C. Pérez-Lamela

Analytical methods for food-contact materials additives in olive oil simulant at sub-mg kg-1 level.

Methods of analysis for four additives (two antioxidants, IRGANOX 245 and 1035; an ultraviolet absorber, CHIMMASORB 81; and an optical brightening agent, UVITEX OB) in olive oil are reported. These additives have the potential to migrate from food-contact materials into the European Union fatty food simulant olive oil, which is the most difficult matrix for analysis. The additives were chosen because they differed in their chemically active groups, had different functions within the polymer, have low proposed specific migration limits and are commonly used in food-contact materials such as polystyrenes and polyolefins. The proposed analytical methods for the additives are simple, rapid, inexpensive and also broadly applicable to the aqueous food simulants. All methods were evaluated by constructing calibration curves, measurement of recovery and precision, and determining the limits of detection. Most of the methods involve direct injection of an olive oil solution for high-performance liquid chromatography analysis with ultraviolet-visible or fluorescence detection. The methods allowed establishment of additive stability and measurement of migration of the selected additives into olive oil at different time-temperature conditions used in migration studies into food simulants.

Training of panellists for the sensory control of bottled natural mineral water in connection with water chemical properties.

As bottled mineral water market is increasing in the world (especially in emergent and developed countries), the development of a simple protocol to train a panel to evaluate sensory properties would be a useful tool for natural drinking water industry. A sensory protocol was developed to evaluate bottled natural mineral water (17 still and 10 carbonated trademarks). The tasting questionnaire included 13 attributes for still water plus overall impression and they were sorted by: colour hues, transparency and brightness, odour/aroma and taste/flavour/texture and 2 more for carbonated waters (bubbles and effervescence). The training lasted two months with, at least, 10 sessions, was adequate to evaluate bottled natural mineral water. To confirm the efficiency of the sensory training procedure two sensory groups formed the whole panel. One trained panel (6 persons) and one professional panel (6 sommeliers) and both participated simultaneously in the water tasting evaluation of 3 sample lots. Similar average scores obtained from trained and professional judges, with the same water trademarks, confirmed the usefulness of the training protocol. The differences obtained for trained panel in the first lot confirm the necessity to train always before a sensory procedure. A sensory water wheel is proposed to guide the training in bottled mineral water used for drinking, in connection with their chemical mineral content.

Simultaneous HPLC–DAD quantification of vitamins A and E content in raw, pasteurized, and UHT cow’s milk and their changes during storage

An improved extraction and HPLC method for the simultaneous extraction and quantitation of retinol, α-tocopherol, α-tocotrienol, and β-carotene was developed to analyze commercial whole/semi-skim/skim samples of raw/pasteurized/UHT milk in transparent plastic/glass bottles and Tetra Brik™ containers. The sample preparation method required prior saponification at 40xa0°C for 15xa0min followed by n-hexane extraction. An isocratic acetonitrile/methanol (65:35 v/v) mobile phase, C18 analytical column, and UV detector were chosen for HPLC quantification. The liposoluble vitamin content in raw, pasteurized conventional/organic, and UHT milk ranged 0.055–5.540 (retinol), 0.135–1.410 (α-tocopherol), and 0.040–0.850xa0mg/L (β-carotene). No significant differences (pxa0>xa00.05) were observed on losses of retinol, α-tocopherol, and β-carotene content in UHT whole milk after 5xa0days at 4xa0°C in the dark. After 14xa0days at 4xa0°C in the dark, the contents of retinol, α-tocopherol, and β-carotene remained higher in milk with higher fat content and were higher in unopened containers. In UHT whole milk, samples containing 0.02xa0% NaN3, retinol (33xa0%), and α-tocopherol (11xa0%) but not β-carotene (2xa0%) decreased significantly (pxa0<xa00.05).

HPLC method for determining ethylenediamine migration from epoxy-amine food packaging coatings into EU food simulants

A simple, rapid, sensitive and inexpensive method has been developed for the determination of ethylenediamine (EDA) in European Union food simulants. The method involves precolumn derivatization with ortho-phthaldehyde (OPA) and 2-mercaptoethanol (ME) to obtain a fluorescent derivative. Liquid chromatographic (HPLC) elution was achieved with methanol-ultrapure water (65:35) as mobile phase with a Waters Spherisorb 5 mu;m ODS 2 column. Fluorescence detection (FD) was performed at 330 nm (excitation wavelength) and 450 nm (emission). Total chromatographic analysis time was < 10 min. The proposed method was validated by checking linearity, detection and quantification limits, and precision. Relative recovery rates were of about 100% because samples and standard-spiked blanks were processed in the same way. Method precision (RSD < 6%) was satisfactory and the quantification limit (0.25 mg l-1) indicated that specific migration limit for EDA in EU food simulants (12 mg kg-1) can be easily controlled. When the validated method was applied to epoxy-amine formulations used for can coatings under different curing conditions, EDA migration was < 1.4 mg l-1.