نشریه نوآوری در علوم و فناوری غذایی
پیاپی 21 (پاییز 1393)

Gelatin has great attention in preparing edible films because of film forming ability and mechanical properties. The most disadvantage of gelatin films are high solubility and low water vapor barrier properties of these films. The objectives of this work is to determine effect of gelatin concentration and linseed lamination on mechanical and barrier properties of gelatin films. According to this study, gelatin content, linseed concentration influences on mechanical and barrier properties of gelatin films. Gelatin films that prepared with 7 g gelatin and laminated with 0.75 ml linseed oil showed lowest water vapor permeability, highest puncture force and Percentage of Elongation at Break. Lamination with linseed oil,cause significant reduction in film solubility. The lowest water solubility (40%)observed in films with 7 g gelatin and laminated with 0.75 ml linseed oil than non-laminated gelatin films.

Some domestic Damghan, Iran pistachio cultivars including: Akbari, Kaleghoui, Khanjari, Abasali and Shahpasand were obtained from Pistachio Research Institute of Damghan. The pistachio oil was extracted by organic solvent (n- hexan) and fatty acid composition were quantitated using gas chromatography (GC). The result showed that total fat content in pistachio cultivars were 52.486 – 60.647 %. The fatty acid were determined as myristic acid (0.0810- 0.1080%), palmitic acid (10.2275-11.10750%), stearic acid (1.1010- 1.2700%), arashidic acid (0.3855- 0.6300%), palmitoleic acid (0.8175- 1.0180%), oleic acid (48.961 - 55.2435%), linoleic acid (30.4820- 36.8840%), linolenic acid (0.3590- 0.8405%). Oleic acid has been found as the most common monounsaturated fatty acid. Linoleic acid had highest percentage among multi- bond fatty acids. There have been significant differences (p 0.05) among pistachio cultivars regarding unsaturated fatty acids. The ratio of unsaturated fatty acids to saturated ones has changed between 6.7- 7.4. Assessment of oxidative stability by Rancimat method result in the induction time in pistachio oil cultivars was 5.5 h (Shahpasand) – 7.69 h (Akbari).

With relatively high level of global fish catch, and following it, by the processing industries which have produced high volumes of by-products, very little effort has been done to produce hydrolyzed protein from this material, and to be discarded without any Environmental justification. If these biological compounds be used correctly, on the one hand caused reduce the environmental pollution due disposing of it and the other hand due to high protein value, are recyclable. In this study, first the effect of three different enzymes including papain, pepsin, trypsin(with a concentration of1.5 % of protein substrate) and its influence times (30, 60 and90 min) was investigated on hydrolysis rate of the big head fish viscera to protein recovery. Therefore, the recovered protein was used as a source of peptones to promote the growth of Lactobacillus plantarum and optical density was measured after0, 3, 6, 9, 12, 15, and18 hours incubation. Results showed that the papain enzyme in duration time of 90 minutes had the highest yield of hydrolysis degree and protein production. It also observed that the growth of Lactobacillus plantarum has been more in medium containing of peptone derived from enzymatic hydrolysis compared with commercial MRS medium as the control sample. The results showed that there is a good potential for producing hydrolyzed protein with high nutritional value from fish by-products.

In this study the influence of high pressure(20, 50, 80 and 110 Mpa)on the properties of limonene emulsions stabilized with different concentrations(10, 15 and20% by wt) of whey protein concentrate was investigated. The size of particles, the polydispersity index (PdI), and rheological characteristics of emulsions were analyzed. Based on the results, by increasing the concentration of whey protein concentrate, the size of particles and polydispersity index increased significantly. It is also observed that the size of particles as well as polydispersity index decreased by increase in processing pressure. By fitting the Herschel-bulky model on the experimental data of shear stress vs. shear rate, rheological characteristics of emulsions were evaluated. Results show that in all concentration and homogenization pressure emulsions exhibit shear- thickening behavior.

Response surface methodology is a series of statistical techniques that is used to design experiment, modeling and optimizing selected response variables. The aim of this study was to optimize the osmotic dehydration process using response surface methodology. The effects of variable temperature factor (35-50˚C), osmotic concentration (30-60% w/w) and solution to sample ratio (10:1 & 4:1) were evaluated on the weight reduction, water loss and solid gain. Result showed the optimum conditions were found to be at temperature of osmoticsolution30oC, syrup concentration 31% and solution to sample ratio of 5.7: 1. At these optimum values, weight reduction, water loss and solid gain were found to be 73.69 (g/100 g initial sample),78.62 (g/100 g initial sample) and 4.93 (g/100 g initial sample)respectively.

Dietary fibres are considered as prebiotic agents which can improve the viability of probiotics in food products during shelf life and causing health benefits. In this study, the effect of sugar beet fibre (0, 0.7, 1.5 and 2%) on rheological, physicochemical and viability of LactobacillusacidophilusLA5 in frozen yoghurt during 60 days at -18°C was investigated. Increasing theamount of sugar beet fibre leaded to increasing consistency coefficient and apparent viscosity values while decreasing flow behavior index of ice cream mixes. The maximum amounts of consistency coefficient (103.9 pa.sn) and apparent viscosity (1.44 pa.s) and minimum amount of flow behavior index (0.5) were associated to the sample containing 2% sugar beet fibre. pH and acidity values of samples with sugar beet fibre obtained in the range of 5.36-5.44 and 0.71-0.74% respectively which had significant differences with the control (5.53 and 0.55%). Melting resistance of the samples increased with increasing the amount of sugar beet fibre and maximum amounts of melting resistance was obtained for the sample containing 2% sugar beet fibre (92% vs. 20.85 for the control). Based on obtained results, increasing fibre content in frozen yoghurt had no significant effect on decreasing the number of Lactobacillus acidophilusLA5 during storage but the maximum final population of this organism was associated to the samples containing higher amount of sugar beet fibre(7.9-8.02 log CFU/g).

