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العنوان
QUALITY AND SAFETY OF SOME DAIRY PRODUCT WITH NATURAL FRUIT PREPARATIONS \
المؤلف
WAHDAN, AHMED HASSAN ALI.
هيئة الاعداد
باحث / أحمد حسن على وهدان
مشرف / رزق عزب عواد
مشرف / عثمان عبد العليم عيطه
مشرف / اسامة ابراهيم البطاوى
تاريخ النشر
2018.
عدد الصفحات
165 p. :
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
علوم وتكنولوجيا الأغذية
تاريخ الإجازة
3/4/2018
مكان الإجازة
جامعة عين شمس - كلية الزراعة - العلوم الزراعية
الفهرس
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Abstract

Due to the technological development in the field of food industry, in addition to the interest of health aspects in the recent period, and put strict condition on the export and import of food, there has been an attention to the role played of fruit preparations and their effects on the quality and safety of dairy food produced, fruit preparations used in dairy food industry are considered to be rich in nutritional value due to the protein content of high biological value, mineral and vitamins. This research aims to study the role played by fruit pulp and fruit preparations which may be added in the manufacturing of some dairy products (yoghurt and ice cream) and their effects on quality and safety of these food products. A full concept for applying Hazard analysis and critical control points (HACCP) during manufacturing stages of these products was also carried out. The present work was planned to study quality and safety of same dairy product with use natural fruit preparations and the study was contained three parts as follows:
Part I: Application of HACCP system in manufacturing procedure of strawberry fruit pulp and different strawberry fruit preparation
This part was carried out to evaluate the effect of fruit preparations ingredients in quality and safety of strawberry fruit preparations. All ingredients and the other materials were tested for its microbiological and chemical quality. The data obtained and recommended results can be summarized as follows:
1- Staph. aureus and Salmonella sp. were not detected in all tested raw materials used in fruit preparations manufacturing which effected the bacteriological quality of those materials.
2- The high bacteriological quality of water used in the processing line of manufacturing fruit preparation since the total plate count (T.P.C) was 5 log cfu/ml, furthermore, both of coliform and Salmonella sp. counts were not detected in all the tested water samples.
3- The high bacteriological quality of sugar (sucrose) used in the processing line of manufacturing fruit preparation since the coliform, E. coli and Staph. aureus were not detected in all tested sugar (sucrose) samples, and the average of total plate count in sugar samples were 1.9 log cfu/g.
4- The spore forming bacterial count were not detected in all raw materials used in the processing line of manufacturing fruit preparation.
5- No total plate count, yeast & molds and E. coli were found in all tested surfaces except of the mixer as recorded positive result of (T.B.C).
6- The surfaces of the mixer and injection tube as recorded positive result of yeast & mold. Furthermore, Salmonella was not detected in all tested surfaces.
7- Two workers (workers 2 and 6) from six tested workers with percentage of 33.33 % were positive for E. coli and Staph. aureus.
8- Therefore, hygiene and sanitation practices of workers in the use of new technology together with the personnel hygiene education is needed in order to improve microbial safety of strawberry fruit preparation production and sales.
9- It could be recommended that, the workers must be educated with personal hygiene and sanitation practices.
10- The contamination of strawberry fruit preparation from the environment at the point of sale or from scoop must be prevented.
11- Good post processing sanitary practices are important to prevent microbial contamination of strawberry fruit preparation and this need to be enforced by Food Regulations.
12- Salmonella were not detected in all tested strawberry pulp and different type of strawberry fruit preparation samples.
13- Counting of Staph. aurues has taken the same trend of E. coli and coliform.
14-The high microbiological quality of tested strawberry pulp and different type of strawberry fruit preparation samples could be due to a good organized system, hygiene and sanitation practices.
15- Application of Hazard analysis and critical control points (HACCP) during manufacturing stages of fruit pulp and fruit preparations products to identify the most important sources of pollution cleared three and tow critical control point (CCPs) in fruit pulp and fruit preparations respectively, which were (i) refining (ii) sterilization (iii) filling and (i) pasteurization (ii) detection of metal particles for fruit pulp and fruit preparations respectively.
Part II: Production and properties of fruit stirred yoghurt fortified with strawberry pulp and different types of strawberry fruit preparation
This part was carried out to evaluate the fruit stirred yoghurt fortified with strawberry pulp and different type of strawberry fruit preparations, different strawberry pulp preparations were added a rate of 12% (w/w) to different treatments (T2 to T7). Some chemical, microbiological properties and sensory quality of stirred yoghurt samples were evaluated. The data obtained and recommended results can be summarized as follows:
1- Fruit stirred yoghurt containing strawberry fruit pulp and different type of strawberry fruit preparation exhibited significant nearly total solids content than the same of control treatment.
2- There were no significant differences in fat content between control stirred yoghurt and other treatments.
3- Fruit stirred yoghurt containing different type of fruit preparation and fruit pulp exhibited significant lower protein content than that of control treatment.
4- Fruit stirred yoghurt containing fruit pulp and different type of fruit preparation exhibited significant lower ash content than that of control treatment.
5- Fruit stirred yoghurt without additives (control) had the highest pH value among all treatments and fruit stirred yoghurt with fruit pulp T1 (fruit yoghurt containing 6% sugar + 6% pulp) had the lowest pH value among all treatments.
6- Addition of fruit pulp and different fruit preparation in fruit stirred yoghurt caused the significant difference in pH value
7- Stirred yoghurt containing fruit pulp exhibited significant lower viscosity value than of control.
8- Number of lactic acid bacteria gradually decreased along the storage period reaching the minimum counts at the end of storage period.
9- Addition of fruit pulp and fruit preparation had significantly harmful effect on the lactic acid bacteria strains. The effect was more obvious with using fruit pulp than fruit preparation.
