ELECTRONIC JOURNAL OF FOOD PROCESSING AND PRESERVATION
Year:2013 | Volume:5 | Issue:2|Papers Count:8

In this study, ice-glazing process of frozen shrimp by chitosan was applied to protect the frozen shrimp from undesirable chemical and physical changes. The effects of 2% chitosan solution glazing on quality of whole, raw and cooked (without head, tail and shell) shrimps stored at -18±2oC for 6 months were investigated and compared with water glazing, sodium metabisulfite treatment control. Glazing yield, thaw yield, freezing loss, drip loss, cooking drip loss, thawing loss, peroxide value and sensory characteristic (color, odor, texture and overall acceptance) of shrimp samples were determined and evaluated at o day and 6 months after frozen storage time. The results of this study showed the effectiveness of the glazing process by 2% chitosan solution as a protecting method for frozen shrimps and this process was more desirable in comparison with water glazing, sodium metabisulfite treatment and control.

Biopolymer based nano-complex is a category of nano-carriers which are produced by interaction between protein and polysaccharide. They can carry hydrophobic nutriciuticals in aqueous solutions and also cause to increase of protection and bioavailability of encapsulated active materials. In this research, gellan-caseinate complexes containing omega3 were produced by adding gellan solutions to caseinate solutions containing omega3 and adjusting pH to below of caseinate isoelectric point (pI=4.9). The results of particle size studies by lazar diffractions showed that particle sizes were continues increased with increasing caseinate concentration from 0.1 to 0.5 and 1% and adding gellan gum to caseinate solutions in two level of 0.05 and 0.1 % caused to decrease in size. The smallest particle (385 nanometer) were produced at the level of 0.1 % of gellan and caseinate and at this concentration, more than 50% and 90% of particles had diameter below 372 nm and 1170 nm, respectively. The turbidity increased with increasing gellan concentration from 0.5 to 0.1 which attributed to decreasing of particle size. The rheometry results showed that the lowest viscosity and highest consistency, shear thinning behavior and viscoelastic behavior could be observed at samples containing 0.1% and 0.05 % gellan, respectively. Gas chromatography results showed which increasing caseinate and gellan caused to decrease and increase in encapsulation percent, respectively and the highest level of encapsulation were observed at complex containing 0.1% gellan and 0.1%caseinate.

Edible films and coatings can improve quality and shelf life of foods (including egg) by reducing the loss of moisture and gases. In the present study, the effects of optimization of carboxymethyl cellulose-based coating on important physical properties of eggs (i.e, weight loss and Haugh units) were investigated. For this purpose, concentration of three ingredients (independent variable) used in formulation of CMC based edible coating (i.e, CMC, oleic acid and glycerol) was studied by using response surface methodology (RSM) on the base of central composite design with 18 treatment and 4 replication of central point. The optimum concentration levels of independent variables for producing the best coating on the base of minimum weight loss and maximum HU (dependent variables) in egg determined to be as follows: Weight loss: 0.45 (%w/v) CMC, 0.01 (%v/v) glycerol and 1.99 (%v/v) oleic acid Haugh unit: 1.01 (%w/v) CMC, 0.1 (%v/v) glycerol and 1.99 (%v/v) oleic acid.

Cheese ripening especial ripening of Ultra-filtered white cheese is, gradual, continuous and so slaw process that not probed completely. In commercial levels have been efforts in order to increase ripening speed and accelerate the formation of ripened cheese flavor and aroma’s especial in Ultra-filtered white cheeses. The addition of exodigenouse activator and accelerator enzymes in this between is one of the usuale tryes. The Ultra-filtered white cheeses was made from cow's milk retentive. Plasminogen activator, urokinase, was added to treatment samples. In order to exactly investigate the effects of plasmin activity on cheese properties, samples contain inhibitor of plasmin activity, 6-Amino hexanoic acid, was prepared. The effects of presence activator and inhibitor in treatment samples on proteolysis and plasmin activity was investigated during 60 days. The addition of activator, urokinas, to retentate significantly (P<0.05) increase plasmin activity whit conversion of plasminogen’s to plasmins and at the result initial proteolysis of cheese was accelerated. Presence of inhibitor and especial urokinase in cheese, could have significant (P<0.05) influences in the amount of pH=4/6 soluble nitrogen and in %12 3-Chloro acetic acid soluble nitrogen. The protein profile's was investigated using urea-Poly acrylamide gel electrophoresis was affected by addition of activator and inhibitor. The results obtained this research, showed that amount of plasmin activity had significant (P<0.05) effects on UF white cheese ripening speed. So increased plasmin activity, could accelerate UF white cheese ripening.

In this study, independent variables were time (1-15 min0, temperature (25-45) and power of ultrasound. Results showed that time of ultrasound was linear (P<0.01) and also effect of interaction time with power (P<0.05) affect on extraction of curcumin significantly. In order to optimization of time, temperature and power of ultrasound response surface central composite deign was used methodology. Results represented that 2F generated adequately explained the data variation and significantly represented the actual relationship between the independent variables and the response. In the optimum point, time, temperature and power of ultrasound levels were found to be 8 min, 35oC and 55 %, respectively.

