Strawberry Yogurt Research Articles

Formulations and Processing of Yogurt Affect the Microbial Quality of Carbonated Yogurt

Carbonation, flavor, culture type, pH, and storage time were varied to investigate the effects of these variables and their interactions on the growth of both typical and nontypical yogurt cultures and some contaminating bacteria. Two types of yogurt cultures (YC-470 and YC-180) were used as the source of typical yogurt bacteria, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. In addition, Lactobacillus acidophilus (LA-K) and Bifidobacterium longum ATCC 15707 were added as nontypical yogurt cultures to make sweetened low fat (1%) Swiss-style plain, strawberry, and lemon yogurts. Samples were incubated at 43°C until pH values of 5.0 or 4.2 were reached. Strawberry yogurts at low (4.2) and high (5.0) pHs were divided into three portions, which were separately inoculated with contaminating bacteria, Bacillus licheniformis ATCC 14580, Escherichia coli ATCC 11775, and Listeria monocytogenes Scott A. After incorporation of carbon dioxide (1.10 to 1.27vol.me of CO2 gas dissolved in water), the yogurt was stored at 4°C for a 90-d period. Carbon dioxide did not affect the growth of typical or nontypical yogurt bacteria. Also, CO2 did not inhibit the growth of undesirable microorganisms. In general, low levels of CO2 did not affect the bacterial population in yogurt. The microflora of yogurt were influenced by culture type, pH, flavor type, and storage time or their interactions.

IDENTIFICATION OF SENSORY COLOR OPTIMA OF STRAWBERRY YOGURT

ABSTRACTCommercially available strawberry yogurts were subjected to preference ranking done by an untrained panel and to instrumental color analysis. Spectral reflectance data and color values expressed in the CIELAB system revealed different color properties of the yogurts, mainly with respect to the hue angle determining whether a product is, e.g., dominantly red or dominantly orange. Sensory evaluations resulted in three groups of products being significantly different from each other with respect to their preference patterns. The tomato color index originally proposed for measuring the ripening index of tomatoes appeared to be useful to reduce 3‐dimensional yogurt color values to one dimension and to construct a function of preference ranks versus instrumentally measured data.

SENSORY AND INSTRUMENTAL EVALUATION OF STRAWBERRY YOGURT COLOR

ABSTRACTEleven samples of strawberry yogurt prepared with different red color concentrations using Ponceau 4R (E‐124) were evaluated by instrumental and sensory methods. Color intensity evaluation was carried out by a panel of eight assessors specifically trained to measure strawberry color in yogurt. Color acceptability was measured with 120 regular and frequent consumers of yogurt. Color was measured with a Minolta Chroma Meter CR‐200b, obtaining parameters L*, a* and b*. Principal component analysis was performed on the instrumental variables. Regression models between the instrumental first principal component, red color concentration, sensory intensity, and acceptability allowed determining quality control limits for red color attribute. These limits may be controlled by selecting either instrumental or sensory methods, being the latter easy to implement and providing dependable results.

Effects of dietary fat, nutrition labels, and repeated consumption on sensory-specific satiety

This study investigated whether energy from fat, nutrition information, and/or repeated consumption of a palatable snack food affects the development of sensory-specific satiety (SSS). Participants (51 males and 44 females) ate an afternoon snack of potato chips in a laboratory for two 10-day (Monday–Friday) sessions in a repeated measures, cross-over design. In one 10-day session, participants were given regular, full-fat potato chips (22.2 kJ/g; 150 kcal/oz) and, in the other, they were given potato chips made with olestra (11.8 kJ/g; 80 kcal/oz), a non-absorbable fat replacer. Information about the fat and energy content of the chips was provided to half the participants, while the other half was not informed. In both sessions, participants were instructed to consume the potato chips ad libitum. Initial ratings of sensory properties of the two types of chips did not differ significantly. In SSS tests, participants rated sensory properties of the chips and four test foods (turkey, strawberry yogurt, cookie, and carrot) on days 1, 5, and 10 of the 10-day sessions. Following consumption, ratings of pleasantness of taste and texture and prospective consumption of both types of chips declined compared to the test foods. Further analyses showed that the development of SSS was not affected by the fat and energy content of the chips, the provision of nutrition information, or repeated consumption.

