Differentiation of bovine from porcine gelatines using polyclonal anti-peptide antibodies in indirect and competitive indirect ELISA

Methods for detection and quantification of gelatin from different sources

Gelatin is a water-soluble protein obtained from the collagen of various animal origins (porcine, bovine, fish, donkey, horse, and deer hide) and has diverse applications in the food, pharmaceutical, and cosmetics industries. Porcine and bovine gelatins are extensively used in food and non-food products; however, their acceptance is limited due to religious prohibitions, whereas fish gelatin is accepted in all religions. In Southeast Asia, especially in China, gelatin obtained from donkey and deer skins is used in medicines. However, both sources suffer from adulteration (mixing different sources of gelatin) due to their limited availability and high cost. Unclear labeling and limited information about actual gelatin sources in gelatin-containing products cause serious concern among societies for halal and fraud authentication of gelatin sources. Therefore, authenticating gelatin sources in gelatin-based products is challenging due to close similarities between the composition differences and degradation of DNA and protein biomarkers in processed gelatin. Thus, different methods have been proposed to identify and quantify different gelatin sources in pharmaceutical and food products. To the best of our knowledge, this systematic and comprehensive review highlights different authentication techniques and their limitations in gelatin detection and quantification in various commercial products. This review also describes halal authentication and adulteration prevention strategies of various gelatin sources, mainly focussing on research gaps, challenges, and future directions in this research area.

Characterization of gelatin-based wound dressing biomaterials containing increasing coconut oil concentrations

This study determined the influence and ideal ratios of various coconut oil (CO) amounts in gelatin (G) based-films as wound dressings since there are limited comparative studies to evaluate the sole effect of increasing CO on protein-based biomaterials. Homogenous films at G:CO ratio of 4:0,4:2,4:3,4:4 (w:w) corresponding to CO-0, CO-2, CO-3, CO-4, respectively, were obtained using solution casting. SEM showed CO caused rougher surfaces decreasing mechanical strength. However, no pores were observed in CO-4 due to bigger clusters of oil improving stretchability compared to CO-3; and durability since aging of CO-4 was >10% lower than CO-0 in aqueous media. FTIR showed triglycerides' band only in CO films with increasing amplitude. Moreover, amide-I of CO-2 was involved in more hydrogen bonding, therefore, CO-2 had the highest melt-like transition temperatures (Tmax) at ∼163 °C while others' were at ∼133 °C; and had more ideal mechanical properties among CO films. XTT showed that increased CO improved 3T3 cell viability as CO-0 significantly decreased viability at 10,50,75,100 μg/mL (p < 0.05), whereas CO-2 and CO-3 within 5-75 μg/mL and CO-4 within 5-100 μg/mL range increased viability ≥100% suggesting proliferation. All CO samples at 25 μg/mL stimulated 3T3 cell migration in Scratch Assay indicating wound healing. CO amounts mainly improved thermal and healing properties of gelatin-based biomaterial. CO-2 was more thermally stable and CO-4 had better influence on cell viability and wound healing than CO-0. Therefore, increased CO ratios, specifically 4:2 and 4:4, G:CO (w:w), in gelatin-based films can be ideal candidates for wound dressing materials.

Advances in the authentication of collagen products based on DNA technology

Collagenous products are making their way into consumer markets such as foods, nutraceuticals, cosmetics and pharmaceuticals increasingly. Collagen in a large family of proteins is ubiquitous in metazoan. The most effective way to identify biological samples including collagen is DNA technology indisputably. However, the DNA content of collagen mostly derived from connective tissue is relatively less, and commercial collagen products are usually subjected to some harsh treatments in the production process, which makes DNA damage more serious, thus tracing their origin becomes a huge challenge. At present, DNA enrichment mainly relies on silica based centrifugal columns after extraction by classical phenol chloroform method. For improving the amplification of DNA fragments, small amplicons are designed based on more stable mitochondrial genes, such as cytochrome b gene (cytb). In addition to conventional PCR for DNA amplification, some new PCR techniques have also been developed, such as DNA barcoding techniques, PCR-Southern hybridization and fluorescent PCR. These PCR techniques have their pros and cons, and are mainly used in the identification of gelatin at present. The development of a complete set of DNA authentication is of great significance for the control of collagen products quality and will contribute to sustainable development of collagen industry.

