Study On The Effects Of The Rheological Properties Of Nectar

As pure natural juice, nectar is the treasure of juice beverage, which can farthest hold the dietary fiber and other nutriments of fresh fruit and vegetable, and has good mouthfeel. Nectar is very popular for its high nutritional value, meanwhile its yield and consumption goes up year after year. For the future, it will be the mainstream product of juice. The rheological property is an important parameter of nectar. Knowledge of the rhological properties of nectar is helpful in technics melioration and/or quality control.In this work, some nutritive, marketable fruits and vegetables such as orange, apple, carrot, celery and lily were dealed by ultra-high-pressure homogenization (a new technology in food engineering) to produce juice. The effects of different homogenization pressure on the pH values, pulp granule, soluble solid contents and unsolvable solid contents of nectar were studied. And the rheological behavior of different nectar was studied too, as well as the effect of homogenization pressure, temperature, material content, pulp granule size and material component. Nectar was found to exhibit non-Newtonian behavior. It was found that all of the factors such as homogenization pressure, temperature, concentration, material content, pulp granule size and material component could influence both the flow equations and apparent viscosities of nectar. The effect of temperature on apparent viscosity could be described by Arrhenius equation, the effect of concentration on apparent viscosity could be described by exponential equations. In order to forecast the apparent viscosity five equations including the effects of temperature, pulp content, homogenization pressure (pulp granule size as to celery) on different nectar were obtained.In this work, the effects of each factor including homogenization pressure, temperature, material content, pulp granule size and material component on the rhelogical behavior had been opened out. The results must be helpful in production and exploitation of nectar, application of ultra-high-pressure technology, and development ofrheology.