فصلنامه پژوهش های صنایع غذایی
سال بیست و ششم شماره 2 (تابستان 1395)

Functional foods are among the topical issues in nutrition, nutritional foods, medicine and health fields. Considering the unique properties of Spirulina platensis, it can be used to enrich yogurt. In this research, the effect of micro algae; Spirulina platensis in the concentrations of 0.3, 0.5 and 0.8 percent was examined on selected physicochemical properties such as pH, titratable acidity, dry matter, protein, syneresis, iron, color and viscosity (on the 0, 7th, 14th, 21st days) and sensory properties (on the first and last days of storage time) of probiotic yogurt containing 10 and 13 % spinach. The results showed that various concentration of micro algae increased titratable acidity, without any visible changes in pH and reduced syneresis. Spirulina platensis was effective on the values L, a and b color of yoghurts, also reduced viscosity of samples. Protein and iron of the yoghurts that enriched with micro algae increased. In overall acceptability evaluation, probiotic yogurt with 0.5 % algae and 10 % spinach had the highest score. The mentioned treatment was described at a desirable level in related to physicochemical properties examined; so, this treatment was selected as the best treatment.

In this study, the antioxidant activity of essential oil (EO) of clove in comparing to BHT was investigated using DPPH free radical scavenging, β-carotene/linoleic acid and reducing power methods.The EO was added to aqueous Hydroxypropylmethylcellulose (HPMC) and then HPMC film was prepared, in first stage the effect of clove EO as a natural antioxidant in mechanical/optical properties and water vapor (WVP)/oxygen permeability (OP) of films was investigated. Subsequently, the antioxidant activities of films against soybean oil oxidation were evaluated during 60 days storage at 40 °C in a dark place by measuring the peroxide value (PV). Results of DPPH and reducing power assays showed that, higher antioxidant activity was observed for clove EO than BHT. The EO causes a significant decrease of WVP and OP of films. Also, addition of clove EO into HPMC film led to decrease of transparency and mechanical properties. In general, elongation percentage from 23.6 to 17.9%, tensile strength from 27.3 to 12.3 MPa and elastic modulus from 537.5 to 479 MPa in comparing to control film (without antioxidant) was decreased. HPMC film containing clove EO revealed a notable antioxidant activity against the soybean oil oxidation in comparing to control film (P

In this study, the effect of substituting resistant starch on qualitative properties of sponge cake with the aim of preparing functional cake with lesser calories and minimum quality loss was evaluated. The effect of resistant starch fiber at levels 5, 10, 15, 20, 25 and 30% (by weight flour) on various properties of cakes including moisture, height, color and texture were tested. The results showed that fiber cakes, compared to control samples contained more moisture but showed no significant change in the color and height parameters. Also, the results of the texture profile analysis indicated that increased levels of fibers caused significant changes in some parameters of texture instrumental. Based on the results of sensory tests and despite all the differences with the control sample, cakes containing resistant starch achieved high scores of consumer satisfaction. Also, after calculating the energy contents of selective and control samples, cakes containing resistant starch had lesser energy contents.

In this research, squash (Cucurbita pepo) fruits were cut into 0.4 cm thick and 4 cm diameter slices. After blanching, squash slices were dehydrated in a hot air dryer, under air temperature of 60±0.5°C until moisture content of 0.1065 kgw/ kgdm Dehydrated samples were stored at 4°C until their use in the rehydration process. Squash slices with specified weight were rehydrated by immersion in distilled water at different temperatures (25, 50, and 75°C), which was agitated at different speeds (0,100, and 200 rpm). For all experiments, solid to water ratio was kept at 1:25. At specified time intervals, namely, 1, 3, 5, 10, 20, 40, 60, 120, 180, and 300 min the squash sample was removed from the water, and the weight, moisture content and rehydration indices of the sample were determined. The texture characteristics were examined over a 180 min period. The results showed that moisture content, WAC and RA of squash slices increased, whereas DHC and texture firmness decreased with rehydration time. In general, for all rehydration conditions of squash slices, the highest water absorption rate occurred during the first minuts of process, then this rate decreased. The maximum of moisture content, WAC and RA and the minimum of DHC, force and stress, were observed in squash slices rehydrated into 75°C water which was agitated at 200 rpm.

