نقش سفیده تخم مرغ و افزایش ph در مدت زمان ماندگاری و ویسکوزیته نوشیدنی شیر شکلاتی

اﻣﺮوزه ﻣﺤﺼﻮﻻت ﻣﺘﻨﻮﻋﯽ از ﺷﯿﺮ، ﻣﺎﻧﻨﺪ ﻧﻮﺷﯿﺪﻧﯽ ﻫﺎی ﻃﻌﻢ دار ﺗﻬﯿﻪ ﻣﯽ ﺷﻮد، زﯾﺮا ﺑﺴﯿﺎری از اﻓﺮاد ﺑﻪ ﺧﺼﻮص ﮐﻮدﮐﺎن ﺗﻤﺎﯾﻠﯽ ﺑﻪ ﻣﺼﺮف ﺷﯿﺮ ﺑﺪون ﻃﻌﻢ و ﺳﺎده ﻧﺪارﻧﺪ. از ﺳﻮﯾﯽ دﯾﮕﺮ، ﺗﺨﻢ ﻣﺮغ در ﺟﺎﯾﮕﺎه ﺑﺎﻻﺗﺮی ﻧﺴﺒﺖ ﺑﻪ ﺳﺎﯾﺮ ﻣﻨﺎﺑﻊ ﭘﺮوﺗﺌﯿﻨﯽ ﻗﺮار دارد ﮐﻪ ﺑﻪ اﻏﻠﺐ ﻣﺤﺼﻮﻻت ﻏﺬاﯾﯽ اﻓﺰوده ﻣﯽ ﺷﻮد ﺗﺎ ارزش ﺗﻐﺬﯾﻪ ای را اﻓﺰاﯾﺶ و ﻫﻤﭽﻨﯿﻦ ﺧﻮاص ﻋﻤﻠﮑﺮدی را ﺑﻬﺒﻮد ﺑﺨﺸﺪ. ﺑﻨﺎﺑﺮاﯾﻦ در اﯾﻦ ﺗﺤﻘﯿﻖ از ﭘﺮوﺗﺌﯿﻦ ﺳﻔﯿﺪه ﺗﺨﻢ ﻣﺮغ و ﺷﯿﺮ ﺷﮑﻼﺗﯽ ﺑﺮای ﺳﺎﺧﺖ ﻧﻮﺷﯿﺪﻧﯽ ﭘﺮوﺗﺌﯿﻨﯽ اﺳﺘﻔﺎده ﺷﺪ. ﺑﺎر ﻣﯿﮑﺮوﺑﯽ و ﺗﻐﯿﯿﺮات ph، ﻃﯽ 10 روز ذﺧﯿﺮه ﺳﺎزی در ﯾﺨﭽﺎل، ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮارﮔﺮﻓﺖ. ﻋﻠﯿﺮﻏﻢ ﺑﺎﻻ ﺑﻮدن ﺗﻌﺪاد ﮐﻞ ﺑﺎﮐﺘﺮﯾﻬﺎ در ﻧﻤﻮﻧﻪ ﻫﺎی ﺣﺎوی ﺳﻔﯿﺪه ﺗﺨﻢ ﻣﺮغ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻧﻤﻮﻧﻪ ﻫﺎی ﺷﺎﻫﺪ در روز اول، در ﻃﯽ زﻣﺎن ذﺧﯿﺮه ﺳﺎزی، رﺷﺪ در ﻧﻤﻮﻧﻪ ﻫﺎی ﺷﺎﻫﺪ ﻓﺎﻗﺪ ﺗﺨﻢ ﻣﺮغ ﺑﺴﯿﺎر ﺳﺮﯾﻊ ﺗﺮ ﺑﻮد، ﺑﻨﺎﺑﺮاﯾﻦ در روز ﭘﻨﺠﻢ، ﻧﺮخ رﺷﺪ در ﻧﻤﻮﻧﻪ ﻫﺎی ﺷﺎﻫﺪ 2 ﭼﺮﺧﻪ ﻟﮕﺎرﯾﺘﻤﯽ و در ﻧﻤﻮﻧﻪ ﻫﺎی ﺗﺤﺖ درﻣﺎن(0/2 ﺗﺎ 1) ﭼﺮﺧﻪ ﻟﮕﺎرﯾﺘﻤﯽ اﻓﺰاﯾﺶ ﯾﺎﻓﺖ. ﮐﻪ ﻧﺸﺎن داد ﺑﺎ اﻓﺰاﯾﺶ درﺻﺪ ﺳﻔﯿﺪه ﺗﺨﻢ ﻣﺮغ، ﺗﻌﺪاد ﺑﺎﮐﺘﺮی ﻫﺎ ﺑﻪ ﻃﻮر ﻗﺎﺑﻞ ﺗﻮﺟﻬﯽ ﮐﺎﻫﺶ ﯾﺎﻓﺖ. در روز ﻫﻔﺘﻢ، ﺗﻌﺪاد ﮐﻞ ﺑﺎﮐﺘﺮی ﻫﺎ ﻣﺰوﻓﯿﻞ ﻫﻮازی ﺑﯿﻦ 3/55 ﺗﺎ 4/06 (log10 cfu/ ml) ﺑﻮد ﮐﻪ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻣﯿﺰان اﺳﺘﺎﻧﺪارد ﺷﯿﺮ ﭘﺎﺳﺘﻮرﯾﺰه ﺑﻬﺘﺮﯾﻦ زﻣﺎن ذﺧﯿﺮه ﺳﺎزی ﻫﻔﺖ روز ﺑﻮد. ﻫﻤﭽﻨﯿﻦ ﮐﻠﯿﻔﺮم، اﺷﺮﺷﯿﺎﮐﻠﯽ، ﺳﺎﻟﻤﻮﻧﻼ و ﮐﭙﮏ و ﻣﺨﻤﺮ ﻣﺸﺎﻫﺪه ﻧﺸﺪ. از ﺳﻮﯾﯽ دﯾﮕﺮ، اﻓﺰودن ﺳﻔﯿﺪه ﺗﺨﻢ ﻣﺮغ ﺑﺎﻋﺚ اﻓﺰاﯾﺶ ﺳﻄﺢ ph ﺑﻪ 8/7-8/3 ﺷﺪه و ﻣﻮﺟﺐ ﮐﺎﻫﺶ ﻓﺴﺎد اﺳﯿﺪی ﮔﺮدﯾﺪ. ﻫﻤﭽﻨﯿﻦ راﺑﻄﻪ ﻣﺴﺘﻘﯿﻤﯽ ﺑﯿﻦ اﻓﺰاﯾﺶ درﺻﺪ ﺳﻔﯿﺪه ﺗﺨﻢ ﻣﺮغ ﺑﺎ اﻓﺰاﯾﺶ وﯾﺴﮑﻮزﯾﺘﻪ وﺟﻮد داﺷﺖ، اﻣﺎ وﯾﺴﮑﻮزﯾﺘﻪ ﻧﻤﻮﻧﻪ ﻫﺎی ﺑﺎ درﺻﺪ ﺳﻔﯿﺪه ﺑﺎﻻﺗﺮ در ﻃﻮل دوره ﻧﮕﻬﺪاری ﮐﺎﻫﺶ ﯾﺎﻓﺖ.

The Effect of Adding Eggwhites and Increasing pH on Shelf Life and Viscosity of Chocolate Milk Drinks

Today, a variety of milkbased products are made with flavored beverages, because many people, especially children, are reluctant to consume unpasteurized milk. On the other hand, eggs are placed in higher degree than other sources of protein nutritionally, that they are added to most food products to increase their nutritional value as well as improve their functional properties. Therefore, in this study, Egg white protein and chocolate milk were used for making protein beverage. Microbiological count, sensory attributes and pH changes were investigated during 10 days of refrigerated storage. At the tenth day, the total numbers of bacteria were between 4.05 5.77 (Log10 CFU/ml). It was concluded that when egg white amount increased, the number of bacteria significantly decreased. No coliforms, Ecoli, salmonella, mold and yeast were observed. Also, pH levels increased to 8.38.7 and reduced acidic spoilage. Also, there was a direct relationship between increasing egg white amount and decreasing the amount of cocoa and sugar in increasing the viscosity and the viscosity values ​​of the samples with higher egg white content decreased during storage time and samples with lower percentages of egg white increased.