Social and physiological factors affecting food intake in elderly subjects: an experimental comparative study

The decline in average food intake in elderly people is attributed to both physiological and social factors. These factors are usually studied in isolation. The present study concerns an experiment in which the effect of social setting on food intake is compared with the effect of physiological challenges on food intake in 24 elderly subjects (6 men and 18 women, age: 75± 4.9 years, BMI=26.6±3.5 kg/m 2). Physiological effects were assessed using a preload-test-meal design with a no load, 0 kJ; and 4 preload conditions: low carbohydrate/low fat, low energy, 0.4 MJ; high fat, low carbohydrate, medium energy, 1.1 MJ; high carbohydrate, low fat, medium energy 1.1 MJ; high fat, high carbohydrate, high energy, 1.8 MJ. The preloads consisted of 300 g of strawberry yogurt drink, and were served at 10:00 a.m. The test-meal, served 90 min after the preload consumption, was a lunch of which subjects could eat ad libitum. Social effects on food intake were assessed by using two social settings at lunchtime: cozy and non-cozy. Dependent variables were food intake at lunch and ratings of appetite assessed before the preload, and between preload and test-meal. Results showed that energy intake at lunch was significantly decreased after the high carbohydrate preload and the high fat–high carbohydrate preload (intake compensation of 23 and 15%, respectively), compared to the no preload condition. The other preloads did not have a significant effect on food intake. Energy intake was of 2.5±0.5 MJ in the cozy social setting and of 2.5±0.6 MJ in the non-cozy one. Appetite feelings were generally lower after the preload conditions compared to the no load condition ( P<0.05), but there were no significant effects of the macronutrient or energy content of the preloads on appetite feelings. It is concluded within the context of this study in healthy elderly subjects that food intake responds more to physiological challenges than to short-term changes in social settings.

Short-term regulation of food intake in children, young adults and the elderly

The present study investigated the effects of consuming preloads with different macronutrient and energy contents on subsequent intake and subjective feelings of hunger and satiety in children, young adults and the elderly. 30 Children (4-6 y), 33 young adults (18-26 y) and 24 elderly (61-86 y). A 'preload test meal' design was applied. Subjects were given four different strawberry yoghurt preloads that varied in energy and macronutrient content, or no yoghurt. Children, young adults and elderly consumed 200, 340 and 300 g of the preload, respectively. One yoghurt was low-fat, low-carbohydrate and low in energy (the control; 0.7 MJ/500 g serving), one yoghurt was high-fat and medium in energy (71% of energy (en%) of fat; 2 MJ/500 g serving), one yoghurt was high-carbohydrate and medium in energy (87 en% of carbohydrate; 2 MJ/500 g serving) and the fourth yoghurt was high-fat and high-carbohydrate and high in energy (42 en% of fat and 53 en% of carbohydrate; 3 MJ/500 g serving). Ninety minutes after preload consumption, subjects had an attractive ad libitum lunch-buffet. Energy intake at lunch and subjective feelings of hunger and satiety were analysed. The ability to compensate at lunch did not differ among the three age groups. Compared to the no-preload condition, all children, young adults and elderly ate significantly less after the high-fat and high-carbohydrate yoghurt. The energy compensation observed in the children ranged between -21% and 34%, in the young adults between 15% and 44% and in the elderly between 17% and 23%. Hunger responses were clearly different between young adults and the elderly. Compared to the no-preload condition, the young adults showed larger differences in their appetite ratings than the elderly, indicating that the elderly were less sensitive to the energy content of the preload than the young adults. We conclude that the ability to regulate the food intake within a preload 90 min test meal paradigm did not differ among children, young adults and the elderly. This study was funded by the European Commission as part of project FAIR-CT95-0574.

European strawberry yogurt market analysis with a case studyon acceptance drivers for children in Spain using principalcomponent analysis and partial least squares regression

This study describes a European market analysis of strawberry yogurts using Quantitative Sensory Profiling (QSP), a Givaudan Roure (GR) developed descriptive analysis method. Flavor trends among the products were determined by country, yogurt producer, and marketed age-group using principal component analysis (PCA). From the PCA data generated, new strawberry flavors were developed along the creamy-vanilla, juicy, green-floral, and berry-ripe-banana dimensions. These new flavors, along with the three market leaders for strawberry yogurt in Spain, were analyzed by trained panelists using QSP and hedonically by 160 consumers between the ages of 6 and 16 years. Partial least squares regression (PLS) and correlation analysis identified the positive consumer-liking drivers for strawberry flavor to be vanilla, creamy and balsamic attributes while wild and floral notes decreased liking. Texture attributes of creaminess and homogeneity were positively correlated with consumer liking while syneresis of the product detracted from the acceptability. Two GR developed flavors were significantly preferred over the currently marketed products.

