Fortification of sweetened plain yogurt with insoluble dietary fiber

 Seven types of insoluble dietary fiber from five different sources (soy, rice, oat, corn and sugar beet) were used to fortify sweetened plain yogurt. Fiber addition caused an acceleration in the acidification rate of the experimental group yogurts, and most of the fortified yogurts also showed increases in their apparent viscosity. Soy I and sugar beet fibers caused a significant decrease in viscosity due to partial syneresis. In general, fiber addition led to lower overall flavor and texture scores. A grainy flavor and a gritty texture were intense in all fiber-fortified yogurts, except in those made with oat fiber. Oat II fiber gave the best results; differences with controls in terms of flavor quality scores not being statistically significant. The evolution of organic acids during the fermentation and cold storage of control and oat-II-fiber-fortified yogurts showed a similar pattern; only acetic and propionic acids were found in significantly higher amounts in the fiber- fortified product. Received: 27 June 1996/Revised version: 2 September 1996     

Fat free plain set yogurts fortified with various minerals

Seven different minerals (iron, magnesium, zinc, manganese, molybdenum, chromium and selenium) were incorporated separately into the yogurt mixes at 25% of their recommended dietary allowances of 15 mg, 420 mg, 15 mg, 5 mg, 200 μg, 200 μg, 70 μg, respectively. The various attributes studied on the yogurts were viscosity, syneresis, color/lightness (L*), body and texture, appearance and flavor. No significant (P>0.05) difference was observed for viscosity of the yogurts fortified with minerals when compared to the control. Yogurts fortified with iron, selenium and magnesium had better water-holding capacities compared to the control. No significant (P>0.05) differences were observed for flavor and appearance scores of the yogurts fortified with the minerals compared to the control. Fortification of yogurts with these minerals can be accomplished without adversely affecting product characteristics.     

Fat-free plain yogurt manufactured with inulins of various chain lengths and Lactobacillus acidophilus

ABSTRACT:  Inulin is a prebiotic food ingredient that increases the activity of Lactobacillus acidophilus , increases calcium absorption, and is a good source of dietary fiber. The objective was to determine the effect of short, medium, and long chain inulins on the physicochemical, sensory, and microbiological characteristics of fat-free plain yogurt containing L. acidophilus . Inulins of short (P95), medium (GR), and long (HP) chain lengths were incorporated at 1.5% w/w of the yogurt mix. Viscosity, pH, syneresis, sensory properties (flavor, body and texture, and appearance and color), L. acidophilus counts, and color ( L *, a *, and b *) of yogurts were determined at 1, 11, and 22 d after yogurt manufacture. The P95 containing yogurt had a significantly lower pH than the remaining yogurts, higher flavor scores than the yogurt containing HP, and comparable flavor scores with the control. The yogurts containing HP had less syneresis than the control and a better body and texture than the remaining yogurts. Yogurts containing prebiotics of different chain lengths had comparable L. acidophilus counts with each other but higher counts than the control. However, inulins of various chain lengths did not affect viscosity, color, and product appearance. Chain length of prebiotics affected some quality attributes of probiotic yogurts.     

Quality characteristics and consumer acceptance of yogurt fortified with date fiber

Yogurt is considered a healthy food and incorporating dietary fiber will make it even healthier. Date fiber (DF), a by-product of date syrup production, is a good source of dietary fiber. The effect of fortification with DF on fresh yogurt quality was investigated. Acidity, pH, color [L* (lightness), a* (redness), and b* (yellowness) values], texture profile, sensory properties, and consumer acceptance were studied. Control yogurt (without fiber), yogurt fortified with 1.5, 3.0, and 4.5% DF, and yogurt with 1.5% wheat bran (WB) were prepared. Fortification with DF did not cause significant changes in yogurt acidity, although pH was increased. Yogurts fortified with DF had firmer texture (higher hardness values) and darker color (lower L* and higher a*) compared with control or WB yogurts. Consumer test results indicated that the appearance, color, and flavor ratings were significantly affected by fiber fortification. Yogurt fortified with up to 3% DF had similar sourness, sweetness, firmness, smoothness, and overall acceptance ratings as the control yogurt. Sensory ratings and acceptability of yogurt decreased significantly when increasing DF to 4.5% or using 1.5% WB. Flavoring yogurt fortified with 4.5% DF with vanilla did not improve flavor or overall acceptance ratings. Thus, fortifying yogurt with 3% DF produced acceptable yogurt with beneficial health effects.     

