Foam-mat drying of shrimp: characterization and drying kinetics of foam

The effects of water: shrimp ratio and xanthan gum (XG) concentration on characteristics of shrimp foam were investigated.  Foams were prepared from shrimp puree by adding several xanthan gum concentrations (0.1, 0.2, 0.3 % w/w), water: shrimp ratios (2:1, 3.5:1, 5:1 w/w) and whipped for five minutes.  Incorporation of 0.2% w/w XG with 3.5:1 w/w water: shrimp ratio was selected because of having better characteristics of produced foams and then dried at 50, 60 and 70°C.  Results showed that stability and density of foam increased with increasing xanthan gum concentration.  However, increasing water : shrimp ratio caused to decrease in stability and density of foam.  As the temperature increased from 50 to 70°C, the drying time decreased to 55 minutes.  Only the falling rate period could be observed during the drying process.  The average values of effective diffusivities of dried samples at mentioned temperature range were estimated to be between 3.24–6.49×10-9 m2 s-1.  The Arrhenius equation with the activation energy value of 32.16 kJ mol-1 described the influence of temperature on the diffusion coefficient.  Seven thin-layer drying models were fitted to the experimental data.  Among all the drying models, the Midilli–Kucuk model was found to give better prediction than the others.   Keywords: activation energy, effective diffusivity, foam-mat drying, foam characteristics, modeling, Shrim

Study the Possibility of Physical Assessment and Grading of Mazafati Dates Using Digital Image Processing and Support Vector Machines

The traditional methods of grading dates, due to the lack of specific characteristics, have led to incorrect grading and wasting both time and money. Date grading based on the classification algorithms could reduce seller and buyer disagreement. It also allows the product to be sold at the right price. In this research, identification of some qualitative characteristics of Mazafati dates and its classification into four categories (grades 1, 2, 3, and 4) has been done according to the opinions extracted from experts  Intending to define a significant link between the quality of dates, mobile image processing application conducted in in Matlab, support vector machine (SVM) was The results of linear, quadratic, cubic, and medium Gaussian SVMs were 100% accurate, meaning that the classification had been  successful. The ROC curve provided a positive classification rate versus a false positive rate for selecting classification training. A grade 1 positive rate of 0.97 indicates that the current classifier allocates 0.97 of the observations correctly to the positive class (primarily rank). In order to make the final verification, the Kappa coefficient was used. All Kappa values are greater than 0.6 and have sufficient stability. Also, the highest Kappa coefficient was related to the cubic method by more than 0.8 and the lowest one was related to fine Gaussian with a value of 0.76. Due to the accuracy and precision of implementation with SVM, this method with high efficiency wascapable of grading dates

Encapsulated Limonene based Multi-layer Electrostatic Adsorption and Evaluate Its Release under Simulated Oral Conditions

