عنوان :
اثر پيش تخمير و سرعت انجماد بر كيفيت خمير سنگك منجمد
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
علوم و صنايع غذايي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي
صفحه شمار :
دوازده،91ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
ناصر همدمي
استاد مشاور :
علي نصيرپور، صبيحه سليمانيان زاد
توصيفگر ها :
توان توليد گاز , دانسيته نان , زنده ماني مخمر , سفتي بافت و نان سنگك
تاريخ نمايه سازي :
19/1/92
استاد داور :
نفيسه پورجواد، ميلاد فتحي
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Effect of Pre fermentation and Freezing Rate on Frozen Sangak Dough Quality Abstract Bread always has been known as one of the most popular food products due to its superior nutritional sensorial and textural characteristics Fresh bread has a short shelf life and by considering this matter its acceptability by consumer dramatically reduces by increasing the time between baking and consumption One of the ways to solve this problem and increase the shelf life of bread is use of the frozen dough technology Using this technology makes it possible to access a fresh bread with a minimum need for equipment and with minimal skilled personnel at any time In addition to reducing labor costs and saving time bread waste can also be reduced by using this technology Sangak bread as one of the best bread all over world in terms of nutritional value and flavor and aroma characteristics is a good choice for using in frozen dough technology and other new bread making technologies By regarding this that the food quality would reduce due to the stresses created during freezing and thawing in this current study the impact of freezing rate and degree of pre fermentation in sangak frozen dough and its bread was considered in order to improve its freezing process The pre fermentation was between 0 and 120 min and the corresponding secondly or final fermentation was between 120 and 0 min respectively to obtain total fermentation time of 120 min The pre fermentation dough was formed in flat shape with 3 6 and 9 mm thickness and frozen under 20 25 and 30 C in air blast freezer It was followed by 1 day storage at 18 C and then a second fermentation in some case there was no second fermentation and then to finish the fermented dough was baked Sangak frozen dough quality was assessed by measuring yeast survival gassing power and dough expansion after thawing Characteristics of frozen dough bread were evaluated by measuring density texture and color analyzing after baking Results showed that viability of yeast initially increased and then decreased by increasing freezing rate so that at 25 C the most viability was observed This result showed the improvement of freeze tolerance yeast in short pre fermentation although the viability of yeast decreased in a higher degree of pre fermentation So that in 30 min pre fermentation the maximum viability was observed A correlation was observed between gassing power dough expansion and yeast viability With the characteristics investigation of sangak frozen dough bread the lowest bread density and firmness were obtained with the highest freezing rate and with the short pre fermentation time respectively Bread density and firmness were increased by decreasing the freezing rate and increasing pre fermentation time over 30 min The bread crust color was darker with increasing fermentation time so that lowest L in frozen dough bread was observed at 120 min fermentation Keywords Bread density Bread firmness Freezing rate Frozen dough Gassing power Pre fermentation Sangak bread Yeast survival
استاد راهنما :
ناصر همدمي
استاد مشاور :
علي نصيرپور، صبيحه سليمانيان زاد
استاد داور :
نفيسه پورجواد، ميلاد فتحي
