Determination of pasteurization treatment of liquid whole egg by measuring physical and rheological properties of cake cream

The aim of this study is to determine whether liquid whole egg (LWE) is pasteurized by measuring the physical and rheological properties of cake cream. The applicability of the method was demonstrated on the creams prepared using unpasteurized and pasteurized LWE (ranging from 60 to 68 degrees C for 2 and 5 min). Foaming capacities (%) of the LWE samples were measured. Physical (specific gravity) and rheological properties (shear rate-shear stress and shear rate-viscosity) of the creams were measured. A statistically difference (decrease from 740 to 531) was found between the foaming capacity of unpasteurized and other LWE (pasteurized). The specific gravity of the control cream (containing unpasteurized LWE) was statistically found different from the other creams (containing pasteurized LWE) since it had more air bubbles. In addition, consistency index (K, decrease from 12.27 to 3.31 Pa.s(n)) and flow behavior index (n) of the control cream were found significantly different from the other creams due to the formation of less volume. A high correlation (r = .90) between the foaming capacity of LWE and consistency index of the cream was found. The results suggest that proposed method can be used as an alternative procedure to determine pasteurization treatment and foaming ability of LWE. Practical Applications Egg is one of the essential ingredients in cake batter formulation due to its ability to form foam. In recent years, liquid egg product (LEP) is more preferred thanks to its microbial safety and ease of use. On the other hand, LEP may damage the physical structure of bakery products because of the pasteurization treatment in LEP process. Pasteurization process may lead to a disruptive effect on foaming functions of egg proteins, which is ended in less volume of batter. Therefore, a practicable and reliable method is required to determine whether liquid egg is pasteurized or not. In present study, pasteurized liquid whole egg (LWE) could be determined by taking physical and rheological measurements of cake cream. In addition, a rapid and reliable analysis via rheological measurement of the cream can be proposed as an alternative to determine the foaming ability of egg

Evaluation of the weathering resistance of waterborne acrylic- and alkyd-based coatings containing HALS, UV absorber, and bark extracts on wood surfaces

In this study, tree bark extracts were assessed as functional additives to provide protection in waterborne acrylic- and alkyd-based coatings. Tree bark extracts acted as natural photostabilizers and inhibited UV degradation with high UV absorption capacity. The coating systems comprising bark extracts were compared to the control coating groups comprising ultraviolet light absorbers (UVA) of the hydroxyphenyl-s-triazine (HPT) for acrylic and nonbasic amino ether (NOR) hindered amine light stabilizers (HALS) for alkyd. Scots pine surfaces coated with acrylic and alkyd coatings were exposed to artificial weathering for 2016 h. Three different trees (maritime pine, alder and Calabrian pine) with high antioxidant activity and phenol content were used for this purpose. The chemical structure of acrylic and alkyd coating systems was also examined using ATR-FTIR spectroscopy. The weathering resistance of coating systems containing extracts was evaluated in terms of their color changes and surface roughness through macroscopic evaluation, and they were compared to commercial UV absorber. The lowest color change was observed in the alkyd-based coatings with the bark extract. For the alkyd coatings, the color change ( increment E) in the control samples was 24.85, whereas it was found to be 4.68, 5.92 and 7.80 in the test samples containing Calabrian pine, maritime pine and alder bark, respectively. However, color stabilization of the acrylic coatings with UV absorber was found to be much better than the acrylic coatings with extracts. The alkyd coating systems with extracts did not exhibit the same performance for surface roughness. The alkyd coating with the UV absorber provided a smoother surface than that with bark extracts. The acrylic coatings with alder and maritime extracts provided the best results. Acrylic coating may be compatible with (Calabrian) bark extracts. According to the obtained results, it was seen that tree bark extracts in wood coating systems have a potential to substitute commercial UV absorbers as a natural product

Effects of heat-treated liquid whole egg on cake batter rheology and the quality of baked cake

The aim of the present study is to investigate the effects of heat-treated liquid whole egg (LWE) on cake batter rheology (shear rate-viscosity and shear rate-shear stress) and quality characteristics (moisture loss, color, porosity, texture, and specific volume) of baked cakes. LWE was pasteurized at different levels which were 60-68 degrees C for 2 and 5 min. Cake batter and baked cakes were prepared using both untreated and treated LWE, and rheological properties and quality characteristics were measured, respectively. Flow behavior index (n) and consistency index (K) of the control batter group were found significantly different from the treated LWE cake batters. Heat treatment of LWE showed an unfavorable effect on porosity (decrease from 59% to 49%), hardness (increase from 1.1 to 1.4 N), and specific volume (decrease from 3.6 to 3.4 cm(3)/g) of the baked cakes because of having less volume and a stiffer structure of heat-treated LWE batter

A rapid method for detection of genetically modified organisms based on magnetic separation and surface-enhanced Raman scattering

