مجله تحقیقات مهندسی صنایع غذایی
سال هجدهم شماره 2 (پیاپی 67، پاییز و زمستان 1398)

Those who suffer from Celiac disease, a type of immunological disease, are not able to use and to tolerate gluten. The only way for them is to consume gluten free foods. The aim of this research was to find out some of the qualitative and textural properties of gluten-free sponge cake prepared with corn flour, fortified with pumpkin powder in four levels (0, 5, 10 and 15%). The results of this research showed that increasing of pumpkin powder in formulation of gluten-free cake, caused decrease in fat content about 18.5%, volume of cake about 51 % and baking loss about 13.2 %, but the moisture content, amount of ashes, apparent density and firmness of texture of product increased about 28.5, 42, 60 and 29% respectively (P<0.05). Results also indicated that L* and b* indexes decreased and a* index of cake shell increased with increasing of pumpkin powder (P<0.05). The results of sensory properties evaluation showed that samples containing 10% pumpkin powder received the highest score of sensory evaluation. According to the results obtained from this research, adding 23 % of corn flour and 10% of pumpkin powder to produce gluten-free sponge cake with desirable nutritional and sensory properties for patients with celiac disease, can be recommended.

Lime juice is used to add flavor to foods and to prepare soft drinks. Basically, fresh lime juice is stored at ambient, cold or freezing temperatures immediately after being packed. In this research, the effects of different storage temperatures on physicochemical properties (pH, acidity, total soluble solid, polyphenolic compounds, antioxidant activity, ascorbic acid, and color), microbial features (mold and yeast, total count) and sensory properties of lime juice during the storage period (45 days) were evaluated. The results showed significant changes in pH, acidity and brix of lime juice so that the pH of product decreased, but acidity and brix increased, as the storage temperature of lime juice increased. The range of these changes in the freezer was less than that in other types of storage temperatures. Antioxidant capacity and total phenolic content decreased slightly over time at different temperatures that were higher at ambient storage. The maximum reduction, from 52.66 mg/g in 1st day to 11.16 mg/g in 45th day, was recorded for ascorbic acid at ambient temperature. The storage temperature also had a significant effect on counts of mold, yeast and total bacteria in lime juice during 45 days of storage. The microbial count of lime juice increased as storage duration and temperature increased but it was higher in ambient and cold storage. The results of sensory evaluation indicated a significant decrease in taste, odor, color and overall acceptance of lime juice as duration of storage and temperature increased. These results suggested that freezing of lime juice could have positive effects on preservation method to prolong shelf life with minimum qualitative changes in lime juice.

To determine the mechanical behavior (creep) of potato under constant load, two potato cultivars were stored in two different conditions and the effects of storage time and temperature were investigated on creep behavior of the samples. Creep parameters included instantaneous elastic coefficient, delay elastic coefficient, initial viscoelastic coefficient, delayed viscoelastic coefficient and delay time. Two samples showed different mechanical properties, However, in both samples, there was a significant decrease (P <0.05) in all creep parameters except retardation time with increasing storage time. The effect of storage temperature on these parameters was also checked that results showed the reduction of these parameters in the non-technical storage especially in the Clone variety compared to the technical storage. A mathematical model showed as well the creep behavior of stored potatoes. Regression equations showed good results (R2 = 0.73-0.85) for the effect of storage time and temperature on creep parameters. The results of these equations showed that the Instantaneous modulus of elasticity parameter had the most effect on the creep parameters. According to these results, it can be said that in technical storage due to low temperature and controlled moisture than non-technical storage, there are better conditions for tuber durability than non-technical warehouse. The length of storage period of ‘Agria’ genotype is higher due to lower loss of moisture content and starch content and no sprouting compared to ‘Clone’ genotype. However, the tissue of the ‘Clone’ genotype is softened in comparison to the fresh sample less than two months in non-technical storage and less than three months in the technical storage due to the loss of moisture and the reduction of starch content that directly affected on tissue.

