ALBERT

Description: Fish sauce is a popular fermented product used in south Asian countries which is made from different small fishes in this research work it was attempted to produce fish sauce from kilka of the Caspian sea, the fish sauce was made from three models of kilka ,such as whole kilka , cooked whole kilka and dressed kilka , each of these models treated it four different fashions of fermentation such as:1- Traditional method, 2- Enzymatic method 3- Microbial method, 4- Mixture of enzyme and microb The results of this investigation showed that time of fermentation for the traditional method was six month, enzymatic method one month, microbial method 3 month and the mixture of enzyme and microb 1 month. The rate of fermentation was least for dressed Kilka, microbial and biochemical changes of Kilka fish sauce were evaluated, total bacterial count was 2.1-6.15 log cfu/ml total volatile nitrogen (TVN) in samples recorded was 250 mg /100g, the amount of protein varied between 10-13 percent, the name of commercial enzymes added was Protamex and Flavourzyme, the bacteria added was L act ob acillus and Pediococous, fish sauce containers fish and 20% salt, temperature of keeping for fermentation was 37 degree c for 6 month.

Description: PhD

Description: Advisors: S. Moini Counsellors: A. keyvan, Gh. Vosoughi

Description: The first aim of this research was to identify fatty acids, amino acids composition of Thunnustonggol roe and their changes during cold storage (-18'C). The second aim was to determinethe changes of moisture, protein, fat and ash contents of the roe during one year cold storage(-18'C). 60 samples of longtail tuna (Thunnus tonggol) ovaries were randomly collected formBandar-e-Abbas landings. The samples were frozen at-30'C and kept in cold store at -18'Cfor one year. According to a time table, the samples were examined for identification offatty acids, amino acids, moisture, protein, fat, ash, peroxide and T.V.N. and their changeswere evaluated during this time. The results showed that 26 fatty acids were identified. Theunsaturated fatty acids (UFA) and saturated fatty acids (SFA) were 62.33 and 37.6%,respectively, in fresh roe. So that, DHA (C22:6) and oleic acid (C18:1) had high amounts(24.79 and 21.88%) among the UFA and palmitic acid (C16:0) was the most content(22.75%) among the SFA. The PUFA/SFA was 0.91. Also, 17 amino acids were identifiedthat essential amino acids (EAA) and nonessential amino acids (NE) were 10478 and 7562mg/100g, respectively, and E/NE was 1.38. Among the EAA and NE, lysine (2110mg/100g)and aspartic acid (1924 mg/100g) were the most contents. Also, results showed that moisture,ash, protein and fat contents were 72.74, 1.8, 19.88 and 4.53%, respectively, in fresh roe. Theeffects of freezing and cold storage on the roes showed that UFA and SFA contents havereached to 49.83 and 48.07%, respectively, at the end of cold storage. It indicated that thesecompounds change to each other during frozen storage. Also, n-3 and n-6 series of fattyacids were 32.75 and 1.61% in fresh roe. But their contents decreased to 22.96 and 1.25% atthe end of period. Among the fatty acids, 22:6 and C16:0 had the most changes. The changesof fatty acids were significantly at 95% level except for C15:1, C18:3(n-3) and C20:4(n-6).All of the amino acids decreased in frozen storage and their changes were significantly(P〈0.05). EAA was 7818 mg/100g and E/NE was 1.27 at the end of storage period. Amongthe amino acids, leucine and lysine had the most changes. Moisture, ash, protein and fatcontents were 70.13, 1.82, 19.4 and 6.51%, respectively, at the end of storage period. Theperoxide value and T.V.N. increased during storage. So that, their contents have reached to5.86 mg/kg and 26.37 mg/100 g, respectively, at the end of frozen storage. The best shelf lifeof Thunnus tonggol roe was 6 or 7 months, because of lipid oxidation and increasing ofperoxide.

