Effects of different prebiotic stabilisers and types of molasses on physicochemical,sensory, colour and mineral characteristics of probiotic set yoghurt

The physicochemical, sensory, properties and mineral profile of probiotic set yoghurts prepared with different prebiotic stabilisers (pectin and guar) at 0.5% (w/v) and different molasses (grape, mulberry and carob) at 10% (v/v) were investigated. Guar‐supplemented yoghurts had the lowest titratable acidity values (P < 0.01) also the highest water‐holding capacity values (P < 0.01). However, guar had a negative effect on gel firmness and sensory properties of yoghurts. The effect of different stabilisers and molasses on colour L* and a*values was statistically significant (P < 0.01). Panelists gave the highest flavour scores to the pectin‐added yoghurts during storage period (P < 0.01).     

Survival and activity of selected probiotic organisms in set-type yoghurt during cold storage

The growth and metabolism of two probiotic organisms (L. acidophilus LAFTI^® L10 and Lactobacillus casei LAFTI^® L26) and a regular yoghurt culture (L. delbrueckii ssp. bulgaricus Lb1466 and Streptococcus thermophilus St1342) were studied in yoghurt containing 0.5%, 1.0%, and 1.5% (w/v) of high amylose corn starch powder (Hi-maize^®) or inulin. Viable cell counts of probiotic organisms, their metabolites and proteolytic activities, and viscosity of the yoghurts were determined during refrigerated storage for 28 d at 4 ^oC. In the presence of inulin, cultures showed better retention of viability (8.0 log cfu g⁻¹) in comparison with that of Hi-maize, which had a reduction by one log cycle. Lower concentrations of 0.5–1.0% Hi-maize improved (P<0.05) the production of propionic acid and also increased proteolytic activity of probiotic organisms substantially. A greater release of free amino acids may have sustained better growth of the organisms in yoghurts. Supplementation with either Hi-maize or inulin increased the viscosity of probiotic yoghurts significantly (P<0.05).     

Encapsulation increases the in vitro bioaccessibility of probiotics in yoghurt

This study examined the encapsulation efficacy of probiotics in yoghurts, product physicochemical properties, the best timing to add encapsulated probiotics during yoghurt manufacturing (before or after fermentation) and their in vitro bioaccessibility. Three different yoghurt types were produced including plain and with encapsulated probiotics added before and after fermentation. A significant (P < 0.05) reduction in total probiotic count was observed in yoghurts containing encapsulated probiotics after 21 days of refrigerated storage. However, the total probiotic count increased during the in vitro colonic fermentation when yoghurts containing encapsulated probiotics were used, indicating increased bioaccessibility of probiotics in the colon.     

Physiochemical,textural, sensory properties and probiotic survivability of Chinese Laosuan Nai (protein‐fortified set yoghurt) using polymerised whey protein as a co‐thickening agent

A new Chinese Laosuan Nai (protein‐fortified set yoghurt) was developed using polymerised whey protein (PWP, 0.4%, w/v) as a co‐thickening agent. The prototype was analysed for physiochemical, textural, sensory properties and probiotic survivability and compared with a commercial sample. Experimental yoghurts were significantly higher in pH, protein content, hardness and viscosity (P < 0.01). Microstructure indicated a uniform and denser protein network. Probiotics remained stable for Bifidobacterium during a 10‐week storage period. Results indicated that polymerised whey protein may be a novel protein‐based co‐thickening agent for making Chinese Laosuan Nai.     

Viability of Lactobacillus acidophilus in rice bran‐enriched stirred yoghurt and the physicochemical and sensory characteristics of product during refrigerated storage

This study was aimed at investigating the fortification of probiotic yoghurt with rice bran to increase nutritional properties of the product. The different levels of rice bran (0.3%, 0.6%, 0.9% and 1.2%) were incorporated into milk. The yoghurt samples were produced after pasteurisation, addition of starter culture and 1% Lactobacillus acidophilus suspension (6 × 10⁸ CFU mL^?1) and incubation. During sample storage in refrigerator, the viability of L. acidophilus, viscosity and physicochemical and sensory properties of product were investigated. Rice bran significantly increased the viability of L. acidophilus (P < 0.05). In addition, all probiotic yoghurts incorporating rice bran indicated higher viscosity and acidity and lower pH and syneresis compared to plain yoghurts. Furthermore, increments in rice bran incorporation levels resulted in a reduction in consumers' sample preferences. In general, the addition of rice bran at a suitable level could increase L. acidophilus viability and improve quality attributes of yoghurt.     

