مجله علوم غذایی و تغذیه
سال هفدهم شماره 3 (تابستان 1399)

The use of protein hydrolysate containing antioxidant peptides in the formulation of functional food has been increasing recently. The types and sequences of amino acids, the type of hydrolyzing enzymes and hydrolysis progress have some important impacts on the properties of protein hydrolysate.

In this research, the effects of pepsin and alcalase enzymes (E/S:1/10) under optimal conditions of each ones, were investigated on the extraction of antioxidant peptides from peanuts protein. Peanut’s oil was extracted using solvent extraction method and protein was precipitated at isoelectric point. The extracted protein was subjected to the pepsin and alcalase enzymes for maximum period of five hours. The progress of hydrolysis was considered every thirty-minutes using Ortho-Phthalaldehyde (OPA) method.

The results indicated that the most hydrolysis occurs after 250 and 90 min of hydrolysis for pepsin and alcalase, respectively and the values of free amino acid groups increased from 167.0 to 263.0 μM leucin/mg protein (for alcalase) and from 415.0 to 517.0 μM leucin/mg protein (for pepsin). Moreover, the antioxidant activity of protein hydrolysate was investigated based on DPPH and ABTS radical scavenging activity. By increasing the degree of hydrolysis, the DPPH and ABTS radical scavenging activity increased simultaneously. The maximum values of DPPH and ABTS free radicals scavenging activity were measured respectively, 5175.0 and 756.0 mMTE/mg proteins (for pepsin) and 3644.0 and 1087.0 mMTE/mg proteins (for alcalase).

The results indicated that the progress of enzymatic hydrolysis of peanut protein by alcalase and pepsin enzymes leads to producing more antioxidant peptides and the final products obtained can be considered as a candidate for producing functional foods.

For the precise designing of thermal processes, determination of thermal properties of foods is necessary. The specific heat and thermal conductivity are the two main thermal properties of food products.

In this research, the thermal properties of pumpkin purée in five levels of moisture (25, 30, 35, 40 and 45 percent), five temperature levels (25, 35, 45, 50 and 55ºC), different percentages of salt (0, 0.5, 1, 1.5 and 2%) and different percentages of sugar (0, 10, 15, 20 and 25%) were investigated.

The experiments showed that temperature and moisture caused increases in specific heat and thermal conductivity in pumpkin puree whereas the addition of salt and sugar caused reductions in both specific heat and thermal conductivity of pumpkin puree. In order to predict the effect of moisture, temperature, salt and sugar content on thermal properties of pumpkin puree, regression modes are used. Coefficient of Determination (R2) of specific heat capacity for temperature, moisture content, salt content and sugar content were 0.920, 0.941, 0.949 and 0.961, respectively. Coefficient of Determination (R2) of thermal conductivity for temperature, moisture content, salt content and sugar content were 0.851, 0.962, 0.956 and 0.979, respectively.

Temperature and moisture content have direct effect on thermal properties while salt and sugar contents have reverse effect on thermal properties of pumpkin puree.

Apple is one of the most valuable high quality products in the world that plays a specific role in the household food basket. Measurement of physicochemical and mechanical properties of fruits is necessary to reduce their wastes, increase quality, and reduce the products final cost in the transportation and handling, storage and processing industries.

In this study, some physicochemical parameters of three varieties of Iranian native apples (Golab, Shafiabadi, and Arous Meshkinshar) such as moisture, color, firmness, total soluble solids (TSS), acidity (based on malic acid), pectin, and pH were measured according to the standard methods.

The results showed that Golab variety has more pectin content, less sugar, more brix, lower pH, and higher firmness, while the Arous Meshkinshahr had low pectin, high sugar content, low moisture content, with lower firmness and brix. All three apple varieties had almost equal quantities of ascorbic acid (vitamin C) and little nitrogen. Shafiabadi variety was high in acidity. In point of color index, there was more greenness for Golab and redness concerned other two varieties.

In terms of measured physicochemical properties in this study, Golab variety due to also high percentage of pectin content might be used in industries such as canning, jam making; and having higher nitrogen content might be used in vinegar production. Shafiabadi variety due to higher soluble solid content and total sugar might be employed for production of dried apple and apple flakes.

Barley flour is one of the most nutritious, inexpensive and rich fiber food stuff that has many applications in food industries especially in confectionary products. Nowadays, fibers role is very important in human health and preventing diseases such as obesity, heart disease, diabetes and cancers. Sourdough fermentation with interaction of lactic acid bacteria and yeasts is considered to play a key role in the improvement of flavor, texture and shelf-life properties of bakery products. In this study, bacterial lactic fermentation was performed by Lactobacillus plantarum and Lactobacillus reuteri as a primer mixture used to improve the characteristics of barley bread.

In order to carry out the work, Lactobacillus plantarum and Lactobacillus reuteri were cultured in a medium containing water and flour and used to produce sour paste for the production of barley bread. The amount of staling and physicochemical and organoleptic characteristics of the product was determined after baking.

