Food Biotechnology
Saeedeh Fatemizadeh; Mohammad Bagher Habibi Najafi; Dennis Sandris Nielsen
Abstract
IntroductionCronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies have explored the direct interaction between probiotics and C. sakazakii. ...
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IntroductionCronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies have explored the direct interaction between probiotics and C. sakazakii. In this study, the effect of a Lactiplantibacillus plantarum strain (M17) along with the standard strain Lactobacillus plantarum (ATCC 8014) and the well-characterized probiotic strain Lactobacillus rhamnosus GG on the adhesion of C. sakazakii to intestinal epithelial cells was analyzed. Materials and MethodsAcid and bile tolerance of M17 was evaluated in the presence of pepsin and pancreatin. L-arginine hydrolysis was investigated using an arginine-including medium. Auto-aggregation and co-aggregation assays were performed by absorbance measurement. Minimum inhibitory concentrations of the antimicrobials recommended by the European Food Safety Authority were established. Total lactic acid and the ratio of D/L lactate isomers were determined with a Megazyme enzymatic kit. The ability of the isolate to produce biogenic amines was tested by qualitative and quantitative monitoring. Hemolysis was assessed phenotypically on MRS agar enriched with sheep blood. The strain was tested for its capability to adhere to mucin and Caco-2 cells. The antagonistic effects of the strain against C. sakazakii were further evaluated in vitro on mucin and cultured Caco-2 cells. The LAB strain was added simultaneously with, before, and after C. sakazakii to Caco-2 cells for competition, exclusion and displacement assays, respectively. Data analysis was performed in R using one-way analysis of variance, and the experimental groups were compared with the controls using Tukey’s test. P values <0.05 were considered statistically significant. Results and DiscussionThere was no significant difference in the survival rate of M17 and L. plantarum ATCC 8014 at pH = 4. After 2 h of incubation at pH = 2.5, the survival rate of L. plantarum ATCC 8014 was estimated to be higher than strain M17, but this difference was not significant. After 4 hours of incubation at pH = 8, M17 showed a higher survival rate than L. plantarum ATCC 8014, and this difference was significant after transfer from pH = 4. These results confirm the appropriate viability of M17 in the gastrointestinal tract. Both M17 and L. plantarum ATCC 8014 developed the color yellow in the L-arginine hydrolysis assay, which confirms the safety of these strains. The percentage of auto-aggregation for M17, L. plantarum ATCC 8014, and Lactobacillus rhamnosus LGG was estimated at 24.38, 25.28, and 32 after 6 hours, respectively, and no statistically significant difference between the two isolates were noticed. Given the auto-aggregation and co-aggregation parameters of M17, this strain may constitute a defense mechanism against C. sakazakii. Strain M17 showed resistance to kanamycin and clindamycin antibiotics. With intrinsic resistance, the risk of transferring resistance genes is not only speculative, but practically impossible. Intrinsic resistance of lactic acid bacteria may be considered desirable because it ensures their survival when the host is treated with antibiotics. Both D and L isomers of lactic acid were produced by the studied strains. In humans, D(-)-lactic acidosis is a rare metabolic complication that has only been reported in individuals with short bowel syndrome). Clinical studies have shown that the consumption of probiotic bacteria producing D(-)-lactic acid is safe for children and does not cause a long-term increase in blood D(-)-lactic acid. The reference L. plantarum strain and M17 did not produce biogenic amine precursors, and had no ß-hemolytic activity. Mucin adhesion assay exhibited that M17 has less adhesion (12.10 ± 1.14 %) than L. plantarum ATCC 8014 (13.33 ± 2.30 %) and LGG (15.93 ± 2.06 %) although these differences were not statistically significant. However, the amount of adhesion for the positive control sample Escherichia coli K12 (25.19 ± 4.40 %) was significantly higher than those of the other strains. Compared to the positive control, M17 had a significantly lower adhesion rate (6.8 ± 1.41) to CaCo-2 cells. This value was estimated at 13.77 ± 3.53 % for the reference strain and 21.6 ± 7.54 % for Lactobacillus fermentum PCC (positive control). In antagonistic assays, M17 was able to reduce the adhesion of C. sakazakii to mucin and CaCo-2 cells in all three methods of exclusion/inhibition, competition and displacement. Statistical analysis of the results does not show a significant difference between M17 and LGG. Therefore, the performance of M17 is similar to that of the standard probiotic LGG. ConclusionLactic acid bacteria with acceptable ability to adhere to epithelial cells can be suitable for colonization in the intestine. They can act as a barrier to fight pathogens through various competitive mechanisms, such as co-aggregation with pathogens and adhesion. The M17 strain has an acceptable immune profile and probiotic properties because it shows an acceptable antagonistic activity against C. sakazakii invasion. AcknowledgementThis study was supported by Ferdowsi University of Mashhad (Research affairs) [project No.:46718] and the research infrastructure at the University of Copenhagen.
