IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2012 | Volume:8 | Issue:33|Papers Count:14

This study was done to investigate effect of extract of Zararia multiflora Boiss on shelf-life of light salted, vacuum packaged rainbow trout (Oncorhynchus mykiss) fillet in refrigerator condition, based on microbial, chemical and sensory attribute assessments. For this purpose, the fillet of this fish were storage in refrigerator during 20 days in three treatments: salted vacuum packaged (V) (as a control), salted in a brine containing 0.5% extract of Z. multiflora (w/w) and then were vacuum packaged (A1) and salted in a brine containing 1% (w/w) extract of Z. multiflora and then were vacuum packaged (A2) and change of free faty acid (FFA), tiobarbitoric acid index (TBA), total volatile nitrogenic basic (TVB-N), total microbial viable count (TVC) and sensory assessments were studied. During storage period, A1 and A2 treatments had lower value of FFA, TVB-N and TBA (p<0.05) and also TVC (p<0.01) than V treatments. According the chemical, microbial and sensory index, in this study, extract of Zararia multiflora increased the shelf-life of rainbow trout fillet about 5-6 days. PCA results showed, the TVC and TVB-N indices were the best indices for quality assessment of rainbow trout fillet in storage conditions of present study. With regarded to the results of the present study, extract of Z. multiflora, as a natural preservative, in combine with salting and vacuum packaging method, is able to increase shelf-life time of rainbow trout fillet in refrigerator conditions and it can be replace with artificial preservatives.

To evaluate antioxidant activity of some natural phenolics, tallow olein was employed as a lipid system. Since animal fats are weak in natural antioxidants, studying antioxidant activity will provide a desirable behavior profile for them. Edible sheep tail fat was effectively fractionated by acetone crystallization at constant temperatures of 25, 15 and 5°C. In order to stabilize mutton tallow olein, antioxidant activities of some phenolic compounds including gallic acid, caffeic acid, catechin,quercetin, tannic acid, ellagic acid and salicylic acid were studied in tallow olein as a lipid system, at 150°C at 40, 60, 80, 100, 200 and 400 mg/L concentrations, by measuring induction time. Rancimat apparatus was employed as a mean to evaluate the antioxidant activity. The results indicated that gallic acid had the highest stabilizing effect on tallow olein while ellagic acid had the least effect as primary antioxidants. Among phenolic compounds investigated, only salicylic acid showed no antioxidant activity which is in contrast to all other antioxidant compounds. The results showed that, in tallow olein, the antioxidant activities of the ellagic and tannic acid are comparable to a-tocopherol whereas quercetin, catechin, gallic acid and caffeic acid are much more potent than a-tocopherol.

The aim of this study was to develop a biopreservation strategy for cold-smoked Caspian roach by the use of Lactobacillus casei previously selected for their capability to inhibit the growth of Listeria monocytogenes in this product. An application on commercial smoked Caspian roach was tested by spraying L. casei (104 CFU g-1) on slices smoked Caspian roach. Microbial and chemical characteristics were each ten days compared to a control during forty days of storage. No significant differences were showed in microbiological and chemical characteristics of inoculated slices with L. casei. The strain L. casei inoculated in SCR in a biopreservation goal exhibits some interesting properties: it is able to grow at high level without giving major quality changes in the product. In conclusion, biopreservation of SCR using lactic acid bacteria such as L. casei is a promising way to inhibit the growth of pathogenic bacteria such as L. monocytogenes with low effect on the quality of the product.

In this research, the effect of xanthan gum in three concentrations of 0.02, 0.05 and 0.07 g/kg of skim milk, containing 0.4% fat in production of Iranian white cheese was investigated. Two control cheeses was prepared, that one of them was full-fat control cheese without gum which was made of milk containing 3.2% fat and full milk.The other one was reduced fat control cheese that made of skim milk containing of 0.4% fat without adding any gum. The results of chemical, textural and rheological experiments showed the improvement of cheese's texture by increasing of xanthan gum. In this research, the full fat control one had the least quantity of rheological, textural features, ­, Gᵔ, and G* that showing the softness and desirability of texture. The treated cheese with xanthan gum of 0.07g showed the maximum similarity to full fat control cheese which by increasing of xanthan concentration, the textural and rheological features reduced. The reduced fat control cheese had the highest quantity of  ­, E, Gᵔand G* which showing the hardness and undesirability of texture. This study shows the desirability of xanthan gum as fat replacer in order to lowering the energy- producing extent of cheese as well as an improving factor of texture.