A review on proteomic and genomic biomarkers for gelatin source authentication: Challenges and future outlook

Biomarkers are compounds that could be detected and used as indicators of normal and/or abnormal functioning of different biological systems, including animal tissues and food matrices. Gelatin products of animal origin, mainly bovine and porcine, are currently under scrutiny mainly due to the specific needs of some sectors of the population related to religious beliefs and their dietary prohibitions, as well as some potential health threats associated with these products. Thus, manufacturers are currently in need of a reliable, convenient, and easy procedure to discern and authenticate the origin of animal-based gelatins (bovine, porcine, chicken, or fish). This work aims to review current advances in the creation of reliable gelatin biomarkers for food authentication purposes based on proteomic and DNA biomarkers that could be applied in the food sector. Overall, the presence of specific proteins and peptides in gelatin can be chemically analysed (i.e., by chromatography, mass spectroscopy, electrophoresis, lateral flow devices, and enzyme-linked immunosorbent assay), and different polymerase chain reaction (PCR) methods have been applied for the detection of nucleic acid substances in gelatin. Altogether, despite the fact that numerous methods are currently being developed for the purpose of detecting gelatin biomarkers, their widespread application is highly dependent on the cost of the equipment and reagents as well as the ease of use of the various methods. Combining different methods and approaches targeting multiple biomarkers may be key for manufacturers to achieve reliable authentication of gelatin's origin.

Structural and functional properties of collagen isolated from lumpfish and starfish using isoelectric precipitation vs salting out

The possibility of replacing the very time and resource demanding salting out (SO) method with isoelectric precipitation (IP) during collagen extraction from common starfish and lumpfish was investigated. The effect of IP on yield, structural and functional properties of the collagens was therefore compared with SO. Application of IP resulted in a higher or similar collagen mass yield compared with SO from starfish and lumpfish, respectively. However, the purity of collagens recovered with IP was lower than those recovered with SO. Replacing SO with IP did not affect polypeptide pattern and tropohelical structural integrity of collagen from the two resources as revealed with SDS-PAGE and FTIR analysis. Thermal stability and fibril formation capacity of collagens recovered with IP were also well preserved. Overall, the results showed that the IP can be a promising resource smart alternative for the classic SO precipitation during collagen extraction from marine resources.

Computational Modelling and Molecular Docking of Industrial Leather Enzymes

Leather is one of the widely traded commodities globally. It is a strategically important sector for the economic and industrial development of the country. However, the leather industry is perceived as a highly polluting industry. It produces huge amounts of solid and liquid wastes, and if these wastes are not properly treated and disposed of, then it tends to deteriorate the quality of soil and water, as well as cause emanations of smell and noxious gases into the surrounding. The current paper provides information about industrial leather enzymes, primarily collagenase, tannase, and lecithinase. In this study, enzymes such as collagenase, tannase, and lecithinase had a pivotal role in leather industries and their action in the bioremediation of leather effluents was further analysed and docked with a diverse range of compounds (ligands), with an optimal binding affinity score was determined. All interactions between protein ligands were depicted, which will help us with future research. Furthermore, this method can be tested practically, and other parameters can be studied in the future. Further, applications of enzymes and their hydrolyse by-products have also been highlighted in a variety of industries, including the pharmaceutical, cosmetic, agricultural, medical, and food sectors. Subsequently, this finding provides an innovative and broader goal for various sectors in terms of sustainability, stabilisation, and identifying research gaps that can guide modern industries and research scientists.

