Master Thesis      [Total: 55 ]

Incidence of spore-forming bacteria in certain dairy products , with emphasis on factors affecting their germination

Doaa Mousa, 2020

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The present study aimed to isolate and characterize strains of spore forming bacteria from traditional Egyptian dairy products. The study also examined the effect of nutrient factors on spores germination of spore forming bacteria isolated from Egyptian dairy products . An assessment of antibiotic response of spore forming isolates recovered from Egyptian dairy products has been also conducted. Results generated throughout this study can be summarized as follows:
Part One: Prevalence of spore-formers associated with milk and dairy products processing in Mansoura city.
• Ninety samples of traditional milk and dairy products were randomly collected from local markets in Mansoura city. These samples included 30 raw milk samples, 15 UHT milk samples, 15 skim milk powder samples, 15 Ras cheese samples and 15 Domiati cheese samples
• The total viable count of raw milk samples were ranged from 10.06 to 10.66 log cfu/ml. The total viable counts of Ras cheese and Domiati cheese varied from 8.78 to 9.35 and 9.28 to 9.65 log cfu/ml, respectively. The total viable count of skim milk powder was ranged from 4.00 to 4.87 log cfu/ml.
• Out of 388 suspected isolates, 87 isolates were identified as potential aerobic spore forming bacilli. These results could present contamination of milk and dairy product plants with aerobic spore forming bacteria that exist in raw milk may resist the effect of pasteurization and other processing factors until they reached to final products. Out of 87 potential spore forming isolates 5 isolates generally regarded as facultative anaerobes and could not hydrolyze starch (Group I), 37 isolates were also regarded as facultative anaerobes and could be able to complete starch hydrolysis, these isolates are considered to be a members of (Groups II), (Group III)includes strict aerobes and has not ability to hydrolyze starch representatives of 23isolates. However 22 isolates belong to as members of (group IV) that presents strict aerobes and has ability for starch hydrolysis.
• Confirmed group 1 isolates examined the capability of these spore forming isolates to ferment citrate, mannitol and maltose in addition examining the ability of these strains to reduce nitrate and gelatin hydrolysis.
• Confirmed group 2 isolates examined the capability of these spore forming isolates to ferment lactose, hydrolyze gelatin and casein, reduce nitrate to nitrite, form sporangium bulging and grow at 50°C.
• Confirmed group 3 isolates examined the capability of these spore forming isolates to hydrolyze gelatin and urea, form sporangium bulging and grow at both 37 °C and 50°C, in addition to oxidase production.
• Confirmed group 4 isolates examined the capability of these spore forming isolates to ferment rafinose and citrate, form sporangium bulging and grow at 50°C.
• API 50 CHB is specified for the characterization of Bacillus and related genera. Isolates were identified as B. cereus, B. subtilis, B. mycoides, B. pumilus, B. weihenstephanensis, B. thuringiensis, B. coagulans, B. sphaericus and B. licheniformis. The efficiency of API system for spore forming bacteria was approximately 80%. The API system could not was able to identify B. thuringiensis (4 isolates).


