مجله علوم غذایی و تغذیه
سال هفدهم شماره 2 (بهار 1399)

Acrylamide is a carcinogenic compound which is formed by reaction between amino acids and reducing sugars. In this study, the possibility of acrylamide formation and different parameters related to sugar processing quality were investigated. 

  Different parameters for determination of physicochemical parameters such as pH, ash, brix, invert sugar, polarimetric sugar and color in samples were analyzed.  Acrylamide is a carcinogenic compound and is formed from the asparagine amino acid release with reducing sugars as carbonyl compounds during the Maillard reaction. In its formation, several factors such as the concentration of reducing sugars, temperature and time are effective.

Due to the danger of acrylamide in human diet and health, it is important to detect this compound during sugar production. The quantity of acrylamide was analyzed in different product produced in the factory, namely sugar beet, raw juice, thin juice, thick juice, molasses, and sugar crystals. The results indicated that the highest amount of acrylamide was found in thick juice samples (825 ng/kg).

The results of this study showed that although acrylamide is present in thick juice samples but in the final sugar the quantity of acrylamide is minute. Therefore, there is no concern about acrylamide in relation to sugar intake.

Meat is one of the main sources of animal protein that is required and used for human consumption. Chicken meat due to the availability and economic reasons has high consumption in human societies and freshness is the most important qualitative feature of chicken meat. A device is required and necessary for detection of fresh-chilled chicken meat from frozen-thawed ones.

In this research, a portable olfactory machine based on eight semiconductor metal oxide sensors was used for detecting the freshness of chicken meat. Ten grams of meat was uesd for each test followed by preprocessing and the data were analyzed by PCA and KNN methods.

Based on the results of PCA and KNN analysis, the freshness of chicken meat was detected with high accuracy by e-nose system. The loading and radar charts showed that the odor of chicken meat had the highest and lowest impact on the MQ136 and the TGS822 sensors, respectively.

The olfactory machine system is a very effective way to identify the freshness of chicken meat, which is based on the speed, low cost and reliability of the sensors.

Noodle is a product rich in carbohydrates without cholesterol, with a low sodium and fat content, but it is very poor in terms of essential amino acids such as lysine and threonine. Noodle has a particular popularity in the societies due to its cost-effectiveness, ease of use and the diversity of its forms. Due to the production stage of this product, additives can easily be added to the noodle formulation, therefore the newest enrichment in the industry is the use of rye flour, which has been studied in this research work.

In this study, by maintaining the constant level of transglutaminase enzymes and the amount of 20, 40 and 60g of rye flour in the noodle formulation, cooking quality and physicochemical properties of rye noodle were investigated and the chemical tests performed on the crossed- linked noodle with rye flour including moisture, ash, fiber, fat, protein and color. The AACC also conducted an examination of the rate of cooking loss, water absorption and swelling index. Sensory evaluation was also carried out based on the Hedonic method.

In terms of moisture, fiber, ash and protein contents, there were significant differences with the control sample. The amount of moisture and protein increased significantly by increasing rye flour and reducing the amount of wheat flour in the formulation, while the amount of minerals increased. By increasing the amount of rye flour, the brightness and yellowing decreased significantly, but the redness increased. In terms of sensory evaluation and general acceptance of noodles, 40g of rye flour has gained more points.

In this research, the cooking quality and physicochemical properties of rye noodle with different percentages of rye flour were investigated. The results indicated that by the application of transglutaminase enzyme and 40g of rye flour in the formulation the percentage of cooking loss, swelling index and water absorption decreased.

Natural beverages from vegetable origin are one of the most important and consuming products that have been widely introduced in the food program in recent years. Violet carrots can be used as a valuable source for the production of complementary foods because of the presence of phenolic compounds (antioxidants), vitamin C, carotene and other nutrients. On the other hand, turnip can also be an unexpensive and valuable source of fiber, vitamin and important minerals such as potassium. Beverages are one of the most important and widely consumed products that have been widely introduced in the diet in recent years.

