椰子水饮料贮藏稳定性及流变学特性的试验研究

    Experimental study on storage stability and rheological property of coconut water beverage

    • 摘要: 椰子水饮料在贮藏过程中会出现沉淀和悬浮物等问题,直接影响产品的外观品质和流变学特性。该文以椰子水饮料为试验材料,系统研究椰子水饮料在4℃冷藏、20℃室温和37℃保温贮藏条件下,各营养成分的变化和货架期,并采用流变仪测定椰子水饮料的流变学特性,揭示椰子水饮料的流变特性与贮藏稳定性之间的关系。研究结果表明,椰子水饮料在4℃冷藏条件下贮藏50 d,固形物含量、pH值、总酸度、Vc含量变化均不大,pH值由(4.5±0.01)降至(4.48±0.02),固形物质量分数在(4.5±0.03)%~(5.0±0.02)%波动,总酸度由(1.01±0.01)g/L降至(0.94±0.01)g/L,Vc损失(6.0±0.03)%,稳定程度较好,细菌菌落总数小于100 CFU/mL。椰子水饮料的流变学特性表现为典型假塑性流体,在剪切速率为200 s-1温度从4℃升高至40℃时,其黏度从(0.018±0.003)mPa·s升高至(0.030±0.001)mPa·s,体系黏度随着温度变化程度更缓和,对温度的敏感程度低,具有良好的贮藏稳定性。该试验研究可以为中国实践生产椰子水饮料的品质变化提供理论依据。

       

      Abstract: Abstract: During the storage period, some kind of quality problems exist in a coconut water beverage such as precipitation and suspension, which could affect the quality and stability of the product. This paper attempted to analyze the influence of storage temperature and storage time on the physical and chemical indicators of a homemade coconut water beverage, commercial coconut water beverage, and natural coconut water, as well as the rheological property of each coconut water beverage was researched in detail. In this paper, the homemade coconut water beverage, commercial coconut water beverage, and natural coconut water were used as material and their storage stability were studied in detail, which involved storage at 4℃ refrigerated, 20℃ room temperature, and 37℃ condition along with t variation of nutrient composition and shelf life. The study aimed at revealing the relationship between rheological property and storage stability of the coconut water beverage. The rheological property of each coconut water beverage was measured by rheometer. The results indicated that the components and contents of the physical and chemical indicators were significantly different in those samples, but the solid content, pH value, total acidity, and Vc didn't change significantly at a 4℃ refrigerated storage condition, including a pH value from 4.5±0.01 to 4.48±0.02, solids content from (4.0±0.03)% to (5.0±0.02)%, total acidity from (1.01±0.01) g/L to (0.94±0.01) g/L, the loss of vitamin content was less than (6±0.03)%, the coconut water beverage with better stability, and the total number of bacterial colonies was less than 100 CFU/mL, respectively. Therefore, the quality of coconut water beverage presented good stability at 4℃ refrigerated for 50 days. It was found that the rheological property of coconut water beverage was a typical pseudo-plastic fluid. While the shear rate of 200 s-1 along with a temperature rise from 4℃ to 40℃, the viscosity increased from (0.018±0.003) mPa·s to (0.030±0.001) mPa·s, the system viscosity along with the change of temperature is more moderate, and the effect of temperature on a coconut water beverage system was not obvious, so the storage stability of a coconut water beverage kept well at 4℃. The coconut water beverage was rich in nutrition, and was a product with potential in the beverage market, and it has attracted increasing consumer concern. The storage stability was a key indicator in control of coconut water beverage quality. This would solve the precipitation, taste. And storage issues of coconut water beverage, providing a more reliable theoretical basis for developing the research of quality and nutrition in coconut water beverage and the construction of a quality evaluation system. It was believed that we would produce coconut water beverage with the original flavor, good quality, more freshness and more stability in the future.

       

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