Production of tomato flavor volatiles from a crude enzyme preparation using a hollow-fiber reactor

Abstract

In recent years there has been an increase in the interest in the production of compounds by isolation from natural sources or through processes that can be deemed “natural”. This is of particular interest in the food and beverage industry for flavors and aromas. Hexanal, organoleptically known to possess “green character”, is of considerable commercial interest. The objective of this study was to determine if the enzyme template known to be responsible for the synthesis of hexanal from linoleic acid (18:2) in tomato fruits could be harnessed using a hollow‐fiber reactor. A hollow‐fiber reactor system was set up and consisted of a XAMPLER ultrafiltration module coupled to a reservoir. The enzyme template was extracted from ripe tomato fruits and processed through an ultrafiltration unit (NMWC of 100 kDa) to produce a retentate enriched in soluble and membrane‐associated lipoxygenase (LOX) and hydroperoxide lyase (HPL). This extract was recirculated through the lumen of the hollow‐fiber ultrafiltration unit with the addition of substrate in the form of linoleic acid, with buffer addition to the reaction flask to maintain a constant retentate volume. Product formation was measured in the permeate using solid phase microextraction (SPME) developed for this system. At exogenous substrate concentrations of 16 mM and a transmembrane pressure of 70 kPa, hexanal production rates are in the order of 5.1 μg/min. Addition of Triton X‐100 resulted in membrane fouling and reduced flux. The reactor system has been run for periods of up to 1 week and has been shown to be stable over this period. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 67: 372–377, 2000.

New Trends in Food Processing

“…r The application of enzymatic methods to obtain food ingredients, such as the production of tomato aroma (hexanal) using a hollow-fiber reactor (with and enzyme template extracted from ripe tomato fruits) (Cass et al, 2000).…”

Biotechnological Flavour Generation

“…Tomato flavour enzymes were harnessed as a crude enzyme preparation in a commercial ultrafiltration unit, operated as a hollow-fibre reactor to produce hexanal from linoleic acid (Cass et al, 2000). The reactor proved to be stable over an operation period of 5 days, indicating that flavour production with immobilised membrane-associated enzymes in a hollow-fibre reactor is a promising technique.…”

06/02425 Aqueous-organic phases separation by membrane reactors in biodesulfurization reactions

“…This behavior is analogous to that of a pure substance in a ultra-filtering system (Tejada, 1995). A straight-line trend is identified by Luque et al, (1999) and by Cass et al, (2000), while assessing hollowed-fiber membrane modules. Therefore, the lines presented as trends in the graphics are adjusted to a straight line.…”

“…Organic phase separation as of the biosulfurization reaction's emulsion, at different cellular concentrations and at a 25:75 organic/watery phase ratio explains the decrement of permeability flux observed by comparing hexadecane, diesel and emulsion. Cass et al, (2000) reported a reduction in the permeability flux along against transmembrane pressure decrease due to the components present in the enzymatic raw extract used. Figure 4 shows a schematic diagram for the bioreactor's operation.…”

“…An analogous behavior has been described in other researches (Cass et al, 2000;Patankar and Oolman, 1990;Tompkins et al, 2000), and it is considered to be due to the membrane's pore blocking, as caused by the accumulation of cells on its surface (Patankar and Oolman, 1990;Schroën and Woodley, 1997;Luque et al, 1999) and by protein adsorption (Piret and Cooney, 1990;Patkar et al, 1993).…”