Experimental design and chemometric techniques applied in electronic nose analysis of wood-aged sugar cane spirit (cachaça)

Abstract

Wood barrel aging distilled beverages corresponds to a process capable of aggregate flavor compounds that may change sensory profiles and improve distillates quality. The analysis of the flavor compounds to determine degree of maturation of distillate relies most on costly techniques such as chromatography, so that more affordable and less laborious technologies may be suitable for wood-derived flavor determination in beverages, such as digital olfactometry. An electronic nose system reliability may take into consideration appropriate sample preparation method in order to obtain optimal performance over detection of odor compounds. An optimized pre-injection method was established for cachaça analysis in an electronic nose system after an experimental Rotational Central Composite Design, considering the sample preparation factors: incubation temperature, samples ethanol content, stirring period and equilibrium period. Raw data underwent the chemometric technique Multiple Co-inertia Analysis for feature extraction in prior to optimization design. The chemometric approach for data pre-treatment and analysis demonstrated favorable performance for electronic nose application. The optimal sample preparation included dilution of the aged distillate to lower ethanol content (10% v/v), sample incubation at 49 °C and excluded stirring and equilibrium stages, leading to a simpler and less time-consuming protocol.

Keywords

• Electronic nose
• Optimization design
• Chemometric approach
• Surface response
• Distilled beverage