Physicochemical, microbiological and sensory profiles of fermented milk containing probiotic strains isolated from kefir

A two-strain starter culture containing Lactobacillus plantarum CIDCA 83114, a potential probiotic strain isolated from kefir grains, and Streptococcus thermophilus CIDCA 321 was tested for the preparation of a fermented milk product. Kluyveromyces marxianus CIDCA 8154, a yeast with immunomodulatory properties was included to formulate a three-strain starter culture. Supernatants of enterohaemorragic Escherichia coli, shiga-toxin-producing strain, along with a two-strain or a three-strain starter culture were included in the medium of Vero-cell surface cultures. The results demonstrated that these combinations of microorganisms antagonize the cytopathic action of shiga toxins. The cell concentration of Lb. plantarum did not decrease during fermentation, indicating that the viability of this strain was not affected by low pH, nor did the number of viable bacteria change during 21 days of storage in either fermented products. The number of viable yeasts increases during fermentation and storage. Trained assessors analyzed the general acceptability of fresh fermented milks and considered both acceptable. The milk fermented with the two-strain starter culture was considered acceptable after two week of storage, while the product fermented with the three-strain starter culture remained acceptable for less than one week. The main changes in sensory attributes detected by the trained panel were in sour taste, milky taste and also in fermented attributes. The correlation between different sensory attributes and acceptability indicated that the panel was positively influenced by milky attributes (taste, odour, and flavour) as well as the intensity of flavour. In conclusion, the two-strain starter culture would be the more promising alternative for inclusion of that potential probiotic lactobacillus in a fermented milk product.     

Physico-chemical,microbiological, and sensory characteristics of yogurt as affected by various ingredients

l-Glutamine, quercetin, slippery elm bark, marshmallow root, N-acetyl-d-glucosamine, licorice root, maitake mushrooms, and zinc orotate have been reported to help treat leaky gut. The purpose of this research was to explore the impact of these functional ingredients on the physico-chemical, microbiological, and sensory properties of yogurt. The milk from same source was equally divided into 9 pails and the 8 ingredients were randomly assigned to the 8 pails. The control had no ingredient. Milk was fermented to yogurt. The pH, titratable acidity, syneresis, viscosity, color (L*, a*, b*, C*, and h*), Streptococcus thermophilus counts, and Lactobacillus delbrueckii spp. bulgaricus counts of yogurts were determined on d 1, 7, 14, 21, 28, 35, and 42, whereas coliform counts, yeast and mold counts, and rheological characteristics were determined on d 1 and 42. The sensory study was performed on d 3 and particle size of the functional ingredients (powder form) was also determined. When compared with control, the incorporation of slippery elm bark into yogurts led to less syneresis. l-Glutamine increased pH and n′ values (relaxation exponent derived from G′) and lowered titratable acidity values. N-Acetyl-d-glucosamine incorporation resulted in higher n′ and lower titratable acidity values, whereas maitake mushroom led to lower n′ values. Incorporating quercetin increased the growth of L. bulgaricus. Adding maitake mushrooms increased the growth of S. thermophilus but lowered apparent viscosity values, whereas quercetin decreased its S. thermophilus counts. Quercetin decreased L* and a* values but increased b* values, and maitake mushroom increased a* values. Thixotropic behavior increased with the addition of licorice root and quercetin. Adding slippery elm bark, N-acetyl-d-glucosamine, licorice root, maitake mushrooms, and zinc orotate into yogurt did not affect the sensory properties, whereas yogurts with quercetin had the lowest sensory scores. Overall, most of these ingredients did not cause major changes to yogurt properties.     

益生菌Lactobacillus casei Zhang对酸奶风味、质地及感官特性的影响

将益生菌Lactobacillus casei Zhang(Lb. casei Zhang)以1.0×107g-1的添加量与商业酸奶发酵荆YC-X11共同接种进行发酵乳制备.发酵结束(pH=4.5)于4℃冷藏24 h后,分别测定发酵乳样品的酸度、黏度、脱水收缩性、挥发性风味物质、L.delbrueckii subsp.Bulgaricus、S.thermophilus和Lb.casei Zhang活菌数及对其进行感官鉴评.结果表明.Lb.casei Zhang对发酵乳样品的酸度、黏度、脱水收缩性、S.ther-mophilus活菌数无影响(P>0.05),可促进L.delbrueckii subsp.Bulgaricus生长(P<0.05),并使酸奶样品中挥发性风味物质总的质量分数提高17.1%.从而总体上提高发酵乳的感官品质.同时Lb.casei Zhang在发酵乳中具有良好的稳定性.因而益生菌Lb.casei Zhang与商业酸奶发酵剂YC-X11复配进行发酵乳生产具有极大的可行性.     

