Supplementary data for the article: Cirkovic Velickovic, T. D.; Stanic-Vucinic, D. J. The Role of Dietary Phenolic Compounds in Protein Digestion and Processing Technologies to Improve Their Antinutritive Properties. Comprehensive Reviews in Food Science and Food Safety 2018, 17 (1), 82–103. https://doi.org/10.1111/1541-4337.12320

Supplementary material for: [https://doi.org/10.1111/1541-4337.12320]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2074

Supplementary data for the article: Cirkovic Velickovic, T. D.; Stanic-Vucinic, D. J. The Role of Dietary Phenolic Compounds in Protein Digestion and Processing Technologies to Improve Their Antinutritive Properties. Comprehensive Reviews in Food Science and Food Safety 2018, 17 (1), 82–103. https://doi.org/10.1111/1541-4337.12320

Supplementary material for: [https://doi.org/10.1111/1541-4337.12320]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2074

Supplementary data for article: Stanić-Vučinić, D.; Prodić, I.; Apostolović, D.; Nikolić, M.; Ćirković-Veličković, T. Structure and Antioxidant Activity of Beta-Lactoglobulin-Glycoconjugates Obtained by High-Intensity-Ultrasound-Induced Maillard Reaction in Aqueous Model Systems under Neutral Conditions. Food Chemistry 2013, 138 (1), 590–599. https://doi.org/10.1016/j.foodchem.2012.10.087

Supplementary material for: [https://doi.org/10.1016/j.foodchem.2012.10.087]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1583

Investigation of structural changes in ovalbumin induced by two types of MPs and its impact on protein digestibility

Ovalbumin (OVA) is the most abundant protein in chicken egg white. It is one of the major allergens in eggs. Micro- and nanoplatic particles (MNPs) are a widespread contaminant and have been found in food and water. It is still unclear how MNPs might affect human health. However, due to their large surface area they have been found to bind various biopolymers, including proteins. These biopolymers can be bound more strongly or loosely, and are referred to as hard and soft corona, respectfully [1]. MPs have been found in eggs, in the size range of 50-100 μm [2]. It is shown that these particles can interact with proteins and induce structural changes, but there is still not enough information on this topic [3]. These structural changes could lead to a decreased digestibility in the gastrointestinal tract, which could increase the immune response to known allergens. The aim of this study was to determine whether there are structural changes present in the OVA after incubation with two types of MPs – 120 μm polyethylene terephthalate (PET) and 120 μm polystyrene (PS) and whether they could influence digestion of OVA with gastrointestinal enzymes. 20 mg of MPs were incubated with 1.3 mg/mL ovalbumin for 4 h at room temperature in a 20 mM phosphate buffer at pH 7. Bulk ovalbumin was separated from the MPs by centrifugation and by filtration through a 0.22 μm PVDF filter. Soft corona was obtained by washing the MPs with water, and the MPs were later removed as described with bulk ovalbumin. Formation of amyloids was monitored with a Thioflavin T (ThT) assay at room temperature and after thermal treatment, and additional structural analysis was performed by circular dichroism (CD) spectrometry in the far-UV region. Thermal stability was also determined by spectrofluorimetry. Digestion with two proteases (pepsin and trypsin) was performed to determine whether there is a change in the gastrointestinal digestibility of OVA. Results from the ThT assay show that at room temperature there is no significant difference between the fluorescence emission obtained for all samples, with bulk OVA from both MPs showing a slight decrease. However, there is an increase of fluorescence after thermal treatment in all OVA samples, where OVA from the soft corona emits significantly less fluorescence than control and bulk samples for both types of MPs. Additionally, soft coronas have been shown to have more β-sheet content than other samples, which is more pronounced for OVA incubated with PET. For the heated samples there is a sharp change from α-helix to β-sheets in all the samples, but it is the most dramatic in the soft coronas. This could impose rigidity to the tertiary structure, which would explain why the ThT molecule does not bind as strongly. Despite differences in both the secondary and tertiary structure, the thermal stability is almost the same in all samples. Digestion of the samples shows that the soft corona incubated with PS tends to be more resistant to trypsin than other samples after 2 min, but it is not significant. For digestion with pepsin there is no difference between the samples. In conjunction with the previous results, which indicates a structural stabilisation of the soft corona at pH 7, it is not surprising that there is an increased resistance to trypsin, compared to pepsin which is a gastric enzyme and for which digestion is performed at an acidic pH. In conclusion, there is a structural change present in samples upon contact with MPs, particularly in the soft corona, of which the most pronounced is a decrease of α-helix content and increase in β-sheet content as determined by far-UV CD. This leads to a structural stabilization which could further impact the digestibility of the OVA protein and impact its allergenicity. However, this must be confirmed with further experiments. Acknowledgments: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 965173. References: [1] M.P. Monopoli, C. Åberg, A. Salvati, K.A.Dawson, Nat. Nanotechnol., 7 (2012) 779-786. [2] Q. Liu, Z. Chen, Y. Chen, F. Yang, W. Yao, Y. Xie. Food Chem., 397 (2022) 133771. [3] P. Ju, Y. Zhang. Y. Zheng, F. Gao, F. Jiang, J. Li, C. Sun, Sci. Total Environ., 734 (2020) 139219

