Aktuelle Themen

Aktuelle Themen

Aktuelle Themen

Harpreet Kaur Jambh, Ranjeet Singh, Kshitiz Kumar
Review of industrial drying of fruits and vegetables
Industrielles Trocknen von Obst und Gemüse

Fruits and vegetables are perishable in nature and need to be preserved to reduce post-harvest losses. To preserve fruits and vegetables for a longer time, drying is one of the most important and essential technique. It increases shelf life by preventing the microbial spoilage and reduction in bulk which significantly decreases the handling and storage cost. Traditionally, the perishable food items were dried in the open under the sun with the aim of preservation only without considering the quality of the product. But with the advancement of technology and increases awareness on food safety and quality, the emphasis took a shift with focus on various characteristics such as flavor, texture, functionality and nutrient value of dried product along with preservation. Various drying methods have been developed over time that is used for the drying of fruits and vegetables to get a wide range of dried products. An appropriate selection of the drying method is essential for the removal of moisture content. The development of drying technology divided into four generations from conventional to novel drying methods. In each generation, several dryers along with their operating principles, applications, advantages and disadvantages are reviewed. This paper focuses on the industrial application of each dryer for drying of various types of fruits and vegetables.

Gehalte an biogenen Aminen in Tierfutter­konserven und in zur Rohverfütterung ­bestimmter Rindermuskulatur (BARF)
Contents of biogenic amines in canned pet food and in beef-based BARF-food

In dieser Studie wurden die Gehalte an biogenen Aminen in 72 Proben von zur Rohverfütterung (BARF) bestimmtem Hundefutter aus Rindfleisch (gewolftes Fleisch in Wursthüllen abgefüllt und tiefgekühlt vertrieben) und in 45 Tierfutterkonserven für Hunde (Alleinfuttermittel mit Rind-Anteil) ermittelt. Bei 7/72 BARF-Proben, aber bei keiner Konserve war die Summe der Amine Cadaverin, Histamin, Putrescin und Tyramin über 300 mg/kg Frischmasse, was auf Verderb hinweisen würde.
Zum Vergleich der BARF-Proben und der Tierfutterkonserven wurden die Amingehalte auf Trockensubstanz bezogen. Die Gehalte an Cadaverin, Putrescin und Tyramin waren in den BARF-Proben signifikant höher als in den Tierfutterkonserven (Medianwerte 31,5 vs. 24,2 mg/kg; 74,1 vs. <5 mg/kg und 86,5 vs. 27,6 mg/kg Trockenmasse), umgekehrt wiesen die Konserven signifikant höhere Histamin- (148,5 vs. 64,5 mg/kg Trockenmasse) und Sperminkonzentrationen (111,2 vs. 68,6 mg/kg Trockenmasse) auf.
Die mikroskopisch ermittelte Keimzahl (Direkte-Epifluoreszenz-Filter-Technik) der Tierfutterkonserven war mit 6,16±0,40 log10/g signifikant niedriger als jene in den BARF-Proben (7,35±1,06 log10/g). Beim Vergleich der beiden Produktgruppen muss berücksichtigt werden, dass die Konserven mit Rind neben Rindermuskulatur auch Anteile von Nebenprodukten der Schlachtung und Komponenten nicht-tierischer Herkunft enthalten, was zu Unterschieden im Aminmuster und auch in Art und Höhe der mikrobiellen Belastung führen kann. Die Ergebnisse zeigen, dass bei diesen Produktgruppen, und insbesondere bei BARF-Futter, Verbesserungsmöglichkeiten bei der Rohstoffauswahl, der Lagerdauer und -temperatur gegeben sind.

Hilal Zeynep Sahin, Bülent Kabak
Quantification of deoxynivalenol and ­fumonisins in cereals and derived products by high-performance liquid chromatography
Quantifizierung von Deoxynivalenol und Fumonisinen in Getreide und ­Getreideprodukten mittels Hochleistungsflüssigkeitschromatographie

Mycotoxins are toxic, hazardous chemicals that affect human and animal health. The most common problem that importers are facing when importing cereals from main supplying countries is contamination with mycotoxins. The aim of the present study was to assess the presence of deoxynivalenol (DON) and fumonisins (FUM) in cereals and derived products. A total of 225 samples (60 wheat, 60 maize, 40 rice, 40 pasta and 25 maize chip) collected from Turkey were analysed by high performance liquid chromatographic (HPLC) method. The method performance was satisfactory and allowed to quantify target analytes accurately. DON was determined in 6.7% of wheat samples with a range of 158–653 µg/kg. Only two rice and two pasta samples contain trace amounts of DON, while no DON was detected in maize and maize chip products. Eleven maize samples (18.3%) contained fumonisin B1 (FB1), but levels (125–830 µg/kg) were below the European Union maximum level of 4000 µg/kg. FB1 was not detected in any wheat and rice sample, but it was detected in just one pasta and one maize chip sample. It is recommended to further monitoring both of free and modified Fusarium toxins in cereals and derived products throughout Turkey.

Elif Feyza Topdas, Memnune Sengul, Bulent Cetin
Influence of extraction methods and ­solvents on the antimicrobial activity of pickled Ferula orientalis
Extraktionsmethoden und Auswirkungen von Lösungsmitteln auf die ­antimikrobielle Aktivität von eingelegten Ferula orientalis

The aim of this study was to determine the antimicrobial effects of the essential oil and various extracts of pickled Ferula orientalis L. Two Gram (-) bacteria (Escherichia coli, Pseudomonas aeruginosa), two Gram (+) bacteria (Staphylococcus aureus, Streptococcus mutans), two yeast (Saccharomyces cerevisiae, Candida albicans), and two mold (Aspergillus niger, Penicillium roqueforti) strains were used to determine the antimicrobial effect of the extracts on different cell types. The extracts were prepared using classical and ultrasonic methods with five different solvents (water, ethanol: water, methanol: water, chloroform, and n-hexane). The essential oil was obtained by hydrodistillation. The in vitro antimicrobial assays showed that the essential oil and extracts were more effective on Gram (+) bacteria and molds. The highest antibacterial activity was exhibited against S. mutans with ultrasonic ethanol: water extract (31.25 µg mL–1). In addition, the essential oil exhibited strong inhibitory activity against A. niger (MIC: 62.5 µg mL–1) compared to the other tested microorganisms. The results showed that solvent diversity had an important effect on antimicrobial activity of all the tested microorganisms (p < 0.01) and the extraction method (classical or ultrasonic) was effective on E. coli, P. aeruginosa, C. albicans, A. niger, and P. roqueforti (p < 0.05).