科研之友
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摘要
Evolution of microstructure during heat-induced gelation of beta-lactoglobulin (beta-LG) was investigated in situ using confocal laser scanning microscopy at various gel-preparation conditions: pH = 2, 5, and 7; protein content = 5, 10, and 15%; and salt (NaCl) content = 0, 0.1, and 0.3 M. The number and area of evolving beta-LG clusters were observed as a function of time and temperature and the data were fitted to a log-normal model and sigmoid model, respectively. The gelation temperature (T-gel) of the beta-LG system was determined from both the number (T-gel/N) and total area (T-gel/A) of beta-LG clusters versus temperature data. The range of T-gel/N and T-gel/A values for all the cases was 68 to 87 degrees C. The effect of pH was the most dominant on T-gel/N and T-gel/A, whereas the effects of beta-LG and salt contents were also statistically significant. Therefore, the combined effect of protein concentration, pH, and salt content is critical to determine the overall gel microstructure and T-gel. The T-gel/N and T-gel/A generally agreed well with T-gel determined by dynamic rheometry (T-gel/R). The correlations between T-gel/N and T-gel/A versus T-gel/R were 0.85 and 0.72, respectively. In addition, T-gel/N and T-gel/A values compared well with T-gel/R values reported in the literature. Based on these results, T-gel/N determined via in situ microscopy appears to be a fairly good representative of the traditionally measured gelation temperature, T-gel/R.
- 出版日期2013-9