Soy Protein Fortification Affects Sensory, Chemical, and Microbiological Properties of Dairy Yogurts

ABSTRACT: Chemical, microbiological, and sensory properties for low fat yogurts fortified with 0,1, 2.5, or 5% soy protein concentrate were determined through 1 mo storage at 5 °C. Yogurts were adjusted to equivalent total solids with nonfat dried milk. Microbiological counts, fermentation time, and final developed acidity were not affected by soy protein. Instrumental viscosity and sensory thickness, soy aroma, and soy flavor increased with soy protein addition (P 0.05). Soy flavor and aroma did not increase with storage time. Yogurt with 5% soy protein was darker, more chalky, and less sweet compared to control yogurt or yogurts with lower concentrations of soy protein (P 0.05). Yogurts with 1 or 2.5% soy protein were most similar to control yogurt.     

Soymilk Yogurt: Sensory Evaluation and Chemical Measurement

Soymilk yogurts with fortifiers, 25% fructose (SOYF), evaporated milk (SOYEM) or nonfat dry milk (SOYN), were compared for stachyose concentration; pH; sour, sweet, and beany flavor; and viscosity. Beaniness was reduced significantly compared to unfermented soymilk; SOYF had the lowest panel score. Sour flavor determined by a trained sensory panel on a 10-point intensity scale was 1.8, 7.8, and 8.0 for SOYF, SOYEM, and SOYN, respectively. Mean sensory viscosity scores for these yogurts were 4.8, 7.9, and 9.0, respectively. Sour flavor and viscosity for SOYF were significantly lower than for other yogurts. No relationships between analytical and sensory measurements of flavor were found; however, instrumental viscosity measurements were linearly related to sensory scores.     

Lutein Is Stable in Strawberry Yogurt and Does Not Affect its Characteristics

ABSTRACT:  The impact of various levels of lutein on the physicochemical, microbiological, and sensory characteristics of yogurt over its shelf life was determined. Nonfat strawberry yogurts were prepared with 0, 0.5, 1.5, and 3.0 mg lutein per 170 g serving (20% overages were included to account for processing losses). The lutein was incorporated prior to homogenization of the yogurt mix. Stability of lutein, viscosity, pH, syneresis, standard plate counts, coliform counts, color (L*, a*, b*), and sensory evaluation (flavor, body and texture, and appearance and color) were measured at weeks 0, 1, 3, and 5 after product manufacture. The interaction effect between levels of lutein and storage time was significant for a* (redness-greenness) values. Lutein levels remained above target throughout the 5-wk storage study. Lutein did not affect viscosity, pH, syneresis, L* (lightness) and b* (yellowness-blueness) values, standard plate counts, coliform counts, flavor, body, texture, appearance, and color scores. These results suggested that lutein was suitable for inclusion in functional yogurts. The skin and eye health benefits provided by lutein can easily be incorporated into yogurt to complement inherent nutritional properties.     

