Gonca Bilge

Identification of meat species by using laser-induced breakdown spectroscopy.

The aim of the present study is to identify meat species by using laser-induced breakdown spectroscopy (LIBS). Elemental composition differences between meat species were used for meat identification. For this purpose, certain amounts of pork, beef and chicken were collected from different sources and prepared as pellet form for LIBS measurements. The obtained LIBS spectra were evaluated with some chemometric methods, and meat species were qualitatively discriminated with principal component analysis (PCA) method with 83.37% ratio. Pork-beef and chicken-beef meat mixtures were also analyzed with partial least square (PLS) method quantitatively. Determination coefficient (R(2)) and limit of detection (LOD) values were found as 0.994 and 4.4% for pork adulterated beef, and 0.999 and 2.0% for chicken adulterated beef, respectively. In the light of the findings, it was seen that LIBS can be a valuable tool for quality control measurements of meat as a routine method.

Determination of whey adulteration in milk powder by using laser induced breakdown spectroscopy

A rapid and in situ method has been developed to detect and quantify adulterated milk powder through adding whey powder by using laser induced breakdown spectroscopy (LIBS). The methodology is based on elemental composition differences between milk and whey products. Milk powder, sweet and acid whey powders were produced as standard samples, and milk powder was adulterated with whey powders. Based on LIBS spectra of standard samples and commercial products, species was identified using principle component analysis (PCA) method, and discrimination rate of milk and whey powders was found as 80.5%. Calibration curves were obtained with partial least squares regression (PLS). Correlation coefficient (R(2)) and limit of detection (LOD) values were 0.981 and 1.55% for adulteration with sweet whey powder, and 0.985 and 0.55% for adulteration with acid whey powder, respectively. The results were found to be consistent with the data from inductively coupled plasma - mass spectrometer (ICP-MS) method.

Analysis of bakery products by laser-induced breakdown spectroscopy

In this study, we focused on the detection of Na in bakery products by using laser-induced breakdown spectroscopy (LIBS) as a quick and simple method. LIBS experiments were performed to examine the Na at 589 nm to quantify NaCl. A series of standard bread sample pellets containing various concentrations of NaCl (0.025-3.5%) were used to construct the calibration curves and to determine the detection limits of the measurements. Calibration graphs were drawn to indicate functions of NaCl and Na concentrations, which showed good linearity in the range of 0.025-3.5% NaCl and 0.01-1.4% Na concentrations with correlation coefficients (R(2)) values greater than 0.98 and 0.96. The obtained detection limits for NaCl and Na were 175 and 69 ppm, respectively. Performed experimental studies showed that LIBS is a convenient method for commercial bakery products to quantify NaCl concentrations as a rapid and in situ technique.

Identification of offal adulteration in beef by laser induced breakdown spectroscopy (LIBS)

Minced meat is the major ingredient in sausages, beef burgers, and similar products; and thus it is the main product subjected to adulteration with meat offal. Determination of this kind of meat adulteration is crucial due to religious, economic and ethical concerns. The aim of the present study is to discriminate the beef meat and offal samples by using laser induced breakdown spectroscopy (LIBS). To this end, LIBS and multivariate data analysis were used to discriminate pure beef and offal samples qualitatively and to determine the offal mixture adulteration quantitatively. In this analysis, meat samples were frozen and LIBS analysis were performed. The results indicate that by using principal component analysis (PCA), discrimination of pure offal and offal mixture adulterated beef samples can be achieved successfully. Besides, adulteration ratio can be determined using partial least square analysis method (PLS) with 0.947 coefficient of determination (R2) and 3.8% of limit of detection (LOD) values for offal mixture adulterated beef samples.

