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1.
ACS Omega ; 9(9): 10400-10414, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38463315

RESUMO

The processing of shalgam requires the use of an appropriate processing technique due to yeast overgrowth. With advancements in processing technology, high hydrostatic pressure (HHP) as nonthermal and nonchemical preservation has gained attention for its potential. Response surface methodology with the Box-Behnken experimental design was used to make sense of the effects of HHP parameters, namely, pressure (100-500 MPa), temperature (20-40 °C), and time (5-15 min), on microbial and physicochemical factors (pH, total soluble solids, titratable acidity, bioactive compounds, color values). The reduction in the counts of total mesophilic aerobic bacteria, lactic acid bacteria, and yeast-mold increased proportionally with the increase of all pressure levels, application temperatures, and pressurization times (p < 0.05). Stability was maintained in pH, total solubility, and some color parameters such as L*, a*, ΔE, yellow color tone, and red color tone. All findings of the bioactive components (phenolic content, flavonoid content, antioxidant activity, and monomeric anthocyanin content) in the RSM design showed a significant change only in proportion to the square of time (p < 0.05). The optimum pressurization parameter combination of shalgam was determined as a pressure of 367 MPa, temperature of 31.9 °C, and process time of 10.5 min. Under these conditions, values of yeast and mold (Y&M) reduction, total flavonoid content (TFC), total monomeric anthocyanin contents (TMACs), titratable acidity (TA), and reducing sugar content (RSC) were obtained as 4.30 log cfu/mL, 192.89 mg QE/100 mL, 11.88 mg/100 mL, 2.41 glactic acid/L, and 6.78 mg/100 mL, respectively. In particular, the findings in the basic color parameters proved that there was no significant change in the saturated red color of the shalgam. Gallic acid, caffeic acid, chlorogenic acid, catechin, cyanidin-3-O-glucoside, malvidin-3-O-glucoside, and peonidin-3-O-glucoside derivatives are dominant phenolic and anthocyanin compounds, which are frequently found in turnip plants. No important losses in bioactive components were observed, despite changes in pressure and temperature parameters. The HHP method can be suggested to have great potential in the processing of shalgam (fermented turnip beverage) in terms of its ability to maintain the flavors, colors, and nutrients, in addition to ensuring microbiological safety when compared to other preservation methods.

2.
Food Sci Biotechnol ; 33(3): 625-635, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38274192

RESUMO

In this study, Streptococcus thermophilus and Lactobacillus bulgaricus strains from traditional Turkish yoghurts were isolated, identified by 16S rRNA sequencing and genotypically 14 S. thermophilus and 6 L. bulgaricus strains were obtained as distinct strains by MLST analysis. Lactic acid production levels of the L. bulgaricus strains were higher than S. thermophilus strains. HPLC analysis showed that EPS monosaccharide composition of the strains mainly consisted of glucose and galactose. In general, all strains were found to be susceptible for antibiotics, except some strains were resistance to gentamicin and kanamycin. Apart from two strains of S. thermophilus, all strains displayed strong auto-aggregation level greater than 95% at 24 h incubation. S. thermophilus strains showed higher cell surface hydrophobicity than L. bulgaricus strains. This study demonstrated the isolation, identification, genotypic discrimination and techno-functional features of wild type yoghurt starter cultures which can potentially find place in industrial applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01366-2.

3.
J Microbiol Methods ; 217-218: 106884, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38158082

RESUMO

Fourier transform infrared spectroscopy (FTIR) is an alternative microbial identification technique due to its faster analysis times and lower cost compared to molecular methods. In this study, forty-three fungal strains isolated from different Turkish traditional mold-ripened cheeses representing nine different Penicillium species (P. roqueforti, P. corylophilum, P. before, P. crustosum, P. spinulosum, P. rubens, P. brevicompactum, P. paneum, and P. solitum) were analyzed by using FTIR HTS-XT (High Throughput Screening Extension) method in the 4000-400 cm-1 wavenumber range. The spectra of the isolates were evaluated, and the chemical structures corresponding to the fungus-specific spectral regions were determined as fatty acids (3600-2800 cm-1), amide I and amide II of proteins and peptides (1740-1500 cm-1), polysaccharides (1200-900 cm-1) and carbohydrates (900-600 cm-1). The isolates were grouped according to the hierarchical clustering analysis (HCA) by applying chemometrics combined with FTIR spectroscopy. Results showed that FTIR spectroscopy has a high capability for rapid determination of cheese fungi based on their FTIR spectra.


