Palencia-Blanco Cristian is pursuing his Master’s degree in Chemical Engineering from Industrial University of Santander, Colombia.
The aromatic quality of cocoa liquors has a direct relationship with the volatile compounds present in the different varieties of cocoa (Rodriguez-Campos et al. 2011; Aprotosoaie et al. 2016; Afoakwa et al. 2008). Although the literature is extensive in the identification of compounds associated with the aroma of cocoa, there are few articles that propose methods for their quantification. Normally, quantification is performed by means of an internal standard using a reference compound to quantify all sample compounds (Counet et al. 2004). However, this approach is not accurate because a constant response factor is assumed for all the compounds in the sample. Another approach for quantification is the use of external standards (Bonvehí 2005; Ducki et al. 2008); in this case, a reference compound is used for each compound to be quantified (an external standard per compound); the disadvantage of this approach is the cost associated with the purchase of external standards. This article proposes a semi-quantitative method that includes an internal standard combined with external standards (one per family); in order to obtain a better determination of the concentration volatile compounds aroma precursors in cocoa liquors. For this work, the volatile compounds were extracted from the cocoa liquor using the solid phase micro extraction technique (SPME-HS) and were identified by means of gas chromatography coupled to mass spectrometer (GC-MS) and Kovats retention index. Regarding quantification, toluene was used as an internal standard and a reference compound (present in the sample) was used for each group or family of compounds as an external standard. The method was evaluated using figures of merit like limit of detection (LOD), limit of quantification (LOQ), intermediate precision and percentage of recovery 54 volatile compounds were identified and quantified from the ICS 95 and TCS 01 cocoa varieties produced in the department of Santander, Colombia. The implemented method obtained an LOD and LQD 0.024 μg/kg and 0.037 μg/kg respectively. Regarding accuracy, the proposed method was able to recover up to 96% of the compound of interest in the sample to be analyzed. According to the precision of the method, the results show that the concentrations have an average CV% of 7.38%. Finally, the compounds with the highest concentration were acetic acid (42,633 mg/kg), 2-phenylethyl acetate (29.44 mg/kg), 2-phenylethanol (12,595 mg/kg) and 2, 3, 5, 6-tetramethylpyrazine (8.601 mg/kg) found in the samples analyzed. According to the results presented, this method can be used to determine the concentrations of volatile compounds in cocoa liquors
Denisse Andrea Cáceres Pavez is an Agricultural Engineer. She has obtained her Master’s degree in Agricultural Sciences from The University of Chile. Currently, she is a Doctoral candidate in Nutrition and Food from the Universidad de Chile. She is Laboratory Researcher of Microencapsulation Laboratory of Faculty of Chemical and Pharmaceutical Sciences, University of Chile. She has presented in the Congress of the Agronomic Society in Chile, and has one publication in the journal Postharvest Biology and Technology
Walnut oil (WO) has composition of bioactive compounds such as phytosterols, tocopherols, polyphenols and fatty acid of type omega 6 and 3. However, the presence of polyunsaturated fatty acids (PUFA) makes the WO susceptible to oxidation, generating unpleasant odors and flavors (Calvo et al., 2012). In this context, microencapsulation through spray drying technique, using different biopolymers as encapsulating agents, has been proposed as an effective, economic and scalable alternative to protect oils (Bakry et al., 2016). However, since the oxidation of the oil continues during storage, the incorporation of antioxidants has been proposed. The objective of this work was to study the effect of different designs of WO microparticles varying the location of the antioxidant ethyl gallate (EG) in the parameters of encapsulation and oxidative stability of WO. Three systems of microparticles of WO were studied, using maltodextrin (MD) as encapsulating agent: (1) microparticles based on emulsion of WO without addition of EG (WO-MD); (2) microparticles based on emulsion of WO with EG in the dispersed phase (WO-EGO-MD) and (3) microparticles based on emulsion of WO with EG in the continuous phase (WO-EGA-MD). The WO-EGO-MD system presented the lowest values of TBARs formation and the lowest interfacial tension. This suggest that adding EG as an antioxidant in the dispersed phase would be more effective in preventing the oxidation of the AN, suggesting an arrangement of the EG in the oil-water interface.