STEVIOSIDE AS A REPLACEMENT OF SUCROSE IN PEACH JUICE: SENSORY EVALUATION

The suitability of stevioside as a sweetener in peach juice was investigated. Comparison between stevioside and sucrose in terms of sweetness, sweet and bitter aftertastes were determined both in water and peach juice. The results demonstrated that 160 mg/L of stevioside may replace 34 g/L of sucrose in juice, with a 25% decrease in calories, without affecting the sensory characteristics of the product. Synergistic and inhibitory effects between sucrose and stevioside were also monitored at different stevioside concentration. A new juice formulation sweetened with a binary mixture of stevioside (160 mg/L) and sucrose (56 g/L) was not significantly different in terms of desirability from a reference product sweetened with 9% sucrose.     

Sensory studies with sucrose-maltol mixtures

Panellists tasted sucrose solutions mixed with the enhancermaltol at concentrations of 50, 100 and 200 p.p.m. Nose-clipswere worn to prevent the identification of the maltol by itssmell. At these levels maltol is reported to enhance sweetness.In the present study these concentractions of maltol did notsignificantly enhance the intensity or persistence of the sweetnessof sucrose. In another experiment, panellists tasted solutionsof 5% sucrose mixed with 312 p.p.m. maltol. Tastings were performedwith and without the panellists wearing nose-clips. The smellof the maltol did not confuse trained panellists into believingthat the mixture of sucrose and maltol tasted sweeter than sucrosealone. However, in another experiment when both smell and tastewere assessed, untrained panellists found that a sucrose-maltolsolution possessed an overall greater sweetness than an equivalentconcentration of sucrose. That is, if panellists concentrateonly on taste then maltol does not appear to enhance sweetnesswhereas if od our and smell are assessed then maltol was foundto elevate total sweetness intensity. Triangle tests were performed to determine whether lemonadedrinks containing 15 p.p.m. maltol were perceptually differentfrom the original lemonade drink containing no maltol. No significantdifference was found between the two lemonades and it was concludedthat the addition of a sub-threshold concentration of maltoldid not significantly affect the taste of lemonade drinks.     

A REAPPRAISAL OF THE USE OF MULTIDIMENSIONAL SCALING TO INVESTIGATE THE SENSORY CHARACTERISTICS OF SWEETENERS

Previous investigations of the sensory characteristics of sweeteners using a multidimensional scaling (MDS) approach, have involved sweeteners which were not matched for sweetness. Under such circumstances, part of the estimated distance between sweeteners is attributable to sweetness differences. This detracts from the value of the consequent MDS space, when the main objective is usually to investigate sensory characteristics other than sweetness. In this study, the MDS approach was applied to sweetener solutions which were matched for sweetness with 5% sucrose. The direction of any residual sweetness differences was identified by including 1,3,5 and 7% sucrose solutions, all matched to equal viscosity, in the study. From the resulting three dimensional MDS sweetener space, it was evident that Dimension 1 was almost exclusively due to sweetness differences whereas Dimensions 2 and 3 were devoid of influence from sweetness and hence represent the sweeteners with respect to their other sensory characteristics.     

POTENCY OF SWEETNESS OF ASPARTAME, D-TRYPTOPHAN AND THAUMATIN EVALUATED BY SINGLE VALUE AND TIME-INTENSITY MEASUREMENTS

Perceived sweetness of sucrose, aspartame, D-tryptophan and thaumatin in a sour, citric acid background was analyzed in terms of the potency of these compounds relative to sucrose-water combinations. Potencies of the sweeteners were determined from (1) maximum intensity using single value and time-intensity (T-I) measurements and (2) average intensity calculated as the ratio of area under the T-I curve and total perceived time. Stevens' law was applied to sweet responses, either in static or dynamic conditions. It was found that the exponent of the concentration-response function reflected the relative capacity of a compound to sweeten a given food and stressed differences of potency among sweeteners. Aspartame, D-tryptophan and thaumatin exhibited a decrease in sweetness potency relative to sucrose as sweetness increased from 10 to 100% of the full scale of response. Across the entire sweetness range, thaumatin showed the greatest potency but its long persistence time led to differentiate this intense sweetener from the other sweeteners evaluated.     

FOCUSED DIFFERENCE TESTING FOR THE ASSESSMENT OF DIFFERENCES BETWEEN ORANGE JUICES MADE FROM ORANGE CONCENTRATE

Focused difference testing was applied to two orange juices prepared from frozen concentrate. Differences were noted between the juices for darkness of color, visual appearance of pulpiness, resistance to tongue movement, flavor by mouth, odor, overall taste and taste other than sweetness. The logic and approach of focused difference testing is discussed and contrasted with other sensory analytical techniques.     

