Muhammet Arici

Some characteristics of Lactobacillus isolates from infant faeces

In this research, 21 strains of lactobacilli were isolated from newborn infant faeces. Lactobacillus rhamnosus (seven strains), L. paracasei ssp. paracasei (four strains), L. fermentum (four strains), L. buchneri (two strains), L. brevis (one strain), L. curvatus (one strain) and Lactobacillus sp. (two strains) isolated from infant faeces were analysed for acid production, antibiotics resistances, H2S productions and antimicrobial activities. Inhibition activity of bacteriocins and/or bacteriocin-like substances of the lactobacilli against some food contaminants and pathogenic bacteria (Escherichia coli, Staphylococcus aureus ATCC 28213, S. aureus ATCC 2392, Yersinia enterocolitica and Bacillus cereus) were determined by the agar diffusion method.

Boza: A lactic acid fermented cereal beverage as a traditional Turkish food

Consumption of lactic acid fermented foods is common in many mid-Asian, Middle East, and African countries. These products have many advantages such as destroying undesirable factors in the raw products, reducing the volume of the material, and providing a safer product. Besides improving organoleptic quality by fermentation, they are also superior in digestibility and nutritive value compared to their unfermented counterparts. Boza is a traditional Turkish beverage made by yeast and lactic acid bacteria fermentation of millet, cooked maize, wheat, or rice semolina/flour. The name, boza, in Turkish comes from the Persian word, buze, meaning millet. However, the Turks who lived in Middle Asia called this beverage bassoi. There are also similar beverages produced in East European countries (braga or brascha), the Balkans (busa), and Egypt (bouza). In the past, boza has been produced and consumed with slight differences in the recipe in the Turkish countries. Boza is made of various kinds of cereals (usually millet, maize, and wheat), but boza of the best quality and taste is made of millet flour. In the Balkans, such as Bulgaria, cocoa is also included in the boza recipe. Boza produced in Egypt has high alcohol content (up to 7% by volume) and is consumed as beer. Because of its lactic acid, fat, protein, carbohydrate, and fiber contents, it is a valuable fermented food that contributes to human nutrition.

An evaluation of Fourier transforms infrared spectroscopy method for the classification and discrimination of bovine, porcine and fish gelatins.

The objective of this research was to develop a rapid spectroscopic technique as an alternative method for the differentiation and authentication of gelatin sources in food products by using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra combined with chemometrics. Clear discrimination and classification of all the studied gelatin sources (bovine, porcine, and fish) were achieved by hierarchical cluster and principle component analysis (PCA). Amide-I (1700-1600 cm(-1)) and Amide-II (1565-1520 cm(-1)) spectral bands were used in a chemometric method. Moreover, ATR-FTIR spectral data successfully discriminated pure bovine gelatin from mixture of bovine and porcine gelatins, which is very important for the food industry. The method that we adopted could be beneficial for rapid, simple and economic determination of both gelatin presence and its origin from food products such as yogurt, ice cream, milk dessert or other gelatin containing products such as pharmaceuticals and cosmetics.

Mycoflora of hazelnut (Corylus avellana L.) and aflatoxin content in hazelnut kernels artificially infected with Aspergillus parasiticus

In this research, 30 hazelnut samples were used to determine their internal mould populations and their aflatoxin contents. The results showed that Aspergillus was the most common genus in the experimental samples (96.6% of all samples). Thirty-one% of isolates were classified as Aspergillus flavus and none of the samples contained aflatoxins. In the second part of the experiment, the kernels were inoculated with conidia of Aspergillus parasiticus and incubated at three different humidified conditions and two different temperatures for 45 days. Aflatoxin contents of the samples kept in 98% relative humidity and at 28 degrees C were higher (904.6 micrograms/kg) than that of the other samples. On the other hand, no aflatoxin was detected in the control samples that were not inoculated but kept at the same conditions.

