A rapid spectroscopic method for the identification of the filamentous fungi isolated from Turkish traditional mold-ripened cheeses.

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.

Microencapsulation of olive mill wastewater in Saccharomyces cerevisiae cells by spray drying and in vitro bioaccessibility of phenolic compounds.

Olive-mill wastewater (OMW), a by-product with high biological value and rich in phenolic compounds, is converted into spray-dried powders by using baker's yeast cells (YCs) as the carrier material. The encapsulation of OMW into YCs was also confirmed by Fourier transform infrared spectroscopy (FT-IR) analysis. The encapsulation yield (%) of powders for OMW phenolics was determined as 5.42 ± 0.33 and 4.02 ± 0.01% in YC microparticles non-treated and treated with high-pressure homogenization (HPH), respectively. The distorted structure of YCs, observed in scanning electron microscopy images, reduced the retention of OMW phenolics by YCs. HPH application made water removal easier, and the moisture content of YC-OMW powders was reduced from 5.13 to 3.72%. Compared to free OMW, the bioaccessibility indices (BI%) of individual phenolics were increased through yeast encapsulation, at the end of the intestinal stage, hydroxytyrosol and oleuropein could still be detected in encapsulated samples (BI% of 14-25 and 124-189%), but not in free OMW. Thus, YCs could be considered suitable encapsulating agents and show promising characteristics for technological application.

Encapsulation of Lactobacillus plantarum ELB90 by electrospraying in a double emulsion (W1/O/W2) loaded alginate beads to improve the gastrointestinal survival and thermal stability.

BACKGROUND: In the present study, the Lactobacillus plantarum ELB90 was encapsulated in double emulsion (W1/O/W2) loaded alginate beads (emulbeads) by electrospraying and compared with emulsion-free control beads. The viability of encapsulated and free cells was assessed by exposing them to thermal processing (65 °C for 30 min and 72 °C for 3 min) and simulated gastrointestinal conditions. The beads were characterized by optical, scanning electron, fluorescence, and confocal laser scanning microscopy, as well as Fourier transform infrared and gel strength analysis. RESULTS: After the intestinal stage of digestion, the survival rate of free bacteria was 38% [3.70 log colony-forming units (CFU) g-1 ], only increased to 43% and 53% for bare and chitosan-coated control beads, and it elevated the survival rate to 75% and 84% (8.70 log CFU g-1 ) for bare and chitosan-coated emulbeads, respectively. The presence of inulin increased gastrointestinal viability only in uncoated emulbeads. The bacteria loaded in emulbeads retained greater viability (5.90-6.90 log CFU g-1 ) against thermal treatment, compared to control beads (2.07-4.10 log CFU g-1 ) and free bacteria (2.57-3.11 log CFU mL-1 ). Encapsulation of L. plantarum ELB90 only in emulsion-free beads may not be appropriate for providing thermal stability. Inulin addition and chitosan-coating of the beads increased the size, and emulbeads presented smoother surfaces compared to emulsion-free beads. CONCLUSION: The contribution of a double emulsion into the gel matrix of electrosprayed alginate beads exhibited enhanced protection for probiotic bacteria that could be useful for the development of functional foods. © 2023 Society of Chemical Industry.

Low-Fat Salad Dressing as a Potential Probiotic Food Carrier Enriched by Cold-Pressed Tomato Seed Oil By-Product: Rheological Properties, Emulsion Stability, and Oxidative Stability.

This study aims to investigate the potential of the use of cold-pressed tomato seed oil by-products in a low-fat salad dressing as potential probiotic food carriers to improve the oxidative stability and emulsion stability as well as the rheological properties. The low-fat salad dressing emulsions were formulated with cold-pressed tomato seed by-product (TBP) and Lactobacillus plantarum ELB90. The optimum low-fat salad dressing formulations found were determined as 10 g/100 g oil, 0.283 g/100 g xanthan, and 2.925 g/100 g TBP. The samples prepared with the optimum formulation (SD-O) were compared with the low-fat control salad dressing sample (SD-LF) and the high-fat control salad dressing sample (SD-HF) based on the rheological properties, emulsion stability, oxidative stability, and L. plantarum ELB90 viability. The sample SD-O showed shear-thinning, viscoelastic solid, and recoverable characters. The sample SD-O showed higher IP and ΔG ++ and lower ΔS ++ values than those of the control samples. After 9 weeks of refrigerated storage, viable L. plantarum ELB90 cell counts of salad dressing samples were counted as 7.93 ± 0.03, 5.81 ± 0.04, and 6.02 ± 0.08 log cfu g-1 for SD-O, SD-LF, and SD-HF, respectively. This study showed that TBP could be successfully used in a low-fat salad dressing as a potential probiotic carrier.

The effect of invertase concentration on quality parameters of fondant.

Fondant is a saturated sugar solution which is a paste- or cream-like heterogeneous system consisting of a solid phase (saccharose crystals), a liquid phase (saturated saccharose solution and glucose/invert sugar) and a gaseous phase. Fondant is used as a filling material and as a coating material for pastry, confectionery and chocolate products. Therefore, mechanical properties are important for both machinability and sensory properties of the fondant. In the present study, the invertase enzyme was added at different concentrations (0.1-0.5%) to investigate its effect on the textural and rheological properties of the fondant during the storage period as well as on the sugar composition. After the first week of storage, the hardness of the control sample decreased from the initial value of 221.1-69.24 g and 48.22 g for the addition of 0.1 and 0.5% enzyme. G' and G″ values of the fondant decreased by treatment with invertase enzyme. The positive effect of the invertase addition to fondant was also perceived in sensory evaluation. Therefore, using invertase enzyme enabled the product having desired quality characteristics. The results of the present study highlighted that invertase enzyme can be used to soften the product improving the sensory characteristics and machinability and reducing or eliminating the crystallization of sucrose which negatively affects the quality parameters. Depending on the intended purpose of the fondant, the invertase concentration can be optimized.

Biodiversity and technological properties of yeasts from Turkish sourdough.

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.