Effect of sweetners (Honey) and storage periods on the organoleptic quality of yoghurt and the survival of in Yoghurt

Seven lots of yoghurt were prepared, two lots each of plain yoghurt, strawberry yoghurt and three lots of honey yoghurt. The yoghurt packages of each type were divided into three groups, The first was subjected for organoleptic examination, the second for determination of pH and the third group was artificially contaminated with Listeria monocytogenes (L. m) Scott A at initial inoculums 2.4 * 10^7 cells / g., for study the survival of bacterium in yoghurts. All examined samples were stored at 4 – 5 C. The results of comparative organoleptic examination, quantitative detection of L. m Scott A as well as pH value of yoghurt were summarized as organoleptically the medium honey yoghurt (6% honey) was the superior (84%), while the inferior tasted samples were strawberry yoghurts (66 – 68%). Bacteriologically : L. monocytogenes Scott A was surviwed twenty twodays with a pH value 3.79 in plain yoghurt, seven days in honey yoghurt (3%honey), the final pH value was 3.86 and six days in honey yoghurt (6&9%honey), the last pH value was 4.18 – 4.21. The survival rate of bacterium in strawberry yoghurt with 3&6% sucrose is nearly similar with that recorded in honey yoghurt. In all cases the listerial count was reduced to 10^2 cells / g, then failed to be detected.

The effect of different concentrations of sugars in two foods (yoghurts and baked beans) on plaque pH

The effect of different concentrations of sugars in two foods (strawberry yoghurt and baked beans) on plaque acidogenicity was investigated using plaque sampling with a 'Beetrode' electrode. Six varieties of yoghurt, four varieties of baked beans and positive and negative control solutions of 10 per cent sucrose and sorbitol, respectively, were tested on six volunteers, selected according to the guidelines agreed at the San Antonio Conference of 1985. Plaque was harvested immediately before a one minute challenge with the test condition and at 5, 10, 15, 20 and 30 minutes thereafter. Parameters investigated were minimum plaque pH reached after a one minute consumption/rinse of the test food or control solution, maximum drop in plaque pH and 'area of the Stephan curve below pH 6.5'. An Acidogenic Potential Index was calculated for each test food and the results did not suggest a linear relationship between sucrose concentration in a food and acidogenic potential.

Lack of effect of taste and nutrition claims on sensory and hedonic responses to a fat-free yogurt

Pleasantness and four sensory attributes of a fat-free strawberry yogurt were rated in three conditions in which different information about the sample was provided: ‘Strawberry yogurt’, ‘Fat-free strawberry yogurt’ and ‘New, tasty fat-free strawberry yogurt’. Seventy-eight subjects were tested in each information condition in a between-subjects design. The effects of information were studied in subject sub-groups based on scoring background scales on 1) Private body consciousness, 2) Food sensations, 3) Concern about food and health, and 4) Frequency of using low-fat products. Information about the sample did not affect pleasantness or sensory ratings. None of the background scales showed a significant interaction effect with information on pleasantness ratings. Sensory ratings of the sample corresponded to subjects' expected ratings of ideal yogurt, which may partly explain the lack of an information effect. Since the quality of the product was as expected, verbal information was not considered. Also, yogurt is already considered a low-fat and healthy product as such and information about its fat-content was irrelevant in this context.

Effect of Sucrose in Breakfast Items on Pleasantness and Food Intake in The Elderly

This study was designed to determine the differences between young and elderly people on the perceived intensity and pleasantness of sucrose in foods, in relation to their food intake. First, a group of 35 young subjects (mean age: 22 ± 2 years) and 29 elderly subjects (mean age: 79 ± 6 years) judged the intensity and the pleasantness of 5 series of breakfast items: orange lemonade, strawberry jam, strawberry yoghurt, chocolate paste, and grain porridge, each with 5 geometrically spaced sucrose concentration levels. On average, the elderly people had a lower slope of the sucrose psychophysical function. Optimal preferred sucrose concentrations were higher for the elderly compared to the young. The second phase in the study concerned the effects of the different optimal sucrose concentrations in foods on food intake. The second experiment dealt with 2 different optimal preferred sucrose concentrations (elderly vs. young subjects) in the food items: orange lemonade, strawberry and blueberry jam, and strawberry and blueberry yoghurt, served during breakfast. A group of 33 young people (mean age: 23 ± 2 years) and 25 elderly subjects (mean age: 82 ± 5 years) participated in a crossover study of 2 5-day (breakfast) treatments. Subjects ate ad lib from these foods and other items such as bread, coffee, and tea. The results showed that the sucrose concentration had no effect on the absolute amount consumed, although total energy intake of the breakfast increased with the higher sucrose foods. No clear difference was found in pleasantness between the 2 breakfasts with the different sucrose concentrations. These findings indicate that a flavor concentration evaluated as being most pleasant by the elderly with the help of small amounts of stimuli (in a lab setting) does not necessarily predict the pleasantness and the food intake behaviour in realistic settings.