Edible emulsified films were made from pistachio globulin protein (PGP) (6 g/100ml), stearic fatty acid (SA) (2, 4 and 6% w/w protein), glycerol (1g/1g of protein), and emulsifier by emulsification method in order to improve water vapor permeability (WVP) and reduce water solubility of protein film. WVP of films reduced 38.5 to 42% by fatty acid addition and water solubility decreased slightly, too. Effect of SA on the oxygen permeability (OP) of emulsified films was determined indirectly by oil peroxide value measurements. OP values of the emulsified films were lower than that of PGP film, but the differences were not significant (P>0.05). Tensile strength (TS) and elongation at break (E) of PGP film were 9 Mega Pascal and 104%, respectively. TS and E of emulsified films were diminished 11 to 41% and 35 to 70%, respectively as a result of SA addition. Opacity of emulsified films (unfavorable sensory attribute) increased as function of SA concentration. Glass transition temperature (Tg) of films was measured by differential scanning calorimetry. Tg of PGP film was at 127.19°C and was not affected considerably by the SA addition.

Effect of gluten and emulsifier DATEM on rheological properties and specific volume of strudel bread was examined. Gluten in three levels (0, 1, 2 %) and Emulsifier in three levels (0,. /3,./5 %) were used. Samples proofed (Relative humidity 70%, temperature 42.c, time 55min) and storage in -17.c for 7 days. The samples thawed and then baked and specific volume was measured by seed displacement method. Rheological properties of dough were measured by brabender farinograph and extensograph. Rheological results indicated that gluten increase the dough strength and extensibility of dough. In addition, gluten and emulsifier increase specific volume of strudels. The best samples produced by 1 % gluten and. /3% emulsifier in combination.

High concentrations of salt in beach water and some industrial wastewaters resulted in an increase in water salinity, which causes difficulties in wastewater treatment. In this research, the effect of salt concentration (up to 30000 mg/L) on the treatment efficiency rates of saline wastewater in lab- scale batch conditions of Sequencing Batch Reactors (SBR) and Moving Bed Biofilm Reactor (MBBR) were investigated.The results indicated that at low concentration of salinity (0.5%) the removal rate of 94% in both MBBR and SBR has been achieved but in high concentration (3%) the efficiency of SBR (90%) was more than MBBR (83%). On the other hand attached growth in SBR has more potential to remove salinity. The rate of COD removal was 78 and 85 percent in MBBR and SBR, respectively. In the investigation of shock effect in salinity concentration of 50000 mg/L, the salinity removal efficiencies in MBBR and SBR has decreased to 56 and 68 percent respectively that has been reached to the previous level after 28 days.

At present one of the bread problems in our country, is its quality that has an important role in wastage. Among traditional breads, sangak has a better nutritional value and organoleptic properties, but unfortunately its shelf-life is short and stales quickly. Addition of rye flour to wheat flour IS one of the methods which is used in retarding bread staling. Since rye flour has a high amount of pentosan, its addition to wheat flour improves bread shelf-life. In this research the effect of adding rye flour to wheat flour on sangak bread shelf life also its influence on sensory characteristics of produced breads was investigated. At first rye and wheat four properties including moisture, ash, protein content, falling and zeleni number, and physical properties i.e particle size was determined. Then mixture samples were prepared by adding different ratios of 5, 10, and 25 percent of rye flour to wheat flour. Physical, chemical and rheological properties of the samples and mixtures were determined. Doughs were prepared and composite breads were baked. Finally, rye breads were examined organoleptically by a trained sensory evaluation panel, one, 24 and 48 hours after baking for acceptance and staling rate. The results indicated that: addition of rye flour to wheat flour did not have significant influence on dough rheological properties such as farinographic and extensographic properties, however sensory characteristics of samples were affected i.e increasing rye flour resulted in form, shape and porousness improvement of samples but it had a negative effect on upper and bottom surface properties, coincidence no change was observed about samples chewing ability and hardness.

Recent studies on physiological functions of oils containing conjugated linolenic acid (CLN), are indicative of the possible usefulness of these oils as a new type of the functional oils. In this study, the physicochemical properties of catalpa seed oil (Catalpa bignonioides), the source of conjugated linolenic acid, were investigated. Firstly, the seed composition was determined. It mainly consisted of protein (30.46%) and oil (12.74%). The oil was extracted by soxhelet method and fatty acids profile was determined by gas chromatography (GC). The predominant fatty acid was linoleic acid (40.48%) followed by catalpic acid (27.08%) and oleic acid (10.50%). The results showed that catalpa seed has high considerable oil which is rich in conjugated linolenic acid.

