Impact of apple procyanidins on sensory perception in model cider (part 2): Degree of polymerization and interactions with the matrix components

The impact of the degree of polymerization (DP) of procyanidins and its interactions with fructose, acidity and alcohol in a model solution of cider was investigated. Four sensory characteristics (bitterness, astringency, sweetness and sourness) were studied. At 750 mg/L of procyanidins, the DP impacted astringency and bitterness but not sweetness or sourness. The medium DP (tetramer) of apple procyanidins was the most bitter and astringency increased with the DP. The impact of ethanol, fructose and acidity on the four sensory attributes was also examined. These results provide insights into how the components interact to produce the taste of cider.     

基于电子舌的氯吡脲对草莓风味影响的研究

在草莓“甜查理”盛花后一周,喷施清水及4个浓度（2.5、5.0、10、20 mg/L）的氯吡脲,检测由此产生的草莓果实可溶性固形物、总酸、游离氨基酸、单宁等风味营养品质含量,电子舌分析技术检测酸、甜、苦、鲜、咸、涩味、苦味回味、涩味回味等味觉指标,评价氯吡脲的使用及浓度水平对草莓风味营养品质和滋味的影响,并分析电子舌在检测氯吡脲对草莓滋味影响方面运用的优势。结果表明：氯吡脲能够提高草莓果实的可溶性固形物的含量,降低总酸含量,提高固酸比值,降低游离氨基酸种类和游离氨基酸总量;低浓度（2.5、5.0 mg/L）的氯吡脲处理能降低草莓单宁含量,而高浓度（10、20 mg/L）处理会使单宁含量显著升高;电子舌味觉分析结果表明低浓度氯吡脲处理可使草莓甜味增加,酸味降低,但是咸味和鲜味及与其高度相关（相关系数均为0.99）的苦味也相应降低;游离氨基酸总量与鲜味值、单宁含量与涩味回味值、总酸含量与酸味值、固酸比与甜味值均呈正相关性。低浓度氯吡脲使用对草莓的甜味、酸味等滋味和风味组成具有正面影响,而无论氯吡脲浓度使用高低对咸味和鲜味等滋味和风味组成均有负面影响。     

Taste interaction of ethyl alcohol with sweet, salty, sour and bitter compounds

The influence of ethyl alcohol in concentrations ranging from 4 to 24%, on the perceived taste intensities of sucrose, citric acid, quinine, and sodium chloride was determined by 24 subjects. A paired comparison method was used in which subjects selected the sample with the greater taste intensity (sweetness, sourness, bitterness or saltiness) as well as rating the intensity on a 13-point scale. The alcohol generally enhanced the sweetness of sucrose, with results varying slightly according to the subjects' task. The sourness of citric acid, and the saltiness of sodium chloride at all but the lowest concentration, were depressed by increasing additions of alcohol. Alcohol significantly enhanced the bitterness of quinine at all four concentrations. Although these results disagree with previously reported electrophysiological measurements on alcohol-quinine mixtures, they were internally consistent, and meaningful in terms of alcoholic beverage consumption behaviour.     

Red Wine and Model Wine Astringency as Affected by Malic and Lactic Acid

Red wines and model solutions containing grape seed phenols were assessed for perceived astringency, bitterness and sourness by a panel of trained assessors using time-intensity (T–I) methodology. The effect of lactic and malic acid on perception of these attributes was evaluated at two pH values, by adding different amounts of acids. Maximum intensity (I_max) and total duration (T_tot) of astringency increased with decreasing pH in model solutions and red wine, but no differences were found between malic and lactic acid on perception of astringency. The pH and the acid type did not affect any of the bitterness T-I parameters. However, sourness showed an increase in 1_max and T_tot with decreasing pH.     

Sensory quality and compositional characteristics of blackcurrant juices produced by different processes

Effects of enzymatic and non-enzymatic juice pressing on key orosensory and chemical quality factors of blackcurrant juices were studied in laboratory scale using berries of five different cultivars (Mortti, Mikael, Marski, Ola and Breed15). Enzymatic processing increased the juice yield by 10–22% and the content of various phenolic compounds in juice by 4–10-fold as compared to the non-enzymatic process. Higher intensity of the mouth-drying astringency of the enzyme-aided juice was the most significant orosensory difference between the processes. Juices of different blackcurrant cultivars varied in sweetness, sourness and bitterness. The most intensive sensory attributes of the juices were sourness and puckering astringency regardless of processing method. They correlated positively with each other and were contributed by acid content and pH. In enzyme-aided juices, the contents of flavonol glycosides and hydroxycinnamic acids were associated with mouth-drying astringency, and sugar/acid ratio correlated with sweetness. These correlations were less clear in non-enzyme juices possibly due to lower content of phenolic compounds and the high content of pectin.     

