Optimization of sensory properties of foods

Identification of off-odors and desirable aroma compounds

Identifying the underlying substances that are responsible for off-flavours is indispensable in order to develop suitable avoidance strategies. On the other hand, knowledge of the desirable flavours that impart a product with its special character and increase its acceptance amongst certain consumer groups is essential. We have extensive expertise in the identification of aroma compounds. We utilise state-of-the-art analytical methods to detect and identify aromas and off-flavors on a molecular basis. Knowledge of the specific compounds causing off-flavors is essential in order to draw conclusions to the formation pathways of both desirable and undesirable aroma compounds, thereby enabling off-flavours to be prevented or to promote the development of desirable aromas.

We have expertise in characterizing the transition of off-flavors from packaging materials into food and beverages, and in clarifying their formation pathways. We use this background knowledge to develop bespoke rapid methods for detecting aroma and off-flavor compounds and/or their precursor molecules for subsequent adaptation and validation in cooperation with our clients for in situ use in their commercial quality control processes. We also offer our customers the possibility to develop customised strategies for optimizing flavor development or avoiding off-flavor formation.

Determination of generation pathways of off-odors and off-flavors

Off-flavor investigations target their origins, for example, their potential occurrence from external interferences (e.g., from packaging materials or contaminated raw materials), from different formation processes (e.g., due to thermal, chemical or microbial processes), or through the degradation of constituent, desirable aromas (e.g., evaporation, adsorption or absorption on packaging materials, or due to thermal, chemical or microbial processes) that cause a shift in the flavor profile of a product. Losses of aroma compounds or changes in the flavor of a product during storage can also be monitored to ascertain their causes.
 

Sensory assessments of foods

Our chemo-analytical methods are typically complemented with sensory assessments that are performed with either a trained panel or naïve consumers, according to the specific requirements of a product evaluation.
 

Products and raw materials

We evaluate the aroma and flavor characteristics of diverse product groups and resources including (selected examples):

  • Milk and dairy products, vegetable fats and oils
  • Meat, fish and vegetable protein-based foods
  • Fruit, vegetables and associated products
  • Cereals, flour, bakery products
  • Drinking water, mineral water and beverages
  • Tea, coffee, cocoa
  • Beer, wine, soft drinks and spirits
  • Sweets and confectionary goods

Range of services

  • Human sensory evaluation of food odors and taste, and packaging odors
    Aroma profile analysis (APA), triangle tests, hedonic evaluations

  • Combined instrumental and sensory analyses of odor-active compounds in foods and packaging
    Gas chromatography (GC) coupled with flame ionization detection (GC-FID), olfactometry (GC-O), mass spectrometry (GC-MS), or a combination of these (GC-MS/O and 2D-GC-MS/O). GC sample preparation techniques such as aroma extract dilution analysis (AEDA), Twister®, stir bar sorptive extraction (SBSE), solid-phase micro-extraction (SPME), headspace

  • Studies to identify off-odors
    Elucidation of compounds responsible for off-odor, short and long-term storage tests, precursor studies

  • Simulation of aromas and off-odors on the lab-scale

  • Isolation and purification of odorants
    Various distillation techniques such as solvent assisted flavor evaporation (SAFE) and condensation/trapping techniques

  • Quantitative determination of odorants at trace levels
    e.g. via stable isotope dilution analysis (SIDA), diverse methods for quantification, on-line detection in the gas-phase

  • Monitoring of dynamic release processes of odorants in real-time via in vivo or in vitro studies
    Proton-transfer-reaction mass spectrometry (PTR-MS) and proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS), with calibration using an advanced Gas Calibration Unit (GCU-a)

  • Development of concepts for optimizing desired aroma impressions and investigations into the causes of off-odors with development of avoidance strategies