Food Engineering
Setereh Ramezani; Mohammad Shahedi; Milad Fathi
Abstract
Global concern about human health and the increase the prevalence of chronic diseases in recent years lead to growing appeals for nutritious and healthy compounds, such as coenzyme Q10. Susceptibility to heat and lipophilic properties of coenzyme Q10 limit its utilization in food. Encapsulation is a ...
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Global concern about human health and the increase the prevalence of chronic diseases in recent years lead to growing appeals for nutritious and healthy compounds, such as coenzyme Q10. Susceptibility to heat and lipophilic properties of coenzyme Q10 limit its utilization in food. Encapsulation is a technology that protects bioactive ingredients from harsh environmental conditions and extends shelf life. The purpose of this study was to encapsulate coenzyme Q10 using complex coacervation by gelatin–basil seed mucilage and characterize physical, thermal and chemical properties of produced microcapsules. Response surface methodology was applied to determine the optimum level of the four formulation variables for maximum encapsulation efficiency, loading capacity and turbidity and minimum supernatant absorption. The optimum microcapsules had encapsulation efficiency of 83.69%, encapsulation load of 16.32%, turbidity of 0.979 and supernatant absorption of 0.227. The microcapsules were assessed by scanning electron microscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The results of FTIR confirmed the formation of coacervates. The thermogram of Q10 loaded microcapsule melting point was not observed at its melting point (50°C) due to its solubility in the oil phase and appropriate entrapment. Release behavior of Q10 was studied by different mathematical models. Microencapsulated Q10 was used to fortify milk and the results showed that the developed protein-carbohydrate microcapsules can be applied for protection of hydrophobic compounds.
Food Engineering
Behnaz Vafania; Milad Fathi; Sabiheh Soleimanian Zad
Abstract
The aim of this research was to investigate the efficiency of nozzle-less electrospinning for encapsulation of ajwain essential oil (as a hydrophobic bioactive) using two hydrocolloids (chitosan/gelatin) in order to enhance its antioxidant properties and stability for food applications. Nanofibers were ...
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The aim of this research was to investigate the efficiency of nozzle-less electrospinning for encapsulation of ajwain essential oil (as a hydrophobic bioactive) using two hydrocolloids (chitosan/gelatin) in order to enhance its antioxidant properties and stability for food applications. Nanofibers were spun using chitosan/gelatin in ratios of 1:6, 1:8 and 1:10 and ajwain concentrations of 20 and 40%. Solution properties (i.e. viscosity and electrical conductivity) were measured. Encapsulation efficiency and loading capacity data illustrated an enhancement with increasing of essential oil concentration. Fibers diameter and morphology were studied by scanning electron microscopy (SEM). The chitosan/gelatin nanofibers with ratio of 1:6 containing 40% essential oil had the highest encapsulation efficiency (99.9%), loading capacity (39.9%) and the smallest diameter (146 nm). Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) proved that during electrospinning, no any chemical interaction was occurred between ingredients and differential scanning calorimetry (DSC) data showed that essential oil was well encapsulated in nanofibers. Antioxidant properties were analyzed by 2,2-diphenyl-1-picrylhydrazylradical and approved the efficiency of encapsulation for protection of antioxidants.
Marzieh Mirzaaghaei; Amir Hossein Goli; Milad Fathi
Abstract
Introduction: Flavor, taste, odor and color of fresh apple juice is unstable during concentration process and storage. Pectic substances and phenolic compounds are responsible for these physicochemical changes. So, decreasing of these compounds is necessary to improve the appearance and marketability ...