Comparative analysis of physicochemical,rheological, sensory and flavour properties of yoghurts using a new probiotic Bacillus coagulans 13002 with traditional yoghurt starter

Bacillus coagulans 13002 (13002) as a new potential starter was incorporated into the yoghurts for fermentation in this study. We compared three groups of yoghurt, including Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (SL), 13002 (BCS), and 13002 and SL (BCS + SL). Compared with the combination of SL and BCS, the group of BCS + SL exhibited better flavour, higher titratable acidity, cohesiveness and richer volatile compounds, suggesting that the combination of BCS and SL was more efficient to produce the best sensory properties of yoghurt (P < 0.05). The production of volatile compounds in fermentation with and without the addition of BCS was mainly affected by aldehydes, ketones, esters and hydrocarbons, respectively. Furthermore, BCS additions into traditional starters resulted in increasing organic acids and speeding up the usage of sucrose and lactose during the fermentation period of yoghurt. Our study suggested that BCS is a favourable starter supplement for improving the quality of probiotic yoghurts.     

Physicochemical properties of probiotic frozen yoghurt made from camel milk

The purpose of this research was to determine and compare the physicochemical properties of probiotic frozen yoghurts made from camel and cow milks. The results showed that the viscosity of frozen yoghurt made from camel milk was significantly higher (P < 0.05) than that from cow milk. Less fat was destabilised in frozen yoghurt made from camel milk. The frozen yoghurt made from camel milk required more time for melting than that from cow milk. Flavour scores of the frozen yoghurt made from camel milk constituents were significantly lower (P < 0.05) than those made from cow milk.     

Performance of different microbial cultures in potentially probiotic and prebiotic yoghurts from cow and goat milks

Lactobacillus acidophilus or Bifidobacterium animalis subsp. lactis Bb‐12 and green banana pulp were used in order to obtain potentially probiotic and prebiotic yoghurts, which were compared over a 45‐day storage period. Goat milk yoghurts demonstrated probiotic effects up to 45 days of storage. Cow milk yoghurts produced with B. animalis subsp. lactis Bb‐12 showed a probiotic effect reduction during the storage period (1.74 log CFU/g). The type of milk affected the yoghurts’ chemical and physicochemical properties. Sensory acceptance was also affected, where cow milk yoghurts were better accepted than goat milk ones.     

Sensory attributes of low‐fat strawberry yoghurt as influenced by honey from different floral sources,sucrose and high‐fructose corn sweetener

Low‐fat strawberry yoghurts were prepared with each of five alternative sweeteners: sucrose, high‐fructose corn syrup and honey from three different floral sources. A ninety‐nine‐member consumer panel evaluated the yoghurts for flavour, aroma, sweetness and overall acceptance. Degree of liking was scored by the panellists on a nine‐point hedonic scale. Panellists preferred sucrose‐sweetened yoghurts over those sweetened with high‐fructose corn syrup and honey (P < 0.05). Among the honey‐sweetened yoghurts, sage honey was the most liked (P < 0.05), followed by alfalfa‐ and sourwood‐sweetened yoghurts.     

Effects of laurel and myrtle extracts on the sensory,chemical and microbiological properties of vacuum‐packed and refrigerated European eel (Anguilla anguilla) fillets

The effects of extracted natural antioxidant (laurel and myrtle) on the sensory, chemical (TVB‐N, TBARS, PV, FFA and pH) and microbiological (total viable count, psychrotrophic bacteria and Enterbacteriaceae counts) properties of vacuum‐packaged European eel (Anguilla anguilla) stored at 4 ± 1 °C were investigated. The TBARS values of myrtle were significantly lower than that of other groups. The peroxide value was low for European eel treated with myrtle and laurel extract. The FFA‐free fatty acid concentration increased from 0.44 (% oleic acid) (2.03) in the eel during 24 days of storage. The values of pH showed statistically significant (P < 0.05) changes for all groups. The myrtle significantly reduced bacterial growth in fillets (P < 0.05). The microbiological limit of 7 log cfu per gram did not exceed in the treated groups. Data showed that the extracts of myrtle and laurel contain substances that inhibit oxidation of lipids and growth of bacteria in European eel, indicating the potential value of these extracts to extend the shelf life of fish.     

