Mitra Mansouri Bani; Vahid Samavati; Marzieh Bolandi
Abstract
Introduction: The Cholesterol in our diet is a risk factor for the prevalence of cardiovascular diseases. One of the effective ways to reduce the incidence of such diseases is to remove cholesterol, including animal fats, from our food sources. In this research, attempts were made to investigate the ...
Read More
Introduction: The Cholesterol in our diet is a risk factor for the prevalence of cardiovascular diseases. One of the effective ways to reduce the incidence of such diseases is to remove cholesterol, including animal fats, from our food sources. In this research, attempts were made to investigate the effect of operational factors on reducing cholesterol in cream by beta-cyclodextrin using RSM and to examine its physicochemical properties. The variables in this study were beta-cyclodextrin concentration, mixing temperature and mixing time. Materials and Methods: The 3.5% fat raw milk was pasteurized at 72°C for 16 s, and then it was cooled to 55°C. The milk cream was separated by a separator and adjusted to 36% fat. Beta-cyclodextrin was added in 0.5, 1, 1.5% concentration in water bath at three levels of 10, 30, 50 ° C. It was mixed at three time intervals of 5, 15, 25, min. Cream containing beta-cyclodextrin was centrifuged to eliminate the complex formed in different periods and the beta-cyclodextrin and cholesterol complex was isolated. Beta-cyclodextrin of 99.2% purity was purchased from Sigma-Aldrich and all chemical agents from Merk, Germany. To measure cholesterol content in the preparation phase, hexane and ethanolic solution of potassium hydroxide (Merk) and the standard solution of cholesterol (Merk) were used. To determine the level of cholesterol in the samples, Lee et al. (1999) method was used after a few modifications. Firstly, cholesterol was extracted from the specimens and the cholesterol levels in the samples were determined with a chromatography apparatus equipped with flame ionization. The quantitative measurement of cholesterol was conducted by comparing the peak areas with a response from the internal standard. The experiments were designed, using the response surface method and the Box-Behnken Design (BBD), to achieve a high-efficiency process in reducing the highest cholesterol level and determining optimum conditions. The viscosity was determined using a Brookfield viscometer, and the over run and foam stability of the cholesterol cream samples were determined using a Graduated cylinder. Results and discussion: Due to the cavity in the central part of beta-cyclodextrin molecular arrangement, it can form a stable cholesterol-insoluble complex and help to isolate it from the product. The results showed that time, mixing temperature, and beta-cyclodextrin concentration all had a positive effect on reducing the level of cholesterol, and the effect of independent factors was almost the same, as the time factor had the highest effect, supported in Makoto et al. (1999). Concentration factor had the least effect on cholesterol reduction, contrary to studies by Aryafar et al. (2007) and Yen et al. (1995). Among the interactions of the investigated factors, the highest effect was due to the simultaneous effects of temperature and time (88.9%) and the least effect was due to the simultaneous effect of concentration and temperature (85.5%). Findings of this study showed that the use of beta-cyclodextrin resulted in a successful reduction of cholesterol from the product without affecting tissue properties, increasing viscosity and volume, or reducing stability of the foam. The absorption of cholesterol by beta-cyclosporine depends on its concentration. The mixing time and temperature also boosts the effect. After examining the effects of each independent variable, it can be concluded that all three investigated variables have an incremental effect on the level of cholesterol in the evaluated levels. Increasing mixing time has the highest effect on increasing cholesterol and increasing the concentration of beta-cyclodextrin has the lowest effect on cholesterol reduction. Investigating the interaction effects of variables also showed that the simultaneous effect of temperature and time with the proper concentration of beta-cyclodextrin could have a significant effect on cholesterol reduction. The response surface method and Box-Behnken Design as statistical optimization and modeling techniques enabled the researchers to predict the optimal conditions for maximal removal of cholesterol by beta-cyclodextrin at the decided levels. The optimal operating condition obtained by the model for 36% fat cream contains 42.1% beta-cyclodextrin concentration, 76.75 ° C temperature and 87.83 min of mixing time. The predicted cholesterol reduction in these conditions was 89.92%, which was very close to the experimental value obtained in predicted optimal conditions. It indicates the accuracy and predictive power of the intended model.