Effect of Gamma Irradiation on Total Phenolic Contents and Antioxidant Activities of Satureja Hortensis, Thymus Vulgaris, and Thymbra Spicata from Turkey

In this study, the effect of gamma irradiation on the total phenolic content and antioxidant activity of Satureja hortensis, Thymus vulgaris, and Thymbra spicata was evaluated. Plants irradiated in a 60Co irradiator to 0, 1.2, 3.0, and 5.1 kGy at 25°C. Control and irradiated samples were extracted with methanol. The antioxidant activity of methanol extracts was determined using phosphomolybdenum assay and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. The total phenolic content in three spices was found to decrease with irradiation except at 5.1 kGy for S. hortensis. The DPPH radical scavenging activity of the extracts decreased after irradiation.

Effect of in situ exopolysaccharide production on physicochemical, rheological, sensory, and microstructural properties of the yogurt drink ayran: an optimization study based on fermentation kinetics.

Exopolysaccharide (EPS)-producing starter cultures are preferred for the manufacture of fermented milk products to improve rheological and technological properties. However, no clear correlation exists between EPS production and the rheological and technological properties of fermented milk products such as the yogurt drink ayran. In this study, 4 different strain conditions (EPS- and EPS+ Streptococcus thermophilus strains) were tested as a function of incubation temperature (32, 37, or 42°C) and time (2, 3, or 4 h) to determine the effect of culture type and in situ EPS production on physicochemical, rheological, sensory, and microstructural properties of ayran. Furthermore, we assessed the effect of fermentation conditions on amounts of EPS production by different EPS-producing strains during ayran production. A multifactorial design of response surface methodology was used to model linear, interaction, and quadratic effects of these variables on steady shear rheological properties of ayran samples and in situ EPS production levels. The physicochemical and microbiological characteristics of ayran samples altered depending on incubation conditions and strain selection. Steady shear tests showed that ayran samples inoculated with EPS+ strains exhibited pseudoplastic flow behavior. Production of ayran with EPS- strain (control sample) resulted in the lowest apparent viscosity values (η50), whereas those produced with the combination of 2 EPS+ strains yielded ayran with notably increased η50 values. We concluded that incubation time was the variable with the greatest effect on η50, consistency coefficient (K), and flow behavior index (n) values. In situ EPS production was also affected by these conditions during ayran fermentation in which strain-specific metabolism conditions were found to be the most important factor for EPS production. In addition, these findings correlated the amount of in situ EPS produced with the rheological properties of ayran. Scanning electron microscopy images of the samples showed differences in structural features, revealing a prominent network strand structure in the ayran samples inoculated with the admixture of 2 EPS-producing strains incubated at 37°C for 3 h. These results provide useful information for large-scale production of ayran by the dairy industry.

The effects of using different mustard seeds and starter cultures on some properties of hardaliye

In this research, hardaliye a traditional fermented Turkish beverage was produced by modification of traditional method and investigated for some properties.Lactobacillus sanfrancisco (LB16),Lactobacillus acetotolerans (LB21),Lactobacillus pontis (LB26),Lactobacillus paracasei ssp.paracasei (LB30) as starter cultures were added into pasteurised grape juice. Production of hardaliye using either white or black mustard seeds withLactobacillus paracasei ssp.paracasei LB30 reached to minimum pH value. It was determined that, lactobacilli which was added as starter cultures and mustard seeds had no clear effect on decrease in total sugar contents. During the 7-day fermentation period, lactic acid bacteria count in hardaliye, produced using white mustard seeds, changed from 4. 60, 4.69, 4.47 and 4.79 log CFU/ml to 4.92, 4.94, 5.90 and 6.83 log CFU/ml respectively and in the other samples, produced using black mustard seeds changed from 4.25, 4.07, 4.07 and 4.20 log CFU/ml to 6.60, 7.20, 6.54 and 6.77 log CFU/ml respectively.