Evaluation and Characterization of Hard-Shell Capsules Formulated by Using Goatskin Gelatin

Gelatin is used as an additive in medicine, food, and cosmetics. Gelatin from goatskin is a new excipient that has not been explored by researchers, including for hard-shell capsules. The aim of this study was to evaluate and characterize the hard-shell capsules produced from goatskin gelatin. The goatskin gelatin was extracted by an acid hydrolysis method, and the functional properties were investigated. Hard-shell capsules were then produced from goatskin gelatin, evaluated, and characterized. The gelatin extracted from goatskin had 56.9% ± 0.95 clarity and a pH of 5.11 ± 0.09, 97.51% ± 1.1 protein content, 9.23% ± 0.08 water content, 0.18% ± 0.07 ash content, 2.08% ± 0.35 fat content, gel strength of 298 ± 2.64 gbloom, and viscosity of 27.33 ± 2.07 mPs. The gelatin has met the requirements to be made into hard-shell capsules. The average weight of the hard-shell capsules produced was 96.9 mg with 8.69 standard deviation. The average size of the body and cap length was 18.84 ± 0.64 mm and 10.98 ± 0.30 mm, respectively. The results of capsule evaluation and characterization were as follows: the pH was 4.82 ± 1,27, water content was 10.03 ± 0.21, disintegration time was 4.02 ± 2.09 min, and there was no microbial growth. Thus, the capsules made have met the requirements and can be produced in a large quantity.

Application of peptide biomarkers in life analysis based on liquid chromatography-mass spectrometry technology

Biomedicine is developing rapidly in the 21st century. Among them, the qualitative and quantitative analysis of peptide biomarkers is of considerable importance for the diagnosis and therapy of diseases and the quality evaluation of drugs and food. The identification and quantitative analysis of peptides have been going on for decades. Traditionally, immunoassays or biological assays are generally used to quantify peptides in biological matrices. However, the selectivity and sensitivity of these methods cannot meet the requirements of the application. The separation and analysis technique of liquid chromatography-mass spectrometry (LC-MS) supplies a reliable alternative. In contrast to immunoassays, LC-MS methods are capable of providing the analytical prowess necessary to satisfy the demands of peptide biomarker research in the life sciences arena. This review article provides a historical account of the in-roads made by LC-MS technology for the detection of peptide biomarkers in the past 10 years, with the focus on the qualification/quantification developments and their applications.

Rapid porcine detection in gelatin-based highly processed products using loop mediated isothermal amplification

Low DNA concentration recovered from highly processed products such as gelatin and gelatin-based products renders difficulty in detecting porcine contamination using conventional PCR techniques. We documented here a porcine-specific loop-mediated isothermal amplification (LAMP) to identify porcine traces in gelatin products. The porcine-specific primers were designed according to mitochondrial DNA of Cytochrome b gene sequence. Here we used two different reaction mixtures for LAMP assay (GENIE and MYRM) against the same DNA samples extracted from gelatin products and porcine-specific primers to detect the presence of porcine DNA. The porcine-specific primers were shown to be specific only to Sus scrofa against 14 DNA of other meat species. The analytical sensitivity of the LAMP assay for porcine DNA detection is 1 pg/µL using both GENIE (within 30 m) and MYRM (within 60 m) reaction mixtures. Analysis against 32 samples of gelatin products showed that five samples were found to contain porcine DNA; two samples out of six gelatin powder samples and three gelatin capsule samples out of nine. Out of these five positive samples, three were not labeled containing porcine gelatin. Overall, LAMP assay in this study showed an excellent specificity, sensitivity and rapidity in detection of porcine DNA in gelatin products.

Supplementary Information

The online version contains supplementary material available at (10.1007/s13197-020-04932-2).

