نشریه فناوری های جدید در صنعت غذا
سال دهم شماره 1 (پیاپی 37، پاییز 1401)

The main objective of this study, the effect of infrared (IR) on popcorn produced at IR power 550, 450 and 350 W and sample distance from the radiation source of 10, 20 and 30 cm on changing some physical and sensory properties of popcorn (papping properties, sensory evaluation, surface morphology (SEM) and temperature profile) was investigated. It was observed that typically with increasing IR power and decreasing the distance of the samples from the infrared radiation source, the popping yield, volume expansion rate and popping percentage increased significantly (P <0.05), and the beginning of popping commencement, expansion residue and the bulk density decreased significantly (P <0.05). In SEM analysis, the texture of popcorn produced by IR, after increasing the volume and changing the starch structure of the samples, turned into a honeycomb, and this factor increased the starch volume of the samples and naturally increased the total volume of samples after the popcorn production process by IR has occurred. It was found that the valley of popcorn produced by IR increases the size of pores by reducing the sample distance from the IR source and increasing the power of the IR lamp, or in other words, the number of holes per unit area decreases. The highest heat generated in IR-produced popcorns was measured at IR power 550 W and a distance of 10 cm at 274 Cº. The highest sensory evaluation score given by sensory panels was assessed in IR-produced popcorns at IR power 550 W and distance of 10 cm. According to the results, the IR popping process has a high efficiency to produce popcorn.

Microbial contamination of spices and medicinal plants at various stages of the production leads to low quality and shorter shelf life. As a result, sterilization is required to decrease the microbial load. The purpose of the current study was qualitative comparison of the two methods induction heating technology (115, 135 and 155 °C for 45, 60 and 75 s) with gamma irradiation (5 and 10 kGy) for sterilization of cumin seeds. For this purpose, microbial load (total microbial count, mold and yeast and coliform), total color differences and essential oil content were studied as quality properties of cumin seeds. After examining the influence of various induction heating system treatments on the specified parameters, process optimization was carried out by using the response surface methodology. Optimal decontamination conditions were obtained with a combined treatment of 151 °C -46 s. In these conditions, total microbial count, mold and yeast, coliform, total color differences and the amount of essential oil were 3.06 CFU/g, 3.1 CFU/g, 2.28 CFU/g, 4.15 and 2.57%, respectively. The optimal points of the induction heating method were validated and compared with the gamma irradiation method. The results showed that gamma irradiation caused in the greatest decrease of microbial load (1.52 CFU/g) (10 kGy). The least amount total color differences were found at 5 kGy treatment with a value of 2.76. No significant effect on total color differences was identified between gamma irradiation (10 kGy) and induction heating system. The highest and lowest levels of essential oil were found in the induction heating treatment (151 °C -46 s) and gamma irradiation (5 kGy), with the values of 2.45 and 1.7 %, respectively. According to the results of scanning electron microscope, induction heating led to a change in the surface structure, pores and cracks in the seed surface compared to gamma irradiation.

Adulteration in food products is regarded as a main challenge in food industry, which adversely affects food quality and health. Owing to pleasant taste and antioxidant properties, pomegranate paste is one of the most valuable and desirable foods in the people diets in some countries. As a luxury and expensive food, it is likely to be adulterated by some producers or distributors for the more profits. In this study development and application of machine olfaction system using array of gas sensors to detect adulteration in pomegranate paste was aimed. Principal Component Analysis (PCA), Linear Discrimination analysis (LDA) and Artificial Neural Network (ANN) methods were used to analyze response of the sensor arrays. Based on the results, PCA with two components PC1 and PC2 described 94% of total data variance. In LDA method, the classification accuracy of pomegranate paste samples was 97.65% which higher than PCA method. The values of correlation coefficient (R2) and root mean squared error (RSME) of neural network in ANN method using the structure of 6-9-7 were 0.984 and 0.0018 respectively. This study reveals that the electronic nose device can be used as a non-destructive tool to classify and detect adulteration of different classes of pomegranate paste.