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.     

不同抑制剂对苦瓜粉味觉的修饰效果

以苦瓜粉浸泡液为对象,分别添加乳酸锌、新甲基橙皮苷二氢查尔酮、γ-氨基丁酸、酪朊酸钠、全脂乳粉、阿魏酸、聚葡萄糖、三氯蔗糖、新地奥明、单磷酸腺苷,采用感官评定结合标签量值评估（general labeled magnitude scale,gLMS）法评价不同抑制剂对苦瓜粉浸泡液苦味、后苦味、甜味、后甜味、涩味以及特征风味的影响;通过模糊评判筛选抑制效果最佳的3?种抑制剂进行正交试验,评价复合抑制剂对苦瓜粉浸泡液苦味及后苦味的影响。结果表明,10?种抑制剂对苦瓜粉浸泡液的苦味、后苦味、涩味均有显著抑制作用。其中新甲基橙皮苷二氢查尔酮对苦味、后苦味抑制作用最强;乳酸锌对后苦味、γ-氨基丁酸对苦味也有较好的抑制作用;酪朊酸钠对涩味的抑制作用最为明显;三氯蔗糖、聚葡萄糖、酪朊酸钠、全脂乳粉会增加整个体系的甜味及后甜味。以乳酸锌、新甲基橙皮苷二氢查耳酮、γ-氨基丁酸3?种抑制剂进行正交试验,结果表明1?g苦瓜粉添加0.60?mg新甲基橙皮苷二氢查耳酮、3.98?mg?γ-氨基丁酸、4.46?mg乳酸锌时,苦瓜粉浸泡液苦味和后苦味可以从明显降低到基本察觉不到,且苦瓜特征风味保留较好,无其他异味存在。     

YEAST STRAIN AND THE FORMATION OF FLAVOUR COMPONENTS IN CIDER

Two apple juices were fermented at 8°C and 18°C using thirteen strains of Saccharomyces uvarum. Glucose, fructose, malic, lactic, isobutanol, 2–3 butanediol, isoamyl alcohol, ethyl acetate and titratable acidity were determined in the two resulting experimental ciders. This data was correlated by means of multiple regression equations derived from earlier work with the following organoleptic characteristics: sweetness, sourness, fruity, scented, sharp and irritating flavours and a “global hedonic score” for overall acceptability. A significant effect of yeast strain could be detected on all component concentrations except ethanol, ethyl acetate, amyl alcohols and titratable acidity. The amounts of malic acid and titratable acidity found in cider depends mainly on the source of the juice. The anticipated effect of the source of the juice on sourness and on sharpness and fruity flavours is therefore significant. Yeast strain is also expected to have a significant effect on fruity and sharp flavours as well as on overall acceptability.     

Effects of viscosity on the bitterness and astringency of grape seed tannin

To examine the separate effects of viscosity and sweetness on astringency, aqueous solutions of grape seed tannin (GST) were thickened with carboxymethyl cellulose (CMC) from 2 to 45 cP (experiment 1) or sweetened with 0 to 1.8 g/L aspartame (experiment 2). Trained subjects continuously rated astringency and bitterness in duplicate. Subjects were categorized by the salivary flow induced by citric acid and ability to taste n-propyl thiouracil (PROP). In experiment 1, maximum intensity and total duration of astringency were significantly decreased as viscosity rose, although time to maximum intensity of astringency was not affected. Maximum intensity and total duration of bitterness were not significantly affected by increasing viscosity; however, the onset of bitterness was significantly delayed. In experiment 2, increasing sweetness had no affect on any astringency parameter, although maximum intensity of bitterness was significantly decreased. Neither PROP nor salivary flow-status had any effect on perception of bitterness or astringency in either experiment.     