In this study, 3 species of lactic acid bacteria (Lactobacillus fermentum, Lactobacillus paracasei and Lactobacillus plantarum) were used to produce probiotic beverages. Chemical, qualitative and sensory tests were performed in 3 replications. Fermented beverage with the yeast (Saccharomyces cerevisiae) without bacteria was used as a control sample. pH, alcohol and number of bacteria after 24, 48 and 72 fermentation were investigated. Sensory evaluation was also carried out to evaluate the acceptance of this drink by 10 pints.

The results showed that lactobacillus paracasei (7.79 log cfu/ml bacteria 72 h after of fermentation) had a higher acceptance than other bacteria. The value of pH was 3.8 and the amount of alcohol produced in the sample containing this bacterium was lower.

According to the total results, the sample containing Lactobacillus paracasei has the best quality among the other treatments.

Starch and its derivatives have several applications in food and other industries. Changes in the structural properties of starch affect their physico-chemical and functional properties.

In this study, after determination of starch, amylose and amylopectin contents of three Iranian wheat varieties (Alvand, light bak kras and Sirvan), modification of their characterizations were accomplished with cross linking creation with “epichlorohydrin” in (0.1%, 0.3%, 0.5% v/w) level and physical modification by ultrasounic waves in 28 KHz frequencies in two times (15 and 30 minutes) at 20 °C. Qualitative properties of the samples such as paste clarity, water binding capacity, viscosity, solubility, swelling power and freezing thawing stability (Syneresis) of native and modified samples were examined.The results were analyzed in a completely randomized design-factorial test and the means were compared based on the least significant difference.

The results indicated the solubility, swelling power, paste clarity and water binding capacity of physically treated starch varieties were increased as compared to the native granules. Whiles, starch modification with epichlorohydrin decreased solubility and consistency of treated starches. The changes of paste clarity and water binding capacity in chemical modified starch in comparison to the native samples are different in varieties. Viscosity of all modified samples in comparison to the native form was decreased and their synersis were increased.

  Modification treatments are effective in many qualitative properties of starch and effectiveness of different starch varieties on physical and chemical treatments are different due to difference in genetic characteristics of starch.

Oils and Fats are important components in human daily nutrition and have been consumed by man daily to a considerable quantity. The oxidative stability of oils and fats are affected by various factors namely oxygen, light, heat and prooxidant metals. The aim of the present investigation is concerned with the antioxidant activity of black tea extract and its synergistic activity with phosphatidy cholene (lecithin) on tail and tallow.

Black tea extract and lecithin were obtained and prepared. The antioxidant activity consisting of total phenolic content and radical scavenging effect were performed using tail-end tallow as the substrate. The stability was compared with the addition of BHT, the synthetic antioxidant at different concentrations. Commercial phospholipid (lecithin) was also employed to investigate the synergism between the phospholipids and the phenolic compounds present in black tea extract.

The results indicated that black tea extract at the concentration of 900 ppm and lecithin at the concentration of 500 ppm improved the peroxide value and induction period of tail-end tallow.

The addition of black tea extract and lecithin in combination improves the stability of oils and fats and might be employed and substituted for synthetic antioxidants.

Deficiency of fiber compounds in diets leads to constipation, cardiovascular diseases and various types of cancers. Therefore, in this research, grapefruit fiber was used as a hybrid compound in the formulation of sponge cake.

In this study, grapefruit fiber was first added to cake formulation at five levels of zero, 0.5, 1, 1.5 and 2%as a substitute for flour. The viscosity of the dough was measured by Brookfield viscometer. After making the cake, the specific volume, amount of porosity, texture, color components, and acceptability were investigated.

