Sensory characteristics of human milk: Association between mothers' diet and milk for bitter taste

It is unknown how consumption of bitter foods and beverages in the maternal diet influences sensory properties of fresh human milk. The aims of this study were (1) to determine the sensory characteristics of fresh human fore and hind milk, (2) to establish relationships between sensory properties and composition of fresh human milk, and (3) to assess the relationship between bitterness of the maternal diet and human milk. Twenty-two lactating mothers generated sensory terms to describe perception of their milk and received training on sensory attribute intensity rating. Mothers kept a 24-h food diary followed by a sensory self-assessment of their fore and hind milks. The odor of human fresh milk was described as neutral, creamy, and sweet, taste as sweet and bitter, and mouthfeel as thin, watery, smooth, and fatty. Sweetness was equivalent to 1.53 g of sucrose/100 mL and was not significantly different between fore and hind milk. Fore milk was significantly less creamy, less fatty, thinner, more watery, and lower in vanilla flavor intensity than hind milk. Carbohydrate content of human milk was positively correlated with sweetness and glutamic acid content with umami. The bitterness of the diet consumed 24 h before lactation was moderately positively correlated with bitterness of fore milk, but not hind milk. We conclude that the consumption of bitter foods may influence the bitterness of human fore milk, which may be another way for?breastfed children to learn to accept bitter vegetables and, hence, develop healthier food preferences.     

Interactions among salty, sour and bitter compounds

The human gustatory system is capable of responding to and processing the taste of solitary compounds in water. However, the taste system rarely contacts solitary compounds outside the laboratory and has surely evolved to process complex mixtures of sapid chemicals, such as occur in virtually all foods. This review will focus primarily on the lesser-studied interactions between pairs of salty, sour and bitter compounds. Pair-wise interactions among these three taste qualities should be of interest because they constitute a significant proportion (∼30–50%) of possible binary taste interactions. In general, salts and acids enhance each other at moderate concentrations but suppress each other at higher concentrations. Bitter compounds and acids can either enhance or suppress each other depending on the concentrations, the food stimuli and the experimental methods involved. Sodium salts and bitter compounds generally interact so that bitterness is suppressed to some variable degree and the saltiness is unaffected. As will be described below, there are exceptions to all of these generalities.     

The role of sour and bitter perception in liking,familiarity and choice for phenol-rich plant-based foods

Among factors influencing food preferences and choices, individual differences in taste perception play a key role in defining eating behaviour. In particular, sour and bitter responsiveness could be associated with the acceptance and the consumption of phenol-rich plant-based foods recommended for a healthy diet. The aim of this study was to investigate, in a large population sample, the associations among sour and bitter responsiveness and liking, familiarity and choice for plant-based foods characterized by these target tastes. Adults aged 18 to 60 years (n = 1198; 58% women) were tested for their sour and bitter responsiveness both in water solutions and in food models (pear juice-based beverages modified in citric acid content to induce different levels of sourness: 0.5, 2.0, 4.0 and 8.0 g/kg; chocolate pudding samples modified in sucrose content to induce different levels of bitterness: 38, 83, 119, 233 g/kg). Familiarity, stated liking and choice for fruit juices and vegetables varying for sour/bitter taste (high in bitter/sour taste: e.g. grapefruit juice and cauliflower; low in bitter/sour taste: e.g. zucchini and pineapple juice) were measured. Results showed a significant positive correlation between bitter and sour taste perception in water solutions and model foods, as well as a positive correlation between the perceived intensity of the two taste stimuli. Subjects characterized by high responsiveness to the two target stimuli were found to give lower liking scores to foods characterized by sour/bitter tastes and tended to choose less sour/bitter foods compared to less responsive subjects.Thus, food choice for phenol rich plant-based products could be associated with a reduced responsiveness to bitter and sour tastes and a consequent higher acceptance of food products characterized by these taste qualities.     