Investigation of structural changes in ovalbumin induced by two types of MPs and its impact on protein digestibility

Ovalbumin (OVA) is the most abundant protein in chicken egg white. It is one of the major allergens in eggs. Micro- and nanoplatic particles (MNPs) are a widespread contaminant and have been found in food and water. It is still unclear how MNPs might affect human health. However, due to their large surface area they have been found to bind various biopolymers, including proteins. These biopolymers can be bound more strongly or loosely, and are referred to as hard and soft corona, respectfully [1]. MPs have been found in eggs, in the size range of 50-100 μm [2]. It is shown that these particles can interact with proteins and induce structural changes, but there is still not enough information on this topic [3]. These structural changes could lead to a decreased digestibility in the gastrointestinal tract, which could increase the immune response to known allergens. The aim of this study was to determine whether there are structural changes present in the OVA after incubation with two types of MPs – 120 μm polyethylene terephthalate (PET) and 120 μm polystyrene (PS) and whether they could influence digestion of OVA with gastrointestinal enzymes. 20 mg of MPs were incubated with 1.3 mg/mL ovalbumin for 4 h at room temperature in a 20 mM phosphate buffer at pH 7. Bulk ovalbumin was separated from the MPs by centrifugation and by filtration through a 0.22 μm PVDF filter. Soft corona was obtained by washing the MPs with water, and the MPs were later removed as described with bulk ovalbumin. Formation of amyloids was monitored with a Thioflavin T (ThT) assay at room temperature and after thermal treatment, and additional structural analysis was performed by circular dichroism (CD) spectrometry in the far-UV region. Thermal stability was also determined by spectrofluorimetry. Digestion with two proteases (pepsin and trypsin) was performed to determine whether there is a change in the gastrointestinal digestibility of OVA. Results from the ThT assay show that at room temperature there is no significant difference between the fluorescence emission obtained for all samples, with bulk OVA from both MPs showing a slight decrease. However, there is an increase of fluorescence after thermal treatment in all OVA samples, where OVA from the soft corona emits significantly less fluorescence than control and bulk samples for both types of MPs. Additionally, soft coronas have been shown to have more β-sheet content than other samples, which is more pronounced for OVA incubated with PET. For the heated samples there is a sharp change from α-helix to β-sheets in all the samples, but it is the most dramatic in the soft coronas. This could impose rigidity to the tertiary structure, which would explain why the ThT molecule does not bind as strongly. Despite differences in both the secondary and tertiary structure, the thermal stability is almost the same in all samples. Digestion of the samples shows that the soft corona incubated with PS tends to be more resistant to trypsin than other samples after 2 min, but it is not significant. For digestion with pepsin there is no difference between the samples. In conjunction with the previous results, which indicates a structural stabilisation of the soft corona at pH 7, it is not surprising that there is an increased resistance to trypsin, compared to pepsin which is a gastric enzyme and for which digestion is performed at an acidic pH. In conclusion, there is a structural change present in samples upon contact with MPs, particularly in the soft corona, of which the most pronounced is a decrease of α-helix content and increase in β-sheet content as determined by far-UV CD. This leads to a structural stabilization which could further impact the digestibility of the OVA protein and impact its allergenicity. However, this must be confirmed with further experiments

