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The applicability of an electronic nose for the quality control of modified atmosphere (MA) packaged broiler chicken cuts was evaluated in different temperature regimes. The electronic nose results were compared with those obtained by microbiological, sensory and headspace GC analyses. The electronic nose could clearly distinguish broiler chicken packages with deteriorated quality from fresh packages either earlier than or at the same time as the sensory quality deteriorated. Concerning the microbiological quality, the counts of Enterobacteriaceae and hydrogen sulphide-producing bacteria were most consistent with the electronic nose results. The results indicated that the electronic nose was capable of detecting even early signals of spoilage in MA packed poultry meat.

The aim of this research was to study whether electronic nose sensor technology (NST 3320, Applied Sensor, Sweden) can be used effectively for monitoring of the composting process. The effect of aeration on the composting process was examined using two aeration levels representing insufficient and optimal aeration for composting. An additional aim was to identify possible indicator gases in the volatile organic compound profiles of the composts by on-line FT-IR and gas chromatographic determinations. The results indicated that the electronic nose was able to distinguish between the two composter bins after 13 days of composting. Of the volatile metabolites that were identified, methyl ethyl ketone (MEK) proved to be a suitable indicator compound of anaerobicity as it was only produced in considerable quantities in the insufficiently aerated composter bin.

The effect of microbial inoculation on the mineralization of naphthalene in a bioslurry treatment was evaluated in soil slurry microcosms. Inoculation by Pseudomonas putida G7 carrying the naphthalene dioxygenase (nahA) gene resulted in rapid mineralization of naphthalene, whereas indigenous microorganisms in the PAH-contaminated soil required a 28 h adaptation period before significant mineralization occurred. The number of nahA-like gene copies increased in both the inoculated and non-inoculated soil as mineralization proceeded, indicating selection towards naphthalene dioxygenase producing bacteria in the microbial community. In addition, 16S rRNA analysis by denaturing gradient gel electrophoresis (DGGE) analysis showed that significant selection occurred in the microbial community as a result of biodegradation. However, the indigenous soil bacteria were not able to compete with the P. putida G7 inoculum adapted to naphthalene biodegradation, even though the soil microbial community slightly suppressed naphthalene mineralization by P. putida G7.

Relation between sensory profiles and flavour-active volatile compounds was explored on six rye extrudates, representing two rye cultivars (Amilo and Akusti) and three pretreatments (germination, sourdough fermentation and milling), prior to the extrusion cooking. The processing method used before the extrusion cooking was shown to be very decisive for the perception; the germinated, sourdough fermented and milled rye extrudates clustered to cultivar pairs according to their pretreatment on the regression plot including the whole sample set. Germinated, extruded rye was cereal and fresh in flavour, and hard in texture, and dimethyl sulphide and 2-methylbutanal were highly related to these sensory attributes. Sourdough fermented, extruded rye had a sour, intense flavour and aftertaste, and porous texture, the most relevant volatile compounds being furfural, ethyl acetate, 3-methylbutanol and 2-methylbutanol. The extrudates prepared from rye flour were very mild in flavour and somewhat tough in texture, and 2-ethylfuran, 2-methylfuran, hexanal and pentanal were the dominating volatile compounds. The present study clearly demonstrated the effect of processing on adjusting the flavour of rye. Sensory perception and volatile compounds of germinated, sourdough fermented, and native rye were substantially different, and they remained variable after the second treatment, i.e. the extrusion process. The pretreatment process was shown to be most dominant in the formation of the flavour of the rye extrudates. The rye cultivar had an unsubstantial effect on the sensory profiles.

Printing inks containing a certain reactive substance indicating oxygen, and suitable for printing onto plastic materials have been produced. This kind of indicator signals for package leakage and can be used for perishable foods in packages with modified atmosphere. Another type of oxygen indicator has been designed to be activated during the sterilisation process, and is most suitable for medical applications. In addition to oxygen indicators, attention was paid to the concept of freshness indicators. Humidity indicator and ethylene indicator developments were started in the project and, later on, advanced in separate projects. Every indicator system is based on a distinctive chemical reaction. Thus, several active substances were identified and tested, and the most promising systems were chosen for further development. The formulation and design of the ink-jet ink has been carried out. A large number of raw material combinations have been tried out to find a viable system. Preliminary reliability studies in real operational environment in food or medical packages have been performed. Two types of oxygen indicators are under evaluation at potential customers.

The quality changes of modified atmosphere packaged broiler chicken cuts during cold storage were monitored using four different method groups: time–temperature indicators (TTIs), microbiological analyses, quality indicating metabolites and sensory evaluation. The comparison of the sensitivities of the quality indicating method groups was performed using principal component analysis (PCA). According to PCA, the microbiological analyses and the TTIs give the same result and are more critical than either the quality indicating metabolites or sensory evaluations. The group consisting of a wide variety of quality indicating metabolites was least critical.

Electronic nose may provide a novel tool for the quality control purposes of various perishable food products. The aim of this study was to test the applicability of electronic nose (NST 3320, Applied Sensor, Sweden) for the quality control of modified atmosphere (MA) packed broiler chicken cuts stored at different temperature conditions. Microbiological and sensory analyses as well as headspace gas chromatographic measurements were used as the reference methods. Fresh broiler chicken cuts packed in the gas mixture of 80% CO2 + 20% N2 were stored for 14 days at three different temperature profiles one of which was constant (+6°C) and the others were variable. The variable temperatures simulated an ideal distribution chain with constant cold chain and a distribution chain with unfavourable temperature variations. During the shelf-life study, electronic nose, microbiological and sensory analyses were used to evaluate the quality of the samples. In addition concentrations of hydrogen sulphide and dimethyl sulphide in the packages were determined using gas chromatographic techniques. The results obtained with the electronic nose and the reference methods were highly consistent. Electronic nose appeared to be capable of detecting even the early signals of spoilage in poultry meat.