Optimizing the orosensory properties of model functional beverages: the influence of novel sweeteners, odorants, bitter blockers, and their mixtures on (+)-catechin

This paper is dedicated to the memory of colleague and friend, Dr. Samson Agboola, who recently passed away. Abstract: The use of flavor‐modifying strategies are important to improving the sensory profile of some excessively bitter and astringent functional ingredients, such as (+)‐catechin (CAT). Two bitter blockers (ß‐cyclodextrin [CYCLO], homoeriodictyol sodium salt [HED]), two sweeteners (sucrose [SUC], rebaudioside A [REB]), and two odorants (vanillin [VAN], black tea aroma [TEA]) were assessed for their efficacy at modifying the bitterness and astringency of CAT in model aqueous solutions. The intensity of oral sensations elicited by CAT was determined in duplicate in binary, ternary, and quaternary mixtures of these stimuli by a trained panel (n= 15) using a 15 cm visual analogue scale. Overall, bitterness and astringency were most effectively reduced by ternary solutions containing CYCLO + REB or CYCLO + SUC (68%, 60%, and 45%, 43% for bitterness and astringency, respectively). Odorants were not effective at modifying the bitterness or astringency of CAT. We conclude that the use of select bitter blockers and sweeteners may be of value in optimizing the flavor and acceptance of functional food and beverages fortified with phenolic compounds. Practical Application: (+)‐Catechin is a bitter‐tasting plant‐derived health‐promoting phenolic compound of interest to functional food and beverage manufacturers. We investigated the efficacy of bitter blockers, plant‐based sweeteners, and odorants in decreasing the bitterness and astringency elicited by (+)‐catechin. Some of these additives, both alone and in combination, reduced bitterness and astringency, and may therefore assist in optimizing the flavor and consumer acceptance of some phenolic‐based functional foods and beverages.     

苦味机理及苦味物质的研究概况

苦味是一种分布广泛、阈值极低的味感,而消费者往往拒食苦味食物,但苦味物质在食品风味和生理调节方面具有重要作用。简要论述了苦味呈味机理、几种苦味物质的功能特性以及苦味抑制剂方面的研究进展。     

The applications and future implications of bitterness reduction and inhibition in food products

Numerous food and beverage products, bulking agents, and pharmaceuticals have pleasant as well as unpleasant bitter-tasting components in their taste profile. In numerous cases, the bitter taste modality is an undesirable trait of the product. Bitter characteristics found in some food systems have been removed or diminished by various known processes, but no universally applicable bitter inhibitor has ever been recognized. Some indications point to a receptor-mediated phenomenon for sweetness and bitterness. Research on sweet compounds has led to knowledge of sweetness inhibitors and could ultimately lead to bitterness inhibitors. To facilitate efforts to rationally design a universal bitter inhibitor or cocktail of such, a review of the bitter taste phenomena and known methods of bitterness reduction and inhibition have been compiled.     

Could hop-derived bitter compounds improve glucose homeostasis by stimulating the secretion of GLP-1?

Hops (Humulus lupulus L.) is by far the greatest contributors to the bitter property of beer. Over the past years, a large body of evidence demonstrated the presence of taste receptors in different locations of the oral cavity. In addition to the taste buds of the tongue, cells expressing these receptors have been identified in olfactory bulbs, respiratory and gastrointestinal tract. In the gut, the attention was mainly directed to sweet Taste Receptor (T1R) and bitter Taste Receptor (T2R) receptors. In particular, T2R has shown to modulate secretion of different gut hormones, mainly Glucagon-like Peptide 1 (GLP-1), which are involved in the regulation of glucose homeostasis and the control of gut motility, thereby increasing the sense of satiety. Scientific interest in the activity of bitter taste receptors emerges because of their wide distribution in the human species and the large range of natural substances that interact with them. Beer, whose alcohol content is lower than in other common alcoholic beverages, contains a considerable amount of bitter compounds and current scientific evidence shows a direct effect of beer compounds on glucose homeostasis. The purpose of this paper is to review the available literature data in order to substantiate the novel hypothesis of a possible direct effect of hop-derived bitter compounds on secretion of GLP-1, through the activation of T2R, with consequent improvement of glucose homeostasis.     

新地奥明在抑制柑橘类果汁苦味中的应用

柠碱和柚苷是柑橘汁和柑橘类果汁中的主要苦味成分,本文综述了苦味形成机理和添加新地奥明(Neodiosmin)对柑橘类果汁的苦味成分的抑制作用。     

Determination of taste-active compounds of a bitter Camembert cheese by omission tests

The taste-active compounds of a Camembert cheese selected for its intense bitterness defect were investigated. The water-soluble fraction (WSE) was extracted with pure water and fractionated by successive tangential ultrafiltrations and nanofiltration. The physicochemical assessment of these fractions led to the construction of a model WSE which was compared by sensory evaluation to the crude water-soluble extract, using a panel of 16 trained tasters. As no significant difference was perceived, this model WSE was then used directly or mixed with other cheese components for omission tests. Among the main taste characteristics of the WSE (salty, sour, umami and bitter), bitterness was found to be due to small peptides whose mass distribution was obtained by RPHPLC-MS (400-3000 Da) and whose taste properties are discussed.     

