Effect of Storage on Syneresis, pH, Lactobacillus acidophilus Count, Bifidobacterium bifidum Count of Aloe vera Fortified Probiotic Yoghurt

Psychobiotic interventions attenuate chronic alcohol use-mediated exacerbation of posttraumatic stress disorder in rats: the role of gut-liver axis response

OBJECTIVES

The incidence of co-occurring alcohol-use disorder (AUD) and post-traumatic stress disorder (PTSD) is high, and the presence of one disorder aggravates the severity of the other. Emerging evidence shows the neuroprotective and anti-inflammation functions of psychobiotics. Hence, the study explored the effects of probiotics and synbiotic inulin on the gut- and liver-oxidative and inflammatory biomarkers in chronic alcohol exacerbation of PTSD symptoms in rats.

METHODS

Young adult rats were administered 10% ethanol in a two-bottle choice test for six weeks and were subjected to single prolonged stress. Probiotics and synbiotic intervention followed this. Markers of oxido-inflammatory stress, liver functions, intestinal (faecal) metabolites, occludin expression, and histopathology of the ileum and liver were evaluated.

RESULTS

Chronic alcohol drinking and PTSD increased oxido-inflammatory stress, markers of hepatic damage, and reduced faecal metabolites, which were attenuated by probiotic and synbiotic interventions. Furthermore, reduced immunoexpression of gut and liver occludin, with loss of barrier integrity, viable hepatocytes, congestive portal area, and shortened villi and crypt depth, were observed. Probiotic and synbiotic interventions mitigated these effects.

CONCLUSIONS

The study demonstrates that psychobiotics mitigate the detrimental effects of co-occurring chronic alcohol intake in the context of PTSD.

Effect of Collagen Types, Bacterial Strains and Storage Duration on the Quality of Probiotic Fermented Sheep’s Milk

Collagen has become popular in dietary supplements, beverages and sports nutrition products. Therefore, the aim of this study was to evaluate the possibility of using various doses of collagen and collagen hydrolysate to produce probiotic sheep’s milk fermented with Lactobacillus acidophilus, Lacticaseibacillus casei, Lacticaseibacillus paracasei and Lacticaseibacillus rhamnosus. The effects of storage time, type and dose of collagen, and different probiotic bacteria on the physicochemical, organoleptic and microbiological properties of fermented sheep’s milk at 1 and 21 days of refrigerated storage were investigated. The addition of collagen to sheep’s milk increased the pH value after fermentation and reduced the lactic acid contents of fermented milk compared to control samples. After fermentation, the number of probiotic bacteria cells was higher than 8 log cfu g⁻¹. In sheep’s milk fermented by L. acidophilus and L. casei, good survival of bacteria during storage was observed, and there was no effect of collagen dose on the growth and survival of both strains. The addition of collagen, both in the form of hydrolysate and bovine collagen, resulted in darkening of the color of the milk and increased the sweet taste intensity of the fermented sheep’s milk. However, the addition of hydrolysate was effective in reducing syneresis in each milk sample compared to its control counterpart.

Encapsulation of Different Types of Probiotic Bacteria within Conventional/Multilayer Emulsion and Its Effect on the Properties of Probiotic Yogurt

Microencapsulation of probiotic cells within emulsion is an efficient method to enhance the viability of probiotic bacteria. In the present study, free and encapsulated probiotic cells (Lactobacillus rhamnosus and Lactobacillus plantarum) in simple and multilayer emulsions were used to produce a set of probiotic yogurts. In all samples, an increasing trend in syneresis and acidity values and a decreasing trend in pH and viability of probiotic cells were observed during the storage time. However, the changes in these parameters were more significant for free-loaded probiotic samples. Moreover, the free cells showed poor survival in the yogurt samples by decreasing the viable cell count of probiotics from 7.71–7.59 logs CFU/mL to 6.93–6.82 log CFU/mL during storage, while encapsulation in the multilayer emulsion showed an insignificant reduction from 7.65–7.59 logs CFU/mL to 7.55–7.45 log CFU/mL at the end of storage. The obtained results showed that the type of probiotic bacteria had no significant effects on the physicochemical and structural properties of samples. However, encapsulating probiotics in multilayer emulsion led to a more homogenous structure in yogurt. The sensorial properties were also not affected by the probiotic type and the encapsulation method. Consequently, the multilayer emulsion can provide an ideal delivery carrier for encapsulating probiotic bacteria in dairy products.