In this study, a new method combining magnetic separation (MS) and surface-enhanced Raman scattering (SERS) was developed to detect genetically modified organisms (GMOs). An oligonucleotide probe which is specific for 35 S DNA target was immobilized onto gold coated magnetic nanospheres to form oligonucleotide-coated nanoparticles. A self assembled monolayer was formed on gold nanorods using 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) and the second probe of the 35 S DNA target was immobilized on the activated nanorod surfaces. Probes on the nanoparticles were hybridized with the target oligonucleotide. Optimization parameters for hybridization were investigated by high performance liquid chromatography. Optimum hybridization parameters were determined as: 4 mu M probe concentration, 20 min immobilization time, 30 min hybridization time, 55 degrees C hybridization temperature, 750 mM buffer salt concentration and pH: 7.4. Quantification of the target concentration was performed via SERS spectra of DTNB on the nanorods. The correlation between the target concentration and the SERS signal was found to be linear within the range of 25-100 nM. The analyses were performed with only one hybridization step in 40 min. Real sample analysis was conducted using Bt-176 maize sample. The results showed that the developed MS-SERS assay is capable of detecting GMOs in a rapid and selective manner

Glucose isomerase production on a xylan-based medium by Bacillus thermoantarcticus

Effects of medium components on intracellular glucose isomerase (GI) production were investigated by Bacillus thermoantarcticus. The highest GI activity was obtained as 1630 U dm(-3) in the medium containing (g dm(-3)): 10.6, birchwood-xylan: 5.6, yeast extract: 5.9 (NH(4))(2)SO(4) at T = 55 C in 33 cm(-3) shake-flasks. When birchwood-xylan was replaced with oat spelt- or beechwood-xylan, GI activity decreased to 1372 and 1308 U dm(-3). respectively. Effects of pH at uncontrolled-pH (pH(UC) = 6.0) and controlled-pH (pH(C) = 6.0) operations, and oxygen transfer at the all, inlet rate of 0.5vvm and agitation rates of 300, 500 and 700 min(-1), were investigated in 3.0 dm(-3) bioreactor system with 1.65 dm(3) working Volume in the designed medium. The highest GI activity was attained at 500 min(-1), 0.5 vvm, pH(UC) = 6 as 1840 U dm(-3) where cell concentration was 2.3 g dm(-3). The use of agricultural waste xylan, as the carbon source resulted in concomitant production of xylanase and GI. The highest xylanase activity was attained as 9300 U dm(-3) at 500 min(-1) and 0.5 vvm. K(L)a varied between 0.008-0.033 s(-1) whereas the highest oxygen Uptake Fate was 0.002 mmol dm(-3) s(-1). Initially biochemical reaction limitations were effective: thereafter, mass transfer resistances became more effective

Rapid discrimination between buffalo and cow milk and detection of adulteration of buffalo milk with cow milk using synchronous fluorescence spectroscopy in combination with multivariate methods

This research paper describes the potential of synchronous fluorescence (SF) spectroscopy for authentication of buffalo milk, a favourable raw material in the production of some premium dairy products. Buffalo milk is subjected to fraudulent activities like many other high priced foodstuffs. The current methods widely used for the detection of adulteration of buffalo milk have various disadvantages making them unattractive for routine analysis. Thus, the aim of the present study was to assess the potential of SF spectroscopy in combination with multivariate methods for rapid discrimination between buffalo and cow milk and detection of the adulteration of buffalo milk with cow milk. SF spectra of cow and buffalo milk samples were recorded between 400-550 nm excitation range with Delta lambda of 10-100 nm, in steps of 10 nm. The data obtained for Delta lambda = 10 nm were utilised to classify the samples using principal component analysis (PCA), and detect the adulteration level of buffalo milk with cow milk using partial least square (PLS) methods. Successful discrimination of samples and detection of adulteration of buffalo milk with limit of detection value (LOD) of 6% are achieved with the models having root mean square error of calibration (RMSEC) and the root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP) values of 2, 7, and 4%, respectively. The results reveal the potential of SF spectroscopy for rapid authentication of buffalo milk

Raman spectroscopy coupled with chemometric methods for the discrimination of foreign fats and oils in cream and yogurt

The adulteration of milk fat in dairy products with cheaper non-milk based fats or oils is frequently encountered in the dairy industry. In this study, Raman spectroscopy with chemometric was used for the discrimination of foreign fats and oils in milk cream and yogurt. Firstly, binary mixtures of cream and oils (corn and sunflower oil), and vegetable fat blends which are potentially or currently used by the dairy industry were prepared. All fat or oil samples and their binary mixtures were examined by using Raman spectroscopy. Then, fat content of skim milk was adjusted to 3% (w/w) by the milk fat, external oils or fats, and binary mixtures, and was used in yogurt production. The lipid fraction of yogurt was extracted and characterized by Raman spectroscopy. The spectral data were then pre-processed and principal component analysis (PCA) was performed. Raman spectral data showed successful discrimination for about the source of the fats or oils. Temperature effect was also studied at six different temperatures (25, 30, 40, 50, 60 and 70 °C) in order to obtain the best spectral information. Raman spectra collected at higher temperatures were more intense. Obtained results showed that the performance of Raman spectroscopy with PCA was very promising and can be expected to provide a simple and quick way for the discrimination of foreign fats and oils in both milk cream and yogurt. Fermentation and yogurt processing affected clustering of fat samples by PCA, probably depending on some lipolysis or production of new products that can affect the Raman scattering. However, those changes did not affect differentiation of samples by Raman spectroscopy. Keywords: Chemometric, Milk cream adulteration, Raman spectroscopy, Temperature, Yogurt adulteratio