Assuntos
Queijo , Queijo/microbiologia , Fungos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise por Conglomerados , Amidas
4.
Prep Biochem Biotechnol ; 53(4): 454-463, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35848985

RESUMO

The development of new starter cultures is a crucial task for the food industry to meet technological requirements and traditional products are important reservoirs for new starter cultures. In this respect, this study aimed to isolate, identify, and determine the technological characteristics of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains originated from traditional yogurt samples. Genotypic discrimination of 200 isolates revealed the presence of distinct 19 S. thermophilus and 11 Lb. delbrueckii subsp. bulgaricus strains as potential starter cultures. Strain-specific properties determined the acidification capacity of the yogurt starter cultures and a higher acidification capacity was observed for S. thermophilus strains compared to Lb. delbrueckii subsp. bulgaricus strains. Proteolytic activity was found between 0.012-0.172 and 0.078-0.406 for S. thermophilus and Lb. delbrueckii subsp. bulgaricus strains, respectively. 4 of S. thermophilus and 3 of Lb. delbrueckii subsp. bulgaricus strains were found resistant to all tested bacteriophages. The antibiotic susceptibility tests of the isolates revealed that a very low antibiotic resistance was observed for the yogurt starter cultures. Finally, the growth kinetics of selected strains were determined and the maximum specific growth rate of selected S. thermophilus and Lb. delbrueckii subsp. bulgaricus was calculated as 0.527 h-1 and 0.589 h-1, respectively.


Assuntos
Lactobacillus delbrueckii , Iogurte , Fermentação , Cinética , Indústria Alimentícia
5.
Foods ; 10(3)2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33804465

RESUMO

This study aimed to evaluate the influence of sourdough fermentation on the estimated glycemic index (eGI), in vitro starch digestibility, and textural and sensory properties of eight experimentally prepared sourdough breads. Wheat and whole wheat flour bread samples were produced under different fermentation conditions (25 °C and 30 °C) and fermentation methods (type-1 and type-2). In type-1 fermentation, sourdough was obtained via spontaneous fermentation. Indigenous strains (Lactobacillus brevis ELB99, Lactiplantibacillus plantarum ELB75, and Saccharomyces cerevisiae TGM55) were used for type-2 fermentation. Fermentation type and temperature significantly affected eGI, the hydrolysis index (HI), the starch fraction, and the textural properties of the samples (p < 0.05). The resistant starch (RS) content increased after fermentation, while rapidly digestible starch (RDS), HI, and eGI decreased. RS values were significantly higher in type-2 than in type-1 at the same temperature for both flour types (p < 0.05). At 25 °C, RS values were higher in both fermentation types. In the white flour samples, eGI values were in the range of 60.8-78.94 and 62.10-78.94 for type-1 and type-2, respectively. The effect of fermentation type on eGI was insignificant (p < 0.05). In the whole flour samples, fermentation type and temperature significantly affected eGI (p < 0.05). The greatest eGI decreases were in whole wheat sourdough bread at 30 °C using type-2 (29.74%). The 30 °C and type-2 samples showed lower hardness and higher specific volume. This study suggests that fermentation type and temperature could affect the eGI and the textural and sensory properties of sourdough bread, and these factors should be considered during bread production. The findings also support the consumption of wheat and whole wheat breads produced by type-2 fermentation due to higher RS and slowly digestible starch (SDS) and lower RDS and eGI values.

6.
Food Chem ; 354: 129495, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33743448

RESUMO

There is a necessity for rapid, robust, easy, accurate and cost-effective methodologies for the quality control of essential oils from medicinal and aromatic plants. Rosa damascena essential oil is a high-value natural product with its unique quality properties and economic importance. This research evaluated the capability of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and gas chromatography-mass spectrometry (GC-MS) techniques combined with chemometrics for determination of the authenticity of R. damascena essential oil. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were successfully employed with 100% accuracy for discrimination of authentic R. damascena essential oil samples from fraudulent commercial samples. Consistent results were obtained by FTIR, Raman and GC-MS techniques. Two of twenty commercial samples were determined as authentic R. damascena essential oil samples using the three analytical techniques. Findings showed that FTIR and Raman spectroscopy combined with chemometrics could be used as reliable, robust, rapid, accurate and low-cost analytical techniques for quality evaluation of R. damascena essential oil.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas , Óleos Voláteis/química , Rosa/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Análise por Conglomerados , Análise de Componente Principal , Rosa/metabolismo , Compostos Orgânicos Voláteis/análise
7.
J Biosci Bioeng ; 130(5): 450-456, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32782196