The Effect of Essential Oils on the Survival of Bifidobacterium in In Vitro Conditions and in Fermented Cream

Essential oils derived from plant materials are a mixture of compounds that exhibit antibacterial properties. Due to their distinct aroma, they also serve as a desirable natural additive for various food products, including dairy products. In this study, the essential oils of lemon peels, clove buds, and juniper berries were obtained by steam distillation and characterized using gas chromatography–mass spectrometry to determine their chemical compositions and effects on the viability of seven Bifidobacterium strains. Furthermore, the effect of essential oils on the viability of Bifidobacterium animalis subsp. lactis Bb-12 was investigated in cream samples during fermentation and after storage for 21 days at 6 °C. The fatty acid composition of fat extracted from essential oils containing sour cream samples and the volatile aroma compound profile of the sour cream samples were also determined chromatographically. Among the 120 compounds identified, monoterpene hydrocarbons were dominant in the essential oils of lemon peels (limonene and γ-terpinene) and juniper berries (sabinene and β-myrcene), while eugenol and eugenol acetate were abundant in the essential oil of clove buds. In addition to these compounds, butanoic and acetic acids were found in the tested sour cream samples. In turn, fat extracted from these samples was rich in saturated fatty acids, mainly palmitic acid. Among the tested strains of the genus Bifidobacterium, B. animalis subsp. lactis Bb-12 was the most sensitive to the essential oils of clove and juniper, as indicated by the larger growth inhibition zones. However, both the concentration and type of essential oils used had no effect on the number of cells of this strain present in the cream samples immediately after fermentation and after its 21-day storage, which suggests that the tested essential oils could be a natural additive to dairy products.

Development of camel and cow's milk, low-fat frozen yoghurt incorporated with Qodume Shahri (Lepidium perfoliatum) and cress seeds (Lepidium sativum) gum: Flow behavior, textural, and sensory attributes' assessment

In this study, the effect of different concentrations (0.2%, 0.1%, and 0%) of some plant seed gums (Qodume Shahri (Lepidium perfoliatum) and cress (Lepidium sativum)) as the stabilizer on the flow behavior, textural, and sensory properties of frozen yoghurt produced from camel and cow's milk was investigated. The results showed that plant seed gums significantly affected the viscosity, overrun and melting rate, textural, and sensory properties of frozen yoghurt samples prepared from camel and cow's milk. Also, no significant differences were observed in pH and acidity of the samples. The highest overrun value was observed in the control sample. Frozen yoghurt containing 0.2% Qodume Shahri seed gum (QSSG) had the highest viscosity and the longest first dripping time. This is an indication that frozen yoghurt mixes are non-Newtonian at all added concentrations. Finally, Herschel-Bulkley model well described the rheological behavior of frozen yoghurt mixtures due to the higher correlation coefficient. In general, cow's frozen yoghurts containing 0.2% cress seed gum (CSG) and 0.1% QSSG were more acceptable among panelists than camel frozen yoghurt sample.

Probiotic Fermented Milk with Collagen

The aim of this study was to assess the possibility of using collagen protein hydrolysate in the production of milk fermented by Bifidobacterium animalis ssp. lactis Bb-12 and Lactobacillusrhamnosus. Physicochemical and organoleptic properties were studied and microbiological analysis of fermented milk was performed on days 1 and 21 of storage. Milk with the addition of 3% collagen protein hydrolysate was pasteurized (85 °C/30 min), divided into two groups, cooled to 37 °C and inoculated: the first group with Bifidobacteriumanimalis ssp. lactis Bb-12, second with Lactobacillus rhamnosus. Incubation was carried out at 37 °C/10 h. After 21 days of refrigerated storage, the pH value decreased in all analyzed milk samples. Collagen protein hydrolysate was a good milk additive to increase gel hardness and reduce syneresis. Moreover, its addition did not change the taste and odour of milk fermented with the use of Bifidobacterium Bb-12 and Lactobacillus rhamnosus. Collagen protein hydrolysate favourably stimulated the survival of Bifidobacterium Bb-12 during 21 days of storage. After 21 days of cold storage in milk with collagen, the number of Lactobacillus rhamnosus cells was reduced by 0.11 log cfu g−1.

