پديد آورندگان :
كشاني، مريم دانشگاه آزاد اسلامي واحد اصفهان (خوراسگان) - دانشكده كشاورزي - گروه علوم و صنايع غذايي , نفيسه، زميندار دانشگاه آزاد اسلامي واحد اصفهان (خوراسگان) - دانشكده كشاورزي - گروه علوم و صنايع غذايي , حاجيان، رضا دانشگاه صنعتي اميركبير - دانشكده مهندسي پزشكي - گروه بيوالكتريك
كليدواژه :
ماهي تن , انجمادزدايي , اهميك , ازت فرار , حلاليت پروتئين
چكيده فارسي :
از ﻧﮑﺎت ﻣﻬﻢ در ﻓﺮاﯾﻨﺪ ﻣﻮاد ﻏﺬاﯾﯽ ﻣﻨﺠﻤﺪ، اﻧﺠﻤﺎدزداﯾﯽ ﺑﺎ ﺣﺪاﻗﻞ آﺳﯿﺐ ﺑﻪ وﯾﮋﮔﯽﻫﺎي ﮐﯿﻔﯽ آن اﺳﺖ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﯾﻨﮑﻪ روشﻫﺎي ﻣﻌﻤﻮل ﻣﻮرد اﺳﺘﻔﺎده ﺑﺮاي رﻓﻊ اﻧﺠﻤﺎد ﻣﻮادﻏﺬاﯾﯽ ﺳﺮﻋﺖ ﮐﻤﯽ داﺷﺘﻪ و ﺑﺎﻋﺚ ﮐﺎﻫﺶ ﮐﯿﻔﯿﺖ ﻣﺤﺼﻮل ﻣﯽﺷﻮﻧﺪ، اﺳﺘﻔﺎده از روشﻫﺎي اﻧﺠﻤﺎدزداﯾﯽ ﮐﺎرآﻣﺪ ﺿﺮوري ﺑﻪﻧﻈﺮ ﻣﯽرﺳﺪ. اﻧﺠﻤﺎدزداﯾﯽ اﻫﻤﯿﮏ ﯾﮏ روش ﺣﺮارﺗﯽ- اﻟﮑﺘﺮﯾﮑﯽ ﺑﺎ ﺗﻮاﻧﺎﯾﯽ ﺗﻮﻟﯿﺪ ﮔﺮﻣﺎي ﯾﮑﻨﻮاﺧﺖﺗﺮ ﻧﺴﺒﺖ ﺑﻪ دﯾﮕﺮ روشﻫﺎي اﻧﺠﻤﺎدزداﯾﯽ ﻣﯽﺑﺎﺷﺪ. در اﯾﻦ روش ﺑﺎ ﺗﻌﯿﯿﻦ ﻣﯿﺰان ﺟﺮﯾﺎن اﻟﮑﺘﺮﯾﮑﯽ ﮔﺬرا از ﻣﺤﺼﻮل ﻣﯽﺗﻮان ﺳﺮﻋﺖ اﻧﺠﻤﺎدزداﯾﯽ را ﺗﻐﯿﯿﺮ داد. در اﯾﻦ ﭘﮋوﻫﺶ ﺗﺎﺛﯿﺮ اﻧﺠﻤﺎدزداﯾﯽ ﻣﮑﻌﺐﻫﺎي ﻣﻨﺠﻤﺪ ﻣﺎﻫﯽ ﺗﻦ ﺑﺎ روش اﻫﻤﯿﮏ ﺑﻪﺻﻮرت ﻏﻮﻃﻪوري در وﻟﺘﺎژ 50، ﻓﺮﮐﺎﻧﺲ ﺛﺎﺑﺖ 50 ﻫﺮﺗﺰ و در ﺳﻪ ﻏﻠﻈﺖ ﻣﺨﺘﻠﻒ آب ﻧﻤﮏ )0/3، 0/4، 0/5درﺻﺪ( ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ و ﺧﻮاص ﺷﯿﻤﯿﺎﯾﯽ و ﻓﯿﺰﯾﮑﯽ ﻧﻤﻮﻧﻪﻫﺎ ﻃﯽ ﺳﻪ روز ﻧﮕﻬﺪاري در دﻣﺎي 4 درﺟﻪ ﺳﺎﻧﺘﯽﮔﺮاد ﺑﻌﺪ از اﻧﺠﻤﺎدزداﯾﯽ اﻧﺪازهﮔﯿﺮي ﺷﺪ. ﻣﻄﺎﺑﻖ ﺑﺎ ﻧﺘﺎﯾﺞ آزﻣﻮن ﺗﺠﺰﯾﻪ وارﯾﺎﻧﺲ ﻃﺮح ﮐﺎﻣﻼ ﺗﺼﺎدﻓﯽ، ﮔﺬﺷﺖ زﻣﺎن ﺑﺎﻋﺚ اﻓﺰاﯾﺶ ﺣﻼﻟﯿﺖ ﭘﺮوﺗﺌﯿﻦ، pH، ﮐﻞ ﻧﯿﺘﺮوژن ﻓﺮار ﺑﺎﻧﺪ ﺷﺪه، ﮐﺎﻫﺶ اﻓﺖ ﺳﺎﻧﺘﺮﯾﻔﻮژ و اﻓﺸﺮه داراي اﺳﺎﻧﺲ ﮔﺮدﯾﺪ. اﺛﺮ ﻏﻠﻈﺖ ﺑﺮ ﺳﺮﻋﺖ رﻓﻊ اﻧﺠﻤﺎد ﻣﻌﻨﯽدار ﻧﺒﻮد وﻟﯽ ﺑﺮ اﻓﺖ اﻧﺠﻤﺎدزداﯾﯽ، اﻓﺖ ﺗﺒﺨﯿﺮ، اﻓﺖ ﺳﺎﻧﺘﺮﯾﻔﻮژ، ﺗﻠﻔﺎت ﻋﺼﺎره و ﮐﻞ ﻧﯿﺘﺮوژن ﻓﺮار ﺑﺎﻧﺪ ﺷﺪه در ﺳﻄﺢ اﺣﺘﻤﺎل 5% اﺛﺮ ﻣﻌﻨﯽداري ﻧﺸﺎن داد.
چكيده لاتين :
Introductıon: The Scombridae family of fish consists of tuna, bonito and mackerel species that are found in warm waters. Tuna species is important because of economic value and prevalence in global trade. Although, they are usually not consumed fresh because of the limited fishing season, lack of accessible markets at certain locations and cost of transport to other areas. Therefore, long-term preservation methods must be used. For many years, freezing has been the method of preserving food for a longer period without a significant quality