Grith Mortensen

Potential of biobased materials for food packaging

Abstract During the last decade, joint efforts by the packaging and the food industries have reduced the amount of food packaging materials. Nonetheless, used packaging materials are still very visible to the consumer in the context of disposal. Environmental issues are becoming increasingly important to the European consumer. Consequently, consumer pressure may trigger the use of biobased packaging materials as an alternative to materials produced from non-renewable resources. Biologically based packaging is defined as packaging containing raw materials originating from agricultural sources, i. e. produced from renewable, biological raw materials such as starch and bioderived monomers. These materials are not necessarily biodegradable. Consequently, this review is not limited to biodegradable packaging. To date, biodegradable packaging has commanded great attention, and numerous projects are under way in this field. One important reason for this attention is the marketing of environmentally friendly packaging materials. Furthermore, use of biodegradable packaging materials has the greatest potential in countries where landfill is the main waste management tool. Biobased packaging materials include both edible films and edible coatings along with primary and secondary packaging materials. Excellent in-depth reviews on edible films and coatings are already available 1 , 2 , 3 . Therefore, this review focuses on biobased primary packaging materials for foods. Several concerns must be addressed prior to commercial use of biobased primary food packaging materials. These concerns include degradation rates under various conditions, changes in mechanical properties during storage, potential for microbial growth, and release of harmful compounds into the packaged food product. Furthermore, the biopackaging must function as food packaging and meet the requirements of the individual food product. This review evaluates the suitability of biobased packaging for foods. Additionally, it identifies the challenges involved when using biobased packaging for different foods.

Light-induced changes in packaged cheeses: a review

Abstract This review presents current knowledge on light-induced effects on packaged cheeses. As research in this area is somewhat limited and involves highly non-standardized light exposure conditions, the review includes, if deemed necessary, effects observed in other dairy products. Most of these effects may be explained by general lipid oxidation mechanisms combined with knowledge on the spectral balance between the singlet oxygen quencher, β -carotene, and the sensitizer, riboflavin. As determined by Lambert-Beers law, β -Carotene absorbs light in a concentration-dependent manner, which would otherwise be absorbed by riboflavin, thereby inducing quality changes. Consequently, these processes may be prevented by total exclusion of light and by storage in an oxygen-free atmosphere. Unfortunately, quality changes are apparent at residual oxygen levels even as low as 0.5% in headspace, which is often considered an acceptable residual oxygen level in industry. For a given product composition, spectral distribution and photon flux of the light source determine the extent of quality changes, since photochemical processes have limited temperature dependence, in contrast to the consecutive lipid autoxidation process. Hence, precautionary measures include changes of light source and targeted prevention of photon flux relative to the cheese by use of creative packaging. In order to optimize packaging and display conditions, a substantial need exists for analytical methods, which reflect the sensory perception of the consumer. Once established, optimization to include marketing and consumer aspects will harbor no major obstacles.

Fluorescence spectroscopy: a rapid tool for analyzing dairy products.

This paper gives a critical evaluation of the use of fluorescence spectroscopy for measuring chemical and physical changes in dairy products caused by processing and storage. Fluorescence spectroscopy is able to determine various properties of foods without use of chemicals and time-consuming sample preparation. This is shown by examples where the measurement of a given chemical parameter has been appropriately described and validated, as well as situations showing potential applications, but where further research and validation is required. The interpretation of fluorescence spectroscopic data is complex due to absorbance by other molecular groups, changes caused by variation in the sample matrix, etc. It is illustrated how advanced data analytical techniques are required to obtain optimal interpretation of the data. Even though the review focuses on examples from the dairy industry, the principles are broader and can be applied to other fields of food and agricultural research.

Potential Food Applications of Biobased Materials. An EU-Concerted Action Project

The objective of the study was to ascertain the state of the art with regard to the applicability of biobased packaging materials to foods and to identify potential food applications for biobased materials. The study revealed relatively few examples of biobased materials used as primary, secondary or tertiary packaging materials for foods. This is due to the fact that published investigations on the use of biobased materials are still scarce, and results obtained remain unpublished because of commercial pressures. The scientific literature contains numerous reports on applications of edible films and coatings to food but novel commercial applications of these are scarce. Based on information currently available on the properties of biobased packaging materials the study identified products in the fresh meat, dairy, ready meal, beverage, fruit and vegetable, snack, frozen food and dry food categories where conventional packaging may be replaced by biobased packaging.