The results showed that the use of starters increased moisture content, pH, specific volume; decreased firmness and staling as compared to the control bread. Sourdough bread containing mixed starter gained higher organoleptic score as compared to the control bread.

The application of mixed starters consisting of Lactobacillus plantarum and Lactobacillus reuteri could be considered as a suitable starter culture for the production of sourdough and high quality bread.

Olive oil, as the major source of lipids in the diet, has a high amount of unsaturated fatty acids and biological components such as phenolic antioxidants that could prevent the destructive effect of free radicals and mutation of cell structures. The nonsaponifiable components of vegetable oils are good sources of specific compounds such as sterols, tocopherols, squalene, fatty acids, and other substances. The aim of this investigation is to determine the components in particular α-Tocopherol and β-Sitosterol through deodorization process and have been accumulated in the distillate tank.

Olive oil and distillates were provided by Roghan-e-Ziton Nabe Tavakoly manufacturing company. Sterols ad tocopherols were evaluated before and after the deodorization process and in the distilled tank. Qualitative and quantitative determination of sterols and tocopherols were conducted using gas chromatography and high-performance liquid chromatography after the extraction of nonsaponifiable matters.

The results showed that the deodorization process decreased the nonsaponifiable matters of olive oil such as sterols, tocopherols, hydrocarbons and some other components namely free fatty acids. Due to the lower temperature of the deodorization process for olive oil, in comparison to soyabean or sunflower oils, the accumulation of these components in the distilled tank were lower. There was no significant difference between sterol composition in distilled tank and oil samples.

Collected compounds in the distilled tank are valuable sources of vegetable sterols and α-tocopherol which might be employed in food and pharmaceutical formulation and industries.

Probiotics are living microorganisms that, by settling in the intestinal environment, inhibit the activity of noninfectious and pathogenic microorganisms. The main purpose of this study was to consider the probability of producing probiotic juice containing Lactobacillus acidophilus and Lactobacillus casei based on apple, cranberry and sour cherry mixture.

In the present research, Lactobacillus acidophilus and casie (0, 35, 50, 65,100% levels) were used at a density of 107, at the temperature of 4oc in juice made from mixed sour cherry, cranberry and apple. The physical, chemical, microbiological and sensory properties of the produced juice, during production period were all measured in the first, second, third and fourth week (28 days).

The number of probiotic bacteria in the juice increased over the time. Physicochemical properties such as brix, sugar, pH, acidity, turbidity and color had significant changes. Brix, sugar, pH decreased whereas acidity, turbidity of the juice increased. It was also found that the addition of bacteria has somewhat weakened the sensory (organoleptic) characteristics.

Among the samples, the sample containing 100% Lactobacillus acidophilus bacteria was identified as the best bacterial growth treatment and in terms of sensory properties, the sample containing 35% acidophilus 65% casei was introduced as a superior sample.

Caspian kutum (Rutilus frisii) is of great importance among consumers. The aim of this study is to investigate the changes in the fatty acid profiles of fish caught in east of Sari and west of Noshahr.

The studied fish (three fish from each gender) were purchased in winter and spring from Sari Shahid Beheshti Cooperative and the Veterans Cooperative of Noshahr (east and west of Mazandaran province, respectively). Biochemical analysis and fatty acid profile were determined by the application of gas chromatography using standard methods.

Stearic acid, oleic acid, and DHA were the highest in Sari in winter being the significantly different from other fatty acids (p < 0.05). Total fatty acids in male and female fish from Noshahr and male fish from Sari were significantly lower in spring than in the others, and male and female fish from Nowshahr contained relatively higher total fatty acids in winter. Maximum DHA values were higher than EPA in both sexes, seasons, and regions. The chemical composition of male and female fish did not differ significantly in both seasons and regions (p > 0.05). SFA percentages in both sexes and regions were generally higher in winter than in spring, while PUFA percentages in both sexes and regions were higher in spring than in winter. The percentage of ω-3 fatty acids (41.12%) in winter samples of Noshahr was higher than that (30.91%) in Sari, and it was higher in spring samples of Sari (55.27%) than that of Noshahr (17.29%). The lowest total ratios of ω-3/ω-6 were obtained in Sari (3.12) in male fish in winter and in Noshahr (3.23) in spring. The highest PUFA/SFA ratios were observed in Sari (1.9) and Noshahr (0.74) kutum in spring and winter, respectively.

Fish examined in winter contained more fatty acids (especially DHA and EPA) in the muscle and are therefore more important for human consumption. The two regions, two seasons, and two sexes had significant effects on body biochemical composition and fatty acid profile of Caspian Sea kutum.

Pumpkin powder is used because of its high nutritional value, highly desirableflavor, sweetness and appropriate color to improve the quality of bakery products and alltypes of cakes. In this study, Balangu seed gum was used to improve the characteristics ofpumpkin cake.

