مجله علوم و صنایع غذایی ایران
سال سیزدهم شماره 5 (پیاپی 54، امرداد 1395)

Kimchi is a general term for fermented vegetables.The aim of this study was to isolate and identify the Lactic Acid Bacteria involved in spontaneous fermentation of this product used biochemical and molecular methods. In this study, after successive culture on specific media, in order to classify of 85 selected isolates that according to preliminary experiments seemed Lactic Acid Bacteria, physiological and biochemical tests were done and then fermentation of 10 different carbohydrates were performed. Based on these tests, 85 isolates were divided into 10 groups. Some isolates were selected from each group and 16S rRNA was amplified using universal primers. Diversity of lactic acid bacteria in Kimichi was as followings: Lactobacillus plantarum (41.17%), Lactobacillus fermentum (9.41%), Enterococcus faecalis (3.52%), Enterococcus faecium (7.06%), Leuconostoc citreum (2.35%), Leuconostoc mesenteroides (3.52%), Pediococcus pentosaceus (8.23%), Wisella cibaria (24.70%). This fermented product has a wide microbial diversity which originates from natural microbiota presented in the raw vegetable. Lactic acid bacteria can produce a variety of acids and enzymes which play an important role in development of unique flavor and tasteTherefore, this strains that isolated from Kimchi can be used in the food industry.

Pomegranate fruits peel is an inedible part obtained during processing of pomegranate juice. Pomegranate peel is a rich source of tannins, flavonoids and other phenolic compounds. The palm syrup has unique odor and taste; it has high potential to be a new sweetener which is natural and chemical-free. In this study, the effect of aqueous extract of pomegranate peel adding at levels 10%, 20%, 30% and palm syrup adding at levels 2%, 4%, 6% on some physicochemical (pH, titratable acidity, total solid and viscosity) and overall acceptability of functional flavored milk was investigated during 21-day cold storage. The milk used for producing functional flavored milk samples was preheated at 50ºC, palm syrup and pomegranate peel extract were added to milk and were mixed for 5 minutes; then, The mix was heated at 75ºC for 15 minutes. After cooling at 25°C, flavored milk samples were hold at 4ºC. Acording to present research, with adding pomegranate peel extract pH, viscosity and total solid decreased (p<0.01); however, titratable acidity increased (p<0.01). Reduction in pomegranate peel extract levels improved overall acceptability of functional flavored milk samples (p<0.01). With adding palm syrup, titratable acidity (p<0.05) and total solid (p<0.01) decreased; however, pH and viscosity increased (p<0.01). With adding different amounts of palm syrup, there was no different in sensory properties of flavored milk samples (p>0.05). In terms of overall acceptability, functional flavored milk sample containing 10% pomegranate peel extract and 4% palm syrup gained the highest score in comparison with the other samples.

Nowadays, the investigations on sugar replacement with other sweeteners increased because of the relation of sugar consumption with some diseases such as blood pressure, dental decay, obesity and increment of the glucose and insulin which especially is dangerous in diabetic patients. In this study, sugar was replaced in 5 levels (0, 25, 50, 75 & 100%) with date puree in dunat formulation and physicochemical and sensory properties and shelf life of final product were assessed. Results showed that moisture and water activity values increased with more replacement of dunat was decreased in 75% replacement level. The oil uptake percent and special volume decreased from 50% and 75% replacement levels, respectively. Although L٭ and b٭ values of the dunat crust was decreased in 50% and higher replacement levels in compared with control sample, a٭ value was increased in 25% and higher replacement levels. While the a٭ value of the dunat crumb increased in 25% and higher replacement levels, L٭ and b٭ values decreased from 25% and 50% replacement levels, respectively. Results from panelist’s assessment also hadn’t significant difference with control sample up to 50% replacement level. Results from this study showed that 50% replacement of sugar with date puree in dunat formulation not only keep appropriate sensorial properties of products, but also reduce oil uptake in a significance difference in compared to control sample and in special volume and porosity, treated samples haven’t significance difference with control sample. Also increment in replacement level up to 50% of date puree, whilst increase moisture and decrease hardness of products in each three period times and regard to water activity value, lead to increase in dunat maintenances time.

