Study On The Myofibrillar Character And Processing Of Illex Argentinus Castellanos

Illex argentinus is rich in resource, whose annual output reaches10thousand tons in ourcountry. It’s rich in nutrition also, which contains several kinds of essential amino acids. Theessential amino acid compositions are significantly similar to that of total protein. However, tillnow，with very few methods of deep processing for Illex argentinus, the processing varietieshave lacked diversity. In order to exploit and use Illex argentinus, its chemical components,characteristics of its myofibril protein, the water holding capacity of its myofibril protein,composite aquasorb for preservation, and the processing technology for squid surimi and tooptimize, were studied in this paper, with a view to provide a theoretical basis for industrialproduction.The chemical component of Illex argentinus and the changes of total–SH content of myofibrilprotein and myofibril heavy chains （MHC） under different temperatures were investigated. Theresults showed that: Ratio of meat of Illex argentinus was40.6%.The weight of squid head, tail,visceral, skin and bone were respectively25.9%、8.58%、23.9%、1.01%and0.137%of the bodyweight.Water content, crude protein content, crude fat content, ash content, reducing sugar andtotal sugar of meat were respectively78.3%,18.9%,2.19%,1.40%,0.028%and0.069%. Thecontent of myofibrils in the protein components （68.3%） was the highest. Within24hours, thetotal–SH content of myofibril protein didn’t change with time at4℃. The total–SH contentincreased with time at first, and then reduced at20℃,30℃. At40℃,50℃,60℃,70℃, thetotal–SH content decreased with time, and the higher the temperature, the faster the descendingspeed of total–SH content. No obvious degradation of protein of myosin heavy chain wasobserved at10℃,20℃. The degradation speed of protein of myosin heavy chain increased withtime and temperature in30℃⁵5℃, and the fastest degradation speed was at55℃. However,the degradation speed decreased at60℃and70℃.The effect of NaCl concentration, extract pH, temperature, polyphosphate and water absorbenton water holding capacity of myofibrillar protein gel, and on the basic of above optimumconditions, the effect of NaCl concentration, polyphosphate, composite aquasorb on muscleprotein gel from squid were studied. Applied Experiment of composite aquasorb to whole squidwas studied also, with a view to apply in the preservation of squid. The results showed that: theoptimum NaCl concentration, extract pH, temperature and polyphosphate for myofibrillarprotein gel were0.7mol·L^-1,6.6,70℃,and adjusting the final solution to6.6respectively. Thewater holding capacity of myofibrillar protein gel was enhanced by single water absorbent ofGlycerol, trehalose, lactose, soluble starch, sodium polyphosphate and β-cyclodextrin. The waterholding capacity of myofibrillar protein gel added those single water absorbents was11.2%、10.2%、9.62%、7.61%、7.32%and0.530%higher than the control respectively. The complexformulation of Sodium polyphosphate and glycerol was better in water holding capacity ofmyofibrillar protein gel when mixed the single water absorbents, and its water holding capacitywas35.0%higher than the control. The results showed that added the composite aquasorb,which the volume of glycerol was6.0%in the total volume of NaCl and poly-phosphate solution, increased the weight of squid significantly. The weight gain rate was17.8%, which increased by220%compared with the control.Salt-soluble protein content、whiteness、Gel trait level and gel strength of squid surimi washedby three kinds of washing water were all better than the squid surimi washed by flesh water. TheOptimum Technology conditions of washing combined with above indicators was that washed by0.5%NaHCO₃solution （which was five times volume of squid surimi） for three times, thewhiteness and gel strength of squid surimi was the higher.The time of blending without any addition and blending with salt can affect the gel strength ofsquid surimi.The gel strength increased with time at first and then reduced. The optimum time ofblending without any addition was5min and the optimum time of blending with salt was10min.The effects of heating methods （one step heating and two step heating）on the gel strength ofsquid surimi were studied. The results showed that the better gel strength of surimi gels wasachieved by two step heating, and the gel srength treated by two step heating increased by6.3%compared with one step heating（90℃，30min）.