Physicochemical and microbiological characteristics of camel milk yogurt as influenced by monk fruit sweetener

Camel milk, similar to cow milk, contains all of the essential nutrients as well as potentially health-beneficial compounds with anticarcinogenic, antihypertensive, and antioxidant properties. Camel milk has been used for the treatment of allergies to cow milk, diabetes, and autism. Camel milk helps decrease cholesterol levels in blood and improves metabolism. One of the most desirable food tastes is sweetness. However, the excessive ingestion of sugar negatively affects human health. Monk fruit sweetener is a natural, 0-calorie sweetener with many health-beneficial functions. Monk fruit sweetener helps decrease symptoms of asthma and diabetes, prevents oxidation and cancer, protects the liver, regulates immune function, and lowers glucose levels. Monk fruit sweetener is 100 to 250 times sweeter than sucrose. The objective of this study was to examine the influence of different concentrations of monk fruit sweetener on the physicochemical properties and microbiological counts of drinking yogurt made from camel milk. Camel milk drinking yogurt was produced with 0, 0.42, 1.27, and 2.54 g/L of monk fruit sweetener and stored for 42 d. The physicochemical characteristics and microbiological counts of yogurts were measured at d 1, 7, 14, 21, 28, 35, and 42. For the physicochemical characteristics, pH, titratable acidity, viscosity, and color [lightness-darkness (L*), red-green axis (a*), yellow-blue axis (b*), chroma (C*), and hue angle (h*)] values were evaluated. The counts of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus, coliforms, and yeast and mold were determined. Three replications were conducted. The sweetener addition significantly influenced pH, viscosity, and color (a*, b*, C*, and h*) values. Control samples had significantly higher pH values, lower viscosity, lower b* and C* values, and higher h* values than the samples with 1.27 and 2.54 g/L of monk fruit sweetener. Growth of S. thermophilus, L. bulgaricus, and probiotic culture L. acidophilus was not affected by the incorporation of monk fruit sweetener. Monk fruit sweetener can be added in camel milk yogurts as a health-beneficial 0-calorie sweetener.     

辐照处理对PSE肉的物化、微生物及感官特性影响(英文)

在屠宰厂与农贸市场肉品卫生检验中,常发现以肉色苍白、肉质柔软和切面多汁为特点的生理异常肉,中国称之为"白肌肉"(PSE肉)。PSE肉外观色泽苍白,适口性差,易腐败,因而不受消费者欢迎。为了提高PSE肉的外观颜色及微生物安全性,并考虑因辐照产生的异味及微生物杀菌效果,选择0和4.5kGy的辐照剂量对PSE肉进行处理。之后在4℃下储藏2周,并测定pH、颜色、脂肪过氧化值、微生物安全性及官能特性等指标。结果表明:辐照在改善PSE肉的微生物安全性的同时,还能改善PSE肉色。     

Physicochemical, microbial, and sensory properties of yogurt supplemented with nanopowdered chitosan during storage

This study was carried out to determine the possibility of adding nanopowdered chitosan (NPC) into cholesterol-reduced yogurt to improve the functionality of yogurt and the effects of adding NPC on the physicochemical, microbial, and sensory properties of the products during storage. The pH values and mean lactic acid bacteria counts of NPC-added (0.3 to ∼0.7%, wt/vol) and cholesterol-reduced yogurt ranged from 4.19 to 4.41 and from 4.75 × 10⁸ to 9.70 × 10⁸ cfu/mL, respectively, when stored at 4°C for 20 d, thereby indicating a possibility of prolonging the shelf life of yogurt. In color, the a* and b* values for cholesterol-reduced yogurt were not significantly influenced by the addition of NPC (0.1 to ∼0.7%, wt/vol); however, the L* values significantly decreased with the addition of the greatest concentration (0.7%, wt/vol) of NPC at 0-d storage. The sensory test revealed that the astringency scores significantly increased at 0-d storage when the greatest concentration (0.7%, wt/vol) of NPC was added into cholesterol-reduced yogurt. Based on the data obtained from the current study, it is concluded that concentrations (0.3 to ∼0.5%, vol/vol) of NPC could be used to produce an NPC-added and cholesterol-reduced yogurt without significantly adverse effects on the physicochemical, microbial, and sensory properties.     