Description: PhD

Description: Advisors: S. Moeini Counsellors: A. Keyvan, M. Yousefian

Description: Fish protein concentrate (FPC) is a healthy, sustainable and high nutritiveproduct which sanitized produced from fishes in which, protein and othernutrients are more concentrated than in fresh fishes.The aim of this research is to study on the sustainability of FPC producedfrom Kilka (Clupeonella engrauliformis , C. grimmi and C. cultriventris)in two Vaccum Packaging and Modified Atmosphere Packaging atdifferent environmental factors during six months.In our study the analysis of FPC protein showed 91.2%, lipid: 0.5%, ash:3.6%, moisture: 2.3%, Total Volatile Nitrogen: 10 ml/100gr andperoxide: 5meq/kg. Amino acids and fatty acids were also determined.Bacteria and Fungi were lower than 1000 colony. Samples are kept indifferent condition of temperature (5, 20 and 35 degree centigrade),humidity (25, 40 and 90 percent) and light and dark environment in sixmonth.Lipid rate in FPC after 6 months in VP and MAP (60% C02, 30 % N2 and10% O2), packages was decreased but was not significant (P〉0.05). It wasalso detected that increase temperature lead to more decrease in lipidcontent. Protein rate of FPC was decreased from 91.2% to 73.6% duringsix months at 35°C in VP Package and from 91.2% to 69.4% in MAPpackage. These changes were significant (P〈0.05). TVN and PV rate inFPC after 6 months in VP and MAP packages was increased but wassignificant (P〈0.05). Amino acids and fatty acids were also determined.But more changes in MAP packages was detected.

Description: PhD

Description: Advisors: Abbas Ali Motalebi Counsellors: Wadud Rzvylar, Aliasghar Khanipoor. The full text document is in Farsi only so it has not been possible for AC Editors to check the metadata input.

Description: At the fishing season, in 2000, samples of species persian sturgeon (A. persicus), Severjuga (A. stellatus) and Mullet (L. aurata), were caught from the southern coasts of Caspian Sea and were freezes and preserved in the cold storage for one year They have also become biometery. The tissue's fillet were identified in order to determined the Fatty Acids. This was done during one year, frequently, fresh, two weeks after freezing and then monthly, respectively. So, after the extraction of lipids from the tissues and methylation, was injected to the gas-liquid Chromatography. After calibration, identified Fatty Acids were compared with standards according to their Retention Times. Peroxid value, lipid content and humidity were controlled. The unsaturated Fatty acids had The most amount, and a plenty of Polyunsaturated Fatty acids (PUFA) were observed, so that linoleic (C18:2), a-linolenic (C18:3), Arashidonic (C20:4), EPA (C20:5) and DHA (C22:6) Fatty acids had high amounts. The w-3, PUFA were more in comparison with w-6. The effects of freezing and cold storing on the fish fatty acids , were evaluated by the statistical tests , like SPSS, Tukey, Homogenous and Anova, and showed that in some species, a group of Fatty acids, specially PUFA, had some variation. The peroxide value that indicates the lipid deterioration, increased during toring. So, the best term if preserving in the cold storage, were determined and their Nutrition value and Medical applications due to their consumption were investigated.

Description: PhD

Description: Advisors: Sohrab Moeini Counsellors: Amin Keyvan, Mehdi Yousefian

Description: Biodegradable protein-based film was developed by incorporating cinnamon essential oil(CEO) into whey protein concentrate (WPC) at level of 0.8% and 1.5% v/v. Then physicaland mechanical properties of the films were evaluated. Adding CEO to the WPC matrixdecreased the water vapour permeability of the films and water solubility. Films containingCEO showed significant antibacterial activity both gram-positive and gram-negative strainsand exhibited significant inhibitory effect on the studied fungi. In continue, the effect ofwhey coating and whey coating incorporated with 1.5% CEO on quality and shelf life ofHuso huso fillet during refregrated (4±1°C) storage period were also investigated. The controland treated fish samples were analyzed for microbiological (total viable count, psychrophiliccounts), chemical (PV, TBA, FFA, pH, TVB-N), and sensory characteristics in 4-dayintervals up of microbial, chmical and sensoy analyses indicated lower levels of PV, TBA,FFA, pH, TVB-N in coasted sampels and specially, those with CEO while were kept inrefrigerator. Based on results, whey protein edible coating contain 1.5% cinnamon essentialoil could enhance preserving ability Huso huso during storage cold.