Identification of bovine, porcine and fish gelatin signatures using chemometrics fuzzy graph method

Gelatin is a protein substance that is widely used in food and pharmaceutical industries. Gelatin is mainly derived from bovine and porcine sources. Fish gelatin is becoming alternative source of gelatin due to concern on health issue and religious constraints. Numerous studies for identification of gelatin sources have been reported. In this study, Fourier transform infrared (FTIR) spectroscopy was used in combination with chemometrics fuzzy autocatalytic set (c-FACS) to distinguish between bovine, porcine and fish gelatins. The gelatin spectra at Amide and 1600–1000 cm⁻¹ regions were analyzed using c-FACS and the results were compared to principal component analysis (PCA) and linear discriminant analysis (LDA). The results obtained from c-FACS method showed that each bovine, porcine and fish gelatin possessed dominant wavenumbers at 1470–1475 cm⁻¹, 1444–1450 cm⁻¹ and 1496–1500 cm⁻¹ respectively, which represent their unique signatures. Furthermore, a clear distinction for porcine gelatin was observed in coordinated FACS. The c-FACS method is rigor and faster than PCA and LDA in differentiating the gelatin sources. The novel method promises at least another chemometrics method for FTIR related analysis and the possibilities for other applications are endless.

Development and verification of a quantitative real-time PCR method to identify and quantify gelatin derived from animal hide

The species origin of hide gelatin is a crucial issue with respect to health concerns and religious restrictions. Analysis of the animal-derived ingredients of gelatin by reliable methods is necessary to ensure its authenticity. However, due to the highly processed nature of gelatin, it remains a challenge to identify gelatin end products accurately and robustly. Our study established and verified a quantitative real-time PCR (qPCR) method based on careful selection of target genes and a DNA extraction method. The middle products of the gelatin production streamline were investigated to explore the influence of each critical processing step on the method. Gelatin reference samples were used to quantify the levels of target species. Commercial gelatin commodities were surveyed to highlight the mislabeling situation. In summary, the qPCR method was demonstrated to be highly specific and sensitive, with limits of detection (LOD) of 0.1 to 1 pg/µL and gelatin LODs of 0.1% to 5% (w/w). The transition from decoction to concentrated gel was found to have the most severe effect on the qPCR. Intensification of pressure or temperature or employment of enzyme hydrolysis aggravated the DNA damage, resulting in elevated Cq values. Quantitation of gelatin products was feasible; gelatin products produced from 5% target hide and 95% matrix hide mixtures showed 2.9% to 5.2% target species. The 26% relative error for low gelatin content is acceptable for semiquantitation purposes. A market survey showed that 52.6% of the gelatin products were mislabeled as being of animal origin.

Autoclavable and Injectable Cryogels for Biomedical Applications

Prior to any clinical application, terminal sterilization of biomaterials is a critical process imposed by the Food and Drug Administration. Of all the methods available for sterilization, high-pressure steam sterilization such as autoclaving is the most widely used. While autoclave sterilization minimizes pathogen contamination, it can dramatically impact both structural and biological properties of biomaterials. It has recently been reported that injectable cryogels with shape memory properties hold great promises as 3D macroporous biomimetic scaffolds for biomedical applications including tissue engineering. In this study, the impact of autoclave sterilization on properties of a series of cryogels is measured. Unlike conventional hydrogels, cryogels made of natural polymers demonstrate a strong resilience to autoclave sterilization. This process does not alter either their macrostructural or unique physical properties including syringe injectability. The scaffolds' bioactive sites are preserved and autoclaved cryogels retain their excellent cytological compatibility post-autoclaving. Furthermore, autoclaved cryogels do not trigger a notable activation of primary murine bone marrow-derived dendritic cells suggesting a minimal risk for biomaterial-induced inflammation, which is further confirmed by an in vivo histologic analysis. In summary, these results further demonstrate the huge potential of cryogels in the biomedical field and their capacity to be translated into clinical applications.

Chemical and Chemometric Methods for Halal Authentication of Gelatin: An Overview

The issue of food authenticity has become a concern among religious adherents, particularly Muslims, due to the possible presence of nonhalal ingredients in foods as well as other commercial products. One of the nonhalal ingredients that commonly found in food and pharmaceutical products is gelatin which extracted from porcine source. Bovine and fish gelatin are also becoming the main commercial sources of gelatin. However, unclear information and labeling regarding the actual sources of gelatin in food and pharmaceutical products have become the main concern in halal authenticity issue since porcine consumption is prohibited for Muslims. Hence, numerous analytical methods involving chemical and chemometric analysis have been developed to identify the sources of gelatin. Chemical analysis techniques such as biochemical, chromatography, electrophoretic, and spectroscopic are usually combined with chemometric and mathematical methods such as principal component analysis, cluster, discriminant, and Fourier transform analysis for the gelatin classification. A sample result from Fourier transform infrared spectroscopy analysis, which combines Fourier transform and spectroscopic technique, is included in this paper. This paper presents an overview of chemical and chemometric methods involved in identification of different types of gelatin, which is important for halal authentication purposes.

