Spirulina is a microalga that is well-known for its high protein content and biological activities directly related to its antioxidant capacity.The objective of this study was to produce fast-dissolving antioxidant na...Spirulina is a microalga that is well-known for its high protein content and biological activities directly related to its antioxidant capacity.The objective of this study was to produce fast-dissolving antioxidant nanofibers based on Spirulina protein concentrate (SPC) and gelatin using needleless electrospinning technique.The effect of mixing ratios of SPC (10% w/w) and gelatin (20% w/w) on the viscosity,electrical conductivity and surface tension of electrospinning solutions as well as diameter and morphology of resulting nanofibers was investigated.Increasing the SPC level in the solution blends resulted in a decrease in apparent viscosity and electrical conductivity and an almost stable trend in surface tension (29.25–32.19 mN/m) that led to diminish of diameter of the nanofibers.Scanning electron microscopy images showed that SPC/gelatin ratio of 40:60 led to the production of uniform and bead-free nanofibers with a relatively smaller average diameter (208.7 ± 46.5 nm).Atomic force microscopy images indicated mesh-like,fibrillary,and bead-free structures.Fourier transform infrared spectroscopy verified the formation of composite nanofibers and intermolecular interactions between both proteins.X-ray diffraction and thermal analysis showed higher amorphous structure and stability of produced SPC/gelatin nanofibers in comparison to pure materials which was favorable for formation of stable fast-dissolving fibers.Results of DPPH and ABTS radical scavenging activities showed that the antioxidant activity of composite nanofibers significantly improved with increasing SPC mixing ratio (p < 0.05).The dissolution test demonstrated that SPC/gelatin nanofibers can be rapidly dissolved in aqueous medium within 2 s.Finally,the results indicated that the electrospun SPC/gelatin nanofibers could be potentially used for nutraceutical delivery in food and packaging applications under high humidity.展开更多
This study aims to amend nitrite-free fermented sausage texture already produced in our laboratory using microencapsulation of fermenting probiotic bacteria Lactobacillus plantarum PTCC1896 and Lactobacillus fermentum...This study aims to amend nitrite-free fermented sausage texture already produced in our laboratory using microencapsulation of fermenting probiotic bacteria Lactobacillus plantarum PTCC1896 and Lactobacillus fermentum PTCC1744 (CNF treatment) and taking place physical, chemical, and microbial analyzes in comparison with cooked fermented sausages containing 120 ppm nitrite and aforementioned microencapsulated bacteria (CN treatment) and uncooked fermented sausages containing 120 ppm sodium nitrite and free bacteria (N treatment). Different percentages of sodium alginate, inulin and maltodextrin were used to evaluate the viability of bacteria. Combination of sodium alginate 1%, inulin 3% and maltodextrin 3% (w/v each) for L. plantarum PTCC1896 and sodium alginate 1%, inulin 5%, and maltodextrin 10% (w/v each) for L. fermentum PTCC1744 showed the most protective effects. The results of colorimetry showed that the mentioned bacteria could produce the desired red color of the sausage. The moisture content of cooked samples was significantly different from N treatment (p < 0.05). The pH of all treatments was within the desired range of microbial stability. The texture and microbial evaluation results showed that cooked treatments have better texture properties and lower microbial load during storage (p < 0.05). Considering the effects of cooking on the texture of sausage, the appropriate survival of microencapsulated bacteria and comparing the analyzes of the three treatments, the absence of nitrite and replacing it with the mentioned bacteria had no adverse effects and brought desirable results. Therefore, it is possible to produce nitrite-free probiotic fermented sausage with suitable organoleptic properties by cooking fermented sausage.展开更多
文摘Spirulina is a microalga that is well-known for its high protein content and biological activities directly related to its antioxidant capacity.The objective of this study was to produce fast-dissolving antioxidant nanofibers based on Spirulina protein concentrate (SPC) and gelatin using needleless electrospinning technique.The effect of mixing ratios of SPC (10% w/w) and gelatin (20% w/w) on the viscosity,electrical conductivity and surface tension of electrospinning solutions as well as diameter and morphology of resulting nanofibers was investigated.Increasing the SPC level in the solution blends resulted in a decrease in apparent viscosity and electrical conductivity and an almost stable trend in surface tension (29.25–32.19 mN/m) that led to diminish of diameter of the nanofibers.Scanning electron microscopy images showed that SPC/gelatin ratio of 40:60 led to the production of uniform and bead-free nanofibers with a relatively smaller average diameter (208.7 ± 46.5 nm).Atomic force microscopy images indicated mesh-like,fibrillary,and bead-free structures.Fourier transform infrared spectroscopy verified the formation of composite nanofibers and intermolecular interactions between both proteins.X-ray diffraction and thermal analysis showed higher amorphous structure and stability of produced SPC/gelatin nanofibers in comparison to pure materials which was favorable for formation of stable fast-dissolving fibers.Results of DPPH and ABTS radical scavenging activities showed that the antioxidant activity of composite nanofibers significantly improved with increasing SPC mixing ratio (p < 0.05).The dissolution test demonstrated that SPC/gelatin nanofibers can be rapidly dissolved in aqueous medium within 2 s.Finally,the results indicated that the electrospun SPC/gelatin nanofibers could be potentially used for nutraceutical delivery in food and packaging applications under high humidity.
文摘This study aims to amend nitrite-free fermented sausage texture already produced in our laboratory using microencapsulation of fermenting probiotic bacteria Lactobacillus plantarum PTCC1896 and Lactobacillus fermentum PTCC1744 (CNF treatment) and taking place physical, chemical, and microbial analyzes in comparison with cooked fermented sausages containing 120 ppm nitrite and aforementioned microencapsulated bacteria (CN treatment) and uncooked fermented sausages containing 120 ppm sodium nitrite and free bacteria (N treatment). Different percentages of sodium alginate, inulin and maltodextrin were used to evaluate the viability of bacteria. Combination of sodium alginate 1%, inulin 3% and maltodextrin 3% (w/v each) for L. plantarum PTCC1896 and sodium alginate 1%, inulin 5%, and maltodextrin 10% (w/v each) for L. fermentum PTCC1744 showed the most protective effects. The results of colorimetry showed that the mentioned bacteria could produce the desired red color of the sausage. The moisture content of cooked samples was significantly different from N treatment (p < 0.05). The pH of all treatments was within the desired range of microbial stability. The texture and microbial evaluation results showed that cooked treatments have better texture properties and lower microbial load during storage (p < 0.05). Considering the effects of cooking on the texture of sausage, the appropriate survival of microencapsulated bacteria and comparing the analyzes of the three treatments, the absence of nitrite and replacing it with the mentioned bacteria had no adverse effects and brought desirable results. Therefore, it is possible to produce nitrite-free probiotic fermented sausage with suitable organoleptic properties by cooking fermented sausage.