Description: PhD

Description: Advisors: M. Rezaei Counsellors: M. Soltioni, A. kamali

Description: The ever-increasing population of the world and the growing need for animal protein has doubled the modern man’s demand for food. Additionally, the improvement in the general public health, and the worsening of environmental/ecological pollution have prompted today’s world to look for ways to procure healthy food. And one such attempt is the use of natural preservatives to decrease the bacterial load in foodstuffs, in other words, to increase their durability.This study evaluates the effects of different concentrations of Zataria multiflora Bioss (EO 0, 0.005, 0.015, 0.045, 0.135, 0.405%) and Nisin (0, 0.25, 0.5, 0.75 μg/ml) and storage time (9 days) on the growth of Lactococcus garvieae Ir-170A(856bp) alone, and their combination in a food model system (fillets of the rainbow trout (Oncorhynchus mykiss). Additionally, the growth of a sample of this bacteria in laboratory conditions was studied.The results of this study showed that different concentrations of Nisin had a significant impact (p〈0.05) on Lactococcus garvieae.With the value of t in 0.75 μg/ml, the effectiveness rose to 65.77%; the biggest effect on Lactococcus garvieae. And the effect at 4 0C exceeded 80C.The study has also demonstrated that all concentrations of Zataria multiflora Bioss were effective against Lactococcus garvieae. However, with the value of t at 0.405%, the effectiveness was 71.91%. This value had the biggest effect on Lactococcus garvieae. At 4 0C, the effect surpassed the one at 80C.The synergistic effects of the EO and Nisin showed that with the value of t at 0.405% EO and 0.75 μg/ml Nisin was 14.62% had the greatest effect on Lactococcus garvieae.In this study, multi-factorial effects for different concentrations of Zataria multiflora Bioss (EO 0, 0.005, 0.015, 0.0025%), three different concentrations of122Nisin (0, 0.25,0.75 μg/ml) and two different levels of PH (5.5 , 7) at two incubation temperatures (15,37) on logp% of Lactococcus garvieae during 43 days in BHI broth were evaluated. Most of the effects on Lactococcus garvieae occurred in PH 5.5 and at a temperature of 150C.

Description: PhD

Description: Advisors: Mehdi Soltani, A. Akhondzadeh Basti. counsellor: A. Kamali

Description: The main aim of this research was to identify fatty acids composition of Caspian sea of White fish Rutilus frisi kutum tissue and their changes during one year cold storage (-18Ċ).The secondary aim was to determine the changes of moisture, ash, protein, fat, and to investigate the effects of storage time on peroxide, TBAi, FFA, and extractability of myofibrillar proteins of the fish tissue during one year cold storage (-18 Ċ). 10 samples of (Rutilus frisi kutum) were randomly collected from Anzali landings. The samples were frozen at -30 Ċ and kept in cold storage at -18Ċ for one year. According to time table, the samples were examined. The results showed that 27 fatty acids were identified. The unsaturated fatty acids (UFA) and saturated fatty acids (SFA) were 74/09 and 21/63 %, respectively, in fresh tissue. So that DHA (C22:6) oleic acid (C18:1c) had high amounts (15/07 ,20/57 ) among the UFA and palmitic acid (C16:0) was the most (13/09 %) among the SFA. The effects of freezing and cold storage on fish tissue showed that UFA and SFA contents have reached to 58/79 and 22/17 %, respectively, at the end of cold storage. It indicated that these compound change to each other during frozen storage. Also ω-3 and ω-6 series of fatty acids was 24/22 and 15/56% in fresh tissue, but their contents decreased to 8/68 and 5/11% at the end of period. Among the fatty acids C22:6, C18:1c and C16:0 had the most changes. The changes of fatty acids were significantly at 95% level expected for C18:0. Results showed that moisture, ash, protein, and fat contents were 75/9±0/03, 1/28±0/012, 21/8±0/2, and 4/1±0/01 % respectively, in fresh tissue. The moisture, ash, protein, and fat contents were 72/3±0/04, 1/83±0/05, 1/91±0/01 and 19/9±0/01 % respectively, at the end of storage period. Lipid damage was measured on the basis of free fatty acids (FFA), peroxide value (PV), and Thiobarbituric acid index (TBA-i). PV, TBARS and FFA concentration of frozen Caspian Sea white fish stored at -18 Ċ the temporal variation of these three variables were statistically significant (p〈0.001). Results of White fish myofibrillar proteins showed aggregation of bound reduced for stored at 12 months. SDS-PAGE analysis revealed that, the intensity of the myosin heavy chain and actin bound was reduced with increasing storage time. SDS-PAGE patterns showed that myosin heavy chain was much more susceptible to hydrolysis than actin.Key words: Rutilus frisi kutum, frozen storage, ω-3, ω-6, protein myofibrillar