Biological reduction of aflatoxin B1 in yogurt by probiotic strains of Lactobacillus acidophilus and Lactobacillus rhamnosus

The present study was conducted to investigate the ability of two probiotic strains, L. acidophilus PTCC 1643 and L. rhamnosus PTCC 1637, to bind aflatoxin B1 (AFB1, 20 ng/ml) in comparison with yogurt starter cultures, at equal bacterial count (~ 109 LogCFU/ml) during a 21-day storage period at 4 °C. All assessed treatments exhibited high percentages of AFB1-binding, ranged from 64.56 to 96.58%. However, the ability of probiotic bacteria was statistically higher than yogurt starter cultures. Aflatoxin binding ability of the selected lactic acid bacteria was dependent on both time and bacteria species. The highest and the lowest percentages of AFB1-removal was observed at 11th day of cold storage by L. rhamnosus (96.58 ± 3.97%) and at the first day of storage for yogurt starter cultures (64.56 ± 5.32%), respectively. The stability of bacterial cells-AFB1 complex was remarkable, since only 0.84-26.75% of bounded AFB1 was released from bacterial cells after 3 times washing during the storage period.

Physicochemical and Microbiological Properties of Synbiotic Yogurt Made with Probiotic Yeast Saccharomyces boulardii in Combination with Inulin

Saccharomyces boulardii is a unique species of yeast previously characterized as a probiotic strain (CNCM I-745) among a few probiotic yeasts reported to date. Inulin is one of the most common prebiotics that exhibit twisted hydrocolloidal properties in dairy products. The present study was designed to develop a synbiotic yogurt by incorporation of S. boulardii and inulin at 1%, 1.5%, and 2% (w/v), comparing with the probiotic and control plain yogurts. Microrheological, microstructural, microbiological, sensory properties, and volatile compounds of the yogurt samples were evaluated. Microrheological analysis showed that addition of inulin to yogurt slightly reduced the values of G' and G″, while solid-liquid balance (SLB) values confirmed more solid properties of the synbiotic yogurt (0.582~0.595) than the plain yogurt (0.503~0.518). A total of 18 volatile compounds were identified in the synbiotic yogurt, while only five and six compounds were identified in plain and probiotic yogurts, respectively. Physiochemical parameters such as pH, acidity, and protein content were in the normal range (as with the control), while fat content in the synbiotic yogurt decreased significantly. Addition of 1% inulin not only reduced syneresis but also maintained viability of S. boulardii after 28 days of storage. Microstructural and microrheological studies confirmed the dense, compressed, homogeneous structure of the synbiotic yogurt. Thus, addition of inulin improved the textural and sensory properties of the synbiotic yogurt, as well as survival of S. boulardii with viable count above 6.0 log CFU/g in yogurt, as generally required for probiotics. Therefore, novel synbiotic yogurt with desirable quality was developed as an effective carrier for delivery of the probiotic yeast exerting its beneficial health effects.

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.

Numerical optimization of probiotic Ayran production based on whey containing transglutaminase and Aloe vera gel

The purpose of this study was to optimize the functional properties of probiotic Ayran. Two-level fractional factorial design with four center points was used to investigate the effect of five independent variables including, reconstructed whey protein (70-90% of milk), salt (0.5-1 g/100 g), Aloe vera gel (0-30 g/100 g), transglutaminase enzyme (0-14 unit/100 g) and storage time (1-21 days). The viability of Lactobacillus acidophilus La-5 and other physicochemical properties such as pH, acidity, viscosity, sedimentation, and color were modeled and then optimized using desirability function method. Results showed that reconstructed whey protein and Aloe vera gel significantly affected the viability of L. acidophilus La-5 and other physicochemical properties (p < 0.05). The viability of L. acidophilus La-5 and viscosity decreased by increasing of whey protein percentage from 70 to 90. Maximum L. acidophilus La-5 count was observed in samples with a minimum level of whey protein and maximum level of Aloe vera gel. Milk replacement with whey protein up to 90% caused to decrease acidity and viscosity significantly but sedimentation increased (p < 0.05). Optimum condition for production of functional Ayran determined as follow: Aloe vera gel concentration: 25.7%, reconstructed whey protein: 70%, salt: 0.58% and transglutaminase enzyme: 5 unit/100 mL.

