Enrichment of set yoghurt with flaxseed oil, flaxseed mucilage and free or encapsulated Lacticaseibacillus casei: Effect on probiotic survival and yoghurt quality attributes

This study was intended to develop yoghurt products incorporated with flaxseed mucilage (FM), flaxseed oil (FO) and free or encapsulated Lacticaseibacillus casei probiotics. FM (0.9%) and sodium alginate (2%) were used as wall materials for encapsulating L. casei. Different physicochemical and sensory properties of the yoghurt, as well as the L. casei survival, were determined during 21 days of storage at 4 °C. Based on the results, FM showed a stimulatory effect on the growth of probiotics and thus, significantly decreased the Log reduction of the probiotics during storage (P < 0.05). Moreover, encapsulating probiotics significantly decreased the Log reduction during storage in comparison with the free bacteria (P < 0.05). Incorporating FM and free probiotics significantly increased the acidity and decreased the pH of the samples; while encapsulating L. casei successfully prevented the acidity increment in probiotic fortified yoghurt products (P < 0.05). The addition of FM significantly improved the water holding capacity of the yoghurt (P < 0.05). Incorporating either free L. casei, FO or FM significantly reduced the flavor and overall acceptance scores; while, the addition of L. casei in the encapsulated form did not significantly alter the overall acceptance scores of the yoghurt samples (P < 0.05).

Pre- and post-diagnostic dairy intake in relation to recurrence and all-cause mortality in people with stage I-III colorectal cancer

PURPOSE

Higher dairy consumption is associated with a lower risk of colorectal cancer (CRC), but no studies thus far have investigated its relation with recurrence in CRC. Few studies have investigated total dairy in relation to mortality in CRC, and yielded inconsistent results.

METHODS

In this prospective cohort study, people newly diagnosed with stage I-III CRC filled out a food frequency questionnaire at diagnosis (n = 1812) and six months after diagnosis (n = 1672). We examined associations between pre- and post-diagnostic intake of total dairy, low-fat dairy, high-fat dairy, milk, yoghurt, and cheese with recurrence and all-cause mortality using multivariable Cox proportional hazard models and restricted cubic splines (RCS).

RESULTS

A total of 176 recurrences and 301 deaths occurred during a median follow-up of 3.0 and 5.9 years, respectively. Before diagnosis, a higher low-fat dairy intake was associated with a lower risk of recurrence (HRQ4vsQ1: 0.42, 95% CI 0.26-0.67; PRCS: 0.008) and all-cause mortality (HRQ4vsQ1: 0.58, 95% CI 0.41-0.81; PRCS < 0.001), whereas a higher high-fat dairy consumption tended to be associated with an increased all-cause mortality risk (HRQ4vsQ1: 1.41, 95% CI 0.98-2.01; PRCS: 0.030). After diagnosis, only the associations between low- and high-fat dairy in relation to all-cause mortality remained.

CONCLUSIONS

This study demonstrated that higher pre- and post-diagnostic intakes of low-fat dairy were associated with a reduced all-cause mortality risk in people with stage I-III CRC, whereas higher intakes of high-fat dairy were associated with an increased all-cause mortality risk. Also, a higher pre-diagnostic low-fat dairy intake was associated with a reduced risk of recurrence.

TRIAL REGISTRATION

Clinical Trials.gov identifier: NCT03191110.

Dairy intake and risk of hip fracture in prospective cohort studies: non-linear algorithmic dose-response analysis in 486 950 adults

Previous studies on the relationship between dairy consumption and hip fracture risk have reported inconsistent findings. Therefore, we aimed to conduct an algorithmically driven non-linear dose-response meta-analysis of studies assessing dairy intake and risk of developing incident hip fracture. Meta-analysis from PubMed and Google Scholar searches for articles of prospective studies of dairy intake and risk of hip fracture, supplemented by additional detailed data provided by authors. Meta-regression derived dose-response relative risks, with comprehensive algorithm-driven dose assessment across the entire dairy consumption spectrum for non-linear associations. Review of studies published in English from 1946 through December 2021. A search yielded 13 studies, with 486 950 adults and 15 320 fractures. Non-linear dose models were found to be empirically superior to a linear explanation for the effects of milk. Milk consumption was associated with incrementally higher risk of hip fractures up to an intake of 400 g/d, with a 7 % higher risk of hip fracture per 200 g/d of milk (RR 1⋅07, 95 % CI 1⋅05, 1⋅10; P < 0⋅0001), peaking with 15 % higher risk (RR 1⋅15, 95 % CI 1⋅09, 1⋅21, P < 0⋅0001) at 400 g/d versus 0 g/d. Although there is a dose-risk attenuation above 400 g/d, milk consumption nevertheless continued to exhibit elevated risk of hip fracture, compared to zero intake, up to 750 g/d. Meanwhile, the analysis of five cohort studies of yoghurt intake per 250 g/d found a linear inverse association with fracture risk (RR 0⋅85, 95 % CI 0⋅82, 0⋅89), as did the five studies of cheese intake per 43 g/d (~1 serving/day) (RR 0⋅81, 95 % CI 0⋅72, 0⋅92); these studies did not control for socioeconomic status. However, no apparent association between total dairy intake and hip fracture (RR per 250 g/d of total dairy = 0⋅97, 95 % CI 0⋅93, 1⋅004; P = 0⋅079). There were both non-linear effects and overall elevated risk of hip fracture associated with greater milk intake, while lower risks of hip fracture were reported for higher yoghurt and cheese intakes.

A chemical study of yoghurt produced under isostatic pressure during storage

Yoghurt fermented under sub-lethal high pressure (10, 20, 30 and 40 MPa at 43 °C), and afterward placed under refrigeration (4 °C for 23 days) was studied and compared with yoghurt fermented at atmospheric pressure (0.1 MPa). For a deeper analysis, metabolite fingerprinting by nuclear magnetic resonance (NMR), sugars and organic acids assessment by high performance liquid chromatography (HPLC), total fatty acids (TFA) determination and quantification by gas chromatography with a flame ionization detector (GC-FID) were performed. Metabolomic analyses revealed that only 2,3-butanediol, acetoin, diacetyl and formate vary with the increase of pressure and probable relation with pressure influenced diacetyl reductase, acetoin reductase and acetolactate decarboxylase. Yoghurts fermented at 40 MPa had the lowest content in lactose (39.7 % of total sugar reduction) and the less content in TFA (56.1 %). Further research is of interest to understand more about fermentation processes under sub-lethal high pressure.

Iodine fortification of plant-based dairy and fish alternatives: the effect of substitution on iodine intake based on a market survey in the UK

Milk, dairy products, and fish are the main sources of iodine in the UK. Plant-based products are increasingly popular, especially with young women, which may affect iodine intake as they are naturally low in iodine; this is concerning as iodine is required for fetal brain development. We, aimed to (i) assess the iodine fortification of products sold as alternatives to milk, yoghurt, cheese and fish through a cross-sectional survey of UK retail outlets in 2020, and (ii) model the impact of substitution with such products on iodine intake, using portion-based scenarios. We identified 300 products, including plant-based alternatives to: (i) milk (n 146); (ii) yoghurt (n 76); (iii) cheese (n 67) and (iv) fish (n 11). After excluding organic products (n 48), which cannot be fortified, only 28 % (n 29) of milk alternatives and 6 % (n 4) of yoghurt alternatives were fortified with iodine, compared with 88 % (n 92) and 73 % (n 51), respectively, with Ca. No cheese alternative was fortified with iodine, but 55 % were fortified with Ca. None of the fish alternatives were iodine fortified. Substitution of three portions of dairy product (milk/yoghurt/cheese) per day with unfortified alternatives would reduce the iodine provided by 97·9 % (124 v. 2·6 µg) and substantially reduce the contribution to the adult intake recommendation (150 µg/d; 83 v. 1·8 %). Our study highlights that the majority of plant-based alternatives are not iodine fortified and that the use of unfortified alternatives put consumers at risk of iodine deficiency.