Description: PhD

Description: Advisors: Sohrab Moeini, Nasser Ghaemi Counsellors: A.K. Haghdost

Description: In this study microbiological , chemical quality and fatty acid composition ofgrass carp (Ctenopharyngodon idella) fillets treated by dipping in sodiumacetate (%1 and %3), nisin (% 0.1 and % 0.2) and combination of sodiumacetate and nisin was evaluated during 16 days of refrigerated of 4°CAntilisterial effect of nisin was enhanced with the increased concentration ofsodium acetate. At day 12 post storage, Listeria monocytogenese count washigher in the control group than the recommended value, however in sodiumacetate and nisin treated samples, the count was lower (5.17-5.91 log cfu/g).With increasing the concentrations of sodium acetate, mesophilic counts werelower. Regarding nisin, better results was obtained by applying %0.1 nisin.Greater inhibition of mesophile bacteria was observed when combinationtreatment was used. The number of lactobacillus was lower when higherconcentrations of sodium acetate and nisin were used.Total Volatile Nitrogen values at the end of the experiment were lower in thesamples treated with both nisin and sodium acetate and the better results wereobtained in combination treatments. Peroxide (PV) at the end of the experimentwas 1.9 meq/kg in control, and the lowest values were observed for thetreatments 3(%0 sodium acetate +% 0.2 nisin) and 9(%3 sodium acetate +% 0.2nisin) between 1.08 and 1.62 meq/kg without significant difference.Thiobarbituric acid (TBA) levels at the end of experiment have been shown tobe 0.46 mg malonaldehyde per kg in the control. On the other hand treatments 9had the TBA values of 0.19 mg malonaldehyde per kg which was significantlylower than that of control.Polyunsaturated fatty acids increased by increasing the sodium acetate dosesand instead saturated fatty acids and n-6/n-3 ratio decreased. The ratio ofUFA/SFA and also C22:6/C16:0 increased when a higher concentration ofsodium acetate has been used. The best result obtained by using 3% of sodiumacetate but no such relation with nisin was observed.

Description: PhD

Description: Advisors: Mehdi Soltani, Abolghasem Kamali Counsellors: Mohammad Reza Ghomi, Seyed Ebrahim Hoseini

Description: Effects of different thawing method i.e. in a refrigerator, in water, at air ambient temperature and in a microwave oven on proximate, chemical (PV, TBA, FFA, TVB-N, SSP, FA), biochemical (pH, WHC,ThL), microbial (total viable, psychrotrophic, coliform, Shewanella and yeast-mould count) and sensory analysis were carried out on frozen whole Caspian sea Kutum (Rutilus frisii kutum) and Rainbow trout (Oncorhynchus mykiss) carcasses. The values of ash, protein, SSP, WHC, PUFA, PUFA/SFA. EPA+DHA/C16:0, pH, and microbial count of thawed samples decreased significantly while fat, PV, TBA, FFA, TVB-N, SFA and MUFA increased compared to the fresh fish (unfrozen) as control samples. Also, sensory evaluation all of thawed samples showed a significant (p〈0.05) quality loss compared to the fresh fish as control samples. The lowest chemical and biochemical values as well as microbial growth were determined in water thawed samples. Therefore, based on this study thawing in water is most suitable for frozen whole rainbow trout.

Description: PhD

Description: Advisors: Masoud Rezaei, Mehdi Soltani Counsellors: Mohammad Haghighi, Reza Pourgholam