In this study, the effects of toast and steamed wheat germ (in four levels of 0, 5, 10 and 15% based on flour weight) on quantitative and qualitative properties of cupcake were studied. The results showed the firmness was decreased significantly in compare to the control except the sample containing 15% steamed wheat germ. However, the samples containing 5 and 10% of steamed wheat germ and the samples containing 5% toasted wheat germ had less stiffness in 72 hr after baking. Also samples containing 5 and 15% steamed wheat germ respectively had lowest and highest levels of firmness in one-week intervals after baking. Furthermore, theseresults indicated that specific volumes of two samples containing 5 and 15% toasted wheat germ were lower than the control sample. Results also found that an increase of more than 5%of the wheat germ of both treatments (toasting and steaming) decreased moisture. On the other hand the increase in the amount of wheat germ did not show a significant difference at 5% level in water activity. Finally, the samples containing 5 and 10% steamed and 5% toasted wheat germ had the highest score in the sensory evaluation.

In this study, colloidal suspensions with a concentration of 15% whey protein concentrate as wall material and d-limonene as the core was prepared in water. The emulsion was microencapsulated using spray drying and its particle characteristics were studied. In order to determine the stability of the wall and the release rate d-limonene, prepared microcapsules kept at room temperature for 6 weeks. Results showed that the addition of carbohydrate release rate d - limonene reduced. Scanning electron micrograph showed samples containing inulin and sucrose have roundness and smooth surfaces than samples with glucose and without carbohydrates. However, samples without carbohydrate were wrinkled and with gaps and holes in the surface.

The aim of this study was production of cumin essential oil nanocapsules to stabilize the essential oil by means of microemulsion technique. Microemulsification of essential oil with T20, T60 and T80 as surfactants and ethanol, propanol and butanol as cosurfactants were studied in surfactant:cosurfactant ratio of 1:1 and their phase diagrams were constructed. It was found that microemulsion zone was dependent to the surfactant and cosurfactant type. The experiments showed that the best T80:propanol ratio between 2:1, 1:1 and 1:2 for making the largest area of microemulsion was 2:1. Dynamic light scattering results showed that the particle sizes of the cumin essential oil capsules containing 1% wt. oil were less than 20 nm. Cumin essential oil release from microemulsion systems was more efficient than noncapsulated essential oil, making these systems good vehicles for drugs.

In this Survey, experiments were conducted to evaluate the quality and quantity of Diazinon, Malation, Methyl Azinofos pesticides in the local river fishes captured from Iranian Northern provinces. The Samples were caught from Common carp during Winter 2008 and Summer Autumn and spring 2009, were prepared and analyzed accurately using(AOAC,2000)and Gas Chromatography. The data obtained were subjected to one- way analysis of variance using spss statistical software. The results show that the four seasons mean concentrations of diazinon 0/35±0/70, malathion 1/16±2/35 of Azinfos methyl 0/74±1/45 mg/ kilogram. The highest concentrations of diazinon, malathion and Azinfos methyl has been observed in winter and spring.

In this study, the effect of microbial transglutaminase and sodium caseinate in nonfat probiotic yoghurt was investigated during 19 days storage at 5±1°C. The statistical analysis of results showed that transglutaminase and sodium caseinate significantly increased viscosity and water holding capacity of samples (P≤0.05). Enzymatic treatment also increased the rate of lightness (L*) and decreased yellowish spectrum (b*) whereas Sodium caseinate decreased the rate of lightness and increased yellowish spectrum in samples (p≤0.05). Also, the viability of lactobacillus casei significantly increased in sodium caseinate and transglutaminase treated samples in comparison with control (P≤0.05). The maximum amount of viscosity (2.68 Pa.s) belonged to enzymatic treatment. Thus, the use of transglutaminase and sodium caseinate is recommended in the production of nonfat probiotic yogurt.

The aim of this research was to investigate the possibility of using stevioside and tragacanth gum in replacing of sugar (sucrose) in Ghotab as an Iranian traditional candy. This research was carried out in order to find out the effect of replacing the sucrose by the ratio of 1 part of stevioside instead of 200 parts for sucrose according to the rate of sweetness of stevioside in compare with sucrose and addition of tragacanth gum at three levels (0.5, 1 and 5%) total (formula) on sensory and organoleptic qualities such as hardness, microstructure and color, using entirely random plan and average comparison by LSD. The results showed that a significant increasing and decreasing hardness by replacing of sucrose and addition of tragacanth, respectively (p≤0.05). In this respect, no significant differences was found between the reference samples and treatment containing 1% tragacanth and stevioside. No aftertaste was detected in the samples containing stevioside-tragacanth by the panelists, but more delicate samples were observed by addition of tragacanth up to 5%. structure of the texture revealed that by increasing of tragacanth content, the diameter, area of the air bubbles and prosity in Ghotab structure was significantly increased. However, the highest roundness and number of air bubbles were observed as well as, total in control samples. Color analysis of the samples showed that increasing of tragacant addition caused more color changes and browning index, in compare with the refrence. On the whole, it could be concluded that using of stevia-tragacanth in replacing of sucrose, could be a suitable was in order to produce a lower calories-Ghotabe.