UF-Iranian white cheese is a fresh cheese that is consumed shortly after production. Salt has a positive effect on dewatering of coagulum, improvement of taste and strength or texture of this kind of cheese and with the loss of free water and as a result, reduction of water activity, increases the shelf-life of cheese. But due to the sodium chloride salt intake on human health harms such as increased blood pressure (Hypertension), increased risk of heart disease, vascular and renal and osteoporosis, cheeses produced using a low-salt or salt substitute can be considered as appropriate. In this study, ability to reduce sodium levels in Iranian white cheese during dry salting, in terms of the mechanical and rheological properties were investigated. Five treatments including mixtures of different proportions of NaCl and KCl with ratios treatment [A or control (3% NaCl), treatment B (2% NaCl 1% KCl), treatment C (1.25% NaCl 1.25% KCl), treatment D (1.5% NaCl) and treatment E (1.5% KCl 0.25% NaCl)] were prepared in Hamedan Pegah Dairy Factory and was investigated over 60 days of ripening by stress relaxation, cutter and colorimetry tests. The results showed that overall stiffness, strength, hardness and elasticity of the sample, increased from the 3th to 30th day and decreased from the 30th day until the 60th day. Also with reduction of the amount of total salts NaCl and KCl in each treatment, decreased their strength and coherences and samples were softer and weaker and disintegrated, so that treatment A and treatment E, respectively, had the highest and lowest values of stiffness and strength. In total, according to the results of all tests and parameters, treatment B was the nearest and most similar treatment to treatment A (control), that only in one parameter had a significant difference with treatment A, and therefore without having a negative effect on the mechanical and rheological properties of cheese, control treatment can be replaced by treatment B.

Today, imported gums are used as stabilizers in mayonnaise industry. The purpose of this study is to identify and evaluation of Persian gums’ potential and its’ mixture effect with xanthan gum on the quality characteristics of mayonnaise. After determining the optimum concentration for sample with 100% Persian gum, other samples were prepared with mixture of both gums at levels of 25%, 50%, 75% and 100%. After 1 day quality tests were performed. color measurements showed that increasing in Persian gum level from 0 to 100 caused decreasing in lightness and increasing in a* and b*in samples with different levels of xanthan and Persian gum. Other experimental data showed that the maximum synergistic effect was observed in 1:1 xanthan: Persian gum. This sample had the highest stability, firmness, cohesiveness and adhesiveness among all of the other samples. The results of rheological test indicated that the sample with ratio of 1:1 had higher G’ and parameter A, which were significantly different than other samples. This study shows good potential for using mixture of Persian gum and xanthan gum in mayonnaise due to their synergistic effect that can be addressed for related industries.

The purpose of this study was to model oil uptake during deep-fat frying of potato slices pretreated with 0.1 and 0.2% carboxymethyl cellulose concentration and 40 kHz ultrasound frequency for 15 minutes. Potato slices were cut into 1.2×1.2×4 cm3 rectangular pieces and after performing the pretreatments, frying process was done at three different temperatures of 150, 170 and 190ºC for 1, 2, 3 and 4 minutes. Oil uptake in the fried potato pieces was decreased using ultrasound and edible coating pretreatments in both concentrations of carboxymethyl cellulose and this reduction was statistically significant compared to control samples. The use of ultrasound together with carboxymethyl cellulose led to further reduction in oil uptake compared to the other samples. A number of empirical proposed models with two models in the literature were used for modeling oil uptake. Average correlation coefficient between experimental and models data was high. The influence of temperature on maximum oil content and specific rate of oil uptake was investigated using the Arrhenius equation. In addition, sensorial analysis showed that ultrasound and its combination with edible coating pretreatment improves sensory characteristics of fried potato slices.

In this study, ultrasound and osmotic dehydration pretreatments were used to produce good quality fried potato strips. Effect of the pretreatments (ultrasound at 28 and 40 kHz frequencies and osmotic dehydration at salt solution concentrations of 2 and 4%) on apparent density of potato strips fried for 4 minutes with intervals of 60 seconds at temperatures of 150, 170 and 190°C were investigated. Also, changes in the apparent density were modeled in terms of frying time, oil content and moisture content in order to control the optimal process conditions and improve the final quality of fried products. Results showed that osmotic dehydration and its combination with ultrasound pretreatment significantly reduced the apparent density of the pretreated samples. In addition, experimental data were well fitted by proposed models in this study having high correlation coefficients.

