Astringency of bovine milk whey protein

Whey protein solutions at pH 3.5 elicited an astringent taste sensation. The astringency of whey protein isolate (WPI), the process whey protein (PWP) that was prepared by heating WPI at pH 7.0, and the process whey protein prepared at pH 3.5 (aPWP) were adjusted to pH 3.5 and evaluated by 2 sensory analyses (the threshold method and the scalar scoring method) and an instrumental analysis (taste sensor method). The taste-stimulating effects of bovine and porcine gelatin were also evaluated. The threshold value of astringency of WPI, PWP, and aPWP was 1.5, 1.0, and 0.7 mg/mL, respectively, whereas the gelatins did not give definite astringency. It was confirmed by the scalar scoring method that the astringency of these proteins increased with the increase in protein concentration, and these proteins elicited strong astringency at 10 mg/mL under acidic conditions. On the other hand, the astringency was not elicited at pH 3.5 by 2 types of gelatin. A taste sensor gave specific values for whey proteins at pH 3.5, which corresponded well to those obtained by the sensory analysis. Elicitation of astringency induced by whey protein under acidic conditions would be caused by aggregation and precipitation of protein molecules in the mouth.     

Roles of charge interactions on astringency of whey proteins at low pH

Whey proteins are a major ingredient in sports drink and functional beverages. At low pH, whey proteins are astringent, which may be undesirable in some applications. Understanding the astringency mechanism of whey proteins at low pH could lead to developing ways to minimize the astringency. This study compared the astringency of β-lactoglobulin (β-LG) at low pH with phosphate buffer controls having the same amount of phosphate and at similar pH. Results showed that β-LG samples were more astringent than phosphate buffers, indicating that astringency was not caused by acid alone and that proteins contribute to astringency. When comparing among various whey protein isolates (WPI) and lactoferrin at pH 3.5, 4.5, and 7.0, lactoferrin was astringent at pH 7.0 where no acid was added. In contrast, astringency of all WPI decreased at pH 7.0. This can be explained by lactoferrin remaining positively charged at pH 7.0 and able to interact with negatively charged saliva proteins, whereas the negatively charged WPI would not interact. Charge interactions were further supported by β-LG or lactoferrin and salivary proteins precipitating when mixed at conditions where β-LG, lactoferrin, or saliva themselves did not precipitate. It can be concluded that interactions between positively charged whey proteins and salivary proteins play a role in astringency of proteins at low pH.     

Preference Mapping of Lemon Lime Carbonated Beverages with Regular and Diet Beverage Consumers

The drivers of liking of lemon‐lime carbonated beverages were investigated with regular and diet beverage consumers. Ten beverages were selected from a category survey of commercial beverages using a D‐optimal procedure. Beverages were subjected to consumer testing (n = 101 regular beverage consumers, n = 100 diet beverage consumers). Segmentation of consumers was performed on overall liking scores followed by external preference mapping of selected samples. Diet beverage consumers liked 2 diet beverages more than regular beverage consumers. There were no differences in the overall liking scores between diet and regular beverage consumers for other products except for a sparkling beverage sweetened with juice which was more liked by regular beverage consumers. Three subtle but distinct consumer preference clusters were identified. Two segments had evenly distributed diet and regular beverage consumers but one segment had a greater percentage of regular beverage consumers (P < 0.05). The 3 preference segments were named: cluster 1 (C1) sweet taste and carbonation mouthfeel lovers, cluster 2 (C2) carbonation mouthfeel lovers, sweet and bitter taste acceptors, and cluster 3 (C3) bitter taste avoiders, mouthfeel and sweet taste lovers. User status (diet or regular beverage consumers) did not have a large impact on carbonated beverage liking. Instead, mouthfeel attributes were major drivers of liking when these beverages were tested in a blind tasting. Practical Application : Preference mapping of lemon‐lime carbonated beverage with diet and regular beverage consumers allowed the determination of drivers of liking of both populations. The understanding of how mouthfeel attributes, aromatics, and basic tastes impact liking or disliking of products was achieved. Preference drivers established in this study provide product developers of carbonated lemon‐lime beverages with additional information to develop beverages that may be suitable for different groups of consumers.     