Physicochemical and Organoleptic Properties of Yogurt with Cornelian Cherry Paste

Stirred-type fruit-flavored yogurt was made by adding cornelian cherry paste and sugar at different ratios. The effects of the paste and sugar addition on the physicochemical and organoleptic properties of yogurt were examined. The titratable acidity, pH, viscosity, whey separation, and organoleptic properties of experimental yogurts were determined at weekly intervals for 21 days. Statistically significant differences were found between the control and fruit-flavored yogurts in terms of viscosity and whey separation. The addition of the fruit paste and sugar to yogurt resulted in an increase in the whey separation, and a decrease in the viscosity. During the storage, the values of the titratable acidity, viscosity and whey separations of experimental yogurts increased, while pH of the yogurts decreased significantly (P < 0.01). Yogurt with 10 kg/100 kg fruit paste and 10 kg/100 kg sugar was more acceptable and high scored with respect to overall acceptability value by panelists; however the result was not significant statistically.     

Influence of proteins on the perception of flavored stirred yogurts

Among yogurt dairy components, protein type is known to modify the texture of the products and the volatility of odorous volatile organic compounds. The aim of this study was to investigate the impact of 3 protein ratios (caseinate to total protein) on the sensory properties of 4% fat, strawberry-flavored stirred yogurts. A sensory methodology study was therefore investigated to choose the most efficient method in terms of sensitivity, quantification, and ease with which the panel could distinguish slight differences in olfactory property between the yogurts. Three kinds of product presentation procedures were compared: a monadic presentation, a comparative presentation, and a comparative presentation with a reference. The results showed that the 3 presentation methods emphasized some important texture differences between the yogurts in the same way. However, the comparative procedure with a reference was the only one to reveal clear olfactory property differences between the yogurts. The main effect of protein ratio variation in yogurt concerned the texture properties, which greatly differed between the 3 yogurts and was confirmed by complex viscosity measurements. Olfactory differences between the yogurts were more subtle. Overall, the flavor intensity and the fruity notes were less intense in the yogurts with the high caseinate ratio than in those with the low ratio. This result was in agreement with the physicochemical measurements, which showed a higher retention of a large majority of aroma compounds of the strawberry flavor in the yogurts with a high caseinate ratio.     

复配膳食纤维对低盐香肠食用品质的影响

以猪肉香肠为研究对象,研究低盐条件下（竹盐添加量1.75%）复配膳食纤维（低聚果糖、菊粉、燕麦粉质量比1∶2∶1）完全替代淀粉对低盐香肠食用品质的影响。以感官评价、质构特性、蒸煮损失和色泽等食用品质为评价指标,确定低盐条件下复配膳食纤维的最佳添加量,并与1.75%精制盐淀粉香肠、复配膳食纤维香肠比较食用品质差异。结果表明：添加8%复配膳食纤维的竹盐香肠总体可接受性最高,香肠组织致密、切面整齐、呈肉红色、香味浓郁、鲜美多汁、质地柔软且富有弹性;复配膳食纤维添加量为5%、11%、14%时,香肠总体可接受性相对较差,风味稍差;复配膳食纤维的添加量由5%增加至14%,蒸煮损失由11.28%减小至8.38%;用复配膳食纤维替代淀粉,香肠质地变软,风味、口感评分增加,蒸煮损失由5.71%增加至9.07%。综上可知,复配膳食纤维添加量影响香肠食用品质,添加8%复配膳食纤维的竹盐香肠食用品质最高。     

燕麦麸添加量对燕麦麸猪肉丸品质的影响

为采用燕麦麸糊替代猪肉丸中部分脂肪以开发最佳的低脂肉丸,本实验对不同燕麦麸添加量对传统猪肉丸的感官品质、色泽、质构、基本成分、风味物质及氧化程度的影响进行研究,从而为低脂燕麦麸猪肉丸的开发提供可行性建议。结果表明：当燕麦麸添加量为3.09%时,燕麦麸猪肉丸感官总评最高。随燕麦麸添加量增加,燕麦麸猪肉丸硬度、咀嚼性显著降低;亮度逐渐减小,红度与黄度增加;脂肪含量显著减少,粗纤维、蛋白质、水分含量增加。根据电子鼻及气相色谱-质谱分析发现,5 组样品的风味差异明显且脂肪氧化产物的含量降低;高效液相色谱分析显示,燕麦麸猪肉丸核苷酸含量并无显著差异,而氨基酸总量显著下降;过氧化值逐渐降低,但硫代巴比妥酸值却增加。综上,燕麦麸添加量对产品各方面的品质具有不同影响,因此,选择适当的燕麦麸添加量（3.09%）能保证燕麦麸猪肉丸综合品质最佳。     

