| Fresh hot and dry noodles(FN)are a popular breakfast food and a postcard of Wuhan cuisine culture.FN is processed by dough mixing,curing,composite calendering,strip cutting,cooking and oil mixing.Compared with dried noodles such as hung noodles,more fresh,refreshing,chewy,taste better,and can be cooked in a variety of ways,then it is thought to be an ideal food in the fast-paced life of the day.However,the content and activity of water in FN are high,and it is easy to browning,aging and breaking during storage,which makes its edible quality lower.In addition,FN is easily infected by bacteria,mold which results in spoilage.Therefore,the preservation of FN is an important problem to limit its large-scale production.In view of this,this article introduced edible fungus fermentation liquor to inhibit spoilage microorganism and improved the processing technology of FN by means of compound preservation.The main research contents and results are as follows:(1)In order to determine the main spoilage microorganisms in the FN,the strains isolated from the noodles was identified by 16 S r DNA fragment sequence and biochemical analysis.As a result,one strain of Bacillus cereus was identified.Further,in order to screen the fermentation products of edible fungi with inhibitory effect on the bacterium,26 strains from 5 species were analyzed in this study.Then taking the rate of mycelial growth as the screening index,one strain respectively from of Lentinula edodes,Tremella sanguinea,Auricularia auricula-judae,Hericium erinaceus and Cordyceps militaries was selected to conduct the submerged fermentation.Subsequently,to screen the optimum strain for inhibiting the growth of B.cereus,the inhibitory effect of fermentation products on the growth of B.cereus was evaluated.Finally,the inhibition effects of fermentation broth on Escherichia coli,Bacillus subtilis,Staphylococcus aureus were evaluated.In addition,the fermentation broth of Macheng had good bacteriostatic effects on E.coli and B.subtilis,S.aureus.The results of this study provide a reference for the application of the fermentation broth in the production and preservation of FN.(2)The formulation of FN was optimized.Firstly,the single factor experiment was used to determine the optimal range of edible alkali,fermentation broth,salt and gluten by comparing the texture of noodles,cooking characteristics and sensory evaluation.Then orthogonal experiments were carried out on the basis of the results of the single factor experiment,and then according to the results of orthogonal experiment,the influence factors on noodle quality were: edible alkali > fermentation broth > salt > gluten.The optimal combination for FN was edible alkali 0.6 g,34 m L of fermentation broth,salt 1 g and 4 g of gluten.Subsequently,the optimal formulation was determined to be the optimal combination by validation experiments,and the sensory evaluation score was 86.67±0.58.In addition,after optimization,the palatability,toughness and taste of the noodles were greatly improved after optimization,and the quality of the noodles was also greatly improved.(3)According to the test,the shelf life of FN containing edible mushroom fermentation broth was 4 d at 4?,which was longer 2 d than the ones without edible mushroom fermentation liquid.To prolong the shelf life,the ?-60 Co irradiation was conduct,and the irradiation dose was determined to be 4 k Gy based on the quality of the noodles and the inhibitory effect on microorganisms.At this dose,the shelf life of FN containing edible mushroom fermentation broth was extended to 8 d at 4?,which was 4 days longer than that of unirradiated ones at 4?.However,a small amount of mold remained in the noodles although the bacteria were largely suppressed after irradiation,Therefore,calcium propionate was introduced into the noodles to inhibit the mold,and as a result,the shelf life of the FN extended to 12.8d after the composite preservation treatment. |
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