Effect of set-type yoghurt supplemented with the novel probiotic Lantiplantibacillus plantarum 200655 on physicochemical properties and the modulation of oxidative stress-induced damage

The present study developed a functional yoghurt supplemented with Lantiplantibacillus plantarum 200655 and evaluated its physicochemical properties and antioxidant activities. Yoghurt samples were prepared using commercial starter cultures and probiotics and grouped as follows: control sample without probiotics (C), GG (supplemented with Lacticaseibacillus rhamnosus GG), R (supplemented with L. plantarum KCTC 3108), and S (supplemented with L. plantarum 200655). The GG, R, and S samples had shorter fermentation time compared with the C sample. Lactic acid bacteria count, pH, and titratable acidity were similar in all samples during refrigerated storage. However, the GG, R, and S samples showed increased viscosity and water holding capacity (WHC), and decreased syneresis. The S sample had no adverse effect on organoleptic properties. Furthermore, the S sample had the highest antioxidant activity and significantly inhibited LPS-induced oxidative stress in intestinal cells. These findings suggest the potential use of L. plantarum 200655 in dairy products with therapeutic benefits.

Comparison of physicochemical properties and volatile flavor compounds of plant-based yoghurt and dairy yoghurt

The aim of this study was to investigate and compare the physicochemical characteristics and volatile flavor compounds of three kinds of yoghurt made from reconstituted milk, soy drink and oat drink. The results showed that with the same fermentation ending pH of 4.5, reconstituted yoghurt had the highest titratable acidity mainly due to the highest buffering capacity and microbial counts (LAB). The textural and water holding capacity (WHC) parameters revealed that soy-based yoghurt had the highest firmness, consistency and WHC, indicating more rigid gel was formed. Meanwhile, rheological analysis showed soy-based yoghurt owned higher G' and G'' values and higher stability against external stress, demonstrating that more and stronger interactions between soy proteins were built during fermentation. The confocal laser scanning microscopy (CLSM) image witnessed that soy-based yoghurt had the densest and finest network, while oat-based yoghurt had much coarser and looser structure, which was consistent with the lowest firmness and G' value for oat-based yoghurt. In terms of color, reconstituted yoghurt was the lightest and oat-based yoghurt showed more reddish and yellowish. The main volatile flavor compounds in all yoghurts were ketones, while aldehydes contributed more in soy and oat yoghurt. PCA plot showed that volatile flavor compounds of reconstituted yoghurt and oat-based yoghurt were relatively similar, while soy-based yoghurt was much more different with high OAVs of hexanal, 1-octen-3-one, 1-octen-3-ol and 2-octenal. This study supplied a theoretical basis and an improvement direction for the better development of healthier plant-based yoghurt similar to dairy yoghurt.

Encapsulation of soy isoflavone extract by freeze drying, its stability during storage and development of isoflavone enriched yoghurt

Soybean is a natural source of isoflavone. Its extract has a bitter and astringent taste and undergoes through oxidative deterioration. The study aimed at encapsulation of isoflavone extract using different carrier material through freeze drying. Maltodextrin, β-cyclodextrin, and tapioca starch were employed in 1:3 while sodium alginate and carboxymethyl cellulose in 1:1.25 as extract to carrier material ratio for encapsulation. Carrier material reflected significant (< 0.05) effect on encapsulation efficiency, isoflavone content and morphology of encapsulated extract. Maltodextrin was selected as the best material for encapsulation of isoflavone extract reflecting significantly higher encapsulation efficiency along with homogenous coating on the particle surface as examined through SEM. The band stretching in FTIR analysis also indicates the retention of functional groups after encapsulation. The encapsulated extract packed in ambered glass vials can be stored safely for a period of 6 months with a higher withholding of isoflavones under refrigerated conditions. Furthermore, encapsulated isoflavone extract was incorporated in yoghurt @ 50 mg isoflavone which improved its functional and sensory properties. About 96.83% of isoflavone was retention in yoghurt containing encapsulated extract compared to yoghurt having extract without encapsulation.

Characterization of exopolysaccharide produced by Levilactobacillus brevis HDE-9 and evaluation of its potential use in dairy products

The bacterial strain HDE-9 was isolated from sauerkraut and identified as Levilactobacillus brevis. An exopolysaccharide (EPS) was isolated and purified from L. brevis HDE-9, and a preliminary investigation of its structural characteristics and biological activity was conducted. The molecular weight of the EPS was >1.0 × 10⁶ Da. Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy revealed that the EPS was composed of α-(1 → 6) linked d-glucopyranose units. X-ray diffraction (XRD) data on the EPS revealed its non-crystalline amorphous structure. Scanning electron microscopy (SEM) of the EPS revealed a smooth surface with sheet structures. The EPS exhibited the high value in thermal stability, water solubility, water holding capacity (WHC), and emulsification activity (EA). The water contact angle of the EPS revealed relatively high hydrophobicity in the presence of sucrose. The EPS also showed a strong milk solidification capacity in a dose-dependent manner. The EPS could significantly improve the texture of yoghurt, indicating its potential application as a functional starter in the production of fermented dairy products.

Characterization of exopolysaccharide produced by Levilactobacillus brevis HDE-9 and evaluation of its potential use in dairy products

The bacterial strain HDE-9 was isolated from sauerkraut and identified as Levilactobacillus brevis. An exopolysaccharide (EPS) was isolated and purified from L. brevis HDE-9, and a preliminary investigation of its structural characteristics and biological activity was conducted. The molecular weight of the EPS was >1.0 × 10⁶ Da. Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy revealed that the EPS was composed of α-(1 → 6) linked d-glucopyranose units. X-ray diffraction (XRD) data on the EPS revealed its non-crystalline amorphous structure. Scanning electron microscopy (SEM) of the EPS revealed a smooth surface with sheet structures. The EPS exhibited the high value in thermal stability, water solubility, water holding capacity (WHC), and emulsification activity (EA). The water contact angle of the EPS revealed relatively high hydrophobicity in the presence of sucrose. The EPS also showed a strong milk solidification capacity in a dose-dependent manner. The EPS could significantly improve the texture of yoghurt, indicating its potential application as a functional starter in the production of fermented dairy products.

Yoghurt consumption is associated with changes in the composition of the human gut microbiome and metabolome

BACKGROUND

Yoghurt contains live bacteria that could contribute via modulation of the gut microbiota to its reported beneficial effects such as reduced body weight gain and lower incidence of type 2 diabetes. To date, the association between yoghurt consumption and the composition of the gut microbiota is underexplored. Here we used clinical variables, metabolomics, 16S rRNA and shotgun metagenomic sequencing data collected on over 1000 predominantly female UK twins to define the link between the gut microbiota and yoghurt-associated health benefits.

RESULTS

According to food frequency questionnaires (FFQ), 73% of subjects consumed yoghurt. Consumers presented a healthier diet pattern (healthy eating index: beta = 2.17 ± 0.34; P = 2.72x10-10) and improved metabolic health characterised by reduced visceral fat (beta = -28.18 ± 11.71 g; P = 0.01). According to 16S rRNA gene analyses and whole shotgun metagenomic sequencing approach consistent taxonomic variations were observed with yoghurt consumption. More specifically, we identified higher abundance of species used as yoghurt starters Streptococcus thermophilus (beta = 0.41 ± 0.051; P = 6.14x10-12) and sometimes added Bifidobacterium animalis subsp. lactis (beta = 0.30 ± 0.052; P = 1.49x10-8) in the gut of yoghurt consumers. Replication in 1103 volunteers from the LifeLines-DEEP cohort confirmed the increase of S. thermophilus among yoghurt consumers. Using food records collected the day prior to faecal sampling we showed than an increase in these two yoghurt bacteria could be transient. Metabolomics analysis revealed that B. animalis subsp. lactis was associated with 13 faecal metabolites including a 3-hydroxyoctanoic acid, known to be involved in the regulation of gut inflammation.

CONCLUSIONS

Yoghurt consumption is associated with reduced visceral fat mass and changes in gut microbiome including transient increase of yoghurt-contained species (i.e. S. thermophilus and B. lactis).