STUDIES ON MODIFIED BUFFALOESES MILK FAT

TAMER ABDUL ALIM, 2020

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In recent years, most industrialized countries and developed countries have decreased consumption of butter and fatty products produced from buffaloes milk due to their negative effects on health aspects of serious diseases such as atherosclerosis and obesity, as well as some technological characteristics of these products when consumed such as Poor Spreadable, therefore this study aimed to modify the chemical composition of buffaloes milk fat by using crystallization to separate the fractions of fat in different temperatures. The study included the following points:
1. Improving the functional properties of Buffaloes Butter Oil Fractions obtained by Multi-Step Dry Fractionation
In this study, buffaloes butter oil was used in the preparation of milk fat fractions (high - medium - low melting point) solid and liquid in a multi-step crystallization method at temperatures 35, 25, and 15OC depending on the melting point, and obtained three solid fractions S15. S25, S35 and three liquid fractions L15, L25 and L35. Some of the physiochemical and chemical properties and oxidation stability and microscopic microstructure were studied by confocal microscope and Different Scanning Calometric (DSC) and the results obtained were as follows:
1. The higher content of L15 was 66.42% from the original L25.
2. The ratio liquid and solid fraction was 45.33:54.67, 58.88:41.12 and 66.42: 33.58 at 25, 35 and 15OC, respectively.
3. SMP was recorded 36.54OC for BO, while resulted fractions descended in order as follows: 39.76, 36.30. 32.36 ,26.83 .22.46 and 13.37?C for S35, S25, L35, L25, S15, and L15, respectively.
4. The high number of iodine (IV) for low-melting fat fraction S15 and L15 reaches (38.65 and 43.87) compared to butter oil (BO) and other fractions.
5. The concentration of cholesterol in liquid fraction was significantly (P?0.05) higher than that of solid fractions. About 95.39% of total cholesterol was recorded in L15, whereas, in S15 was 76.45%.
6. The OSI oxidation stability index of butter oil was higher compared to the obtained fractions, as it reached 9.30 hr while it reached 4.65 hr in L15.
7. The palmitic and stearic fatty acids (C18:0, C16:0) content was reached in HMF (S35) being 35.47 -14.942 mg/100gm respectively, while the oleic fatty acid content (C18:1) was the highest which ranged between 33.17-35.53 mg/100gm in S15 and L15, respectively.
8. The ratio of the omega-6 to omega-3 (?6:?3) was increased with decreasing Atherogenicity index (AI) in obtained fractions.
9. The DSC curve for butter oil (BO) showed 2 exothermic curves at low temperature 20.42OC, the first abroad curve and at 18.96OC for the second curve.
10. HMF (S35) exothermic peaks temperatures tended to rise to 33.79OC for the first curve and 4.31OC for the second curve, while


SYNTHESIS AND CHARACTERIZATION OF SOME NEW ORGANO-COMPLEXES CONTAINING PYRIDOPYRAZOLOPYRIMIDINE DREVATIVES AND SOME THEIR APPLICATIONS ON SOME DAIRY PRODUCTS

Nour Said Shams El-Din, 2020

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The present work is concerned with synthesis and characterization of new transition metal complexes with three organic ligands H2L1, H2L2 and H2L3 which donated )I, II, III( respectively having N, O donar atoms.
This thesis consists of three main chapters in addition to application part as well as English abstract, Arabic abstract and references.
The first chapter embraces on introduction on the nature and importance of the ligands for synthesis the metal complexes as well as literature survey was reported.
The second chapter is experimental part which describes the methods for preparation of organic ligands and transition metal complexes. It is also represents the different chemical, experimental tools and equipments used for preparation of this work.
The third chapter comprises the results of characterization and discussion of the obtained complexes using physico-chemical methods such as elemental analysis, spectroscopic (IR, UV), molar conductivity, magnetic moment measurements, thermal analysis and finally an applied part which were classified into two parts the first part, includes the biological activity where, because of the wide range of activities of pyridopyrazolopyrimidine drevatives, we have been interested on the most safe complexes of pyridopyrazolopyrimidin drevatives in this work which are donated (Ib, Ic, Id, IIa, IIIa) then study them as a new class for the anticancer therapy (i.e. anti leukemia) and also investigate the antimicrobial activities of pyridopyrazolopyrimidine drevatives (I, II, III) and of their metal complexes (Ia-If, IIa, IIb, IIIa, IIIb) and finally the second part contains some properties of the fermented milk (Laban Rayeb) after addition of copper and cobalt chloride complexes (Ia, Id, IIa, IIb, IIIa, IIIb) on it.