Article in persian with english abstract.International audienceIntroduction Efforts have always been made to protect valuable compounds of medicine, food and aromatics materials that are highly sensitive to environmental conditions by the encapsulation method. encapsulation of flavors, in addition to its protection, allows the aromatic substance to be released in a long time, and the time and place of its release can be controlled. To design these protection systems requires detailed information on encapsulation and release methods, the nature of walls and aromatic materials (Gunning et al.,1999). For encapsulation of sensitive compounds such as lipophilic materials, it is necessary to produce an emulsion of the desired substance in wall materials such as proteins, polysaccharides or a mixture of them. The important factors in encapsulation are the molecular weight, chemical properties and polarity of the core materials, the properties of the materials of the walls, and finally, the methods used to produce microcapsules. (Jafari et al., 2008). The aim of this study was to produce and evaluate the properties of two and six layer multilayer microcapsules containing limonene using soy protein isolate and starch modified by spray drying. The release of encapsulated limonene was investigated under artificial oral conditions under different stress conditions. The results of this study can be used to predict the release rate of the encapsulated flavors and their release conditions. Materials and Methods Solution preparation: The solution of SPI (0-3%) was prepared by methods of Huang et al. (2012). The OSA starch stock solution (0-2%) was prepared by methods of Nilsson and Bergens (2007). Emulsion’s preparation: the primary emulsion of the optimum SPI and secondary emulsion of optimum OSA starch concentration prepared by the method of Noshad et al (2015). Microcapsule production: To prepare the Microcapsules, a laboratory spray dryer was used. 180±5 ᵒC, inlet air temperature, 25 (ml/min) feed rate, and 90±10 ᵒC outlet air temperature were used. Six layer microcapsules was also prepared in the same conditions (Ansarifar et al., 2017) The micro structure, morphology and release of limonene were evaluated and finally by Zero order, First order, Higuchi, and Korsemeyer-peppas models were used to the fitting of experimental data. Limonene release: To investigate the release of the encapsulated limonene, the release of these microcapsules (two and six layer) at 37 ° C and pH = 6.8, as well as frequent chewing (0, 50 and 100 rpm) were examined. For the apply of shear stress, an oral simulator was designed and developed by the Department of Food Science and Technology of Ferdowsi University of Mashhad was used. Results and Discusion The results of particle size changes of the initial emulsion formed with different levels of soy protein isolate showed that the particle size decreased with increasing the concentration of this protein to 1.5% and then it was increased. The results of zeta potential showed that with increasing the concentration of soy protein isolate to 1.5%, the zeta potential of the samples increased and with more than 1.5%, it did not have much effect on the zeta potential of the samples, which indicates that concentrate of 1.5% soy protein isolate has a good ability to cover surface of limonene particles. Similarly, 1.2% of OSA starch was determined for the secondary layer. SEM images of the microcapsules showed that in the two-layer wall microcapsules have cavities, cracks and shrinkage. In the starting of drying, the rate of moisture lost is high and on the other hand, the wall is not strong enough to withstand the stresses caused by the exit of moisture from the walls, so the microcapsule has cavities. In six-layer microcapsules, a smooth, non-cracked surface was observed, which can be attributed to the wall strength due to the increase in the number of layers. Fourier transform infrared spectroscopic (FTIR) test showed that the outer surface of the microcapsules was covered by OSA starch in two and six layer microcapsules. The release profile of encapsulated lim nene showed that the release rate in two layer samples was faster than six layer samples. Also, with increasing shear rate, the amount of release increased. The results of experimental models fitting showed that the first-order model had the best description for releasing limonene from two-and six-layer samples in different conditions. Calculation of diffusion coefficient showed that six-layer microcapsules have a lower diffusion coefficient than two-layer microcapsules, which leads to a decrease in the release rate of limonene. Conclusion The results of this study showed that the layer-by-layer method could be used to produce limonene microcapsules. Soy protein isolate and modified starch can cover limonene droplets well. SEM images showed that the structure of six-layer microcapsules is free of cracks and cavities and has a more uniform surface than two-layer microcapsules. To investigate the mechanism of limonene release from two-and six-layer microcapsules, different kinetic models were used to fit the experimental release data. The results showed that the release of these microcapsules occurred based on the diffusion mechanism and Fick's law, which is the main mechanism of mass transfer in the release process. Also, the results showed that the six-layer microcapsules had a lower diffusion coefficient than the two-layer microcapsules and the release rate was lower in the two-layer microcapsule; This is due to the repetitive coating of soy protein isolate and modified starch around the microcapsules and the increase in wall thickness

Pomegranate seed clustering by machine vision

Application of new procedures for reliable and fast recognition and classification of seeds in the agricultural industry is very important. Recent advances in computer image analysis made applicable the approach of automated quantitative analysis in order to group cultivars according to minor differences in seed traits that would be indiscernible in ocular inspection. In this work, in order to cluster 20 cultivars of pomegranate seed, nine image features and 21 physicochemical properties of them were extracted. The aim of this study was to evaluate if the information extracted from image of pomegranate seeds could be used instead of time‐consuming and partly expensive experiments of measuring their physicochemical properties. After data reduction with principal component analysis (PCA), different kinds of overlapping between these two types of data were controlled. The results showed that clustering base on all variables of image features contain more similar cultivars with clustering base on physicochemical properties (66.67% for cluster 1, 75% for cluster 2, and 50% for cluster 3). Therefore, by applying image analysis technique, the seeds almost were placed in different pomegranate clusters without spending time and additional costs

Effects of coating formulation on structural changes of turkey nugget during frying: MRI evaluation

Application of nondestructive techniques combined with image processing techniques has been increasing in investigating the internal structure of food products. Magnetic resonance imaging (MRI) is one of these methods. The aim of this research is to investigate the effect of coating formulation on structural properties of turkey nugget samples (turkey nugget with typical batter, tragacanth-containing batter and tragacanth) by MRI. Results revealed that the changes caused by the batter formulation could also be examined using the tomographic images. The results also indicated that the brightness of the MRI images of the nugget core and crust decreased during frying. The core of the nugget with the tragacanth-containing batter was brighter revealing its higher moisture content. Furthermore, the nugget core was less reduced in this sample compared with the other ones. This research aimed to present a valuable knowledge about nugget frying pertaining to quality evaluation