Description: There is an increasing demand in developing newer and safer methods in preserving food products.Among which herbal additives seem to attract evermore attention recently.the major advantage of herbal additives is due to their favorable aroma besides their antimicrobial effects and less expensive than chemical additives. Zataria multiflora Boiss is a native Iranian herb which is used vastly as a food preserver essential oils and also medical usage.Metabolites of harmless bacteria, such as Nisin are also known to be safe preservatives that have antimicrobial activity.However to establish the usefulness of natural antimicrobial preservatives, they must be evaluated alone and in combination with other preservation factors to determine whether there are synergistic effects in rigid media .In this study were evaluated the effects of different concentrations of Zataria multiflora (EO 0, 0.005, 0.015, 0.045, 0.135, 0.405 ,0.810 %) and Nisin(0, 0.15, 0.25, 0.75 μg/ml) and Storage time (up to 21 days) on growth of Staphylococcus aureus ATCC 6538 in a food model system(light salted fish of silver carp, Hypophthalmichthys molitrix).The results on growth of S. aureus were evaluated using SPSS 15.0 statistical software (SPSS 15.0 for windows, SPSS Inc.) and analyzed the logarithm of total count of the bacteria by Tukey Test. Results were considered statistically significant when P≤0.05.The growth of Staphylococcus aureus was affected significantly(P〈0.05) by EO and Nisin and also combinations of EO and Nisin.Samples treated with 0.135, 0.405 and 0.810% of thyme essential oil showed a significant decrease on the growth of the bacteria compared with an treated samples(P〈0.05). No significant difference was seen on the growth of S.aureus in samples treated with lower concentrations of Z.multiflora(below 0.045%) and untreated group(P〉0.05).The most inhibitory effects were seen in samples treated with 0.405% and 0.810% of thyme essential oil until 9 and 12 days after storage,respectively.Also there was significant inhibtory effect(P〈0.05) in different concentration of nisin on the organism compared with an treated samples.The synergism effects of the Eo and nisin on the growth rate of the bacteria was significant (P〈0.05) compared with untreated samples and samples treated with the Eo or nisin, only. Synergismic effects was observed at concentration of 0.405 and 0.810% of Z. multiflora essential oil with 0.25 μg/ml Nisin, respectively until 15 days after storage.As expected it is preferred to apply the least possible amounts of additives in food preserving that not only are effective and safe but are economically justifiable.

Description: PhD

Description: Advisors: Afshin Akhondzadeh Basti, Mehdi Soltani counsellors: Abbas Matinfar

Description: The present study aimed production of a new product with various texture and sensoryproperties in chase of the impetus for increasing human consumption considering suitableresources of Kilka fish in Caspian Sea. Following deheading, gutting, and brining, commonKilka were battered in two different formulations, i.e. simple batter and tempura batter, viaautomated predusting machinery and then, they were fried through flash frying for 30 secondsat 170°C in sunflower oil after they were breaded with bread crumbs flour. The products weresubjected to continuous freezing at -40°C and were kept at -18°C in cold storage for fourmonths once they were packed. Chemical composition (protein, fat, moisture, and ash), fattyacid profiles (29 fatty acids), chemical indices of spoilage (peroxide value, thiobarbituric acid,free fatty acids, and volatile nitrogen), and microbial properties (total bacteria count andcoliform count) were compared in fresh and breaded Kilka at various times before frying (rawbreaded Kilka), after frying (zero-phase), and in various months of frozen storage (phases 1,2, 3, and 4). Organoleptic properties of breaded Kilka (i.e. odor, taste, texture, crispiness,cohesiveness of batter) and general acceptability in the phases 0, 1, 2, 3, and 4 were evaluated.The results obtained from chemical composition and fatty acid profiles in common Kilkadenoted that MUFA, PUFA, and SFA were estimated to be 36.96, 32.85, and 29.12 g / 100glipid, respectively. Levels of ù-3 and ù-6 were 7.6 and 1.12 g / 100 gr lipid, respectively.Docosahexaonoic acid (20.79%) was the highest fatty acid in PUFA group. ù-3/ù-6 andPUFA/SFA ratios were 7.6 and 1.12, respectively. The high rates of the indices and highpercentage of ù-3 fatty acid in common Kilka showed that the fish can be considered asinvaluable nutritional and fishery resources and commonsensical consumption of the speciesmay reduce the risk of cardiovascular diseases. Frying breaded Kilka affected overall fat andmoisture contents so that moisture content in fried breaded Kilka decreased significantlycompared to raw breaded Kilka, while it was absolutely reverse for fat content. Overall fatcontent in tempura batter treatment was significantly lower than that of simple battertreatment (P≤0.05). Presence of hydrocolloids, namely proteins, starch, gum, and otherpolysaccharides, in tempura batter may prohibit moisture evaporation and placement with oilduring frying process in addition to boosting water holding capacity through confining watermolecules. During frying process, fatty acids composition of breaded Kilka with variousbatters changed so that rates of some fatty acids such as Palmitic acid (C16:0), Stearic acid(C18:0), Oleic acid (C18:1 ù-9cis), and linoleic acid (C18:3 ù-3) increased considerablyfollowing frying; however, ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios (Polyan index)decreased significantly after frying. ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios intempura batter treatment were higher than those of simple batter treatment which is anindicator of higher nutritional value of breaded Kilka with tempura batter. Significantelevations were found in peroxide, thiobarbituric acid, and free fatty acids in fried breaded Kilka samples compared to raw samples which points to fat oxidation during cooking process.Overall microorganism count and coliform count decreased following heating process. Bothbreaded Kilka samples were of high sanitation quality at zero-phase according to ICMSFStandard. The results acquired from organoleptic evaluation declared that odor, cohesiveness,and general acceptability indices, among others, had significant differences between thetreatments (P≤0.05). In all evaluated properties, breaded Kilka with tempura batter indifferent phases gained higher scores than breaded Kilka with simple batter. During coldstorage of various treatments of breaded Kilka, total lipid content, PUFA, MUFA, ù-3, ù-3/ù-6, PUFA/SFA, Polyen index decreased significantly. The mentioned reductions inaddition to significant elevation of spoilage indices, namely peroxide, thiobarbituric acid, andfree fatty acids, during frozen storage, indicate to oxidation and enzymatic mechanismactivity during frozen storage of breaded Kilka. Considering sensory evaluation at the end ofthe fourth month and TVB-N contents exceeded eligible rate in the fourth month, shelf life ofthe products during frozen storage was set to be three months at -18°C. The results obtainedfrom statistical tests indicate to better quality of breaded Kilka processed with tempura battercompared to simple batter in terms of organoleptic evaluation, spoilage indices, and highquality of fat in various sampling phases.