Firstly, the pumpkin cake batter containing different percentages ofBalangu seed gum (at four levels 0, 0.5, 1, and 1.5%) was prepared and their viscosity wasmeasured. The cakes were then cooked and the physicochemical properties including weight,ash, moisture, volume, density, crumb color, texture and sensory characteristics weremeasured.

Pumpkin cakes batter was a non-newtonian fluid and shear-dependent and timedependenttype. By increasing Balangu seed gum percentage in pumpkin cake formulation,the viscosity of batter increased (p<0.05). By increasing the Balangu seed gum from 0 to 1.5%, pumpkin cakes batters viscosity at shear rate of 40 s-1 ware increased from 16.93 to 32.21Pa.s (p<0.05). The moisture content and volume of cakes were increased by increasing gumpercentage (p<0.05). The increases of Balangu gum increased the brightness of cakes due toincreasing volume, in addition yellow colour of the samples decreased (p<0.05).

The increase in gum content, the firmness of the cakes was reduced, but theamount of springness, cohesiveness and resilience of the cakes increased significantly due tothe formation of prper and soft texture by gum in the cakes (p<0.05). The L*, a* and b*indexes for sample containing 1.5 % gum were 85.25, 3.491 and 50.25, respectively. Pumpkincake containing 1.5% Balangu seed gum had significantly more acceptability than othersamples (p<0.05).

 The increasing trend of food waste is one of the serious challenges in mostcountries, especially developing countries, to meet the sufficient food needs of society. In thisstudy, the thermodynamic performance of two traditional bread production chains isexamined. These two chains contain the fresh bread production and the double-baked breadproduction chain (without waste).

The calculations are based on the processing of 1000 kg of doughfor all eight bread chains. Lavash, Barbari, Tafton and Sangak breads produced had a mass ofabout 0.145, 0.410, 0.220 and 0.500 kg, respectively. In order to make an exergic comparisonbetween the bread production chains, the moisture content in both technologies for all Lavash,Barbari, Tafton and Sangak breads were 9.5, 34.1, 19.9 and 17.8 percent, respectively. Dataanalysis was done using two software “ees” and “ e! Sankey “.

The chemical exergy flows were found to be much larger than the physical exergyconsumed in all the bread chains studied. In the traditional bread production chain, lavashbread, baked twice, with the amount of 78.52%, Sangak with the amount of 76.06%, Barbariwith the amount of 70.64% and fresh Sangak bread with the amount of 70.29% had the bestexergy performance. The lowest total lost and irreversible exery were found in 1000 kg ofprocessed dough in the following breads: double-baked Lavash with the amount of (2910megajoules), Sangak bread with the amount of (3288 megajoules), fresh Sangak bread withthe amount of (3862 megajoules). And Taftoon bread double-baked (3921 megajoules).Lowest specific exergy loss and best thermodynamic performance was observed in doublebakedLavash bread (3.80), Sangak bread (3.91), Tafton bread (5.23) and Barbary bread(5.24), respectively. Combining exergy analysis and its application in the field of supply chainmanagement and management sciences are among the innovations of the present study.

Most of the energy loss (non-material) occurs during the cooking, cooling, andfreezing stages. Therefore, any progress in the production of traditional bread should befocused on the design of effective thermodynamic processes of these three stages and the useof appropriate technologies.

Replacement of synthetic pesticides and antifungal compounds with naturalones for reducing the decay of agricultural products is a challenge in the industry.

In order to investigate the effects of sodium alginate (Alg-Na) andpomegranate peel extract (PPE) on reduction of decay and improving the postharvest qualityof sweet lemon fruit, an experiment based on Completely Randomized Design (CRD) with sixtreatments and three replications was conducted. Treatments included Control (C), SodiumAlginate (Alg-Na 1%), PPE, PPE/Water ratio of 1:1, PPE/Water ratio of 1:2, PPE/Water ratioof 2:1 combined with Alg-Na 1%. Treated fruits were kept for 35 days at 20 oC and the fruitcharacteristics were evaluated at seven day intervals. Traits such as weight loss%, fruitfirmness (N), total acidity (TA %), pH, TSS%, vitamin C, fruit skin color (a*, b* and L*) andorganoleptic properties were measured.

The results showed that postharvest application of PPE and Alg-Na 1% hadsignificant effect on maintenance of sweet lemon in storage as compared to untreated fruits.The lowest fruit decay and microbial concentration was obtained in fruit treated with PPE andAlg-Na 1% as compared to other treatments. The lowest weight loss% was obtained in fruittreated with PPE and Alg-Na 1% and the highest was observed in untreated fruits. Fruittreated with PPE and Alg-Na 1% showed the highest fruit firmness at the end of storageperiod as compared to the control. The highest vitamin C at the end of storage was observedin fruit treated with PPE and Alg-Na 1%. The sensory test showed that consumer'sacceptability was increased by increasing the PPE concentration plus at Alg-Na 1%.

Our study suggests that the use of PPE combined alginate coating has thepotential to maintain sweet lemon quality and extend its postharvest life to 35 days.