A new testing method for vital gluten swelling index

作者：Hu XinZhong; Shang YaNing

来源：Journal of the Science of Food and Agriculture, 2007, 87(9): 1778-1782.

DOI：10.1002/jsfa.2925

• vital gluten
• vital gluten swelling index
• water absorption
• insoluble glutenin

Vital gluten is a kind of functional protein, but currently its quality indices are mostly focused on the outer character rather than the inner content. The objective of this study was to develop an improved testing method for the measurement of vital gluten, reported here as the vital gluten swelling index (VGSI). The procedures were optimized using the vital gluten water absorption ratio and the wheat flour protein fraction content. The following procedure is recommended: use 0.9 mL distilled water to hydrate 20 mg vital gluten for 10 min, and then add 0.9 mL of 0.03 g kg(-1) sodium dodecyl sulfate-lactic acid solution and mix for another 30 min. Finally, centrifuge the mixture at 5000 x g and measure the residue weight. The quality of vital gluten can be simply classified by its swelling index value. A VGSI of >= 28% indicates vital gluten of superior grade, between 24% and 28% is a good grade, while <= 24% is an inferior grade. Compared with the laborious method of vital gluten water absorption (VGWA), which takes a relatively long time to test one sample, VGSI requires only 47 min to test 24 samples. Further, the VGSI method is more accurate, reliable and repeatable. The coefficient of variation of VGWA of the vital gluten samples is 2.09, while the corresponding value for VGSI was 14.83. The correlation coefficients between VGSI and other vital gluten indices were significant. The research indicates that the method developed is the best to evaluate vital gluten.

• 出版日期2007-7