Research On Functional Pineapple Juice Reserved Activity Of Bromelain

Pineapple (Ananas comosus L. Merr.) is an important fruit crop in manytropical and subtropical countries. It is commonly consumed as fresh and asprocessed products such as pineapple juice, which is popular due to its pleasantaroma and flavor. Bromelain is the major proteinase in the fruit juice, the continuedinterest in which for its numerous applications in medicine and pharmacology makethis enzyme one of the best vegetal proteases. So it has potentially functionality forpineapple juice reserved activity of bromelain. Ultra high-pressure (UHP), as a newtype of food processing technology, can be capable to secure the freshness andnutritive value, as a result it can avoid the disadvantages caused by heating andsteaming. Previous research of pineapple juice by UHP was emphasized onsterilization and general physical-chemical quality, activity of bromelain in thejuice is less discussed and lack of new product development.In this thesis, we choose Smooth Cayenne as the raw material, and develop thenew functional pineapple juice by UHP technology. The main results are as follows:(1) The appropriate activity range of bromelain in functional pineapple juicewas settled. The enzyme properties and Chinese consumption habits were statedand it could be inferred that the activity value of fresh juice did no harm to people.The enzyme sample were digested in simulated gastric fluid and analyzed byFolin-phenol Reagent Method and SDS-PAGE. Results showed that there wasdigestion resistance of bromelain from pineapple juice in simulated gastric fluidand it has potential dietotherapy function.(2) Three methods for the functional pineapple juice were obtained. The juiceproduced by Option1, pressure of300MPa, temperature of20℃,dwell time of15min, the carbon dioxide gas capacity of2.5(1volume is equivalent to1.84g/L),had the unique taste as carbonated juice.The bromelain activity of the juice was74.15U/g and the total number of colonies was14cfu/mL, which all met therequirements. Other two processing methods were built on the basis of thecharacteristics of bromelain. The processing parameters of Option2were the sameas the optimum program, only not adding carbon dioxide gas, which could decreasethe breakage rate of bottles. Option3utilized the influence of temperature on theenzyme activity and so it would control the value of enzyme activity. The juice insulated in the water at50℃and then treated with UHP technology (pressure of300MPa, co-temperature of20℃, dwell time of15min). All the results of thequality indicator matched the requirements or standards.(3) It was advisable for the three functional pineapple juices to store awayfrom light under the temperature of4℃and their shelf life reached21days. Duringthe storage, the total number of colonies increased slowly. The juice can be safeonly within21days at4℃. The activity of bromelain in the juice A, B and Cdeclined slightly, less than30%. The sensory quality didn’t change significantly,and retention rate of vitamin C was approximately80%.