The role of laurel, oregano, and thyme essential oils on the oxidative stability and microbiological quality of sea bass fillets (Dicentrarchus labrax) during refrigerated storage
Die Rolle von ätherischen Lorbeer-, Oregano- und Thymianölen auf die oxidative Stabilität und mikrobiologische Qualität von Wolfsbarschfilets (Dicentrarchus labrax) während der gekühlten Lagerung
This study aimed to investigate the physicochemical (pH, Thiobarbutiric acid number (TBARS), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, L*, a*, b*) and microbiological (total psychrotrophic aerobic bacteria (TPAB), total mesophilic aerobic bacteria (TMAB), Enterobacteriaceae and Pseudomonas counts) and sensory properties in European sea bass (Dicentrarchus labrax) fillets containing laurel, oregano, and thyme essential oil (EO) over 6 days. Treatment with laurel, oregano, and thyme EO had significantly (P < 0.05) higher DPPH levels and lightness values, but lower (P < 0.05) TBARS value. The laurel EO treatment generally did not affect the microorganisms counts of the samples on the 6th day (P > 0.05), while the highest odor score was determined in the groups of laurel EO. The lowest Enterobacteriaceae and Pseudomonas spp. counts were obtained from thyme EO added samples with a 4.59±0.07 log CFU/g and 5.19±0.07 log CFU/g, followed by samples treated with oregano EO with 4.82±0.02 log CFU/g and 5.21±0.05 log CFU/g respectively, at the end of the 6 days of storage.
Bayram Ürkek, Hüseyin Ender Gürmeriç, Mustafa Şengül, Cemalettin Baltacı
Preliminary investigations of ice creams for the determination of the physicochemical properties and aroma compounds by GC-MS produced from cow, sheep, goat, and buffalo milk
Voruntersuchungen an Speiseeis, hergestellt aus Kuh-, Schaf-, Ziegen- und Büffelmilch, zur Bestimmung der physikalisch-chemischen Eigenschaften und Aromastoffe
In the present study, four different ice creams were produced using cow, buffalo, goat, and sheep milk. The physicochemical, sensory properties and aroma profile analyzes of ice creams were carried out and the differences were evaluated. Dry matter rates of cow ice cream (CIC), goat ice cream (GIC), sheep ice cream (SIC) and buffalo ice cream (BIC) ranged from 27.96% to 30.51% and SIC had the highest content of dry matter (30.51%). Ash values of ice creams were determined between 0.61% and 0.75%. Titratable acidity values varied between 0.11% and 0.18%. pH values of ice creams ranged from 6.49 to 7.04. Fat values of ice creams were determined between 4.05 (g/100g) and 5.10 (g/100g). The lowest overrun value (20.61%) was determined in SIC. The highest first dripping time (1980 s) and complete melting time (5970 s) were found in GIC. A total of 41 aroma compounds were determined by gas chromatography-mass spectrometry (GC-MS) and the BIC was the most aromatic product containing 36 aroma compounds. After the BIC, 15, 13 and 8 aroma compounds were detected in CIC, GIC and SIC, respectively. Additionally, aroma compounds 2-hexanone, 2-heptanone, limonene, 2-nonanone, 2-undecanone, 2-tridecanone, 2-pentadecanone were detected in all ice cream types. To evaluate the correlations between the aroma compounds, the principal component analysis (PCA) method was applied to ice cream samples and a strong positive relation was detected between CIC and GIC. In terms of sensory analysis, general acceptability properties were not statistically different (p>0.05) between all ice creams. SIC had the lowest flavor score and CIC had the highest one as sensory property.
Selin Kalkan, Selahaddin Batuhan Akben, Demet Çanga
Suppressing E. coli activation in probiotic yogurt during fermentation by supplementing bitter melon (Momordica charantia L.) ethanol extract
Unterdrückung von E. coli in probiotischem Joghurt während der Fermentation durch den Zusatz von Ethanolextrakt aus Bittermelonen (Momordica charantia L.)
In this study, the survival of Escherichia coli (ATCC® 25922™) in probiotic yogurt supplemented with or without Momordica charantia L. ethanol extract (MCE) during the fermentation period (0–300 minutes) was analysed for various inoculation levels (102; 104 and 106 log CFU/mL). So, the measured E. coli number was modelled as a function of fermentation time and the number of inoculated E. coli. The polynomials models were calculated separately for the probiotic yogurts with and without MCE added. Then, E. coli numbers predicted by the models were analysed using various scientific methods (Transforming predicted E. coli numbers into images, image processing, and hierarchical classification algorithms). The analysis results showed that the E. coli inactivation at between 2.44–3.47 log CFU/mL depending on inoculation levels was determined at the end of fermentation for probiotic yogurts supplemented with MCE. However, the determined inactivation for probiotic yogurts without MCE was between 1.84–2.99 log CFU/mL.