Food Biotechnology
Rezvan Shaddel; Safoura Akbari-Alavijeh
Abstract
[1]Introduction: Today, the incidence of non-communicable and emerging diseases is increasing due to lifestyle changes, reduced mobility and changing dietary patterns. Some clinical evidences in simulated samples and real cases show that some compounds and plant extracts have a significant effect on ...
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[1]Introduction: Today, the incidence of non-communicable and emerging diseases is increasing due to lifestyle changes, reduced mobility and changing dietary patterns. Some clinical evidences in simulated samples and real cases show that some compounds and plant extracts have a significant effect on the prevention and even treatment of these diseases. On the other hand, due to the structural and functional diversity of plant polysaccharides, there is a great tendency among researchers to find new polysaccharides in different sources with new functional and bioactive properties. Despite extensive studies in this field, no study has been done on the extraction of polysaccharide compounds with prebiotic properties from green almond hull as one of the agricultural wastes. Therefore, the purpose of this study was to introduce a new type of synbiotic compound to balance clone microbiota and promote consumer health. Materials and methods: In this study, after extraction of water-soluble almond hull polysaccharides (AHP) by hot water extraction and precipitation with alcohol, the chemical analysis was done. To investigate the chemical composition of AHP, phenol sulfuric acid test was used to measure total sugar and Bradford test was used to measure protein. The amount of fat and ash in the sample was measured using standard methods (AOAC, 2005) and (AOAC, 2000), respectively. The amount of uronic acid of AHP was measured by calorimetry using metahydroxyphenyl at a wavelength of 520 nm. The content of AHP phenolic compounds was investigated by Folin Siocalcu calorimetric method. Fourier transform infrared (FT-IR) was also used to identify the functional groups and the anomeric status of AHP components. The prebiotic effect of this compound was also tested by digestion resistance and also by growth stimulation of the probiotic strain of Lactobacillus casei ATCC 393 in vitro for the first time. Results and discussion: Chemical analysis showed that AHP is a heteropolysaccharide consisting of 86.30% w/w of total sugar, 5.10% w/w protein and 3.21% w/w uronic acid. FT-IR analysis also confirmed the chemical structure of AHP as a heteropolysaccharide. The results of digestion resistance showed that 91.24% of AHP can remain stable and undecomposed after the stages of gastrointestinal digestion, while this rate was 74.94% for inulin as a commercial prebiotic. The second prebiotic property of AHP investigated in this study was the stimulation the growth of Lactobacillus casei ATCC 393 as probiotic in sugar-free MRS-based culture media and the results showed that AHP compared to inulin significantly increased the survival of Lactobacillus casei ATCC 393 (p <0.01). The proliferation index in media containing AHP and inulin showed a significant difference and AHP stimulated the growth of Lactobacillus casei ATCC393 significantly more than inulin (p <0.01). Therefore, to design a synbiotic product, if AHP is used as a prebiotic, the probiotic strain of Lactobacillus casei ATCC 393 would be a good choice.Considering the annual production of thousands of tons of almond green hull waste in Iran and the concerns related to environmental problems caused by its accumulation, the introduction of industrially feasible and economically justified methods to produce value-added products from this agricultural waste seems essential. In the present study, polysaccharides extracted from almond green hull by hot water extraction and alcohol precipitation, which is an economically feasible method and can be implemented on an industrial scale, were introduced as a useful compound. In vitro studies also used culture medium containing AHP as a commercial prebiotic in comparison with culture medium containing inulin. The results showed that this compound has a good resistance to digestive conditions in the gastrointestinal tract compared to inulin. The compound was also able to stimulate the growth of the probiotic Lactobacillus casei ATCC 393 in culture medium. In general, in this study, a new synbiotic compound including Lactobacillus casei ATCC 393 and AHP was introduced as a health beneficial food additive.
