Modeling the settling behavior in virgin olive oil from a horizontal screw solid bowl

Investigation on sweaty off-flavors in small mill sesame oil and its formation mechanism via molecular sensory science, preparative gas chromatography, and microbiomics

The distinctive and enjoyable aroma of small mill sesame oil (SMSO) originates from the aqueous extraction process. However, in the sedimentation stage in industrial production, when the external ambient temperature is elevated, unpleasant sweaty off-flavors may be present from an unknown source. Based on the odor screening and verification strategy, 76 volatile flavor compounds were identified in different SMSOs, and 3 key areas had a sweaty odor via gas chromatography olfactometry (GC-O) analysis. The validation experiment utilizing preparative gas chromatography (pre-GC) confirmed the sweaty off-flavors were butyric acid, 2-methylbutyric acid, and isobutyric acid, with odor activity values ranging from 1 to 100. Furthermore, microbiological investigations on sesame residues gathered during the sedimentation process at various temperatures revealed sweaty off-flavors were mostly attributed to the collaborative interaction of Lactobacillus, Yarrowia lipolytica, and butanoate 1-phosphotransferase. This study offers a fundamental theoretical foundation for enhancing the quality control and flavor of SMSO.

Study of virgin olive oil clarification by settling under dynamic conditions

BACKGROUND

Vertical centrifugation is the main method for virgin olive oil (VOO) clarification. However, in recent years, settling tanks are also being used to clarify the oils from decanters. They can operate under static or dynamic conditions. In this work, vertical centrifugation and settling under dynamic conditions for VOO clarification and their effects on VOO characteristics were compared.

RESULTS

VOO quality parameters were not affected by the clarification systems studied. The vertical centrifugal separator (VCS) showed higher clarification efficiency, giving clarified oils with higher phenol content and better sensory characteristics. VOOs clarified by dynamic settling showed notable losses of phenols and worse sensory characteristics, since the tank purge system was not efficient, with most of the impurities remaining in the tanks.

CONCLUSION

The VCS with minimal water addition is a quick operation with low water consumption and is a better option to produce VOOs of improved quality, especially in terms of longer shelf life and preservation of positive sensory notes. © 2018 Society of Chemical Industry.

Settling of virgin olive oil from horizontal screw solid bowl in static conditions

This work was aimed to study the clarification efficiency of natural decantation in settling tank on virgin olive oil obtained from a two-ways continuous process. For this purpose, the impurities content of the virgin olive oil were monitored during settling process in settling tank at two different depths. Efficiency of purging system was determined for two days. The experiments were performed at industrial scale during three crop years. During the first minutes of settling was observed an ascent of the smaller organic particles of the oil. Then, most of the virgin olive oil impurities were settled at 300 min, independently of the initial content of virgin olive oil. Finally, oil decantation showed slower rate. Higher clarification values were obtained for those decanter oils with higher impurities content, achieving clarification percentages between of 62.69 and 95.91% at 48 h of settling. The highest settling efficiency was observed for those decanter oils with initial higher impurities content. The purging system used in the settling tanks was not able to remove the most of settled impurities since a considerable amount of the impurities remained in the tank after 48 h, between 13.6 and 71.41% for the studied oils. In the tank purges was observed important oil losses. Therefore, decantation was not an efficient system for oil clarification since its settling capacity varied depending on the initial impurities content and due to the settled impurities can not be removed fully by purging system.