In this study the effect of Basil seed gum (BSG) concentration (0%, 0.005%, 0.02%, 0.08%, 0.15% and 0.3% w/w) on the stability, particle size distribution and rheological properties of O/W emulsion stabilized by whey protein isolate (0.5% w/w) was investigated at neutral pH. The emulsion prepared by using a sonicator with a nominal power output of 150 W and an operating frequency of 20 kHz. Sonication of samples was carried out in a temperature-controlled chamber at a constant temperature of 20oC for 6minutes. The results of stability showed that after 28 days the highest and the lowest creaming index was related to the emulsion with 0.3% and 0.15% Basil seed gum (w/w), respectively. Rheological data showed that all model emulsions exhibit non-Newtonian shear- thinning flow behaviors (n<1). The best model for emulsions without and with 0.005% Basil seed gum (w/w) was Ostwald and for the another emulsions was Herschel-Balklley. The consistency coefficient k, which is a reflection of the viscosity, has been significantly increased with the increasing gum concentration. The flow behavior index n, which indicates the extend of shea-thining behavior is decreased by the increase in Basil seed gum concentration. The results of frequency sweep experiments showed that at low frequency, all emulsions indicated both viscous(G”) and elastic (G’) behavior but at high frequency all emulsions only indicated a viscous behavior The results of particle size distribution showed that the addition of Basil seed gum up to 0.3% had no significant effect on the particle size. At 0.3% concentration, over presence non adsorbed polysacharid result in depletion fluccolation and significant increase in particle size.

Plants are rich source of phenolic compounds (phenolic acids, flavonoids and tannins) that are most important natural antioxidants. In the present study two ultrasonic methods including probe and bath were used for the extraction of phenolic and flavonoid compounds from Celtis australis. The effects of different extraction time including 30, 60 and 90 min (bath method) and 5, 10 and 20 min (probe method) on extraction of phenolic and flavonoid compounds were evaluated and then the ability of extracts to scavenge DPPH free radical were evaluated using three extraction solvent of water, 80% methanol and 70% ethanol. The results showed that in the probe method of ultrasonic, the highest phenolic compound (8.906±0.017 milligrams gallic acid/ g dry sample), the flavonoid (3.35±0.056 mg of quercetin/g of dry sample) and DPPH radical scavenging activity (94.723±1.127 mg of quercetin/g of dry sample) and DPPH radical scavenging activity (94.74%) were obtained using 70% ethanol within 20 minutes extraction. The minimum extraction of phenolic compounds was obtained using water for 5 minutes with 4.315±0.184 milligrams gallic acid/ g dry sample. In the ultrasound bath, the highest extraction rate of phenolic compounds (8.816±0.015 mg gallic acid equivalent/ g dry sample) was extracted using 70% ethanol for 90 minutes. The ethanol 70-90 minutes with 2.536±0.02 mg of quercetin/g of dry sample showed the highest extraction rate of flavonoid compounds between all treatments. The minimum extraction of phenolic, flavonoid, DPPH radical scavenging activity was obtained using water -30 minutes (for ultrasonic Bath) and water-5 minutes (for ultrasonic probe). Results showed that two methods of ultrasound had different effect on extraction of bioactive compound from Celtis australis. In each extraction method, the extraction rate of phenolic and flavonoid compounds were solvent-dependent.

The lactic acid bacteria in 9 samples of the fermented camel milk, Chal, taken from rural area and retail markets were identified on the basis of their physiological and morphological properties. From the samples, 93 LAB species including, 64 Bacillus (68.8%), 8 cocci 8.6%), 11 Coccobacillus (11.83%), 2 Streptococcus (2.15%) and 8 tetrade (8.6%) were identified. Among the lactobacillus species, Lactobacillus plantarum (13%) and in cocci shapes, different species of Leuconostoc (13%) were the predominant. All the isolates exept, Lactobacillus viridescens, Lactobacillus kefi and Lactobacillus delbrueckii subsp. Bulgaricus were fermented the galactose. Results showed all the isolates, aerobically growth at 37 C and only species identified as Leuconostoc mesenteroides subsp. Cremoris and Leuconostoc paramesenteroides could not grow at 30 C. Only Lactobacillus divergens feremented the Glycerol as carbon source and Lactobacillus fermentum produced the co2 from Sodium gluconate. Between the isolates only Lactobacillus helveticus and Leuconostoc mesenteroides could not grow in the presence of sodim chloride 2%. Many of lactic acid bacteria isolated from chal such as Lactobacillus fermentum, Lactobacillus reuteri, Streptococcus thermophilus, Lactobacillus helveticus, Lactobacillus delbrueckii subsp. Bulgaricus, Lactobacillus plantarum, Lactobacillus hilgardii, Lactobacillus casei subsp. Paracesei, Lactobacillus casei subsp rhamnosus, Lactobacillus curvatus, Lactobacillus brevis, Lactobacillus delbrueckii subsp. Delbrueckii, Lactobacillus acidophilus and Lactobacillus gasseri classified in the probiotic bacteria group. Fortheremore, chal can be consider as a probiotic dairy product.