In this work, the effect of levels soy milk powder on rheological properties of dough barbary bread has been investigated. Therefore, soy milk powder was substituted for wheat flour at level of 3, 5, 7 and 10 percent. The rheological of dough were evaluated by farinograph, extensograph and amylograph. The results of rheological tests showed, that water absorption, stability, development time and softening degree was increased, but quality number was reduced in farinogram and resistence to extention and area under curves was improved and extensibility was reduced in extensogram. The results of amylograph test showed that gelatinization tempretur was increased,But maximum peak viscosity was reduced.

The aim of this study was to evaluate the quality of thawed silver carp in refrigerator. Silver carps were kept in -18°c for 3 months pre and post rigor mortis. After thawing they were kept in refrigerator for 12 days, meanwhile quality assessment of fishes was performed in days of 0, 3, 6, 9 and 12 by measuring chemical (FFA, TBA, TVB-N, Expressible moisture, pH and moisture contents), microbial (Total viable counts) and sensory factors (Raw and cooked fish). Freezing post rigor mortis and increasing storage time led to increase of FFA, TBA, TVN, Expressible moisture and pH contents, but decrease of moisture content. Although TVB-N elevated by increasing refrigerated storage, but its content for post-rigor frozen fishes was more than pre-rigor frozen fishes. Also, Total viable counts showed higher bacterial numbers in pos-rigor frozen fishes (p<0.05). Although silver carps were edible during 12 days, but sensory analyses of raw and cooked fishes indicated unsuitable quality of silver carps after 6 and 3 days in pre- and post-rigor frozen samples, respectively. Therefore, based on obtained results, freezing of silver carps before the onset of rigor resulted in increase of their shelf life during refrigerated storage.

Spaghetti is a good substitute for rice especially in Asian countries diet because it is cheaper than rice. Spaghetti’s traditional cooking is time consuming. Nowadays microwave cooking has been spread. In this study we aimed to assess traditional and microwave cooking effect on chemical and organoleptic characteristics of spaghetti. Samples were randomly selected from automatic and semi-automatic factories. Their physico-chemical characteristics were determined based on national standard (no. 213) after traditional cooking. The same samples were cooked by microwave in 5 and 8 minutes and then were assessed by trained sensory analysis panel. Statistical analysis was done and frequency, mean, median, standard deviation and diagrams were determined. The Mann-Whitney and three-way ANOVA tests were used to analysis the effect of production type and cooking time on spaghetti characteristics. There was no significant difference in chemical characteristics such as pH, ash and protein content between automatic and semi-automatic produced spaghettis. Automatic produced spaghettis had more acceptance considering their humidity, sensory evaluation scores and physical characteristics. The type of Production and cooking time significantly affects sensory evaluation scores but any effectiveness of cooking method (traditional or microwave) was seen on sensory evaluation scores. Production type and cooking type were significantly related. Cooing method had significant effect on sensory evaluation scores of automatically produced spaghettis. Cooking number was increased along with cooking time. Production type and cooking method had no effect on cooking number. Tukey test showed that mean cooking loss was higher in spaghettis cooked for 8 minutes.It was concluded that cooking time reduction, better color and lesser cooking loss is caused by microwave cooking in water. Microwave cooking has no effect on sensory evaluation scores, thus it can be a good substitute for traditional cooking methods.

Nanotechnology is increasingly being employed in the areas of food packaging. Public perception will be crucial to the realization of these technological advances. According to the amount of some of measurement variable isn’t available in some of the countries (scat dates), ingratiated different scheme. In fact in this schemes, analyzed with delete the test content scat dates. In this research investigated how to tendency creation to consume bread packaged in nano films for edit structural modeling of amount acceptance and ingredient fundamental in tendency creation for consume these products. Participants received some general information about nanotechnology, and specific information about three nano films packaging. Results show that in sum, participants were hesitant to buy bread with nanotechnology packaging. However, that nanotechnology packaging is perceived as being more beneficial than other packaging. Results suggest that social trust in the food industry is an important factor directly influencing the affect evoked by these new products. As suggested by the affect heuristic, affect had an impact on perceived benefits and perceived risks. Perceived benefit seems to be the most important predictor for willingness to buy.