Sensory characteristics and relative sweetness of tagatose and other sweeteners

The present study investigated the sensory characteristics and relative sweetness of tagatose, an emerging natural low-calorie sweetener with various functional properties, compared to other sweeteners (sucrose, sucralose, erythritol, rebaudioside A), over a wide range of sweetness commonly found in foods and beverages (3% to 20% sucrose [w/v]). A total of 34 subjects evaluated aqueous solutions of the 5 sweeteners for the perceived intensities of sweetness, bitterness, astringency, chemical-like sensations, and sweet aftertaste, using the general version of the Labeled Magnitude Scale. The relationship between the physical concentrations of the sweeteners and their perceived sweetness (that is, psychophysical functions) was derived to quantify the relative sweetness and potency of the sweeteners. The results suggest that tagatose elicits a sweet taste without undesirable qualities (bitterness, astringency, chemical-like sensations). Out of the 5 sweeteners tested, rebaudioside A was the only sweetener with notable bitterness and chemical-like sensations, which became progressively intense with increasing concentration (P < 0.001). In terms of perceived sweetness intensity, the bulk sweeteners (tagatose, erythritol, sucrose) had similar sweetness growth rates (slopes > 1), whereas the high-potency sweeteners (sucralose, rebaudioside A) yielded much flatter sweetness functions (slopes < 1). Because the sweetness of tagatose and sucrose grew at near-identical rates (slope = 1.41 and 1.40, respectively), tagatose produced about the same relative sweetness to sucrose across the concentrations tested. However, the relative sweetness of other sweeteners to sucrose was highly concentration dependent. Consequently, sweetness potencies of other sweeteners varied across the concentrations tested, ranging from 0.50 to 0.78 for erythritol, 220 to 1900 for sucralose, and 300 to 440 for rebaudioside A, while tagatose was estimated to be approximately 0.90 times as potent as sucrose irrespective of concentration. Practical Application: The present study investigated the sensory characteristics and relative sweetness of tagatose, an emerging natural low-calorie sweetener, compared to other sweeteners. Study results suggest that tagatose elicits a sweet taste without undesirable qualities over a wide range of concentrations. Tagatose produced about the same relative sweetness to sucrose across the concentrations tested, while the relative sweetness of other sweeteners was highly concentration dependent. The present data provide a general guideline when considering the use of tagatose and other sweeteners in foods and beverages.     

The phenolics of ciders: Bitterness and astringency

The bitterness and astringency of defined procyanidin fractions from bittersweet English ciders were assessed using a paired-comparison tasting technique. The results demonstrate that, while no one procyanidin can be uniquely identified with bitterness or astringency, bitterness is associated with oligomeric procyanidins reaching a maximum with the epicatechin tetramer whereas astringency is characteristic of higher-molecular-weight procyanidins. The effect of presentation media on taste response was also studied. High sugar and buffer strength suppressed the perceived bitterness, whereas ethanol increased bitterness but simultaneously decreased astringency. It is shown that the observed taste differences between two bittersweet ciders and the taste-modifying effect of ethanol can be explained satisfactorily by current theories of taste.     

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.     

Flavan-3-ols: nature, occurrence and biological activity

Representing the most common flavonoid consumed in the American diet, the flavan-3-ols and their polymeric condensation products, the proanthocyanidins, are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies and supplements. Their presence in food affects food quality parameters such as astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation. The ability of flavan-3-ols to aid food functionality has also been established in terms of microbial stability, foamability, oxidative stability, and heat stability. While some foods only contain monomeric flavan-3-ols [(-)-epicatechin predominates] and dimeric proanthocyanidins, most foods contain oligomers of degree of polymerization values ranging from 1-10 or greater than 10. Flavan-3-ols have been reported to exhibit several health beneficial effects by acting as antioxidant, anticarcinogen, cardiopreventive, antimicrobial, anti-viral, and neuro-protective agents. This review summarizes the distribution and health effects of these compounds.     

EFFECT OF HYDROCOLLOIDS ON ORAL VISCOSITY AND BASIC TASTE INTENSITIES *

Abstract. This study determined the effects of low concentrations of five food hydrocolloids on the taste intensities of aqueous solutions of sucrose, citric acid, sodium chloride, saccharin, and caffeine. The effects of the taste compounds on both oral and Brookfield viscosities were also measured. In general, sourness of citric acid and bitterness of caffeine were suppressed, while sweetness of saccharin was enhanced. Among the basic tastes, sourness was affected the most and saltiness the least. Except for sucrose, modification of taste intensity was independent of viscosity, and appeared to be related to the physicochemical properties of the hydrocolloid and the taste compound. About 16 cps were needed to reduce significantly the sweetness of sucrose. The taste compounds altered oral and physical viscosities differentially depending on the specific gum/taste combination. Generally, viscosity was reduced by the addition of all taste compounds except sucrose which increased the physical viscosity.     

