فهرست مطالب

  • Volume:6 Issue:3, 2019
  • تاریخ انتشار: 1398/04/18
  • تعداد عناوین: 6
|
|
  • Nargess Chatraei, Giti Emtiazi* Pages 139-150
    Background and objective

    Phytase is used in human and poultry additives. This enzyme is mostly produced by Aspergillus niger which is a plant pathogen. Phytase from probiotics is a good candidate for the food supplements.

    Materials and methods

    Bacillus coagulans, as a probiotic, was used for phytase and phosphatase activities on phytin agar and Pikovskayas Agar. The sodium dodecyl sulfatepolyacrylamide gel electrophoresis and zymogram analyses of the extracted phytase enzyme were carried out. Probiotic cells with phytase activity were immobilized on chitosan extracted from shrimp shells and the efficiency was investigated and analyzed using scanning electron microscopy and Fourier transform infrared.Results and

    conclusion

    In this study, Bacillus coagulans showed intracellular phytase activities from broken cells with Soluble Index of 2.5 on phytase specific media. Iron and zinc oxide nanoparticles accelerated the enzyme activity by 25%. Cells were precipitated using ZnO-chitosan nanoparticles and the enzyme activity was investigated on gels. Chelation of chitosan-metal ion increased the positive charge density of chitosan which was expected to enhance adsorption of zinc and teichoic acid on Gram-positive Bacillus coagulans; approved by SEM and FTIR. Cells immobilized on ZnO-chitosan promoted the enzyme activity by 28,800 U ml-1 gel. The entrapped cells were resistance to high temperature and pH. This complex not only included activities against Streptococcus agalactiae, but also dissolved insoluble phosphate and phytin, which has made this complex a good candidate for use as additive in human and animal foods.Conflict of interest: The authors declare no conflict of interest.

    Keywords: Chitosan immobilization, Phytase, Probiotic, Zinc oxide nanoparticles
  • Neda Mollakhalili Meybodi, Amir Mohammad Mortazavian*, Leila Mirmoghtadaie*, Seyede Marzieh Hosseini, Seyyed Ali Yasini, Mohammad Hossein Azizi, Somayeh Mousavi Nodoushan Pages 151-164
    Background and objective

    Lysine-glutamine crosslink formation catalyzed by microbial transglutaminase is supposed to affect improvement of lysine availability in wheat bread. Present study is done to investigate the effect of microbial transglutaminase and fermentation type in improvement of the lysine availability of wheat bread.

    Material and methods

    Lysine-fortified wheat breads were formulated using response surface methodology with composite-face central design. Statistical models were used to predict the impact of defatted soy flour level (0-50% w w-1), microbial transglutaminase level (0-1.6% w w-1) and fermentation type (yeast or mixed fermentation based on sourdough). Further information was provided on the individual role of independent variables in nutritional and structural characteristics of optimized formulation and blank and control samples. Experiments were carried out in triplicate and the mean values were analyzed using one-way analysis of variance and Tukey’s test.Results and

    conclusion

    The suggested formula contained 26.64% w w-1 of defatted soy flour and 0.55% w w-1 of microbial transglutaminase, which was fermented using sourdough-based mixed fermentation and provided 0.16 mg 100 g-1 of available lysine and 2.09 cm3 g-1 of specific volume. The highest lysine chemical score (22.79±0.16), essential amino acid index (35.31±0.37) and biological value (26.79±0.02) and the lowest lysine loss during the baking process seen in optimized formulation verified the effectiveness of microbial transglutaminase in lysine fortification of defatted soy flour/wheat breads (P≤0.05). Considering rheology parameters and textural analysis, microbial transglutaminase treatment increased elastic modulus and β-sheet structure. These structural changes decreased final products digestibility, which can increase using mixed fermentation based on sourdough.Conflict of interest: The authors declare no conflict of interest.

    Keywords: Fermentation, Fortification, Lysine, Transglutaminase, Soy flour, Wheat breads
  • Gallo Marianna*, Nigro Federica, Passannanti Francesca, Salameh Dana, Schiattarella Paola, Budelli Andrea, Nigro Roberto Pages 165-172
    Background and objective

    Consumers show increasing interests in probiotic foods and lactic acid fermentations. Cereal flour, can be a good fermentable substrate due to its prebiotic nature; from which, synbiotic products can be prepared. The aim of the current study was to investigate if three various cereal flours rice, oat and wheat would be good potentially functional foods.

    Material and methods

    Fermentation tests were carried out on rice, oat and wheat flours, using Lactobacillus paracasei CBA L74 and 1.5-L fermenter with 1-L working volume. After 24 h, microbial growth, pH value, lactic acid production and starch consumption were assessed.Results and

    conclusion

    In all three flours, pH reduction was seen; particularly in rice flour. The highest Lactobacillus growth and lactic acid production were achieved at the end of rice fermentation. The greatest starch consumption was reported at the end of rice fermentation. In conclusion, lactic fermentation of cereals as potentially functional foods was possible for the three flours. However, the best result belonged to rice flour.Conflict of interest: The authors declare no conflict of interest.

    Keywords: Cereal flour, Lactic fermentation, Lactobacillus paracasei CBA L74, Probiotics
  • Ramin Radfar, Mehdi Farhoodi, Ismail Ghasemi, Amin Mousavi Khaneghah, Farzaneh Shahraz, Hedayat Hosseini* Pages 173-184
    Background and objective

    Every year, large quantities of date palm seeds are produced as byproducts in date processing and packaging industries, which is discarded or used as low-value materials for animal feeds and composts. However, these bioresources may include potentials to produce high-value added products in food industries. The major aim of the current study was to assess phenolic profiles and contents and antioxidant and antibacterial activities of four Iranian date palm seed extracts, namely Zahedi, Kabkab, Mazafati and Rabbi.