Food Biotechnology
Zhila Ghasemi; Mohammad Alizadeh khaled abad; Hadi Almasi; Mehdi Nikoo
Abstract
Nowadays, probiotics have been seriously considered for their potential application in healthy food formulations. The most highlighted concern about probiotics is that the number of probiotic bacteria at the time of consumption may be lower than the required value (107 CFU/g). A new approach is the immobilization ...
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Nowadays, probiotics have been seriously considered for their potential application in healthy food formulations. The most highlighted concern about probiotics is that the number of probiotic bacteria at the time of consumption may be lower than the required value (107 CFU/g). A new approach is the immobilization of probiotic cells in the matrix of edible films. So in this study, edible carboxymethyl cellulose (CMC) probiotic films containing Lactobacillus casei, and the silver carp muscle protein hydrolysates (SCMH) prepared by using limited Alcalase hydrolysis, were analyzed and the viability of bacterial cells was determined at 25, 4, and -18°C for 30 days. An alkaline solubilization/acid precipitation method was used to isolate silver carp white muscle proteins. Protein isolate (3%, W/V) was hydrolyzed with 5% E/S ratio (w/w) Alcalase at 50°C and pH 8.0 for 3 min. Briefly, films were prepared by dissolving SCMH and CMC powder (1.5%, w/v) in a ratio of 1:2 in distilled water and L. casei was added to a final concentration of 108 CFU/mL. Probiotics were counted at intervals of 1, 10, 20, and 30 day. The physical, mechanical [Ultimate tensile strength (UTS) and elongation at break (EB)], thermal and structural properties were determined. XRD patterns of the film samples collected by X-ray diffractometer (XRD) and Fourier transform infrared (FT-IR) spectroscopy of the film samples were recorded. The results indicated that the addition of SCMH significantly (p˂0.05) improved the L. casei viability at all three temperatures. Thickness, moisture absorption, and water vapor permeability (WVP) of the films were not influenced by addition of the probiotic. However, the addition of SCMH negatively affected the film’s mechanical properties. The FT-IR analysis confirmed the formation of hydrogen bonds between L. casei and the CMC matrix, the XRD and differential scanning calorimetry (DSC) analyses confirmed the plasticizing effect of SCMH on the films. Thus, CMC films containing L. casei showed the highest UTS (3.7 MPa) and EB (29.9%). Generally, the results indicated that the SCMH incorporated CMC-based film can be a good carrier for probiotics as bioactive food packaging system with promising potential for shelf life extension of perishable foods.
Food Biotechnology
Elham Rouhi; Alireza Sadeghi; Seyed Mahdi Jafari; Mohammad Abdolhoseini; Elham Assadpour
Abstract
< p >Introduction: Evaluation of probiotic and antifungal properties of lactic acid bacteria (LAB) isolated from fermented substrates has great importance in order to provide microbial cultures for fermentation industries. Among the fermented foods, dairy products play the main role as carriers ...
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< p >Introduction: Evaluation of probiotic and antifungal properties of lactic acid bacteria (LAB) isolated from fermented substrates has great importance in order to provide microbial cultures for fermentation industries. Among the fermented foods, dairy products play the main role as carriers of probiotics. Meanwhile, non-dairy fermented foods have been rarely studied in order to isolation and characterization of their probiotic microorganisms. Sourdough as a mixture of flour and water is a proper fermented ecosystem to isolate probiotic and antifungal LAB. Besides their desired health, probiotics must become active in the consumer''s gastrointestinal tract without any adverse effect. These bacteria can be used as starter, adjunct or preservative cultures to produce different fermented foods. Furthermore, antimicrobial metabolites of the LAB have also numerous potential applications as bio-preservatives in food and/or medical technologies. < p > < p >Materials and methods: In the present study, after continuous back-slopping process, predominant LAB was isolated from fermented quinoa. Then the LAB isolate was identified using PCR amplification of its partial 16S rDNA gene. Subsequently, probiotic properties of the LAB including its resistance to low pH and bile salt, antibacterial effects, aggregation potentials, antibiotic susceptibility and haemolytic activity were investigated. Antifungal effect of the LAB on Aspergillus niger was also determined using overlay bioassay. Finally, the one way analysis of variance (ANOVA) with the least significant difference (LSD) post hock (at p < /em> < p >Results and discussion: Sequencing results of the PCR products led to the identification of Enterococcus hirae as predominant LAB isolated from quinoa sourdough. Sourdough fermentation depends on the several technological and environmental factors and therefore, different types of these complex stressful ecosystems have their specific microflora with unique properties. The LAB isolate had proper survival after continuous pH and bile treatments. Resistance to low pH and bile salt is not sufficient to predict the survival of the probiotics in the actual conditions of the gastrointestinal tract. However, these properties are necessary for assessment of viability and activity in this situation. Furthermore, the highest antibacterial activity of the LAB was observed against Bacillus cereus among the studied food borne indicator bacteria. The effect of crude cell free supernatant (CFS) obtained from LAB isolate on indicator bacteria was significantly (p < /em>
Seyed Mohsen Mortazavi; Hossein Jalali; Seyed Hamidreza Ziaolhagh
Abstract
In this study, the probiotic bacterium Lactobacillus acidophilus with different percentages of pomegranate peel powder (0, 0.5, 1, 1.5, and 2%) were used to produce a functional camel milk-based beverage. The physicochemical, antioxidant and sensory properties of the resulting drinks were evaluated. ...