With increasing the obesity, food industry is trying to provide products with low calorie to consumers. Due to the function of fat and its role in the texture and taste of food, some suitable fat substitutes such as gums should be used. Zedo is gum exudates from: Amygdalus scoparia. Therefore, the overall objective of this study was to investigate the possibility of producing low fat yoghurt containing zedo gum at concentrations (0, 0.1, 0.2, 0.3, 0.4, 0.5%). Therefore, 6 treatments were designed according to a completely randomized design with factorial arrangement and physicochemical properties including acidity, pH, viscosity, syneresis, color indexes, amount of fat, protein and solid materials and sensory features were evaluated during 21 days of storage at 4 ºC. The results showed that using different concentrations of zedo gum had no significant effects on fat and protein content of the samples, but caused developing a slight increase in acidity and decrease in pH, compared to the control treatment. Adding the zedo gum to the samples and increasing its concentration significantly improved the sensory properties, decreased the syneresis, increased the viscosity and decreased brightness of samples (p <0.05). Results indicated that samples containing 0.4% of zedo gum had the highest overall acceptance score and considered as the superior treatment.

Physicochemical properties of rice change during storage that is known as aging. It needs 3 to 6 months for aging to be completed. In this project, steaming of paddy was done as an accelerated aging method. Steam curing was done for the fresh Shiroudi paddy in two moisture levels (20 and 17%) for 5, 10 and 20 min at atmospheric pressure in factorial randomized design. Then it was dried until moisture content reached as low as 11%. The paddy de-husked and polished in laboratory milling. The physicochemical properties of milled rice were determined and compared with control one. Some desirable changes in quality, attributed to treatment of rice by steaming, were similar to what could be seen in naturally aged rice: decreasing in solid loss, peak and breakdown viscosity (p<0.05), increasing in hardness of raw and cooked rice and head rice yield (p<0.05). Steam curing increased (p<0.05) all three gelatinization temperatures but had no visible effect on enthalpy. But it had an adverse effect on appearance of rice. With increasing of steaming time, chalkiness had been expanded (p<0.05). So, five min. seaming time could be done practically for accelerated aging of any Shiroudi paddy with different initial moisture.

The purpose of this research was to stop the proliferation of insects and microorganisms in dried fruits of fig cv. Sabz EStahban and to preserve the quality of the fruits by decreasing O2 and increasing CO2 and N2 in modified atmosphere packaging. Mold and yeasts, total counts of bacteria, commercial color, Lab factors, acidity, moisture, mold mycelium, alive and dead larva, alive and dead insects were evaluated. The properties were evaluated after 3 and 6 months storage of samples at 25 and 40°C. Gas treatments were: a) 70% N2 + 25% CO2 + 5% O2; b) 75% N2 + 50% CO2 + 5% O2; c) 20% N2 + 75% CO2 + 5% O2; d) 80% vacuum; e) control sample: 78% N2 + 0.3% CO2 + 21% O2. The effects of gas treatments were insignificant on color, acidity, and moisture, while they were definitely significant on granary pests such as larva, molds and yeasts, and bacteria. Reducing oxygen killed larva, fungi and bacteria. Control sample had the lowest dead larva. Modified atmosphere packaging and vacuum treatment caused significant depletion in granary pests in dried figs. So it can be a good replacement for methyl bromide.

Curing is one of the critical stages in postharvest wastage of garlic. To find out the suitable method of curing, a two-year examination has been followed. Garlic bulbs were harvested 7 days after cutting off irrigation and, from the point of diameter, were devided into three groups: less than 3.5 cm. between 3.5 to 5.5 cm. and longer than 5.5 cm. Plants cured with leaves of various shapes (standing and horizontal) and without leaves (upward and downward stem) to be dried up in the shade and were compared with the field curing: harvesting 35 days after the last irrigation. Results showed that after harvesting, the moisture content of various parts of bulbs with diameter longer than 5.5 cm. was more than what could be found in other two groups and the difference between pungency and firmness of bulbs was not significant. Among treatments, moisture loss in bulbs dried with leaves was higher than that in bulbs without leaves, and little difference was noticed in moisture losses among the bulbs of different sizes. Spoilage and bulb weight loss after four months, as well as color changes and pungency losses in field curing were significantly higher than that when curung occurred out of the field. Curing with the leaves faced with more color changes and weight loss than what could be niticed in curing without the leaves. We came to this conclusion that curing without the leaves was the best way of curing, but there was no significant difference between the quality properties and shelf life of bulbs with upward or downward stems.

