Study On The Technology-product Quality Improvement Of Composite Powder Made From Wheat Germ And Low-cost Fish

The objective of this research was to prepare a nutrition powder of soluble and solid which is produced from wheat germ and low-value fish via extruding technology(by DS32 Twin-Screw Extruder under different condition of processes), grinding, allocation. The aim of this product is to develop a new convenience nutritional food, giving consideration to the economic, nutrient, low value-added and high-quality processing techniques.Firstly, in order to get a proper moisture content of pretreatment material, the effects of hot air drying, vacuum drying and microwave drying on pretreatment material's colour, Av and POV were tested. Choosing microwave drying as the drying model and the Page mathematics model is obtained as follow: MR= exp[ -e(-4.469+0.745P-0.0503P2)t(2.205-0.345P+0.0376P2)].Secondly, four sorts of starchs were compared, then we found potato starch was suitable. The combination of regression and response surface analysis were introduced in the optimization of the extrusion technology. The results showed as follows: potato starch dosage(X1)=33.3%, extrusion temperature(X2)=163℃,moisture content(X3)=18.7%, and scr- ew speed(X4)=160 R/min. A good degree of expansion and uniform fine cellular structure was got under these conditions, it was also beneficial to improve late pulverization and the stability of soluble.Thirdly, optimal granular size at 120～150μm was got by powder's fluidity and stability experiment. Through sensory evaluation experiment, optimal formula with white sugar,salt and wheat aroma at the ratio of 1.5%:2.4%:0.1% was obtained.Finally, fitting moisture content in storing at 4.8% were obtained from Aw's test and change. By POV's first-order kinetics prediction, composite nutrition powder's shelf life predictor formula was as follow:Lnts=-0.063Ts+6.59, sensory evaluation and change of microorganimn- im of storage experiment was got to national safe standard.