Untargeted LC-MS based identification of Rebaudioside A degradation products impacting flavor perception during storage

Untargeted LC-MS flavoromics chemical profiling was used to identify compounds predictive of Rebaudioside A (Reb A) flavor instability in an acidified beverage after 6 weeks at 35 °C. High-quality orthogonal partial least squares analysis models were developed from the chemical data and d' values from tetrad sensory panel testing with good predictive ability. The top four highly predictive compounds were selected and identified as Reb A (negatively correlated) and three Reb A degradation compounds (positively correlated), which included a rearrangement, hydration, and an epoxidation/rearrangement of Reb A, termed compounds 1, 2, and 3, respectively. The concentrations of compounds 1-3 in the aged beverages were determined to be below the sensory recognition threshold values. However, sensory recombination testing of compounds 1-3 as a tertiary mixture revealed a perceivably significant flavor change that was aligned with the aged beverage.

Taste responsiveness of Western chimpanzees (Pan troglodytes verus) to five food-associated saccharides

Using a two-bottle choice test of short duration, we determined taste preference thresholds for sucrose, fructose, glucose, lactose, and maltose in three Western chimpanzees (Pan troglodytes verus). Further, we assessed relative preferences for these five saccharides when presented at equimolar concentrations and determined taste preference difference thresholds for sucrose, that is, the smallest concentration difference at which the chimpanzees display a preference for one of the two options. We found that the chimpanzees significantly preferred concentrations as low as 20 mM sucrose, 40 mM fructose, and 80 mM glucose, lactose, and maltose over tap water. When given a choice between all binary combinations of these five saccharides presented at equimolar concentrations of 100, 200, and 400 mM, respectively, the animals displayed significant preferences for individual saccharides in the following order: sucrose > fructose > glucose = maltose = lactose. The taste difference threshold for sucrose, expressed as Weber ratio (ΔI/I), was 0.3 and 0.4, respectively, at reference concentrations of 100 and 200 mM. The taste sensitivity of the chimpanzees to the five saccharides falls into the same range found in other primate species. Remarkably, their taste preference thresholds are similar, and with two saccharides even identical, to human taste detection thresholds. The pattern of relative taste preferences displayed by the chimpanzees was similar to that found in platyrrhine primates and to the pattern of relative sweetness as reported by humans. Taken together, the results of the present study are in line with the notion that taste sensitivity for food-associated carbohydrates may correlate positively with phylogenetic relatedness. Further, they support the notion that relative preferences for food-associated carbohydrates, but not taste difference thresholds, may correlate with dietary specialization in primates.

Sodium aspartate as a specific enhancer of salty taste perception-sodium aspartate is a possible candidate to decrease excessive intake of dietary salt

The excessive intake of dietary salt is a global issue in health. Attempts have been made to address this issue, including the development of salt substitutes. Yet, none of these substances are currently in wide use, because of their weak saltiness. The purpose of this study was to assess the effects of sodium aspartate (Asp-Na) on salty taste perception using the bullfrog glossopharyngeal nerve response and human sensory tests. When added to the mixture of NaCl and KCl, Asp-Na significantly enhanced the glossopharyngeal nerve response to the mixture by 1.6-fold compared to control. Asp-Na did not enhance the response to NaCl, nor did Asp-Na enhance the response to sour, bitter, or umami stimuli. The optimal concentration for Asp-Na to enhance the salt mixture was 1.7mM. The largest enhancement was induced when NaCl and KCl were mixed at equimolar concentrations. Asp-Na significantly suppressed the glossopharyngeal nerve response to quinine hydrochloride, which suggests that bitterness of KCl is suppressed by Asp-Na. The salty taste enhancing effect of Asp-Na was also confirmed with human sensory tests. The present results suggested that the mixture of NaCl and KCl containing Asp-Na can be used as a salt substitute. In addition to demonstrating that Asp-Na enhanced salt taste responses in an experimental animal and human, our findings provide clues to identify the elusive salty taste receptors.

