الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 179 |  |  |
| | | from | 179 | | |
Abstract
Over recent years, the food industry has been undergoing major changes. To meet growing variations in demand and increasingly specific requirements from consumers, the food industry needs to display a huge capacity for innovation. Nowadays, food products must always be safe and must meet nutritional and health requirements. Functional foods have recently emerged as a novel sector of health-enhancing products, functional foods are diverse groups, including conventional foods, such as traditional and functional bio-yoghurt, or they can be specifically enhanced, such as fortified drinking bio-yoghurt with fruit pulp as a source of antioxidant. This research aims to study improving the properties of traditional yoghurt and functional bio-yoghurt by producing them using a mixture of goat’s and cow’s milk in different ratios and different types of starter cultures used and production of new functional flavored drinking yoghurt fortified with blueberry and guava pulp extracts as a source of antioxidants and study the potential utilize consequences and implications of the incorporation method on the properties of the final formulated product and the study contained three parts as follows:
Part I: Production and properties of traditional yoghurt made using mixture of goats and cows milk in different ratios.
This part of the study was planned to produce a valued product such as a traditional yoghurt product using a mixture of cow’s and goat’s milk in different ratios 100:0, 75:25, 50:50, 25:75 and 0:100%, respectively, with the use of the typical starter culture. Some physiochemical, functional, microbiological, rheological and sensory properties of different traditional yoghurt samples were determined. The data obtained and recommended results can be summarized as follows:
1- Some physiochemical properties of pure cows and goats milk used in experimental manufacture and production procedures. The data showed
2- that there were significant differences found in average fat, ash and lactose contents between the pure, goats and cows, milk samples.
3- The milk gross composition of, dairy goats was slightly affected by grazing on desert herbs, while dairy cows was slightly affected by grazing on natural local grass.
4- There were no significant differences found in average acidity content and pH value between the pure, goats and cows, milk samples.
5- The values of titratable acidity are also within the range, 0.16 to 0.18%, which may be obtained from good quality fresh milk suitable for the processing of yoghurt manufacture.
6- Some physiochemical properties of different traditional yoghurt made using mixture of goats and cows milk in different ratios. The data showed that there were significant differences between all traditional yoghurt samples in fat, ash and lactose content.
7- The data stated that the lowest fat and ash values and the highest lactose value in the case of cows milk yoghurt (control) were linked to fat, ash and lactose content levels in cow’s milk.
8- Increasing the goat milk ratio in the mixture caused fat and ash percentages upward while lactose percentages downward until get to the highest fat and ash values and the lowest lactose value in case of goats milk yoghurt (control) linked to fat, ash and lactose content levels in goats milk it could be reported that fat, ash and lactose content of the traditional yoghurt mixes of goats and cows milk in different ratios were originally affected by the formula contents of fat, ash and lactose in the production process.
9- The traditional yoghurt mixes of goats and cows milk in different ratios exhibited no significant differences along all traditional yoghurt formulations (with mixing cows and goats milk) compared of control samples (pure cows and goats milk yoghurt) in total solids and protein content.
10- The data revealed that traditional cows milk yoghurt (control) had lowest total solids value and highest protein value while traditional goats milk yoghurt (control) had highest total solids value and lowest protein value among all treatments.
11- Add goats milk with cows milk in traditional yoghurt mix had no significant effect on acidity percentage.
12- The data revealed the traditional yoghurt treatment prepared using goat and cow milk in a combined ratio 25:75 had highest titratable acidity among all treatments.
13- Traditional cows milk yoghurt 0:100 ratio had the highest titratable acidity followed by the traditional yoghurt formulations prepared using goat and cow milk in combination ratios 25:75, 50:50 and 75:25 thereafter the traditional goats milk yoghurt 100:0 ratio had the lowest titratable acidity which could be explained by the enhancement of the microbial growth and acidity progress of lactic acid bacteria in cows milk than in goats milk, as a result of lower affected water and lactose, percentage of goats milk than of cows milk.
14- The titratable acidity of all the samples were increased during storage period.
15- Mixed the cows with goats milk, in traditional yoghurt mix had no significant effect on pH values.