Mouthfeel Detection Threshold and Instrumental Viscosity of Sucrose and High Fructose Corn Syrup Solutions

ABSTRACT:  Significant mouthfeel differences between diet and regular cola carbonated beverages have been reported; however, the underlying cause of those differences is not well understood. One avenue explored here is the connection between mouthfeel differences and mouthfeel thresholds of model solutions containing sweeteners used in regular carbonated beverages. The objectives of this research were to (1) determine individual and group mouthfeel detection thresholds of sucrose and high fructose corn syrup (HFCS) solutions while suppressing sweet taste; (2) relate individual and group thresholds to viscosity and number of sweetener molecules in solution; and (3) measure and compare the viscosities of commercial carbonated beverages to the viscosities of sucrose and HFCS solutions formulated to the concentrations of individual and group thresholds. The R-index measure by the rating method was used by 21 panelists to evaluate the thickness difference of sucrose and HFCS solutions compared to water using Gymnema sylvestre tea to supress sweet taste. The group mouthfeel detection threshold for sucrose was 16.78%± 8.72% (g/100 mL) and for HFCS was 11.48%± 8.67% (g/100 mL). The average viscosity of regular carbonated beverages is within the viscosity range associated with the group mouthfeel threshold concentrations of sucrose and HFCS solutions, but the average viscosity of diet carbonated beverages is lower than the viscosity range associated with the group mouthfeel detection threshold concentrations of sucrose and HFCS solutions. This research implies that consumers are sensitive enough to detect mouthfeel differences between diet and regular carbonated beverages, albeit the instrumental viscosity difference being small (0.527 mPa ⋅ s).     

Identifying Key Attributes for Protein Beverages

This study identified key attributes of protein beverages and evaluated effects of priming on liking of protein beverages. An adaptive choice‐based conjoint study was conducted along with Kano analysis to gain insight on protein beverage consumers (n = 432). Attributes evaluated included label claim, protein type, amount of protein, carbohydrates, sweeteners, and metabolic benefits. Utility scores for levels and importance scores for attributes were determined. Subsequently, two pairs of clear acidic whey protein beverages were manufactured that differed by age of protein source or the amount of whey protein per serving. Beverages were evaluated by 151 consumers on two occasions with or without priming statements. One priming statement declared “great flavor,” the other priming statement declared 20 g protein per serving. A two way analysis of variance was applied to discern the role of each priming statement. The most important attribute for protein beverages was sweetener type, followed by amount of protein, followed by type of protein followed by label claim. Beverages with whey protein, naturally sweetened, reduced sugar and ≥15 g protein per serving were most desired. Three consumer clusters were identified, differentiated by their preferences for protein type, sweetener and amount of protein. Priming statements positively impacted concept liking (P < 0.05) but had no effect on overall liking (P > 0.05). Consistent with trained panel profiles of increased cardboard flavor with higher protein content, consumers liked beverages with 10 g protein more than beverages with 20 g protein (6.8 compared with 5.7, P < 0.05). Protein beverages must have desirable flavor for wide consumer appeal.     

