For the first time, a method based on dispersive solid phase microextraction (D-μSPE) using commercial metal-organic frameworks coupled to liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) has been proposed for the determination of isoflavones in soy drinks. The use of commercial sorbents simplifies the sample treatment procedure and allows their application to routine analysis. Optimization of the parameters involved in the microextraction process was carried out using a Box-Behnken experimental design. Under the optimized conditions, the limits of detection ranged between 2 and 7 μg L-1; the intra-day and inter-day precision were <10 and 20%, respectively, and the recoveries were in the range of 61-120%. No significant matrix effect was found, which allowed the use of external standard calibration method. The method was successfully applied to the determination of isoflavones in commercial soy milk samples.

In Germany, milk and dairy products are increasingly replaced by their plant-based alternatives. Although they can be used as substitutes, they differ significantly in their nutrient composition; thus, substitution could lead to nutrient deficiencies. So far, there are no food-based dietary recommendations that show which foods can replace milk and dairy products in a healthy way when switching to a plant-based substitute.
Against this background, the question arises as to how to ensure adequate intake of critical nutrients when plant-based alternatives are consumed instead of milk and dairy products. To answer this question, this study aims to analyze what dietary changes would be required to avoid possible nutrient deficiencies and what types of foods can be consumed instead.
To answer the research question, 3 different models are compared using the linear programming method: healthy diets with 1) milk and dairy products, 2) nonfortified plant-based alternatives, and 3) fortified plant-based alternatives. The models are applied to omnivorous, pescatarian, and vegetarian diet types.
The results show that when consuming nonfortified soy alternatives, an adequate supply of calcium and, in the case of a vegetarian diet, vitamin B12 can only be achieved if significant dietary changes are made compared to the average diet. This includes a significantly higher consumption of fruit and vegetables, whereby within the groups, calcium-rich varieties should be chosen (e.g., green leafy vegetables). When consuming fortified soy-based alternatives instead, the absence of milk and dairy products can be well compensated by the nutrients currently added to commercially available products.
Given the trend to consume less milk and dairy products or to abstain from them altogether, public health measures should point out possible nutrient deficiencies as well as necessary dietary changes, especially because in Germany, many plant-based alternatives are not fortified.