Using soy bean lecithin in chocolate need further revisions and requires adding replacement without any threat on society health due to its negative effects on the lipid oxidation during storage of chocolate, causing darkness, unpleasant taste and more important that all above, because of the usual frauds of crass industrialization in the food industry. In this research, effects of substitution of ester of mono-dyglycerid citric acid (Citrem) were assessed on the microbial, physico-chemical and organoleptic properties of milk chocolate. Preparation of chocolate with Citrem was done at different levels of 0.4%, 0.5% and 0.6%. The control samples made with 0.5% lecithin. The samples were stored for 3 months. Organoleptic and physicochemical properties were analyzed every month. The results showed that the microbial enumeration of treatments was not affected during 90 days storage. Also, the maximum acidity (1.8 mgKOH/g) and peroxide values (2.2 meq/Kg) belonged to control samples in the end of storage period. The minimum acidity index (0.9 mgKOH/g) were seen in the samples containing 0.5% Citrem in days 30 and 60. The minimum peroxide value (0.6 meq/Kg) observed in control treatments in day one. Acidity and peroxide values of samples produced with lecithin were higher than chocolates with citrem. On the basis of consumer acceptance, chocolates containing Citrem, received higher sensory scores compared to the control treatments. Generally, the results indicated that by incorporating Citem in chocolate, it is possible to produce product with desirable flavor and sensory properties that have significant role in the quality of chocolate.

the aim of this study was to evaluate the effect of post-harvest dipping treatment of methyl jasmonate on quality and shelf life of fruit in "Camarosa" strawberry cultivar. In this experiment, the strawberry fruits were dipped thoroughly in methyl jasmonate in five levels (0, 25, 50, 75 and 100 µM( as a treatment. Factorial experiment in a completely randomize design (two factors: different concentrations of methyl jasmonat and storage in coldroom for 12 days) in four replications. Qualitative characteristics shuch as soluble solids, titratable acidity, total flavonoids and antioxidant capacity were measured. Results showed that all of the concentrations of methyl jasmonat caused significant differences in the amount of total soluble solids, titratable acidity, vitamin C, pH, total phenol and flavonoids, antioxidant activity and weight loss compared to the control. so that in the treated fruits the amount of weight loss and pH was less than control and the amount of total soluble solids, titratable acidity, vitamin C, total phenol, flavonoids, antioxidant activity was more than control. Also the highest levels of total phenols and flavonoids and antioxidant activity were observed in fruits treated with 100 µM methyl jasmonate and the lowest levels of this traits was recorded in control during storage.

The present study investigated the effect of lipid coatings and atmosphere of packaging on instrumental and sensory properties (texture and color) of raisin. Raisins were coated with carnauba- wax (0.5% w/w) and stearic monoglyceride (0.5% w/w) and raisins packaged under two different atmospheric conditions: normal and vacuum. The changes occurred in the moisture content, texture, color parameter (L*, a*, b* and ΔE* values) and sensory attributes of raisin were determined during 12 weeks of storage at 20°C, 35°C and 50°C. Instrumental and sensory attributes were correlated with Pearson Correlation Coefficient. In all samples, the hardness value increased along with storage time, while the moisture content decreased. But presence of lipid coating on rainsin significantly (P

Surimi is a Japanese term used to call mince which a major part of its soluble compounds may be emitted during rinsing and its remained miofibril proteins are mixed with preservatives before freezing. In Aras reservoir more than 1000 tons of this fish were harvested annually, in this study 300 kg fish were collected from Hassan Kandi and Shibloo fishing stations in 1393 and transferred to Iranian Artemia Research Center. These fish were bone separated, washed and processed by additives according to standard methods. Qualitative factors such as color, odor, flavor, pH, preservation time and marketability were compared with control fish (natural muscle) in three treatments and repeats. Surimi production efficiency from fish muscle was obtained as 43± 5 (w w %). The results showed that Surimi has lower and bright color, lower odor, better flavor, lower pH and eight days more preservation duration (at 4ºC) than fish muscle. Marketability of surimi was completely significant (P