Physicochemical,microbiological and sensory characteristics of snacks developed from broken rice grains and turmeric powder

The aim of the present study was to develop extruded snacks from broken rice grains (BRG) and turmeric powder (TP). Different levels of substitution of BRG by TP (0%, 2%, 4%, 8% and 10% w/w) were used. Snacks were processed in a single-screw extruder with three heating zones (41, 61 and 84 °C, respectively), using a helicoidal grooved extrusion sleeve, a 4 mm (diameter) matrix, 3:1 screw compression ratio, screw rotation of 3600 ×  g and a feed rate of 335 g min⁻¹. Snacks were evaluated for their physicochemical, microbiological and sensory characteristics; as well as for the chemical composition, phenolic compounds and the antioxidant capacity of the selected savoury snack formulation. The selected snack, with the physical characteristics closest to the traditional corn product, was obtained with 6% substitution of BRG by TP and was constituted by 7.76% protein, 4.78% lipid, 5.84% dietary fibre, 75.3% available carbohydrates, and 174.75 mg gallic acid equivalent per100 g and 6.52% of DPPH• scavenging capacity. The selected snack was shown to be feasible, once TP is an ingredient that aggregates sensory (colour and taste), nutritional (dietary fibres and total energy value) and functional (antioxidants) values to the BRG-based snack, being an alternative for the production of gluten-free snacks.     

Physicochemical,microbial, and sensory properties of nanopowdered eggshell-supplemented yogurt during storage

This study was carried out to investigate the possibility of adding nanopowdered eggshell (NPES) into yogurt to improve the functionality of yogurt and the effects of adding NPES on the physicochemical, microbial, and sensory properties of the products during storage. The pH and mean lactic acid bacteria counts of NPES-added (0.15–0.45%, wt/vol) yogurt ranged from 4.31 to 4.66 and from 6.56 × 10⁸ to 8.56 × 10⁸ cfu/mL, respectively, whereas these values ranged from 4.13 to 4.44 and 8.46 × 10⁸ to 1.39 × 10⁹, respectively, for the control samples during storage at 5°C for 16 d, which indicates a prolonged shelf-life with NPES-supplemented yogurt. Color analysis showed that the lightness (L*) and position between red and green (a*) values were not significantly influenced by the addition of NPES. However, the position between yellow and blue (b*) value significantly increased with the addition of the concentration (0.45%, wt/vol) of NPES at d 16 of storage. Sensory evaluation revealed that NPES-added yogurts showed a notably less sourness score and a higher astringency score than the control. An earthy flavor was higher in 0.45% NPES-supplemented yogurt compared with the control. Based on the results obtained from the current study, the concentration (0.15 to 0.30%, wt/vol) of NPES can be used to formulate NPES-supplemented yogurt without any significant adverse effects on the physicochemical, microbial, and sensory properties.     

Effects of inulin and sugar levels on the viability of yogurt and probiotic bacteria and the physical and sensory characteristics in probiotic ice-cream

Ice-cream containing probiotic bacteria was produced by mixing fortified milk fermented with probiotic strains with ice-cream mixes with different sugar concentrations (15, 18, 21% (w/w)). Cultures were grown (37 °C, 12 h) in UHT skimmed milk supplemented with or without inulin addition (1% and 2%). The fermented milk was added to the ice-cream mix to a level of 10% w/w.     