The economical Evaluation to the current and Future situation of the Nutritional Agricultural Industries

samah ibrahim, 2020

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The trend towards food processing projects is considered one of the best and most appropriate economic solutions for preserving and marketing agricultural production. Mainly, the food industries include many projects that the national economy depends on and included in the industry of jams and juices, which in its content represent a recent trend that has a large marketing segment in the local markets and also for export and the proposed project is considered one of the projects that complements the economic system of agricultural or rural areas in general and areas of agricultural land reclaimed in particular. The problem of the study is limited to wide fluctuations in demand for industries based on crops Vegetables as a result of price differences that have emerged recently as a result of the rise in prices of most agricultural crops, especially in vegetable crops that are particularly damaged, and this effectively affects marketing efficiency, and the manufacturing process becomes an urgent necessity to reduce losses and damage and reduce fluctuation in prices and availability of thؤe commodity, and benefit Among the many advantages with regard to vegetable crops through the tendency to manufacture products and the rise in the level of their quality and specifications of their production in line with the needs of the local market and the requirements of the global market and the extent of their economic quality and financial value. The study aims in general to the economic and financial evaluation of the current and future situation of the agri-food industries, it was found through the development of the total area of tomatoes in Egypt during the period (2002-2017), where the minimum total area of tomatoes reached about 396 thousand acres during the year 2017 while the maximum reached About 600 thousand feddans in 2009 with an average of about 497 thousand feddans. In studying the development of the total production of tomatoes in Egypt during the period (2002-2017), as the minimum total production of tomatoes reached about 6723 thousand tons during 2017, while the maximum amount reached 10279 thousand tons in 2009 With an average of about 8,170,000 tons, tomato productivity has improved in Egypt For the period (2002-2017), where the minimum productivity of tomatoes reached about 14.9 tons during 2002, while the maximum reached about 17 tons in 2017, with an average of about 16 tons, during the period (2002-2016) where it reached the minimum revenue acres of tomato in Egypt about 6972 pounds in 2002, while about 30 547 pounds in 2011 reached an average of about 17740 pounds with standard deviation around 8696.5 pounds , the total revenue of tomato acres in Egypt during the period (2002-2016) where the minimum income for tomato acres in Egypt reached about 6972 pounds during the year 2002, while the maximum amount was about 30,547 pounds in 2011, with an average of about 17740 pounds, with a standard deviation of about 8696,5 pounds, The total costs of tomato acres developed in Egypt during the period (2002-2016), as the minimum cost of tomato acres in Egypt reached about 2981 pounds during 2002, while the maximum amount reached about 8267 pounds in 2016, with an average of about 4460 pounds, and the return of the pound invested in tomato production in Egypt during the period (2002-2016), as the minimum return on the invested fairy was reached Tomato production in Egypt was about 1.3 pounds during 2002, while the maximum level reached about 5.8 pounds in 2009


A STUDY ON THE CHEMICAL AND RHEOLOGICAL PROPERTIES OF PROCESSED CHEESE

MAMDOUH DAWOUD, 2020

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Part (1) of the present study concerned with analysis of market processed cheese since a total of 48 processed cheese spread (PCS) samples representing 16 brands were randomly collected and tested for composition and some properties. This was also carried on 30 processed cheese block (PCB) samples representing different 10 brands located in the Egyptian market.


Effect of Different Milk Types on Physicochemical and Rheological Properties of Stirred Greek-Style Yoghurt

Meselhy Meselhy Ahmed, 2019

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Yoghurt (yogurt) is one of the most famous dairy products in the world. Yoghurt is widely accepted by the consumer due to its health benefits and basic nutrition. Greek-style yoghurt, also known as "concentrated yoghurt", it has the following traditional processing of yoghurt which is then concentrated again. Intensive stress removes a large amount of whey and sugar, which changes the nutritional and sensory properties of the yoghurt. Greek yoghurt has a more refreshing taste and creaminess texture. This study investigated the approach to developing a Greek yoghurt formulation using different fresh milk types (buffalo milk, cow milk, skimmed fresh cow milk), and adjusting the chemical properties using milk protein concentrate, skimmed milk powder, cream, modified starch and strawberry fruit preparation to produce a recombined acid milk gel with physicochemical and rheological aspects similar to those found in commercial Greek-style yoghurt.


