Changes in the volatile profile of skim milk powder prepared under different processing conditions and the impact on the volatile flavor profile of model white chocolate

The objective of this work is to determine the extent to which changes in the skim milk powder (SMP) manufacturing process alter the volatile profile of SMP, and whether these changes are carried through to a final product when the SMP is used as an ingredient and subjected to further processing. The manufacture of SMP is a multistage process involving a preliminary concentration step, heat treatment and a drying stage. However, the methods and conditions used by the industry are not standardized, and the inherent variability in the production of SMP has consequences for the end-users, such as the confectionery industry, where the SMP is used as an ingredient during the production of milk chocolate, white chocolate and caramel. This study investigates the impact of each stage of the manufacturing process on the concentration of reducing sugars and available amino groups (as precursors of the Maillard reaction) as well as on the volatile products of the Maillard reaction and lipid degradation. Eight types of SMP were produced using combinations of different processing conditions: concentration (by evaporation or reverse osmosis), heat treatment (low heat or high heat) and drying (spray-drying or freeze-drying). Maillard precursors were quantified after each processing stage and volatile compounds were extracted using solid-phase microextraction, and analyzed by GC-MS. The resulting SMPs were incorporated into a model white chocolate system, produced under varying conching conditions. We demonstrate not only that changes in the SMP manufacturing conditions affect the volatile profile of SMP, but also that these differences can be carried through to a final product when the SMP is used to prepare a model white chocolate. Understanding these differences is important to the industry for controlling the flavor of the end product

The impact of the skim milk powder manufacturing process on the flavor of model white chocolate

Milk powder is an important ingredient in the confectionary industry but its variable nature has consequences for the quality of the final confectionary product. This paper demonstrates that skim milk powders (SMP) produced using different (but typical) manufacturing processes, when used as ingredients in the manufacture of model white chocolates, had a significant impact on the sensory and volatile profiles of the chocolate. SMP was produced from raw bovine milk using either low or high heat treatment, and a model white chocolate was prepared from each SMP. A directional discrimination test with naïve panellists showed that the chocolate prepared from the high heat SMP had more caramel/fudge character (p<0.0001), and sensory profiling with an expert panel showed an increase in both fudge (p<0.05) and condensed milk (p<0.05) flavor. GC-MS and GC-Olfactometry of both the SMPs and the model chocolates showed a concomitant increase in Maillard-derived volatiles which are likely to account for this change in flavor

Flavour distribution and release from gelatine-starch matrices

© 2020 The Authors Microstructure design of protein-polysaccharide phase separated gels has been suggested as a strategy to nutritionally improve food products. Varying the phase volumes of a phase separated matrix may affect texture and overall flavour balance of the final product, which are both important for consumer acceptance. The aims of this study were to investigate how modifying the phase volumes of a gelatine-starch biphasic mixture affected aroma release, and how addition of sucrose affects phase separation, flavour distribution and aroma release. Biphasic gels of different microstructures with the same effective concentration of gelatine and starch in each phase were developed. Microstructure significantly affected aroma release in vitro but not in vivo when panellists (n = 5) chewed and swallowed the sample. Addition of sucrose (0–60%) to the biphasic mixture significantly reduced water activity, affected the microstructure and affected aroma distribution in each phase and subsequent release rates depending on the physicochemical properties of the aroma volatile. In general, affinity for the gelatine phase for the less hydrophobic, more volatile compounds was not significantly affected by sucrose concentration. Whereas an increased affinity for the starch phase for the more hydrophobic, less volatile compounds was observed with increased sucrose as the starch phase becomes more dispersed at sucrose concentrations between 40 and 60%. The results of this study may be of interest to researchers and industry to enable prediction of how reformulation, such as reduction of sucrose, to meet nutritional guidelines may affect the overall aroma balance of a phase separated food matrix

Reducing sugar and aroma in a confectionery gel without compromising flavour through addition of air inclusions

Sugar plays an important role in both the flavour and structure of confectionery. Targets have been set to reduce sugar; however, common strategies often result in changes in flavour and consumer rejection. In this study, an approach was developed to reduce sugar in confectionery gels by aeration, without significantly affecting perceived chewiness. Gelatine based gels with a 23% and 38% reduction in density were formulated using aeration. Mean bubble size was consistent across all gels (0.05–0.06 mm). Time-intensity sensory evaluation was carried out by a trained sensory panel (n = 10). With aeration, no significant difference in overall flavour perception was observed in the 23% and 38% reduced sugar and aroma gels. Air inclusions create a greater surface area, therefore accelerating mass transfer of volatiles and release of sucrose at the food-saliva interface. Consequently, we propose that less calorie dense products can be produced without compromising flavour by using gel aeration technologies

Systematic studies on the chemical structure and umami enhancing activity of Maillard-modified guanosine 5'-monophosphates

