Chemical composition of industrialized salad dressings: NMR-based information for a clearer product label

Increasing urbanization and lifestyle changes have made it challenging to maintain a healthy diet, with a growing consumption of ultra-processed foods such as salad dressings. Although the association between ultra-processed food consumption and disease development remains controversial, it is important to note that the composition and labeling of these products often remain unclear and poorly aligned with consumers' needs and understanding. This study aimed to analyze the composition of different salad dressing flavors using proton nuclear magnetic resonance (¹H NMR). Eight salad dressing flavors (balsamic, Caesar, homemade, honey mustard, rosé, Parmesan, soybean sauce, and yogurt) from three distinct brands were evaluated using simple sample preparation methods involving extraction in deionized water, lyophilization, and resuspension in deuterated water. ¹H NMR data revealed the predominant presence of sugars, along with contributions from fatty acids and preservatives/additives. Principal component analysis highlighted significant compositional variability among brands offering the same flavor. Notably, soybean sauce and rosé dressings exhibited the highest relative proportions of sucrose, while one brand of honey mustard dressing had the highest relative level of glucose. Our study demonstrates the effectiveness of ¹H NMR combined with chemometric analysis in characterizing the composition of food matrices such as salad dressings. The predominance of sugars in these traditionally salty foods underscores the need for clearer labeling to help consumers make healthier dietary choices.