اثر پيش سرد كردن و زمان نگهداري بر كيفيت خمير سنگك: اندازه گيري و مدلسازي

چكيده انگليسي :

Effect of pre cooling and storage time on the quality of frozen Sangak dough measurement and modeling Abstract Bread is a staple food in many countries due to its nutritional sensorial and textural characteristics Fresh bread has a short shelf life and by considering this matter its acceptability by consumer dramatically would reduce by increasing the time between baking and consumption Frozen dough technology by keeping the technological and time consuming operation at the industrial level makes possible to access fresh bread with a minimum of 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 in the 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 storage cold pre treatment and pre fermentation in sangak frozen dough and its bread was considered in order to improve its freezing process Toward investigation of pre fermentation dough was prepared in three form of non fermented pre fermented and formed pre fermented and non formed Time of pre fermentation was 30 min in order to investigated of cod pre treatment dough placed in a climatic chamber at 4 C until temperature of dough reaching 4 C another sample after reaching to 4 C holding 1 hour in this temperature standard dough frozen non cooled Then dough frozenunder 25 C in air blast freezer After freezing the dough pieces were stored at 18 C for 24 hours 4 7 10 and 13 weeks Samples were removed from the freezer at the specified time Thawed dough was proofed for 90 or 120 min to obtain 120 min at a total fermentation time and then fermented dough was baked Sangak frozen dough quality was assessed by measuring yeast survival gassing power dough expansion after thawing and weight loss of frozen dough duration of storage Characteristics of frozen dough bread were evaluated by measuring density texture and color analyzing after baking and investigated bread staling duration 72 hours after baking Results showed viability of yeast decreased by freezing and longer storage time increased decay in yeast population Pre cold treatment make retention rather survival yeast percentage although pre fermentation reduce viability of yeast A correlation was observed between gassing power dough expansion and yeast viability Further increase in weight loss of frozen dough was observed whit prolong storage time Pre cold treatment and non fermented dough had a lowest weight loss of frozen dough Results obtained from investigation the characteristics of sangak frozen dough bread showed density and firmness of bread increased and crust lightness decreased whit increase in storage time Pre cold treatment decrease density crumb and crust firmness and crust lightness Bread obtained of non fermented dough had a lowest density crumb and crust firmness and lightest crust Investigation of bread staling duration 72 hours after baking showed shear stress and center force were increased duration 72 hours after baking Comparing of rate constant obtained of shear stress and center force variations against time showed that prolong of storage time increased rate of bread staling Keywords frozen dough pre fermentation pre cold treatment frozen storage Sangak bread PDF created with pdfFactory trial version www pdffactory com

فلاح جوشقاني، سعيده

اثر پيش سرد كردن و زمان نگهداري بر كيفيت خمير سنگك: اندازه گيري و مدلسازي

خمير منجمد , پيش خمير , مدت زمان نگهداري و نان سنگك