Interactions between whey proteins and salivary proteins as related to astringency of whey protein beverages at low pH

Whey protein beverages have been shown to be astringent at low pH. In the present study, the interactions between model whey proteins (β-lactoglobulin and lactoferrin) and human saliva in the pH range from 7 to 2 were investigated using particle size, turbidity, and ζ-potential measurements and sodium dodecyl sulfate-PAGE. The correlation between the sensory results of astringency and the physicochemical data was discussed. Strong interactions between β-lactoglobulin and salivary proteins led to an increase in the particle size and turbidity of mixtures of both unheated and heated β-lactoglobulin and human saliva at pH ∼3.4. However, the large particle size and high turbidity that occurred at pH 2.0 were the result of aggregation of human salivary proteins. The intense astringency in whey protein beverages may result from these increases in particle size and turbidity at these pH values and from the aggregation and precipitation of human salivary proteins alone at pH <3.0. The involvement of salivary proteins in the interaction is a key factor in the perception of astringency in whey protein beverages. At any pH, the increases in particle size and turbidity were much smaller in mixtures of lactoferrin and saliva, which suggests that aggregation and precipitation may not be the only mechanism linked to the perception of astringency in whey protein.     

Formulation of apple juice beverages containing whey protein isolate or whey protein hydrolysate based on sensory and physicochemical analysis

Whey protein isolate (WPI) or its bioactive hydrolysate (WPH) was mixed with apple juice along with sweetener, obtaining a series of beverages with various pH values. Sedimentation of WPI‐apple juice and WPH‐apple juice beverages was inhibited at pH values of 3.15 and 3.47, respectively. The higher the whey protein content, the more undesirable was the taste of samples. A clearer appearance with smaller particle size was obtained with WPH‐apple juice formulations compared to WPI‐apple juice formulations at pH values closer to the pI of the whey proteins. Intrinsic viscosity measurements revealed the weaker associations of peptides compared with protein molecules.     

Color Halo/Horns and Halo-Attribute Dumping Effects within Descriptive Analysis of Carbonated Beverages

ABSTRACT:  Training panelists to focus on and evaluate a specific set of attributes is difficult. While every attempt is made to eliminate bias, such as methodology, panel influence, and product differences, unknown halo/horns effects may still influence the data collected. The objectives of this research were to (1) determine if a halo/horns effect of color exists in evaluating commercial cola and lemon/lime flavored carbonated beverages, and (2) determine if a halo-attribute dumping effect on mouthfeel attributes exists by aroma, aroma-by-mouth, taste, and afterfeel attributes. Ten panelists were trained to describe aroma, aroma-by-mouth, mouthfeel, taste, and afterfeel attributes of carbonated beverages. Each of the 6 carbonated beverages was evaluated by 3 treatments: (1) as is , (2) mix no color , and (3) mix with color . In the 1st set of product evaluations, all products were evaluated for mouthfeel attributes alone. In the 2nd of product evaluations, all products were evaluated for aroma, aroma-by-mouth, mouthfeel, taste, and afterfeel attributes. Color halo/horns effects were shown on mouthfeel intensity scores of lemon/lime carbonated beverages when caramel color was added. Adding caramel color significantly increased (halo effect) perceived body and mouthcoating and significantly decreased (horns effect) bite, burn, numbing, and carbonation attributes. A halo-attribute dumping effect was observed when mouthfeel attributes were rated exclusively compared to when other attributes in the modalities of aroma, aroma-by-mouth, taste, and afterfeel were rated in addition to mouthfeel attributes. Perceived intensities of bite, burn, numbing, and astringent attributes significantly increased (halo-attribute dumping) when rated alone compared to when all attributes were rated.     

