Presentation on theme: "BIOCHEMISTRY OF FOOD SPOILAGE"— Presentation transcript:
1BIOCHEMISTRY OF FOOD SPOILAGE Charul1, Jayanti Tokas2, Shalini Jain3 and Hariom Yadav41Department of Biochemistry, CCS HAU, Hisar, Haryana, India2National Agri-Food Biotechnology Institute, Mohali, Punjab, IndiaPPT original -
2Human Growth Food Proteins Carbohydrate Vitamins Lipids Energy Building materialsHuman Growth
3Highly Perishable Semi perishable Stable FOOD GROUPS Meat Fruit Milk VegetablesEggsSemi perishablePotatoesNutsFlourStableRiceDry beans
12Effect of chlorophyll on pentenyl furan peak areas Light Exposure(d) Added Chlorophyll0 ppm1 ppm5 ppm1231502415343018(Callison, 2001)
13Riboflavin Photosensitized Singlet Oxygen Oxidation of Vitamin D vitamin D-5,6 epoxide(King, 1996)
14Head space oxygen of vitamin D2 samples with 15 ppm riboflavin stored in the dark from 1-8 hours (King and Min, 1998)
15Effect of vitamin D2 and riboflavin concentrations on % headspace oxygen loss during storage in the light from 1 to 8 hours(King and Min, 1998)
16Singlet Oxygen and Ascorbic Acid Effects on Dimethyl Disulfide and Off-Flavor in Skim Milk Exposed to LightMethionineDimethyl DisulfidePostulated mechanism of dimethyl disulfide formation by singlet oxygen oxidation of methionine.(Jung et al., 1998)
17Effects of time of exposure to fluorescent light on headspace volatile compounds and dimethyl disulfide of skim milkA - 2-butanoneB - ethanolC - diacetylD - dimethyl disulfideE - n-butanol(Jung et al., 1998)
18Dimethyl Disulphide (peak D) Effects of ascorbic acid concentration on dimethyl disulfide (peak D) content in skim milk during light exposure for 1h.Ascorbic acid (ppm)Dimethyl Disulphide (peak D)132692006158500490710004742(Jung et al., 1998 )
19Greening of potato Biosynthesis of chlorophyll LightBiosynthesis of chlorophyllFixation of carbon dioxideAcetateMevolenic acidCholesterol
21Chlorophyll and solanine synthesis in potatoes Light23⁰CDark(Ramaswamay et al., 1976)
22Enzymes Food Spoilage action Enzymes that cause food spoilageEnzymesFoodSpoilage actionAscorbic acid oxidaseVegetablesDestruction of vitamin CLipaseMilk, oilsHydrolytic rancidityLipoxygenaseDestruction of vitamin APectic enzymesFruitsDestruction of pectic substances (Softening)PeroxidasesBrowningPolyphenoloxidaseFruits, vegetablesBrowning, off flavour, vitamin lossProteasesEggscrab, lobsterFlourReduction of shelf lifeOvertenderizationReduction in gluten network formationThiaminaseMeats, fishDestruction of thiamine
23ENZYMATIC BROWNING Hydroxylation of monophenol to o-diphenol Polyphenol oxidaseHydroxylation of monophenol to o-diphenolPhenolicsubstrateO2O2Polyphenol oxidasePhenolicsubstrateO2O2O2O2O2Dehydrogenation of o- diphenol to o-quinone
24Oxidation of tyrosine by Phenolase and the formation of melanin pigment
25Post-mortem changes in fish muscle due to autolytic degradation Autolysis(Green, 2011)
26An overview of fruit ripening with particular emphasis on textural softening Protopectin → Soluble Pectin → SofteningDecomposition (over matured fruit)
31Microbial SpoilageFoods and microorganisms have long and interesting associations which developed long before the beginning of recorded history. Foods are not only nutritious to consumers, but are also excellent source of nutrients for microbial growth. Depending upon the microorganisms present, foods may spoil or preserved by fermentation.Microorganisms can be used to transform raw foods into fermented delights, including yoghurt, cheese, sausages, tempeh, pickles, wine, beers and other alcoholic products. On the other hand, foods also can act as a reservoir for disease transmission, and thus detection and control of pathogens and spoilage organisms are important areas of food microbiology. During the entire sequence of food handling from the producer to the final consumer, microorganisms can affect food quality and human health.
49Pectin Degradation Polygalacturonic acid + Methanol Pectin Apple rot Penicillium expansum Soft and wateryDry and firmMonilinia fructigena
50Slime productionEPSSchematic representation of the EPS biosynthetic pathway in L. lactis leading to the synthesis of B40-EPS. Glycolysis is depicted on the left and leadsto the production of pyruvate, which is then converted into lactate by lactate dehydrogenase (LDH). The glycolytic intermediate glucose-6-phosphate(glucose-6P) is converted to glucose-1-phosphate (glucose-1P) by the action of phosphoglucomutase (PGM). Glucose-1-phosphate is the centralintermediate in the conversions leading to the B40-EPS precursors UDP-glucose, UDP-galactose and dTDP-rhamnose. The final step of EPSbiosynthesis involves a multienzyme pathway encoded by the eps genes (EPS machinery). GalU, UDP-glucose pyrophosphorylase; GalE, UDPgalactoseepimerase; Rfb, glucose-1-phosphate thymidylyltransferase, TDP-glucose oxidoreductase, dTDP-4-dehydrorhamnose 3,5-epimerase,dTDP-4-keto-L-rhamnose reductase.
51Viscosity of medium during growth of Pediococcus damnosus 2 Viscosity of medium during growth of Pediococcus damnosus 2.6 (◊) and Lactobacillus brevis G-77 (□) at 28°C for 24 h.(Martenssona et al., 2003)
52Ropiness of medium during growth of Pediococcus damnosus 2 Ropiness of medium during growth of Pediococcus damnosus 2.6 (◊) and Lactobacillus brevis G-77 (□) at 28°C for 24 h(Martenssona et al., 2003)
53Rope-Producing Strains of Bacillus spp. from Wheat Bread Total numbers of rope-spoiled breads during storage at 23 and 30°C(Pepe, et. al., 2003)
54Summary of bacterial pathways leading to spoilage aroma and flavor compounds of wine
553-Methylthiopropionaldehyde as Precursor of Dimethyl Trisulfide in Aged Beers (Gijs et al., 2000)
58Prevention By keeping out microorganisms By hindering the growth and activity of microorganismsLow temperatureDryingChemicalsAntibioticsBy killing the microorganisms
59ConclusionFoods spoil due to physical, chemical and microbial degradation with their metabolites being the cause of the off-flavours or the textural changes resulting in sensory rejection.These factors are interrelated, as certain temperatures and oxygen and moisture levels increase the activities of endogenous enzymes and of microbes.Rodent and insect damage may provide an entry point for microbial growth.Which microorganisms will develop or what (bio)chemical reactions occur is dependant upon food derived or environmental factors.
60ConclusionAlthough food spoilage is a major economical loss, the underlying integrated mechanisms are still poorly understood.There is a need for the identification and control of growth of Specific spoilage organism (SSO) present on different food commodities. As yet not many SSO have been identified.Therefore, the estimation of the quality of a food product still relies on the quantification of total numbers of microorganisms, which in some cases is a very poor reflection of the actual quality.In addition to the identification of SSO, a better understanding of the complex interaction between SSO and other microorganisms or their metabolites is needed.Finally the interaction between microbial spoilage and chemical spoilage has to be elucidated.