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Quantitative X-ray Diffraction Determination of Alpha-Lactose Monohydrate and Beta-Lactose in Chocolate

Nathan R Thomas, Logan S Shumway, Lee D Hansen

J Food Sci. 2009 Sep;74(7):C513-8.

PMID: 19895454

Abstract:

Lactose is a constituent of milk chocolate. During processing and cooling, lactose may precipitate as alpha-lactose monohydrate and beta-lactose. The presence of alpha-lactose monohydrate has a deleterious effect on the quality of milk chocolate. A quantitative X-ray diffraction method for determination of alpha-lactose monohydrate and beta-lactose in chocolate is described. The alpha-lactose monohydrate signal at 19.9 degrees 2theta with Cu-Kalpha X-rays is a cubic function of concentration. The beta-lactose signal at 20.9 degrees 2theta is a linear function of concentration. alpha-Lactose monohydrate is detectible at about 0.1 weight% and can be quantified at >0.5 weight%. beta-Lactose is detectible at about 1 weight% and can be quantified at >3 weight%. About 10 min is required to prepare and run a sample.
Practical application:
The crystalline form of lactose affects the quality of chocolate. A rapid method for quantifying crystalline forms of lactose in chocolate is described. The method can be used for quality control and for improving chocolate quality.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
IAR42410230 D-Lactose-1-13C monohydrate D-Lactose-1-13C monohydrate Price
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