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Introduction: Flavor, taste, odor and color of fresh apple juice is unstable during concentration process and storage. Pectic substances and phenolic compounds are responsible for these physicochemical changes. So, decreasing of these compounds is necessary to improve the appearance and marketability of apple juice. In fruit juice industry, clarification is one of the most important steps which removes pectin, polyphenols and other unfavorable components and prevents haze formation during storage. Enzymatic clarification (depectinization) can be applied for removal of pectic substances by using pectinase. This enzyme can hydrolyze pectin and produce pectin-protein complexes which would be settled easily. Also in depectinization step, some enzymes such as amylase and amyloglucosidase can be used to degrade starch. Fining agents such as gelatin, bentonite, activated carbon, silicasol or a combination of these compounds can be used in conventional clarification. Sepiolite is a natural fibrous phyllasillicate clay mineral with a formula Mg8Si12O30(OH)4(OH2)4. nH2O(n=6-8) which has specific physicochemical properties such as high porosity, surface area and adsorption capacity. This clay clay has been used in several important applications such as decolorization of sugar juice, removal of phosphorus from vegetable oil and enhancing decoloration of crude palm oil. In this research, efficiency of Sepiolite for apple juice clarification was evaluated. First, the response surface methodology (RSM) was used to optimize apple juice clarification conditions. Then, a comparison among Sepiolite and other commercial fining agents in respect to clarification efficiency was accomplished. Finally, three types of zero-, first- and second-order kinetic models were used for explanation of changes in turbidity, color, viscosity and total phenolic content (TPC) during clarification process of apple juice.
Materials and Methods: The pasteurized and unclarified apple juice, Bentonite, Gelatin (Bloom= 80-100), Amylase (Alphamyl MG) and Pectinase (Pectofruit XL) were gratefully obtained from Behnoosh Iran Co. (Shahrekord, Iran). Sepiolite (with specific surface area of 105 m2/g) was purchased from Farapooyan Isatis Yazd Co. (Yazd, Iran). The kieselgel and chemicals with analytical grade were purchased from Merck Co. (Germany). Sepiolite was activated with hydrochloric acid according to Balci’s method with slight modification. For evaluation of Sepiolite changes, some analysis like pH, acidity, density and the moisture content of Sepiolite clay were done before and after the activation by the method of Sabah and Çelik. Specific surface area was measured by using the BET method (Belsorp mini II, Japan). XRF method (PW148, Philips Co.) was used for determining of difference between Sepiolite elemental compositions before and after the activation. A pretreatment was conducted to improve the performance of fining agents according to Türkyilmaz et al.’s method with slight modification. The swelling capability of fining agents in water increases their clarification capacity. In the method of RSM, the independent factors at three levels were concentration of activated Sepiolite (0.05-0.1% w/v), temperature of clarification (50-60˚C) and process time (2-10 h). Juice turbidity was regarded as response. As the first step in clarification of apple juice, amylase and pectinase enzymes were applied (25 µl of each enzyme per 100 mL juice at 20˚C). The mixture was stirred and heated in an incubator at 55˚C for 1 h. Sepiolite was mixed with juice in certain concentrations, stirred and placed in definite temperature and time according to each run of RSM. Finally, the juice was centrifuged (12000 rpm for 5 min) to remove the clay from clarified juice. For kinetic studies, the above steps were done in the optimized conditions using 0.05% fining agents at 50˚C for 7 h. A portable turbidometer (MARTINI, Mi 415, Romania) and the capillary viscometer (Ubbelohde-Viscometer, Fisher, USA) were used for measuring the juice turbidity and viscosity at 20˚C and expressed as NTU (Nephelometeric Turbidity Unit) and centipoise (cp), respectively. Color was measured at 20˚C by using a color meter (ZE 6000, Nippon DENSHOKU). The parameters which used for color expression were L* and a* parameters based on CIE Lab system. The Folin-Ciocalteu reagent was used for measuring the total phenolic content of juice and expressed as mg gallic acid equivalent per 100 mL juice. To evaluate Sepiolite performance in juice clarification, following fining agents were applied at optimal conditions: sepiolite (S), commercial bentonite (B), and combination of these agents with gelatin (G) and kieselgel (K) (S+G, B+G, S+G+K, B+G+K). The used concentrations of bentonite, gelatin and kieselgel were 0.05%, 0.015% and 0.04% (w/v), respectively. Sampling was conducted at 1 h intervals to evaluate the changes in juice turbidity, viscosity, color and TPC during clarification process. The rates of changes were determined by three types of zero-, first- and second-order kinetic models.