In this research, the optimization of protein hydrolysis process with the pancreatin enzyme was performed to evaluate the effect of time (30-270 min), temperature (20-60°C) and enzyme concentration (0.25-3.25%) on DPPH radical scavenging activity and Fe2+ chelating activity by using the response surface methodology. Optimum conditions to achieve the highest DPPH radical scavenging activity (42.77%) and Fe2+ chelating activity (78.57%), were obtained at time of 141.1 min, temperature of 41.93 °C and enzyme concentrations of 2.14%. Under these conditions, the degree of hydrolysis was 36.8 ± 0.35. Comparing the antioxidant power of the hydrolyzed protein and the intact protein showed that the hydrolysis increased the antioxidant activity of the fenugreek protein, significantly. Then, the antioxidant properties of optimum treatment were investigated at concentrations of 10-50 (mg/ml). The highest DPPH radical scavenging activity (50.65%) and total antioxidant capacity (absorbance 1.65 at wavelength of 695 nm), hydroxyl radical scavenging activity (69.03%) and Fe2+ chelating activity (79.72%) were achieved at concentration of 50 (mg/ml) and reducing power (absorption 0.8 at wavelength of 700 nm) were achieved at concentration of 40 (mg/ml). The results showed that the hydrolysis of fenugreek protein with the pancreatin enzyme is an effective way to produce antioxidant peptides. So, the bioactive peptides, with significant antioxidant properties, can be used as potential substitute of synthetic antioxidants and as a protein supplement in food formulation to produce functional products with health promotion properties.

Date palm is one of the most important export products of Iran. The date pit is about 10% of the total weight of the date, and can be used in livestock feeding after being ground, and also in many processing factories. The purpose of this study was to find the effects of rotational speed, type of blades, feeding rate and temperature on the amount of powder produced in a model mill. The device consists of chassis, electrical motor, feed unit, mill unit with two types of blades and grading unit. The effects of rotational speed, blade type, feeding rate and temperature on physical properties (amount of pits that is cracked, half-broken, full crushed, powdered) and chemical properties (amount of oil, protein, fiber, ash) were investigated. Experiments were grouped into two independent parts. The first one was conducted to determine the effects of rotational speed (2400, 2600 and 2800 rpm), two types of blades (vertical and diagonal) and three temperature levels (50, 100 and 150 C˚) on amount of powder produced in the constant feed rate. After determining the speed, blade type and optimum temperature, the second group of experiments were conducted to determine the effects of feeding rate (700, 1200 and 1700 gr/min.) on the amount of powder produced. The experimental design was factorial based on completely randomized design with three replications. The results from the first group of experiments showed that the effects of temperature, speed and type of blade and their interaction on all physical properties were significant at 1% level. Maximum amount of pit powder was obtained at 2800 (rpm) blades speed, 700 (gr/min.) of feeding, 150 C˚ temperature using diagonal blades. Among the chemical properties, only temperature at 1% level was significant on the protein content of the date palm kernel powder.

The aim of this study was to evaluate the composition of fatty acid and qualitative characteristics of virgin olive oils produced in different provinces of Iran including Gilan, Golestan, Zanjan, Qazvin, Qom and Fars. Acidity, peroxide, extinction coefficient differences (∆k), fatty acid compositions were measured. The results showed that acidity, peroxide and extinction coefficient differences of most samples, except for the Fars and Golestan (F, Go3), and levels of fatty acids of all oils, except for miristic acid of Qom and Zanjan (Qo, Z2), were in accordance with the national and International standard of Olive Oil. The highest monounsaturated fatty acids, MUFAs (72.12-76.21%) were traced in samples from Zanjan, Golestan and Qazvin provinces which showed the lowest saturated fatty acids, SFAs (16.99-17.99%), poly unsaturated fatty acids, PUFAs (6.49-10.42%) and Cox indices (1.49-1.84%). Based on results obtained, the sample of olive oil of Golestan, Zanjan, and Qazvin (Go1, Qa1 and Z1) were in the highest quality categories and of Fars (F) was in the lowest quality categories with different indices from other samples. Since various parameters affect on the quantity and quality of olive oil and, beside that, the low quality samples can also be found in those provinces where high quality of olive oile are produced, the fatty acids profile alone could not be consider as sole factor to geographically classify the quality of olive oil, but it can be used as one of the important iindicators in quality classification of olive oil