HEDONIC SCALES ARE A BETTER PREDICTOR THAN JUST-ABOUT-RIGHT SCALES OF OPTIMAL SWEETNESS IN LEMONADE1

A comparison of hedonic scales and just-about-right (JAR) scales is needed because data in previous studies using JAR scales suggest that predicted optimum levels of ingredients often are not the same as the levels in products that currently are sold successfully. Thus, in this research, consumers tested lemonade varying in sugar concentration from 6% to 14%, using (1) a JAR scale formed by boxes or a line and (2) a hedonic box-type scale. Predicted “optimum” levels of sweetness for the lemonade and differences in liking for the formulations were determined. The JAR line and box scales gave similar predicted optimal results (9.2% and 9.4% sucrose, respectively), which were significantly lower than the hedonic scale results (10.3% sucrose). In a preference test, consumers significantly preferred the 10.3% sugar lemonade over the 9.3% concentration, indicating that, based on paired preference testing, the hedonic scale resulted in better prediction of optimal sweetness than the JAR scale.     

GUSTATORY REACTION TIME AND TIME INTENSITY MEASUREMENTS OF TREHALOSE AND SUCROSE SOLUTIONS AND THEIR MIXTURES

Dynamic sweetness perception of commercial food grade trehalose, sucrose solutions and their mixtures were studied for a wide range of concentrations. For gustatory reaction time (GRT), concentrations ranged from 2.3 to 13.8% for sucrose and up to 23.0% for trehalose. For time intensity (T-I) sucrose or trehalose solutions (concentration range 2.3–36.8%) and their combinations (23.0 and 36.8% total solids) were analyzed. Trehalose had bigger GRT along the studied range. Both sugars presented similar values for persistence and times of plateau and to maximum intensity, while a significant difference was observed in intensity and GRT at equal concentrations. Trehalose had longer persistence than sucrose in equi -sweet solutions. Overall sweetness profile of some sucrose solutions (i.e., 29.9% sucrose solution and 0.6 sucrose/trehalose ratio mixture at 36.8% total solids) were perceived as similar to mixtures of sucrose/trehalose or single trehalose solutions, which suggests the possibility of sugar replacement without completely modifying sweetness perception.

PRACTICAL APPLICATIONS

It has been suggested that trehalose may be a potential substitute for sucrose and other sugars used in food formulation because, although its chemical structure is very similar to that of sucrose, it is more stable at low pH and high temperatures. It is not involved in caramelization and does not participate in Maillard reaction with amino acids/proteins. In order to fully establish the potential of trehalose as a functional replacement of sucrose we have determined the sweetness dynamic profile (gustatory reaction time and time-intensity curves) of trehalose solutions and sucrose/trehalose solutions; this aspect is needed for adequately replacing (partially or totally) sucrose in food systems.     

Strawberry odor, but not red color, enhances the sweetness of sucrose solutions

Several investigators have recently reported that odor and colorcan influence the sweetness of stimuli containing sucrose. Theseeffects were examined further by assessing the effect of redcoloring and strawberry odorant on the sweetness ratings ofaqueous solutions of sucrose. Two methods of olfactory stimulationwere used: (i) sip and spit, and (ii) swallowing the solutions.It was anticipated that swallowing the solutions would enhancethe olfactory effects by augmenting retronasal olfactory stimulation.The strawberry odor induced a small, but significant increasein sweetness for both the sip and spit and swallowing condition.There was a tendency for this effect to be more consistent andstable in the swallowing condition. Red coloring had no effecton sweetness.     

TEMPORAL STUDY OF SUCROSE AND FRUCTOSE RELATIVE SWEETNESS

Time-Intensity (T-I) and Gustatory Reaction Time (GRT) methodologies were used to study the relative sweetness of sucrose and fructose at 25C. Eleven panelists evaluated nine concentrations (5 to 45%, w/v) of sucrose and fructose by T-I and seven parameters were determined. Higher values were obtained for fructose at 25, 30 and 35% for Maximum Intensity; at 35, 40 and 45% for the Area Under the Curve; at 40 and 45% for Time to decline the Intensity to half of its maximum value and at 45% for Rate of Increase. Ten subjects evaluated seven concentrations (3 to 15%, w/v) of sucrose and fructose by the GRT procedure. Fructose had shorter GRT than sucrose at 3 and 4.5%. Thus, fructose at 25, 30 and 35%, has a more intense and at 40% more persistent sweetness than sucrose and is detected earlier than sucrose at concentrations near gustatory threshold.     