Exploiting blackcurrant juice press residue in extruded snacks

Extrusion process was developed to exploit blackcurrant juice press residues from industrial side-streams. Press residues obtained from conventional enzymatic pressing, with high content of fiber and seed oil, and novel non-enzymatic juice processing, with high content of sugars, fruit acids and anthocyanins, were extruded with barley flour, oat flour or oat bran. The recipes consisted of blackcurrant press residues (30%), cereal materials (40%) and potato starch (30%) and small amount of sugar and salt. When compared to enzymatic press residue and oat bran, the novel non-enzymatic press residue extruded with barley or oat flour had higher expansion, lower hardness and density, higher redness (a*), lower pH, and higher contents of fructose, glucose and fruit acids, all contributing positively to liking of texture, appearance, and flavor as well as berry-like experience. These characteristics were obtained with more gentle processing parameters, consisting of a lower total mass flow, screw speed and barrel temperature. Female consumers gave lower ratings in flavor, appearance and overall pleasantness for blackcurrant snacks than males. The study presented a sustainable way of utilizing industrial press residues from different processes of berry juice pressing for production of healthy snacks and breakfast cereals.     

Quality attributes of yogurt with Lactobacillus casei and various prebiotics

The objective was to determine the effect of chain length of inulins on the characteristics of fat-free plain yogurt manufactured with Lactobacillus casei. Probiotic fat-free plain yogurts were manufactured using Streptococcus thermophilus, Lactobacillus bulgaricus and L. casei. The treatments were inulins of short (P95), medium (GR) and long (HP) chain lengths. The inulins were incorporated at a concentration of 1.5 g/100 g yogurt mix. Inulins of various chain lengths did not affect viscosity, L*, a*, b* and appearance of yogurts manufactured with L. casei. Yogurt with HP had less syneresis compared to the control, while yogurt with P95 had syneresis comparable to the control. Yogurt with P95 had a significantly lower pH than the control, while the pH of the yogurts with other treatments was not different from the control. Flavor scores of the control were comparable to yogurt with P95. The flavor scores for yogurts with P95 were significantly higher than for yogurts with HP. The yogurts with HP had better body and texture compared to the control and P95. Chain length of prebiotics affected some characteristics of the yogurts.     

Calcium Supplementation and Processing Variable Effects on Orange Juice Quality

Untreated, pectinesterase treated, low pulp, and pectinase treated orange juices were fortified to 20% RDA of calcium with calcium carbonate or calcium phosphate/lactate (75/25). Neither calcium supplement adversely affected flavor, cloud density, settling pulp, or viscosity in untreated, low pulp, or pectinase treated juices. PME exposed orange juice held 4 hr before pasteurization and calcium supplementation had less cloudy density, increased viscosity and more settling pulp. Calcium carbonate fortified PME exposed and pectinase treated juices had lower flavor scores, while calcium phosphate suspensions caused slightly lower color scores of all juices.     

Soybean hull polysaccharides affect the physicochemical properties and lactic acid bacteria proliferation in plant-based yogurt