Higher-protein foods produce greater sensory-specific satiety

The objectives of this study were to determine if high-protein versions of the same food systems show more sensory-specific satiety than lower-protein versions, and to determine the effect of these protein differences on hunger levels following a meal. Subjects ate a high-protein and a low-protein version of a food system (either strawberry yogurt or a sandwich) as test meals. The high-protein strawberry yogurt test meal consisted of a serving of strawberry yogurt that contained whey protein isolate; the low-protein yogurt test meal consisted of a close-to-commercial strawberry yogurt. The high-protein sandwich meal consisted of a ham sandwich; the low-protein sandwich meal consisted of a bacon sandwich. Subjects tasted small portions of a set of foods (which included a sample of the test meal), and rated their liking of these foods before and after eating a test meal. Sensory-specific satiety occurred for all test meals. The decreases in liking when the high-protein versions of the test meals were eaten were significantly greater than the decreases in liking for the paired low-protein test meals. Higher-protein versions of the test meals also decreased hunger more than the lower-protein versions.

Physiological and subjective responses to food cues as a function of smoking abstinence and dietary restraint

Dietary restraint is a characteristic associated with greater increase in food intake after smoking cessation, and salivation is a marker of physiological responsiveness to food that may be influenced by cessation. The present study examined the effect of brief smoking abstinence (16 h) vs. no abstinence on salivary and subjective responses to food taste cues in women smokers high vs. low in dietary restraint ( n = 10 each). On each of two days (smoking abstinence vs. nonabstinence), salivary volume was assessed during each of 10 trials involving presentation of a small sample of strawberry yogurt. Decline in salivation over trials is indicative of habituation, or reduction in physiological responsiveness to taste cues, and may be a marker of satiety. Subjects also completed self-report measures of hunger, taste liking, desire for cigarette, and emotional arousal during each trial. A 10-min period of ad lib consumption of yogurt ended each session. Results showed significantly elevated salivary response to the first trial of taste exposure in high vs. low restraint women, especially on the smoking day. Moreover, salivary habituation was significantly disrupted by smoking abstinence, especially over the first 5 trials, in high restraint but not low restraint women. High restraint women also reported increasing desire for cigarette and emotional arousal across food taste trials on both days, while low restraint women reported no change in each over trials. There were no differences in ad lib yogurt consumption. These results indicate that brief smoking abstinence attenuates salivary habituation to taste in high restraint women, suggesting a marker for processes responsible for increased food intake after quitting smoking. Repeated exposure to food stimuli may also increase emotional distress in high restraint women smokers, enhancing desire to smoke.

The well-travelled yogurt pot: lessons for new freight transport policies and regional production

Freight transport on roads has increased greatly, especially in the food sector. The growing distances in goods transportation are decisive determinants of environmental and social impacts. There are capacity limits which become evident in the environmental field and in the social field in decreasing quality of life. The concept of a product related transportation analysis which analyses the product- related transportation procedures has been accomplished for a strawberry yogurt. Eight thousand kilometres of roads are used for producing and distributing the examined yogurt. If one 150g strawberry yogurt is purchased in a supermarket in southern Germany, it will have been responsible for moving one lorry over 9.2 metres. So-called "environmental" products are not environmental if the distances are included. A regional product label can identify the origin of the ingredients and the total distance travelled. Suggests product-related transportation analysis can give the basis for such a scheme. (A)

Does fat affect the timing of flavour perception? A case study with yoghurt

Sweetness and sourness intensities of strawberry yoghurts containing 0.1 or 5.2% dairy fat, 6 or 12% sucrose, and 1.1% lactic acid, were rated by 14 assessors in two replications, using the time-intensity procedure. The timing of sweetness and sourness perception in this watercontinuous material was unaffected by the fat content of the samples.

INCORPORATING TASTING INTO A CONJOINT ANALYSIS OF TASTE, HEALTH CLAIM, PRICE AND BRAND FOR PURCHASING STRAWBERRY YOGURT1

ABSTRACTThe objective of this research was to examine some considerations arising from incorporating tasting into a conjoint analysis procedure studying the effects of taste, brand, price and health claim on the buying intent for strawberry yogurt. Specifically, the considerations were: (1) whether people could remember the sensory qualities of the products tasted well enough to re‐identify them in a follow‐up test, and (2) whether their memory of their liking for the products was stable. Two hundred people who purchased and ate strawberry yogurt participated in a three‐part test session. Part 1) They tasted and rated their liking for three yogurt samples and either did or did not take notes on the sensory attributes of the yogurts. Part 2) They rated 27 mock yogurt labels representing 3 brands x 3 taste qualities x 3 prices x 3 health claims on a buying intent scale. Part 3) They rated their liking of the three yogurt samples either from memory or by retasting and they attempted to re‐identify the three yogurt samples. Taking notes improved the proportion of completely correct re‐identifications (75% vs 50%). Liking reratings from memory were as stable as liking reratings by retasting. Taste and health claim had the largest influence on buying intent; brand had little influence on buying intent.

