https://doi.org/10.17113/ftb.57.04.19.6401

Effect of Different Clarification Methods on Volatile Aroma Compound Composition of Virgin Olive Oil

Karolina Brkić Bubola¹*, Marina Lukić¹, Igor Lukić¹ and Olivera Koprivnjak²

¹Institute of Agriculture and Tourism, K. Huguesa 8, 52440 Poreč, Croatia
²University of Rijeka, Faculty of Medicine, Braće Branchetta 20, 51000 Rijeka, Croatia

Article history:
Received: 5 June 2019
Accepted: 25 November 2019

Key words:
industrial filtration, natural sedimentation and decantation, virgin olive oil, volatile compounds, sensory profile

Summary:
This study investigates the effect of industrial scale filtration of fresh monovarietal virgin olive oil from Buža and Istarska bjelica cultivars on their volatiles, total phenols and sensory characteristics, and compares the oil samples clarified by filtration with those clarified by natural sedimentation/decantation after six months of storage. Filtration had a different effect on volatiles from the oil samples obtained from different cultivars. In the oil from Buža cultivar immediately after filtration only the amount of (Z)-2-pentenol slightly increased, but in Istarska bjelica the oil filtration affected eight compounds (the amount of hexanal, (E)-2-pentenal, (Z)-3-hexenal, (Z)-2-pentenol and (Z)-3-hexen-1-ol increased, while of hexyl acetate, (E)-2-penten-1-ol and (E)-2-hexen-1-ol decreased). In fresh filtered oil from Buža cultivar a slight decrease of total phenols was observed, while in those from Istarska bjelica the decrease was sharp, causing a decrease in the pungency and bitterness. Sedimentation/decantation had advantages over oil filtration of both cultivars, due to improved effect on the preservation of the sensory profile and the level of total phenols. Tentative aroma profiles based on odorant series obtained from the odour activity values were compared to the actual olive oil sensory profiles. These results could have a high level of applications in the olive oil industry for the optimization of the technology for obtaining monovarietal virgin olive oil with preserved specific and typical sensory characteristics, but also may serve experts to choose an appropriate virgin olive oil clarification method prior to analysis of volatile compounds.

*Corresponding author:   +38552408341
                                           +38552431659 
                                            karolina@iptpo.hr

https://doi.org/10.17113/ftb.57.04.19.6369

Aronia Berry Processing by Spray Drying: From Byproduct to High Quality Functional Powder


Senka Vidović¹*, Milica Ramić¹, Rita Ambrus², Jelena Vladić¹, Piroska Szabó-Révész² and Aleksandra Gavarić<sup>1


1</sup>Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
²Department of Pharmaceutical Technology, Eotvos 6, University of Szeged, 6720 Szeged, Hungary

Article history:
Received: 10 May 2019
Accepted: 17 December 2019

Key words:
aronia, byproduct, ultrasound assisted extraction, spray drying, powder

Summary:
The main aim of this study is to analyze the solid-liquid extraction followed by spray drying as a technological pathway for utilization of aronia fruit dust, a byproduct of filter tea factory. In the current study, ultrasound-assisted extraction was applied for the production of aronia liquid feed and maltodextrin was used as a carrier and encapsulating agent. In spray drying, the influence of inlet temperature and maltodextrin type and mass fraction on process efficiency and powder properties were observed. The physical and chemical properties of the obtained powders were characterized. It was determined that the powder produced using inlet temperature 140 °C and 40 % maltodextrin with dextrose equivalent (DE) 19.7 had the most desirable characteristics. It was observed that the increase in maltodextrin mass fraction decreases the powder moisture content, hygroscopicity and the content of bioactive compounds, but increases water solubility index and particle size. The increase in dextrose equivalent of maltodextrin increases the powder hygroscopicity and water solubility index, while the increase of inlet temperature causes a decrease in moisture content of aronia powders.

*Corresponding author:   +381 21 485 3731
                                            senka.curcin@yahoo.com
                                                senka.vidovic@tf.uns.ac.rs  

https://doi.org/10.17113/ftb.57.04.19.6063

Supplement

Flocculation and Expression of FLO Genes of a Saccharomyces cerevisiae Mezcal Strain with High Stress Tolerance

Israel Vergara-Álvarez^1,2, Francisco Quiroz-Figueroa³, María Concepción Tamayo-Ordóñez^1,4, Amanda Alejandra Oliva-Hernández¹, Claudia Patricia Larralde-Corona¹ and José Alberto Narváez-Zapata¹*

¹National Polytechnic Institute (Instituto Politécnico Nacional), Center for Genomic Biotechnology, Blvd del Maestro s/n esq, Elías Piña Col. Narciso Mendoza, C.P. 88710, Reynosa (Tamaulipas), Mexico
²Aix-Marseille University, LCB (UMR7283), CNRS, Marseille, France
³National Polytechnic Institute (Instituto Politécnico Nacional), CIIDIR-IPN Unidad Sinaloa, Blvd. Juan de Dios Bátiz Paredes no. 250, Col. San Joachin, C.P. 81101 Guasave (Sinaloa), Mexico
⁴Genetic Engineering Laboratory, Department of Biotechnology, Faculty of Chemical Sciences, Autonomous University of Coahuila, Saltillo Unit, Mexico

Article history:
Received: 26 September 2018
Accepted: 8 November 2019

Key words:
Saccharomyces cerevisiae, flocculation, stress tolerance, fermentation, mezcal, agave must

Summary:
Mezcal is a distillate produced by spontaneous fermentation of the must obtained from stalks of Agave spp. plants that are cooked and pressed. Agave must contains a high amount of fructose and phenolic compounds, and fermentation usually occurs under stressful (and uncontrolled) environmental conditions. Yeasts capable of growing under such conditions usually display advantageous biological and industrial traits for stress tolerance such as flocculation. In this study, seven Saccharomyces cerevisiae strains isolated from mezcal must were exposed to temperatures ranging between 10 and 40 °C, and to different sugar sources (fructose or glucose). Yeasts grown in fructose increased their stress tolerance, determined by colony count in a microdrop assay, under low temperature (10 °C) compared to the growth at 40 °C on solid cultures. The most stress-tolerant mezcal strain (Sc3Y8) and a commercial wine (Fermichamp) strain, used as control, were grown under fermentation conditions and exposed to long-term temperature stress to determine their performance and their potential for flocculation. Compared to glucose, fermentation on fructose increased the metabolite accumulation at the end of culture, particularly at 40 °C, with 2.3, 1.3 and 3.4 times more glycerol (8.6 g/L), ethanol (43.6 g/L) and acetic acid (7.3 g/L), respectively. Using confocal microscopy analysis, we detected morphological changes such as aggregation and wall recognition at the level of budding scars in yeast, particularly in the Sc3Y8 strain when it was exposed to 40 °C. The analysis confirmed that this mezcal strain was positive for flocculation in the presence of Ca2+ ions. Analysis of FLO1, FLO5 and FLO11 gene expression implicated in flocculation in both Saccharomyces strains showed a strong transcriptional induction, mainly of the FLO5 gene in the mezcal Sc3Y8 strain.






*Corresponding author:  jnarvaez@ipn.mx