Design and Validation of Short-Amplicon Length PCR Assay for the Detection of Porcine Gelatin in Commercial Candy and Marshmallow Products

Porcine gelatin has been used in many food products. To ensure the compliance of food products with halal regulations and label description, reliable analytical methods are required. In this study, Porcine-specific short amplicon-size for conventional PCR assay was developed for the detection of gelatin in commercial candy and marshmallow products. A pair of porcine-specific primers defining a 74 bp region of the mitochondrial D-loop sequence were designed. One hundred and three samples including seventy six samples from candies and twenty seven samples from marshmallow were purchased from local market in Amman, Jordan. The results revealed that seventeen samples were found to contain porcine gelatin ingredients and the rest 86 were found to be negative. Nine of the positive samples were Gelatin labeled, and eight were not identified to contain gelatin. Of these samples. Five were also labeled as Halal. So, we demonstrated that the authentication of commercial sweet ingredients using PCR assay is effective and protect consumers from being mislead due to mislabels.

Injectable Hyaluronic Acid-co-Gelatin Cryogels for Tissue-Engineering Applications

Polymeric scaffolds such as hydrogels can be engineered to restore, maintain, or improve impaired tissues and organs. However, most hydrogels require surgical implantation that can cause several complications such as infection and damage to adjacent tissues. Therefore, developing minimally invasive strategies is of critical importance for these purposes. Herein, we developed several injectable cryogels made out of hyaluronic acid and gelatin for tissue-engineering applications. The physicochemical properties of hyaluronic acid combined with the intrinsic cell-adhesion properties of gelatin can provide suitable physical support for the attachment, survival, and spreading of cells. The physical characteristics of pure gelatin cryogels, such as mechanics and injectability, were enhanced once copolymerized with hyaluronic acid. Reciprocally, the adhesion of 3T3 cells cultured in hyaluronic acid cryogels was enhanced when formulated with gelatin. Furthermore, cryogels had a minimal effect on bone marrow dendritic cell activation, suggesting their cytocompatibility. Finally, in vitro studies revealed that copolymerizing gelatin with hyaluronic acid did not significantly alter their respective intrinsic biological properties. These findings suggest that hyaluronic acid-co-gelatin cryogels combined the favorable inherent properties of each biopolymer, providing a mechanically robust, cell-responsive, macroporous, and injectable platform for tissue-engineering applications.

A Review of Gelatin Source Authentication Methods

Gelatin is a very popular pharmaceutical and food ingredient and the most studied ingredient in Halal researches. Interest in source gelatin authentication is based on religious and cultural beliefs, food fraud prevention and health issues. Seven gelatin authentication methods that have been developed include: nucleic acid based, immunochemical, electrophoretic analysis, spectroscopic, mass-spectrometric, chromatographic-chemometric and chemisorption methods. These methods are time consuming, and require capital intensive equipment with huge running cost. Reliability of gelatin authentication methods is challenged mostly by transformation of gelatin during processing and close similarities among gelatin structures. This review concisely presents findings and challenges in this research area and suggests needs for more researches on development of rapid authentication method and process-transformed gelatins.

A rapid and simple UPLC-MS/MS method using collagen marker peptides for identification of porcine gelatin

Gelatin, which is mainly derived from bovine and porcine sources, has been used in many foods and pharmaceutical products. To ensure the compliance of food products with halal regulations, reliable analytical methods are very much required. In this study, one unique marker peptide for porcine gelatins was selected to develop an UPLC-MS/MS multiple reaction monitoring method. The capability of this method to identify porcine materials was demonstrated by analyzing in-house-made gelatins containing different amounts of porcine gelatins and commercial gelatin products. The adulteration of porcine gelatin could be sensitively detected at a low level of 0.04%. When combined with HPLC and mass spectrometry, this method is an accurate and sensitive quantitative method to identify porcine gelatins. Thus, the strategy can be used to verify halal authenticity of gelatin.