Description: PhD

Description: Advisors: Ali Asghar Khanipour, Mehdi Soltani Counsellors: Abbasali Motallebi, Abolghasem Kamali

Description: The purpose of this study, Evaluation the effect of Rosmarinus officinalis and Thymus vulgaris extracts on the stability of poly unsaturated fatty acids in frozen Silver carp minced. Treatments include:Treatment 1 - Control: frozen meat packaged in conventionalTreatment 2: Frozen Silver carp minced+Thyme 300 mg/kg in normal packagingTreatment 3: Frozen Silver carp minced+Rosemary 200 mg/kg in normal packagingTreatment 4: Frozen Silver carp minced+Rosemary compound (100 mg/kg) and Thyme(100 mg/kg) in normal packagingAfter rapid freezing of samples in the spiral freezer by individual quick freezing method, tomaintain the cold temperature (-18) °C were transferred. Sampling and measurements to determine the fatty acid profile of the zero phase beginning in the first month and then every ten days, and 15 days in the second month of the third month after the monthly test.Identifying, defining and measuring the fatty acid profile by gas chromatography was performed. In this study, levels of both saturated and unsaturated fatty acids in threeexperimental and one control were identified as follows:A: saturated fatty acids: Meristic C14: 0/Palmitic C16: 0/Hepta decaenoic C17: 0/Stearic C18: 0/Arashidic C20: 0/B:Mono unsaturated fatty acids: palmitoleic C16: 1-W7/Oleic C18: 1-W9/Gadoleic C20:1-W9C:Poly unsaturated fatty acids: Linoleic C18: 2-W6/α-Linolenic C18: 3-W3D:High unsaturated fatty acids: Arachidonic C20: 4-W6 Eicosapentaenoic acid C20: 5-EPA/W3 Docosahexaenoic C22: 6-DHA/W3Results of this study was to determine, Thyme and rosemary extracts containing silver carpminced stored in freezing conditions, Stability of different types of fatty acids, monounsaturatedfatty acids, poly-unsaturated fatty acids, omega-3 and omega-6 fatty acids are. So that none of the fatty acids measured were not significant 100% increase or decrease,While changes in the fatty acid oxidation during storage time is minimized. The resultsobtained from the fatty acid profiles and indicators of their and statistical tests show that treatment with rosemary extract More stable during storage (-18) ° C In comparison with the control and other treatments are shown; And at relatively low compared to othertreatments and control samples oleic acid and linoleic acid, palmitic more.According to studies,in Silver carp minced that containing rosemary extract, end of the storage period of six months. Were usable, so even rosemary extract the shelf-lifeexamples to increase more than six months.