As a by-product of soybean processing, soybean hulls contain soybean hull polysaccharides (SHPS). This study aims to develop a plant-based yogurt with SHPS addition and assess the consequences of SHPS on the physicochemical properties and growth of lactic acid bacteria (LAB) in yogurts. The study investigated the water holding capacity (WHC), microstructure, rheological properties, texture, pH, organoleptic attributes, volatile compounds, flavor profile, and LAB population. The findings reveal that the addition of SHPS significantly impacted these properties. SHPS improved the physicochemical properties, increased the level of flavor compounds, and improved the organoleptic properties of yogurt. Yogurt with 0.6% SHPS demonstrated superior WHC, texture, rheological properties, and the highest organoleptic evaluation scores. However, when SHPS additions exceeded 0.6%, WHC, texture, and rheological properties of the yogurts decreased. Furthermore, SHPS-added yogurts contained more LAB compared to yogurt without SHPS. LAB grew better in media with SHPS than in media without glucose. Streptococcus thermophilus grew best among the LAB strains. This study highlights the potential of SHPS in yogurt production and its promising applications in fermented food products.     

Sugar reduction in chocolate compound by replacement with flours containing small insoluble starch granules

Consumer concern about intake of added sugars has increased commercial demand for sugar-reduced chocolates. However, substitution with high-potency sweeteners is not possible as sugar serves as an important bulking agent. Here, we investigated replacement of sucrose in chocolate compound with oat or rice flours, with starch granules smaller than 10 µm, focusing on texture, sweetness, and acceptability. In Study 1, six chocolates were made: a control with 54% sucrose, four sucrose-reduced versions (reductions of 25% or 50%, using either oat or sweet rice flour), and one 54% sucrose chocolate with reduced refining time. These chocolates were compared in a Difference from Control (DFC) test in a within-subject design, with and without nose clips. Particle size distribution, yield stress, and plastic viscosity were measured. Chocolates with 25% sucrose reduction by either sweet rice or oat flour (or reduced refining time) were not significantly different from the blind control (p > 0.05), regardless of nose clip use. In open-ended comments, participants reported differences in rice-flour-containing chocolates were due to a chalkier texture, while oat-flour-containing chocolates were described as smoother, softer, and creamier. DFC scores from the chocolates were positively correlated with plastic viscosity and negatively correlated with yield stress. In Study 2, 25% reduced sugar chocolates made with rice flour were liked significantly less than control, but the oat flour sample did not differ from control. Collectively, these results suggest up to 25% of sucrose in chocolate can be replaced with oat flour without negatively affecting texture or consumer acceptance.     

Potential for β-Cyclodextrin as Partial Fat Replacer in Low-fat Foods

ABSTRACT: Headspace gas chromatography analysis of a series of flavored milks and yogurts indicated that addition of β-cyclodextrin to nonfat products results in flavor-release profiles similar to those of corresponding higher-fat-content products, suggesting the potential for this material as a partial fat replacer. A follow-up sensory evaluation study was carried out with a number of yogurts and salad dressings. Although addition of β-cyclodextrin to nonfat yogurt did not result in a product more like a low-fat product (based on flavor and texture), flavor profiles of nonfat Italian-style and ranch-style dressings were indeed more similar to the corresponding full-fat products. Therefore, the use of β-cyclodextrin as a partial fat replacer in salad dressings appears worthy of further study.     

高密度菌种发酵酸奶品质变化研究

为了比较高密度与非高密度两种菌种发酵的酸奶的感官性状及理化指标,对两种菌种发酵酸奶的菌落总数、pH值、黏度、稳定性、滴定酸度、保水性进行对比,并采用气相色谱-质谱（GC-MS）法对挥发性风味物质进行对比。结果表明,高密度菌种发酵制备的酸奶菌落总数（8.23～8.70 lgCFU/mL）、滴定酸度（88～92 °T）及感官评分（76～78分）分别高于非高密度菌种发酵制备的酸奶（7.98～8.53 lgCFU/mL）、（82.3～91.1 °T）、（68～70分）,而二者pH值、黏度、稳定性、保水性相差不大。高密度与非高密度菌种发酵酸奶中共检测风味化合物分别为24、20种,其中酯类物质的相对含量分别为0.52%、0.41%,酮类物质的相对含量分别为0.048%、0.012%。因此,高密度菌种发酵所得酸奶品质指标较优。