Sensory attributes and acceptance of sucrose and fat in strawberry yoghurts

SummaryYoghurts containing approximately 0.1, 1.5, 3.2, or 5.2% dairy fat were sweetened with 6, 8, 10, or 12% sucrose and flavoured with strawberry jam. the sweetness, fattiness, and sourness of the resulting 16 samples were rated by a laboratory panel (n= 14), and the hedonic responses by a consumer panel (n= 41). As expected, the sweetness and fattiness increased with increasing sucrose and fat contents, respectively. Sucrose enhanced perceived fattiness and fat enhanced sweetness. Sourness was suppressed by both. the sample with 10% sucrose and 3.5% fat received the highest, and the samples with the lowest sucrose and fat contents the lowest, pleasantness ratings. Among the consumers, men preferred high sweetness and fattiness and low sourness, but women did not show any definite tendencies. Although the consumer panel was small, the results demonstrate the importance of segmenting consumers to predict product success.

Abstinence from smoking decreases habituation to food cues

Smokers typically gain weight after cessation due, in part, to increased caloric intake. This increase may be due to enhanced responding to sensory characteristics of foods resulting from a failure to habituate to food cues. To test this possibility, salivation to eight presentations of strawberry yogurt was assessed in male smokers and nonsmokers in two sessions. To test stimulus specificity, on the ninth trial, subjects were presented either more strawberry yogurt or lemon yogurt. Smokers were studied under nonabstinent or abstinent conditions. Salivation for nonabstinent smokers and nonsmokers decreased over presentations, while abstinent smokers showed little change. Nonabstinent smokers and nonsmokers recovered salivation when the new flavor yogurt was presented, and showed greater consumption on the final trial for the different versus same flavor yogurt. Nonabstinent smokers participated in additional within-session smoking sessions to control for withdrawal. Nonabstinent subjects were not different across smoking or not smoking sessions, suggesting the effects are not due to the acute effects of withdrawal.

Sensory Analysis of Dairy Products irradiated with Cobalt‐60 at −78°C

ABSTRACTSensory evaluations by healthy individuals were conducted on cobalt‐60 irradiated retail dairy products which were to be incorporated into the low microbial diets of immunosuppressed patients. Irradiation (40 kGy at ‐78°C) caused little change in product color or texture, but generally there was a decrease in overall acceptability and an increase in off‐flavor and aftertaste. Modified atmosphere packaging (nitrogen, helium, or air) or antioxidant addition (ascorbyl palmitate or a combination of butylated hydroxyanisole and butylated hydroxytoluene) prior to irradiation were effective in preserving specific sensory attributes, which in some cases resulted in improved overall acceptability (helium packed peppermint ice cream; ascorbyl palmitate treated strawberry yogurt bars) when compared to untreated irradiated products.

Salivary pH and glucose after consuming various beverages, including sugar-containing drinks.

Dental erosion is often seen on the lingual tooth surfaces. For this reason tongue pH after consuming orange juice, Coca-Cola (old and new formula), Coca-Cola Light, Jaffa orange beverage, Hart-Sport sport drink, coffee (with and without sugar), beer, sour milk, and strawberry yoghurt was studied in a test panel. The lowest pH values which also remained low for the longest time were observed after consuming Hart-Sport (pH down to 3.80), orange juice, yoghurt, Coca-Cola, and Jaffa, in comparison with coffee (pH down to 5.26), Coca-Cola Light, and beer (p < 0.001). The total glucose concentration in the products and in saliva after consuming them was measured in order to assess the clearance of the products from the mouth. Hart-Sport yielded the highest salivary glucose concentrations (14,000 ppm total glucose) immediately after consuming while yoghurt (4,520 ppm) and coffee with sugar (6,480 ppm) caused the least elevation (p < 0.05). All study products, however, were quickly cleared from the mouth and practically no glucose was left in saliva 30 min after ingestion. Since all the studied products caused lowering of tongue pH below pH 5.5, they have the potential to cause adverse effects on the teeth in patients with impaired salivary function. In the healthy subjects in this study, however, the buffering capacity in the mouth was so strong that not even tongue mucosa could be shown to keep low pH levels a couple of minutes after consumption.