Physicochemical and sensory characteristics of milk from goats supplemented with castor or licuri oil

The purpose of this study was to evaluate the influence of castor and licuri palm oils supplemented to milking goats on the physical, chemical, and sensory characteristics of milk. A double Latin square experimental design (5×5) using 10 confined crossbred Moxotó-Alpine goats was performed according to the following treatments: nonsupplemented (control), 3% castor oil, 5% castor oil, 3% licuri oil, and 5% licuri oil. Oils in each treatment were supplemented in the dry matter. Castor oil supplementation reduced the fat content and increased the lactose and density of milk. Considering the sensory analysis, a lower acceptability was observed for milk from goats supplemented with castor oil. On the other hand, licuri oil supplementation led to higher acceptability scores for flavor and odor of goat milk.     

Physicochemical and sensory characteristics of soy yogurt fermented with Bifidobacterium breve K-110, Streptococcus thermophilus 3781, or Lactobacillus acidophilus Q509011

The physicochemical and sensory characteristics of soy yogurt fermented with Bifidobacterium breve K-110, Streptococcus thermophilus 3781, or Lactobacillus acidophilus Q509011 for 36 hr at 37°C were investigated and the soyasaponin metabolites of soy yogurt were measured. L. acidophilus reduced the pH of soy yogurt on day 0 to optimum level. After 36 hr, the Brix dropped to 8.48–9.12°Bx. The viable cell counts of soy yogurts on day 0 were 8.43 to 9.01 log CFU/mL. Among starters, B. breve alone produced soyasapogenol B, although it was not detected in non-fermented soybean. B. breve produced poor sensory scores in all sensory aspects. By mixing B. breve with S. thermophilus and L. acidophilus, the sensory scores of B. breve could be improved. These findings suggest that the mixed culture of S. thermopilus or L. acidophilus with B. breve may be an ideal starter for the preparation of soy yogurt.     

Physicochemical, microbiological and sensory attributes for the characterization of Greek traditional sausages

Physicochemical, microbiological and sensory analyses were performed on 67 samples of Greek traditional sausages. The following physicochemical attributes were recorded: moisture 49.17%±7.05, protein 17.62%±2.67, fat 29.74%±8.02 and ash content 2.99%±0.55, moisture/protein ratio 2.83±0.5. pH value 5.48±0.49, water activity (a(w)) 0.959±0.015, total grill losses 12.81%±5.27 and fat grill losses 9.64%±4.36. The microbial counts, expressed as log(10)cfu/g, were for aerobic plate count 8.22±0.5, lactic acid bacteria 7.45±0.66, Brochothrix thermosphacta 7.02±1.21, pseudomonads 6.88±1.33 and yeasts 5.39±1.03. Mean sensory scores, on a five-point hedonic scale, were 4.46±0.63 for appearance, 4.14±0.63 for firmness, 3.80±0.97 for flavour and 4.12±0.52 for overall quality. The discriminant analysis have shown that, based on their pH and a(w) values, 74.6% of sausages were classified as easily perishable, 19.4% as perishable and 5.9% as shelf-stable. Also, 4.4% of sausages had fat content less than 15%, 23.8% from 15 to 25%, 46.2% from 25 to 35% and 25.3% more than 35%. Principal component analysis has shown that the first two components (PC1 PC2) account for 44.1% of the total variance. PC1 was related to water activity, ash, moisture and fat content, flavour, Br. thermosphacta and pseudomonads count, and to a lesser extent to cross section quality. PC2 was related to aerobic plate count, lactic acid bacteria and moisture content.     

Dry-fermented chicken sausage produced with inulin and corn oil: Physicochemical,microbiological, and textural characteristics and acceptability during storage

This study aimed to evaluate the effect of oil content reduction and the addition of inulin as a partial oil substitute on the physicochemical, microbiological, and textural characteristics and acceptability during the storage (4 °C for 45 days) of dry-fermented chicken sausage produced with corn oil. Reducing the oil content did not influence the characteristics evaluated but tended to produce sausage with a dark reddish coloration. The addition of inulin did not change the physicochemical and microbiological parameters or the acceptability of the products, but resulted in an altered texture profile and a tendency toward lighter and less reddish coloration, similar to products with standard oil content. Fermented chicken sausages produced with standard amounts of corn oil, reduced amounts of corn oil, and inulin as a partial oil replacement remained stable without a significant loss of physical, chemical, microbiological, or sensory attributes during storage at 4 °C for 45 days.