Gelatin, which is mainly derived from bovine and porcine sources, has been used in many foods and pharmaceutical products.

Gelatin controversies in food, pharmaceuticals, and personal care products: Authentication methods, current status, and future challenges

Gelatin is a highly purified animal protein of pig, cow, and fish origins and is extensively used in food, pharmaceuticals, and personal care products. However, the acceptability of gelatin products greatly depends on the animal sources of the gelatin. Porcine and bovine gelatins have attractive features but limited acceptance because of religious prohibitions and potential zoonotic threats, whereas fish gelatin is welcomed in all religions and cultures. Thus, source authentication is a must for gelatin products but it is greatly challenging due to the breakdown of both protein and DNA biomarkers in processed gelatins. Therefore, several methods have been proposed for gelatin identification, but a comprehensive and systematic document that includes all of the techniques does not exist. This up-to-date review addresses this research gap and presents, in an accessible format, the major gelatin source authentication techniques, which are primarily nucleic acid and protein based. Instead of presenting these methods in paragraph form which needs much attention in reading, the major methods are schematically depicted, and their comparative features are tabulated. Future technologies are forecasted, and challenges are outlined. Overall, this review paper has the merit to serve as a reference guide for the production and application of gelatin in academia and industry and will act as a platform for the development of improved methods for gelatin authentication.

Differentiating collagens based on mitochondrion 12SrRNA gene

Aquatic collagens are one of the main collagens sold in the market due to superior physicochemical and biological activities. In this work, the species of three types of aquatic and commercial collagens were identified by molecular biotechnology. After isolating DNA from bovine, porcine and three types of aquatic animals, DNA was dissolved in a storage buffer. The animals' mitochondrion 12SrRNA sequences were downloaded from the GenBank database, and three pairs of primers that can be used to detect the aquatic collagens were designed by Primer Premier 6 and evaluated by Oligo 7. Analysis of the polymerase chain reaction and agarose electrophoresis showed that the fragments were 440, 307, 112 and 270bp, respectively, thereby enabling successful detection of the collagen species. Results indicate that PCR-based detection methods can also suitably trace the species of aquatic collagens.

Modification of gelatin-DNA interaction for optimised DNA extraction from gelatin and gelatin capsule

BACKGROUND

Poor quality and quantity of DNA extracted from gelatin and gelatin capsules often causes failure in the determination of animal species using PCR. Gelatin, which is mainly derived from porcine and bovine, has been a matter of concern among customers in order to fulfill religious obligation and safety precaution against several transmissible infectious diseases associated with bovine species. Thus, optimised DNA extraction from gelatin is very important for successful real-time PCR detection of gelatin species. In this work, the DNA extraction method was optimised in terms of lysis incubation period and inclusion of pre-treatment pH modification of samples.

RESULTS

The yield of DNA extracted from porcine gelatin was significantly increased when the pH of the samples was adjusted to pH 8.5 prior to DNA precipitation with isopropanol. The optimal pH for DNA precipitation from bovine gelatin solution was then determined at the original pH range of solution: pH 7.6 to 8. A DNA fragment of approximately 300 base pairs was available for PCR amplification.

CONCLUSION

DNA extracted from gelatin and commercially available capsules has been successfully utilised for species detection using real-time PCR assay. However, significant adulterations of porcine and bovine in pure gelatin and capsules have been detected, which require further analytical techniques for validation. © 2015 Society of Chemical Industry.

