Abstract This study aimed to examine the production of a synbiotic yogurt sauce and to evaluate its physicochemical, microbiological, sensory, and rheological properties during storage. Lactobacillus paracasei was microencapsulated with resistant starch and sodium alginate by the emulsion technique. Two forms of probiotic bacteria (microencapsulated and free), together with prebiotic compounds (flaxseeds and chia seeds each one at two concentrations of 2% and 4%), were added to the yogurt sauce. Samples were kept for 30 days at 4 ˚C and observed for physicochemical, microbiological, sensory, and rheological characteristics within specific intervals. The results revealed that the produced synbiotic yogurt sauce was characterized as a pseudoplastic fluid. However, its viscosity increased due to the presence of flaxseeds and chia seeds. The addition of flaxseeds and chia seeds improved the survival of bacteria. The post-acidification values were lower in samples containing the microencapsulated bacteria compared to samples containing the free bacteria. Among the produced samples, the highest acceptable score for the sensory characteristic was obtained for the sample containing microencapsulated L. paracasei and 2% flaxseeds. Therefore, it is possible to produce a synbiotic yogurt sauce with desirable properties.

Abstract The present study was aimed to determine the effects of Lactobacillus acidophilus LA-5, L. paracasei 431, and Bifidobacterium lactis BB-12 with lactulose on values of conjugated linoleic acid (CLA) and microbial, physicochemical, and sensory properties of a novel kefir. Thirteen groups were evaluated on days 1, 7, and 14 at 4 oC. The interaction between probiotics and lactulose reduced pH to 4.5 in the first week and slightly decreased on day 14 (4.35). The syneresis value was decreased by increasing the lactulose dose. The interaction could not remarkably increase probiotic survival; the greatest and lowest values were 7.18 and 7.81 log CFU/mL, respectively. The greatest and the lowest lactic acid value was 2.77 and 1.47 g/100 mL, respectively, in kefirs supplemented with L. acidophilus LA-5 and L. acidophilus LA-5+ L. paracasei 431+ B. lactis BB-12. A 4-fold increase in the acetic acid value (0.592 g/100 mL) was observed in kefirs supplemented with B. lactis BB-12 along with L. acidophilus LA-5 and L. paracasei 431 (G12). It is concluded that adding 5% lactulose along with L. acidophilus LA-5+ L. paracasei 431 to kefir could valuably increase the CLA value (3.51-8.07 ppm) and give it more acceptability of flavor, odor, and syneresis.

Abstract Immobilization process is used to facilitate the enzyme recovery and reusability. The aims of this study were to evaluate the effect of different amounts of chitosan on immobilization efficiency of Glucose Oxidase (GOX), pH effect on enzyme activity and changes of kinetic characteristics of enzyme immobilized on Magnetic Chitosan Nanoparticles (MCNP). GOX was immobilized on MCNP with cross bonds and Schiff base covalent connections. The sample with 0.3 g of chitosan had the highest immobilization efficiency (41.30%). Morphology of nanoparticles was investigated by Scanning Electron Microscopy (SEM). Immobilization of GOX on magnetic nanoparticles was verified with Fourier Transform Infrared (FTIR). The effect of pH on enzyme activity was similar on both immobilized enzyme (IE) and free enzyme (FE). The evaluation of kinetic parameters for IE and FE has showed that the effectiveness factor was 0.45. Generally, it could be concluded that magnetic nanoparticles with 0.3 g chitosan could provide a suitable medium for immobilization of GOX.

Abstract Fish oil has many health effects, but due to its strong odor and rapid spoilage, its use in food formulations is limited. For these reasons, nanoencapsulation of fish oil can be important. The purpose of this study was to investigate the influence of whey protein concentrate (WPC) and gum arabic as wall materials on the characteristics of nanoencapsulated fish oil powder. Gum arabic and WPC were used in varying amounts for nanoencapsulation of fish oil. An oil-in-water emulsion with 6% fish oil and 20% aqueous solution of wall materials was prepared by sonication (24 kHz for 120 sec). The diameter of the emulsion droplets was measured by particle size analysis and they then were dried in a freeze-drier. The results showed that the type and concentration of wall material influenced the characteristics of the nanocapsules. The smallest emulsion droplet diameter (50 nm) and the highest encapsulation efficiency were found in the sample containing 100% gum arabic; however, the lowest amount of surface oil, pH and highest zeta potential and moisture content also were recorded for this sample. It can be concluded that gum arabic is more suitable for nanoencapsulation and could appropriately contain the volatile compounds within the capsules.

Abstract The aim of this study was to produce sugar-free whipping cream with desirable quality. Rebaudioside A and isomalt were used as a sucrose substitute and maltodextrin to adjust the taste and texture of the whipping cream. Samples containing different amounts of rebaudioside A, isomalt and maltodextrin (50% Rebaudioside A+50%Isomalt, 50% Rebaudioside A +50%Maltodextrin, 50% Rebaudioside A +25%Isomalt+25% Maltodextrin, 60% Rebaudioside A +40%Isomalt, 60% Rebaudioside A +40% Maltodextrin, 60% Rebaudioside A +20%Isomalt+20% Maltodextrin) were stored for two months. During storage, the syneresis of the samples decreased, but the viscosity increased significantly (p ≤ 0.05). The lowest syneresis value was recorded for the sample containing 60% rebaudioside A + 20% isomalt + 20% maltodextrin and this sample had the best texture. The sample containing 60% rebaudioside A + 40% isomalt scored highest for flavor and overall acceptance. The sample containing 60% rebaudioside A + 40% isomalt and the one containing 60% rebaudioside A +20% isomalt + 20% maltodextrin had the best sensory and physical qualities, respectively. Therefore, rebaudioside A, isomalt and maltodextrin can be used as a sucrose substitute to sweeten and provide suitable texture to whipping cream.