Formation of alginate/ Alyssum homolocarpum seed gum (AHSG) microgels through electrospraying technique to encapsulate and release curcumin

This study aimed to produce microgels by electrospraying of alginate/AHSG (Alyssum homolocarpum seed gum) dispersions at different mixing ratios (1:0, 3:1, 1:1) for encapsulation of curcumin. Addition of AHSG to alginate increased the ζ-potential while it reduced the viscosity of the dispersions. Increased alginate to AHSG ratio resulted in smaller microgels and more uniform morphology. Results confirmed that curcumin was physically entrapped within the microgels matrix. As the alginate to AHSG ratio decreased, the microgel's encapsulation efficiency and thermal stability (∆H) increased from 87.76 to 95.85 % and 23.84 to 40.33 (J/g), respectivly. The lowest curcumin release rate during storage was for 3:1 alginate:AHSG microgel (41.4 %). The microgels provided more protection for curcumin against UV irradiation. The release profiles of curcumin from microgels during in vitro digestion were controlled by the Fickian diffusion phenomenon. Overall, these results indicated that electrosprayed alginate/AHSG microgels enhanced the photostability and improved the controlled release of curcumin throughout the gastrointestinal tract

Effect of the milk fat content and starter culture selection on proteolysis and antioxidant activity of probiotic yogurt

In this study, the effects of milk fat content (0%, 2% and 3.5%) and starter culture (autochthonous or commercial) on physicochemical properties, degree of proteolysis, antioxidant activity and viability of Lactobacillus acidophilus, within 21 days storage of probiotic yogurt at 5 ± 1 °C were investigated. Statistical analysis showed that the type of starter culture had a significant effect (P < 0.05) on proteolysis and antioxidant activity, in such a way that both of them were increased until the 14th day of storage but they decreased after this period. Similarly, the pH value of all samples decreased during storage time. It ranged from 3.84-4.34 and 4.18–4.43 for yogurt samples made by autochthonous and commercial starter culture, respectively. According to the results, the survival of Lactobacillus acidophilus decreased during storage time (P < 0.05), although it stood at recommended levels for health effects (at least 106 cfu/ml in traditional yogurt). Milk fat content did not have significant effect on the survival of probiotic organisms (P < 0/05)

Effect of taste and aroma on texture perception in model gels: instrumental and sensory combined approaches

International audienceThe effect of taste and aroma on texture perception was explored in model gels. The samples were composed of two types of gels (gelatin and kappa carrageenan), one aroma (limonene 0 and 0.2% w/v), and one tastant (sucrose 0 and 10% w/v). Twenty-two panelists evaluated three oral texture attributes (hardness, fragmentation, and melting), while the uniaxial compression test characterized the instrumental texture parameters (Young’s modulus and positive peak force). The results of texture perception showed that gelatin was perceived as harder than kappa carrageenan. Sucrose reduced hardness perception in kappa carrageenan while it increased it in gelatin. Sucrose increased melting perception but did not change the hardness and fragmentation perception in kappa carrageenan. Fragmentation perception was not changed by addition of sugar or limonene. Gelatin had a higher positive peak force than the kappa carrageenan, but Young's modulus in kappa carrageenan was higher than gelatin. Some sensory results were explained by matrix interactions. However, some sensory texture results were not explained by the instrumental parameters which gives the possibility of a cognitive relationship in taste–texture interaction

Chitosan-limonene coating in combination with modified atmosphere packaging preserve postharvest quality of cucumber during storage

Since cucumbers suffer from a short postharvest life, applying different technologies is increasingly used as effective ways to increase their shelf life and quality. In this study a combination of chitosan-limonene coating and MAP storage has been used as a postharvest treatment to maintain cucumber quality. Samples were stored in three different packages: A (21% O2, macro-perforated package to be in equilibrium with air); package B (active MAP, starting concentrations 10% O2 + 5% CO2); package C (passive MAP starting concentrations 21% O2 + 0.1% CO2); they were stored at three temperatures (20, 10, and 4 °C). Quality parameters of cucumber such as weight loss, firmness, color, pH, fungal growth, Tg, organoleptic properties were determined. Interactive effects of coating, package, temperature, and storage time showed that coating and MAP in general had positive effects on several quality aspects. Coating combined with active MAP had the most positive effect on most postharvest attributes. However, using active MAP at higher temperature led to quality problems and is only useful if storage time is short. The combined usage of active MAP and chitosan-based coating on cucumber represents an innovative and interesting method for commercial application