نشریه پژوهش های علوم و صنایع غذایی ایران
سال سیزدهم شماره 6 (پیاپی 48، بهمن و اسفند 1396)

In this study, a mixture of milk protein concentrate, whey protein concentrate, skim milk powder, soymilk, margarine, butter and water was used for production of recombined UF-Feta cheese analogue. Variables were milk protein concentrate (8%, 9%, 10%), whey protein concentrate (0%, 1.5%, 3%), soymilk (5%, 10%, 15%) and margarine (0%, 5%, 10%). Textural properties of Samples were analyzed 3 days post-manufacture. The central composite design was employed and the results were modeled and analyzed using response surface methodology. Coefficients of determination, R2, of fitted regression models for different variables were varied in the range of 89.59-97.80 and the lack-of-fit was not significant for all responses at 95%. Hence, the models for all the response variables were highly adequate. The results showed that the optimum processing conditions for producing cheese with suitable hardness and cohesiveness and lowest adhesiveness were: 9.13% milk protein concentrate, 3% whey protein concentrate, 15% soymilk and 7.65% margarine.

In this study, the influence of different microwave powers (90, 270, and 450 W) and pulsation periods, i.e., On/Off times (30/60 and 30/120 ss-1) on drying rate and seed breakage of “Nemat” and “Hashemi” paddy varieties” was investigated. According to the results, the Midilli et al.'s model showed the best prediction accuracy for drying rate of the "Nemat" variety in the pulsation period of 30/60. Furthermore, the two-term model was found as the best model for "Hashemi" variety in the pulsation periods of 30/60 and 30/120 and for "Nemat" variety in the pulsation period of 30/120.The 270 W microwave power and 30/120 pulsation period can be recommended as a final conclusion of this study for drying “Hashemi” paddy variety. The breakage percentage at this condition was 19.1%. Breakage percent of the Nemat variety was more than 40% at all of the conducted measurements, indicating that this variety is not suitable for microwave drying. The final concluding massage of this study is that a pre-test should be conducted before applying the microwave for paddy drying.

Adequate consumption of ω-3 essential fatty acids (EFAs) has a positive impact on human health. EFAsenriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions developed by sonication method were subjected to various analyses as a function of hydrophilic lipophilic balance (HLB) and surfactant to oil ratio (SOR). Analyses were performed upon production and during 1-month storage at two temperatures (4 and 25 ˚C) in the presence (100 ppm) or absence of α-tocopherol. Increasing in HLB and SOR decreased the particle size and surface tension; while, increased the refractive index and viscosity. During storage, the particle size of α-tocopherol-loaded nanoemulsions decreased; whereas, that of α-tocopherol-free nanoemulsions increased in a temperature-dependent manner. Irrespective of the storage temperature, surface tension values of antioxidant-loaded nanoemulsions remained constant. However, their viscosity values increased. Antioxidant incorporation fairly increased the nanoemulsions stability likely due to partitioning at the interface. TEM micrographs confirmed the results obtained by static light scattering. The results of this study may help the rational design of functional foods using nanoemulsion-based delivery systems.

Various mechanical, enzymatic and chemical techniques are used to improve the quality levels of meat. Such techniques have disadvantages such as being time-consuming and damaging to the meat quality indicators. Ultrasound is used as an effective method to modify technological properties and tenderize the meat. The meat samples (Flank area) were put into brine solution or a mixture of the phosphate-brine solution under the ultrasound bath (at a frequency of 37 kHz) and probes (20 kHz) in 20, 25 and 30 minutes at 30, 40 and 50°C. The changes in the technological and textural properties of meat samples were then investigated. The results showed an increase in pH (from 5.55 for control up to 7.14), water-holding capacity (from 20.00 % for control up to 38.15 %), water-binding capacity (from 12.63 % for control up to 31.65 %) and a reduction in the drip loss (from 12.50 % for control up to 3.21 %), cooking loss (from 36.70 % for control up to 16.46 %), hardness and chewiness, whereas showed an increase in tenderness. In general, ultrasound treatment probe in a solution of mixed polyphosphate-brine was more efficient. It is concluded that ultrasound is an effective technique to improve the meat quality.

The present work describes the physicochemical and antimicrobial properties of active films developed by incorporating different concentrations (0.5, 1, and 2% v/v) of Satureja hortensis essential oil (SEO) and 3% (w/w) nanoclay into a chitosan- montmorillonite nanocomposite film. The tensile strength (TS) of the films significantly decreased and elongation at break (EAB) increased with the incorporation of SEO. The control film exhibited the lowest water vapor permeability. In addition, decreases in water solubility (WS) and transparency were observed with increasing the concentration of SEO. Thermogravimetric analysis (TGA) indicated that films incorporated with SEO exhibited a higher degradation temperature compared with the control. The structural properties and morphology of the nanocomposite films were examined by X-ray diffractometry (XRD) and Scanning electron microscopy (SEM). SEO-incorporated films were more effective against gram positive bacteria (Staphylococcus aureus and Bacillus cereus) than gram negative ones (Salmonella typhimurium and Escherichia coli). The results suggested that SEO, as a natural antibacterial agent, has the potential to be applied in antimicrobial biodegradable films.

Nowadays, demands for hydrocolloids which improve the rheological properties of foods as well as retain their properties under the influence of food additives have increased. In this study, dilute solution properties were employed to understand the molecular and conformational properties of Alyssum homolocarpum seed gum (AHSG), in presence of sucrose and lactose. The model of Tanglertpaibul & Rao was selected as the best model for the estimation of the intrinsic viscosity. It was shown that except for water, the solutions of sucrose and lactose are poor solvents for AHSG as indicated by a decrease in intrinsic viscosity, swollen specific volume, shape function, and coil dimensions. As the sucrose and lactose concentrations increased, the coil radius decreased. The reduction in the shape and swollen volume parameters in the presence of sucrose and lactose as compared to the sugar-free solution indicated the negative effect of the opted sugars on the molecular volume of the gum. Evaluations of the dilute solution properties of the gum in sucrose and lactose solutions revealed that the existence of a conformation tending to ellipsoidal shape and the probability of the conformation of random coil with no molecular entanglements in AHSG solutions.