16- The data revealed the traditional yoghurt treatment prepared using goat and cow milk in a combined ratio 75:25 had highest pH values among all treatments.
17- Traditional goats milk yoghurt (control) had the highest pH value then an increase in pH value while raising the proportion of goat’s milk in the traditional yoghurt samples while cows milk yoghurt (control) had the lowest pH value among all treatments this may be due to that the goat’s milk used in the experiment basically higher than cow’s milk in the pH values.
18- The pH value of all the samples were decreased during storage period.
19- The differences were not statistically significant in syneresis of traditional yoghurt made using mixture of goats and cows milk in different ratios compared of control traditional yoghurt treatments.
20- Traditional cows milk yoghurt (control) had the highest susceptibility to syneresis values followed by the traditional yoghurt formulations prepared using goat and cow milk in combination ratios 25:75, 50:50, and 75:25 thereafter the traditional goats milk yoghurt (control) had the lowest susceptibility to syneresis values may be due to that determined of syneresis value by means of drainage method varied according to the milk type used for yoghurt manufacture, therefore an increase in the proportion of goat’s milk in the formulations leads to a rise in its pH value, which is followed by a decrease in the syneresis rate.
21- The susceptibility to syneresis values slightly increased in all treatments as the refrigerated storage period progressed up to 14 days.
22- Mixing the goats milk with cows milk in the traditional yoghurt mixture had a significant effect on the lactic acid bacteria growth.
23- Traditional goats milk yoghurt (control) was the lowest lactic acid bacteria, while Traditional cows milk yoghurt (control) was the highest lactic acid bacteria, among all treatments.
24- Number of lactic acid bacteria gradually decreased along the storage period reaching the minimum counts at the end of storage period.
25- The results indicated that Yeasts & Moulds counts increased progressively during storage after 7 days.
26- Coliform bacteria were not detected in all traditional samples either when fresher and during refrigerated storage.
27- Sensory evaluation results showed that there were significant differences among all traditional yoghurt samples except for appearance score.
28- Total scores were slightly decreased during the storage period.
29- The data revealed the traditional cows milk yoghurt treatments had highest total score among all treatments followed by traditional yoghurt formulations prepared using goat and cow milk in combination ratios 25:75 treatment.
30- from this study, utilizing of goats milk by blending with cows milk up to a ratio of 1:1 could be used by the industrial sector for economic and technological advantages in production of accepted traditional yoghurt.
Part II: Production and properties of functional bio-yoghurt containing different levels of goats milk as cows milk substitute.
This part of the study was planned to produce a valued product such as a functional bio-yoghurt containing different levels of goats milk as cows milk substitute in ratios 0:100, 25:75, 50:50, 75:25 and 100:0%, respectively, with the use of the probiotic starter culture (ABT-5). Some physiochemical, functional, microbiological, rheological and sensory properties of different functional bio-yoghurt samples were determined. The data obtained and recommended results can be summarized as follows:
1- Some physiochemical properties of different functional bio-yoghurt containing different levels of goats milk as cows milk substitute. The data showed that there were significant differences between all functional bio-yoghurt samples in fat, ash and lactose content.
2- The data stated that the lowest fat and ash values and the highest lactose value in case of cows milk bio-yoghurt (control) linked to fat, ash and lactose content levels in cows milk.
3- Increasing the goat milk ratio in the mixture caused fat and ash percentages upward while lactose percentages downward until get to the highest fat and ash values and the lowest lactose value in case of goats milk bio-yoghurt (control) linked to fat, ash and lactose content levels in goats milk it could be reported that fat, ash and lactose content of the functional bio-yoghurt containing different levels of goats milk as cows milk substitute were originally affected by the formula contents of fat, ash and lactose in the production process.
4- The functional bio-yoghurt containing different levels of goats milk as cows milk substitute exhibited no significant differences along all functional bio-yoghurt formulations (with mixing cows and goats milk) compared of control samples (pure cows and goats milk bio-yoghurt) in total solids and protein content.
5- The data revealed that functional cows milk bio-yoghurt (control) had lowest total solids value and highest protein value while functional goats milk bio-yoghurt (control) had highest total solids value and lowest protein value among all treatments.