Results and Discussion: Results showed that the activated Sepiolite had less amounts of weight loss, density and pH than the native sample. On the other hand, moisture content and acidity increased. Also, acid activated Sepiolite had higher amounts of SiO2 groups. The second-order polynomial (quadratic) model was suggested as the best for describing the optimum conditions of clarification with insignificant lack of fit and high R2 (0.9845). Based on the results, process time had a significant (p
Milad Fathi; Seyed Mohammad Ali Razavi
Abstract
In this study, potential application of image texture analysis as a non-destructive method for automation and prediction of mechanical properties of carrot chips was investigated. Samples were fried at different processing conditions and moisture content, colour parameters (i.e. L*, a*, b* and E) ...
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In this study, potential application of image texture analysis as a non-destructive method for automation and prediction of mechanical properties of carrot chips was investigated. Samples were fried at different processing conditions and moisture content, colour parameters (i.e. L*, a*, b* and E) and mechanical properties (i.e. hardness and apparent modulus) were determined. Hardness and apparent modulus increased by increasing frying temperature and time. Four image texture features namely contrast, correlation, energy and homogeneity were calculated using gray level co-occurrence matrix. The results showed contrast and energy of gray level images were well correlated with hardness of fried samples in compression and puncture tests. Correlation coefficients of 0.97 and 0.98 between four image texture features and hardness were obtained in compression and puncture tests, respectively. Results indicate that image texture analysis can be successfully applied as a non-destructive method for estimation of mechanical properties of carrot.
Zeynab FarhaniNejad; Milad Fathi; Mohammad Shahedi
Abstract
Introduction: Banana is one of the most popular tropical fruits in all over the world with notable post-harvest losses. Due to its high moisture content preventing long preservation period. So, it needs a proper preservation method to prevent product lost especially in main produceing countries. Since ...
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Introduction: Banana is one of the most popular tropical fruits in all over the world with notable post-harvest losses. Due to its high moisture content preventing long preservation period. So, it needs a proper preservation method to prevent product lost especially in main produceing countries. Since banana is an un-freezable fruit, thermal processing such as drying or canning could be more appropriate for prolonging its shelf life. On the other hand, high energy consumption and being cost intensive are two most important disadvantages of thermal processing. In order to decrease the side effects of thermal process on quality parameters, pretreatment of samples could be applied to reduce time of main process.Osmotic dehydration is a non-thermal pretreatment which provides partial removal of water by immersing sample in an osmotic solution.But this process also takes a long immersion time to enough reduction of moisture. So this leads to undesirable effect on texture and colors.This study was performed to eliminate some side effects of osmotic dehydration on quality and finally introduce an optimized condition resulting best performance of process.A novel all-knowing method for optimization of process is genetic algorithm (GA) which is a search heuristic that mimics process of natural selection. It generates solutions for the optimization of problems using techniques inspired by natural evolution, such as inheritance, mutation, selection, and crossover. In this research, genetic algorithm was applied to predict optimum condition of osmotic dehydration.Material and methods: Osmotic dehydration was performed using aqueous solution of sucrose in concentration of 45% (w/w) for immersion time of 3 hr. The first challenge was improving mechanical properties of banana slices by adding calcium lactate to sucrose solution in concentrationsof 0, 2, 3 and 4%.For the next step in order to protect samples from enzymatic browning mixture of ascorbic acid (0.25 %) and citric acid (0, 0.5, 1, and 1.5%) were used.The pH of solution was measured for each level of adding citric acids. The efficiency of operation was estimated by computingwater loss and solid gain. Firmness of dehydrated samples wasmeasured using a texture analyzer (INSTRON, 1140, Singapore) and penetration test. Image acquisition technique was applied to measure L*, a* and b* indices.The coefficient of efficiency was defined as the ratio of water loss to solid gain and calculated to estimate performance of treatment in new condition. Finally, optimized conditionsfor maintaining the lowest solid gain and color changes, the highest water loss and firmness waterlosswere predicted by genetic algorithms method. The accuracy of model was investigated using statistical parameters such as mean absolute error (AME), normalized mean square error (NMSE),mean square error (MSE).Results and discussion: The results of experiments showed a significant increase of firmness