Variation in the volatiles, total polyphenol, theobromine and caffein was investigated both qualitatively and quantitatively for all phases of conching with GC/MS/SPME, HPLC, GC/O, and UV-visible spectrophotometry. The volatile compounds being identified during the three phases consisted of aldehydes, ketones, pyrazines, acids, alcohols and esters. The number and concentration of these compounds were observed to be 31-25,681 ppb, 44-34,838 ppb and 44-29,809 ppb in the dry, pasty, and liquid phases respectively. The odor of dark chocolate was described as nutty, sweet, caramel, green and chocolate using olfactometry. The percent decrease in the concentration of total polyphenol, caffein and theobromine was observed to be only 3.0, 11.0, and 32.0 respectively.

In the present study, refined dark chocolate mix was conched with the addition of finely powdered cinnamon in a laboratory-style conching machine to evaluate its aroma profile both analytically and sensorially. The analytical determinations were carried out by a combination of solid phase micro extraction (SPME)-gas chromatography (GC)-mass spectroscopy (MS) and-olfactometry(O), while the sensory evaluation was made with trained panelists. The optimum conditions for the SPME were found to be CAR/PDMS as the fiber, 60°C as the temperature, and 60 min as the time. SPME analyses were carried out at 60°C for 60 min with toluene as an internal standard. 26 compounds were monitored before and after conching. The unconched sample had a significantly higher fruity odor value than the conched sample. This new product was highly acceptable according to the overall inclination test. However some of textural properties, such as coarseness, and hardness were below the general preference.