Aktuelle Themen

Aktuelle Themen

Aktuelle Themen


1123
Impact of UV-C and thermal pasteuri­zation on bioactive compounds, sensory ­characteristics and aroma profile of ­traditionally produced koruk vinegar
Auswirkungen von UV-C und thermischer Pasteurisierung auf bioaktive ­Verbindungen, sensorische Eigenschaften und das Aromaprofil von traditionell hergestelltem Koruk-Essig

The aim of the study was to examine the effects of UV-C light applied by a designed reactor on bioactive components of traditionally produced koruk vinegar. Furthermore, microbial load, 5-HMF content, the volatile compounds, sensorial attributes and colour of vinegar were assessed. A reduction of 1.29-log CFUmL–1 was achieved in total aero­bic bacteria by applying a dose of 262.4 mJcm–2. A total of 22 volatile compounds were determined in the traditionally produced vinegar. Among bioactive compounds, only total phenolic content changed significantly during UV-C treatment while antioxidant activity, total flavonoid and ascorbic acid content was not affected. Although the ­characteristic pungent sensation, aromatic intensity and richness in aroma of pasteurized vinegar significantly decreased, a non-significant difference in the sensorial properties was ­determined in all UV-C irradiated vinegar. UV-C treatment has potential for non-thermal pasteurization of koruk vinegar compared to thermal one due to the more ­preservative of its fresh-like characteristics.

Mehtap Çelik, Nilgün Öncül
Microbiological quality and nutritional ­values of honey bee pollen
Mikrobiologische Qualität und Nährwerte von Honigbienenpollen

The present study was aimed at examining the microbiological, physicochemical, and antioxidant properties of bee pollen samples collected from beekeepers in western Turkey. The results ranged between 2.24–6.87 log CFU/g, 1.98–3.77 log CFU/g, <1.00–2.51 log CFU/g, 4.19–5.30 log CFU/g, and 1.98–3.74 log MPN/g for total mesophilic aerobic bacteria, yeasts, molds, lactic acid bacteria, and total coliform, respectively. S. aureus was under detectable level. Salmonella spp. and E. coli O157:H7 were not detected in the pollen samples. The mean value of the dry matter, ash, titratable acid, pH, ascorbic acid, total carbohydrate, protein, fat, total phenolic content, FRAP, and TEAC of the bee pollen samples were 76.760%, 1.993%, 3.376%, 4.52, 32.047 mg/100g, 5.394 mg/g, 27.609 mg/g, 5.519%, 4.664 mg GAE/g, 29.644 µmol Trolox/g, and 1.736 µmol Trolox/g, respectively. The color values of the tested pollens were 56.923, 7.556, 26.456, 27.604, and 74.138 for L*, a*, b*, C*, and H*, respectively. Although the samples were collected mainly from one province (Mug˘la) of the Aegean Region (a geographical region by the Mediterranean Sea), a significant variation in the pollen compositions was observed.

Tugba Cebeci (ORCID: 0000-0001-8960-0587, Burcu Karagulle (ORCID: 0000-0002-6628-4515, Barıs Otlu (ORCID: 0000-0002-6220-0521
Investigation of prevalence, serotyping, and antibiotic resistance of Listeria mono­cytogenes in samples of meat, milk, and cheese from eastern Turkey
Untersuchung der Prävalenz, Serotypisierung, und Antibiotikaresistenz von Listeria monocytogenes in Proben von Fleisch, Milch und Käse aus der Osttürkei

The aim of the present study was to investigate Listeria monocytogenes contamination in ground meat purchased from local butchers and raw cow milk and tulum cheese samples sold in public markets to identify serotypes of the obtained isolates and examine their antibiotic-resistance profiles. We microbiologically tested 300 samples of different origins for the presence of L. monocytogenes and confirmed the isolates found using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and polymerase chain reaction, (PCR) after which they were serotyped and tested for antibiotic resistance against 8 antimicrobial agents using the disk diffusion method. L. monocytogenes was identified in 18 (6%) all of the collected samples. The serotypes of the 18 L .monocytogenes isolated in our study were 1/2b (3b) in 9 (50%), 1/2c (3c) in 4 (22.2%), 4b (4e, 4e) in 3 (16.7%), and 1/2a (3a) in 2 (11.1%) of the isolates. All iso­lates were found to be sensitive to ampicillin, erythromycin, gentamicin, chloramphenicol, penicillin, tetracycline, vancomycin, and sulfamethoxazole/trimethoprim. Although the isolates were sensitive to all commonly used antibiotics and given that L. monocytogenes serotypes were isolated in the examined samples, this pathogen should be closely monitored and its prevalence should be controlled using precautionary measures.