In the confectionary and food industries, chickpea flour has a well-known situation and is at high risk of food fraud when economical issues are concerned. Low prices of wheat and split pea wastes flours compared to chick pea flour are the reasons that these materials are used as common frauds. Demanding of non-destructive methods of quality evaluation and also the increasing trend of the development and production of functional and portable optical equipment were the reasons why this research has been conducted. In this research, the potential of the spectroscopy (420-900 nm) with principle components analysis technique (PCA) and common preprocessing methods to discriminate the samples of chick pea, wheat and split pea flours on 5, 10, 20 and 30% mixing percentage has been studied. The mentioned method on detection of the split pea flour at 30% mixing percentage and lower was unsuccessful but on discrimination of the wheat flour at 30 and 20% mixing percentage was successful and on detection of 5 and 10% by applying preprocessing (SNV/MSC) was successful. The result indicated that there has been a possibility to define an index based on spectral data to detect the wheat flour in chick pea flour in 430-480 nm band, therefore there is a potential to replace experimental methods with fast and nondestructive spectroscopy (420-900 nm) with PCA.

Black cumin seed meal, a by- product of oil extraction, contains high levels of nutritional proteins, as well as desirable compounds such as antioxidants and fiber. In this research work, the effects of replacing wheat flour with black cumin seed (Nigella sativa) meal at the levels of 0, 5, 15 and 15% on the physical, chemical and sensory characteristics of sponge cake were investigated. The chemical analysis of black cumin seed meal showed that it had high content of protein (40%) and fiber (10%), so that increasing the level of black cumin seed meal from 0 to 15% in the formulation of sponge cake resulted in a significant (p<0.05) increase in the protein and fiber content of the samples. Addition of black cumin seed meal significantly decreased the content of moisture in the cake samples while significantly increased the fat and ash content and did not change the pH values of the cake samples significantly (p<0.05). Upon increasing the level of meal in the formulation, the volume and density indices of the samples decreased and increased, respectively. The color indices of L*, a*and b* of meal incorporated cake samples decreased, comparing to those of control sample (0% of meal). The results of texture analysis showed that increasing the levels of black cumin seed meal from 0 to 15% in the formulation, reduced (p<0.05) the firmness of cake samples. Finally, the results of physicochemical and sensory analyses of the cake samples showed that addition of black cumin seed meal at the level of 10% was the most appropriate amount for enrichment of sponge cake and thus formulating a functional product, since undesirable changes in the mentioned properties of the samples were detected upon addition of higher amount of meal.

The use of natural compounds, especially sweeteners, in flour products is of particular importance. Sorghum syrup as a nutritious natural sweetener can be a good sustitute for sugar, especially in biscuits and sweet breads. In this research, possibility of sugar replacement by sweet sorghum syrup (KFS2 cultivar cultivated at Gorgan research station) in two bakery pruducts, bis and sweet bread, was studied. For this purpose, different levels of sugar replacement with sweet sorghum syrup (0, 25, 50, 75 and 100%) were used. Physico-chemical properties, sensory test and color measurement were evaluated. The results showed that adding more than 50% of sorghum syrup, instead of sugar, reduced spread factor, increased thickness value, decreased lightness and yellowness, and increased redness of the biscuits and sweet bread. The results also showed that samples containing 75 and 100% of sorghum syrup had significantly (p <0.05) less volume and rigidity than those of control sample. The sensory evaluation test also showed that samples of biscuits and sweet breads containing 100% of sorghum syrup had the lowest score and samples containing up to 50% of sorghum syrup gained the highest score in terms of color, flavor, texture and overall acceptance (p <0.05). Based on the results, sorghum syrup can be replaced, up to 50 %, with sugar in biscuits and sweet bread formula without any significant change, compared to the control sample.