Chemical and Technological Studies on Beef Sausages Fortified with Flaxseed and Chickpea

Zeinab Salam Gad, 2019

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This study was aimed to preparation of beef sausages by replacement of beef meat by (10%) milled flaxseed or (20%) chickpea flour and addition of (2%) pomegranate peel powder, and studying the quality properties of the prepared products. Besides studying the quality properties during cold storage at 4± 1?C for three weeks as well as frozen storage at -18±1?C for three months.
The most important obtained results could be summarized as follows:
Replacement of beef meat by (10%) milled flaxseed for preparing beef sausages
• Improved the proximate composition by increasing significantly the crude fat, crude fiber, carbohydrate contents as well as the caloric value.
• Improved the physiochemical properties which increased the cooking yield and the water holding capacity whereas decreased the cooking loss and shrinkage.
• Increased the poly unsaturated fatty acids content.
• Reduced the total bacterial count, yeasts and mold count compared with control.
• Affect significantly on sensory evaluation of the final product at zero time but during frozen storage these affect was not significantly.
• Finally it reduced the final coasts by 8.3 %.
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Replacement of beef meat by (20%) chickpea flour for preparing beef sausages
• Improved the proximate composition by increasing the crude fiber and carbohydrate contents but, decreasing the fat and ash contents as well as the caloric value.
• Affected the physiochemical properties which decreased the cooking loss and shrinkage but increased the water holding capacity, cooking yield.
• Incorporating of chickpea flour improved the fatty acids profile.
• Reduced the total bacterial count, yeasts and mold count compared with control.
• On significant between control and the prepared product overall acceptability.
• Finally it reduced the final coasts by 16%.
Addition of (2%) pomegranate peel for preparing beef sausages
• Increased the ash, and carbohydrate contents while decreased moisture and protein contents.
• Decreased the TBA value and peroxide value in control and treated products.
• Decreased the total bacterial count, yeasts and mold count in control and treated products.
• Improved the sensory evaluation of the prepared beef sausages.
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Effect of cold storage (4 ± 1°C) for three weeks of the prepared beef sausages
• Decreased the moisture, protein contents while increasing the crude fat, ash and carbohydrate contents as well as the caloric value.
• Affected the physiochemical properties which increased the cooking loss shrinkage, TBA value, peroxide value and decreased the water holding capacity, cooking yield in control and all treated products..
• Increased the total bacterial count, while yeasts and mold were observed in the second week of storage in control and all treated products.
• Significantly decreased the sensory evaluation in control and all treated products.
Effect of frozen storage (-18 ± 1°C) for three months of the prepared beef sausages
• Decreased the moisture, protein contents while increasing the crude fat, ash and carbohydrate contents as well as the caloric value.
• Affected the physiochemical properties which increased the cooking loss, shrinkage TBA value, peroxide value and decreased the water holding capacity, cooking yield.
• Decreased the total bacterial count, while, yeasts and mold were not detected in control and all treated products.
• Decreased un significantly the sensory evaluation in control and all treated products.


Chemical and Technological Studies on Chicken Burger

Zeinab Ahmed Heikal, 2019

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This study was aimed to preparation of chicken burger by replacement of chicken breast meat by (10%) wheat germ flour or (30%) steamed pumpkin pulp and addition of (1%) rosemary powder, and study the quality properties in the prepared products. Besides studying the quality properties during cold storage at 4± 1?C for three weeks as well as frozen storage at -18±1?C for three months.
The most important obtained results could be summarized as follows:

Replacement of chicken breast meat by (10%) wheat germ flour for preparing chicken burger:

• Improved the proximate composition by increasing significantly the crude fat, crude fiber, carbohydrate contents as well as the caloric value.
• Improved the physio-chemical properties which increased the cooking yield and the water holding capacity whereas decreased the cooking loss and shrinkage.
• Increased the poly unsaturated fatty acids content.
• Reduced the total bacterial count, yeasts and mould count compared with control.
• Not affect significantly on sensory evaluation of the final product.
• Finally it reduced the final coasts by 7.1%.

