Changes in color and rheological behavior of pineapple concentrate through various evaporation methods  

作　　者：Rittichai Assawarachan Athapol Noomhorm 

机构地区：[1]Food Engineering and Bioprocess Technology,School of Environment,Resources and Development,Asian Institute of Technology,Klongluang,Pathumthani 12120,Thailand

出　　处：《International Journal of Agricultural and Biological Engineering》2010年第1期74-84,共11页国际农业与生物工程学报（英文）

摘　　要：The objective of this study was to investigate the effect of various concentration methods namely microwave vacuum evaporation(MVE),microwave heating evaporation(MHE),and rotary vacuum evaporation(RVE)on the concentrate change,the kinetic of color degradation,and the rheological behavior of pineapple juice.The concentrated behavior of pineapple juice from the experimental data of concentration rate was fitted with three types of exponential models for evaluating a suitable prediction.The four-parameter exponential model was found to agreeably explain the concentrated change of pineapple juice during each concentration methods.The Kinetics of color change during concentration processes was evaluated.The color changing from three different evaporations was measured by lightness values(L*),redness values(a*)and yellowness(b*)values,total color difference(TCD)and brown pigment formation index(A420).The result indicated that the change in Hunter parameters,L*and b*,fitted well with the first-order kinetic model while a*,TCD,and Browning index followed the zero-order kinetic model.The observed apparent viscosities(μa)of pineapple concentrate at 55-85℃through the three different evaporation methods were also measured.In relation to temperature and shear rate,the viscosity decreased as these two parameters increased,for all concentrated pineapple juice.On comparing the values ofμa of pineapple concentrate from different concentration methods,pineapple concentrate from MHE has higher values than those from MVE and RVE.The Duncan test,applied to the experimental results,indicates no significant difference in theμa of pineapple juice concentrate by MVE and by RVE.

关 键 词：Pineapple juice concentrate microwave vacuum evaporation microwave heating rotary vacuum evaporation kinetic of color change 

分 类 号：R74[医药卫生—神经病学与精神病学]