Study On Technology And Equipment Of Coupling Pulping And Enzyme Inactivation By Steam For Apple

Apple is one of the world’s top four fruits,China is a apple production power in the worldwide,apple production has ranked the first place in the worldwide at recent years,it production more then 40 million tons pre year,the deep processing is imperative.Browning has always been a key problem restricting the development of apple juice industry,which seriously affects the color and nutritional components of apple juice.In this paper,We attempts to explore the broken coupling steam inactivation of enzyme properties of pulp on the basis of the design and construction of the pulping equipment,and design and manufacture a certain industrial production capacity of complete sets of equipment,the main research contents and results are as follows:(1)Put forward coupling pulping and enzyme inactivation by steam technology,and a self-designed equipment was set up for process implementation.The results show that the broken coupling steam process can effectively protect the apple pulp from browning,and the inhibition effect has a great relationship with the ending temperature.Further experiments and analysis showed that the apple pulp color was not correlated with the ending temperature,but it had a critical breakpoint near 80℃which related to the enzyme activity in apple pulp.The physical and chemical properties of pulp at 25℃/83℃/93℃ were measured and analyzed,respectively.The broken coupling steam inactivation technology reduced the fruit pulp pH,increased the titratable acid content,but also reduced the sugar in the fruit pulp,which is good for improve the taste of apple juice.The viscosity and turbidity of pulp which stored at 4℃for 42 days were determined and analysed,it showed that the viscosity of the pulp produced by the process of crushing and coupling steam inactivation was slightly larger than that of the conventional method,the turbidity change is smaller,the bottom sediment is less,and the turbidity stability is better in the storage process,which is more conducive to the later preservation.(2)On the basis of physical and chemical properties,the functional components and volatile flavor compounds of pulp at 25℃/83℃/93℃ were determined and analyzed.The contents of polyphenols and flavonoids in the fruit pulp of the process of crushing and coupling steam inactivation were 72.09 and mg/100 g,respectively,which was about 8 times of that of the conventional process.The antioxidant activity of apple pulp was determined and analyzed from two aspects: oxygen free radical scavenging ability and free radical scavenging ability,the ORAC value of the fruit pulp was 2.3 times as much as that of the conventional process and the free radical scavenging rate was as high as 2.5 times that of the conventional process.Checked out 192,217,222 kinds of volatile flavor compounds from pulp at 25℃/83℃/93℃ respectively by GC-MS,and confirmed 45 kinds of flavor substances which relative content is more than 0.1%.There are 12 kinds of alcohols in confirmed,and esters,ketone,alkenes,are 10,6,3,7 kinds of,respectively.The total relative content of C-substances in pulp at 25℃/83℃/93℃ was52.68%,25.61%,20.55%,respectively.Broken coupling steam process although increase of pulp volatile scenery material types,also reduced the content of the main volatile flavor components.The broken coupling steam process has a good effect on improving the active ingredient in apple pulp,but it is inevitable to lose some flavor substances.(3)Color is the most important property of fruit pulp,and it is also affected easily by the process parameters.Response surface analysis and optimization were carried out on three factors which affect the color of the pulp: the temperature at the end of the beating(T),the heating rate(K),and the cooling rate(V),and obtained the best of the process parameters of broken coupling steam inactivation process: the ending temperature was 86.9℃,the heating rate was 2.9℃/s,the cooling rate was 2.9℃/min,and the color of the pulp was L value of 54.9699.(4)The basic principle of impact crushing,impact stress and size reduction ratio are analyzed,design and manufacture a suitable prototype for coupling broken and steam,which has 500 kg/h production capacity.The prototype was tested and the color of apple pulp was bright and stable.The research shows that pulp producted of broken coupling steam process had bright and stable color and high rate of nutrition and flavor retention.It is easy to industrialize scale production,which is a good method to product fresh apple pulp.