Liquid Foodstuffs Research Articles

Safety testing of food contact materials: studies of migration of potentially genotoxic compounds from tubes for liquid foodstuffs

Safety testing of food contact materials: studies of migration of potentially genotoxic compounds from tubes for liquid foodstuffs

Killing of microorganisms by pulsed electric fields.

Lethal effects of pulsed electric fields (PEF) on suspensions of various bacteria, yeast, and spores in buffer solutions and liquid foodstuffs were examined. Living-cell counts of vegetative cell types were reduced by PEF treatment by up to more than four orders of magnitude (> 99.99%). On the other hand, endo- and ascospores were not inactivated or killed to any great extent. The killing of vegetative cell types depends on the electrical field strength of the pulses and on the treatment time (the product of the pulse number and the decay time constant of the pulses). For each cell type, a specific critical electric field strength (Ec) and a specific critical treatment time (tc) were determined. Above these critical values, the fractions of surviving cells were reduced drastically. The "limits" Ec and tc depend on the cell characteristics as well as on the type of medium in which the cells are suspended. Especially in acid media living-cell counts were sufficiently decreased at very low energy inputs. In addition to the inactivation of microorganisms, the effect of PEF on food components such as whey proteins, enzymes and vitamins, and on the taste of foodstuffs was studied. The degree of destruction of these food components by PEF was very low or negligible. Moreover, no significant deterioration of the taste of foodstuffs was detected after PEF treatment. Disintegration of cells by PEF treatment in order to harvest intracellular products was also studied. Yeast cells, suspended in buffer solution, were not disintegrated by electric pulses. Hence, PEF treatment is an excellent process for inactivation of microorganisms in acid and in thermosensive media, but not for complete disintegration of microbial cells.

5520943 Method for modifying the quality of liquid foodstuff: Osajima Yutaka; Shimoda Mitsuy; Kawano Tamotsu Fukuoka, Japan assigned to Nippon Tansan Co Ltd

5520943 Method for modifying the quality of liquid foodstuff: Osajima Yutaka; Shimoda Mitsuy; Kawano Tamotsu Fukuoka, Japan assigned to Nippon Tansan Co Ltd

Analysis of atrazine residues in food by an enzyme immunoassay

The application and validation of a highly sensitive and relatively selective enzyme immunoassay (EIA) for the analysis of atrazine residues in food is described. The assay is performed on microtiter plates. The range of detection for atrazine analysis lies between approrimately 1 ng/L and 10 μg/L. Various foods in liquid form such as milk, fruit juices, and vegetable juices and in solid form such as corn were analyzed with the EIA in their natural states and after the samples were spiked with defined amounts of atrazine. The solid food samples had to be extracted before EIA analysis. However, the assay did not require concentration or cleanup steps for any of the liquid foodstuffs analyzed. A comparison with HPLC measurements was made with the extracted food samples

Homogenizer for liquid foodstuffs — consists of twin valve spring-loaded contactor with confuser minimizing pressure loss and energy consumption : Provision Mach SU 1507-268; 15 September 1989

Homogenizer for liquid foodstuffs — consists of twin valve spring-loaded contactor with confuser minimizing pressure loss and energy consumption : Provision Mach SU 1507-268; 15 September 1989

Freeze Concentration of Some Foodstuffs Using Ice Nucleation-active Bacterial Cells Entrapped in Calcium Alginate Gel

Cells of an ice nucleation-active strain of Ermnia ananas were entrapped in calcium alginate to prepare an ice-nucleating gel usable as ice nuclei for freeze concentration. The ice-nucleating gel was also adjusted as to specific gravity. When it was placed at a desired position in a liquid material such as egg white, ice formed at this position as the material was cooled. It was possible to put the ice- nucleating gel in liquid foodstuffs such as egg white and lemon juice before their temperatures reached subzero points. Application of this method produced freeze-concentrated foods whose properties were not significantly deteriorated.