Sensory, chemical and gas chromatographic evaluation of five raspberry cultivars

Five raspberry cultivars, ‘Chilcotin’, ‘Chilliwack’, ‘Meeker’, ‘Skeena’ and ‘Tulameen’, were evaluated for sensory attributes, and chemical and flavor volatile compounds. ‘Chilliwack’ and ‘Tulameen’ received high ratings in sweetness and overall impression with high soluble solids, total sugars and sugar:acid ratio. ‘Chilcotin’ rated low in overall impression and sweetness, and high in sourness and astringency, with low soluble solids, sugar:acid ratio and total sugars, and high titratable acidity. Principal factor analysis (PFA) of the sensory results separated the cultivars based on desirable (appearance, color, texture, aroma and sweetness) and less desirable (sourness, bitterness, astringency and off-flavor) attributes. Twenty-eight volatile compounds were analyzed by dynamic headspace and 18 identified by gas chromatography-mass spectrometry (GC-MS), most of which were terpenes which included -pinene, sabinene, γ-terpinene, - and β-ionone and caryophyllene. Volatile compounds varied among cultivars, with benzaldehyde (11·1–31·8%), -pinene (4·0–11·5%), ethyl heptanoate (6·9–15·2%), β-myrcene (13·2–19·6%) and γ-terpinene (12·2–20·0%) as the predominant volatiles. Correlation analysis established no relationships between sensory and chemical data with volatile compounds.     

YEAST STRAIN AND KINETIC ASPECTS OF THE FORMATION OF FLAVOUR COMPONENTS IN CIDER

An apple juice was fermented at 8°C using twelve strains of Saccharomyces uvarum. Glucose, fructose, malic and L-lactic acids, isobutanol, 2,3 butanediol, isoamyl alcohol, ethyl acetate and titratable acidity were determined and monitored in the course of fermentation. It was observed that yeast strains differed from one another mainly in fermentation rates. When components were determined in ciders of the same remaining fructose concentration, rather than after the same fermentation time, the only significant effect of the yeast strain was on the amounts of glucose and ethanol in sweeter cider (fructose 34 g/litre), or on the amounts of glucose, acetic acid, isobutanol and amyl alcohols in dryer ciders (fructose 17 g/litre). A sensory analysis showed that standard deviations of concentrations of remaining or formed components in ciders fermented by different yeast strains, was sufficient to be detected by the taste panel. Added glucose in this range of concentration (1.5 g/litre) in cider reduced the perception of sourness while the addition of acetic acid (0.3 g/litre) reduced the perception of the scented flavour. Added Isobutnol (6 mg/litre) reduced the perception of sweetness. No significant effect of added isoamyl alcohol (30 mg/litre) could be detected. Chemical determinations were correlated by means of regression equations derived from earlier work with some organoleptic characteristics. No anticipated effect of the yeast strain could be detected on any studied flavour characteristic. It is concluded that in ciders of the same attenuation, the effect if it does exist, of the S.uvarum strain isolated from ciders, must be low.     

Sensory Characteristics of Cottage Cheese Whey and Grapefruit Juice Blends and Changes During Processing

Studies were conducted to determine the sensory characteristics of pasteurized blends of cottage cheese whey and grapefruit juice (0%, 25%, 50%, 75% and 100% whey), and the effects of processing alternatives and storage at 3°C. A trained sensory panel rated six attributes (grapefruit, sweetness, sourness, astringency, cheesiness, saltiness). Cheesiness and saltiness increased, while sourness, astringency, sweetness, and grapefruit flavor decreased as the percentage of whey increased. Protein removal did not affect the sensory characteristics, but vacuum stripping reduced cheesiness and increased grapefruit flavor and sweetness. Lactose hydrolysis increased sweetness and decreased cheesiness in blends with more than 50% whey. The flavor of most blends was stable for 14 wk at 3°C.     

Perception of taste intensity in solutions of random-coil polysaccharides above and below c

Sensory paired comparison tests were used to study differences in taste intensity in solutions of hydroxypropylmethyl cellulose (HPMC) at concentrations above (1.0% w/w) and below (0.2% w/w) c^*, the coil-overlap concentration (the point at which viscosity changes abruptly with increasing thickener). The sweetness intensities of aspartame (250 ppm), sucrose (5% w/w), fructose (4.5% w/w) and neohesperidin dihydrochalcone (39 ppm) and the saltiness of sodium chloride (0.35%) were all found to be significantly reduced in the more viscous HPMC solution. There was no significant effect of HPMC concentration on the acidity of citric acid (600 ppm) or the bitterness of quinine hydrochloride (26 ppm). The sweetness intensities of sucrose and aspartame were likewise investigated in two further hydrocolloid solutions, guar gum and λ-carrageenan. Experiments were designed so that the ratios of the thickener concentrations (above and below c^*) to their measured c^* values remained constant. The sweetness of sucrose was found to be significantly reduced in the more viscous guar gum solution (P<0.05) and that of aspartame was reduced in the λ-carrageenan above c^* (P<0.001). A multiple paired comparison design was used to show that the perceived sweetness of 6.5% sucrose in 1.0% HPMC did not differ significantly from that of 5% sucrose in 0.2% HPMC. The magnitude of effect with aspartame was broadly analogous.