Development of spectroscopic and chromatographic techniques and validation of methodologies for determination the source of gelatin in gummy candies in the scope of halal food

Gelatin is widely used in food industry due to its favorable and unique functional properties. Generally, gelatin is used as gelling, thickening and stabilizing agent. Other functional properties of gelatin can be listed as texturization, emulsification and adhesiveness. Food producers utilize from gelatin for its favorable functional properties in a wide variety of food stuffs such as gummy candies, jellies, milk desserts, marshmallows and more. Mainly porcine and bovine gelatins are produced and exports and imports of them occur around the world in order to respond to the demands of especially confectionery sector. At this point, authentication of the gelatin comes into prominence since communities including Muslims, Hindus and vegetarians have sensivity and selectivity in consumption of certain ingredients. However most of the commercial gelatin is produced from pork meat and skin since pork has been cheaper. When we consider the status in Turkey, gelatin production does not occur at a level that satisfies the demand of the industry therefore most of the gelatin is imported from other countries. In this case, control mechanisms of government should determine the origin of gelatin both in pure state and in the product. Namely, there is an essential necessity for building reliable and strong methods in order to detect the origin of commercial gelatin and detect the source of gelatin as an ingredient in food products. The objective of this thesis was to develop a rapid spectroscopic technique as an alternative method for the differentiation and authentication of gelatin sources in food products by using 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). Moreover, ATR–FTIR spectral data successfully discriminated pure bovine gelatin from mixture of bovine and porcine gelatins. Raman spectroscopic techniques combined chemometrics were successfully applied in order to determine the origin of gelatin. Raman spectroscopy and chemometrics of HCA, PCA and GADA were successfully applied for determination the source of standard gelatins (bovine, porcine). Additionally, marker peptides for standard gelatins were determined using nano LC-MS/MS study. In this thesis study, for the first time, FTIR-ATR technique combined chemometrics of HCA (hierarchical cluster analysis) and PCA (principal component analysis) were used with the aim of building a new, rapid, effective, non-destructive and cost-effective method in order to determine the origin of gelatin in gummy candies. In addition PLS-DA (partial least squares-discriminant analysis) was performed for calibration and cross-validation using Matlab programming (Matlab R2017b - MathWorks Inc., Natick, MA). Eventually, results of test samples were validated using a real-time PCR based method.