نشریه فناوری های جدید در صنعت غذا
سال نهم شماره 3 (پیاپی 35، بهار 1401)

In this study, macroemulsions and nanoemulsions of rosemary essential oil were prepared under different ultrasound treatments (0, 2.5, 5 and 10 min). The stability of macro- and nanoemulsions of rosemary essential oil during one month of storage at 4 °C was determined through particle size measurement by DLS method. The antimicrobial activity of macro- and nanoemulsions of rosemary essential oil was evaluated by two methods of well diffusion and microdilution against four pathogenic bacteria. Also, their antioxidant potential was tested by DPPH free radical scavenging activity. The results showed that with increasing the ultrasound treatment time from 0 to 10 minutes, the emulsion droplets size decreased from 148.04 nm to 98.14 nm. An increase in macroemulsion and nanoemulsions particle size was observed during storage. The results of antimicrobial tests also showed that macro and nanoemulsions of rosemary essential oil had the highest antimicrobial activity against gram-positive bacteria, especially S. aureus. In the antioxidant activity evaluation test, the IC50 index of macro- and nanoemulsions of rosemary essential oil were estimated to be 36.43 and 45.86 g/ml, respectively. Based on the results of this study, the nanoemulsion of rosemary essential oil is suggested as a natural antimicrobial and antioxidant compound for using in foods.

In order to prevent physical damage, it’s recommended to harvest lentils at a humidity of 20%, and then reduce it to less than 12%. Remaining the plant on the field as the conventional drying method reduces the quality and quantity of lentil product. The main purpose of this study is investigation of lentil quality characteristics in different drying conditions in order to determine an optimal condition and design a specified dryer system which can dry lentil with sufficient quality characteristics. In this study, lentil grains were dried using a hot air dryer at four temperature levels of 50, 60, 70 and 80°C and three air flow velocities levels of 1, 1.5 and 2m.s-1 until the grain moisture reached to 12%. Then their qualitative characteristics were examined. Increasing the temperature and air velocity accelerated the samples drying time consumption. With increasing temperature, air velocity had less effect on the drying time of the samples. Also, with increasing both temperature and velocity factors, the required compression force increased. On other hand, with increasing temperature, the brightness of the samples (L) decreased and the color of the samples changed from green (-a) to red (+a) and changes in color parameter b showed that the intensity of yellow color in samples have been reduced. Increasing the temperature reduced the amount of protein and carbohydrates in the dried samples, in contrast, by increasing air velocity they were better preserved. Temperature had a greater effect on the protein and carbohydrate content of the samples than the air velocity. Also, the studied factors did not have a significant effect on the amount of minerals in the samples. Based on the results obtained in this study, it’s recommended to apply the drying process at lower temperatures (50 and 60 ° C) and maximum air flow velocity (2m.s-1).

Grapefruit (Citrus paradise L) belongs to the genus Citrus, a species of flowering plant in the family Rutaceae. Grapefruit peel can be used to produce valuable extracts or essential oils. Grapefruit peel has strong antibacterial and antioxidant properties. It is also used as an ingredient in cosmetics, perfumes, soaps and detergents. Grapefruit peel essential oil yield is 3.9%, which contains open ring hydrocarbons, alcohols, aldehydes, ketones, esters and alpha terpenoids. In this study, the properties of microencapsulated grapefruit peel essential oil with basil gum under the influence of homogenization at ultra turrax speeds of 10000, 15000 and 20000 rpm were investigated. The results of GC / MS analysis show that D-limonene (65.61%) and caryophyllene (8.59%) are the most chemical constituents of grapefruit peel essential oil. The rheological parameters were fitted by non-time dependent models and Herschel Bulkely and Power law models had higher R2 than other models. In addition to the viscosity diagram in terms of shear rate, the models confirmed the pseudoplastic behavior (shear thinning) of the microencapsulated grapefruit peel essential oil solutions with basil gum. The viscosity of microencapsulated grapefruit peel essential oil solutions decreased with increasing ultra turrax speeds. Also, the coating efficiency, emulsion stability and antioxidant properties of the samples were higher at 10000 rpm. No specific changes in functional groups were observed in the FTIR test with increasing ultra turrax speeds. DSC results show that the two regions of of endothermic peaks (19.4-83.3) and exothermic peaks (210.2-265.1) were related to water evaporation and material decomposition due to thermal decomposition of polysaccharides, respectively.