Vahid Alizadeh; Hassan Barzegar; Behzad Nasehi; Vahid Samavati
Abstract
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 ...
Read More
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.
Mehran Nouri; Behzad Nasehi; Vahid Samavati; Saman Abdanan
Abstract
Introduction: Fried foods such as donuts enjoyed worldwide for their taste, distinctive flavor, aroma and crunchy texture. There is, however, grave health concern over large fat content of fried foods (Melito and Farkas, 2013). There are several ways to lower fat content in deep-fried foods. One method ...
Read More
Introduction: Fried foods such as donuts enjoyed worldwide for their taste, distinctive flavor, aroma and crunchy texture. There is, however, grave health concern over large fat content of fried foods (Melito and Farkas, 2013). There are several ways to lower fat content in deep-fried foods. One method is to reformulate the product by adding hydrophilic ingredients such as dietary fibers to reduce oil uptake during frying. Another method to reduce fat content is to partially cook the food using another heating method (Melito and Farkas, 2012). There is an increasing interest in microwaving foods for several reasons: it is faster than conventional methods, the energy consumption is often lower and foods cooked by microwaving maintain nutritional integrity.vIn foods, the appearance is a main criterion in making purchasing decisions. Appearance is used throughout the production –storage-marketing-utilization chain as the key means of judging the quality of individual units of product. The appearance of unities of products could be assessed by considering their color and surface texture. The use of computer-vision technology has quickly increased in the fields of quality inspection, classification and evaluation in processing a large number of food products (Brosnan and Sun, 2004). Therefore the aim of this study was to study the effects of microwave pre-treatment on sensory and appearance properties of donut.
Materials and methods: Response surface methodology and Box- Behnken design were applied to evaluate the effects of independent variable include microwave power (300-900 W), microwave time (30-90 s) and frying time (70-130 s) on sensory and appearance properties of donuts. Donuts were prepared according to the formulation by Melito and Farkas (2012) with some modifications. Ingredients used in donuts formulation were consisted of 100 g of wheat flour (9 g/100g), 52 g of water, 9.75 g of Shortening, 14 g of Egg, 14 g of water for yeast, 6.80 g of sugar, 6.80 g of nonfat dried milk powder, 3.25 g of active dried yeast, 1.70 g of Vanilla extract, 1.7 g of baking powder, 1.70 g of Salt, 1.3 g of Persian gum and 7.00 g of carrot pomace powder. The dough was cut into squares approximately 50 mm on each side. Then, the dough pieces were allowed to proof for 30 min at 27 ºC. The proofed samples were pre-treated using a microwave oven at different levels of microwave power and microwave time in accordance with the experimental design. Formerly, the per-treated donuts were deep-fat fried in a Moulinex deep-fat fryer (model F18-RA, France) filled with 1.5 L of vegetable frying oil (A mixture of Sunflower, palm, and soybean oil; Behshahr CO., Tehran, Iran) at different levels of frying time in accordance with the experimental design. The oil was preheated for 30 min prior to frying and replaced with fresh oil after every frying process. After frying, donuts were removed from the fryer and allowed to cool for 30 min on paper towels. They were then stored in coded sealed polyethylene bags.The evaluation of the crumb grain and crust color of donuts was performed using an image analysis system consisted of a Canon digital camera (model SX60 HS, Japan) and a personal computer with a Pentium(R) Dual-Core processor and Windows 7 Ultimate. The samples were photographed at a fixed distance of 30 cm from the crumb of samples, which were sitting inside a black box. The captured images were analyzed using the MATLAB R2014a software (The MathWorks Inc., Natick, Mass, USA).The CIE L*a*b* (or CIELAB) color model was used for determination of the crust color of donuts. Crumb grain features of the donut samples were obtained with described digital image analysis system. After imaging, each image was converted from RGB format to 8 bits (grey level) using the MATLAB software. In this format, an area of 3 × 3 cm2 was selected at the center of the captured image. After contrast enhancement of image, the image segmented using the Otsu algorithm, which produces highly uniform binary images (Otsu, 1979). Finally, crumb grain properties of donuts were studied by determination of cells densities and area of cells. Sensory evaluation of donut samples was carried out by assigning scores for crust appearance, crumb appearance, crust color, aroma, texture, taste and overall acceptance parameters based on a nine-point hedonic scale. (Stone et al., 2012).