Description: PhD

Description: Advisors: A. A. Motalebi Moghanjvqy, Seyed Ebrahim Hosseini Counsellors: Ali Asghar Khanipour, Mehdi Soltani

Description: Nisin is a widely used naturally occurring antimicrobial effective against many pathogenic and spoilage microorganisms. It has been proposed thatreduced efficacy of nisin in foods can be improved by technologies such as encapsulation to protect it from interferences by food matrix components. Theaim of this study was using of spray dried encapsulated nisin with zein in concentration of (0.15 and 0.25 g/kg) and sodium citrate (1.5 and 2.5%) and treatments with both of them to extent the shelf life of filleted trouts packagedby Modified Atmosphere Packaging (45% CO2, 50% N2 ,5% O2) and stored at 4±1 °C for 20 days. Furthermore, to evaluate the antimicrobial efficiency of encapsulated nisin and soudium citrate the trouts fillets was inoculated withStaphylococcus aureus as an index pathogenic bacteria. Assessment of chemical spoilage indexes such as (Proxide value, Thiobarbituric acid, total volatile basenitrogen and pH) , microbial parameters (Total Plate Count, Psychrotrophic count, Lactic acid bacteria count), Staphylococcus aureus cont in treatments which were inoculated with 5 logcfu/g of this bacteria and sensory evaluation of fillets including (smell, color, texture and total acceptability) was carried out indays of 0, 4, 8, 12, 16 and 20. The results revealed that treatment with both exposure of nisin and sodium citrate showed significantly lower chemicalspoilage indexes in comparison with controls (vaccum packed and MAP)(P〈0.05). Furthermore, (nisin 0.25 g/kg sodium citrate 2.5%) treatment whichwas exposed to the maximal level used of both materials was significantly thelowest treatment with (Proxide value, Thiobarbituric acid, total volatile basenitrogen and pH) of 9.95 (meq O2/kg) , 1.55 (mgMA/kg), 29.65 (mgN/100g) and 6.65 , respectively and according to the maximal recommended level of this indices , shelf life of fillets in this treatment was esstimated 20 days.The control(vaccum packed) treatment was significantly the highest treatment with (Proxide value, Thiobarbituric acid, total volatile base nitrogen and pH) of 15.17 (meq O2/kg), 3.03 (mgMA/kg), 38.4 (mgN/100g) and 6.95 , respectively and according to the maximal recommended level of this indices , shelf life of filletsin this treatment was estimated 11 days. Also, in microbial point of view (nisin0.25 g/kg- sodium citrate 2.5%) treatment was the lowest treatment with TotalPlate Count, Psychrotrophic count, Lactic acid bacteria count andStaphylococcus aureus count of 6.7, 6.83, 5.25 and 6.04 logcfu/g respectively,and conrol (vaccum packed) treatment was the highest treatment with 9.15, 9.41, 7.7 and 9.01 logcfu/g respectively. According to the lower results of chemicaland microbial indices and higher sensory evaluated scores assessed in this research for encapsulated nisin in comparison with free nisin , it was concludedthat encapsulation of nisin with zein capsules may improve the efficiency of nisin. The measuremented values of Mass yield, Total solids content of capsules, Encapsulation efficiency, In vitro release kinetics in 200 hour for encapsulated nisin in this study was 49.89, 62, 98.31 and 69% respectively and Encapsulated particle size was lower than 674.21 μm for 90% of particles. As a consequence, nisin , in particular encapsulated nisin, and sodium citrate alone or together with and Modified Atmosphere packaging might be considered as effective tools in preventing the quality degradation of the fillets, resulting in an extension of their shelf life.