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In this study, the probiotic bacterium Lactobacillus acidophilus with different percentages of pomegranate peel powder (0, 0.5, 1, 1.5, and 2%) were used to produce a functional camel milk-based beverage. The physicochemical, antioxidant and sensory properties of the resulting drinks were evaluated. The results showed that enrichment of milk with pomegranate peel powder improved the survival of probiotic bacteria from 6.95 to 7.35 Log CFU/ml. Addition of pomegranate peel to beverages increased their antioxidant activity from 7 to 85.33, 9.13 to 93.66 and 0.126 to 0.435 as measured by DPPH free radical scavenging, ABTS+ free radical scavenging and reduction potency tests, respectively. Rheological studies also showed that the addition of pomegranate peel powder to beverages increased their viscosity from 5.65 to 21.5 mPa. Adding pomegranate peel powder to beverages also changed the color factors (L*, a* and b*) so that increasing the level of pomegranate peel powder increased the red and yellow color in the samples. Also, the results of the sensory evaluation, including taste, appearance, smell and general acceptance indicated that the produced beverages were well-liked by consumers. However, the results of sensory evaluation showed that adding high percentages of pomegranate peel powder to beverages could reduce the sensory acceptance of the final product.
Elham Mahdian; Reza Karazhyan
Abstract
A nutraceutical food may provide expanded utility beyond its nutritional benefit. These benefits are commonly attributed to the active components of the food. Fruit by-products are rich source of dietary fibers that have beneficial effects on human health. Also they can improve the growth and viability ...
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A nutraceutical food may provide expanded utility beyond its nutritional benefit. These benefits are commonly attributed to the active components of the food. Fruit by-products are rich source of dietary fibers that have beneficial effects on human health. Also they can improve the growth and viability of probiotics in food matrix and therefore suitable to produce synbiotic food products. In this study, the effect of adding fiber obtained from apple, banana and mango peels at levels of 0.5, 1 and 1.5% on physicochemical and sensory features and the viability of Lactobacillus casei LC-01 in ice cream during 60 days storage at -18°C was investigated. Based on the results, all ice cream mixes were pseudoplastic fluids. The values of flow behavior index decreased and consistency coefficients increased by increasing the level of all mentioned fibers. The pH and specific gravity of samples containing banana and mango fibers were lower than control and sample with apple fiber. Using fibers had no significant effects on overrun values, whereas viscosity and melting resistance of ice cream samples increased with increasing fiber amounts. The most reduction in Lactobacillus casei LC-01 count after freezing and during storage period was associated to control sample and adding all types of examined fibers improved probiotic viability. Minimum cell reduction after freezing and during storage period occurred in sample containing 1.5% mango fiber with 0.03 and 0.48 log cycle respectively. Sensory properties of samples containing apple fiber were good and comparable with control sample.
Ayda Saleh; Mahmoud Rezazadehbari; Mohammad Alizadeh khaled abad; Najmeh Sabahi Mohammadi
Abstract
Introduction : Yoghurt is one of the most popular dairy products in all over the world.Nowadays due to the tendency of consumers to use the products with healthy effects, probiotic and synbiotic products are considered. Yoghurt by itself is a healthy food; because of its high levels of protein and calciumcontents.Consumption ...