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Replacement of chicken breast meat by (30%) pumpkin pulp for preparing chicken burger:

• Improved the proximate composition by increasing the ash, crude fiber and carbohydrate contents but, decreasing as well as the caloric value.
• Affected the physio-chemical properties which increased the cooking loss and decreased the water holding capacity, cooking yield and shrinkage.
• Incorporating of pumpkin pulp improved the fatty acids profile.
• Reduced the total bacterial count, yeasts and mould count compared with control.
• Improved the sensory evaluation of the final product compared with control.
• Finally it reduced the final coasts by 27%.

Addition of (1%) rosemary for preparing chicken burger:


• Increased the ash, and carbohydrate contents while decreased moisture and protein contents.
• Improved the physiochemical properties which increased the cooking yield and the water holding capacity whereas decreased the cooking loss and shrinkage compared with control.
• Decreased the TBA value and peroxide value in control and treated products.
• Decreased the total bacterial count, yeasts and mould count in control and treated products.
• Decreased un significantly the sensory evaluation at zero time and during storage
Effect of cold storage (4 ± 1°C) for three weeks of the prepared chicken burger:
• Decreased the moisture, protein contents while increasing the crude fat, ash and carbohydrate contents as well as the caloric value.
• Affected the physio-chemical properties which increased the cooking loss, shrinkage, TBA value, peroxide value and decreased the water holding capacity as well as cooking yield in control and all treated products.
• Increased the total bacterial count, while yeasts and moulds were observed in the second week of storage in control and all treated products.
• Significantly (p < 0.05) decreased the sensory evaluation in control and all treated products.

Effect of frozen storage (-18 ± 1°C) for three months of the prepared chicken burger:
• Decreased the moisture, protein contents while increasing the crude fat, ash and carbohydrate contents as well as the caloric value.
• Affected the physio-chemical properties which increased the cooking loss, shrinkage TBA value, peroxide value and decreased the water holding capacity, cooking yield.
• Decreased the total bacterial count, while, yeasts and moulds were not detected in control and all treated products.
• Decreased un significantly the sensory evaluation in control and all treated products


Technological and chemical studies on some tomatoes products

Mohamed Ramadan, 2019

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We neglected very important bio-active tomatoes products and it must be use the high amount producing of tomato in Egypt, since tomato had short shelf life. Throughout, it was processed new products for direct uses in prepared some food meals with preserving most of high nutrition value. Alisa cultivar was used in this study, since it had the best attributes for drying and canning such as firmness, maturity and more pulp, in addition decreased amount of seeds. So, it helped to industry products had good quality.


UTILIZATION OF GRAPE PROCESSING WASTES IN SOME CHICKEN PRODUCTS

Zeinab hassan ahmed, 2019

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In this study, ethanol (50 and 100%), methanol (70 and 100%), acetone (70 and 100%), chloroform 100% and water extract of grape seeds were evaluated for their antioxidant and antimicrobial activities. Extraction yield of grape seeds ranged from 6.0 to 14.50% depending on organic solvent type. Grape seed methanol 70% and ethanol 50% extract had significantly higher total phenolic (9.501 and 8.949 mg gallic acid/g), total flavonoids (6.707 and 6.398 mg quercetin /g) and antioxidant activity (702.37 and 636.50 µMolTrolox eq/gm), respectively than other grape seed extracts. While, grape seeds water extract showed the lowest total phenolic, flavonoids compounds and antioxidants activity. Twenty one phenolic and nine flavonoid compounds were identified by HPLC technique in each one of grape seed extracts


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