Simultaneous preconcentration and determination of sulfonamide antibiotics in milk and yoghurt by dynamic pH junction focusing coupled with capillary electrophoresis

A dynamic pH junction was used in capillary electrophoresis (CE-DAD) to on-line preconcentrate, separate, and determine trace amounts of sulfonamide antibiotics (SAs) in milk and yoghurt samples in this study. A sample matrix with 0.15% acetic acid and 10% methanol (MeOH) at a pH of 4.0, and a background electrolyte (BGE) that contained 35 mM sodium citrate with 10% MeOH at a pH of 8.5, and an acidic barrage of 0.4% acetic acid with 10% MeOH at a pH of 2.5 were utilised to achieve a stacking effect for SAs through a dynamic pH junction. Under optimised conditions, the proposed preconcentration method showed good linearity (30-500 ng/mL, r² ≥ 0.9940), low limits of detection (LODs) of 4.1-6.3 ng/mL, and acceptable analytes recovery (81.2-106.9%) with relative standard deviations (RSDs) within 5.3-13.7 (n = 9). The limits of quantification (LOQs) were below the maximum residue limit approved by the European Union (EU) in this type of matrices. Sensitivity enhancement factors of up to 129 were reached with the optimised dynamic pH junction using CE with a diode array detector (DAD). The method was used to determine SAs in fresh milk, low-fat milk, full-cream milk, and yoghurt samples.

High level expression of a xyloglucanase from Rhizomucor miehei in Pichia pastoris for production of xyloglucan oligosaccharides and its application in yoghurt

The xyloglucanase gene (RmXEG12A) from Rhizomucor miehei CAU432 was successfully expressed in Pichia pastoris. The highest xyloglucanase activity of 25,700 U mL^-1 was secreted using high cell density fermentation. RmXEG12A was optimally active at pH 7.0 and 65 °C, respectively. The xyloglucanase exhibited the highest specific activity towards xyloglucan (7915.5 U mg^-1). RmXEG12A was subjected to hydrolyze tamarind powder to produce xyloglucan oligosaccharides with the degree of polymerization (DP) 7-9. The hydrolysis ratio of xyloglucan in tamarind powder was 89.8%. Moreover, xyloglucan oligosaccharides (2.0%, w/w) improved the water holding capacity (WHC) of yoghurt by 1.1-fold and promoted the growth of Lactobacillus bulgaricus and Streptococcus thermophiles by 2.3 and 1.6-fold, respectively. Therefore, a suitable xyloglucanase for tamarind powder hydrolysis was expressed in P. pastoris at high level and xyloglucan oligosaccharides improved the quality of yoghurt.

The association between dairy products and psychological disorders in a large sample of Iranian adults

BACKGROUND

Dairy products contain certain nutrients that are useful in mental disorders. This study aimed to assess the associations between dairy products and psychological disorders in a large sample of Iran, a Middle Eastern country.

METHODS

This cross-sectional study was undertaken on 7387 adults. Data on dietary intakes were obtained using a validated Food Frequency Questionnaire. Psychological health was assessed by the Iranian validated version of depression, anxiety, and stress scale 21. Multivariable logistic regression analysis was performed to analyze the association between dairy intake and psychological disorders.

RESULTS

After adjustment for potential confounders, total milk consumption (OR for the highest vs. lowest tertile: 0.73, 0.58-0.92) and total yogurt consumption (0.78, 0.62-0.97) were associated with decreased odds of depression. An inverse relationship was found between total dairy (0.73, 95% CI 0.590.91), total milk (0.72; 0.58-0.88), kashk (0.79, 0.65-0.96), and yogurt drink (0.80, 95% CI 0.65-0.98) consumption and anxiety symptoms. Higher intake of cheese was related to greater odds of stress (1.52, 1.02-2.26). No association was found between the consumption of high-fat dairy, low-fat dairy, low-fat milk, low-fat yogurt, high-fat yogurt, cheese, kashk, yogurt drink, and depression. Also, there is no association between dairy products and stress symptoms. This association was significant among men and women and high-fat and low-fat products in the total adjusted stratified analysis models.

CONCLUSIONS

Findings of this study revealed that both high-fat and low-fat dairy products are associated with a reduced prevalence of psychological disorders. Still, more prospective studies are required to confirm these associations.

In vitro gastrointestinal resistance of Lactobacillus acidophilus in some dairy products

In this study, different dairy products such as ice cream, yoghurt, white pickled cheese, and fermented acidophilus milk were manufactured by using either Lactobacillus acidophilus DSM 20,079 or Lactobacillus acidophilus NCFM. The counts of L. acidophilus in the samples on days 1, 15, and 30 of the storage were determined. Additionally, the samples contained L. acidophilus were passed through a dynamic gastrointestinal model designed in laboratory conditions to compare the protective effect of different dairy products on viability of L. acidophilus against stress factors of the gastrointestinal model. The counts of L. acidophilus NCFM and L. acidophilus DSM 20,079 in the samples decreased by between 0.04 and 0.37 log units and by between 0.11 and 0.27 log units, respectively, within 30 days of storage. During the passage through the gastrointestinal model, the highest percentage reduction in the counts of L. acidophilus was determined in yoghurt followed by fermented acidophilus milk, white pickled cheese, and ice cream, respectively. The reduction in the counts of L. acidophilus in the samples during the passage through the model increased with extension of storage time. The results of this study showed that the reduction in the counts L. acidophilus in the samples during the passage through the model was influenced significantly by the matrix of the dairy product and storage period.

Colouring properties and stability of black carrot anthocyanins in yoghurt

Among the natural pigments anthocyanins have potential to be applied as natural colourants besides exhibiting wide range of bioactivity. Colouring potential and storage stability of black carrot concentrate (BCC) containing anthocyanins in yoghurt was determined in present investigation. The instrumental colour (CIELAB) values were altered by the addition of BCC in yoghurt in which the L* and b* values decreased, while a* value increased with increasing levels of BCC. Maximum sensory scores were observed for yoghurt with 1.5% BCC, as it was similar to strawberry in colour and appearance. Enhancement in the total anthocyanin, total phenolics and DPPH antioxidant activity was observed with increasing levels of BCC in yoghurt. L* value remained same during storage in both yoghurts, but a* value increased slightly. Similar trend was also noticed in BCC yoghurt for anthocyanins and antioxidant activity. The total phenolic content got enhanced in control, but decreased significantly in BCC yoghurt. Sensory evaluation revealed that scores decreased during storage but the product was acceptable up to 15 days. Our study further confirmed that higher stability and better colouring properties of black carrot concentrate in fermented milk system was due to higher degree of acylation.

Development of yoghurt powder using microwave-assisted foam-mat drying

Yoghurt powder is widely used in industries of confectionery and baking. The production of yoghurt powder can be made by several drying methods, including freeze, spray, microwave vacuum, convective and foam-mat. In this study, the effect of varying concentrations of egg albumin (EA) on foam and powder characteristics of yoghurt were determined. Besides, microwave-assisted foam-mat drying of yoghurt was carried out to examine the effects of three microwave output powers (100, 180 and 300 W) on powder properties of yoghurt. Increased in EA concentration resulted in an increase in foam expansion and decrease in foam density. Higher foam stability (after 120 min.) was observed for foams containing 10 and 15% EA (both found as 88.24%). As powder properties, wettability and solubility times were significantly decreased with the addition of EA, while water holding capacity was increased. Change in EA concentration was significantly (p ≤ 0.05) effective on all powder properties dried at 100 W. Carr Index and Hausner Ratio values were in the range of 0.99-13.89 and 1.01-1.17, respectively. Microwave powers were significantly (p ≤ 0.05) effective on the flowability of powders containing 0, 5 and 10% EA. Yoghurt powders showed mostly excellent flow characteristics (for all concentrations of EA and microwave output powers).