A rapid tool for determination of titanium dioxide content in white chickpea samples

Titanium dioxide (TiO2) is a widely used additive in foods. However, in the scientific community there is an ongoing debate on health concerns about TiO2. The main goal of this study is to determine TiO2 content by using laser induced breakdown spectroscopy (LIBS). To this end, different amounts of TiO2 was added to white chickpeas and analyzed by using LIBS. Calibration curve was obtained by following Ti emissions at 390.11nm for univariate calibration, and partial least square (PLS) calibration curve was obtained by evaluating the whole spectra. The results showed that Ti calibration curve at 390.11nm provides successful determination of Ti level with 0.985 of R2 and 33.9ppm of limit of detection (LOD) value, while PLS has 0.989 of R2 and 60.9ppm of LOD. Furthermore, commercial white chickpea samples were used to validate the method, and validation R2 for simple calibration and PLS were calculated as 0.989 and 0.951, respectively.

Detection and quantification of a toxic salt substitute (LiCl) by using laser induced breakdown spectroscopy (LIBS)

The use of Li salts in foods has been prohibited due to their negative effects on central nervous system; however, they might still be used especially in meat products as Na substitutes. Lithium can be toxic and even lethal at higher concentrations and it is not approved in foods. The present study focuses on Li analysis in meatballs by using laser induced breakdown spectroscopy (LIBS). Meatball samples were analyzed using LIBS and flame atomic absorption spectroscopy. Calibration curves were obtained by utilizing Li emission lines at 610nm and 670nm for univariate calibration. The results showed that Li calibration curve at 670nm provided successful determination of Li with 0.965 of R2 and 4.64ppm of limit of detection (LOD) value. While Li Calibration curve obtained using emission line at 610nm generated R2 of 0.991 and LOD of 22.6ppm, calibration curve obtained at 670nm below 1300ppm generated R2 of 0.965 and LOD of 4.64ppm.

Coffee arabica adulteration: Detection of wheat, corn and chickpea

Coffee is globally one of the most widely consumed beverages. Due to the high economic importance for the countries that produce, export and import it, its purity and detection of external impurities have been constant concern. In some cases, visual inspection is unreliable in roasted ground coffee because of resemblance in color and the texture of the cheapest fillers. The objective of this work was to evaluate the feasibility of employing Laser Induced Breakdown Spectroscopy (LIBS) for determination of coffee adulteration with chickpea, corn and wheat. For this purpose, LIBS spectra was evaluated with chemometrics methods for classification and quantification of the adulteration ratio. Coefficient of determination and limit of detection values for chickpea, corn and wheat adulteration with Coffee arabica were found as 0.996, 0.995, 0.995 and 0.56%, 0.52% and 0.45%, respectively. With LIBS, prevention of unfair competition, protection of consumers and determination of coffee quality can be achieved.

Detection of Pistacia vera Adulteration by Using Laser Induced Breakdown Spectroscopy: Detection of Pistacia vera Adulteration by Using Laser Induced Breakdown Spectroscopy

BACKGROUND Pistachio has high economic value because of its high consumption rate and consumer demand. Therefore, it has become an important target for adulteration. Green pea and spinach are the most frequently used foods for pistachio adulteration as a result of their kernel color. The present study aimed to detect pistachio adulteration with green pea and spinach samples using laser induced breakdown spectroscopy (LIBS) combined with chemometric methods. RESULTS In the first step of the study, principal component analysis was employed for qualitative analysis of pure pistachio, green pea, spinach and adulterated pistachio samples, and discrimination was achieved successfully. A score plot clearly discriminating pure pistachio, green pea and spinach samples, as well as their blind samples, was drawn using principle component (PC)1 and PC2 which explained 86.86% and 12.16% of the variance, respectively. The results showed that the calibration curve for green pea adulterated pistachio provides successful determination of adulteration level and had an R2 of 0.995 and a limit of detection (LOD) of 2.04%, whereas the calibration curve for spinach adulterated pistachio had an R2 of 0.993 and a LOD of 1.64%. CONCLUSION The results of the present study demonstrate that LIBS with the chemometric methods showed a good performance based on the high value of prediction accuracy for pistachio adulteration. This technique has high potential as a rapid method for pistachio identification and detection of adulteration.