Pangan Fungsional_Senyawa Karotenoid dan Likopen.pptx

Membahas definisi, struktur, klasifikasi,reaksi serta peran karotenoid dan likopen sebagai senyawa bioaktif dalam pangan fungsional.

1. Pangan Fungsional Karotenoid dan Likopen

2. Mekanisme yang Memicu Autooksidasi dalam Sistem Pangan Autooksidasi adalah rantai reaksi yg mendegradasi hidrokarbon contohnya polimer , lipid, protein, dan DNA dalam makhluk hidup Dipicu pembentukan radikal peroksil krn adanya reaksi dg oksigen dalam molekul organik atau atmosfer Kerusakan lipid: selama prosesing , handling, dan penyimpanan Oksidasi lipid unsaturated dikatalisis panas , cahaya , radiasi , logam , metallo -protein, lipoksigenase

3. Mekanisme yang Memicu Autooksidasi dalam Sistem Biologis Disebabkan oleh pembentukan senyawa radikal bebas yg sangat reaktif dg oksigen molekular  radikal peroksil dan hidroperoksida yg menginisiasi reaksi berantai Prooksidan menyerang PUFA, fosfolipid , kolesterol bebas , DNA, dan protein  health implication

4. Oksidasi lipid Terdiri dari 3 tahap : Inisiasi  pembentukan radikal bebas Propagasi  reaksi berantai radikal bebas Terminasi  pembentukan senyawa nonradikal

5. Inisiasi Ketika kontak dg oksigen , sebuah senyawa lipid tak jenuh berubah menjadi radikal  kehilangan radikal dari gugus allylic methylene Pembentukan radikal lipid biasanya dipicu oleh adanya trace metal, iradiasi , cahaya , panas

6. Reactive Oxygen Species (ROS)

7. Propagasi Radikal bebas diubah menjadi radikal lain  reaksi berantai Initial formation becomes responsible

8. Terminasi Oksidasi lipid mengalami terminasi ketika 2 radikal berinteraksi

9. Mekanisme Oksidasi Lipid pada Sistem Biologis Oksidasi lipid  proses biologis yg normal terjadi ketika tubuh butuh energi Oksidasi lipid yg tdk terkontrol  penyebab penyakit spt : atherosklerosis , kanker , degenerasi saraf Asam lemak hidroperoksida : produk utama dari oksidasi PUFA Peningkatan kadar LOOH saat cellular injury  disruption of biological membranes, inaktovasi enzim , perusakan protein dan molekul DNA.

10. Sumber radikal bebas : endogenous Normal aerobic respiration – As a result of normal aerobic respiration, mitochondria consume molecular oxygen, reducing it by sequential steps to produce water. The formation of O2•-, H2O2, and •OH occurs by successive additions of electrons to O2• Cytochrome oxidase adds four electrons fairly efficiently during energy generation in mitochondria, but some of the toxic intermediates are inevitable by-products. In a study conducted on rats, about 10 12 oxygen molecules are processed by each rat cell daily, and the leakage of partially reduced oxygen molecules is about 2%, yielding about 2x1010 superoxide and hydrogen peroxide molecules per cell per day (Ames et al., 1993) Peroxisomes, which are organelles responsible for degrading fatty acids and other molecules, produce H2O2 as a by-product, which is then degraded by catalase. Under certain conditions, some of the peroxide escapes degradation, resulting in its release into other compartments of the cell and in increased oxidative DNA damage.

11. Sumber radikal bebas : endogenous Cytochrome P-450 enzymes in animals constitute one of the primary defense systems against natural toxic chemicals from plants, the major source of dietary toxins. The induction of these enzymes, prevent acute toxic effects from foreign chemicals, but also results in oxidant by-products that damage DNA. Phagocytic cells destroy bacteria or virus-infected cells with an oxidative burst of NO, O2•-, H2O2, and OCl -. Chronic infection by viruses, bacteria, or parasites, results in a chronic phagocytic activity and consequent chronic inflammation, which is a major risk factor for cancer. Chronic infections are particularly prevalent in third world countries.

12. Sumber radikal bebas : exogenous Cigarette smoking: The oxides of nitrogen ( NOx ) in cigarette smoke (about 1000 ppm) cause oxidation of macromolecules, and deplete antioxidant levels. This is likely to contribute significantly to the pathology of smoking. Smoking is a risk factor for heart disease as well as a wide variety of cancers in addition to lung cancer. Dietary factors: Iron and copper salts promote the generation of oxidizing radicals from peroxides. Men who absorb significantly more than normal amounts of dietary iron due to a genetic defect (hemochromatosis disease) are at an increased risk for both cancer and heart disease. It has, therefore, been argued that too much dietary copper or iron, particularly heme iron (which is high in meat), is a risk factor for cardiovascular disease and cancer in normal men.