Bacterial exopolysaccharides for improvement of technological, functional and rheological properties of yoghurt

Exopolysaccharides (EPS) are known to have technological and functional applications in food industry including dairy based products such as yoghurt. Yoghurt is a widely consumed dairy based product due to pleasant taste and texture, as well as a source of nutrients and bioactive compounds. At the same time, structural, rheological and sensorial properties are important in the production of good quality yoghurt. Various natural hydrocolloids including EPS with stabilizing and texture enhancing properties could be useful in enhancing these desirable properties. Apart from that, EPS may enhance various other functional properties of yoghurt such as antioxidant and prebiotic potential. Based on its prebiotic property, symbiotic products could be developed by combining EPS and probiotic bacterial strains. EPS has potential to provide physical and micro structural stability, thereby enhancing the protein distribution and viscoelastic properties. Main focus of the present review is to provide an insight on the action of EPS as a functional hydrocolloid on the technological, rheological and functional properties of yoghurt and related products.

Antioxidant activity and some quality characteristics of buffalo yoghurt fortified with peanut skin extract powder

Peanut is an important crop grown worldwide. Peanut skin, the byproduct of peanut processing is a valuable byproduct due to its content of many functional components. Therefore, this study aimed to evaluate the effect of fortification of yoghurt with peanut skin extract powder (PSEP) at 50, 100 and 200 mg/L milk on the antioxidant activity (radical scavenging activity RSA%) and some quality characteristics of the resultant yoghurt during cold storage. The obtained results revealed that total phenolic content of PSEP is 109.46 mg GAE/g while it's radical scavenging activity % reached 90.57%. Fortification of yoghurt with PSEP increased the apparent viscosity, antioxidant activity, and total phenolic, acetaldehyde, and diacetyl contents as compared to control, while the syneresis of fortified yoghurt was reduced. Microbiological analysis showed that fresh control yoghurt had the highest counts of Streptococcus thermophilus and Lactobacillus bulgaricus and decreased at the end of storage in all treatments. Both control and T1 (the low concentration of PSEP) gained the highest acceptability; therefore, it was recommended that fortification of yoghurt with 50 mg of PSEP/L is more preferable than the other concentrations. In addition, it could be considered as a natural antioxidant source in formulating functional yoghurt either in industrial and/or small industrial scale.

Use of kefir and buttermilk to produce an innovative quark cheese

Quark cheese is a fermented soft fresh cheese categorised under acid-rennet coagulated cheeses. In this study, alternative raw materials such as kefir and yayik buttermilk were used to produce Quark cheese in comparison with the cheese produced by the acidification of skim milk with mesophilic lactic culture. Samples were kept individually under 35 °C and 100 °C for coagulum formation. Obtained cheeses, were evaluated in terms of some physicochemical, microbiological and sensorial properties in addition to the volatile and peptide profiles. Quark produced from kefir and buttermilk was determined to have preferred properties directly affect the cheese characteristics.

Characteristics of fish gelatin-anionic polysaccharide complexes and their applications in yoghurt: Rheology and tribology

In this study, the rheological and tribological properties of complex solutions comprising of fish gelatin (FG)-Arabic gum (AG), FG-xanthan gum (XG), and FG-κ-carrageenan (κC), respectively, were measured, as well as the effects of the complex on the physical properties of yoghurt. Results showed that with increased XG and κC concentrations, the viscosity of FG-XG and FG-κC complex solutions both increased. It was also found that the lubrication properties of FG-anionic polysaccharide (AP) solutions decreased with the increased AP contents. The applications of FG-AP complexes (FG:AP = 9:1) improved firmness, water holding capacity and viscosity of yoghurt by the formation of large aggregates, but gels were easily destroyed at high frequency. Moreover, compared with gelatin, FG-AP complexes made yoghurt better lubrication properties during low and medium sliding speed, especially for FG-XG complexes. Thus, FG-AP complexes have the potential to be applied in producing yoghurt with good quality.

Consumption of yoghurt favours remission after faecal microbiota transplantation for chronic pouchitis

PURPOSE

The gut microbiota is conceivably a key factor in the aetiology of pouchitis. Faecal microbiota transplantation (FMT) has been suggested as a promising new treatment for chronic pouchitis, where treatment options often are few. However, little is known about the influence of the diet on the clinical effects of FMT. We assessed the diet of patients with chronic pouchitis undergoing FMT to investigate the influence of diet on the clinical outcome after FMT.

METHODS

Nine patients with chronic pouchitis were allocated to treatment with FMT delivered by enema from five faecal donors for 14 consecutive days in a 6-month prospective, open-label, single-centre cohort pilot study. A dietary questionnaire was completed at baseline for all patients and donors. Patients underwent a pouchoscopy at baseline and at 30-day follow-up, and the Pouchitis Disease Activity Index (PDAI) was assessed.

RESULTS

Patients' diets were generally similar, when comparing patients in remission post-FMT (PDAI < 7) with those who relapsed (PDAI ≥ 7). Consumption of grains trended to be different between the two groups (p = 0.06), where patients in relapse consumed more bread products than did patients in remission. However, consumption of yoghurt was significantly different between the two groups (p = 0.04), with patients in remission consuming more yoghurt (mean 1.1 s/d vs 0.2 s/d).

CONCLUSION

Gastroenterologist performing clinical studies on FMT for chronic pouchitis should be aware of dietary habits as contributing factors for the clinical effect of FMT.

Yoghurt and curd cheese addition to wheat bread dough: Impact on in vitro starch digestibility and estimated glycemic index

The effect of yoghurt and curd cheese additions on pasting properties, starch digestibility and estimated glycemic index of wheat bread were studied. Yoghurt and curd cheese incorporations (6% up to 25% w/w) promoted considerable changes on starch performance based on gelatinization and final dough consistency properties. These changes led to a significant impact on starch digestibility, reducing significantly the rapidly digestible starch while increasing the resistant starch. The estimated glycemic index reflected the changes promoted on starch performance from both dairy products addition, at higher level tested (25%): a significant reduction of around 30% for yoghurt bread and 38% for curd cheese bread, was obtained, resulting in medium to low (55-69) glycemic index breads. Correlations were found between pasting properties, starch digestibility and glycemic index, revealing that the effects observed are proportional to the levels of dairy products added. Microstructure images of the starch granules supported these findings.

Microbial composition of sweetness-enhanced yoghurt during fermentation and storage

The reformulation of dairy products to contain less added sugar can contribute to reducing sugar consumption, thereby reducing the risk of non-communicable diseases. The objective of this study was to investigate the microbial ecology of reformulated yoghurt, which was produced using bi-enzymatic modification of lactose to increase its sweetness by a factor of 2–3. Ultimately, this reformulation strategy could reduce the amount of added sugar needed for equal sweetness of the end product. The bi-enzymatic modification relied on utilisation of a β-galactosidase enzyme to convert the milk sugar lactose to galactose and glucose, followed by the enzymatic conversion of the glucose moiety to fructose using a glucose isomerase. The microbial ecology of reformulated yoghurt produced with two mixed starter culture preparations containing either Streptococcus (S.) thermophilus and Lactobacillus (Lb.) delbrueckii or S. thermophilus, Lb. acidophilus and Bifidobacterium sp. strains, was analysed during fermentation and cool storage using 16S rRNA based metagenomics. None of the yoghurt samples showed a significant difference in microbial composition between sweetness-enhanced and regular milk at all sampling time points during manufacture and storage of yoghurt. However, a significant difference between the microbiota of inoculated milk before and after fermentation was observed. In both types of yoghurt, the starter culture genera dominated the microbial ecology at the end of fermentation as expected, reducing the possibility of growth of potentially pathogenic or spoilage bacteria possibly resulting from a changed carbohydrate spectrum.

Yoghurt fermentation alters the composition and antiplatelet properties of milk polar lipids

Dairy polar lipids (PL) seem to exhibit antiplatelet effects. However, it is not known what molecular species may be responsible. In this study, we confirmed using C30 reversed-phase (C30RP) ultra-high-performance liquid chromatography (UHPLC) coupled to high resolution accurate mass tandem mass spectrometry (HRAM-MS/MS) that fermentation of yoghurts from ovine milk using specific starter cultures altered the PL composition. These lipid alterations occurred concomitant with increased antithrombotic properties of the yoghurts PL fractions against platelet-activating factor (PAF) and thrombin-induced platelet aggregation. Specifically, elevation in phosphatidylethanolamine (PE), sphingomyelin (SM), phosphatidylcholine (PC) and their molecular species were observed following yoghurt fermentation. Furthermore, PC(18:0/18:1), PE(18:1/18:2), SM(d18:0/22:0) and several other molecular species were significantly inversely correlated with the inhibition of PAF and thrombin. These molecular species were abundant in the most bioactive yoghurts fermented by S. thermophilus and L. acidophilus, which suggest that fermentation by these microorganisms increases the antithrombotic properties of ovine milk PL.