Investigation of bitterness in carrots (Daucus carota L.) based on quantitative chemical and sensory analyses

Bitterness is considered as an undesirable taste of carrots. Quantitative chemical analysis of potential bitter compounds of different carrot genotypes was combined with sensory analysis in order to identify key compounds likely to be responsible for the bitterness of carrots. Eight carrot genotypes (‘Bolero’, ‘Mello Yello’, ‘Nairobi’, ‘Tornado’, ‘Purple Haze’, ‘Line 1’, ‘Line 2’, and ‘Line 3’) representing extremes in sensory-perceived odour, flavour, and taste. Potential bitter compounds like polyacetylenes, isocoumarins and phenolic acids were quantified in the peel and the corresponding peeled carrot, and their contribution to bitterness in raw carrots was analysed by sensory profiling using multivariate data analysis. Falcarindiol and a di-caffeic acid derivative were highly related to bitterness in contrast to falcarinol and other potential bitter compounds. Falcarindiol and the di-caffeic acid derivative were primarily present in the peel whereas falcarinol was almost evenly distributed in the root. Investigation of bitterness revealed that high sugar content to some extent could mask the bitter perception of carrots. As falcarinol is the most bioactive of the carrot polyacetylenes the results of the present study indicate that there is a basis for improving the health effects of raw carrots without affecting sensory quality.     

Wine Expertise Predicts Taste Phenotype

Taste phenotypes have long been studied in relation to alcohol intake, dependence, and family history, with contradictory findings. However, on balance - with appropriate caveats about populations tested, outcomes measured and psychophysical methods used - an association between variation in taste responsiveness and some alcohol behaviors is supported. Recent work suggests super-tasting (operationalized via propylthiouracil (PROP) bitterness) not only associates with heightened response but also with more acute discrimination between stimuli. Here, we explore relationships between food and beverage adventurousness and taste phenotype. A convenience sample of wine drinkers (n=330) were recruited in Ontario and phenotyped for PROP bitterness via filter paper disk. They also filled out a short questionnaire regarding willingness to try new foods, alcoholic beverages and wines as well as level of wine involvement, which was used to classify them as a wine expert (n=110) or wine consumer (n=220). In univariate logisitic models, food adventurousness predicted trying new wines and beverages but not expertise. Likewise, wine expertise predicted willingness to try new wines and beverages but not foods. In separate multivariate logistic models, willingness to try new wines and beverages was predicted by expertise and food adventurousness but not PROP. However, mean PROP bitterness was higher among wine experts than wine consumers, and the conditional distribution functions differed between experts and consumers. In contrast, PROP means and distributions did not differ with food adventurousness. These data suggest individuals may self-select for specific professions based on sensory ability (i.e., an active gene-environment correlation) but phenotype does not explain willingness to try new stimuli.     

The efficacy of bitter blockers on health-relevant bitterants

Current strategies for decreasing the bitterness of conventional foods often involve the addition of sucrose and sodium chloride. However this has limited application with functional foods, as they are health promoting, and other approaches are required. This study assesses the efficacy of high and low concentrations of five bitter inhibiting compounds [β-cyclodextrin (β-CYCLO), homoeriodictyol sodium salt (HED), zinc sulphate monohydrate (ZnSO₄), magnesium sulphate (MgSO₄), carboxymethylcellulose sodium salt (CMC)] on the perceived bitterness of high and low concentrations of (+)-catechin and caffeine – two ingredients used in functional food formulations. Intensity ratings (bitterness, sourness, saltiness, sweetness, savoriness, astringency, ‘other’) of bitterant-bitter blocker binary solutions were collected from a panel of twelve, in duplicate, using a 15 cm line scale. Overall, β-CYCLO and HED were the most effective blockers at decreasing the bitterness of (+)-catechin, while the bitterness of caffeine was reduced most effectively by HED. Results also demonstrate that the bitter reducing capacity of these blockers is bitterant dependent. In general, these bitter blockers elicit minimum side tastes and sensations, although astringency and viscosity intensities are increased under some conditions. We conclude that some bitter blockers show considerable potential for decreasing the bitterness of phenols and caffeine in functional food formulations.     

