| As a traditional Chinese food,Zongzi is deeply favored by consumers because of its unique quality.However,at present,Zongzi is mostly based on glutinous rice,which is consisted of single nutrient and not easy to digest,putting large burden on the stomach.Besides,it can't be cooked together with other ingredients,which is time-consuming and with huge energy consumption.In this paper,corn,buckwheat,glutinous rice,glutinous rice and red beans were used as ingredients.The optimal formula of the grains were determined according to the balanced nutritional dietary demand,and the amino acid composition was close to the reasonable dietary standard model proposed by FAO/WHO.The Tremella powder was added based on this,and the optimum amount of Tremella powder was determined by studying the rheological properties and gelatinization properties of the mixed powder.The Tremella-multigrain granules were prepared by extrusion technology.On the basis of single factor,the optimum cooking conditions of Tremella-multigrain Zongzi were optimized by response surface test design.Finally,the shelf life of Tremella-multigrain Zongzi was predicted by the change of total number of colonies,water content,color,texture and sensory score.Tremella-multigrain Zongzi had a complete shape,sticky taste and strong aroma.It improved the nutritional value of Zongzi under the premise of ensuring the viscoelasticity.At the same time,it also provided reference for the development of edible fungus cereal food for fungi to become edible staple food.1.By measuring the amino acid composition of each raw material and using the EAAI(essential amino acid index)value of the grain powder as an index,the best formula for the grain was determined as follows: the amount of corn flour added 7%,buckwheat flour 9%,red bean powder 11%,myotonin powder 12%,and the amount of glutinous rice flour added was 61%.2.On fixed multigrain powder formula,the effects of various amount of Tremella powder on the dynamic rheological properties,dynamic time rheological properties and gelatinization properties of the multigrain powder were studied.It was concluded that: both G' and G" in dynamic rheology and dynamic time rheology were increased with the increasing of Tremella powder.The peak viscosity,the valley viscosity,the final viscosity and the retrogradation value increased with the increasing of Tremella powder.When the amount of Tremella powder was 8%~12%,the rheological properties and gelatinization characteristics of the Tremella-multigrain powder were better than that of glutinous rice.The optimum addition amount of the Tremella powder was determined by the texture characteristics of the Tremella grain granules to be 10%.3.On the basis of single factor test,the extrusion process of the Tremella-multigrain granules optimized by the Design Expert 8.0.6 software was as follows: the water addition was 34.74%,the initial extrusion temperature was 157.49 °C,and the second extrusion temperature was 139.55 °C.Considering the actual operability,the process conditions were adjusted to 36% water addition,160 °C for initial extrusion,and 140 °C for second extrusion.The Tremella-multigrain granules prepared under these conditions contained fat(0.49±0.06)%,protein(9.26±0.04)%,starch(91.03±0.79),amylose(14.61±1.20)%,and cooking loss rate(4.00±0.15)%,water absorption(201.00±9.00)%,and expansion ratio(395.81±7.30)%.In terms of texture characteristics,the hardness of Tremella-multigrain granules was(246.30±16.81)g,viscosity was(-268.04±1.49)g,springiness was(9.51±0.74)%,chewiness was(2712.31±9.95)g.sec.Tremella-multigrain granules were slightly different from the two commercially available glutinous rice.4.Based on the single factor test,the optimal cooking process for the Tremella-multigrain Zongzi was optimized by Design Expert 8.0.6 software: the soaking time of the Tremella-multigrain granules was 30 min,the cooking time of the Tremella-multigrain Zongzi was 7.5 min,and the sterilization time was 20 min.The texture characteristics of Tremella-multigrain Zongzi prepared under such conditions were: hardness(655.69±30.25)g,viscosity(-294.17±6.60)g,springiness(25.54±0.33)%,and chewiness(4326.66±90.03)g.sec.5.At room temperature(20 ?),measure for the shelf life,ten days later,the total number of bacterial colonies of Tremella-multigrain Zongzi exceeded the national sales standards.The water content decreased with the increasing of storage time,and the decline rate slowed down after 4 days.As for the change of color,the Tremella-multigrain Zongzi changed from light yellow to dark brown.;According to the trend of texture change,the Tremella-multigrain Zongzi had good texture characteristics in the first 8 days of storage period.Finally,the change of comprehensive sensory score showed that Tremella-multigrain Zongzi still had good edible quality within 8 days of storage time. |
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