Color is one of the important factors considered as an important factor in evaluation of food products qualification. The aim of this study was to compare the effect of four coating layers to the pomegranate fruit on the color changes of juice fruit and choosing the best type of cover to keep this quality factor. Four types of coating layer including Aloevera gel, chitosan solvent 1%, pomegranate peel extract and liquid paraffin were used then the samples were storage for 105 days at 4 ° C. The spesifid samples were taken once every 35 days and the color parameters of the samples, including lightness, angle Hugh amounts, redness, yellowness and blueness, the color saturation and browning index were determined. Data were analyzed using SAS statistical software, and the results showed that the coating layers and storage time on all studied color parameters Except browning index, had a significant effect in the level of 5%. The results also showed that, samples covered to Aloevera jel after of 105 days storage with decreas value lightness 40.78, yellowness150.26 and hue angle 42.52 degree in comparetion with other coating treatments increased the preservation of color properties in pomegranate.

Fruits harvesting techniques are the most important factors that affected on olive oil quality. In this study, effect of fruit damage at harvest time on extracted oil quality of two olive cvs. Zard and Roughani were investigated. Fruits were harvested by hand and by rattan (the common method). Thereafter, hand harvested fruits were divided also into two subgroups, without damage (control) and artificial damage. Olive oil quality characteristics including free fatty acid (FFA), peroxide value (PV), coefficients K232, K270, total chlorophyll, total carotenoid, total phenol, total flavonoid, antioxidant capacity, IC50 and anti-raical efficiency (AE) were measured. Fruits damage during harvesting or artificially increased FFA and PV of both olive cvs. Zard and Roughani oil. In addition, a K232 and K270 coefficient of oil was more than control. Damaged fruits especially those harvested by rattan have showed less oil chlorophyll and carotenoid content than control. The highest amount of total phenol and total flavenoid content was observed in control fruits. Although, no significant differences were found among treatments. Overall, fruits damaging during harvest time and before oil extraction reduced some antioxidant compounds and increased FFA and PV, which resulted in declining olive oil quality, however no significant difference was found between damaged and intact fruits for oil antioxidant capacity.

In this study, yield, purity, degree of hydrolysis and molecular weight of protein produced by hydrolyzation of tomato seed using alkali at pH=10, 11 and 12, enzymatic extraction by Alcalase 2.4L and Flavourzyme 500L at concentration of 1 and 2%, and the combination of enzymatic and alkaline extraction were evaluated. The results showed that extraction yield of Alcalase- hydrolyzed protein was significantly higher than those for others (p0.05). However, it was found that alkaline treatment after enzymatic hydrolysis leads to decrease in purity of protein and extraction yield, compared to single treatment with enzyme. By the way, molecular weight of protein hydrolysates decreased proportional to extend of enzymatic treatment. Therefore, protein hydrolysate from Alcalase had peptides lower than 10 kDa due to the higher degree of hydrolysis. In general, protein extraction was influenced by pH, the type and concentration of enzyme that was used.

Fresh mushrooms have low durability. Therefore, use of practical solutions to increase their shelf-life, is necessary for improvement of production. The aim of present research is study the effects of salt fortification by vacuum impregnation on physical characteristics and some qualitative characters of hot-air dried mushrooms. At first, the condition of salt fortification by vacuum impregnation was used at 5, 15 and 25minute process times for mushroom samples. Then, pre-treated and control mushroom samples dried by warm air at 60 C. Finally, shirinkage, porosity, Re-hydration percent of dried textures, color and hardness were determined. The results indicated that vacuum time had significant effect on shirinkage, porosity, re-hydration percent of dried samples, hardness and color change. By increasing vacuum time, hardness and shirinkage decreased, their color improved and porosity increased. Also increasing vacuum time had similar changes on traits with lower amounts. Re-hydration percent of textures, decreased by increasing vacuum time and increased via increasing atmospheric pressure time. Finally, it is revealed that, optimal vacuum time and atmospheric pressure time for dried mushroom quality conservation, were 20-24 and 22-25 minutes, respectively.