مجله تحقیقات مهندسی صنایع غذایی
سال بیست و دوم شماره 1 (پیاپی 74، بهار و تابستان 1402)

Frozen yogurt is a kind of dairy dessert that combines the flavor of yogurt with the texture of ice cream. Stabilizers are preventing the formation of ice crystals due to their connection with a part of the water present in the product. In this study, the effect of 0.3 and 0.4% zedo, 0.1% carboxyl methyl cellulose (CMC), and 4% inulin on the physicochemical, rheological, and sensory properties of frozen yogurt containing nectarine was studied. The results showed that the brix, moisture content, density, and viscosity among treatments containing CMC and zedo gum in both amounts were not significantly different. But the highest moisture and the lowest density, brix, and viscosity were related to the control sample, and the lowest moisture and the highest density, brix, and viscosity were related to the sample containing inulin (p≤0.05). Overruns were lowest and highest in samples containing inulin and 0.4% zedo gum, respectively (p≤0.05). In control samples, the dripping time of the first drop was significantly lower than other treatments. But there was no significant difference between other treatments. None of the treatments had a significant effect on the scores for color, flavor, and texture of the samples (p>0.05). According to the results of this study, the use of 0.4% zedo gum in the production of fruit frozen yogurt containing nectarine is recommended.

Refractance Window is a novel drying system for producing high quality dry or concentrated foods. In this research, continuous refractance window drying was designed and built in Khorasan Razavi Agricultural and Natural Resources Research and Education Center, AREEO. In order to investigate the efficiency of the refractance window system, thin slices of apples and peaches were dried using this system and compared with the samples dried by hot air dryer and sun drying method. Then, drying time curves and physico-chemical tests (color, texture, vitamin C content) and taste evaluation were performed on the samples. The results showed that the drying method had a significant effect on the physicochemical characteristics of apple and peach fruits. The drying time in refractance window method was significantly less than that in the sun and hot air dryer. Soluble solids increased after drying. The highest content of vitamin C in apples and peaches dried by refractance window method was (8.41 and 6.83 mg/100 grams), respectively, which was 0.24 and 0.06% in apples, and 0.34, 0.17% in peaches more than that in samples dried by sun and hot air drying respectively. Also, the results showed that the force required to break the tissue of apple fruit in the method of drying with refractance window was 0.38 and 0.12%, respectively, and in peaches fruits was 0.30 and 0.15% less than that in the methods of sun drying and air drying. The results of the sensory evaluation showed that the product dried by the refractance window method had a higher score in terms of parameters of color, aroma, texture, and overall acceptance in compatre to the other two drying methods

Nanocubosomes are a collection of lipid particles that can be used in the preparation of nanoparticles. In this study, we seek to investigate the feasibility of producing curcumin nanocubosomes by intestinal lining and to investigate the effect of encapsulation on release profile and in vitro cell cytotoxicity. In this study, the antioxidant activity of encapsulated curcumin and its release profile in simulated gastrointestinal conditions through coated nanocarriers were evaluated. Two free and encapsulated forms in coated intestinal nanocarriers were studied to determine the effect of encapsulation on antioxidant stability. Then their effects on the cell viability of colon cancer cells were investigated. Character analysis reported that the mean particle size and zeta potential value of the nanocubosomes were 53.54± 9.17 nm and -7.46 ±4.54 mV. The results showed that nanocubosomes carrying curcumin could improve IC50 cytotoxicity by 1.55 times higher than free curcumin after 48 hours of incubation.

In recent years, edible coatings have received much attention due to their functional properties and have been used for a number of food products including fruits. Apricot is one of the fruits with short shelf life. Therefore, this study aimed to increase the shelf life of apricots at refrigerator temperature using edible aloe vera coating and to investigate its physicochemical properties. For this purpose, aloe vera gel was first prepared, dried and powdered. Then 0, 1 and 2% solutions of aleo vera powder were prepared and apricots of Rajabali cultivar were dipped for 5 minutes in solutions. The apricots were then packed in polystyrene containers and stored in the refrigerator at 4±1°C and 60±5% relative humidity. The samples were removed from the refrigerator at 0, 5, 15 and 25 days after storage, and physicochemical characteristics including weight loss, acidity, pH, firmness, vitamin C, mold percentage and color components were evaluated. Finally, the results were analyzed using a completely randomized design based on factorial test. The results showed that aloe vera gel at 2% concentration was highly effective in increasing the shelf life of apricots up to 25 days and the control samples without aloe vera coating had a significant decrease in quality and up to 50% moldiness. Therefore, it can be concluded that the use of aloe eera edible coating increases apricot shelf life, preserves physicochemical properties and decreases moldiness in apricots. In this way Rajabali apricots could be preserved for 15 days at cold stores.