Description: PhD

Description: Advisors: Seyed Ebrahim Hosseini, Aboulghassem Kamali Counsellorrs: Abbasali Motallebi, Resa Pourgholam

Description: We compare differences and similarities in the annual stratospheric HNO3 cycle derived from ground‐based measurements at the South Pole during 1993 and 1995, after correcting an error in earlier published profile retrievals for 1993 which led to under estimation of mixing ratios. The data series presented here provide profiling over the range ∼16–48 km, and cover the fall‐winter‐spring cycle in the behavior of HNO3 in the extreme Antarctic with a large degree of temporal overlap. With the exception of one gap of 20 days, the combined data sets cover a full annual cycle. The record shows an increase in HNO3 above 30 km occurring about 20 days before sunset, which appears to be the result of higher altitude heterogeneous conversion of NOx as photolysis diminishes. Both years show a strong increase in HNO3 beginning about polar sunset, in a layer peaking at about 25 km, as additional NOx is heterogeneously converted to nitric acid. When temperatures drop to the polar stratospheric cloud (PSC) formation range near the end of May, gas phase HNO3 is rapidly reduced in the lower stratosphere, although at least 2–3 weeks of temperatures ≤192 K appear to be required to complete most of the gas‐phase removal at the upper end of the depletion range (22–25 km). Despite a significant difference in residual sulfate loading from the explosion of Mount Pinatubo, there appears to be little gross difference in the timing and effects of PSC formation in removing gas phase HNO3 in these 2 years, though removal may be more rapid in 1995. Incorporation of gas phase HNO3 into PSCs appears to be nearly complete up to ∼25 km by midwinter. We also see a repeat of the formation of gas phase HNO3 in the middle stratosphere in early midwinter of 1995 with about the same timing as in 1993, suggesting that this phenomenon is driven by a repetition of dynamical transport and appropriate temperatures and pressures in the polar night, and not (as has been suggested) by ion‐based heterogeneous chemistry that requires triggering by large relativistic electron fluxes. High‐altitude HNO3 production peaks during a period of ∼20 days, but appears to persist for up to ∼40 days in the 40–45 km range, ceasing well before sunrise. This HNO3 descends rapidly throughout the production period, at a rate in good agreement with theoretically determined midwinter subsidence rates. As noted in earlier studies, later warming of this region above PSC evaporation temperatures does not cause reappearance of large amounts of HNO3, indicating that most PSCs gravitationally sink out of the stratosphere before early spring. We present evidence that smaller PSCs do evaporate to ∼1 to 3.5 ppbv of HNO3 in the lower stratosphere, however, working downward from ∼25 km as temperatures rise during the late winter. There is a delay of ∼15 days after sunrise before photolysis causes significant depletion in the altitude range below ∼30 km, where subsidence has carried virtually all higher‐altitude HNO3 by polar sunrise. Some continued subsidence and photolysis combine to keep mixing ratios less than ∼5 ppbv below 30 km until the final breakdown of the vortex in November brings larger amounts of HNO3 with air from lower latitudes.

Description: Published

Description: 17739-17750

Description: 5A. Ricerche polari e paleoclima

Description: JCR Journal

Description: [1] We present the first intercomparison between the two most comprehensive records of gas‐phase HNO3 profiles in the Antarctic stratosphere, covering the greater part of 1993 and 1995. We compare measurements by the Stony Brook Ground‐Based Millimeter‐wave Spectrometer (GBMS) at the South Pole with Version 5 HNO3 data from the Microwave Limb Sounder (MLS) aboard the Upper Atmospheric Research Satellite. Trajectory tracing was used to select MLS measurements in the 70°–80°S latitude band that sampled air observed by the GBMS during passage over the Pole. When temperatures were near the HNO3 condensation range, additional screening was performed to select MLS measurements that sampled air parcels within 1.5 K of the temperature they experienced over the Pole. Quantitative comparisons are given at 7 different potential temperature levels spanning the range ∼19–30 km. Agreement between the data sets is quite good between 465 and 655 K (∼20–25 km) during a large fraction of the year. Agreement is best during winter and spring, when seasonally averaged differences are generally within 1 ppbv below ∼25 km. At higher altitudes, and during summer and fall, the agreement becomes worse, and GBMS measurements can exceed MLS values by more than 3 ppbv. We provide evidence that differences occurring in the lower stratosphere during fall are due to lack of colocation between the two data sets during a period of strong poleward gradients in HNO3. Remaining discrepancies between GBMS and MLS V5 HNO3 measurements are thought to be due to instrumental or retrieval biases.

Description: Published

Description: id 4809

Description: 5A. Ricerche polari e paleoclima

Description: JCR Journal