RESUMO

The aim of this study was to characterize the biodiversity of lactic acid bacteria (LAB) isolated from spontaneously-fermented hull-less barley sourdough and to determine its technological properties. Biodiversity was investigated by analysis of colonies isolated from sourdough on four different agar media. Of the 80 isolates, 67 were rapidly pre-identified as LAB using Fourier transforms infrared spectroscopy (FTIR). As a result of cluster analysis, 32 lactic acid bacteria chosen from different branches were identified. According to the polymerase chain reaction (PCR) results, 9 different species were identified: Pediococcus (dominant species), Lactobacillus curvatus, Lactobacillus brevis, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus musae, Lactobacillus paralimentarius, Leuconostoc mesenteroides and Lactobacillus equigenerosi. The most species and strain diversity among the media was determined in ModMRS environment. Unlike other studies about hull-less barley, Lactobacillus equigenerosi was identified in this study. LABs were identified with salt and acid tolerance. Generally, different levels of antibacterial activity in these species were shown against (rope spoilage) food borne pathogens. The greatest antimicrobial effect was observed for Pediococcus acidilactici SAB26, Lactobacillus plantarum SAB15 and Pediococcus acidilactici SAB13 compared to the other strains. Pediococcus species were found to have the highest antifungal effect against Penicillium carneum, Aspergillus flavus and A. niger. The phytase activity of LAB, which increases mineral bioavailability, was observed to be highest in Lactobacillus plantarum, Pediococcus pentosaceus, and Leuconostoc mesenteroides.


Assuntos
Biodiversidade , Fermentação , Microbiologia de Alimentos , Hordeum/metabolismo , Hordeum/microbiologia , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Reação em Cadeia da Polimerase
8.
Artigo em Inglês | MEDLINE | ID: mdl-30882282

RESUMO

The purpose of this study was to measure acrylamide (AA) levels and selected parameters of different traditional Turkish coffees. AA, 5-hydroxymethylfurfural (HMF), total reducing sugar, protein, pH, moisture, dry matter (DM) as well as ash, caffeine and soluble solids content (SSC) in DM, L*, a*, b* colour parameters of coffee samples were determined and the correlation between AA level and these parameters were investigated. A total of 36 coffee samples (20 Turkish, 8 Dibek and 8 Terebinth coffee) from the Turkish market were examined. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated for the detection and quantitation of AA in coffee samples. The calibration curve was linear (R2 ≥ 0.999) over the range of 30-1000 µg kg-1. The limit of detection (LOD) and limit of quantification (LOQ) were found as 4.6 µg kg-1 and 15.5 µg kg-1, respectively. The amounts of AA in analysed coffee samples were in the range 31.1 ± 0.6 to 323.4 ± 5.4 µg kg-1. The highest mean AA levels were found in Terebinth coffees (240.3 µg kg-1) followed by Turkish coffees (204.3 µg kg-1) and then Dibek coffees (78.6 µg kg-1). No tested Turkish coffee samples had an AA concentration above the indicative value (450 µg kg-1) for roast coffee recommended by the European Commission (EC) in 2011. In addition, a strong positive correlation was found between HMF values and AA amounts of selected coffee types.


Assuntos
Acrilamida/análise , Cafeína/análise , Café/química , Contaminação de Alimentos/análise , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Espectrometria de Massas em Tandem , Turquia
9.
Food Chem ; 277: 373-381, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30502159

RESUMO

Gelatin is widely used in gummy candies because of its unique functional properties. Generally, porcine and bovine gelatins are used in the food industry. FTIR-ATR combined with chemometrics analysis such as hierarchical cluster analysis (HCA) (OPUS Version 7.2 software), principal component analysis (PCA) (OPUS Version 7.2 software) and partial least squares-discriminant analysis (PLS-DA) (Matlab R2017b) were used for classification and discrimination of gelatin gummy candies related to their gelatin source. The spectral region between 1734 and 1528 cm-1 was selected for chemometric analysis. The potential of FTIR spectroscopy for determination of bovine and porcine source in gummy candies was examined and validated by a real-time polymerase chain reaction (PCR) method. Twenty commercial samples were tested by developed ATR-FTIR methodology and RT-PCR technique, mutually confirming and supporting results were obtained. Gummy candies were classified and discriminated in relation to the bovine or porcine source of gelatin with 100% success without any sample preparation using FTIR-ATR technique.