HAV detection from milk-based products containing soft fruits: Comparison between four different extraction methods

Virus detection in food requires appropriate elution and concentration techniques which need to be adapted for different food matrices. ISO/TS-15216-1:2017 and ISO/TS-15216-2:2019 describe standard methods for hepatitis A virus (HAV) research in some food only. Milk-based products containing one or more types of fruit are not covered by ISO procedures, even though they can be contaminated by fruit added to these products or by the food handlers. The aim of this work was to identify an efficient method for the detection of HAV in milk-based products. Four methods were tested to recover HAV from artificially contaminated milk, yoghurt and ice cream containing soft fruits. Results showed that the efficiency of the tested methods depends on the analyzed matrix. In milk we obtained a mean recovery from 13.4% to 1.9%; method based on high speed centrifuge gave the best values. The average recovery in yoghurt was between 3.3% and 114.4%, the latter value achieved by method with beef extract at 3% as eluent. Finally, two methods gave the best results in ice cream with similar recoveries: 29.1% and 27.7% respectively. The first method used glycine as eluent while the other one was based on high speed centrifugation. The ISO method has never proved to be the most efficient in the matrices studied. Therefore, based on the results obtained, a complete rethinking of the ISO method may be necessary to improve its recovery for some products such as milk, while only small changes would be sufficient for other products, such as yoghurt and ice cream.

Dairy product consumption and hypertension risk in a prospective French cohort of women

BACKGROUND

Among potentially modifiable factors, dairy product consumption has been inconsistently associated with hypertension risk. The objective of this study was to investigate the relation between dairy product consumption and the risk of hypertension among middle-aged women.

METHODS

In a prospective cohort of 40,526 French women, there were 9340 new cases of hypertension after an average 12.2 years of follow up. Consumptions of milk, yogurt, and types of cheese were assessed at baseline using a validated dietary questionnaire. Hazard ratios (HRs) and 95% confidence intervals (95% CI) for hypertension were estimated with multivariate Cox models with age as the time scale.

RESULTS

The mean dairy consumption was 2.2 + 1.2 servings/day, as cottage cheese (0.2 + 0.2 servings/day), yogurt (0.6 + 0.5 servings/day), milk (0.4 + 0.7 servings/day), and cheese (1.1 + 0.8 servings/day). There was no association between risk of hypertension and total dairy consumption (multivariate HR for the fifth vs. first quintile HR_5vs.1 = 0.97 [0.91; 1.04]). There was no association with any specific type of dairy, except for a positive association between processed cheese consumption and hypertension (multivariate HR_{4vs.1 =} 1.12 [1.06; 1.18]; p trend = < 0.003).

CONCLUSIONS

In this large prospective cohort of French women, overall consumption of dairy products was not associated with the risk of hypertension. Results regarding processed cheese must be further confirmed.

Hypothesis: Bacterial induced inflammation disrupts the orderly progression of the stem cell hierarchy and has a role in the pathogenesis of breast cancer

BACKGROUND

The hierarchical model of stem cell genesis is based on the idea that the number of cell divisions between the zygote and fully differentiated epithelial cells is kept close to the minimum, which is log to the base 2 of the total number of cells produced in a human lifetime. The model assumes the orderly progression of stem cell divisions requires precise control at every stage in development. If the orderly progression is maintained then cancer will be rare. A prediction of the model is that if the orderly progression of the stem cell hierarchy is disturbed by trauma, ulceration or inflammation then cancer will occur.

HYPOTHESIS

Bacterial induced inflammation in breast ducts disturbs the stem cell hierarchy and is a cause of breast cancer.

EVIDENCE

Mammalian milk is not sterile. It contains a range of bacteria, derived endogenously by the entero-mammary circulation. The dominant flora consists of lactose fermenting bacteria. Pregnancy and breast feeding reduce the risk of subsequent breast cancer. The implication is that a lactose fermenting bacterial flora in breast ducts is protective. Malignant and benign breast tissue contains bacteria derived endogenously, but studies so far have not revealed a specific flora associated with malignancy. Periodontitis is associated with oral, oesophageal, colonic, pancreatic, prostatic and breast cancer. The pathogenic bacteria which cause periodontitis spread endogenously to cause inflammation at other epithelial sites. Meta-analysis of epidemiological studies shows that the consumption of yoghurt is associated with a reduction in the risk of breast cancer.

CONCLUSION

The hypothesis, although not proven, is supported by the available evidence. Lactose fermenting bacteria protect but pathogenic bacteria which induce inflammation raise the risk of breast cancer. The consumption of yoghurt also appears to be protective.

Immature wheat grain as a potential prebiotic ingredient in set-type yoghurts: impact on antioxidative, textural properties and survival of different probiotics

The aim of this study was to investigate the effect of immature wheat grain (IWG) on the survival of Lactobacillus acidophilus NCFM (LNCFM), Lactobacillus casei 431 (L431) and Lactobacillus acidophilus 20079 (L20079) in yoghurts under cold storage. Furthermore, the impact of IWG on physicochemical, textural and antioxidative properties of yoghurts was evaluated. Fortification of yoghurt with IWG positively affected LNCFM and L20079 counts during cold storage whereas no statistical improvement was observed in the viability of L431. The addition of IWG clearly supported the antioxidative activity and total phenolic content in yoghurt. No statistical differences were discovered regarding syneresis and water holding capacity in all probiotic applications. Although, enrichment with IWG enhanced the firmness of probiotic yoghurts, it simultaneously reduced the cohesiveness and viscosity index. This study demonstrated that IWG may be used as a food additive for enhancing probiotic LNCFM and L20079 survival and providing functional aspects in yoghurt.

Rapid determination of majority cations in yoghurts using on-line connection of capillary electrophoresis with mini-dialysis

An analyser was constructed on the basis of on-line connection of capillary electrophoresis over a short separation path with continuous mini-dialysis sample collection. The developed instrument was employed for simultaneous determination of the majority minerals K⁺, Ca²⁺, Na⁺ and Mg²⁺ (and possibly NH₄⁺ ions) in commercially available unflavoured yoghurts. The cations are released from the organic structures by digestion with boiling 6 mol/L HCl. They were separated from residues of the organic matrix by a dialysis probe and were transferred to a stream of water. From the continuous stream, the dialysate was injected into the separation capillary through a flow-gating interface. Within the reliability interval, the determined total mineral content was equal to their contents stated on the yoghurt labels and the content determined by flame atomic absorption spectrometry and complexometric titration. The relative standard deviation of the electrophoretic determination is mostly about 5%.

Sensory, rheological and chemical characteristics during storage of set type full fat yoghurt fortified with barley β-glucan

β-Glucan, is a soluble dietary fiber and is obtained from number of sources including cereals. It possesses the nutraceutical characteristics and acts as functional bioactive ingredient in the fermented dairy product including yoghurt. In this concern, β-glucan isolated from barley having purity of (91.52%) was incorporated in different proportions (0.5, 1, 1.5 and 2%, w/v) during the full fat yoghurt preparation. The analysis of β-glucan carried out initially, indicated that the viscosity, water binding capacity, swelling power and solubility values were 92 Pa s, 3.17 g/g, 18.50 g/g and 3%, respectively, whereas, the total antioxidant activity obtained in terms of DPPH free radical scavenging activity was 27%. Based on these characteristics β-glucan extract had been considered as the choicest material for set type products like yoghurt. Thereafter, physiochemical, rheological and sensory characteristics of β-glucan incorporated yoghurt were evaluated during 1st, 7th and 14th days of refrigerated storage. Addition of β-glucan significantly (p ≤ 0.05) improved whey separation (syneresis), viscosity, texture profile and sensory characteristics during storage. The TPA characteristics such as hardness, cohesiveness and resilience of yoghurt samples improved significantly during storage with the incorporation of β-glucan whereas, β-glucan added yoghurt obtained higher consistency coefficient (K), thus, indicated a thicker and compact texture. Sensory analysis of stored yoghurt indicated that yoghurt samples in the present study containing even higher (1.5-2%) β-glucan level had obtained the higher average overall acceptability (8.1 to 8.3 on 9-point scale) score as compared to a low fat yoghurt containing lower β-glucan level (0.5%) reported in the literature.