Supplementary material for the article: Radibratovic, M.; Minic, S.; Stanic-Vucinic, D.; Nikolic, M.; Milcic, M.; Velickovic, T. C. Stabilization of Human Serum Albumin by the Binding of Phycocyanobilin, a Bioactive Chromophore of Blue-Green Alga Spirulina: Molecular Dynamics and Experimental Study. PLoS ONE 2016, 11 (12). https://doi.org/10.1371/journal.pone.0167973

Supplementary material for: [https://doi.org/10.1371/journal.pone.0167973]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1948

Evaluacija kriterijuma za dijagnozu atopijskog dermatitisa i detekcija alergen specifičnih IgE antitela kod pasa alergičnih na polen biljke Ambrosia artemisiifolia

Common ragweed (Ambrosia atremisiifolia) is one of the most frequent causes of pollen-induced allergic reactions both in humans and dogs. It has not been defined yet, what is the major allergen(s) to which most dogs allergic to ragweed show a positive result on intradermal skin test (IDST). In the present study sensitization to Ambrosia artemisiifolia pollen allergens in dogs with atopic dermatitis was examined with both in vivo and in vitro tests, including IDST and serum allergen specific IgE test. Detection of specific-IgE antibodies against ragweed allergens by immunoblotting in the sera of allergic dogs was optimized, as well. Dogs that were positive, as judged by IDST reactions to ragweed pollen allergens, also had alergen specific IgE antibodies in their sera. Results indicate that major allergens of A. artemisifolia pollen in dogs are Amb a 1 and Amb a 2. Further characterization of ragweed allergens is needed before they could potentially be used in intradermal testing or allergen immunotherapy in affected dogs. Also, we evaluated new Favrots diagnostic criteria for canine atopic dermatitis in dogs allergic to Ambrosia atremisiifolia pollen. It might be concluded that proposed criteria are of great assistance for seting up suspected diagnosis of canine atopic dermatitis, after ruling out other pruritic dermatoses.Kratka ambrozija (Ambrosia artemisiifolia) je jedan od najčešćih uzročnika alergijskih reakcija izazvanih polenom kod ljudi i pasa. Još uvek nije definisano koji je glavni alergen (i), na koji, većina pasa alergičnih na polen ambrozije, ispoljava pozitivnu reakciju na intradermalnom testu. U ovoj studiji je ispitana senzibilizacija na polen ove biljke kod pasa sa simptomima atopijskog dermatitisa in vivo i in vitro testovima, uključujući intradermalni test i dokazivanje prisustva alergen specifičnih IgE antitela u serumu. Optimizovani su uslovi za detekciju IgE specifičnih antitela iz seruma pasa alergičnih na polen ambrozije imunoblot tehnikom. Psi koji su imali pozitivnu reakciju na polen ove biljke na intradermalnom testu, takođe su imali specifična IgE antitela u serumu. Dobijeni rezultati ukazuju da su glavni alergeni Ambrosia artemisiifolia kod pasa Amb a 1 i Amb a 2. Neophodna je dalja karakterizacija alergena ambrozije kako bi se oni mogli primeniti pri rutinskom intradermalnom testiranju ili u alergen specifičnoj imunoterapiji obolelih pasa. Takođe je razmatrana i validnost Favrotovih dijagnostičkih kriterijuma kod pasa alergičnih na polen ambrozije. Može se zaključiti da su predloženi kriterijumi od velike pomoći u postavljanju suspektne dijagnoze atopijskog dermatitisa pasa, nakon isključenja drugih pruritičnih dermatoza