Kimchi is a fermented herbal supplement, and appetizer that according to a raw material, process and geographical location are classified more than161 types. In this study, after kimchi production, isolation and identification of microorganisms was performed by molecular method. Lipase producing strain, Trichosporon asahii was isolated from kimchi sample (19.01 ±3 U/ml). The various medium components and culture parameters to achieve a more cost effective and economically viable bioprocess were screened and optimized using Design Expert software. PBdesignsare used to screen the most effective variables on lipase production that fermentation temperature and initial pHfor 48 hours 30. According to the results, extract of nigella sativa, olive oil, yeast extract, magnesium chloride, respectively, were the most variable. Variable particle size and pepton ehavenegative effect. The variable selection and optimization on was performed more efficiently. Finally, lipase activity was 35 ± 0.5 U/ml in the optimal conditions using a medium containing15% sativa extract, 10 g/l yeast extract, 22.5 g/l olive oiland25 mM/l magnesium chloride in the rotation speed of 150 rpm, respectively, as well as enzyme activityafter84/1times the optimal state before optimization. The kinetic parameters V (max) and K (m) was 0.367 mM / min and 0.53 mM through Michaelis–Menten Chart, respectively. Low Km indicates high affinity between enzyme and substrate and high Vmax demonstrates high catalytic performance of the enzyme

Gluten-free formulations are often supplemented with proteins to improve their quality. The objectives of this work were to assess the impact of different concentration of soy flour in addition to 2% of carboxy methyl cellulose on gluten-free bread quality parameters. Therefore, soy flour and rice flour were combined respectively in concentrations: 0% & 100%, 10% & 90%, 20% &80%, and 30% & 70%. Soy flour addition had had positive effect on farinograph properties of dough such as water absorption. Adding soy flour up to 10% caused positive and significant differences in physical properties of bread such as specific volume, crumb hardness, and porosity. Colorimetric factors, except for L*, were not influenced by soy flour. Pictures obtained from SEM showed that bread containing 10% of soy flour had the best texture and rice bread (100% rice flour) in the next order showed suitable and porous structure. Best score from organoleptic test was related to bread containing 10% soy flour getting the highest score in total acceptability. Generally, adding 10% soy flour resulted in reduction of undesirable properties of rice bread. However, increasing concentration resulted in negative effects on qualitative and sensory properties of bread.

Earlier toxicological studies demonstrated that acrylamide is carcinogenic and most acrylamide in food is formed when asparagine amino acid reacts with certain naturally occurring sugars such as glucose.Inhibition, even reduction, of acrylamide formation during processing of foods, can help to produce more healthy food and, consequently, promote food safety. The objective of this study was to investigate the effects of the autolysed yeast of Saccharomyces cerevisiae, vitamins niacin (B3) and pyridoxine (B6) on acrylamide formation in chemical model. In this study the effects of different concentrations (0.025, 0.25 and 0.5 mmol) of autolysed yeast of Saccharomyces cerevisiae, vitamins B3 and B6 on acrylamide formation were evaluated in a chemical model. The acrylamide level was determined by Gas chromatography- mass spectrometry (GC/MS). According to the results vitamins B3, B6 and autolysed yeast of Saccharomyces cerevisiae, could reduce effectively acrylamide formation and vitamin B3 at concentration of 0.5 mmol was the most effective (p<0.05). This study indicated that these three additives could significantly reduce the acrylamide formation.

The research aimed at mathematical modeling, kinetics and energy consumption of a hot air dryer with air recycle (0, 50%, and 75%). A hot-air dryer capable of recycling the exhaust air was used. The experimental data were fitted to standard thin-layer drying models in MATLAB 2007. The best model was selected according to the coefficient of correlation (R2), chi-square (c2) and root mean squares error (RMSE). These indices showed that the Midilli et al. model has the best fit for explaining the experimental data. The required energy was minimum at 0.5 m/s and 60˚C for 0%, 50% and 75% recycled air levels and was maximum at 1.5 m/s and 40˚C for all recycling levels. The hot-air recirculating system also reduced energy requirements and increased the drying time for aloe vera.

Present study were investigated to evaluation the quality parameters in drying of Aloe vera in three temperatures (40, 50, 60 °C), air velocity (0.5, 1, 1/5 m/s) and hot air recycling (0, 50 and 75%) in order to reduce waste. The results showed that with increasing temperature, the samples showed less resistance to color change. The highest difference dried gel was at 70 °C so that the increasing air velocity and temperature was increased this index. Also, the maximum change pH and shrink were obtained to be 0.58 and 86.2%, at 60 °C and 1.5m/s respectively in case without recycling hot air, while its minimum value 0.3 and 70.6% were at 40 °C and 0.5m/s in case with 75% recycling hot air, respectively. The maximum value of rehydration water was obtained to be 301% at 40 °C and 0.5 m/s in case with 75% recycling hot air, while its minimum value 199% were at 60 °C and 1.5m/s in case without recycling hot air.