Low concentrations of Lactobacillus rhamnosus GG (Yoba®) are safe in male Drosophila melanogaster

OBJECTIVE

The purpose of the study was to generate information on the safety of probiotics, thus the study objectives were to evaluate the effects of Yoba® on basic physiochemical properties. The study assessed male w1118 Drosophila melanogaster which were provided food supplemented with Yoba® at 1%, 3%, 6%, and 12% on motor function, total protein, catalase activity, and hydrogen peroxide scavenging activity and lifespan.

RESULTS

Yoba® at high concentration (≥ 6%) increased locomotor activity in Drosophila melanogaster, however, total protein, catalase, and hydrogen peroxide scavenging activity were significantly higher at 1% Yoba® compared to 3%, 6%, and 12% Yoba®. Yoba consumed at 1% was associated with greater physiological benefits in Drosophila melanogaster. Findings in the study offer a rationale for the consumption of Yoba® at 1% in humans as is currently being promoted by the Yoba for Life consortium, however, high concentrations of Yoba® would disrupt physiological function as shown by this study.

Effect of probiotic yoghurt on plasma glucose in overweight and obese pregnant women: a randomized controlled clinical trial

INTRODUCTION

There is only some evidence about effectiveness of probiotics for preventing gestational hyperglycaemia. This trial examined the effects of probiotic yoghurts containing Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 on maternal plasma glucose (primary outcome) and on some maternal and infant complications (secondary outcomes) in overweight and obese women with no diabetes in pregnancy.

METHODS

Using stratified block randomization, women with pre- or early-pregnancy BMI ≥ 25 and fasting plasma glucose < 92 mg/dl at 22 weeks of gestation were assigned into probiotic or conventional yoghurt group, consuming 100 g/day from 24 weeks of gestation until delivery. The women and their infants were followed up until 1 month after birth.

RESULTS

In each group, one out of 65 women had intra-uterine foetal death and were not analysed for other outcomes. The mean BMI was 29.2 (SD 3.3) in probiotic and 30.3 (SD 4.1) in conventional yoghurt group. Four weeks after initiation of the treatment, plasma glucose levels were significantly lower in the probiotic than in conventional yoghurt group at fasting (mean difference adjusted for the BMI category) and baseline FPG (- 4.0 mg/dl; 95% confidence interval - 6.9, - 1.1) and 2-h OGTT (- 13.9; - 22.8, - 5.0). At the 1-h OGTT, however, the difference was not statistically significant (- 9.8; - 20.6, 0.9). Further, there was a significantly lower infant bilirubin level in the probiotic group on days 3-5 after birth (- 2.2 mg/dl; - 3.3, - 1.2). There were not statistically significant differences between the groups regarding the risk of gestational diabetes (6 vs 11; odds ratio 0.5; 0.2, 1.5), preterm delivery (3 vs 8; 0.3; 0.1, 1.2), and other maternal and infant outcomes.

CONCLUSION

The probiotics supplementation has some beneficial effects on glucose metabolism of overweight and obese pregnant women. Nevertheless, further studies are required to judge the clinical significance of such effects.

Identification of cow, buffalo, goat and ewe milk species in fermented dairy products using synchronous fluorescence spectroscopy

In the dairy industry, substitution of high priced milk species with low priced ones is a common practice, and determination of milk species is critical. In this study, synchronous fluorescence spectroscopy (SFS) method was developed for identification of milk species in fermented dairy products (yoghurt and cheese). Three partial least square-discriminant analysis models were developed in order to identify pure-mixed samples, milk species and binary mixture type, and partial least square (PLS) model was utilized to quantify the mixing ratio in binary mixtures. PLS models used for yoghurt and cheese samples showed that detection limits of adulteration were below 3.3%. Apart from the buffalo-cow yoghurt and goat-cow cheese, precision of the measurements was found to be below 6.2. It can be said that SFS technique is applicable on yoghurt and cheese samples as it's a less destructive and a less costly method compared to DNA and protein based conventional methods.

Effect of L. acidophilus and B. lactis on blood glucose in women with gestational diabetes mellitus: a randomized placebo-controlled trial

BACKGROUND

Gestational diabetes mellitus (GDM) is a complication of pregnancy that can be associated with neonatal complications and adverse pregnancy outcomes. Recently, probiotic use has been proposed for better control of glucose in GDM patients. The aim of this study was to evaluate the effect of probiotic yoghurt compare with ordinary yoghurt on GDM women.

METHODS

In this double-blind placebo-controlled clinical trial, 84 pregnant women with GDM were randomly assigned into two groups of 42 recipients who underwent 300 g/day of probiotic yoghurt or placebo for 8 weeks. Blood glucose, HbA1c, and the outcome of pregnancy were compared between the two groups after the intervention.

RESULTS

According to the findings of present trial no significant differences were observed in general characteristics between the two groups (p > 0.05). Both fasting and post prandial blood glucose as well as the level of HbA1c were decreased significantly in probiotic group (p < 0.05), although these changes are not statistically significant in the placebo group. The between group differences was significant after the 2 month intervention (p < 0.05). Neonates born of probiotic group mothers, have significantly lower weight and fewer macrosome neonates were born in this group compared with control group (p < 0.05). However, no difference was observed in other values of outcome.

CONCLUSIONS

Our study revealed that better control of blood glucose can be achieved by consumption of probiotic yoghurt in patients whose pregnancy is complicated by GDM, compared with placebo. Also incidence of macrosomia may be decreased by this regimen.

TGF-β activity in cow milk and fermented milk products: An in vitro bioassay with oral fibroblasts

OBJECTIVE

Milk is a rich source of transforming growth factor (TGF)-β which supports intestinal mucosal homeostasis of infants. Milk may also have beneficial effects on the integrity of the oral cavity, its being part of the gastrointestinal tract. However, it is unclear if milk and fermented milk products provoke a TGF-β response in oral cells.

MATERIAL AND METHODS

Human gingival fibroblasts were exposed to pasteurized cow milk, yoghurt, sour milk, buttermilk and whey, followed by a reverse transcriptase polymerase chain reaction of the TGF-β target genes interleukin11 (IL11), proteoglycan4 (PRG4), and NADPH oxidase 4 (NOX4). Immunoassays were performed for IL11 and TGF-β in cell culture supernatant and milk products, respectively. Signaling was investigated with the TGF-β receptor type I kinase inhibitor SB431542.

RESULTS

We report here that pasteurized cow milk and the aqueous fractions of yoghurt, sour milk, buttermilk and whey enhanced the expression of IL11, NOX4 and PRG4 in gingival fibroblasts. Moreover, IL11 protein levels in the respective supernatant were significantly increased. Cow milk, yoghurt, sour milk and buttermilk contain approximately 1-2 ng TGF-β1, whereas active TGF-β1 is hardly detectable in whey. SB431542 reduced the response of gingival fibroblasts to pasteurized cow milk and fermented milk products based on IL11 release into the supernatant.

CONCLUSIONS

These results demonstrate that gingival fibroblasts respond to pasteurized cow milk and to fermented milk products with an increased expression of TGF-β target genes.

Modeling of rheological characteristics of the fermented dairy products obtained by novel and traditional starter cultures

Tree different fermented dairy products obtained by conventional and non-conventional starter cultures were investigated in this paper. Textural and rheological characteristics as well as chemical composition during 21 days of storage were analysed and subsequent data processing was performed by principal component analysis. The analysis of samples` flow behaviour was focused on their time dependent properties. Parameters of Power law model described flow behaviour of samples depended on used starter culture and days of storage. The Power law model was applied successfully to describe the flow of the fermented milk, which had characteristics of shear thinning and non-Newtonian fluid behaviour.