    Material and methods

    Total phenolic contents, phenolic compounds profile and antioxidant and antibacterial activities of extracts from four Iranian date palm seeds were assessed using Folin-Ciocalteu, reversed-phase high-performance liquid chromatography, 2, 2-diphenyl-1picrylhydrazyl radical scavenging, agar disc diffusion and broth microdilution methods, respectively.Results and

    conclusion

    Total phenolic contents varied 1480-3380 mg GAE 100 g-1 dw. cinnamic, chlorogenic, caffeic and 3, 5-dihydroxybenzoic acid included the primary phenolic compounds, respectively. Of the varieties, Kabkab and Mazafati seed extracts with IC50 values of 16.56 and 22.6 µg ml-1 demonstrated the highest and lowest radical scavenging activity, respectively. Results obtained from disc diffusion method revealed that all extracts included inhibitory effects against Staphylococcus aureus, but not against Escherichia coli. Minimum inhibitory concentration and minimum bactericidal concentration of the extracts ranged 1.563.125 and 3.125-12.5 mg ml-1 for Staphylococcus aureus, respectively. Based on the findings, Iranian date seeds are good sources of extractable phenolic compounds with notable antioxidant activities, which can be used as natural additives in formulations of various products such as functional foods and dietary supplements. Furthermore, these seeds can be converted to value added products through biotechnological processes.Conflict of interest: The authors declare no conflict of interest.

    Keywords: Antibacterial properties, Antioxidant activity, Date palm seed, Phenolic profile
  • Zohreh Didar * Pages 185-192
    Background and objective

    Probiotics offer beneficial impact to human health, including lowering serum cholesterol and decreasing occurrence of intestinal infections as well as conferring anti-carcinogenic activities to foods. The present study assessed probiotic doogh drinks made from camel milk and stability of Lactobacillus acidophilus LA-5 (free or microcapsulated) during product shelf life at refrigerated temperatures as well as at simulated gastrointestinal conditions.

    Material and methods

    Microcapsules of Lactobacillus acidophilus LA-5 were produced through coacervation of gelatin and high-methoxy pectin (esterification degree of 70%) or gelatin and Arabic gum as wall materials. Stability of probiotic bacteria in gastrointestinal simulated conditions was assessed. Sensory acceptance of samples was investigated using Hedonic test (9-points) during cold storage for 35 days.Results and

    conclusion

    After 35 days of cold storage, doogh samples included Lactobacillus acidophilus LA-5 microcapsulated by gelatin- pectin and gelatin-Arabic gum had more survival (77.11 and 74.19%, respectively) than free cells (62.34%). As bacteria subjected to simulated gastric juice, the bacterial logarithmic population of free, gelatin-pectin and gelatin-Arabic gum microcapsulated Lactobacillus acidophilus LA-5 reached to 4, 6 and 5, respectively. In the case of exposure to simulated intestinal fluid, logarithm of the bacterial population reached to 5.6, 6.5 and 6.2 for free, gelatin-pectin and gelatin-Arabic gum bacterial microcapsules, respectively. Organoleptic assessment showed no significant differences between samples in terms of aroma, appearance and overall acceptance. As a result, doogh produced from camel milk containing gelatin-pectin and gelatin-Arabic gum microcapsules of Lactobacillus acidophilus LA-5 included a further cold storage stability, compared to that containing free bacteria. Furthermore, a final probiotic population of more than 106 were seen for microcapsules in simulated intestinal fluid.Conflict of interest: The authors declare no conflict of interest.

    Keywords: Camel milk, Doogh, Lactobacillus acidophilus, Microencapsulation, Probiotics
  • Pramuan Saithong*, Supachai Nitipan, Jirawut Permpool Pages 193-200
    Background and objective

    Sap from nipa mangrove palms is rich in nutrition and chemical components. Currently, sap is used for production of fresh juice, syrup, molasses, alcohol and traditional vinegar. The aim of this study was to enhance nutritional values of nipa sap in highquality vinegar using surface culture fermentation.

    Material and methods

    Vinegar was produced from nipa sap using a two-step surface culture fermentation process including vinegar starter culture preparation and vinegar production. Vinegar acetic acid, residual alcohol and pH were optimized. Nipa sap vinegar from surface culture fermentation was compared to that from traditional methods for compliance with regulatory standards. Antioxidant activities (total phenolic content, 2, 2-diphenyl-2picrylhydrazyl radical scavenging and ferric reducing antioxidant power assays) and sensory of the product were assessed.Results and

    conclusion

    Acidity increased to 6.20% using surface culture fermentation at 2.9fold, compared to that using traditional methods (2.14%). Alcohol concentration included 11.9% during wine fermentation. The surface culture fermentation converted alcohol to acetic acid using Acetobacter aceti TISTR 354 in ten days. A good antioxidant activity was reported for the vinegar. Organoleptic properties scored more than “neither like nor dislike” in each attribute. Therefore, high quality vinegars could be produced from nipa sap using surface culture fermentation which could be scaled up in the future.Conflict of interest: The authors declare no conflict of interest.

    Keywords: Acetic acid, Acetobacter sp, Nipa sap, Surface culture fermentation, Vinegar