Results and discussion: Results showed that roughness of the donuts surface increased significantly (p
Vahid Alizade; Hassan Barzegar; Behzad Nasehi; Vahid Samavati
Abstract
Introduction: The environmental effect of synthetic plastic wastes is of increasing global concern. There is an urgent need to develop and apply renewable biopolymer materials. Development of edible and biodegradable films can help solving the waste disposal problem by partially replacing synthetic plastics ...
Read More
Introduction: The environmental effect of synthetic plastic wastes is of increasing global concern. There is an urgent need to develop and apply renewable biopolymer materials. Development of edible and biodegradable films can help solving the waste disposal problem by partially replacing synthetic plastics (Martins et al., 2012). Chitosan; a linear polysaccharide composed of (1, 4)-linked 2-amino-deoxy-b-d-glucan, is a deacetylated (to varying degrees) product of chitin, which is the second most abundant polymer found in nature after cellulose. It has been proved to be biodegradable, biofunctional, biocompatible, nontoxic and have strong antifungal and antimicrobial properties (Aider, 2010). Thus, this work was undertaken to investigate the physical, optical, barrier, mechanical, microstructural, and antimicrobial properties of chitosan films incorporated with PEO, to examine its potential applications as a packaging material.
Materials & method: The films were prepared according to the solvent casting technique reported by (Abdollahi et al., 2012) with some modifications. Tensile strenght (TS) and elongation at break (E) of the films were measured with texture analyzer according to Barzegar et al. (2014) method. Equilibrated film strips (at 53% RH for 48 h) were fixed between the grips with an initial separation of 50 mm and the cross-head speed was set at 50 mm/min. TS was calculated by dividing the maximum force by the initial area of the film and E% was calculated through dividing the extension at the moment of specimen rupture by the initial gauge length and multiplying by 100. The WVP of the films was determined at according to the Shojaee-Aliabadi et al. (2013). The test cups containing anhydrous calcium chloride (0% RH) were sealed by the test films, then were placed inside a desiccator containing sodium-chloride-saturated solution (75% RH). Weight gain of the cups along time were recorded periodically and plotted as a function of time. Antimicrobial properties of the films were assessed using the disc-diffusion method according to Dashipour et al. (2015). Four gram-positive or gram-negative bacteria, including B. cereus, S. aureus, E. coli and S. typhimurium were used for testing.
Results and discussions: The influence of PEO incorporation on thickness, TS, EAB, WVP and water solubility of films can be seen in Table 1. The incorporation of PEO into the film-forming dispersion led to an increase in the thickness of the films, which varied between 0.131 mm and 0.185 mm. It could be due to the entrapment of PEO micro droplets by the polymer matrix (Dashipour et al. 2015). By increasing PEO concentration from 0.5 to 2 % in the film solutions, WS decreased markedly from 22.46 to 16.15 (P < 0.05). This behavior can be explained by the cross-linking effects of PEO components to esters and/or amide groups. Cross-linking in the chitosan film leads to a polymer with lower water solubility, which is useful when product integrity and water resistance are intended (Hosseini et al., 2009).
Table 1. Physical and mechanical properties of chitosan films.
PEO (% v/v) Thickness (mm)
Solubility in water (%) WVP
(g s-1 m-1 Pa-1 × 10-10) TS
(MPa) EAB
(%)
0.0 0.131 ± 0.01d 22.46 ± 0.73a 1.04 ± 0.05c 21.22 ± 1.97a 49.05 ± 1.63c
0.5 0.153± 0.01c 21.19 ± 1.22a 1.12 ± 0.06c 20.09 ± 1.40a 50.36 ± 2.98c
1 0.167 ± 0.01b 18.47 ± 0.53b 1.35 ± 0.09b 17.04 ± 1.26b 55.25 ± 2.95b
2 0.185 ± 0.01a 16.15 ± 0.54c 1.73 ± 0.09a 13.23 ± 1.35c 59.37 ± 2.49a
The incorporation of PEO into chitosan-based films leads to an increase in WVP values from 1.04 to 1.73 g s-1 m-1 Pa-1 × 10-10. A similar trend has been found by Bonilla et al., (2011) in chitosan-based films incorporated with thyme essential oil. The structural discontinuities induced in the polymer network by the addition of PEO could be the reason for the lowest resistance to breakage of the emulsified films. These discontinuities greatly reduced the film cohesion and mechanical resistance (Bonilla et al., 2012). Conversely, the EAB value of the films increased significantly (P < 0.05) from 49.05% to 59.37%, because the essential oil acted as a plasticizer even at small concentrations and enhanced the flexibility of the polymer chains.