Recent investigations on taste active principles in nucleotide rich yeast extracts led to the discovery of (R)- and (S)-N(2)-(1-carboxyethyl)-guanosine 5'-monophosphate as previously not reported umami enhancing molecules formed upon the Maillard reaction of guanosine 5'-monophosphate (5'-GMP) with dihydroxyacetone and glyceraldehyde, respectively. In the present study, systematic Maillard-type model reactions were performed with 5'-GMP and a homologous series of monosaccharides exhibiting a C(3)- to C(6)-carbon skeleton as well as with the reducing disaccharide maltose in the presence of an amino acid. By preparative RP-HPLC, various (R)- and (S)-N(2)-(1-carboxyalkyl)-guanosine 5'-monophosphates and (R)- and (S)-N(2)-(1-alkylamino)carbonylalkyl)guanosine 5'-monophosphates were isolated and identified by means of LC-MS, LC-TOF-MS, and 1D/2D-NMR spectroscopy. Sensory evaluation of these Maillard products revealed beta-values for umami enhancement between 0.06 and 7.0 and identified a strong influence of the stereochemistry as well as the chain length of the N(2)-substituent on the umami enhancing activity. For all of the compounds evaluated, the (S)-configured isomers showed higher taste impact, whereas the (R)-isomers showed only marginal beta-values, thus underlining the stereospecifity of the umami taste receptor binding site

Stereoselective synthesis of amides sharing the guanosine 5'-monophosphate scaffold and Umami enhancement studies using human sensory and hT1R1/rT1R3 receptor assays

Recent studies led to the identification of umami-enhancing (S)-N(2)-(1-carboxyethyl)- and (S)-N(2)-(1-alkylamino)carbonylalkyl)guanosine 5'-monophosphates that, together with their sensorially inactive (R)-stereoisomers, were found to be formed upon Maillard-type glycation of guanosine 5'-monophosphate (5'-GMP) with 1,3-dihydroxyacetone or glyceraldehyde, respectively. As the efficiency of this Maillard-type procedure to generate the amidated derivatives is limited by the low solubility and reactivity of long-chain alkyl amines as well as by the tedious separation of the diastereomers formed, a versatile synthesis for the (R)- and (S)-configured amides of N(2)-carboxyalkylated guanosine 5'-monophosphate was developed. Sensory evaluation of a series of N(2)-(1-alkylamino)carbonylalkyl)guanosine 5'-monophosphates revealed beta-values for umami enhancement between 0.1 and 7.7 and identified a strong influence of the stereochemistry as well as the chain length of the N(2)-substituent on the umami-enhancing activity. The observed sensory impact of the (S)-configured isomers was confirmed by recording the enhancing effect of these nucleotides on the l-glutamate-induced response of the functionally expressed T1R1/T1R3 umami receptor in a cell-based assay, thus underscoring the stereospecifity of the umami taste receptor binding site

Discovery of N2-(1-carboxyethyl)guanosine 5'-monophosphate as an umami-enhancing maillard-modified nucleotide in yeast extracts

Sensory-guided fractionation of a commercial yeast extract involving medium-pressure RP-18 chromatography and ion-pair chromatography, followed by LC-MS/MS, LC-TOF-MS, 1D/2D-NMR, and CD spectroscopy, led to the discovery of the previously not reported umami-enhancing nucleotide diastereomers (R)- and (S)-N(2)-(1-carboxyethyl)guanosine 5'-monophosphate. Model experiments confirmed the formation of these diastereomers by a Maillard-type glycation of guanosine 5'-monophosphate with dihydroxyacetone and glyceraldehyde, respectively. Sensory studies revealed umami recognition threshold concentrations of 0.19 and 0.85 mmol/L for the (S)- and (R)-configured diastereomers, respectively, and demonstrated the taste-enhancing activity of these nucleotides on monosodium l-glutamate solutions

Taste active- and taste modulating compounds in yeast extracts and studies on the <i>Maillard</i> reaction of Guanosine 5’-monophosphate

Mittels Kombination instrumenteller Analytik und humansensorischer Methoden erfolgte die molekulare Objektivierung des Geschmacks von Hefeextrakten. Folgende Studien zur Maillard-Reaktion des für Hefeextrakte wertgebenden Guanosin-5’-monophosphat resultierten in der Identifizierung verschiedenster Transformationsprodukte deren Vorkommen in Hefeextrakten mittels LC-MS/MS validiert wurde. Darüber hinaus erfolgte die strukturelle Charakterisierung verschiedener Stoffklassen basierend auf dem Guanosin-5’-monophosphat-Gerüst, die sowohl humansensorisch als auch mittels zellbasierten Geschmacksrezeptor-Assays untersucht wurden. Die erhaltenen Ergebnisse schaffen die wissenschaftliche Grundlage zum Verständnis des Geschmacks von Hefeextrakten sowie zur Maillard-Reaktion von Guanosin-5’-monophosphat was die Möglichkeit bietet neuartige Reaktionsaromen auf Basis von nukleotidreichen Hefeprodukten zu entwickeln.By means of a combination of instrumental analytical and human-sensory methods the molecular definition of yeast extract taste was achieved. Following studies on the Maillard reaction of valuable yeast extract ingredient guanosine 5’-monophosphate resulted in the identification of several transformation products, which were identified in yeast extracts by means of LC-MS/MS. Furthermore the structural characterization of different compound classes based on the guanosine 5’-monophosphate scaffold was achieved, which were investigated by human-sensory and cell-based taste receptor assays. The results create the scientific base for the understanding of yeast extract taste and the Maillard reaction of guanosine 5’-monophosphate. This allows the development of novel process flavours based on nucleotide rich yeast products