Extraction and quantification of tropomyosin in selected samples of shellfish

Food allergies affect up to 10% of the general population and represent an important health problem in the field of food safety in industrialized countries. Hence, developing reliable, specific, and sensitive methods for detecting and quantifying allergens in food products is of high importance. Shellfish have been recognized as one of the eight most common sources of allergens, with tropomyosin (TPM) being considered a major heat-stable allergen, having a highly conserved amino acid sequence among different shellfish species. Allergenicity of TPM may change during food processing, such as cooking. The objective of this study was to develop an enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of shellfish tropomyosin in food samples. Two different extraction buffers - phosphate-buffered saline (PBS) and PBS containing 1 M sodium-chloride (PBSN), were compared for their ability to recover proteins from pre-cooked frozen Mediterranean mussel (Mytilus galloprovincialis) and fresh frozen razor mud shrimp (Solenocera melantho). The samples were additionally cooked according to the manufacturer's instruction and analyzed as such. The protein content was quantified using Bradford protein assay, and the protein components of soluble extracts were profiled using SDS-PAGE. TPM presence was confirmed using Western blot. Sandwich ELISA was developed using a monoclonal anti-TPM antibody as a capture antibody, while polyclonal anti-TPM antibody served as a detection antibody and was coupled to the biotinylated secondary antibody and streptavidin-alkaline phosphatase conjugate. Tropomyosin was quantified using highly purified natural shrimp tropomyosin as standard. The profile of extracted proteins was changed when using PBSN instead of PBS. A higher concentration of proteins was recovered from raw shrimp using PBSN instead of PBS. At the same time, the type of extraction buffer did not affect protein recovery either from heated shrimp or pre-cooked/heated mussels. Significantly fewer proteins were extracted from cooked shrimp sample compared to the raw shrimp, while cooking showed no effect on the extraction of proteins from mussels. Cooking did not affect TPM recognition in Western blot. TPM was quantified in shrimp samples in sandwich ELISA. However, developed ELISA could not quantify mussel's TPM, indicating that this approach may distinguish mussels and shrimp TPM

Ultrasensitive Quantification of Crustacean Tropomyosin by Immuno-PCR

Tropomyosin is the major and predominant allergen among shellfish. This study developed an ultrasensitive immuno-PCR method for the quantification of crustacean tropomyosin in foods. The method couples sandwich ELISA with the real-time PCR (rtPCR) amplification of marker DNAs. Monoclonal anti-TPM antibody was the capture antibody, polyclonal rabbit anti-shrimp tropomyosin antibody was the detection antibody, while natural shrimp tropomyosin served as the standard. A double-stranded amino-DNA was covalently conjugated to a secondary anti-rabbit antibody and subsequently amplified and quantified via rtPCR. The quantification sensitivity of immuno-PCR was 20-fold higher than analogous ELISA, with LOQ 19.8 pg/mL. The developed immuno-PCR method is highly specific for the detection of crustacean tropomyosin and is highly precise in a broad concentration range. Tropomyosin recovery in the spiked vegetable soup was 87.7–115.6%. Crustacean tropomyosin was also quantified in commercial food products. The reported immuno- PCR assay is the most sensitive method for the quantification of crustacean tropomyosin and is the first immuno-PCR-based assay for the quantification of food allergen and food protein in general. The described method could be easily adapted for the specific and ultrasensitive immuno-PCR-based detection of traces of any food allergen that is currently being quantified with ELISA, which is of critical importance for people with food allergies