Assuntos
Doces/análise , Análise de Alimentos , Gelatina/química , Espectroscopia de Infravermelho com Transformada de Fourier , Animais , Bovinos , Análise por Conglomerados , Análise Discriminante , Manipulação de Alimentos , Análise de Componente Principal , Reação em Cadeia da Polimerase em Tempo Real , Suínos
10.
Food Sci Biotechnol ; 27(2): 499-508, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30263774

RESUMO

In this study, yeasts were isolated and characterized from twelve traditional sourdough samples which belongs to Black Sea and Aegean regions of Turkey. Twenty six yeast species were isolated and identified by both 26S rDNA sequencing and FTIR spectroscopy. Saccharomyces cerevisiae (50%), Torulaspora delbrueckii (40%) and Kluyveromyces marxianus (10%) were found in 12 Turkish traditional sourdough samples. S. cerevisiae was found to be the most dominant species in Aegean region while T. delbrueckii was the most frequently isolated species in Black Sea region. Some technological properties of isolated yeast species such as acidity development, resistance to NaCI and potassium sorbate, and yeast effect on bread quality were investigated. Breads were prepared by S. cerevisiae TGM38 strain demonstrated the highest bread volume compared the other yeasts used in the study. This study showed the yeast diversity and technological properties of traditional Turkish sourdough breads fermented by chosen yeast species.

11.
Food Chem ; 190: 1109-1115, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26213083

RESUMO

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.


Assuntos
Peixes/crescimento & desenvolvimento , Gelatina/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Animais , Bovinos , Análise de Componente Principal , Suínos
12.
J Food Sci Technol ; 52(10): 6465-74, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26396391

RESUMO

In this study, bioactive (total phenolic, antioxidant and antiradical activity) and rheological properties (steady and dynamic) of rose hip marmalade were investigated. Bioactive properties were determined in rose hip marmalade and extract. Extract had higher total phenolic content (38.5 mg GAE/g dry extract), antioxidant activity (124 mg AAE/g dry extract) and antiradical activity (49.98 %) than marmalade. Steady and dynamic rheological properties of the marmalade were determined at different temperature levels (5, 25 and 45 °C). Rose hip marmalade exhibited shear thinning behavior and Ostwald de Waele model best described flow behavior of the sample (R (2)  ≥ 0.9880) at different temperature levels. Consistency index and apparent viscosity values (η 50 ) at shear rate 50 s(-1) decreased with increase in temperature level. Viscoelastic properties were determined by oscillatory shear measurements and G' (storage modulus) values were found to be higher than G'' (loss modulus) values, indicating that the rose hip marmalade had a weak gel-like structure with solid-like behavior. G', G'', G (*) (complex modulus) and η* (complex viscosity) values decreased with increase in temperature level. Modified Cox-Merz rule was satisfactorily applied to correlate apparent and complex viscosity values of the rose hip marmalade at all temperatures studied.

13.
Food Res Int ; 64: 634-646, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30011698

RESUMO

In this study, natural honey was adulterated with the addition of adulterants, namely saccharose and fructose syrups at a ratio of 0%, 10%, 20%, 30%, 40% and 50% by weight. Steady, dynamic and creep tests were conducted, revealing that the changes in the flow, viscoelastic and creep behavior of natural honey were clear and remarkable. Syrup addition decreased viscosity (η), storage (G') and loss modulus (G″) values of the control honey samples. Deformation represented by the compliance (J(t)) values was more prominent in the adulterated honey samples. In addition, HPLC-RID analysis was conducted to determine major sugar composition of the adulterated samples. Pearson's correlation test indicated that there were significant (P<0.05; 0.01) correlations between sugar composition and rheology parameters, η (viscosity), K″, K⁎ (intercepts for G″ and complex modulus (G⁎), respectively) and η0 (viscosity of Maxwell dashpot), suggesting that K', K″, K⁎ and η0 could be prominent indicators for presence of saccharose or fructose syrups added in natural honey within the studied concentration levels. These results suggested that use of steady, dynamic and creep analysis would be a novel and potential approach to detect honey adulteration by fructose and saccharose syrups.

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