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Introduction : Yoghurt is one of the most popular dairy products in all over the world.Nowadays due to the tendency of consumers to use the products with healthy effects, probiotic and synbiotic products are considered. Yoghurt by itself is a healthy food; because of its high levels of protein and calciumcontents.Consumption ofprobiotic bacteria via food products is a way to reestablishthe intestinal microflora balance. Several studies have been done to improve the growth and viability of probiotic bacteria by adding supplements to milk.The objective of this study was to investigate the effect of three component mixture (Arabic gum, whey protein concentrate and milk protein concentrate) on quality indices of synbiotic yoghurt containing transglutaminaseenzyme. The content of theseprotein component, the amount of enzyme, enzyme addition time to the yoghurt samples and storage time were variableMaterials and methods:Yoghurt samples were prepared with milk which contained 2.5 percent fat.Milk was heated around 40 ̊C. WPC, MPC and Arabic gum were added to samples according to the research design and increasing the solid none-fat content of the milk up to 1.5%. Samples were pasteurized at 90 ̊C for 10 minutes in a water bath and were cooled rapidly to 43 ̊C for inoculation starter culture and probiotic bacteria. Also enzyme was added to samples before or after pasteurization (according to the research design).In this study microbial test was done to investigateviability of probiotics (BB-12) by differential culture medium (MRS-LP Agar). The titratable acidity was determined using 0.1 N NaOH until accessing the constant pink colour for 30secondes. Water holding capacity (WHC) was determined due to measure the protein quality of keeping water inside. Syneresis is expressed as the weight percentage of serum released by centrifugation. Viscosity was measured using a Brookfield viscometer.Viscosity measurementswere made using 250 mL ofyoghurt samples at 10 _CDiscussion & Results: The effect of WPC, MPC, Arabic gum, enzyme concentration and theaddition time of enzyme on viability of B. lactis (BB-12) for 21 days of cold storage at 4 ̊C were monitored. The results indicatedthat the effect of Arabic gum, WPC and MPC on viability of probiotic was significant (p
Rahil Rezaei; Morteza Khomeiri; Mehran Alami; Mahdi Kashani-Nejad
Abstract
In this study, effects of Guar and Arabic gum on the viability of two common probiotic, Lactobacillus acidophilus and Bifidobacterium lactis, in frozen yogurt during 60 days were investigated. Results of survival evaluation of probiotics showed that although during storage time bacteria counts decreased ...
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In this study, effects of Guar and Arabic gum on the viability of two common probiotic, Lactobacillus acidophilus and Bifidobacterium lactis, in frozen yogurt during 60 days were investigated. Results of survival evaluation of probiotics showed that although during storage time bacteria counts decreased significantly, this product could maintain 107 cfu/gr of probiotic at the end of storage. Maximum death rate of lactobacillus acidophilus was observed in control sample. Best viability of this microorganism was seen in samples containing 0.2% guar gum and 0.1% Arabic gum that these two treatments had no significant difference. The highest loss of bifidobacterium lactis belonged to sample containing 0.3% guar and lowest was seen in samples containing 0.1% Guar and 0.1% Arabic gum.
Abbas Ahmadi; Seyed Ali Mortazavi; Elnaz Milani; Reza Rezaeemokaram
Abstract
In this study, frozen yoghurt was produced as a synbiotic product. A food product containing both probiotics and prebiotics is named as synbiotic or functional food. Lactobacillus acidophilus (La-5) as a probiotic bacteria was added to frozen yoghurt in two types; free and encapsulated, and its survivability ...
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In this study, frozen yoghurt was produced as a synbiotic product. A food product containing both probiotics and prebiotics is named as synbiotic or functional food. Lactobacillus acidophilus (La-5) as a probiotic bacteria was added to frozen yoghurt in two types; free and encapsulated, and its survivability was evaluated during 60 days storage at -18 °C . Also Fructo-oligosaccharide as a prebiotic compound was used for producing frozen yoghurt in different levels (0%, 0.4% and 0.8% (w/w)). The viable cell number in free state in samples with (0%, 0.4% and 0.8% (w/w)) Fructo-oligosaccharide was 3.8×109 cfu/ml, 3.5×109 cfu/ml and 3.8×109 cfu/ml and after 60 days of storage these numbers were decrease to 2×107 cfu/ml, 2.2×107 cfu/ml and 2.2×107 cfu/ml respectively. Whereas in encapsulated state, the viable cells in samples with (0%, 0.4% and 0.8% (w/w)) Fructo-oligosaccharide these numbers was 7.5×109 cfu/ml, 8.9×109 cfu/ml and 9.8×109 cfu/ml and after 60 days, these numbers were decreased to 2.13×109 cfu/ml, 2.5×109 cfu/ml and 2.9×109 cfu/ml.The results indicated that encapsulation of L. acidophilus could significantly (p