Comparison of different solvent types for determination biological activities of myrtle berries collected from Turkey

In the present study, we investigated the effects of four extracting solvents (70% acetone:water (v/v), 80% ethanol:water (v/v), 80% methanol:water (v/v) and distilled water) on the total phenolic content and antiradical, antioxidant activity and antimicrobial activities of extracts of myrtle berries (Myrtus communis) collected from eight different locations in Turkey. The tested plant extracts were found to contain appreciable amounts of total phenolic contents (39.933 to 207.4 mg GAE/g dry extract) and have 1.1-diphenyl-2- picrylhydrazyl scavenging activity ranging between 6.73 and 65.6%. The antioxidant activity of the myrtle fruits was measured using the phosphomolybdenum spectrophotometric method. The highest antioxidant activity value (241.533 mg ascorbic acid equivalents /g dry extract) was observed in the methanolic extract of the fifth sample. The agar diffusion method was used to determine the antimicrobial activity of the extract samples. It was found that the methanol and acetone extracts were...

Essential Oil Compositions and Bioactivities of Thymus revolutus and Cyclotrichium origanifolium

Abstract Thymus revolutus Celak (Lamiaceae) is an endemic species in Turkey. Cyclotrichium origanifolium (Labill.) Manden & Scheng (Lamiaceae) has been widely used as a flavoring agent in soups and salads, and herbal tea in Turkey. The essential oil (EO) components, antioxidant and antimicrobial activities of the extracts and EOs of T. revolutus and C. origanifolium were examined. The EO compositions were analyzed by GC-MS. Total phenolic contents, flavanols, flavonols and antioxidant activities of the extracts were determined by spectrophotometer. Antimicrobial activity was investigated against 15 microorganisms by agar diffusion method. Carvacrol, thymol, p-cimene and borneol were predominantly found in T. revolutus EO. The C. origanifolium EO contained bicyclo[3.1.l]hepten-3-one, 2,6,6-trimethyl-,(l.α, 2.β, 5.α), pulegone and 2- cylohexen-1-ol, 1-methyl-4-(1-methylethyl),-cis as main constituents. The levels of total phenolic contents, flavanols, and flavonols of T. revolutus and C. origanifolium extracts were 38.68±2.5 and 78.57±0.6 mg gallic acid equivalent/g; 2250.06±328.0 and 610.84±13.3 mg catechin equivalent/100 g; and 1287.35±91.1 and 2712.36±20.9 mg rutin equivalent/100 g, respectively. Antioxidant activities of T. revolutus and C. origanifolium were 48.91±0.2 % and 74.86±0.3 % at 0.1 mg/mL concentration, respectively in the DPPH assay. C. origanifolium EO sat 2 % and 1 % concentrations showed antibacterial activity against tested Gram (+) bacteria but not Mycobacterium smegmatis. Both of the EOs had no inhibitory effects at 0.2 and 0.5 % concentrationson on the 15 tested microorganisms. Gram (+) bacteria found to be more sensitive to the EOs and extracts than Gram (-) bacteria in this study. The EOs and the extracts of T. revolutus and C. origanifolium could be used as natural products in many areas such as food, pharmaceutical, alternative medicine and natural therapy.

Storage Stability of Aspartame in Orange Flavored Soft Drinks

In this study, “orange flavored soft drink” samples sweetened with 100% aspartame (0.5 g/L) were stored in three different pH values and temperatures. The samples with the pH values of 2.75, 3.25, and 4.57 were kept in 20, 30, and 40°C temperatures over a period of 5 months. The remaining aspartame was determined at the 1st, 2nd, 3rd, 4th, and 5th months by HPLC. In the same pH groups, it was clearly observed that stability of aspartame decreased with increasing storage temperature. It was also determined in each of the same pH groups that aspartame stability increased as the pH value was raised from 2.75 to 4.57. Aspartame was the least stable at pH 2.75 when stored in 40°C, whereas it was the most stable at pH 4.57 and 20°C. At the end of 5th month in 40°C, stability tests could not be performed and remaining aspartame could not be determined.