In this study, potato starch was etherified by monochloroacetic acid and then was cross-linked by Sodium triphosphate. Thereafter, chitosan nanoparticles were added to increase the antimicrobial properties and was used in mayonnaise with reduced fat in three types of formulations, with 30, 40 and 50% reduced fat. In rheological studies, from 4 different levels, carboxymethylated starch at the level of 7.6, cross-linked at the level of 0.2, containing nano-chitosan at the level of 20% was selected by creating a high complex viscosity. The average particle size of nanochitosan was 79 nm and its zeta potential was positive and equal to 36.6 mV. The results of the flow behavior of mayonnaise samples after 40 days showed that, due to the increase in shear rate, more changes were made in the apparent viscosity of samples 40 and 50% than 30% sample. In the study of viscoelastic behavior, the highest value of Ǵ was determined for 50% sample during the 46 days storage period. Evaluation of the thixotropic behavior of the samples revealed that, the substitution of modified starch increased the thixotropic properties of the mayonnaise emulsions. Study of stress changes in mayonnaise samples implied that, the highest stress was related to 50% mayonnaise sample compared to control. The flow behavior estimation of mayonnaise revealed that with increasing the amount of modified starch along with increasing the coefficient of stability, the amount of stress also increased. Emulsion stability assessment of the samples implied that the samples 30 and 40% have the highest degree of stability. Microbial evaluation of the sauce samples shows a decrease in the total microbial count of the control from 228.3×102 to 55.9 ×102 in the 30% sample, after 46 days.

Finding a nondestructive method, for rapid evaluation of bread crumb changes during storage, helps researchers to assess the effect of different additives on quality properties and shelf life of bread. Therefore, in this study the changes of bread free vibrational parameters including natural frequency, damping ration, zero-crossing rate, average, standard deviation, peak, energy and entropy were evaluated in comparison with bread textural and sensorial properties on 0, 2 and 4 storage days. Finally, a predictive model was developed to determine the textural characteristics of bread (firmness, chewiness, cohesiveness and springiness) using support vector regression with three kernels linear, quadratic and radial basis function. Results of correlation coefficient of evaluation showed strong relationship between vibrational parameters with textural variables. In addition, in general, considering the error of three kernels as well as the correlation coefficient, the linear kernel performed better than the other two kernels in predicting textural properties. Therefore, the results of this study demonstrated the suitability of vibrational properties for determination of textural Characteristics of bread crumb during storage.

One of the cellulose derivatives is microcrystalline cellulose (MCC), that is widely used in food and pharmaceutical industries as excipients, anti-caking agents, emulsifiers, binders, disintegrating agents, dispersants, emulsion stabilizers, thermal stabilizers and carriers for fast drying and tableting agents. In this study, MCC was prepared from dried Lucerne (alfalfa) waste fibers of which the pigments were already extracted as food colorants. This cheap and renewable raw material was converted to MCC by conventional methods including dewaxing, de-lignification, bleaching and acid hydrolysis. Commercial microcrystalline cellulose (Avicel PH-101) was used as reference compound for comparative studies. For characterization of prepared MCC, particle size analysis (PSA) was performed. The results of the particle size analysis showed mean particle size of the prepared sample was approximately 26 µm. Fourier Transform Infrared spectroscopy (FTIR) of prepared MCC showed similar spectra to that the commercial MCC. Thermogravimetric analysis (TGA) of the prepared MCC in comparison to that of the commercial MCC contain three main stages of weight changes. TGA behavior of both samples are matching together. In order to study the crystallin structure of the prepared MCC, X-ray diffraction (XRD) analysis was carried out. The XRD pattern from prepared MCC was similar to that of commercial one. The SEM images of Lucerne (alfalfa) and the commercial MCC showed that microcrystals of both MCC have similar morphology. They both represent an irregular, agglomerated, and elongated morphology. Overall, the properties of the prepared MCC are comparable to those of the commercial type, and can be used as food and pharmaceutical additives.