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Cholesterol photosensitized oxidation products in food systems

Cholesterol photosensitized oxidation products in food systems Vladimiro Cardenia, Maria Teresa Rodriguez-Estrada, Giovanni Lercker Department of Agricultural and Food Sciences Alma Mater Studiorum - University of Bologna, Italy. WHY?. enzymic. Chemical. Photosensitized Auto-. OXIDATION.

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Cholesterol photosensitized oxidation products in food systems

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  1. Cholesterol photosensitized oxidation products in food systems Vladimiro Cardenia, Maria Teresa Rodriguez-Estrada, Giovanni Lercker Department of Agricultural and Food Sciences Alma Mater Studiorum - University of Bologna, Italy

  2. WHY? enzymic Chemical Photosensitized Auto- OXIDATION chemical Enzymatic Cholesterol oxidation products (COPs)

  3. More reactive than triplet (32,000 times for monounsaturated structures)

  4. Why to study COPs pro-inflammatory Neurodegenerative diseases pro-apoptotic COPs Diabetes cytotoxic osteoporosis carcinogenic kidney failure mutagenic atherosclerosis * Otaegui-Arrazola A, Menéndez-Carreño M, Ansorena D, Astiasarán I, Menendez-Carreno M. Oxysterols: a world to explore. J Food Chem Toxicol 2010;48:3289–303.

  5. Cholesterol oxidation products (COPs) are usually present in raw food of animal origin (meat, milk, eggs, sea products) Their concentration increases dramatically after exposure to heat, light, metals, natural sensitizers and oxygen, as well as in highly processed food products

  6. Rat hepatocyte HC: hepativ cords IP: inflammatory process *Soto-Rodriguez et al., Journal of Applied Toxicology, 2009, 29, 715-723

  7. Rat aorta E: endothelium layer M: media layer A: adventitia layer L: places where lipids accumulated *Soto-Rodriguez et al., Journal of Applied Toxicology, 2009, 29, 715-723

  8. *Cardenia et al., Biochimie 95, 2013, 473-481

  9. *Cardenia et al., Biochimie 95, 2013, 473-481

  10. BEEF - Sampling

  11. Experimental design

  12. SAMPLE Lipid extraction (Boselli et al., 2001) Cold saponification (Sander et al., 1989) 1/10 9/10 SPE (Rose Sallin et al., 1995) Silylation (Sweeley et al., 1963) Silylation (Sweeley et al., 1963) Total sterols by GC/FID (Boselli et al., 2005) Total COPs by Fast-GC/MS (Cardenia et al., 2012)

  13. Phytosterols 1.3% Total sterolscontent Total sterolcontentranged from 399 to 1343 mg/100 g lipids (283-514 mg/kg of meat)

  14. Total COPs content The total COPs ranged 11.72-39.12 mg/kg of lipids, which corresponded to 0.5–2.1 mg/kg of meat.

  15. Total COPs content The main COPs detected were: 7-HC (1.5-7.5 mg/kg lipids; which corresponded to 0.03-0.52 mg/kg of meat), 7-HC (2.1-9.2 mg/kg lipids, which corresponded to 0.05-1.02 mg/kg of meat), -CE (1.7-9.1 mg/kg lipids, which corresponded to 0.01-0.67 mg/kg of meat), -CE (1.2-5.2 mg/kg lipids, which corresponded to 0.03-0.38 mg/kg of meat), 7-KC (3.2-10.5 mg/kg lipids, which corresponded to 0.06-0.87 mg/kg of meat).

  16. T0 T8D T8L D1 D3 D5 D3 D5 D5 D7 Diets Cholesterol oxidation ratio: T0 T8D T8L 0.1-0.4% 0.2-0.5% 0.2-0.6% Cholesteroloxidation ratio (%) CLA and vE supplied for 90 d led to the lowest cholesterol oxidation ratio, among all dietary treatments. However, no significant effect of light exposure was observed

  17. C n=16 Control group (feed containing maize/soybean without oil addition) OE group (control diet + 3% HOSO + 250 mg/kg α-tocopheryl acetate) O group (control diet + 3% of high-oleic sunflower oil (HOSO) (85% oleic acid and 6.9% linoleic acid)) OE n=16 O n=16 n=64 E n=16 E group (control diet supplemented with 250 mg/kg α-tocopheryl acetate) PORK - Sampling

  18. Experimental design T3L

  19. Diets Storage a 18.0 16.0 14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0 14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0 mg/kg lipids mg/kg lipids C O E OE T0 T3D T3L No significant effect of the storage conditions on the total COP content was found Total COP content of the pork slices ranged from 8.5 to 16.4 mg/kg of lipids ( 0.5-1.1 mg/kg meat) Meat obtained with diet E and kept at dark had a significantly lower total COP content * Total COPs content

  20. 0.3 0.2 0.1 0.0 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 T3D T0 T3L T0 T3D T3L 7-KC -CE -CE 7-HC 7-HC C O E OE mg/kg meat C O E OE C O E OE C O E OE 7-Ox CE 7-Ox CE 7-Ox CE • Cholesterol oxidation ratio= 0.1-0.25%. • 7-KC was significantly higher in samples without supplementation of VE. • Antioxidant efficacy of vitamin E toward an actual rise of the main single COP during storage at dark, was also confirmed. Cholesteroloxidation ratio Oxidation ratio (%)

  21. Experimental design FRESH SARDINES T0 T = -80°C CLEANED SARDINES LIGHT T = 4°C DARK T = 4°C 4 h 4 h 2 h 1 h 1 h 2 h T4 L T4 D T1 L T1 D T2 L T2 D

  22. 7-KC 24% 5,6β-EC 22% 5,6α-EC 12% 7β-HC 20% Triol 9% 7α-HC 13% Total COPs= 0.6 – 3.72 µg/g muscle >> threshold of toxicological concern (TTC) for unclassified compounds (0.15 g per person per day) (Kroes et al., 2004)

  23. COPs at T0 vs T4 * ** STORAGE EFFECT

  24. Cholesterol oxidation ratio

  25. Cholesterol oxidation ratio a b c

  26. Conclusions • Cholesterol photosensitized oxidation is one of the main chemical degradations that occurs in food systems, leading to the formation of compounds that are related to aging, various chronic and degenerative diseases. • The extent of such degradation will depend on the presence of antioxidants/pro-oxidants, the unsaturation degree of fatty acids, and environmental conditions.

  27. Conclusions • COPsformation can be contrasted by : • addingantioxidantsthroughfeeding (suchasvitamin E) or surfacesprayingbefore packaging (i.e. water- solubleantioxidants); • usinglow processing temperature; • proper packaging (with lowoxygenpermeability, suitable light filters, colored/reflectingfilms, and protectiveatmosphere/vacuum); • appropriate lightingconditions(source, color, energy, distance).

  28. Conclusions • The combined use of some of these strategies during commercial retail storage, can efficiently prevent cholesterol photo-oxidation without modifying the food product composition and sensory properties. • Although the cholesterol oxidation rate does not usually exceed 0.9% of cholesterol in food, further research is required on the actual toxicity levels of single and mixed COPs, to better ascertain if the COPs content in photo-oxidized food represents a risk for human health.

  29. Dr. Maria Teresa Rodriguez Estrada Prof. Giovanni Lercker Department of Agricultural and Food Sciences Alma Mater Studiorum University of Bologna E-mail: vladimiro.cardenia3@unibo.it

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