The Research On Process Technology And Anti-staling Of Fermented Potato-rice Cake

The fermented rice cake is a traditional Chinese fermented rice food,which has a soft and flurry structure with a high quality of flavor and taste.People can easily digest and absorb the nutrients of it.So,the fermented rice cake is very popular around the people.Potato is one of the four staple crops in the world,which is rich in nutrition and consumed worldwide.In China,potato is usually cooked as dishes,which has greatly reduced its available value.In June 2015,the Ministry of Agriculture put forward the strategy of staple crop for potato,which encourage people to combine the potato flour with the other staple crops to explore the special staple foods of potato.This thesis studied the physic-chemical properties of the potato-rice flour by adding potato flour into the rice flour.On the basis of the physic-chemical properties,the process technology and formula of fermented potato-rice cake were studied and then optimized.At the end of the study,it selected the anti-stale additive that could effectively reduce the stale degree of the fermented potato-rice cake.The results were showed as follows:(1)The regular variation pattern that solubility,swelling power,adhesive strength,pasting and gel textural properties of the potato and rice flour and their blends were studied.The results showed that at different temperatures,the solubility and swelling power of the mixed flour were increased as increasing the addition of potato flour and it revealed a very significant positive correlation between the potato flour's addition and the solubility and swelling power.The adhesive strength was increased as the potato flour's addition was increased.On the other hand,the pasting properties showed a reducing trend when increasing the potato flour's addition in the potato-rice system and there was a very significant negative correlation between the two factors.The gel textural properties also showed a reducing trend when increasing the potato flour's addition and among the parameters of the gel textural properties,the hardness,gumminess and chewiness had a negative correlation with the potato flour's addition.(2)Using consulting investigation and expert survey method to establish the sensory evaluation system of fermented potato-rice cake.The results showed that taste was 20 points and flavor was 15 points,then the moisture content,hardness,springiness,chewiness,color,internal flesh structure were both 10 points and finally the gumminess was 5 points.On the premise that guarantee the quality of the fermented potato-rice cake,the addition of potato flour increased to 35%.Optimizing the process technology and the formula,then acquired the final parameters that is rice32.5g,potato flour 17.5g,yeast 0.875g,sugar 13.2g,fermentation temperature 32?,fermentation time 6h,steaming time 20min.Under this condition,the fermented potato-rice cake had a high sensory quality and good textural properties.(3)Through single factor experiment and Box-Behnken Design method,different anti-stale additives were studied to reduce the stale degree of the fermented potato-rice cake which had stored at 4?for 5d.The results showed that both?-amylase,?-cyclodextrin and sodium alginate could effectively reduce the hardness of fermented potato-rice cake.When the addition amount of?-amylase is 0.004%,?-cyclodextrin 0.15%and sodium alginate 0.06%,the anti-stale effect of corresponding additives were best.Using the Box-Behnken Design method for the three anti-stale additive,a hardness model for the fermented potato-rice cake which had stored at 4?for 5d was established.The equation was as follows:Y=4780.77-392474A-51855.405B-23009.13C+1348250AB+558425AC+101243BC+21141300A~2+236672B~2+45059.74C~2.Through the variance analysis of the model and the different anti-stale additives,acquired that the model was very significant and both all the three anti-stale additives had a significant effect on the hardness of fermented potato-rice cake which had stored at 4?for 5d.The excellent formula that obtained from the equation is?-amylase 0.0053%,sodium alginate 0.0617%,?-cyclodextrin 0.1532%.Verification test proved that the hardness of fermented potato-rice cake was 369.76g,which was closed to the predictive value 379.89g.This greatly proved that the hardness model was effective and feasible.