In this study, amaranth seed flour was used in four levels (2.5, 5, 7.5, and 10%) as a fat substitute in the burger recipe prepared from veal. The characteristics of the produced burgers, such as chemical composition, texture, color, cooking loss and sensory properties were evaluated. The results of three replicates were analyzed in a completely randomized factorial design. The results showed that increasing the amaranth seed meal increased the protein, ash, and moisture content of the burger samples and significantly decreased the cooking loss (p <0.05). Texture evaluation of the burgers showed an increase in stiffness, gumminess, and chewiness, a decrease in cohesiveness, and no significant change in elasticity due to the use of amaranth flour in the burger formulation. The sensory evaluation showed that despite the negative effects of amaranth seed flour on all sensory properties of the burgers, the use of a maximum of 5% amaranth seed flour in the burger recipe is acceptable to consumers.

Humans are always looking for a way to preserve food from chemical, microbial, and food pathogen spoilage. The use of probiotics is facing challenges today. To get out of this impasse, probiotics can be converted into postbiotics and used in the treatment of various diseases. postbiotics provide a significant source of energy for colon epithelial cells and play a role in their growth and differentiation. To evaluate the antimicrobial effect, the postbiotic and was evaluated against the pathogens Escherichia. coli, Staphylococcus aureus, Penicillium notatum, and Candida albicans by Well Diffusion Agar method in measuring the diameter of the halo of non-growth. Skewness and kurtosis indices were used to check the normality of the data. In evaluating the antimicrobial effect of the postbiotic extract by diffusion method in the well and measuring, the largest diameter was formed in the concentration of 800 µl/ml in E. coli and Staphylococcus aureus bacteria. in Penicillium notatum and Candida albicans, a non-growth halo was observed after three repetitions. According to the results obtained from the present research, it can be concluded that Lactobacillus casei is one of the bacteria, whose postbiotics can have an inhibitory effect against pathogenic bacteria such as E. coli and Staphylococcus aureus. The results obtained in the measurements of the diameter of the non-growth halo of the evaluated pathogens showed a difference in the effect of the postbiotic extract.

The use of microwaves for heating in food industry is known as a safe alternative. In this study, microwave energy at different times and powers for fresh green leaf enzyme inactivation in green tea production was used. In the first stage, the blanching times (30, 60, 90 and 120 s) in the highest power (900 w) of the microwave were applied on green leaves; and in the second stage different microwave powers (500, 600, 700, 800 and 900 w) in the best time of blanching were used on green leaves. Quality characteristics including total polyphenol, antioxidant activity, chlorophyll and sensory evaluation were determined. The data were analyzed in a completely randomized design with four treatments (in first part) and five treatments (in second part) in three replications. The results showed increasing the blanching time (90 and 120 s), caused increasing in antioxidant activity and improved the sensory properties of green tea. Green tea treated in 90 and 120 s blanching did not show a significant decrease in quality after one year of storage. As the oven power for green leaf blanching increased, the taste, aroma and total sensory scores of green tea clearly increased. The amount of chlorophyll, polyphenols and sensory properties such as taste, aroma and total sensory scores of green tea treated in 500 w power was less than that in other treats. Green leaf blanching in 120 s with a power of at least 700 w showed the best result in terms of quality characteristics of green tea and its storage properties.

Plasticizers in plastic packaging materials, including terephthalate esters, can migrate into foods during storage, which can lead to safety and sensory food quality issues. In this study, the total migration rate of terephthalate esters from PET bottles into carbonated malt beverages was investigated at temperatures of 5, 20, and 40 °C during 30 days of storage in an acidic food simulant (acetic acid 3%). The total migration rate was evaluated after 10, 20 and 30 days. The data were in accordance with the Arrhenius equation, and the activation energy was studied at the above temperatures. The results showed that the migration process increased with increasing time and temperature. Changing the temperature from 5 to 45 °C significantly increased the diffusion coefficient of the migrating component (p < 0.05). The data had a good fit with the Arrhenius equation, and this model explained the dependence of the diffusion coefficient on temperature. A significant increase in activation energy was observed with increasing temperature. Migration of heavy metals under severe test conditions (40 °C during 30 days’ storage) showed that the migration rate of metals (Cr, Pb, As, Hg and Cd) was lower than the value specified by the European standard. In general, it can be said that the obtained data prove the safety of PET packaging containers for carbonated malt beverages, since the refrigerator temperature is the usual storage temperature for carbonated malt beverages.

In this research, nanoparticles of milk protein isolate (MPI) were produced by electrospraying method. In order to optimize the electrospraying conditions of MPI nanoparticles, the concentration of MPI solution (%wt.), the process voltage (kV), the moving distance of the particles between the tip of the needle and the collector (cm) and the pump flow rate (mL/h) in the form of a composite plot central (CCD) were investigated and modeled and analyzed by the response surface method (RSM). The results showed that the concentration of MPI solution had the greatest effect and the distance between the tip of the needle and the accumulator had the least effect on the diameter of nanoparticles. According to the results, by optimizing the concentration of MPI solution (2.5%wt.), pump flow rate (0.2 mL/h), the distance between the tip of the needle and the collector (15 cm) and voltage (17.5 kV), uniform MPI nanoparticles can be obtained. The images from the scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the success of the electrospray method in producing spherical nanoparticles with an average diameter of 329.3 nm and maximum uniformity in particle size distribution. Also, Fourier transform infrared spectroscopic (FTIR) analysis revealed the chemical structure of nanoparticles.