Consumer acceptance of natural sweeteners in protein beverages

Protein beverage consumption by Americans has increased in recent years. Coupled with this increased consumption is an interest in natural sweeteners. The objective of this study was to evaluate the sensory properties of naturally sweetened ready-to-mix (RTM) whey protein beverages using 3 temporal methods and to formulate a natural noncaloric sweetener blend that could be added to RTM protein beverages to provide sweetness while still appealing in flavor to consumers. Iso-sweet concentrations of sweeteners (sucralose, sucrose, fructose, stevia, monk fruit) in RTM vanilla whey protein beverages (25 g of protein/360 mL of water) were established using magnitude estimation scaling and 2-alternative forced-choice testing. Temporal sensory profiling was then conducted on each beverage by a trained panel using time intensity, temporal dominance of sensations, and temporal check-all-that-apply. These findings were used to formulate natural sweetener blends that closely matched the temporality of sucrose-sweetened RTM vanilla protein beverages for consumer testing. One sugar-free blend (25% stevia/75% monk fruit) and 1 reduced-sugar blend (25% stevia/25% monk fruit/50% fructose) were selected for consumer testing (n = 150 consumers) in addition to 3 control RTM beverages containing sucralose, stevia, or monk fruit. Two distinct consumer clusters were identified. The label-conscious segment of consumers preferred beverages sweetened with natural blends when primed. The flavor-driven segment of consumers conceptually preferred naturally sweetened beverages but preferred sucralose-sweetened beverages when primed. An all-natural label claim was most preferred across all consumers. Application of these findings to commercially produced RTM protein beverages aids in the development of naturally sweetened protein beverages with reduced calories and desirable sensory properties and highlights the importance of label claims to consumers overall but to a label-conscious segment of consumers in particular.     

Consumer acceptance measurement focusing on a specified sensory attribute of products: Can the attribute-specified degree of satisfaction-difference (DOSD) method replace hedonic scaling?

A specific attribute can play an important role in determining consumers’ perceived quality and acceptance of a product. Kim, van Hout, Dessirier, and Lee (2018) proposed a new affective method, the degree of satisfaction-difference (DOSD) method, to study consumer acceptance in terms of overall satisfaction with products. In the present study, this DOSD method was further developed to assess satisfaction for a specified attribute of products rather than overall satisfaction, and this modification is referred to as the attribute-specified DOSD method. To test its applicability, 11 bouillon products (including a reference product) varying in viscosity were used as stimuli. Satisfaction with the perceived mouthfeel thickness, which is a viscosity-related sensory attribute, was evaluated with the attribute-specified DOSD method and with a 10-point category scale for overall liking as the control method. Two groups of consumers performed either the attribute-specified DOSD method or hedonic scaling over two repeated sessions. Results showed that the satisfaction patterns of the attribute-specified DOSD method were similar to those of the hedonic scaling across products, confirming that the mouthfeel thickness was a determinant of consumer acceptance for bouillon products. Examining the test reliability in terms of consistency of consumers’ responses for the same stimulus in different sessions, both groups showed consistent results. The subjects who performed the attribute-specified DOSD method were also segmented based on the degree of satisfaction with the reference product. Here, each consumer sensory segment showed different patterns on satisfaction with other test products. These findings demonstrate the potential of the attribute-specified DOSD method for measuring the consumer responses to the level/quality of an important attribute/dimension and highlight its usefulness for consumer sensory segmentation.     

Could cider aroma modify cider mouthfeel properties?

The objective of this work was to evaluate whether aroma–taste interactions could occur in cider due to cognitive interactions such as a dumping effect or a congruency phenomenon. Sixteen French ciders were selected with different organoleptic characteristics. Three different tasting conditions were compared in order to evaluate the presence of aroma interactions with taste. A trained panel was first asked to assess ciders, with and without a nose clip, on four attributes: sweetness, sourness, bitterness and astringency. Secondly, they had to score the same four attributes with seven aroma attributes added. It was shown that the perception of sweetness and astringency was modified in the presence of aroma. Ciders with fruity and caramel aromatic notes were perceived sweeter contrary to ciders with hay, animal and earthy notes, which were perceived less sweet. Moreover, the aroma interaction with sweetness was sugar concentration-dependent. It occurred only in cider containing around 40 g/L of sugar. Finally, ciders were perceived more astringent when tasted without wearing a nose clip.     

