| The bamboo shoots produced at the relatively concentrated season and prolific in remote areas,resulting in a long span of distribution and sales time,which seriously restricts the development of the bamboo shoot industry.The traditional handling method is to carry out the sulfur fumigation on bamboo shoot preservation.This method improve the taste and flavor of bamboo shoots,and make bamboo shoots preserved longer,although,this process make some sulfur left and more security risks appear.Researches showed that the shelf of vegetables could been extended and on the one hand,the flavor of vegetables could been improved with fermentation of lactic acid bacteria.Therefore,this study aims to improve the traditional fermentation model based on the basic principle of “high-acid,low-salt”,the best fermentation and preservation formula selected for industrial production for enterprises.The bamboo shoots are processed intensively to develop ingredients,which providing diversified bamboo shoot intermediate products for downstream food companies to enrich bamboo shoot product categories and expand the bamboo shoot market.The main research contents and conclusions are as follows:(1)The surface pathogenic microorganisms of bamboo shoots could be killed to a certain extent,and the relevant enzyme activities of bamboo shoots that could promote aging and browning treated with blanching.The single-factor experimental results of the blanching of bamboo shoots showed that the color of bamboo shoots gradually turned yellow,the brightness value decreased,and the bamboo shoots gradually became softer,but the overall change rate not so obvious with the increase of the blanching temperature to the blanching temperature was between 80-100℃.The relative residual enzyme activity in bamboo shoots rapidly decreased with the prolonging of blanching time,while the soluble solids content increased first and then decreased.Therefore,from the perspective of energy conservation,in order to passivate the enzyme activity faster and keep the nutrients of bamboo shoots as much as possible,the best process for selecting blanching is: the blanching temperature is 95℃,and the blanching time is 5 min.(2)On the basis of single-factor tests,the salt concentration,sucrose concentration and lactic acid bacteria suspension concentration were the main factors.The crude fiber content and sensory quality in fermented bamboo shoots were used as evaluation indicators.The orthogonal experiment was used to optimize the fermentation conditions of bamboo shoots.Optimum process conditions: salt concentration 4%,sucrose concentration 4%,lactic acid bacteria suspension concentration 5%,fermentation temperature 30 ℃,bamboo shoot preservation up to 60 days or longer,and the nutritional composition,texture characteristics and quality of bamboo shoots under different treatment methods of the fermentation process were compared and analyzed.(3)The contents of main nutrients of bamboo shoots were analyzed and compared in the fermentation process with different treatments to provide theoretical basis for preservation of fresh bamboo shoots in the work.The results showed that the effects of preservation for bamboo shoots were the best by the treatment of blanching and fermentation compared with the other three ones.After 63 d of fermentation,the protein,soluble sugar and cellulose in the bamboo shoots were 0.36/100(g/g),0.13%,8.87% and respectively.The contents of potassium and calcium increased of 458.48mg/kg and 50.53mg/kg while the losses of iron and magnesium etc decreased the least.Compared with the other three methods,the treatment of blanching and fermentation could keep the contents of soluble sugar and protein of bamboo shoots better,reduce the rate of lignification and accelerate the element transfer between the bamboo shoot and the broth which was beneficial to increase the contents of elements in the bamboo shoots.These results indicated that the edible quality of bamboo shoots could be kept most effectively while the bamboo shoots could be kept longer by this method.The results showed that textural characteristics such as hardness,and fracturability decreased obviously after 63 d treatments.Compared with other methods,the loss of textural characteristics such as hardness,and fracturability cohesiveness of bamboo shoots treated by the process of fermenting by lactic acid bacteria after blanching were relatively low.After 63 d treatments,the scanning electron microscope images of bamboo shoots revealed that the parenchyma cells were obviously shrunk while the cell gap increased.The cell structure ofbamboo remained relatively complete with the process of fermenting by lactic acid bacteria after blanching.In addition,compared to that of fresh bamboo shoots,the color was significantly changed(the total color diference ΔE>2)after 63 d treatments.Comprehensive evaluation found that the edible quality and the color of bamboo shoots could be maintained effectively with the process of fermenting by lactic acid bacteria after blanching.It was found that titratable acidity concentration was increased and a peak of nitrite appeared during fermenting,p H declined,and total volatile flavour compounds increased.Beyond that,total acid content was 5.39 g/kg,nitrite content in the minimum of 0.45 mg/Kg,and there were 65 species volatile compounds in bamboo shoots after 63 d with fermenting.Therefore,the quality of the fermented food were improved effectively and the effects of preservation for bamboo shoots were the best by the treatment of blanching and fermentation.(4)The best technology for water bamboo shoots is to fully rinsing the fermented bamboo shoots obtained in the previous period in running water.The rinsing time can be properly adjusted according to the ambient temperature at that time,and the rinsing can be carried out for 24-36 hours,and then packed with the bamboo shoots and the prepared fermentation both in a steaming bag and sterilize it in a vacuum package to obtain a water-dried bamboo shoot with suitable taste and good preservation effect.(5)After superfine pulverization and screening bamboo shoots with more than 200 meshes can not only effectively extend the shelf life of bamboo shoots powder,but also retain the nutrients of bamboo shoots,and can also be added to biscuits,health products,noodles,solid drinks and capsules and in other types of products,in order to increase the dietary fiber content of the product,the application scope of bamboo shoots will be expanded,and the industrial chain of bamboo shoots will be extended.At the same time,this technology can be further applied to the milling of other fruits and vegetables,providing a new way for companies to produce products that are market-oriented.Taking biscuits as an example,the best formula for dietary fiber biscuits with high fiber of bamboo shoots is high-gluten flour 300 g,bamboo shoot powder 45 g,salt 2.25 g,butter 90 g,and sugar 45 g.After mixing and pelletizing,baked at 185℃ for 10 minutes.Bamboo shoot biscuits containing dietary fiber increase the added value of the product.(6)In accordance with the traditional Sichuan cuisine flavor and the preparation method of compound seasonings,the developed multi-flavored ready-to-eat,fast-food bamboo shoot products of meat dishes have portable nutrition and are in line with contemporary fast fashion.For example,spicy pork-flavored bamboo shoots are based on 80% bamboo shoots,with 10%spicy and 10% pork flavorings added. |
PDF Full Text Request