NUTRITIONAL, PHYSICAL AND SENSORY CHARACTERISTICS OF VARIOUS CHOCOLATE-FLAVORED PEANUT–SOY BEVERAGE FORMULATIONS

Mixture design and pilot‐plant scale processing protocol were developed to obtain the best chocolate‐flavored peanut–soy beverage formulation. Twenty‐eight formulations were evaluated for nutritional (lysine content), physical (viscosity [η], visual stability index [VSI]) and nine sensory (consumer liking) attributes. Lysine contents (mg/g protein) (44.1–57.1) were close to the reference (51.0) and in the desirable range observed for other peanut‐based beverages. Higher viscosity indicated lower consumer liking, but lower viscosity resulted in lower VSI. Formulation ?8 having 43.9% peanut, 36.3% soy protein isolate (SPI) and 19.8% chocolate syrup had the highest consumer liking and the best balance of physical properties (η = 41.5 mPa·s; VSI = 0.99). As compared to commercial chocolate milk (6 = slightly like to 7 = moderately like), it was rated higher for appearance (7.0), color (6.8) and sweetness (6.4). Two SPI formulations (?6 and ?7) and a soy flour formulation (?14) were rated highest for aroma (6.2), color (7.0) and flavor (6.0), respectively.     

Reducing red color intensity of seafood wastewater in facultative pond

Studies were carried out on the growth of Chromatium sp. on seafood wastewater (SFWW), which under facultative conditions and light exposure produced red pigment. The strain grew and utilized organic matter in both dark and light exposure conditions, but it produced red pigment when exposed to light. The growth was repressed by aerobic condition. The red color intensity was reduced by about 32.5+/-1.5 and 70.8+/-2.8% when kept under dark and static conditions, or aerobic and light exposure conditions, respectively. The COD of SFWW and the number of cells of Chromatium sp. were also rapidly reduced by about 78.6+/-2.7 and 92.0+/-1.0%, respectively, under aerobic and light exposure condition. KNO3 and FeCl3 also reduced red color intensity and maximum removal of organic matter and red color were 30 and 4 mg/l, respectively. Aerobic conditions increased the color removal efficiency with 30 mg/l KNO3 and 4 mg/l FeCl3 treatments up to 96.5+/-1 and 98.9+/-1%, respectively.     

EFFECTS OF A SLIGHT COLOR VARIATION ON CONSUMER ACCEPTANCE OF ORANGE JUICE

Three hundred and forty-two consumers participated in a study examining slight color variation in orange juice. Panelists evaluated two orange juice samples; unadulterd juice and the same juice with a slight green off-color. The color manipulation reduced consumer acceptance of the color of the adulterated sample but had little influence on ratings of flavor, sweetness or overall liking. Older panelists were more strongly influenced by the color manipulation and showed a clear preference for the flavor of the control sample as compared to the adulterated sample. These data suggest that color was important for the visual appeal of orange juice, but the color change alone was not sufficient to alter consumer acceptance of this product.     

烟管孔菌G14产锰过氧化物酶条件优化及其对染料的脱色

利用组织分离从未成熟有机蓝莓的表皮中分离出菌株G14,根据其菌落形态、ITS序列对比及系统发育树的分析,鉴定菌株G14为一株烟管孔菌Bjerkandera adusta.菌株G14可以分泌漆酶(laccase,Lac)、木质素过氧化物酶(lignin peroxidase,LiP)和锰过氧化物酶(manganese p...     

SENSORY EVALUATION OF VANILLA-DAIRY DESSERTS BY REPERTORY GRID METHOD AND FREE CHOICE PROFILE

“Natillas” are semisolid dairy desserts widely consumed in Spain, with notable differences existing between commercial brands in their composition and sensory and physical properties. The repertory grid method, in conjunction with the free choice profile (FCP), was used to provide data on how consumers perceived eight commercial “natillas” samples. The most frequent terms used were: vanilla flavor, sweetness, consistency and liquid texture as described by 77, 67, 57 and 53% of the consumers, respectively. A three‐dimensional solution was chosen. Dimension 1 accounted for 27.23% of variance and separated the samples largely by yellow‐color intensity and consistency. Dimension 2 (15.88%) was mainly related to the visual attributes of texture, creaminess and different notes of flavor. The third dimension (11.34%) was related to structural‐texture attributes, orange‐yellow color and acid and artificial flavors. The assessors plot showed two clusters. Analysis of each group data revealed differences in their perception of sample variation, mainly regarding texture and color.     

