常压浓缩和真空浓缩对浓缩椰浆的品质影响

Effect of atmospheric concentration and vacuum concentration on the quality of concentrated coconut milk

首先分析了常压浓缩和真空浓缩制备浓缩椰浆时真空度、温度和时间对椰浆浓缩率、p H与感官品质的影响,然后对常压浓缩椰浆和真空浓缩椰浆的感官品质、质构特性和贮藏性进行了比较。结果表明,常压浓缩在90℃下浓缩120 min时,浓缩率可达49.6%,但椰浆有分层和褐变现象;而在真空度0.75、温度45℃下浓缩60 min,浓缩率可达51.7%,椰浆无分层和褐变现象。质构特性和感官品质分析表明,真空浓缩椰浆的感官品质更好,粘附性、弹性、胶粘性和咀嚼性更小;在37℃下贮藏30 d后,真空浓缩椰浆的菌落总数、p H、酸度和过氧化值均无显著性变化;而常压浓缩椰浆在21 d后的酸价、过氧化值和菌落总数显著增加(p<0.05),p H减小为4.5,品质下降。

Firstly,the effects of vacuum degree,temperature and time on the concentration percentage,p H and sensory of concentrated coconut milk（CCM） prepared by atmospheric concentration and vacuum concentration were studied. Then the texture characteristics,sensory quality and storability of the concentrated coconut milk obtained by atmospheric concentration were compared with that of concentrated coconut milk produced by vacuum concentration. Results showed that the concentration percentage of CCM prepared by atmospheric concentration was 49.6% when the concentrated temperature was 90 ℃ and time was 120 min. Compared with atmospheric concentration,the concentration efficiency of CCM could reach to 51.7% when the vacuum degree was 0.75,temperature was 45 ℃ and time was 60 min,and the CCM looked white and without brown and separation of oil-water. Moreover,test of texture characteristics and sensory quality showed that the CCM produced by vacuum concentration exhibited better texture characteristics. After stored at 37 ℃ for 30 days,the acidity,colony unit forming and peroxide value of the CCM with vacuum concentration were not obviously changed. Whereas,the acidity,colony unit forming and peroxide value of the CCM gained with atmospheric concentration increased（p〈0.05）,and its p H obviously decreased to 4.5.