Tvær greinar frá Rf í virtu vísindatímariti.

2.9.2005

Greinarnar tvær birtust í septemberhefti Journal of Food Science sem nýkomið er út grein. Er Rósa Jónsdóttir, matvælafræðingur á Rf fyrsti höfundur annarar greinarinnr, en einn af höfundum hinnar er Kínverjinn Zeng, en hann stundaði nám við Sjávarútvegsskóla Sameinuðu þjóðanna árin 2003 og 2004.

Það þykir ætíð heiður að fá greinar birtar í viðurkenndum vísindatímaritum, bæði fyrir viðkomandi vísindamenn og einnig fyrir þær stofnanir sem þeir vinna hjá, því miklar kröfur eru gerðar til greinarhöfunda.

Hér eru upplýsingar um greinarnar, en þær birtust á vefnum www.ift.org:

Jónsdóttir R, Bragadóttir M, and Arnarson GÖ. 2005. Oxidatively Derived Volatile Compounds in Microencapsulated Fish Oil Monitored by Solid-phase Microextraction (SPME). J Food Sci 70(7):C433-440.
Abstract: The stability of microencapsulated fish oil was studied during storage at 4°C for up to 20 wk. Different coating mixtures consisting of gelatin or caseinate in blends with carbohydrates (sucrose, lactose, maltodextrin) were investigated. Oxidative stability of the microencapsulated fish oil was monitored by analysis of volatile compounds using gas chromatography olfactometry (GC-O) or GC flame ionization (GC-FID) (SPME-HS-GC/O or GC/FID and HS-GC/MS), Oxipres test, thiobarbituric acid-reactive substances (TBARS), and sensory analysis. Coating mixture of caseinate and lactose showed slightly better stability than the sucrose and maltodextrin caseinate mixtures. Combination of fish gelatin and maltodextrin did not show as good oxidative stability as the coating blend of caseinate, lactose, and lecithin. Hexanal, 2-nonenal and 2,4-decadienals were selected as quality indicators to monitor the lipid oxidation during storage of the samples. SPME-GC-O analysis of these indicators showed that they were representative for the oxidation occurring in the microencapsulated fish oil. SPME-GC–FID analysis was sensitive enough to detect oxidative changes during storage. Oxidative stability test, TBARS results, and sensory analysis were in agreement with the SPME, indicating that SPME (polydimethylsiloxane/divinylbenzene [PDMS/DVB] fiber) can be a useful tool for rapid analysis of lipid oxidation in microencapsulated fish oil.
Keywords: microencapsulated fish oil, SPME, lipid oxidation, volatile compounds, gas chromatography–olfactometry (GC-O)

Zeng QZ, Thorarinsdottir KA, and Olafsdottir G. 2005. Quality Changes of Shrimp (Pandalus borealis) Stored under Different Cooling Conditions. J Food Sci 70(7):S459-466.
Abstract: The influence of different cooling techniques and storage temperatures (–1.5°C or 1.5°C) to prolong the shelf life of shrimp was evaluated by sensory analysis, physical methods, chemical analysis, and microbial analysis. Storage in liquid ice was more effective than flake ice or brine mixed with flake ice in delaying spoilage of the shrimp by slowing down microbial growth and formation of total volatile basic nitrogen (TVB-N) and trimethylamine (TMA). Total viable counts (TVC) showed that bacteria grew most quickly in shrimp stored in flake ice and in brine mixed with flake ice, followed by those in liquid ice at 1.5°C and –1.5°C, respectively. Lowest counts were observed in shrimp stored in liquid ice at –1.5°C where the lag phase of growth was apparently extended at the beginning of storage. Principal component analysis (PCA) showed a good correlation between quality indicators related to microbial growth, TVC, pH, TVB-N, TMA, responses of an electronic nose and sensory evaluation.
Keywords: liquid ice, superchilling, electronic nose, sensory evaluation, spoilage




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