Rheology,spontaneous whey separation,microstructure and sensorial characteristics of probiotic yoghurts enriched with passion fruit fiber

Beyond demonstrated beneficial health attributes, passion fruit rinds are a by-product of the fruit pulp industry, rich in total dietary fiber, particularly pectin. The aim of this study was to evaluate the influence of the addition of passion fruit fiber on the whey formation, rheological parameters, microstructure and sensorial characteristics of probiotic yoghurts. Skim milk bases enriched with 1% of passion fruit fiber or not were heat treated and inoculated with Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, and divided into four groups according to the probiotic strain added — Lactobacillus acidophilus strains L10 and NCFM and Bifidobacterium animalis subsp. lactis strains Bl04 and B94. Fermentations were performed until the pH reached 4.5. Rheological characteristics of yoghurts were determined by a rotational rheometer in two cycles of shear rate ranging from 0 to 15 s^? 1 in both upward and downward curves. Sensorial analysis of passion fruit fiber yoghurts, either without any probiotic or co-fermented by L. acidophilus L10 or B. animalis subsp. lactis Bl04, was evaluated against a control yoghurt without fiber. Photomicrographs of freeze-dried yoghurts were made by field-emission scanning electron microscope (SEM). Thixotropy of enriched yoghurts was higher than that of their respective controls in the two cycles of shear rate. Apparent viscosity was significantly higher in fiber yoghurts co-fermented by the lactobacilli than in their controls at the end of cold storage. Photomicrographs demonstrated that in passion fruit fiber yoghurts the casein gel was more compact and overlaid the fiber, while filaments of exopolysaccharides were more frequent in control yoghurts. Appearance, odor and color of the passion fruit fiber yoghurts received scores as ‘good’, and the intensity of the passion fruit flavor was considered weak by the sensory assessors. Results indicate that the passion fruit fiber is an almost neutral ingredient for the design of new high value-added yoghurt.     

Survival of Lactobacillus casei and functional characteristics of reduced sugar red beetroot yoghurt with natural sugar substitutes

In this study, probiotic gel fermentation and functional characteristics of reduced sugar yoghurt with red beetroot bioactive components and steviol glycosides from Stevia rebaudiana extracts as natural source of noncaloric sweeteners were investigated. A significant increase in Lactobacillus casei viability and fermented gel network and a decrease in syneresis were determined in yoghurt sweetened with steviol glycosides and high content of red beetroot bioactive components such as total phenolics, anthocyanins and total antioxidant capacity (DPPH and FRAP). The survival of L. casei was maintained within probiotic and therapeutic levels (>9 log₁₀ CFU/g), due to the possible prebiotic effect of steviol glycosides and fermentable fibres and phenolic compounds of red beetroot during 28 days of cold storage of the probiotic yoghurts. Colour properties (L*, a*, b*, ΔE*, C*, h*) and such sensory properties as smoothness, sweetness astringency were significantly affected. The highest organic acid content was found in red beetroot enriched yoghurt with stevia, while the most dominant organic acids were butyric, lactic, malic and citric. As a result, it was determined that fermented milk products, which are supported by phytochemical and steviol glycoside interactions, have adequate nutritional effects, high probiotic viability and acceptable sensory properties     

The physicochemical properties of yoghurt supplemented with microencapsulated peanut sprout extract,a possible functional ingredient

This study was designed to determine the physicochemical and sensory properties of yoghurt supplemented with powdered peanut sprout extract microcapsules (PPSEM) (3–10 μm) during storage at 4 °C for 16 days. The releasing rates of the polyphenol, resveratrol, from yoghurts were minimised at lower concentrations of PPSEM (0.25 and 0.5%, w/v). The viscosity decreased gradually with higher concentrations of PPSEM added. In the sensory test, there were significant increases in yellowness, peanut and cooked scores (P < 0.05). Based on the results, it is concluded that the low concentrations (0.25 and 0.50%, w/v) could be used to produce PPSEM‐supplemented yoghurt without significant adverse effects on the physicochemical and functional properties.     