6- Add goats milk with cows milk in functional bio-yoghurt containing different levels of goats milk as cows milk substitute had no significant effect on acidity percentage.
7- The data revealed the functional bio-yoghurt treatment prepared using goat and cow milk in a combined ratio 25:75 had highest titratable acidity among all treatments.
8- Functional cows milk bio-yoghurt 0:100 ratio had the highest titratable acidity followed by the functional bio-yoghurt formulations prepared using goat and cow milk in combination ratios 25:75, 50:50 and 75:25 thereafter the functional goats milk bio-yoghurt 100:0 ratio had the lowest titratable acidity which could be explained by the enhancement of the microbial growth and acidity progress of lactic acid bacteria in cows milk than in goats milk, as a result of lower affected water and lactose, percentage of goats milk than of cows milk.
9- The titratable acidity of all the samples were increased during storage period.
10- Mixed the cows with goats milk, in functional bio-yoghurt mix had no significant effect on pH values.
11- The data revealed the functional bio-yoghurt treatment prepared using goat and cow milk in a combined ratio 75:25 had highest pH values among all treatments.
12- Functional goats milk bio-yoghurt (control) had the highest pH value then an increase in pH value while raising the proportion of goat’s milk in the functional bio-yoghurt samples while cows milk bio-yoghurt (control) had the lowest pH value among all treatments this may be due to that the goat’s milk used in the experiment basically higher than cow’s milk in the pH values.
13- The pH value of all the samples were decreased during storage period.
14- The differences were not statistically significant in syneresis of functional bio-yoghurt containing different levels of goats milk as cows milk substitute compared of control functional bio-yoghurt treatments.
15- Functional cows milk bio-yoghurt (control) had the highest susceptibility to syneresis values followed by the functional bio-yoghurt formulations prepared using goat and cow milk in combination ratios 25:75, 50:50, and 75:25 thereafter the functional goats milk bio-yoghurt (control) had the lowest susceptibility to syneresis values may be due to that determined of syneresis value by means of drainage method varied according to the milk type used for bio-yoghurt manufacture, therefore an increase in the proportion of goat’s milk in the formulations leads to a rise in its pH value, which is followed by a decrease in the syneresis rate.
16- The susceptibility to syneresis values slightly increased in all treatments as the refrigerated storage period progressed up to 14 days.
17- Mixing the goats milk with cows milk in the functional bio-yoghurt containing different levels of goats milk as cows milk substitute had a significant effect on the probiotic bacteria growth.
18- Functional goats milk bio-yoghurt (control) was the lowest ABT-5 bacteria, while Functional cows milk bio-yoghurt (control) was the highest probiotic bacteria, among all treatments.
19- Number of probiotic bacteria gradually decreased along the storage period reaching the minimum counts at the end of storage period.
20- The results indicated that Yeasts & Moulds counts increased progressively during storage.
21- Coliform bacteria were not detected in all functional samples either when fresher and during refrigerated storage.
22- Sensory evaluation results showed that there were significant differences among all functional bio-yoghurt samples except for appearance score.
23- Total scores were slightly decreased during the storage period.
24- The data revealed the functional cows milk bio-yoghurt treatments had highest total score among all treatments followed by functional bio-yoghurt formulations prepared using goat and cow milk in combination ratios 25:75 treatment.
25- from this study, utilizing of goats milk by blending with cows milk up to a ratio of 1:1 could be used by the industrial sector for economic and technological advantages in production of accepted functional bio-yoghurt.
Part III: Production and properties of flavored functional bio-yoghurt drinks containing goats milk and fortified with different types of fruit pulp.
This part of the study was planned to produce a valued product such as a functional bio-yoghurt drinks from goats milk at 50% ratio, with probiotic starter culture (ABT-5) and its flavoring with some types of fruit bulb (blueberry or guava) at 10% ratio, some chemical, functional, microbiological, rheological and sensory properties of different functional bio-yoghurt drinks samples were determined to investigate the impact of these fortified ingredients on the properties of the product. The data obtained and recommended results can be summarized as follows:
1- Some physiochemical composition of blueberry pulp exhibited significant higher total solid, ash, total phenols and antioxidant activity than guava pulp while, no significant difference were observed in fat, protein, titratable acidity content and pH value.
