Heracles 2 electronic nose

Aroma profiles of the four sausage samples were analyzed using a Heracles II electronic nose (Alpha MOS, Toulouse, France) according to the method of Go et al. [12 (link)], with minor modifications. Homogenized sausage samples (5 g) were placed in a 20 mL vial and heated at 60 °C for 20 min. Subsequently, 1 mL of each sample was delivered by the autosampler to the injector at 125 μL/s at 200 °C. The sample was maintained for 20 s at 40 °C in a TENAX absorbent trap. The two columns (MXT-5/MXT-1701, Restek, Bellefonte, PA, USA) were mounted, and the detector temperature was maintained at 260 °C. Subsequently, the distinguished principal component (aroma substance) of the samples was considered as the primary component (PC1) and secondary component (PC2) values. The AlphaSoft software (Alpha MOS, Toulouse, France) was used for classified aroma profiling.

The volatile compounds profiles of herb extracts were analyzed using Heracles II Electronic Nose (Alpha M.O.S., Toulouse, France), equipped with two columns of different polarity (MXT-5 nonpolar and MXT-1701 polar). Main volatile compounds in the samples were detected based on Kovats retention indexes. Analysis parameters were set as follows: injector at 200 °C, oven temperature program 60 °C for 2 s, a 3 °C s⁻¹ ramp to 270 °C, isotherm for 30 s at 270 °C, and flame ionization detectors (FID) at 270 °C. Herb extracts (1 mL) were put into 20 mL glass vials and locked with Teflon-silicon rubber caps. Each vial was incubated at 45 °C for 10 min (under an agitation of 8.33 Hz). After that time, the autosampler injected 3500 µL of gas from the samples (headspace) to the columns (with a rate of 125 mL s⁻¹).

The headspace of the vinegar samples was analyzed using the HERACLES II electronic nose (Alpha MOS) [24 (link),25 (link)]. The HERACLES II was equipped with two identical gas chromatography columns working in parallel mode: a nonpolar column (MXT-5) and a polar column (MXT-WAX) that produced two chromatograms simultaneously. Two columns of MTX-5 and MTX-1701 were mounted in parallel and analyzed using two flame ionization detectors. The temperature of the sample increased at 1 °C per second from the initial temperature of 40 °C to 80 °C while it passed through the column, and from 80 °C, the temperature increased at 3 °C per second and the sample was analyzed until it reached a temperature of 250 °C. The experiment was repeated three times to analyze the difference in the relative content of the components between the samples. The principal component analysis (PCA) and statistical quality control (SQC) analysis was conducted using the AlphaSoft 14.2 ver. software (Alpha MOS).

The Heracles II electronic nose (Alpha M.O.S., Toulouse, France) based on ultrafast gas chromatography was applied to analyze the volatile compounds of the fixed oils according to the method described by Wojtasik-Kalinowska et. al. [42 (link)]. Briefly, 1 g of oil was placed in glass vials (20 mL) and capped with a Teflon-faced silicon rubber cap. The vials were placed in the automatic sampler. Each vial was incubated at 50 °C for 10 min under agitation at 500 rpm. The accumulated gas in the headspace was then injected into GC with 10 m lengths, 0.18 mm internal diameter two different polarity columns, non-polar MXT-5 (5% diphenyl) and semi polar MXT-1701 (14% cyanopropylphenyl), with two flame ionization detectors (FID). The injected volume was 2500 µL, and the injector temperature was 200 °C. The temperature of the two flame ionization detectors was 270 °C. The injection on the e-nose was carried out on 3 replicates. The method was calibrated using an alkane solution (n-butane to n-hexadecane) in order to convert retention time in Kovats indices and to identify the volatile compounds using the AroChemBase database.

The Heracles II electronic nose (Alpha M.O.S., Toulouse, France) based on ultrafast gas chromatography was applied to analyze the volatile compounds of beef patties with berry pomace additives, according to the method described by Wojtasik-Kalinowska et al. [31 (link)]. Briefly, 3 g of beef patties meat was placed in glass vials (20 mL) and capped with a Teflon-faced silicon rubber cap. The vials were placed in the automatic sampler. Each vial was incubated at 50 °C for 10 min under agitation (500 rpm). The carrier gas, hydrogen, was circulated at 1 mL min⁻¹. The accumulated gas in the headspace was then injected into GC with 10 m length, 0.18 mm internal diameter, two different polarity columns non-polar MXT-5 (5% diphenyl) and semi-polar MXT-1701 (14% cyanopropylphenyl) with two flame ionization detectors (FID). The injected volume was 2500 µL and the injector temperature was 200 °C. The temperature of the two flame ionization detectors was 280 °C [32 (link)]. The injection on the e-nose was carried out on three replicates. The method was calibrated using an alkane solution (n-butane to n-hexadecane) in order to convert retention time into Kovats indices, and to identify the volatile compounds using the AroChemBase database.