Sensory Quality of Functional Beverages: Bitterness Perception and Bitter Masking of Olive Leaf Extract Fortified Fruit Smoothies

Abstract: Olive leaf extract (OLE) contains high amounts of oleuropein and hydroxytyrosol. The antioxidant capacity of these polyphenols makes OLE a promising ingredient for functional food. OLE causes very strong bitterness perception and can therefore only be formulated in low concentrations. In this research, bitter detection and recognition thresholds of OLE-fortified fruit smoothies were determined by a trained sensory panel (n = 11). Masking of the OLE's bitter taste was investigated with addition of sodium cyclamate, sodium chloride, and sucrose by means of a standardized ranking method and a scale test. Detection (5.78 mg/100 g) and recognition thresholds (8.05 mg/100 g) of OLE polyphenols confirmed the low formulation limits when bitterness was not masked by other substances. At higher polyphenol levels of 20 mg/100 g, sodium cyclamate and sucrose were able to reduce bitter taste perception by 39.9% and 24.9%, respectively, whereas sodium chloride could not effectively mask bitterness. Practical Application: Development of functional food poses new challenges for the food industry. A major problem in this field is the high bitterness of natural polyphenol-containing extracts with potential health benefits. This research was conducted to understand the sensory impact of olive leaf extract (OLE), a novel food ingredient with very bitter taste. In product development, the data of this research can be considered for formulation limits and the general sensory quality of OLE-fortified food and beverages.     

Bitterness of cassava: Identification of a new apiosyl glucoside and other compounds that affect its bitter taste

Compounds extracted by methanol from cassava parenchyma and cortex have been separated on a preparative HPLC column and identified by ¹H and ¹³C NMR spectroscopy. A new compound isopropyl-β-D -apiofuranosyl-(1 → 6)-β-D -glucopyranoside (IAG, structure I ) has been found as well as small amounts of phenylalanine and tryptophan. The composition of another HPLC fraction has not been elucidated. The amounts of the identified compounds and of linamarin, lotaustralin, citrate, malate and the various sugars present in cassava have been determined by HPLC methods. The threshold levels of bitterness of aqueous solutions of linamarin, lotaustralin and IAG, have been determined and together with published data on L -phenylalanine and L -tryptophan have allowed our evaluation of their contributions to the bitterness of cassava. Linamarin is the sole contributor in the parenchyma but (with two cultivars out of six studied) IAG contributes more to the bitterness of the cortex than does linamarin. The perception of bitterness of linamarin solutions is confounded in the presence of neutral citrate and malate which have a sour taste. These modify the taste of cassava tubers. There are many compounds that contribute to the taste of cassava tubers, hence it is not surprising that the bitterness of cassava is not always correlated positively with the cyanide potential.     

Identification of bitter compounds in whole wheat bread

Bitterness in whole wheat bread can negatively influence product acceptability and consumption. The overall goal of this project was to identify the main bitter compounds in a commercial whole wheat bread product. Sensory-guided fractionation of the crust (most bitter portion of the bread sample) utilising liquid–liquid extraction, solid-phase extraction, ultra-filtration and 2-D offline RPLC revealed multiple bitter compounds existed. The compounds with the highest bitterness intensities were selected and structurally elucidated based on accurate mass-TOF, MS/MS, 1D and 2D NMR spectroscopy. Eight bitter compounds were identified: Acortatarins A, Acortatarins C, 5-(hydroxymethyl)furfural(HMF), 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (DDMP), N-(1-deoxy-d-fructos-1-yl)-l-tryptophan (ARP), Tryptophol (TRO), 2-(2-formyl-5-(hydroxymethyl-1H-pyrrole-1-yl)butanoic acid (PBA) and Tryptophan (TRP). Based on the structures of these compounds, two main mechanisms of bitterness generation in wheat bread were supported, fermentation and Maillard pathways.     