Enzyme immunoassay for the detection of porcine gelatine in edible bird's nests

Porcine gelatine is a common adulterant found in edible bird's nests (EBNs) used to increase the net weight prior to sale. This study aimed to develop indirect enzyme-linked immunosorbent assays (ELISAs) for porcine gelatine adulteration using anti-peptide polyclonal antibodies. Three indirect ELISAs were developed (PAB1, 2 and 3), which had limits of detection (LODs) of 0.12, 0.10 and 0.11 µg g(-1), respectively. When applied to standard solutions of porcine gelatine, the inter- and intra-assays showed coefficients of variation (CVs) less than 20% and were able to detect at least 0.5 ng µg(-1) (0.05%) porcine gelatine in spiked samples. The proposed ELISA offers attractions for quality control in the EBN industry.

Gelatin quantification by oxygen-18 labeling and liquid chromatography-high-resolution mass spectrometry

Combined with high-performance liquid chromatography (HPLC) and linear-ion trap/Orbitrap high-resolution mass spectrometry, trypsin-catalyzed (16)O-to-(18)O exchange was used to establish an accurate quantitative method for bovine or porcine gelatin. The sophisticated modifications for these two mammalian gelatins were unambiguously identified by accurate mass and tandem mass spectrometry. Eighteen marker peptides were successfully identified for the bovine and porcine gelatin, respectively. The gelatins were subjected to (18)O or (16)O labeling in the presence of trypsin and mixed together in various ratios for quantification. All of the (18)O-labeled peptides were also confirmed by accurate mass and tandem mass spectrometry. The 10 marker peptides with the strongest signals were chosen to calculate the average ratios of (18)O-labeled and (16)O-labeled gelatin. The measured ratios of (18)O-labeled and (16)O-labeled peptides were very close to the mixing ratios of 20:1, 5:1, 1:1, and 1:5 with low standard deviation values. The samples with a mixing ratio of 1:1 (18)O-labeled and (16)O-labeled peptides were determined to 1.00 and 0.99 with standard deviations of 0.02 and 0.04 for bovine and porcine gelatins, respectively, indicating the high accuracy of this method. Trypsin-catalyzed (18)O labeling was proved to be an excellent internal calibrant for gelatins. When combined with HPLC and high-resolution mass spectrometry, it is an accurate and sensitive quantitative method for gelatin in the food industry.

Use of principal component analysis for differentiation of gelatine sources based on polypeptide molecular weights

The study was aimed to differentiate between porcine and bovine gelatines in adulterated samples by utilising sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) combined with principal component analysis (PCA). The distinct polypeptide patterns of 6 porcine type A and 6 bovine type B gelatines at molecular weight ranged from 50 to 220 kDa were studied. Experimental samples of raw gelatine were prepared by adding porcine gelatine in a proportion ranging from 5% to 50% (v/v) to bovine gelatine and vice versa. The method used was able to detect 5% porcine gelatine added to the bovine gelatine. There were no differences in the electrophoretic profiles of the jelly samples when the proteins were extracted with an acetone precipitation method. The simple approach employing SDS-PAGE and PCA reported in this paper may provide a useful tool for food authenticity issues concerning gelatine.

A novel method to differentiate bovine and porcine gelatins in food products: nanoUPLC-ESI-Q-TOF-MS(E) based data independent acquisition technique to detect marker peptides in gelatin

We presented a novel nanoUPLC-MS(E) workflow method that has potential to identify origin of gelatin in some dairy products; yoghurt, cheese and ice cream. In this study, the method was performed in two steps. In the first step, gelatin was extracted from these products before the MS-sample preparation. In the second step, tryptic gelatin peptides were separated and analyzed with ultra-performance liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry (nanoUPLC-ESI-q-TOF-MS(E)). The novelty of this setup was that it functioned in a data independent acquisition mode and that alternate low and elevated collision energy was applied to acquire precursor and product ion information. This enabled accurate mass acquisition on the peptide level to identify the gelatin peptides. The marker peptides specific for porcine and bovine could be successfully detected in the gelatin added to the dairy products analyzed, revealing that the detection of marker peptides in the digested gelatin samples using nanoUPLC-ESI-q-TOF-MS(E) could be an effective method to differentiate porcine and bovine gelatin in the dairy products.