10- The results also revealed that, all yoghurt samples both plain and fruit stirred yoghurt contained the recommended levels of lactic acid bacterial count (106 -107 log cfu/g).
11- The results indicated that yeast and molds counts increased progressively during storage.
12- Pathogenic bacteria (Coliform bacteria, Salmonella spp. and Staphylococcus aureus) were not detected in all yoghurt samples either when fresher and during the refrigerated storage.
13- Sensory evaluation results showed that there were significant differences among all fruit stirred yoghurt samples.
14- The fruit stirred yoghurt samples containing fruit preparation had significantly higher flavor score, than the control treatment.
15- There was significant difference in body & texture score between all treatment samples.
16- Addition of fruit preparation and fruit pulp during fruit stirred yoghurt manufacture caused an improvement in body & texture properties in final product.
17- The fruit stirred yoghurt samples containing fruit preparation had significantly higher flavor score, than the control treatment.
18- Addition of fruit preparation in fruit stirred yoghurt manufacture caused a significant increase in fruit stirred yoghurt flavor scores.
19- The sensory scores of all the samples were decreased during storage period.
20- from such study, it could be reported that, strawberry fruit preparations as fruit for stirred yoghurt preferred rather than strawberry pulp. The viability of lactic acid bacteria strains in all yoghurt treatments during the cold storage than the recommended minimum levels by FAO/WHO (106 log cfu/ g).
21- So, fruit preparations could be used in stirred fruit yoghurt formulations for enhancing the quality and properties of the product compared with using fruit pulp especially nutritive value
Part III: Production and properties of fruit ice cream fortified with strawberry pulp and different types of strawberry fruit preparation.
This part was carried out to investigate the effects of adding fruit pulp and preparations in the base formula of ice cream on the acceptability and functional properties of resultant product. Different strawberry preparations were added a rate of 15% (w/w) to different ice cream treatments (D1 to D3). All mixes and resultant ice cream samples were evaluated for their chemical, physical and rheological properties as well as the sensory quality attributes. The data obtained and recommended results can be summarized as follows:
Fortification the ice cream mix with strawberry pulp and different type of strawberry fruit preparation had no significant effect in total solids and fat contents among all treatments.
1- All the mixes of ice cream fortified with strawberry pulp and different type of strawberry fruit preparation had lower protein and ash contents than that of control mix.
2- It is clear that, fortification the ice cream blend with strawberry pulp and different type of strawberry fruit preparation had significant effect on protein and ash contents in ice cream mix.
3- Values of pH significantly decreased with adding strawberry pulp and different type of strawberry fruit preparation in ice cream formula.
4- Freezing point of ice cream mixes was significantly affected with adding strawberry pulp and different type of strawberry fruit preparation.
5- The mixes showed lower freezing points by adding strawberry pulp and different type of strawberry fruit preparation into formula of ice cream mixes.
6- The results showed that, there were significant differences in freezing point between ice cream mixes made with strawberry pulp and other mixes made with strawberry fruit preparation.
7- The results indicated that, significant differences were observed between specific gravity of control ice cream mix and mixes containing strawberry pulp and different type of strawberry fruit preparation.
8- Control ice cream mix was the highest specific gravity value, while treatment D1 containing 15% strawberry pulp was the lowest specific gravity value among all treatments.
9- Addition of strawberry pulp and different type of strawberry fruit preparation to the ice cream formula decreased the specific gravity of mixes showing more decrease with adding strawberry pulp.
10- Weight per gallon of all ice cream mixes was closely related to their specific gravity.
11- It could be concluded that, incorporating different type of fruit preparation in strawberry ice cream mix resulted in higher specific gravity value of resultant ice cream.
12- The values of weight per gallon of ice cream product have taken similar trend as in specific gravity.
13- It is clear from the results that, overrun percent in ice cream was significantly affected by adding fruit preparations.
14- The data indicated that, there were differences in melting resistance between all ice cream treatments.
15- Strawberry ice cream product made with 15% strawberry fruit preparation congaing 40% sugar + 40 strawberry fruit + 3.5% biscuit (D3) had the fastest and highest meltdown (%) among all treatments.
16- Fortification of strawberry pulp and different type of strawberry fruit preparation increased the meltdown of ice cream treatments. So, the lowest meltdown was in ice cream made without strawberry pulp or different type of strawberry fruit preparation (control) among all treatments.
17- All fruit ice cream formulations with strawberry pulp or different type of strawberry fruit preparation showed higher melting than control.
18- Sensory evaluation results showed that there were significant differences among all ice cream samples.
19- The ice cream sample containing strawberry fruit preparation D2 that, formulated from 27% sugar and 53% strawberry fruits was significantly higher flavor score, than the control and other treatments.
20- Addition of strawberry fruit preparation in ice cream manufacture caused a significant increase in ice cream flavor scores.
21- There was no significant difference in body & texture score between control ice cream and other treatment.
22- Addition of fruit preparations containing 15 % fruit preparations (27% sugar + 53% strawberry fruits) during ice cream manufacture caused an improvement in body & texture properties of final product.
23- It’s clear from the results that, fortification the ice cream blend with strawberry fruit preparation caused a significant increase in color score of ice cream.
24- The highest total scores points were gained by (D2) fruit ice cream that fortified with 15 % fruit preparations (27% sugar + 53% strawberry fruits) followed by (D3) fruit ice cream containing 15 % fruit preparations (40% sugar + 40% strawberry fruits+3.5% biscuit).
25- On the other hand, the least total scores points were recorded for D1 ice cream that fortified with 15 % strawberry pulp.
26- In general, fortification the ice cream blend with fruit preparations increased acceptability of ice cream product.