13. Sumber radikal bebas : exogenous Normal diets contain plant food with large amounts of natural phenolic compounds, such as chlorogenic and caffeic acid, that may generate oxidants by redox cycling. Radiation/UV light: UVA rays constitute 90-95% of the ultraviolet light reaching the earth. They have a relatively long wavelength (320-400 nm) and are not absorbed by the ozone layer. UVA light penetrates the furthest into the skin and is involved in the initial stages of sun tanning. UVB rays are partially absorbed by the ozone layer and have a medium wavelength (290-320 nm). They do not penetrate the skin as far as the UVA rays do and are the primary cause of sunburn. They are also responsible for most of the tissue damage which results in wrinkles and aging of the skin and are implicated in cataract formation. UVC rays have the shortest wavelength (below 290 nm) and are almost totally absorbed by the ozone layer. As the ozone layer thins UVC rays may begin to contribute to sunburning and premature aging of the skin. All forms of ultraviolet radiation are believed to contribute to the development of skin cancer.

14. Sumber radikal bebas : exogenous Strenuous work or exercise: During exercise the increase in whole body oxygen consumption of 10-20 fold causes a severe disturbance of various biochemical pathways. The oxygen flux in individual muscle fibers is believed to increase by as much as 100-200 fold. This tremendous increase in oxygen consumption results in an increased leakage of electrons from the mitochondrial respiratory chain, forming various one-electron oxygen intermediates, such as superoxide anion, hydrogen peroxide and hydroxyl radicals. These reactive oxygen species (ROS) are capable of triggering a chain of damaging reactions in the cell, such as lipid peroxidation, inactivation of certain enzymes, alteration of cellular oxidoreductive status, and oxidative damage to proteins and DNA.

15. Klasifikasi Antioksidan berdasarkan Fungsinya Primer / antioksidan pemutus rantai (scavenging antioxidants)  dapat menetralkan radikal bebas dg mendonorkan elektronnya . Sekunder / antioksidan preventif , mekanisme : Mengikat ion logam transisi yg tdk ikut berpartisipasi dalam reaksi katalisis dg logam Menghilangkan peroksida dg katalase dan glutathione peroksidase yg bereaksi dg ion logam transisi membentuk ROS Penghilangan ROS Oxygen scavanger : asam askorbat , askorbil palmitat , sulfit , erythorbat Chelators : etilendiamintetraasetik (EDTA), asam sitrat , fosfat ( bukan antioksidan , tetapi memiliki aktivitas sinergis dari antioksidan primer dan oxygen scavanger )

16. Tersier : menghilangkan biomolekul yg rusak sebelum terakumulasi

17. KAROTENOID Studi epidemiologis menyatakan bhw konsumsi buah dan sayur dpt mencegah berbagai penyakit terutama kanker Salah satu senyawa aktif pd sayur dan buah  karotenoid Karotenoid tdk dpt disintesis oleh mamalia termasuk mns  sumber dari makanan Karotenoid ditemukan pd bahan makanan dlm bentuk all-trans poliena C40 yg disusun dari 8 buah isoprena dg 5 atom C Linear: likopen , cincin pd salah satu ujung ( γ karoten , citranaxanthin ), cincin pd kedua ujung ( β - karoten , β - kriptosantin , lutein)

18. Karotenoid utama dlm bahan makanan

19. Karotenoid utama dlm bahan makanan

20. Struktur umum karotenoid

21. Struktur umum karotenoid Ikatan ganda terkonjugasi dari molekul karotenoid , mudah mengalami degradasi oksidatif Karotenoid dlm bahan [ angan relatif stabil , tetapi ketika struktur rusak dan terekspos panas , cahaya , oksigen , peroksida , logam , enzim lipoksigenase  terdegradasi dg cepat  mengarah ke bleaching (color loss) dan biological function loss

22. Penyerapan karotenoid dalam tubuh Karotenoid  hidrofobik , tdk larut dalam lingkungan larutan salura pencernaan Perlu dilarutkan dalam lipid dan lipid + bile salt untuk selanjutnya diserap di enterosit dalam brush border Absorbsi perlu didampingi dietary lipid dan enzim terutama lipase. Lipase menghasilkan FFA yg membentuk kompleks dlm misel (bile salts, lecithin, AG, FFA, dan komponen lipofilik minor)

23. Penyerapan karotenoid dalam tubuh

24. Reaksi antioksidan karotenoid Singlet energy transfer: Carotenoids in the chloroplast act as antenna pigments by their ability to become singlet excited by a much broader spectrum of light than chlorophyll. The excited carotenoid can then pass on the energy to produce singlet excited chlorophyll which can then undertake to process of photosynthesis.

25. Reaksi antioksidan karotenoid Triplet energy transfer: Under some conditions molecules can absorb light to produce triplet excited states. The carotenoids, because of their polyene structure, are able to absorb the excitation energy to become triplet excited and then decay exothermically to their ground state, thus preventing the production of potentially damaging radicals.

26. Reaksi antioksidan karotenoid Singlet [O] quenching: Light or chemical action can convert ground-state oxygen ('0,) to singlet oxygen ( 1 2 )which is extremely reactive. Singlet oxygen can be quenched by reacting with the carotenoid to produce triplet-excited carotenoid which decays exothermically as before.

27. Reaksi antioksidan karotenoid Reaction with radical species : The conjugated polyene backbone of the carotenoids has the ability to delocalize a charge or an unpaired electron  donation of a hydrogen molecule These physical chemical properties confer the ability to act as an antioxidant and to terminate free radical reactions in vitro with the production of resonance-stabilized free radical structures