Sensory Characterization of Chemical Components Responsible for Cardboard Flavor in Whey Protein

Abstract

Cardboard flavor is one of the most commonly described off‐flavors in whey proteins. The objective of this research was to identify volatile components that are likely sources of cardboard flavor in dried whey protein concentrate and isolates and characterize them by sensory analysis. Cardboard and brown paper samples (n = 5) soaked in deionized water and whey proteins with and without cardboard flavor were analyzed by gas chromatography mass spectrometry and descriptive sensory analysis to select the potential contributors to cardboard flavor. Compounds were evaluated by trained sensory panelists using sniff jars, dose‐response experiments and whey protein models. Sensory analysis of the aroma of the chemical standards yielded no single compound exhibiting a cardboard aroma, suggesting that cardboard flavor does not result from one compound but a combination. A combination of compounds (pentanal, heptanal, nonanal, 1‐octen‐3‐one, dimethyl trisulfide) elicited cardboard flavor in whey protein previously deemed free of cardboard flavor. PRACTICAL APPLICATIONS This study established that a combination of pentanal, heptanal, nonanal, 1‐octen‐3‐one and dimethyl trisulfide elicited cardboard flavor in whey protein and can be utilized as a training reference for identifying cardboard flavor. The direct association of specific lipid oxidation products with cardboard flavor in whey protein emphasizes the necessity to control lipid oxidation to reduce this off‐flavor in whey protein ingredients. These compounds could potentially be utilized to instrumentally monitor cardboard flavor in whey protein. Hexanal, while a major indicator for lipid oxidation, was not directly indicative of cardboard flavor in whey protein.

Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide

“…Both bleached WPI were higher ( P < 0.05) in hexanal, heptanal, octanal, nonanal, decanal, and 2 pentyl furan than unbleached WPI, all lipid oxidation compounds (Table ). HP WPI was higher ( P < 0.05) in hexanal, dimethyl disulfide, dimethyl trisulfide, z‐4‐heptenal, methional, 1‐octen‐3‐one, and nonanal than the BP bleached WPI, all volatile compounds which have been previously reported in whey products (Wright and others ; Croissant and others ; Evans and others ; Whitson and others ; Listiyani and others ; Jervis and others ; Campbell and others ). BP bleached WPI was only higher than HP in 2‐pentylfuran and 3‐methylbutanal.…”

“…Jervis and others () also reported higher 2‐pentylfuran in BP bleached WPC80 than HP bleached WPC80. Lipid oxidation products, such as the aldehydes found in increased concentrations in the bleached WPI are the source of cardboard flavor (Whitson and others ).…”

Effect of temperature and concentration on benzoyl peroxide bleaching efficacy and benzoic acid levels in whey protein concentrate

“…Bleaching temperature and BP (soluble or insoluble) affected lipid oxidation and protein degradation compounds. The WPC80 bleached by soluble and insoluble BP had higher levels (P > 0.05) of 2 methylbutanal, hexanal, 2-pentyl furan, and nonanal than unbleached WPC80 (results not shown); these volatile compounds have been previously reported in dried whey products (Wright et al, 2006;Croissant et al, 2009;Evans et al, 2010;Whitson et al, 2010;Listiyani et al, 2011; Jervis et al, 2012;Campbell et al, 2013). The WPC80 bleached by insoluble BP at 4°C had higher total aldehyde levels and higher levels of hexanal, 2-pentyl furan, and octanal than WPC80 bleached by soluble BP at 4 or 50°C and WPC80 bleached by insoluble BP at 50°C (Figure 8).…”

“…The WPC80 bleached at 4°C by soluble BP was also higher in cardboard flavor than the unbleached control (P < 0.05). Lipid oxidation products, such as the aldehydes found in elevated concentrations in the WPC80 bleached by insoluble BP at 4°C, are the source of cardboard flavor (Whitson et al, 2010). Sweet aromatic flavor was lower in all BP-bleached WPC80 compared with the unbleached control, and WPC80 bleached at 4°C by insoluble BP had lower sweet aro- BA.…”

The effect of microfiltration on color, flavor, and functionality of 80% whey protein concentrate

“…Intensities were scored using a 0-to 15-point universal scale, with 0 being absent and 15 the highest intensity. Most dried dairy ingredient flavors fall between 0 and 4 on this scale (Wright et al, 2009;Whitson et al, 2010). Means in the same row with different letters are significantly different (P < 0.05).…”