Freeze concentration of some foodstuffs using ice nucleation-active bacterial cells entrapped in calcium alginate gel.

Cells of an ice nucleation-active strain of Erwinia ananas were entrapped in calcium alginate to prepare an ice-nucleating gel usable as ice nuclei for freeze concentration. The ice-nucleating gel was also adjusted as to specific gravity. When it was placed at a desired position in a liquid material such as egg white, ice formed at this position as the material was cooled. It was possible to put the icenucleating gel in liquid foodstuffs such as egg white and lemon juice before their temperatures reached subzero points. Application of this method produced freeze-concentrated foods whose properties were not significantly deteriorated.

Studies on food analysis by using an enzyme. I. A simple method for the determination of formaldehyde in foods.

A simple and rapid enzymatic analysis was developed for the determination of formaldehyde in foods. The liquid food stuffs were diluted with 0.2 M triethanolamine hydrochloride buffer solution (pH 8.1). After the solid food stuffs were steam distilled, the distillate were diluted with the buffer solution (pH 8.1). The test solution was incubated for 15 min at 25±5°C with formaldehyde dehydrogenase (FADH) in the presence of β-nicotinamide adenine dinucleotide (NAD) and reduced glutathione, and then the content of formaldehyde were determined quantitatively from the increasing absorbance at 340 nm by reduced NAD (NADH) formed. The calibration curve for formaldehyde in the range of 0.1μg-10μg was linear. The recoveries of formaldehyde added to various kinds of foods at levels of 2-100μg/g were in the range of 75-105%, and the detection limit was 1μg/g of sample. When the proposed method was applied to 9 kinds of commercial foods, formaldehyde was detected in the range of 1.6-732μg/g. From the results described this enzymatic method was concluded to be a simple and precise analysis of formaldehyde in foods.

Nachweis und Identifizierung von Zuckercouleuren in einigen flüssigen Lebensmitteln

A method for the isolation of caramel colours by ultrafiltration from liquid foodstuffs as vinegar, brandy and soft drinks is described. The identification of the caramel type is definitely possible via Curie point-pyrolysis-HRGC/MS.

Mechanisms and disorders of gastric emptying.

The stomach converts food into fragments and then liquifies it before emptying it into the duodenum. Gastric emptying of liquid foodstuffs is so controlled that about 200 kcal/hr are delivered to the duodenum. The volume of the meal, its energy density (kcal/ml), and the proportions of fat, carbohydrate, and protein in the meal have minor effects on the rate of gastric emptying of energy. Regulation is achieved through the osmotic effect and calcium binding of the products of digestion in the duodenum. There are no receptors that respond to energy.

LIQUID FOODSTUFFS EXHIBITING YIELD STRESS AND SHEAR‐DEGRADABILITY

AbstractTwo rheological properties of liquid foodstuffs often encountered in practice are the yield stress and the shear‐degradability (irreversible time‐dependence). Both these properties were determined for meat and yeast extracts using two rotational viscometers. The material constants were obtained and fitted with Bingham Plastic and Herschel‐Bulkley models for the meat extracts. The shear‐degradability exhibited by the yeast extract was quantified in terms of the energy required to destroy the material structure.

Oxygen doping of carrier gas in the determination of dichloromethane in liquid foodstuffs by headspce gas chromatography with electron-capture detection

Oxygen doping of carrier gas in the determination of dichloromethane in liquid foodstuffs by headspce gas chromatography with electron-capture detection

Rapid Heating of Liquid Foodstuffs at 896 MHz*

ABSTRACTThe design parameters of a TM010 resonant cavity, operating at 896 MHz for the heat treatment of thin cylindrical samples of known dielectric properties, are presented. Comparison is made of the performance of such a cavity with various liquid foodstuffs. The influence of the dielectric liquid temperature on the matching characteristics is experimentally investigated. High utilization efficiencies and heating rates are obtained. The distribution of the axial electric field in the loaded cavity is computed. The electric field pattern pertaining to the TM010 mode is experimentally verified using an electric probe.