The results indicated that by increasing the amount of dietary fiber, the dough viscosity, fiber percentage, cake moisture, texture firmness and b * color were significantly increased, while dough density, pH, cake protein and L * color were significantly decreased as compared to the control sample. The specific volume and porosity of the cakes containing grapefruit fiber were not significantly different up to 1% of the control sample but decreased at higher levels of specific volume and porosity of the cakes therefore the difference was significant as compared to the control sample. Based on the results of the acceptance mediated by sensory properties, it was found that the sample containing 1% grapefruit fiber was the most accepted among the referees.

The result indicated that, adding 1% grapefruit fiber to the cake can improve the nutritional value of the cake while maintaining the quantitative and qualitative characteristics of the cake.

Fried foods, due to the desirable taste and flavor are quite popular. However due to the high amount of oil absorbed during frying, the use of coatings to reduce oil uptake in this food has been investigated.

In this study, pieces of chicken breast were coated in different concentrations of wheat flour (0, 3, 5%) in two groups of coating containing 0 and 1% NaCl. All the treatments were fried at 170 ºC±3 for 5 minutes. The quality and characteristics of all treatments were investigated.
 

The results showed that the moisture contents of the samples were maintained by increasing concentrations of flour and consequently the amount of oil uptake of the samples were decreased. The sensory evaluation results indicated that flour coating improved the texture of the samples (p<0.05) but the appearance and color scored  less and the flour did not have a significant effect on the taste (p>0.05). The evaluation of color indices showed that the brightness of the coated fried samples was less than the control treatment. Therefore fried treatments containing 1% NaCl had lower L index as compared to the control group and coated treatments with 5% wheat flour had the highest L index. In all the fried treatments, a index did not differ significantly, but b index increased considerably.

This study showed that the application of wheat flour lead to produce low fat fried foods without adverse effect on the sensory attributes of the final product.

Shrimp is one the most famous food with high nutritional value. Shrimp is undoubtedly one of the best-known sea foods and determination of appropriate methods for its packaging increases the shelf life of products and reduces the microbial load in all food processing plants.

The aim of this study is to implement nano packaging to evaluate its antibacterial characteristics, shelf life determination as well as evolution of quality changes during shelf life. The current study evaluates the antibacterial features of produced nanopackaging containing 1000 to 6000 ppm of nanosilver during 0,3,7,10,14,21 and 25 days concerned will total count, E.coli and S.aureus, sensory analysis and determination of size and distribution of silver nano particles using SEM and FESEM.

The results showed that there is a significant difference between the control and produced nanopackaging. Moreover, there were a significant difference between the antibacterial effects of nanopackagings on E.coli and S.aureus (P<0.05).

Sensory analysis of the product revealed that there is no significant difference between sensorya and quality characterristics of nano-packed shrimps and control shrimps.

The egg yolks have limited shelf life, therefore they are subjected to freezing or spray drying processes. Freezing and thawing can increase irreversible viscosity and reduce the solubility and can affect the emulsion characteristics.

Salt and sugar each alone and in combination with each other at the concentrations of 0, 5, and 10 percent were added to pasteurized egg yolks. The samples were divided into two categories including frozen storage temperature at -18ºC for 30 and 60 days and refrigeration temperature. Mayonnaises produced were tested 24 hours after preparation as a test sample at the moment of production and 3 months after preparation. The effect of sugar, salt and low storage temperature on egg yolks concerned with frozen and refrigerated forms in rheological properties and stability of mayonnaise were investigated and optimized by surface response methodology.

The percentage of salt on optimization was not affecting and sugar percentage at maximum concentration in every two categories of mayonnaise tested samples was selected as the optimized factor. Storage of egg yolk by freezing about 11 days for tested samples at the moment of production and about 26 days for the stored mayonnaise at 3 months, had the most desirability.

Pasteurized liquid egg yolk using optimized sugar concentrations and optimized freezing storage time with the aim of increasing the shelf-life can be frozen and can improve the rheological properties and stability of mayonnaise than prepared mayonnaise with refrigerated and non-sugared yolk.