Comparison of sensory, physiological, personality, and cultural attributes in regular spicy food users and non-users

Some individuals savor spicy foods, while others avoid them. Reasons underlying this range of hedonic responses are unknown. The purpose of this study was to explore the basis for individual differences in preference for spicy foods. Regular spicy food users (n=13) and non-users (n=12) were characterized for selected sensory, physiological, personality, and cultural attributes. Individual differences between users and non-users were primarily related to sensory and cultural attributes (i.e., a higher proportion of users reported consuming spicy foods since childhood and users rated spicy foods as more palatable and were better able to discriminate this burn than non-users). Users and non-users exhibited comparable responsiveness to noxious pressure pain, oral tactile sensitivity, and auditory sensitivity, varying only in responsiveness to oral thermal heat (i.e., users were more sensitive to increases than non-users). Studied personality traits did not vary between users and non-users. These findings suggest that prior experience, rather than physiological adaptation or personality differences, may best predict preference for spicy foods. These findings are of public health interest, given that spicy food consumption is reported to confer weight management and food safety benefits.

Individually Modified Saliva Delivery Changes the Perceived Intensity of Saltiness and Sourness

Individuals vary largely in their salivary flow and composition, and given the importance of saliva on perception of taste, this might influence how the tastant stimuli are perceived. We therefore hypothesise that altering the individual salivary flow rates has an impact on the perceived taste intensity. In this study, we investigated the role of saliva amount on the perceived taste intensity by excluding parotid saliva and adding artificial saliva close to the parotid duct at preset flow rates. Significant decreases in perception with increasing salivary flow rates were observed for citric acid and sodium chloride. This can partially be explained by a dilution effect which is in line with previous studies on detectable concentration differences. However, since the bitterness and sweetness remained unaffected by the salivary flow conditions and the dilution effect was comparable to that of saltiness, further explanation is needed. Furthermore, we investigated whether the suppression of taste intensity in binary mixtures (taste–taste interactions) could possibly be caused by the increased salivary flow rate induced by an additional taste attribute. The results show, however, that suppression of taste intensity in binary mixtures was not affected by the rate of salivation. This was more likely to be explained by psychophysics.

Sensory characteristics and cross-cultural consumer acceptability of Bulgogi (Korean traditional barbecued beef)

Bulgogi (Korean traditional barbecued beef) is the most well-known Korean food to foreigners. There are, however, few studies on its sensory characteristics and consumer acceptability. This study was performed to identify the sensory attributes of Bulgogi samples prepared with different formulation and to compare the consumer acceptability in Korea and the United States. Bulgogi samples were prepared with varying levels of sugar and soy sauce with/without garlic or sesame oil. Descriptive analysis was conducted by 8 trained panelists. In consumer tests, 42 consumers in Seoul, Korea, 53 consumers in Davis (Calif., U.S.A.), and 39 consumers in St. Paul (Minn., U.S.A.) participated. Higher levels of sugar and soy sauce (SSS) significantly increased sweetness, saltiness, MSG taste, and soy sauce odor/flavor compared to the control made with the standard formula (CON). Elimination of sesame oil (ESO) significantly decreased sesame oil odor/flavor and oiliness, but increased green onion flavor. Elimination of garlic (EGC) significantly increased grilled beef odor/flavor, sesame oil odor/flavor, and oiliness, but decreased intensities of all the other attributes except bitterness. The consumers in Korea and the United States rated their overall liking for all samples similarly, preferring SSS to CON, EGC, and ESO. However Korean consumers seemed to detect the differences caused by formulation changes better than the U.S. consumers and these perceived differences seemed to impact the hedonic and the just-about-right ratings. Increase in soy sauce and sugar increased both Korean and the U.S. consumers' acceptability of Bulgogi, whereas eliminating garlic did not influence the consumer acceptability despite of its significant impact on sensory attributes.