Natural food colourants derived from onion wastes: application in a yoghurt product

The valorization of onion (Allium cepa) solid wastes, a 450,000 tonnes/year waste in Europe, by a green extraction method is presented. Polyphenols of onion solid wastes were extracted using eco-friendly solvents, such as water and glycerol. The 2-hydroxypropyl-β-cyclodextrin was also used as a co-solvent for the augmentation of the extraction yield. The process has been optimized by implementing a central composite face centered design of experiments, with two replicates in the central point, taking into consideration the following independent variables: glycerol concentration, cyclodextrin concentration and temperature. The assessment of the extraction model was based on two responses: the total pigment yield and the antiradical capacity. LC-MS analysis was also employed in order to identify polyphenols and colourants of the obtained extracts. The main polyphenols found were quercetin and quercetin derivatives and the main colourant was cyanidin 3-O-glucoside. The extract was also tested as a food colourant in a yoghurt matrix. The onion leaf extract was found to be a stable natural colourant and could be utilized as an alternative ingredient to synthetic coloring agents. This article is protected by copyright. All rights reserved.

Determination of nutritional parameters of yoghurts by FT Raman spectroscopy

FT-Raman quantitative analysis of nutritional parameters of yoghurts was performed with the help of partial least squares models. The relative standard errors of prediction for fat, lactose and protein determination in the quantified commercial samples equalled to 3.9, 3.2 and 3.6%, respectively. Models based on attenuated total reflectance spectra of the liquid yoghurt samples and of dried yoghurt films collected with the single reflection diamond accessory showed relative standard errors of prediction values of 1.6-5.0% and 2.7-5.2%, respectively, for the analysed components. Despite a relatively low signal-to-noise ratio in the obtained spectra, Raman spectroscopy, combined with chemometrics, constitutes a fast and powerful tool for macronutrients quantification in yoghurts. Errors received for attenuated total reflectance method were found to be relatively higher than those for Raman spectroscopy due to inhomogeneity of the analysed samples.

Effect of culture levels, ultrafiltered retentate addition, total solid levels and heat treatments on quality improvement of buffalo milk plain set yoghurt

Studied the effect of culture (2, 2.5 and 3%), ultrafiltered (UF) retentate addition (0, 11, 18%), total milk solids (13, 13.50, 14%) and heat treatments (80 and 85 °C/30 min) on the change in pH and titratable acidity (TA), sensory scores and rheological parameters of yoghurt. With 3% culture levels, the required TA (0.90% LA) was achieved in minimum 6 h incubation. With an increase in UF retentate addition, there was observed a highly significant decrease in overall acceptability, body and texture and colour and appearance scores, but there was highly significant increase in rheological parameters of yoghurt samples. Yoghurt made from even 13.75% total solids containing nil UF retentate was observed to be sufficiently firm by the sensory panel. Most of the sensory attributes of yoghurt made with 13.50% total solids were significantly better than yoghurt prepared with either 13 or 14% total solids. Standardised milk heated to 85 °C/30 min resulted in significantly better overall acceptability in yoghurt. Overall acceptability of optimised yoghurt was significantly better than a branded market sample. UF retentate addition adversely affected yoghurt quality, whereas optimization of culture levels, totals milk solids and others process parameters noticeably improved the quality of plain set yoghurt with a shelf life of 15 days at 4 °C.

Optimise the microbial flora with milk and yoghurt to prevent disease

Pathogenic bacteria, which are temporary or permanent members of our microbial flora, cause or contribute to a wide range of human disease at all ages. Conditions include Alzheimer's disease, atherosclerosis, diabetes mellitus, obesity, cancer, autoimmunity and psychosis, amongst others. The mechanism of damage is inflammation which can be chronic or acute. An optimal microbial flora includes a wide range of pathogenic bacteria in low dose. This allows specific immunity to be developed and maintained with minimal inflammatory damage. Human milk has evolved to deliver an optimal microbial flora to the infant. Cow's milk has the potential, following appropriate fortification, to maintain an optimal human microbial flora throughout life. Yoghurt is a fermented milk product in which bacteria normally present in milk convert sugars to lactic acid. The acid suppresses the growth of pathogens in the oral cavity, oropharynx and oesophagus. Thus yoghurt can restore an optimal flora in these regions in the short term. Since bacteria are transported between epithelial surfaces, yoghurt will also optimise the flora elsewhere. The judicious use of milk and yogurt could prevent a high proportion of human disease.

Optimization of low-fat set-type yoghurt: effect of altered whey protein to casein ratio, fat content and microbial transglutaminase on rheological and sensorial properties

In the present study the amount of whey protein to casein ratio (W/C ratio) (0.22-0.7), fat content (FC) (0.5-1.5%) and microbial transglutaminase (mTGase) (0.0-1.0 U/g substrate protein) in the formulation of low fat set type yoghurt, prepared from reconstituted milk, were optimized by response surface method to achieve the best rheological properties and sensory characteristics. The selected parameters consisted of higher consistency coefficient, consistency, texture and mouth feeling and lower syneresis and pH. The optimum condition was found to be 0.97, 0.46 and 0.5% of the enzyme concentration, W/C ratio and FC respectively. Results showed that thermal denaturation increased up to 33% with increasing W/C ratio significantly. All samples showed non-Newtonian shear thinning behavior. Increasing in W/C ratio from 0.22 to 0.7 raised the consistency coefficient, yield stress and textural parameters such as hardness and consistency of yoghurt. Enzyme addition (together with starter culture addition) increased yoghurt viscosity and yield stress. In sensory evaluation W/C ratio affected the texture and mouth feeling of yoghurt samples and the influences of FC and mTGase were not significant. Yoghurt syneresis was highly affected by FC, W/C ratio and mTGase.

Experimental effect of ozone upon the microbial flora of commercially produced dairy fermented products

Ozone was used to control spoilage microorganisms during the manufacturing of dairy products. Ozone stream was applied onto the surface of freshly filled yoghurt cups just before storage for curd development in order to prevent cross contamination from spoilage airborne microorganisms. Accordingly, brine solution was bubbled with ozone for various periods of time and used for ripening of white (feta type) cheese. Both products were subjected to a continuous monitoring of microbial load and also tested for their sensorial properties. In ozonated yoghurt samples there was a reduction in mould counts of approximately 0.6Logcfu/g (25.1%) by the end of the monitoring period in relation to the control samples. In white cheese ripened with ozonated brine (1.3mg/L O₃, NaCl 5%) it seems that ozone treatment during the two months of observation reduced some of the mould load but without offering any advantages over the use of traditional brine (NaCl 7%). However, some sensorial alterations were observed, probably due to the organic load in the brine which deactivates ozone in early stages of application. It is concluded that, if the factors of time and concentration of ozone are configured properly, ozonation could be a promising approach safeguarding the production of some dairy products.

Sweetening yoghurt with glucose, but not with saccharin, promotes weight gain and increased fat pad mass in rats

The claim that non-nutritive sweeteners accelerate body weight gain by disrupting sweet-calorie associations was tested in two experiments using rats. The experiments were modelled on a key study from a series of experiments reporting greater body weight gain in rats fed yoghurt sweetened with saccharin than with glucose (Swithers & Davidson, 2008). Both of the current experiments likewise compared groups fed saccharin- or glucose-sweetened yoghurt in addition to chow and water, while Experiment 1 included a third group (Control) given unsweetened yoghurt. In Experiment 1, but not in Experiment 2, rats were initially exposed to both saccharin- and glucose-sweetened yoghurts to assess their relative palatability. We also tested whether the provision of an energy-dense sweet biscuit would augment any effects of saccharin on food intake and weight gain, as seemingly predicted by Swithers and Davidson (2008). In Experiment 1 there were no differences in body weight gain or fat pad mass between the Saccharin and Control group, whereas the Glucose group was the heaviest by the final 5 weeks and at cull had the largest fat pads. Greater acceptance of saccharin predicted more weight gain over the whole experiment. Consistent with past reports, fasting blood glucose and insulin measures did not differ between the Saccharin and Control groups, but suggested some impairment of insulin sensitivity in the Glucose group. Experiment 2 found similar effects of glucose on fat mass, but not on body weight gain. In summary, adding saccharin had no detectable effects on body-weight regulation, whereas the effects of glucose on fat pad mass were consistent with previous studies reporting more harmful effects of sugars compared to non-nutritive sweeteners.

