Efecto antimicrobiano de los aceites de comino negro turco

A series of five different oils from Turkish black cumin ( Nigella sativa ) used in foods mainly for their flavour, preservation and natural therapies were screened for their antibacterial effects at 0.5 %, 1.0 % and 2.0 % concentrations using the agar diffusion method against twenty four pathogenic, spoilage and lactic acid bacteria (LAB). All tested oils showed antibacterial activity against all the bacteria used in the assay. The oils at 2.0 % concentration were more effective than of the other concentrations. The most sensitive bacterium against all of the oil concentrations was Aeromonas hydrophila, while the most resistant was Yersinia enterocolitica. Generally, lactic acid bacteria had more resistance than pathogenic and spoilage bacteria against black cumin oils. Consequently, black cumin oil may be used as an antimicrobial agent in food products to prevent spoilage.Se ensayaron un total de cinco aceites diferentes de comino negro turco ( Nigella sativa L.), que se utilizan habitualmente en alimentos para darles sabor, ayudar a la conservación o por sus efectos terapéuticos, para estudiar sus propiedades antimicrobianas a concentraciones de 0.5 %, 1.0 %, y 2 %. Para ello se utilizó el método de difusión en agar, frente a veinticuatro microorganismos patógenos, causantes de alteraciones o bacterias ácido lácticas (LAB). Todos los aceites ensayados mostraron actividad antimicrobiana contra todos los microorganismos ensayados, siendo las concentraciones del 2 % las concentraciones más eficaces. Aeromonas hydrophyla fue el microorganismo mas sensible a todas las concentraciones mientras que Yersinia enterocolitica fue la más resistente. Generalmente las bacterias acido lácticas tuvieron más resistencia que los gérmenes patógenos y las bacterias que causan alteraciones. En consecuencia, el aceite de comino negro turco se puede utilizar como agente antimicrobiano en productos alimenticios para evitar su alteración

Natural food colorants and bioactive extracts from some edible flowers

Consumers’ interest in natural coloring has also been growing in parallel with their consciousness of food-health relationship. Anthocyanin based colorings bear antioxidative features renders this group of colorings more attractive. In this research, heat stabilizations and some bioactive properties of anthocyanin-based extracts (ABE) obtained from corn poppy, tulip, rose and roselle, were determined. While the greatest amount of phenolic substance is determined in the tulip (113.76 mg gallic acid equivalents (GAE) g-1 dry extract), the greatest amount of anthocyanin is in the corn poppy (405.22 mg cy-3-glucoside g-1 dry extract). Of the extracts, the corn poppy, with a level 55.85 μg mL-1, has been determined to have the highest antiradical capacity, and the tulip, with a level of 63.44 mg of ascorbic acid equivalent (AAE) g-1 dry extract has been determined to have the highest antioxidant activity. While there has been no antimicrobial effect of corn poppy extract observed on any microorganism, roselle extracts have been found to display high antimicrobial activity. Heat stability of ABEs were investigated in buffer solution pH 3.5. The flowers have high bioactive properties. There are studies planned on the use as coloring in various nutrients of the flower extracts with high bioactivity

Preživljavanje bakterije Listeria monocytogenes u Ayranu, tradicionalnom turskom fermentiranom napitku

Ayran is a traditional fermented dairy product produced by mixing milk or yoghurt, water and salt. In this study, survival of Listeria monocytogenes 1/2b was investigated in Ayran samples. For that purpose, Ayran samples produced from yoghurt (Group A and B) or directly form milk (Group C and D) were contaminated with 1 % concentration of 7 (A1, B1, C1 and D1 samples) or 5 (A2, B2, C2 and D2 samples) log cfu/mL of L. monocytogenes. So, eight different samples of Ayran were produced and stored at 4 ºC (Group A and C) or 20 ºC (Group B and D) for 21 days. According to the obtained results, there was no significant change in the number of viable cells of L. monocytogenes 1/2b in samples A1, A2, C1 and C2 after 21 days of the storage period. However, L. monocytogenes 1/2b cells of B1 and B2 samples were completely inhibited after 5 days of storage at 20 ºC. Similarly to that, L. monocytogenes 1/2b cells in samples D1 and D2 were also completely inhibited after 3 days of the storage. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus viable cell counts were between 103-107 cfu/mL in all of the samples. Consequently, Ayran contaminated with L. monocytogenes may contribute to a risk for public health. But, due to low pH of approximately ≤3.90, Ayran is relatively safe from the risk of L. monocytogenes.Ayran je tradicionalni fermentirani mliječni proizvod koji se dobiva miješanjem mlijeka ili jogurta, te vode i soli. U ovom je istraživanju ispitivano preživljavanje soja Listeria monocytogenes 1/2b u uzorcima Ayrana. U tu su svrhu proizvedeni uzorci Ayrana iz jogurta (skupina A i B) ili izravno iz mlijeka (skupina C i D) te kontaminirani dodatkom 1 % kulture soja L. monocytogenes 1/2b u koncentraciji 7 (uzorci A1, B1, C1 i D1) ili 5 (uzorci A2, B2, C2 i D2) log cfu/mL. Time je proizvedeno ukupno 8 različitih uzoraka Ayrana koji su čuvani 21 dan na 4 °C (skupina A i C) odnosno na 20 °C (skupina B i D). Dobiveni rezultati pokazali su da u uzorcima A1, A2, C1 i C2 broj živih stanica soja L. monocytogenes 1/2b nije bio promijenjen na završetku skladištenja. Međutim, stanice L. monocytogenes u uzorcima B1 i B2 bile su potpuno inhibirane na kraju petog dana skladištenja na 20 °C. Slično tomu, u uzorcima D1 i D2 su stanice dodane kulture soja L. monocytogenes 1/2b također bile inhibirane nakon tri dana skladištenja. Pritom je broj živih stanica jogurtne kulture sastavljene od vrsta Streptococcus thermophilus i Lactobacillus delbrueckii ssp. bulgaricus u svim uzorcima bio između 103-107 cfu/mL. Prema tome, Ayran kontaminiran bakterijom L. monocytogenes može uzrokovati rizik za zdravlje potrošača. Međutim, zbog relativno niskog pH koji se kreće ispod 3,90, Ayran je relativno siguran proizvod kad se radi o prisustvu bakterijske vrste L. monocytogenes