Preference Mapping of Soymilk with Different U.S. Consumers

This study determined and compared drivers of liking for unflavored soymilk with different U.S. consumer groups. A highly trained panel documented appearance, mouthfeel and flavor attributes of 26 commercial soymilks. Twelve representative soymilks were then selected for evaluation by consumers from 3 age/cultural categories (n = 75 each category; Caucasian/African American females aged 18 to 30 y; Asian females aged 18 to 30 y; Caucasian/African American females aged 40 to 64 y). Consumers evaluated overall liking and liking and intensity of specific attributes. Results were evaluated by analysis of variance, followed by internal and external preference mapping. Age had no effect on overall liking, while ethnicity did (Caucasian/African American compared with Asian; P < 0.05). Caucasians/African Americans differentiated soymilks more than Asians and assigned a wider range of liking scores than Asians (2.1 to 7.2 compared with 4.0 to 6.1). Three consumer clusters were identified. Sweet taste with vanilla/vanillin and sweet aromatic flavors and higher viscosity were preferred by most consumers and differences between consumer clusters were primarily in drivers of dislike. Drivers of dislike were not identified for Cluster 1 consumers while Clusters 2 and 3 consumers (n = 84, n = 80) disliked beany, green/grassy and meaty/brothy flavors and astringency. Cluster 3 (n = 80) consumers scored all soymilks higher in liking (P < 0.05) than Cluster 2 consumers, and were willing to overlook disliked attributes with the addition of sweet taste, whereas the Cluster 2 consumers were not. These findings can be utilized to produce soymilks with attributes that are well liked by target consumers and to tailor attributes for segments of the population that have not yet been accommodated.     

Polyphenol‐rich beverages: insights from sensory and consumer science

BACKGROUND: Reaching a go/no‐go decision on a product concept early in the innovation cycle can save companies significant resources. The current research is situated within this context. Using polyphenol‐rich beverages that were at an early stage in the formulation/optimisation cycle, a number of insights were sought: (1) how acceptable to consumers were these early‐stage formulations; (2) what sensory attributes contributed to consumer liking/disliking; and (3) could the disliked sensory attribute(s) be sufficiently masked within the chosen product format? RESULTS: Beverages were formulated according to a 2 × 4 factorial design where one factor varied the polyphenol source and the other sweetness. While consumer acceptability and purchase probability increased with sucrose concentration, the beverages were of below‐average sensory quality. Bitterness was identified as a key sensory attribute to focus on in future optimisation efforts. CONCLUSION: A number of approaches exist for masking bitterness and there appeared to be little reason why at least some of the beverages could not be improved to achieve high levels of sensory quality and consumer acceptance. Further, it is suggested that disclosing information about health properties of these polyphenol‐rich beverages during consumer testing may further enhance their appeal to consumers. Copyright © 2009 Society of Chemical Industry     

Properties of whey protein isolates extruded under acidic and alkaline conditions

Whey proteins have wide acceptance and use in many products due to their beneficial nutritional properties. To further increase the amount of whey protein isolates (WPI) that may be added to products such as extruded snacks and meats, texturization of WPI is necessary. Texturization changes the folding of globular proteins to improve interaction with other ingredients and create new functional ingredients. In this study, WPI pastes (60% solids) were extruded in a twin-screw extruder at 100 degrees C with 4 pH-adjusted water streams: acidic (pH 2.0 +/- 0.2) and alkaline (pH 12.4 +/- 0.4) streams from 2 N HCl and 2 N NaOH, respectively, and acidic (pH 2.5 +/- 0.2) and alkaline (pH 11.5 +/- 0.4) electrolyzed water streams; these were compared with WPI extruded with deionized water. The effects of water acidity on WPI solubility at pH 7, color, microstructure, Rapid Visco Analyzer pasting properties, and physical structure were determined. Alkaline conditions increased insolubility caused yellowing and increased pasting properties significantly. Acidic conditions increased solubility and decreased WPI pasting properties. Subtle structural changes occurred under acidic conditions, but were more pronounced under alkaline conditions. Overall, alkaline conditions increased denaturation in the extruded WPI resulting in stringy texturized WPI products, which could be used in meat applications.