Isolation of Flavor Compounds from Protein Material

Abstract

The nature of the matrix of spray dried whey protein concentrate or sodium caseinate leads to difficulties in efficiently recovering volatiles for flavor analysis. Although recovery of volatiles is more efficient from aqueous solution the reversible adsorption of flavor compounds to proteins also hinders extraction. Low pressure distillation, solid phase micro extraction (SPME) and purge and trap were compared as methods for extraction of volatile compounds from the two protein products. Low pressure distillation recovered the widest range of compounds while purge and trap was best for the most volatile of compounds. SPME accentuated the extraction of carbonyl compounds.A study of the volatile components of dairy protein products is an essential part of developing an understanding of the mechanisms of flavor formation. Sodium caseinate and whey protein concentrate (WPC) powders are manufactured by drying from aqueous solution using the spray drying process. These products are then usually presented for analysis in powder form. Although each powder has a low intensity characteristic odor they are tasted after dissolving in water. Volatile analysis is possible in the powder form but better results are obtained from aqueous solution. An explanation of the physical process of spray drying shows why this is so (7). During spray drying atomised protein solution is heated by hot air. The surface of the particles begins to dry while water and dissolved volatile compounds diffuse towards the surface of the particle. Drying occurs rapidly at the surface and a semi-permeable membrane begins to form. The rate at which molecules migrate towards the surface depends on their diffusivity which decreases with increasing molecular size. As the porosity of the surface membrane decreases the size of molecules able to escape from the particles decreases until eventually only water is able to escape. This process takes only a few milliseconds and, provided the spray dryer operating parameters are correctly chosen, flavor volatiles are substantially encapsulated in the particle during drying. The semi permeable membrane restricts release of volatiles from the powder and it is therefore easy to see why the odor of dairy protein powders is low compared with the odor of their solutions.A further problem is encountered when attempting to extract flavor compounds from protein solutions. This is due to the interaction of flavor compounds with proteins. The nature of this interaction has been studied in mixtures of whey proteins

The Impact of Antioxidant Addition on Flavor of Cheddar and Mozzarella Whey and Cheddar Whey Protein Concentrate

“…Volatiles identified in Cheddar WPC included 2‐methyl butanal, 3‐methyl butanal, pentanal, hexanal, heptanal, octanal, nonanal, dimethyl disulfide (DMDS), 2‐heptanone, 1‐pentanol, 2,5‐octanedione, 2‐pentyl furan, butanoic acid, and hexanoic acid (Table 7 and Figure 1) . Previous research has documented these volatile compounds in Cheddar WPC (Stevenson and Chen 1996; Mills and Broome 1997; Quach and others 1999; Mahajan and others 2004; Carunchia‐Whetstine and others 2005; Wright and others 2009). As with fluid whey, the compounds 2‐methyl butanal and 3‐methyl butanal were only detected in WPC with added WPH.…”

An investigation for the development of whey-based probiotic beverages

“…Hexanal, acetic, butanoic and hexanoic acid were determined in this study. MILLS & BROOME [49] have isolated whey protein concentrate such as ethyl acetate, 2,3-butanedione, hexanal, dimethyl trisulfide, 2-nonanone, nonanal and volatile acids that acetic, butanoic and hexanoic acids.…”

Parts per quadrillion level ultra-trace determination of polar and nonpolar compounds via solvent-free capillary microextraction on surface-bonded sol–gel polytetrahydrofuran coating and gas chromatography–flame ionization detection

“…Single-phase SPME coatings include polydimethylsiloxane (PDMS) [12], polyacrylate [3], carbopack [13], polyimide [14], polypyrrole [15], and molecularly imprinted materials [16,17]. Among the composite coatings are carbowax/divinylbenzene (CW/DVB) [18], polydimethylsiloxane/divinylbenzene (PDMS/DVB) [19], polydimethylsiloxane/carboxane (PDMS/carboxane) [20], and carbowax/templated resin (CW/TPR) [20].…”