Effect of repeated presentation on sweetness intensity of binary and ternary mixtures of sweeteners

The purpose of the present study was to determine the effect of repeated presentation of the same sweet stimulus on sweetness intensity ratings. The sweet stimuli tested in this study were binary and ternary blends of 14 sweeteners that varied widely in chemical structure. A trained panel evaluated the sweetness intensity over four sips of a given mixture presented at 30 s intervals. The individual components in the binary sweetener combinations were intensity-anchored with 5% sucrose, while the individual sweeteners in the ternary mixtures were intensity-anchored with 3% sucrose (according to formulae developed previously). Each self-mixture was also evaluated (e.g. acesulfame-K-acesulfame-K). The main finding of this study was that mixtures consisting of two or three different sweeteners exhibited less reduction in sweetness intensity over four repeated sips than a single sweetener at an equivalent sweetness level. Furthermore, ternary combinations tended to be slightly more effective than binary combinations at lessening the effect of repeated exposure to a given sweet stimulus. These findings suggest that the decline in sweetness intensity experienced over repeated exposure to a sweet stimulus could be reduced by the blending of sweeteners.     

产紫青霉突变菌株Li-3-9的发酵条件优化及红色素安全性评价

本实验对前期研究得到的具有高产红色素能力的产紫青霉突变菌株Penicillium purpurogenum Li-3-9的发酵条件进行优化的同时作出了对红色素的安全性评价。在单因素试验的基础上,采用Box-Behnken试验设计优化了蔗糖浓度、酵母膏浓度和装液量对红色素色价的影响;并且研究了P. purpurogenum Li-3-9产生的红色素对斑马鱼胚胎的毒性效应。结果表明,最佳发酵条件为：蔗糖40g/L、酵母膏4g/L、装液量为45mL、接种量4%、培养温度32℃、初始pH值6.9、培养时间168h、摇床转速150r/min,红色素色价最高达到了11.4U/mL。通过计算斑马鱼胚胎致死率、心率、畸形率及孵化率可知,该色素无致死毒性,并且对斑马鱼胚胎发育具有一定的促进作用。     

Light-susceptibility of camptothecin production from<Emphasis Type="Italic">in vitro</Emphasis> cultures of<Emphasis Type="Italic">Camptotheca acuminata</Emphasis> Decne

Production of camptothecin (CPT) from callus cultures ofCamptotheca acuminata Decne was affected by light and culture conditions. Among the culture media tested, modified B5 medium containing 3% (w/v) sucrose, 2 mg/L 2,4-D, 2 times of MS medium vitamins, 500 mg/L casein hydrolysate, 250 mg/L myo-inositol, 0.05% (w/v) activated charcoal, and 0.15% (w/v) gelite was used for callus induction. The highest cell growth and CPT production were obtained in dark and green light condition, respectively. Photoperiod has no effect on cell growth and CPT production. Both cell growth and CPT production were also influenced by combination ratio of red and blue light. Cell growth and CPT production were the highest in the ratio of red and blue light 90∶10.     

Revisiting sugar-fat mixtures: sweetness and creaminess vary with phenotypic markers of oral sensation

Genetic variation in oral sensation presumably influences ingestive behaviors through sensations arising from foods and beverages. Here, we investigated the influence of taste phenotype [6-n-propylthiouracil (PROP) bitterness, fungiform papillae (FP) density] on sweet and creamy sensations from sugar/fat mixtures. Seventy-nine subjects (43 males) reported the sweetness and creaminess of water or milk (skim, whole, heavy cream) varying in sucrose (0-20% w/v) on the general Labeled Magnitude Scale. Sweetness grew with sucrose concentration and when shifting from water to milk mixtures--the growth was greatest for those tasting PROP as most bitter. At higher sucrose levels, increasing fat blunted the PROP-sweet relationship, whereas at lower levels, the relationship was effectively eliminated. Perceived sweetness of the mixture exceeded that predicted from the sum of components at low sucrose concentrations (especially for those tasting PROP most bitter) but fell below predicted at high concentrations, irrespective of fat level. Creaminess increased greatly with fat level and somewhat with sucrose. Those tasting PROP most bitter perceived greater creaminess in the heavy cream across all sucrose levels. Perceived creaminess was somewhat lower than predicted, irrespective of PROP bitterness. The FP density generally showed similar effects as PROP on sweetness and creaminess, (but to a lesser degree) and revealed potential taste-somatosensory interactions in weakly sweet stimuli. These data support that taste phenotype affects the nature of enhancement or suppression of sweetness and creaminess in liquid fat/sugar mixtures. Taste phenotype effects on sweetness and creaminess likely involve differential taste, retronasal olfactory, and somatosensory contributions to these perceptual experiences.