In recent years, there has been tendency among consumers to use low-calorie products with lower sugar content to promote their health. In this study, the effects of various bulk sweeteners such as isomalt, inulin and sorbitol in the formulation of dark chocolate as a sugar substitute on the rheological properties, melting behaviors and sensory properties of dark chocolate were compared and evaluated. The samples were subjected to steady and dynamic rheological analyses; melting parameters such as initial melting temperature, peak temperature, enthalpy and final melting temperature, as well as sensory analysis, were investigated using a 5-point hedonic method. The use of different types of bulk sweeteners had a significant effect on the rheological and sensory properties of dark chocolate; so, isomalt increased, while inulin and sorbitol decreased the apparent viscosity of the samples. Substituting sugar with sorbitol increased the gel-like behavior, while isomalt and inulin increased the viscous behavior of the samples. Bulk sweeteners also caused changes in the initial melting temperature and enthalpy, as well as decreasing the peak melting temperature of dark chocolate. Sensory evaluation also showed that the samples containing sorbitol had the lowest and those having sucrose had the highest score related to the total acceptance. Bulk sweeteners had different effects on the sensory and rheological properties of dark chocolate; so, the use of a mixture of these compounds to achieve an optimal formulation similar to that of the commercial sample is recommended.

Pectin, which is made from citrus peel and waste, is one of the most commonly used compounds in the food industry. For large scale production, a combination of membrane-vacuum filtering has been suggested as an alternative to traditional methods of purifying the acidic solution for pectin extraction. This study investigates the main factors regarding membrane filtering system for separation of fibrous materials from an acidic pectin solution under vacuum. These factors which include: filter-aid-particle size, amount of filter-aid (perlite) added to the solution, and the vacuum level, affect production efficiency, degree of esterification, and galacturonic acid content. Pectin extraction efficiency is an important criterion for evaluating the filtration system and test results showed that both perlite particle size and perlite-layer thickness significantly affect this dependent variable. By increasing the perlite particle size from 20 to 100 microns, the extraction efficiency has doubled. This is while increasing the perlite layer thickness from 1 cm to 2 cm cuts the efficiency in half (from 20% to 10%). The highest galacturonic acid content was obtained with 2cm perlite thickness and 20-microns particle diameter. The degree of esterification was affected by the extraction conditions, and results revealed that the extracted pectin samples have an esterification degree of 70±5%. The optimum extraction conditions were determined by the software to be: 2 cm perlite-layer thickness and 56-microns filter-aid particle size at a vacuum level of 0.38 bars. Findings of this study can be utilized in the industrial scale implementation of a biomaterial separation system using vacuum-membrane filtering.

Xylanase is one of the critical enzymes in the food, poultry feed as well as paper industries. This research aims to provide formulation and operating conditions suitable for spray drying of xylanase enzyme while maintaining enzyme activity. For this purpose, the xylanase was produced by Bacillus subtilis D3d strain using Brewers' spent grain (BSG) and yeast extract as carbon and nitrogen source in a 14-liter fermenter. After separating biomass and solid substrate by centrifuge, the supernatant was used as an enzyme source with a xylanase activity of 350 U/ml. Among the additives, manganese ions at a concentration of 10 mM had the most significant effect on increasing enzyme activity. Among the examined carriers, mannitol and magnesium sulfate showed the slightest decrease in enzyme activity. Magnesium sulfate and malt extract were selected as carrier and binder in concentrations of 20 and 5, (w/v) respectively. In the spray drying operation with an inlet temperature of 120°C, and an inlet feed flow rate of 4 ml/min, the enzyme activity was maintained and the powder with the 4.5% of moisture content was obtained.

Ohmic heating is a fast and uniform heating and produces a high-quality product with minimal changes in structural and nutritional properties, and it is also an environmentally friendly method that has been considered due to its beneficial properties. In this study, an ohmic processing system was developedthat used three independent factors such voltage gradients, electrode type (steel, brass and aluminum) and concentration of ohmic solution for mushroom cooking. Some factors for device had calculated such energy efficiency, exergy efficiency and exergy loss during the cooking and all data analyzed by SAS statistical program. The results showed that all independent factors had significant meaning on mushroom cooking. The highest significant was for voltage gradient and after this factor, electrode type and concentration of ohmic solution had the high amount for energy efficiency, exergy efficiency and exergy loss. The highest energy efficiency was equal to 79.57 joules, and the exergy efficiency was 61.36 joules, observed in the steel electrode and at a voltage gradient of 11.25. The highest amount of exergy loss was 39.6 at a voltage gradient of 5.7 and with the aluminum electrode. Based on results, it can be stated that the best type of electrode used was steel electrode and concentration 2 showed the best values.