Effect of specific wavelengths on light-induced quality changes in Havarti cheese

The effects of exposure of slices of Havarti cheeses to monochromatic light of wavelengths 366 nm, 405 nm, and 436 nm, respectively, were studied by tristimulus colorimetry, solid-phase microextraction gas chromatographic analysis of volatiles, and open-end fluorescence spectroscopy. Having determined the photon fluxes of the three wavelengths by ferrioxalate actinometry, it was possible to quantify the effects of light exposure in an absolute manner. For all analyses, the most severe effects were caused by visible light, leading to colour bleaching, change in hue, riboflavin degradation, and formation of the secondary oxidation products hexanal, 1-pentanol, and 1-hexanol. Apparent quantum yields for formation of hexanal and 1-pentanol were found to be insignificantly different for 405 nm and 436 nm exposures, having values of (3-5) x 10(-5) mol x einstein(-1) and (9-13) x 10(-5) mol x einstein(-1), respectively. These compounds were not formed when exposed to 366 nm light. In contrast, 1-hexanol was formed when exposing cheese to all three wavelengths, resulting in apparent quantum yields of (2-6) x 10(-5) mol x einstein(-1). The results obtained are discussed in relation to the interplay between inherent product colorants, light sources, and transmission characteristics of the packaging materials.

Time-Saving Design of Experiment Protocol for Optimization of LC-MS Data Processing in Metabolomic Approaches

We describe a time-saving protocol for the processing of LC-MS-based metabolomics data by optimizing parameter settings in XCMS and threshold settings for removing noisy and low-intensity peaks using design of experiment (DoE) approaches including Plackett-Burman design (PBD) for screening and central composite design (CCD) for optimization. A reliability index, which is based on evaluation of the linear response to a dilution series, was used as a parameter for the assessment of data quality. After identifying the significant parameters in the XCMS software by PBD, CCD was applied to determine their values by maximizing the reliability and group indexes. Optimal settings by DoE resulted in improvements of 19.4% and 54.7% in the reliability index for a standard mixture and human urine, respectively, as compared with the default setting, and a total of 38 h was required to complete the optimization. Moreover, threshold settings were optimized by using CCD for further improvement. The approach combining optimal parameter setting and the threshold method improved the reliability index about 9.5 times for a standards mixture and 14.5 times for human urine data, which required a total of 41 h. Validation results also showed improvements in the reliability index of about 5-7 times even for urine samples from different subjects. It is concluded that the proposed methodology can be used as a time-saving approach for improving the processing of LC-MS-based metabolomics data.

Site-Specific Detection of Radicals on α-Lactalbumin after a Riboflavin-Sensitized Reaction, Detected by Immuno-spin Trapping, ESR, and MS

Free radicals and other oxidation products were characterized on α-lactalbumin with electron spin resonance (ESR), immuno-spin trapping, and mass spectrometry (MS) after riboflavin-mediated oxidation. Radicals were detected using the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) in immuno-spin trapping with both enzyme-linked immunosorbent assay (ELISA) and Western blotting and further characterized with mass spectrometry. A DMPO-trapped radical was identified at His68 and another at one of the tyrosine residues, Tyr50 or Tyr36, respectively, generated by a type II or I mechanism. Not all tyrosyl radicals were trapped, as the secondary oxidation product, 3,4-dihydroxyphenylalanine (DOPA), was detected by mass spectrometry at Tyr18 and Tyr50. A further oxidation of DOPA resulted in the DOPA o-semiquinone radical, which was characterized by ESR. Both surface exposure and the neighboring residues in the local environment of the tertiary structure of α-lactalbumin seem to play a role in the generation of DMPO trapped radicals and secondary oxidation products.

Effect of Antioxidants on Oxidation during the Production of Whey Fat Concentrate

Whey fat has a relatively high level of unsaturated fatty acids, and as such, whey products with a high fat content are vulnerable to oxidation. The purposes of the present study were to assess the oxidative development in whey fat concentrate (WFC) during production and investigate the effect of the addition of antioxidants. Green tea extract (GTE) or a mixture of ascorbyl palmitate and tocopherol (AP/TOC) were used, each in two concentrations. Samples were taken before and after pasteurization of WFC and after drying. The level of volatile oxidation products decreased during processing, while dityrosine concentrations increased during drying. GTE reduced oxidation in both unpasteurized and pasteurized WFC, while the effect of AP/TOC was nonsignificant. In the WFC powder, there was no significant effect of the antioxidants. In conclusion, results indicated that GTE was able to inhibit oxidation in WFC during production and that AP/TOC addition had no effect.