Longitudinal association of dairy consumption with the changes in blood pressure and the risk of incident hypertension: the Framingham Heart Study

We aimed to examine the longitudinal association of dairy consumption with the changes in blood pressure (BP) and the risk of incident hypertension (HTN) among adults. This study included 2636 Framingham Heart Study Offspring Cohort members who participated in the 5th through 8th examinations (1991-2008) and were free of HTN at their first examination during the follow-up. Data collected at each examination included dietary intake (by a validated FFQ), BP (following standardised procedures) and anti-hypertensive medication use (by physician-elicited self-report). HTN was defined as systolic BP (SBP)≥140 mmHg, or diastolic BP (DBP)≥90 mmHg or anti-hypertensive medication use. We used repeated-measure and discrete-time hazard regressions to examine the associations of dairy consumption with the annualised BP change (n 2075) and incident HTN (n 2340; cases=1026), respectively. Covariates included demographic, lifestyle, overall diet quality, metabolic factors and medication use. Greater intakes of total dairy foods, total low-fat/fat-free dairy foods, low-fat/skimmed milk and yoghurt were associated with smaller annualised increments in SBP and a lower risk of projected HTN incidence. However, with the exception of total dairy foods and yoghurt, these inverse associations with HTN risk were attenuated as the follow-up time increased. For yoghurt, each additional serving was associated with 6 (95 % CI 1, 10) % reduced risk of incident HTN. Total dairy and total low-fat/fat-free dairy intakes were found to be inversely related to changes in DBP. Dairy consumption, as part of a nutritious and energy-balanced diet pattern, may benefit BP control and prevent or delay the onset of HTN.

Effects of yeast, carboxymethylcellulose, yoghurt, transglutaminase and cyclodextrinase on mixing properties of oat dough

The effects of yeast, carboxylmethylcellulose (CMC), plain yoghurt (YG), transglutaminase (TG) and cyclodextrinase (CG) on the mixing properties of oat dough were investigated through the use of DoughLab. A 2(5-2)fractional factorial design resolution III with yeast (1.25, 3.25 %), CMC (1, 2 %), YG (10.75, 33.75 %), TG (0.5, 1.5 %) and CG (10, 40 μl) as independent variables was implemented. The parameters measured were water absorption, arrival time, stability, energy at peak, peak resistance, development time, departure time, softening and bandwith at peak. CMC significantly (p < 0.05) increased stability, energy at peak, development and departure times, but significantly (p < 0.05) decreased water absorption, peak resistance, softening and bandwidth at peak. TG signficantly increased water absorption, peak resistance and softening, but significantly decreased energy and development time. YG significantly (p < 0.05) decreased all the parameters measured, with the exception of softening, which was significantly increased. In contrast, yeast and cyclodextrinase did not significantly affect the oat dough during mixing. Principal component analysis indicated that 85.5 % of the variation in the data could be explained by two components. Component 1 explaining 52.3 % of the variation loaded highly on dough strength (stability and departure time). Component 2 contributing 33.2 % of the variation loaded on dough resistance (water absorption and peak resistance). CMC significantly increased dough strength while yoghurt reduced it significantly. TG significantly (p < 0.05) increased the resistance of the dough to mixing while CMC and yoghurt reduced it significantly (p < 0.05). Hence, CMC, TG and yoghurt are ingredients of choice when modifying oat dough mixing properties.

Physico-chemical, sensory and microbiological characteristics of plain yoghurt from bambara groundnut (Vigna subterranea) and soybeans (Glycine max)

Physico-chemical, sensory and microbiological characteristics of plain yoghurt from bambara groundnut and soybean milks were studied. Milks were prepared from bambara and soybean and then fermented using Lactobacillus delbruieckii subspp. bulgaricus and Streptococcus salivarus subspp. thermophilus to produce yoghurt. The yoghurts were stored at 7 °C and 27 °C for 9 days and their quality monitored. Results showed that pH of soy and bambara yoghurts decreased during the storage period for both storage temperatures. This decrease in pH was accompanied by simultaneous increase in titratable acidity. Total solids and apparent viscosities of soy and bambara yoghurts increased at 7 °C, but decreased at 27 °C during storage period. Bambara yoghurt received higher sensory acceptability than soy yoghurt. Predominant microorganisms in the stored yoghurts were lactic acid bacteria (LAB). The LAB count in the yoghurts stored at 7 °C decreased but increased at 27 °C during the storage period. Similar trends were followed by total aerobic bacteria, yeast and moulds counts. Pathogenic bacteria such as Salmonella, Coliform and E. coli were absent in all the yogurt samples. Yoghurts of acceptable quality and safety were produced from bambara groundnut and soybeans.

Antibiotic overuse and Clostridium difficile infections: the Indian paradox and the possible role of dietary practices

Antibiotic abuse is rampant in India, such that one may expect to see an increase of Clostridium difficile infections (CDI). However, we found that the incidence of CDI in India (1.67%) is no different from that reported in USA (1.6%) using similar techniques of detection (polymerase chain reaction test). We offer a possible explanation for this paradox. It is likely that a diet rich in fiber, yogurt, and possibly turmeric may have a protective role in decreasing the incidence of CDIs in India.

The effect of yoghurt and its probiotics on blood pressure and serum lipid profile; a randomised controlled trial

BACKGROUND AND AIMS

Despite strong mechanistic data, and promising results from in vitro and animal studies, the ability of probiotic bacteria to improve blood pressure and serum lipid concentrations in humans remains uncertain. The aim of this study was to determine the effect of Lactobacillus acidophilus La5 and Bifidobacterium animalis subsp lactis Bb12, provided in either yoghurt or capsule form, on home blood pressure and serum lipid profile.

METHODS AND RESULTS

Following a 3-week washout period, 156 overweight men and women over 55 y were randomized to a 6-week double-blinded, factorial, parallel study. The four intervention groups were: A) probiotic yoghurt plus probiotic capsules; B) probiotic yoghurt plus placebo capsules; C) control milk plus probiotic capsules; and D) control milk plus placebo capsules. Each probiotic test article provided a minimum L. acidophilus La5 and B. animalis subsp. lactis Bb12 dose of 3.0 × 10⁹ CFU/d. Home blood pressure monitoring, consisting of 7-day bi-daily repeat measurements, were collected at baseline and week 6. Fasting total cholesterol, low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), and serum triglyceride were performed at baseline and week 6. When compared to control milk, probiotic yoghurt did not significantly alter blood pressure, heart rate or serum lipid concentrations (P > 0.05). Similarly, when compared to placebo capsules, supplementation with probiotic capsules did not alter blood pressure or concentrations of total cholesterol LDLC, HDLC, or triglycerides (P > 0.05).

CONCLUSIONS

The probiotic strains L. acidophilus La5 and B. animalis subsp. lactis Bb12 did not improve cardiovascular risk factors.

bulgaricus and Streptococcus thermophilus in traditional yoghurt enriched by honey and whey protein concentrate

The ability of whey protein concentrate (WPC) (1% w/v) and/or honey (2% and 4% w⁄v) to improve lactic acid bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) growth and viability in yoghurt during a 21 day period of storage was investigated. Another focus of this study was to examine fermentation kinetics and post-acidification rates through pH and lactic acid content measurements over the 21 day period. The addition of WPC and acacia honey accelerated fermentation and improved lactic acid bacteria (LAB) growth over the 21 days, but honey proportion did not significantly affect the viability of LAB. Moreover, adding honey and WPC did not support the overproduction of lactic acid, which positively influenced yoghurt stability during the 21 day storage period.