by adding lactate calcium. This observation was due to complex formation between calcium and cell wall ingredients. Thesecomplexes have a decreasing effect on solid gain.Because complexes preventedmacromoleculesentering such as sucrose to the cells.On the other hand,calcium lactate and citric acid had interaction on mentioned parameters.Firmness showed less firmness when citric acid was added to the solution. Because citric acid as a chelating agents can blockdivalent cations and prevent from effective reaction with plant cells.Also citric acid can disconnect methoxyl groups from protopectinproducing softer texture.However, treated samples still showed firmer texture than control sample. It could be due to the additional effect of citric acid which makes carboxyl groups available for divalent calcium cations during conversion of protopectin to the pectin.For color parameters,only use of citric acid could not decrease the total change of color because yellow index increased due to the hydration of citric acids. But for the use of two factors, a significant decrease of total change of color was observed.For water loss, increase of solvents in each treatment led to raise of water loss due to the increase of osmotic pressure.In this circumstance determination of suitable concentration for each factorresulting best performance is complex, so it is necessary to apply a system canpredict optimized conditions. Genetic algorithms estimated optimum condition formaximum firmness and water loss, minimum solid gain and total change of color.In this condition the concentrations of lactate calcium and citric acid were %3.99 and %0.86, respectively. Also predicted values for water loss, solid gain, firmness and total change of color were earned %18.01, %5.07, 1.47 N and 11.37.MAE, NMSE and AME parameters (2.062, 0.021, and 1.099 respectively) were used for investigation of difference between estimated and experimental data which showed high efficiency of genetic algorithm for optimization of osmotic dehydration of banana.Investigating the efficiency ofcoefficient of treatments showed that application of both factors (calcium lactate and citric acid) significantly had more efficiency in comparison to the control samples regarding quality factors.
Fakhri Shahidi; Mohebbat Mohebbi; Mohammad Noshad; Ahmad Ehtiati; Milad Fathi
Abstract
Banana is one of the most important tropical fruit from commercial and industrial point of view. This fruit is an extremely perishable fruit which can not be preserved using freezing process. Therefore, drying is the most promising method. Conventional air drying is energy intensive and consequently ...
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Banana is one of the most important tropical fruit from commercial and industrial point of view. This fruit is an extremely perishable fruit which can not be preserved using freezing process. Therefore, drying is the most promising method. Conventional air drying is energy intensive and consequently expensive method. Pre-treatments can be used to reduce the initial water content or to modify the fruit tissue which will result in higher yield with lower costs. In this research, the effect of osmotic dehydration and ultrasonic pre-treatment variables prior to air drying of bananas, including the type of solution (Glucose, Sucrose), time of immersion in osmotic solution (30, 45, 60 min), solution concentration (Brix 30 and 50), ultrasonication time (10, 20, 30 min) on water loss, solid gain, shrinkage, effective diffusivities and color in the process were studied. Results showed that the highest rate of water loss and solid gain and also the lowest rate of shrinkage were obtained in both pre-treatments when 50% glucose concentration was applied. The results indicated that unlike ultrasonication, osmotic pretreatment had a significant effect on color parameters of dried bananas.
Keywords: Banana, Drying, Image processing, Osmotic dehydration, Qualitative characteristics, Ultrasound
Safie Khalilian; Mohebbat Mohebbi; Milad Fathi
Abstract
In this research, the possibility of production of a new nutrient fruit-based product prepared by applying apple puree, pectin, gelatin, starch, sugar and other ingredients has been investigated. Totally 10 different apple pastille formulations were produced. Water activity and sensory attributes of ...
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In this research, the possibility of production of a new nutrient fruit-based product prepared by applying apple puree, pectin, gelatin, starch, sugar and other ingredients has been investigated. Totally 10 different apple pastille formulations were produced. Water activity and sensory attributes of the samples were evaluated. Means were compared at significance level of 5%by Duncan test. The regression relationships were calculated. The results indicated that independent variables (starch, gelatin and sweeteners) have significant effects on dependent variables (water activity and sensory parameters). The sample containing 1.5% gelatin, 7.5%liquid glucose and 7.5% sucrose with optimal water activity of semi-dried products had the highest acceptance and been chosen as the best formula which could be produced in large scale.
Keywords: Apple, Fruit pastille, Sensory evaluation, Water activity