Matrix-wise evaluation of in vivo and in vitro efficiencies of L. rhamnosus GG-fortified beverages

The interactions between phenolic compounds and gut microbiota, have gained much attention due to their beneficial effect on humans. The study was also conceived keeping in view the growing popularity of probiotics and emerging interest in designing plant based matrices for probiotic delivery. The synergistic relationship between probiotic, Lactobacillus rhamnosus GG (LR) (ATCC 53103) and phenolic compounds of fruit matrices, sea buckthorn (SBT) and apple juice (APJ) was evaluated on TNBS induced enterocolitis in a zebrafish model (Danio rerio). Addition of LR to SBT matrix conferred higher protection against inflammation than LR in APJ matrix. This could be due to higher content of phenolic compounds in SBT. Isorhamnetin was identified as the predominant phenolic in SBT. The juice matrices were also evaluated for their flow and viscoelastic properties. The consistency index (K) and flow behaviour index (η) were derived from evaluating the shear strength. All the tested juice matrices demonstrated shear-thinning properties. Effect of the matrices on other functionalities of LR during storage period of 14 days was also evaluated. No significant changes were observed on cell surface hydrophobicity depicting protective action of the matrix components on the probiotic strain. Gastrointestinal tolerance increased on Day 7 and 14. Principal Component Analysis of the anti-microbial potential of the probiotic beverage formulations against pathogenic and food spoilage strains showed higher antagonistic ability of LR in SBT during the 14 days storage. The key findings suggest probiotic strain may behave differently in different food matrices. The sustainable functionality of the probiotic strain can be achieved even during the shelf period by optimum design of the delivery matrix.

Phytochemicals and syneresis of osmo-dried mulberry incorporated yoghurt

The research was aimed to study the effect of the addition of Osmo-air-dried mulberry (TSS 29.33%) in yoghurt on syneresis and a bioactive component of yoghurt. Two types of yoghurts, with or without Osmo-dried mulberry, were developed using standard culture (Streptococcus thermophilus and Lactobacillus bulgaricus), and changes at refrigerated temperature (<5°C) were studied. Fruit yoghurt showed high total soluble solids (TSSs) and low-fat content (dry basis) (17.67% and 11.84%) compared with normal yoghurt (9.5% and 17.21%). The addition of fruits increased the ascorbic acid (0.77 to 5.96 mg/100 g yoghurt), anthocyanins content (0 to 7.9 mg/100 g yoghurt), total phenol content (TPC) (6.63 to 68.03 mg GAE/100 g yoghurt), and antioxidant activity (20.73% to 47.6% radical scavenging activity) in yoghurt. During 18 days of storage at refrigerated condition (<5°C), the acidity of all samples increased, while pH decreased. Syneresis increased with a storage period in control samples while fruit incorporated yoghurt showed decreased syneresis with time. The viability of lactic acid bacteria (LAB) count went on decreasing at similar rates for both with and without the Osmo-dried mulberry incorporated yoghurt. There is an ample opportunity for utilization of Osmo-air-dried mulberry in yoghurt to prevent syneresis during storage with increased bioactive components.

Effect of ultrafiltered milk permeate and non-dairy creamer powder concentration on low phenylalanine yoghurt's physicochemical properties during storage

Phenylketonuria (PKU) is a genetic disorder that has no cure and all patients with this disorder must adhere to a special diet to prevent the onset of symptoms and mental retardation in children. In this study, analog yoghurt with good and acceptable nutrition benefit for PKU patients was produced. Accordingly, ultrafiltered milk permeate was added at two different concentrations of 4 and 5 w/w % and non-dairy creamer at two different concentrations of 1.5 and 2 w/w %. Subsequently, pH, acidity, protein, fat, dry matter, humidity, syneresis and Phe of the yogurts were determined. Protein content, dry matter, pH, acidity and Phe in the analog yogurt with 5 % permeate and 2 % non-dairy creamer were higher than other yoghurt samples, significantly (P < 0.05). During the storage, pH and syneresis of samples reduced, while acidity significantly increased. Phe content of analog yoghurt was low (274 mg/kg).