PRACTICAL APPLICATION

The food industry is increasingly interested in ethnic foods that satisfy sophisticated appetite of today's consumers. Korean cuisine is recently gaining popularity and perceived as "adventurous and spicy," appealing to researchers and marketers in the food industry worldwide. However, it is not easy to develop a new product based on ethnic cuisine because nonsensory factors, such as food neophobia and openness to new culture, can evoke adverse responses from the consumers. A systematic sensory approach can guide the product development by identifying both sensory and nonsensory factors affecting consumer acceptability. This study investigated sensory attributes of Bulgogi (Korean traditional barbecued beef), one of the most famous Korean foods, and compared consumer acceptability between Korea and the United States. The outcomes of this study, such as flavor profiles, consumer responses, evaluation procedure, and approaches taken for cross-cultural comparison, will provide the food industries with valuable information that will help to develop effective strategies for commercializing ethnic foods including recipe development for Bulgogi marinades.

Same genetic components underlie different measures of sweet taste preference

BACKGROUND

Sweet taste preferences are measured by several often correlated measures.

OBJECTIVE

We examined the relative proportions of genetic and environmental effects on sweet taste preference indicators and their mutual correlations.

DESIGN

A total of 663 female twins (324 complete pairs, 149 monozygous and 175 dizygous pairs) aged 17-80 y rated the liking and intensity of a 20% (wt/vol) sucrose solution, reported the liking and the use-frequency of 6 sweet foods (sweet desserts, sweets, sweet pastry, ice cream, hard candy, and chocolate), and completed a questionnaire on cravings of sweet foods. The estimated contributions of genetic factors, environmental factors shared by a twin pair, and environmental factors unique to each twin individual to the variance and covariance of the traits were obtained with the use of linear structural equation modeling.

RESULTS

Approximately half of the variation in liking for sweet solution and liking and use-frequency of sweet foods (49-53%) was explained by genetic factors, whereas the rest of the variation was due to environmental factors unique to each twin individual. Sweet taste preference-related traits were correlated. Tetravariate modeling showed that the correlation between liking for the sweet solution and liking for sweet foods was due to genetic factors (genetic r = 0.27). Correlations between liking, use-frequency, and craving for sweet foods were due to both genetic and unshared environmental factors.

CONCLUSION

Detailed information on the associations between preference measures is an important intermediate goal in the determination of the genetic components affecting sweet taste preferences.

Taste difference thresholds for sucrose in two species of nonhuman primates

The purpose of this study was to determine taste difference thresholds for sucrose in frugivorous spider monkeys and omnivorous baboons. Using a two-bottle preference test of brief duration, we presented four Ateles geoffroyi and four Papio hamdryas anubis with six different reference concentrations (RCs) of 25, 50, 100, 200, 300, and 400 mM sucrose and tested their ability to discriminate these from lower concentrations of this carbohydrate. The just noticeable differences (JNDs), expressed as Weber ratios (delta/I), were found to range from 0.075-0.25 in the spider monkeys, with a tendency for lower values with higher RCs. In contrast, the baboons showed the reverse trend, with the lowest Weber ratio of 0.10 at the two lowest RCs and higher values of up to 0.25 with the highest RC tested. Thus, the JNDs were found to be generally similar in both species and at least as low as in humans. The results support the assumption that both spider monkeys and baboons may use sweetness as a criterion for food selection. The different patterns of differential sensitivity for sucrose across the range of concentrations tested suggest a correlation between the ability to discriminate between different concentrations of sucrose and the dietary habits of the two species.

Monogeusia for fructose, glucose, sucrose, and maltose

We investigated the ability of subjects to discriminate sugars with a whole-mouth forced-choice paradigm, in which a standard solution was compared with a test solution of varied concentration. Discrimination probabilities were U-shaped functions of test concentration: for 6 subjects and pairwise combinations of fructose, glucose, and sucrose, discriminability always declined to chance over a narrow range of test concentrations. At concentrations < or = 100 mM, maltose was indiscriminable from fructose but discriminable at higher concentrations for 4 subjects. By analogy with the monochromacy of night vision, whereby any two lights are indiscriminable when their relative intensities are suitably adjusted, we call the gustatory indiscriminability of these sugars monogeusia. The simplest account of monogeusia is that all information about the indiscriminable sugars is represented by a single neural signal that varies only in magnitude. The discriminability of maltose from the other sugars at higher concentrations is consistent with the hypothesis that maltose also activates a second gustatory code.