Stabilizers are a group of bio-polymers which are used in ice cream formulations in order to create soft texture, uniformity, reducing growth of ice crystals and lactose during storage and may be used to increase resistance to melting. Among these factors are hydrocolloids. The aim of this study was to investigate the effect of substituting Salep with Salvia macrosiphon boiss seed gum (as a source of native gum) at levels of 0.1 and 0.2% on physicochemical and sensory characteristics of traditional ice cream. Physicochemical tests including resistance to melting, pH and specific gravity; and sensory evaluation including measurement of intensity of coldness, viscosity, liquefying rate and total acceptance were analyzed. Results showed that Salvia macrosiphon boiss gum was more and less effective than Salep. The highest resistance to melting (80.5%), liquefying rate (8.25) and total acceptance (6.6) belonged to the sample containing Salvia macrosiphon boiss gum. The highest pH (6.6), gravity (1.06), intensity of coldness (8.87) and viscosity (5.3) was obtained for the sample containing Salep. According to the results Salvia macrosiphon boiss gum can be considered as a substitute for Salep.

In this research, the effect of kombucha on physicochemical (pH, acidity, syneresis, viscosity, vitamin C and ethanol) and overall acceptability of yogurt samples were measured during 21 days of storage at 8ºC. Thus the amounts of 5, 10 and 15 %(V/V) of concentrate of kombucha layer grown up on black tea, with yoghurt starter, were inoculated to the milk containing 2.2 % fat. Meanwhile, the yogurt starter was applied for producing control sample. Fermentation in all samples was stopped when the pH reached 4.6. The results showed that during the storage, decrease of pH and increase of acidity were minor (p<0.01), and with raising the kombucha concentration, these changes were significantly less than control sample (p<0.01); syneresis in all samples (the same as control) increased while viscosity decreased (p<0.01) and increasing of kombucha concentration was caused increase of syneresis and decrease of viscosity (p<0.01); vitamin C decreased and ethanol increased very little (p<0.01) and as the kombucha concentration increased, the quantities of vitamin C and ethanol increased (p<0.01). Raising the kombucha concentration caused reduction of overall acceptability score in samples (p<0.01); and during storage, this score decreased (p<0.01) a little in comparison with that in control sample. After production and during storage, the best physicochemical and sensory properties was observed in sample containing yogurt starter and 5% kombucha concentrate.

Sour-orange (Citrus aurantium) seed oil was extracted by ultrasound-assisted, heat reflux, and Soxhlet extraction methods and their physical (melting point, viscosity, specific gravity, refractive index, and color) and chemical (acid value, acidity, peroxide value, iodine value, saponification value, and ester value) properties were investigated. Results showed although that some properties of the sour-orange seed oil such as acid value, acidity, peroxide value, iodine value, melting point, viscosity, and color were affected by the extraction method but its other properties such as saponification value, ester value, specific gravity, and refractive index were not affected by extraction method. In addition, the results of this study indicated that the sour- orange seed oil has some advantages such as low free fatty acid, low acid value, low peroxide value, low melting point, high saponification value, and high ester value. Therefore, the sour-orange seed oil can be introduced as suitable edible oil.

Pistachio plays an important role as exportation of Iran. The method of drying process has a remarkable influence on the quality of dried products. There are various methods for drying pistachio; however, choosing a suitable method of drying depends on reliability, healthiness and rapids. In current research, the effect of temperature in three levels of 40, 50 and 60°C and rotational speed of the dryer agitator in three levels of 5, 10 and 15rpm on reduction rate of drying period and drying kinetics of a common Iranian pistachio (Kalleh Ghoochi v.), in a new intelligent- vacuum rotary dryer, was investigated. This dryer was consisted of a cylindrical chamber and a twin electrical heater which dried products in a vacuum medium. The experimental data was analyzed in a statistical software "SPSS 10 " In accordance with the results, temperature and rotational speed of the agitator had a significant effect on drying period. When temperature and speed were 60°C and 15rpm respectively, drying period was short and equaled 185 min, but in temperature of 40°C and speed of 5rpm, drying period was long and equaled 325 min. Increasing the temperature also increased the rate of drying significantly. Results indicated that increasing temperature from 40°C to 50°C caused 25% decrease in the drying period and increasing temperature from 40°C to 60°C caused 39% decrease in drying period.

