Qualitative differences of divalent salts: multidimensional scaling and cluster analysis

Area of Science:

• Sensory science
• Chemosensation
• Taste perception

Background:

• Understanding taste perception is crucial for food science and nutrition.
• Divalent metal salts are common in foods and beverages, influencing sensory profiles.
• Previous research suggests unique sensory properties for these salts, but detailed characterization is needed.

Purpose of the Study:

• To investigate and characterize the distinct sensory sensations evoked by divalent metal salts (iron, calcium, magnesium, zinc).
• To differentiate these sensations from the four primary tastes (sweet, sour, salty, bitter) and astringency.
• To explore the influence of retronasal cues on salt perception.

Main Methods:

• Utilized a sorting task and multidimensional scaling (MDS) to analyze similarity judgments of divalent salts.
• Controlled salt concentrations to equalize mean intensity ratings.
• Examined sensory perception with and without nasal occlusion to isolate olfactory contributions.
• Included compounds representing primary tastes and astringency for comparison.

Main Results:

• Divalent salts formed distinct clusters outside the perceptual space of the primary tastes.
• Iron salts were characterized by unique metallic sensations and astringency when nasal cues were present.
• Calcium and magnesium salts were primarily perceived as bitter.
• Zinc salts were predominantly characterized by astringency.
• In the absence of nasal cues, bitterness and astringency largely explained the sensations from divalent salts.

Conclusions:

• Divalent metal salts possess unique sensory profiles that are distinguishable from primary tastes.
• Metallic sensations are a key characteristic of iron salts, often accompanied by astringency.
• Bitterness and astringency are significant contributors to the overall perception of divalent metal salts, especially without olfactory input.
• These findings provide a detailed sensory map of common divalent salts, relevant for food and beverage formulation.