Antifungalna aktivnost propolisa u četiri vrste voćnih sokova

Fruit juices and soft drinks are targets for spoilage yeasts, moulds and bacteria. The aim of this study is to examine the antifungal effect of ethanolic extract of Turkish propolis (EETP) treatments in four nonpasteurized fruit juices including apple, orange, white grape and mandarin against 6 different yeasts isolated from the corresponding spoiled juices. These isolated yeasts include: Candida famata, C. glabrata, C. kefyr, C. pelliculosa, C. parapsilosis and Pichia ohmeri. Minimum Inhibitory Concentration (MIC) ranges were determined responding to the National Committee for Clinical Laboratory Standards (NCCLS) M27-A that were slightly modified with broth microdilution method. In this study, the presence of propolis in apple (pH=3.9), orange (pH=3.7), white grape (pH=3.8) and mandarin (pH=3.4) juices ranging from 0.01 to 0.375 mg/mL inhibited the growth of all spoilage yeasts at 25 °C. MIC ranges of propolis were 0.02–0.375, 0.04–0.375, 0.01–0.185, 0.02–0.185 and 0.04–0.375 mg/mL in mandarin, apple, orange, white grape juices and RPMI medium, respectively. MIC ranges of Na benzoate, which was used as positive control, were 80–320, 80–320, 40–640, 40–80 and 320–1280 μg/mL in mandarin, apple, orange, white grape and RPMI medium as blank control, respectively. In terms of MIC ranges, propolis showed greater antifungal activity than Na benzoate. As a result, propolis had significant antimicrobial activity against the yeast isolates from spoiled fruit juices. It was concluded that propolis is worthy to study further as a natural preservative for foods prone to fungal spoilage.Voćni sokovi i negazirana pića podložni su kvarenju u prisutnosti kvasaca, plijesni i bakterija. Svrha je ovog istraživanja ispitati antifungalni učinak etanolnog ekstrakta turskog propolisa (ETTP) u nepasteriziranom soku jabuke, naranče, bijeloga grožđa i mandarine na 6 različitih sojeva kvasca izoliranih iz pokvarenih sokova. Izolirani su sojevi kvasca Candida famata, C. glabrata, C. kefyr, C. pelliculosa, C. parapsilosis i Pichia omeri. Minimalna inhibicijska koncentracija (MIC) određena je prema standardima nacionalnog odbora za kliničke laboratorije (NCCLS) M27-A, neznatno modificiranih metodom mikrodilucije bujona. Prisutnost propolisa u soku jabuke (pH=3,9), naranče (pH=3,7), bijeloga grožđa (pH=3,8) i mandarine (pH=3,4) u rasponu od 0,01 do 0,375 mg/mL inhibirala je rast svih sojeva kvasca na temperaturi od 25 °C. MIC propolisa u soku mandarine iznosila je 0,02-0,375, u soku jabuke 0,04-0,375, u soku naranče 0,01-0,185, u soku bijeloga grožđa 0,02-0,185 te u RPMI mediju 0,04-0,375 mg/mL. MIC natrijeva benzoata, primijenjenog kao pozitivna kontrola, iznosila je 80-320 u soku mandarine, 80-320 u soku jabuke, 40-640 u soku naranče, 40-80 u soku bijeloga grožđa i 320-1280 μg/mL u RPMI mediju korištenom za slijepu probu. Propolis je imao značajnu antimikrobnu aktivnost na sojeve kvasca izoliranih iz pokvarenih voćnih sokova. Predloženo je daljnje istraživanje propolisa kao prirodnog konzervansa hrane podložne kvarenju u prisutnosti kvasaca

Insecticidal Activity of the Essential Oils from Different Plants Against Three Stored-Product Insects

This study was conducted to determine the insecticidal activity of essential oils from oregano, Origanum onites L. (Lamiales: Lamiaceae), savory, Satureja thymbra L. (Lamiales: Lamiaceae), and myrtle, Myrtus communis L. (Rosales: Myrtaceae) against three stored-product insects. Essential oils from three species of plants were obtained by Clevenger-type water distillation. The major compounds in these essential oils were identified using gas chromatography-mass spectrometry and their insecticidal activity was tested against adults of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), the Indian meal moth Plodia interpunctella Hübner (Lepidoptera: Pyralidae) and the bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae). While the major compound found in oregano and savory was carvacrol, the main constituent of the myrtle was linalool. Among the tested insects, A. obtectus was the most tolerant species against the essential oils. However, the insecticidal activity of the myrtle oil was more pronounced than other oils tested against A. obtectus adults. The essential oils of oregano and savory were highly effective against P. interpunctella and E. kuehniella, with 100% mortality obtained after 24 h at 9 and 25 µl/l air for P. interpunctella and E. kuehniella, respectively. LC50 and LC99 values of each essential oil were estimated for each insect species