Regarding this fact that peroxidase (POD) activity is considered as one of the important qualitative parameters of apple fruits, in this study, the effect of cold storage on POD activity of Red Delicious apples were investigated during 60 days. Hyperspectral reflecting imaging in range of 400-1000 nm has been applied while POD of samples were measured according to standard methods. After discarding noises using principal component analysis (PCA), to improve spectrum, different primary pre-processing had been applied and their effects were investigated. The suitable model was obtained via Partial Least Square method (PLS). Important wavelengths were selected based on regression coefficient of the best model includes large absolute values of weighted regression coefficients (RC) and sequential predictions algorithm (SPA) and using various techniques were modeled. Concerning the PLS analysis, the best results were obtained through smoothing Savitzky-Golay pre-processing with mean square root error (RMSE) of 0.475 and 0.518 and coefficient of determination (R2) of 0.948 and 0.940 for calibration and validation data, respectively. According to RC and SPA, 9 wavelengths were determined as the best. In modeling by efficient wavelength, artificial neural network (ANN) and SPA Combined Model gave the best result. The results indicated that hyperspectral imaging could be considered as a valuable tool for POD activity prediction and the selected wavelengths could be potential resources for instrument development.

In this study phosphorylated and hydroxypropylated wheat starches were produced with 0.096 and 2.106% degree of substitution, respectively. The gel samples of the starches were prepared with concentrations of 8% and 12% at volumes of 7.5 and 15 ml. The gel samples were subjected under digestion process at simulated mouth and gastrointestinal conditions. The results showed that about 80% of the final glucose release from the starch samples were obtained within the first 15 min of digestion at the simulated intestinal condition. The amounts of glucose release for phosphorylated starch were approximately 6-11%, and for hydroxypropylated starch were 16-19% lower than that for native wheat starch after digestion at this condition. Fuzzy logic table look-up scheme was used in order to model the amount of glucose release from the starch samples. The fuzzy inputs (volume, concentration and the digestion time under the simulated intestinal condition) for each sample comprised of respectively 3, 3 and 13 fuzzy sets with triangular membership functions. Moreover, the amount of glucose release with 34 fuzzy sets and triangular membership function was considered as the output of fuzzy modeling system. In this research, the Mamdani’s inference system was used to conduct fuzzy set operations and the minimum T-norm operator and the center of gravity defuzzifier were used to produce each fuzzy rule. The results obtained from the fuzzy logic table look-up scheme modeling system demonstrated high proficiency (R2 = 0.991-0.995) of that for estimation of the amount of glucose release from the wheat starch samples at the simulated intestinal conditions.

The development of antimicrobial electrospun nanofibrous mats is one of the most recent trends in the field of food biopackaging. Herein, novel antimicrobial fibrous mats consisting of blend electrospun chitosan (CS)/poly(ε-caprolactone) (PCL) embedded with cinnamaldehyde (CIN) were fabricated via an electrospinning approach and investigated. Field emission scanning electron microscopy (FE-SEM) manifested that as-spun fibers were well-oriented with uniform diameters along their lengths. The physical interactions and hydrogen bonding between CS/PCL and CIN were verified by Fourier-transform infrared (FTIR) spectroscopy. This novel hybrid mat demonstrated excellent mechanical strength of 11.7 ± 0.93 MPa (CS/CIN(10%)/PCL) and achieved good water vapor barrier (WVP) performance. In vitro release assay also revealed that most of CIN loaded fiber mats were remained (73.2-78.1%) after 96h, demonstrating their durability. Furthermore, the electrospun nanofibrous mats containing the highest amount of CIN (CS/CIN(10%)/PCL) exhibited distinctive antibacterial activity towards Gram-positive Listeria monocytogenes and Gram-negative Escherichia coli bacteria. This study gives insights to design new fiber-based antimicrobial nanomaterials of interest in food packaging exploits.