Assessing the authenticity of absinthe using sensory evaluation and HPTLC analysis of the bitter principle absinthin

Absinthe is a spirit drink that owes its bitter taste to substances found in the wormwood plant (Artemisia absinthium L.). The prohibition against absinthe has recently been annulled, giving rise to numerous inferior products that lack the organoleptic characteristics of wormwood. The monoterpene thujone, which occurs in the essential oil fraction of wormwood, has previously been used as a marker substance to confirm the authenticity of absinthe. However, thujone possesses adverse toxicological properties; thus modern procedures have been developed to remove this substance from absinthe. In addition, thujone-free wormwood is also available from certain cultivation areas.This study is the first to use sensory evaluation of wormwood taste, louche effect, and bitterness in order to classify absinthes. This study also introduces a simple, fast, and sensitive procedure using high-performance thin-layer chromatography (HPTLC) to assess the levels of absinthin, a characteristic bitter substance found in wormwood. Results of this study demonstrate a strong correlation between the concentration of wormwood and the organoleptically determined bitterness value (R = 0.75).     

A review of the associations between single nucleotide polymorphisms in taste receptors,eating behaviors,and health

Food preferences and dietary habits are heavily influenced by taste perception. There is growing interest in characterizing taste preferences based on genetic variation. Genetic differences in the ability to perceive key tastes may impact eating behavior and nutritional intake. Therefore, increased understanding of taste biology and genetics may lead to new personalized strategies, which may prevent or influence the trajectory of chronic disease risk. Recent advances show that single nucleotide polymorphisms (SNPs) in the CD36 fat taste receptor are linked to differences in fat perception, fat preference, and chronic-disease biomarkers. Genetic variation in the sweet taste receptor T1R2 has been shown to alter sweet taste preferences, eating behaviors, and risk of dental caries. Polymorphisms in the bitter taste receptor T2R38 have been shown to influence taste for brassica vegetables. Individuals that intensely taste the bitterness of brassica vegetables (“supertasters”) may avoid vegetable consumption and compensate by increasing their consumption of sweet and fatty foods, which may increase risk for chronic disease. Emerging evidence also suggests that the role of genetics in taste perception may be more impactful in children due to the lack of cultural influence compared to adults. This review examines the current knowledge of SNPs in taste receptors associated with fat, sweet, bitter, umami, and salt taste modalities and their contributions to food preferences, and chronic disease. Overall, these SNPs demonstrate the potential to influence food preferences and consequently health.     

香气增甜的作用机制及评价方法研究进展

食品减糖比较常见的方法是使用非营养性甜味剂,但非营养性甜味剂会带来不受欢迎的苦味或金属味及安全风险。研究表明,在某些食物中加入香气物质可以增强人体对食品的甜味感知,即利用香气增甜作用达到食品减糖效果。从气味物质种类、甜味剂浓度2个方面总结了对香气增甜作用有重要影响的因素;从正鼻途径和后鼻途径的嗅觉感受机制、脑神经及味觉感受机制、心理感受机制3个方面阐述了香气增甜的作用机制,总结了分子模拟在分析甜味剂与味觉受体结合、释放过程的应用;归纳了评价香气增甜作用大小的感官分析方法,并比较描述性感官分析法、时间强度法和感觉时间支配分析法3种感官分析方法的差异性;对香气增甜作用在食品工业中的应用现状进行了汇总;对香气增甜研究方向以及分析气味增强味觉作用机制的方法提出展望,以期为香气减糖的研究提供新思路。     

Personality traits and bitterness perception influence the liking and intake of pale ale style beers

Bitterness is classically considered undesirable in foods and beverages. Yet, widespread commercial success of beers (like Bitters in the UK or IPAs in the US) indicate bitterness is desirable for some consumers. Here, we tested whether personality traits influence beer liking and intake. Under laboratory conditions, beer consumers (n = 109) rated liking and intensity of 2 pale ales and a lager, and intensity of two bitter solutions (quinine, Tetralone®). Participants also completed intake and personality questionnaires (Sensation Seeking, Sensitivity to Punishment and Reward, and Food Involvement). A liking ratio for each beer was calculated from each participant’s liking for that specific beer and their total liking for all beers. Participants were classified as weekly, monthly, or yearly pale ale consumers using intake data. Using intensity ratings, personality measures, and other parameters, hierarchical linear regression was used to predict liking ratios, and logistic regression was used to predict beer intake frequency. A significant interaction between Sensation Seeking and quinine bitterness (p = 0.03) was found for the liking ratio of a pale ale. The interaction revealed liking of the pale ale increased with Sensation Seeking but only if quinine bitterness was also high. Intake models showed increased odds of frequent pale ale intake with greater quinine bitterness and lower liking for lager beer. These data suggest liking and intake of pale ales is positively related to Sensation Seeking and bitter taste perception. Contrary to findings in other bitter foods and beverages, the high bitterness found in pale ales may be desirable for some consumers.