The aim of this study was to investigate the effect of frying temperature and replacement of soybean protein isolate (SPI) with wheat flour on chemical characteristics doughnuts. For this purpose samples doughnuts formulated replacement 3 and 7 percent SPI with wheat flour null and then fried at temperatures 150, 165 and 180 °C. Parameters moisture content, fat content, acid value, peroxide value and sensory properties were investigated. Statistical analysis was performed using a completely randomized factorial design. Means were compared using Duncan's test (p≤0.05) with each other. The results shown that, with increasing temperature and percentage replacement of wheat flour with SPI led to increasing moisture content and the oil content decreased in samples were doughnuts. Temperature increases from 150 ° C to 180 ° C in the process frying doughnuts Samples prepared with wheat flour, 3% and 7% SPI led to Increasing acid value oil absorbed in their 0.66, 0.64, 0.51 unit, respectively. Results of variance analysis showed significant effect type flour on the amount of hydroperoxides on oil is absorbed on case of donuts (p≤0.05). The results of the comparison means showed not follow the effect of the specific. The raters doughnuts Samples no significant difference in terms of our sensory evaluation (p≤0.05).

Crucian carp (Carassiu sauratus) is one of the economic species of Anzali wetland. In recent years, the demand of high consumption was found, because of its low price and high level of catch. This study focused on accumulation of heavy metals(Cd, Pb and Zn) in the edible tissues of Crucian.Sampling were done in 3 stations (West,Center and East) of Anzali wetland in 1391. In this study 10samples were collected from each site in the standard weight by grill net, randomly. After separation of tissues, preparing of samples were conducted by using of wet digestion method and mixed acid (HNO3/HCLO4).After filtration, the prepared samples were determined for Cd, Pb and Zn by using a flam atomic absorption spectophotmeter (AA),SHIMADZU model 680.The levels of metals were compared with the standard of American Food and Drug Administration (FDA) and the world Health Organization (WHO). The average concentrations of cadmium in the soft tissue of crucian were 0.07, 0.05 and 0.05 μ g / g dry base for West, East and Center of Wetland. For Zinc, average concentrations for West,Center and East were 58.45, 46.4 and 49.7 μ g / g dw, respectively. The result showed that,there were not significant differences (P>0.05) between stations about the Cadmium, Lead and Zinc in the tissues of Crucian. Concentrations of Pb and Zn were higher than of standars levels of WHO and FDA.

Dough products are traditional and inexpensive food products that their consumption has increased. Unfortunately in our country due to lack of adequate cultivation of durum wheat, lack of appropriate technology for the production of durum wheat semolina and economic conditions for import of durum wheat, producing high quality dough product is faced with many problems. Also the price of durum wheat is more expensive than other wheat cultivars. In order to provide Dough products with good quality, in this study we investigate physicochemical properties of semolina and cooking qualities of dough products made from three different varieties of hard wheat namely Morvarid, Chamran, Sayson and two breeding lines namely A-line and N-80-19 line that are easy available in Iran. Behrang durum wheat is used as reference variety. Some strong relationships exist between semolina characteristics such as protein, wet gluten, gluten index and dough product quality. Finally the results show that Chamran and N-80-19 cultivars based on key features of dough product (yellow color, protein content and cooking quality) have no significant difference with control sample and they can be introduced as the best wheat to dough products industry.

In this study, concentrated yoghurts were produced in four methods, Tuluq and Torba bags, packed in polyethylene containers and physicochemical such as pH, acidity, total solid, protein, fat and salt content, lipolysis, syneresis, proteolysis and sensory properties was evaluated with control yoghurt during 60 days storage period. In analysied samples yoghurt, pH were (3.89-4.56), acidity (0.94-1.70 g/100 g), total solid (12.5-37.5%), protein (3.7-12.5%), fat (2.9-17.9%), salt (0.2-1.3%) content and syneresis (18.5-61.5%). In the of all yoghurt samples, lipolysis increased during storage. Also, in concentrated yoghurts lipolysis was significantly (P>0.05) lower than control yoghurt during storage period. The percentage of pH 4.6-soluble nitrogen/Total nitrogen and Non-protein nitrogen/Total nitrogen in packed and control yoghurt samples increased significantly (P>0.05) during storage but in Tuluq and Torba yoghurts decreased during first 30 days and then increased significantly (P>0.05). Electrophoretic pattern showed that degradation of αs1- and β-casein were considerable in Tuluq yoghurt. This might be due to endogenous surface bacteria and yeasts activities on Tuluq bag. It was concluded that Tuluq yoghurt had high quality and long shelf-life and it is introduced as a valuable dairy product.