Evaluation of the in vitro cholesterol-lowering activity of the probiotic strain Bacillus coagulansMTCC 5856

Emerging scientific evidence suggests that the supplementation of probiotics may help to reduce/manage blood cholesterol levels in humans. We evaluated the in vitro cholesterol-lowering activity of the probiotic strain Bacillus coagulansMTCC 5856. This probiotic de-conjugated bile salts and liberated deoxycholic acid, confirming its bile salt hydrolase activity. Furthermore, B. coagulansMTCC 5856 also significantly (P < 0.05) reduced cholesterol levels in culture media under growing (48.42%), resting (live but suspended in buffer, 36.47%) and even heat-killed (dead, 8.5%) conditions. Bacillus coagulansMTCC 5856 significantly reduced the cholesterol levels in cholesterol-rich foods, such as egg yolk (39.79%), chicken liver (45.44%) and butter (49.51%), when incubated for 24 h in conditions mimicking the in vivo environment. Bacillus coagulansMTCC 5856 also produced significant (P < 0.05) amounts of propionic acid and butyric acid while fermenting cholesterol-rich foods. The multitudinous ways by which B. coagulansMTCC 5856 reduces cholesterol levels endorses its application in functional food formulations and as a dietary ingredient for the management of hypercholesterolemia, potentially reducing the incidence of coronary heart disease and other related disabilities.     

Quality characteristics of kefir as a carrier for probiotic Lactobacillus rhamnosus GG

Kefir was prepared using kefir grains of different origins (US, Australia and India) and starter culture. The sensory scores for kefir made using starter culture and US kefir grains were significantly higher than for the other samples (P < 0.05). The index of viscosity was significantly higher (P < 0.05) in kefir prepared using Indian kefir grains. Shear stress–shear rate plots indicated yield stress in all kefirs. All samples exhibited shear‐thinning behaviour. The average count of Lactobacillus rhamnosus GG in kefir after incubation was 7.09 log CFU/g. No significant difference (P > 0.05) was observed in quality characteristics in kefir after the addition of LGG, indicating that it could be a potential probiotic carrier.     

Chemical analysis and sensory evaluation of Cheddar cheese produced with Lactobacillus acidophilus,Lb. casei,Lb. paracasei or Bifidobacterium sp.

The sensory properties of probiotic Cheddar cheeses made using Lactobacillus acidophilus 4962, Lb. casei 279, Bifidobacterium longum 1941, Lb. acidophilus LAFTI^® L10, Lb. paracasei LAFTI^® L26 or B. lactis LAFTI^® B94 were assessed after ripening for 9 months at 4 °C. Probiotic cheeses except those with Lb. acidophilus 4962 were significantly different (P<0.05) from the control without any probiotic organism. Acceptability of probiotic cheese with Lb. casei 279 was significantly lower (P<0.05) than that of the control cheese with bitterness and sour-acid taste as the major defects. Concentration of acetic acid in probiotic cheeses was higher (P<0.05) than the control cheese. Vinegary scores did not influence the acceptability of the cheeses (P>0.05). Increased proteolysis in probiotic cheeses did not influence the Cheddary attribute scores (P>0.05). There were positive correlations (P<0.05) between the scores of bitterness and the level of water-soluble nitrogen.     

Amino acids effects on heterocyclic amines formation and physicochemical properties in pan-fried beef patties