decrease. Thawing with minimal damage to the products quality is very important. Since common thawing methods are usually slow and reduce food quality, a substituted technique seems necessary. Ohmic thawing is a thermal-electrical method with a more uniform heat compared to other thermal-electrical methods. The speed and relative uniformity of ohmic heating is possible by passing direct electrical current through the product. In this process, the electrical resistance of frozen food is utilized. Electrical energy passes through food by means of electrical current and is dissipated in the form of heat (Joule effect). Based on Ohm’s law, the amount of dissipated heat is directly related to the used voltage and the electrical conductivity of the product or its parts.
Materials and Methods: Muscles of the frozen tuna fish were cut into 3x3x3 cm cubes and kept in zip lock bags and stored at -30 for 24 h. Then the samples maintained at -18 until the experiments time. The ohmic cell was filled with saline solution (0.3%, 0.4% and 0.5% respectively) and the thermocouple was connected to the geometric centre of the frozen fish at -18. Then a voltage of 50 volts with 50Hz frequency was applied until the sample centre reached -7. The samples were then removed from the cells and protein solubility, pH, TVBN, centrifuge loss, thawing loss, drip loss, evaporation loss, and press juice were measured at 0, 24 and 48 h after thawing. Completely randomize design in factorial form with three replications was carried out for the experiments. Data were analyzed by SAS software.
Results and Discussion: In this research, ohmic thawing was evaluated as a new method for thawing fish. According to the results of ANOVA, with passing of time the protein solubility, pH, TVBN, centrifuge loss and press juice was increased. With further study of ANOVA of thawing loss and drip loss, it was concluded that salt concentration had a significant effect on dependent parameters (P<0.05). While keeping a high thawing speed, no burning marks appeared on the edges and around the samples in the ohmic method.
