfural compounds contents of raw cow milk used in manufacturing, intermediate products and formulas. A fluorimetric method was used to measure the available lysine contents, and free and total furfural compounds were determined by HPLC. Statistically significant losses in available lysine (about 20%) in the infant formulas with respect to raw milk were found. The storage period did not affect the available lysine contents of adapted formulas …