The effects of surface application of amino acids on the formation of heterocyclic amines (HCAs) and meat quality properties were evaluated in pan-fried beef patties (230 °C/15 min). Tryptophan, lysine, leucine, and proline at three concentrations, 0.05%, 0.20%, and 0.50% (w/w), were tested. The meat crusts were analyzed for HCA content using liquid chromatography-tandem mass spectrometry. Results showed that surface application of all tested amino acids significantly reduced total HCA content (P < 0.05), and the interaction of amino acid type and concentration significantly affected (P < 0.05) both individual and total HCA formation. Tryptophan at 0.50% reduced total HCAs the most (0.92 ng/g, 93% inhibition), followed by 0.50% lysine (1.94 ng/g, 84% inhibition), while leucine (3.95 ng/g, 64% inhibition) and proline (4.71 ng/g, 56% inhibition) were less effective at 0.50%. In addition, applying amino acids to meat surface significantly influenced (P < 0.05) pH and surface color change of beef crusts; particularly, lysine at 0.20% and 0.50% increased pH and a^* (redness) but reduced b^* (yellowness), while tryptophan and leucine at 0.50% increased L^* (whiteness). No significant effect was observed on cooking loss. Adding amino acids at 0.50% affected (P < 0.05) formation of aldehydes and pyrazines (as the key flavor compounds of fried beef). Overall, the results of this study suggested that adding amino acids to ground beef patties could effectively mitigate mutagenic HCA formation during cooking.     

Consumer acceptability and purchase intent of probiotic yoghurt with added glucose oxidase using sensometrics,artificial neural networks and logistic regression

This research aimed to identify the drivers of acceptance and purchase intent of a probiotic (Bifidobacterium longum BL05) nonflavoured yoghurt supplemented with glucose oxidase, and to model the consumers’ acceptability using sensometrics and artificial neural networks (ANN). Consumers (n = 100) evaluated the degree of liking of yoghurt assays in respect of appearance, aroma, taste, texture and overall linking. Sensometric techniques – multiple linear regression (MLR), partial least squares regression (PLS), principal component regression (PCR) – and ANN were used to model the overall liking. Sensory drivers of global acceptance and purchase intent were also determined using logistic regression (LR). Hierarchical cluster analysis (HCA) identified three consumer segments that presented differences in all sensory attributes evaluated (P < 0.05). The ANN model showed the best performance to predict overall liking, followed by the MLR, PLS and PCR, indicating that taste and texture were the most significant attributes impacting the yoghurts overall liking. In accordance with the logistic models, overall acceptance and purchase intent could be predicted with 81.94 and 85.49% accuracy, respectively. The logistic regression indicated that taste was the attribute that contributed significantly (P < 0.0001) to higher scores for purchase intent and was considered the driver of acceptance.     

Effects of dietary probiotic supplementation on ileal digestibility of nutrients and growth performance in 1‐ to 42‐day‐old broilers

This study was conducted to determine the effects of dietary probiotic supplementation on the ileal digestibilities of nutrients and growth performance in broilers. Two thousand, eight hundred and eighty male broiler chickens at 1 day of age were randomly allotted to eight treatment groups and fed for 6 weeks the maize–soybean meal‐based diets containing 0, 0.2, 0.4 or 0.6% AgiPro A100® (a probiotic) and 0 or 6 ppm flavomycin (an antibiotic). This well‐established antibiotic was used as a positive control for the efficacy of AgiPro A100®. Dietary supplementation with either the probiotic or the antibiotic alone did not affect (P > 0.05) feed intake or average daily gain (ADG) of broilers between days 1 and 42 of life. However, there was a significant antibiotic × probiotic interaction effect (P < 0.05) in increasing ADG during the entire experimental period. Notably, dietary supplementation with the probiotic or the antibiotic consistently improved (P < 0.05) the ileal digestibilities of crude protein and most amino acids in 21‐ and 42‐day‐old chickens. Supplementing the probiotic to broiler diets also improved (P < 0.05) the ileal digestibilities of dry matter, energy, calcium and phosphate in the birds. Collectively, these results indicated that AgiPro A100® is an effective alternative to flavomycin in chicken production. Copyright © 2007 Society of Chemical Industry     

Effect of concentrated plum juice on physicochemical and sensory properties of yoghurt made at bench top scale

Yoghurt with 9% (v/v) of plum juice concentrate (PJC) was stored for 24 days in darkness at 6 °C. Titratable acidity and pH were similar in all samples during storage. The firmness was in the range of 1.7–2.3 N and correlated with total solids of the mixes (R² = 0.982). The sample with PJC and 5.33% (w/v) nonfat dry milk had the highest firmness and the weakest creaminess. The colour in PJC yoghurt was stable during the first seven days of storage. In the ranking test for acceptability, there were no significant differences (P ≤ 0.05) between the yoghurts.