Correlating Volatile Lipid Oxidation Compounds with Consumer Sensory Data in Dairy Based Powders during Storage

Abstract

Lipid oxidation (LO) is a recognised problem in dairy powders due to the formation of volatile odour compounds that can negatively impact sensory perception. Three commercial dairy powders, fat-filled whole milk powder (FFWMP), skim milk powder (SMP), and infant milk formula (IMF), stored under different conditions (21 °C, 37 °C, or 25 °C with 50% humidity), were evaluated by consumer acceptance studies, ranked descriptive sensory analysis, and LO volatile profiling using headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME GCMS) over 16 weeks. Significant (p = 0.001) differences in the concentration of LO compounds and sensory perception were evident between sample types in the different storage conditions. The sensory acceptance scores for FFWMP and SMP remained stable throughout storage in all conditions, despite the increased perception of some LO products. The IMF sample was perceived negatively in each storage condition and at each time point. Overall increases in hexanal, heptanal, and pentanal correlated with “painty”, “oxidised”, “cooked”, and “caramelised” attributes in all samples. The concentration of some LO volatiles in the IMF was far in excess of those in FFWMP and SMP. High levels of LO volatiles in IMF were presumably due to the addition of polyunsaturated fatty acids (PUFA) in the formulation.

The Effect of Carnosol, Carnosic Acid and Rosmarinic Acid on the Oxidative Stability of Fat-Filled Milk Powders throughout Accelerated Oxidation Storage

“…In a previous study by Nielsen, Stapclteldt, and Skibsted [ 24 ], whole milk powders stored under accelerated conditions at 50 °C and RH 31% for 49 days also turned progressively darker and more yellow pigmentation, with increasing storage time [ 24 ]. The authors inferred that even if the rate of Maillard reactions, which form brown pigments throughout heat treatment, storage and exposure of milk powders to high temperatures [ 21 ] were reduced with the use of a low RH, they may still have slightly contributed to the colour differences of the different FFMPs after accelerated storage, and particularly after 90 days.…”

“…Levels of pentanal, hexanal and heptanal are good indicators of lipid oxidation in FFMPs [ 21 ], whereas hexanal has been reported as the major compound arising from lipid oxidation of milk powders [ 34 ]. As it was previously stated, samples prior to and during accelerated storage till sampling day 41 had considerably lower concentrations of all the different volatile compounds when compared to the samples tested after 69 and 90 days of accelerated storage (40 °C, RH 23%).…”

“…The STD mix and the ISTD were added at concentrations of 200–1600 µg/L and 1 mg/L in distilled H 2 O, respectively. These compounds were selected as they comprise some of the main compounds arising from the oxidation of sunflower oil (hexanal, 2,4-decadienal, pentanal, 1-pentanol, 2-heptanone, 2-pentanone, octanal, pentanal) [ 20 ] and milk powders (including those previously mentioned for sunflower oil in addition to 3-octen-2-one, 2-nonenal (E), acetone, 2-nonanone and undecanal) [ 19 , 21 ]. For samples after 69 and 90 days of storage, the concentrations were increased to 1–20 mg/L for the STD mix and to 10 mg/L for the ISTD.…”

Detection of Lipid Oxidation in Infant Formulas: Application of Infrared Spectroscopy to Complex Food Systems

“…Hydroperoxides are the first oxidation products and are very reactive, breaking down rapidly to aldehydes, ketones, and other volatiles. These secondary products of lipid oxidation are responsible for rancidity and off-flavors [ 8 ]. Oxidized flavors are noticeable in stored milk at low levels of oxidation (peroxide value <1 meq.O 2 /kg oil).…”

“…Oxidized flavors are noticeable in stored milk at low levels of oxidation (peroxide value <1 meq.O 2 /kg oil). “Fishy” and “metallic” attributes were correlated with increased concentrations of hexanal and heptanal and have been shown to be particularly evident in infant milk formula enriched with LC-PUFA [ 8 , 9 , 10 ]. Moreover, multiple lipid oxidation products (such as free radicals, reactive oxygen species, and aldehydes) may exert detrimental effects on vital biological processes, potentially leading to tissue injuries and increasing the risk for degenerative diseases [ 11 , 12 , 13 ].…”