2- Flavored functional bio-yoghurt drinks containing goats milk and fortified with different types of fruit pulp exhibited non-significant total solids content than the same of control treatment.
3- The data revealed the blueberry bulb treatments had highest total solids contents among all treatments.
4- There were no significant differences in fat, protein and lactose contents between control drinking yoghurt and other treatments.
5- Flavored functional bio-yoghurt drinks containing goats milk and fortified with different types of fruit pulp significant differences of ash content than that of control treatments (without fruit pulp).
6- The data revealed the guava bulb treatment had highest ash contents among all treatments.
7- Goats milk functional bio-yoghurt drink without fruits pulp (control) had the lowest titratable acidity among all treatments and cows milk functional bio-yoghurt drinks without fruits pulp (control) were had the highest titratable acidity.
8- The data revealed the guava treatment had higher titratable acidity than blueberry treatment.
9- The titratable acidity of all the samples were increased during storage period.
10- Goats milk functional bio-yoghurt drink without fortified ingredients (control) had the highest pH value among all treatments and cows milk functional bio-yoghurt drinks without fortified ingredients (control) were had the lowest pH value.
11- The blueberry treatment had higher pH value than guava treatment.
12- Addition of different types of fruit pulp in to goats milk functional bio-yoghurt drinks had no significant effect on pH value.
13- The pH value of all the samples were decreased during storage period.
14- Goats milk functional bio-yoghurt drinks fortified with different fruits bulb exhibited significant higher antioxidants content than the same of control treatments without fortified ingredients.
15- The data revealed the blueberry treatments had higher antioxidants content than guava treatment.
16- Goats milk functional bio-yoghurt drink without fruits pulp (control) had higher antioxidants content than cows milk functional bio-yoghurt drink without fortified ingredients (control).
17- Goats milk functional bio-yoghurt drinks fortified with different fruits bulb exhibited significant higher total phenols content than the same of control treatments without fortified ingredients.
18- The data revealed the blueberry treatments had higher total phenols than guava treatment.
19- Goats milk functional bio-yoghurt drink without fruits pulp (control) had higher total phenols than cows milk functional bio-yoghurt drink without fortified ingredients (control)
20- Goats milk functional bio-yoghurt drinks fortified with different fruits bulb exhibited significant higher viscosity value than of control (without fruits pulp).
21- The data revealed the guava treatment had higher viscosity value than blueberry treatment.
22- Cows milk functional bio-yoghurt drink without fruits pulp (control) had higher viscosity value than goats milk functional bio-yoghurt drink without fortified ingredients (control).
23- The viscosity value of all the samples were increased during storage period.
24- Addition of different types of fruits pulp had significantly harmful effect on the probiotic bacterial count’s strains.
25- Treatment fortified with guava bulb was the lowest probiotic bacterial counts, while treatment with blueberry bulb was the highest probiotic bacterial counts, among all treatments.
26- The results also revealed that all functional bio-yoghurt drink samples both, with (treatments) and without (controls) fortified with fruits pulp, contained the recommended levels of probiotic bacterial counts (106 -107 log cfu/ml).
27- Number of probiotic bacterial counts gradually decreased along the storage period reaching the minimum counts at the end of storage period.
28- The results indicated that Yeasts & Moulds counts increased progressively during storage.
29- Coliform bacteria were not detected in all drinking yoghurt samples either when fresher and during refrigerated storage.
30- Sensory evaluation results showed that there were significant differences among flavored functional bio-yoghurt drinks containing goats milk and fortified with different types of fruit pulp samples.
31- The sensory scores of all the samples were decreased during storage period.
32- The data revealed the guava bulb treatment had higher total score than blueberry bulb treatment.
33- from this study, it could be concluded that use of a percentage of adding 10% of blueberry bulb in functional fermented goat milk bio-yoghurt could improve the nutritional value of final product. Also, preferable to fortify with 10% of guava bulb to give the product a desirable flavor.