The effects of PEO on the antimicrobial properties of the chitosan films are shown in Table 2. The films containing 1% PEO showed a certain inhibitory effect against B. cereus and S. aureus but no inhibition against S. typhimurium and E. coli. As the concentration of PEO increased, the zone of inhibition also increased significantly (P < 0.05). The films containing 2% PEO were effective against all studied bacteria and a greater inhibitory power was observed on S. aureus with the zone area of 49.67 mm2. The inhibitory effect of PEO is due to the two monoterpene hydrocarbons, α-pinene, and β-pinene (Barrero et al., 2005).
Table2. Antimicrobial activity of chitosan films.
PEO (% v/v) Inhibition zone (mm2)
S. aureus B. cereus E. coli S. typhimurium
0.0 0.00c 0.00c 0.00b 0.00b
0.5 0.00c 0.00c 0.00b 0.00b
1 22.58 ± 1.76b 15.63 ± 0.63b 0.00b 0.00b
2 49.67 ± 3.02a 41.96 ± 1.40a 21.12 ± 1.87a 12.49 ± 1.57a
Conclusion: The results obtained in this study showed that the chitosan films incorporated with PEO has a good potential to being empolyed as an active film to preserve food products. Addition of PEO decreased water solubility and tensile strength, while increased the thickness, WVP and percent elongation of the films. Overall, this study demonstrates that PEO-containing films present a good potential for their application in the food industry.
Mehran Nouri; Behzad Nasehi; Vahid Samavati; Saman Abdanan
Abstract
Introduction: Increased awareness of diet-health association has led to the growth of health food industry. Deep-fat fried foods such as donuts enjoy wide popularity owing to their taste, distinctive flavor, aroma and crunchy texture. There is, however, a great health concern over large fat content of ...
Read More
Introduction: Increased awareness of diet-health association has led to the growth of health food industry. Deep-fat fried foods such as donuts enjoy wide popularity owing to their taste, distinctive flavor, aroma and crunchy texture. There is, however, a great health concern over large fat content of fried foods. Incorporating the dietary fiber such as hydrocolloids into the food substrate in the batter formulation is one of the most effective strategies to decrease fat uptake in fried foods. Dietary fibers act as water binders in a coating or batter formulation through which reduce fat uptake of fried foods. That is, an increase of water content of food could lead to a decrease of oil penetration during the frying process. Persian gum (PG), as a novel gum, is exudates of the wild or mountain almond trees (the main source is Amygdalus scoparia Spach). Carrot pomace is a fibre-rich by-product of carrot juice industries which contains approximately 80% of carrot carotenes. Carrot juice yield is reported to be only 60-70% and the remaining pomace is usually disposed of as feed or fertilizer. There is an increasing interest in microwaving foods for several reasons: it is faster than conventional methods, the energy consumption is often lower and foods cooked by microwaving maintain nutritional integrity. Therefore, the aim of this study was to examine the effect of microwave pre-treatment on physico-chemical properties of donut containing Persian gum and carrot pomace powder sources of dietary fiber.
Materials and methods: Donuts were prepared according to the formulation reported by Melito and Farkas (2012). Ingredients used in control donut formulation were consisted of 100 g of wheat flour (9 g/100g), 38 g of water, 9g of Shortening, 13g of Egg, 13g of water for yeast, 6.3g of sugar, 6.3g of nonfat dried milk powder, 3g of active dried yeast, 1.6g of Vanilla extract, 1.6g of baking powder, and 1.6g of Salt. For the making of donuts, the flour blends were prepared by replacing wheat flour with 1.2 g/100g PG and 645 g/100g CPP. As well, water was added at 48.16 g/100g based on flour weight. The exudate gums of mountain almond trees were collected in Lorestan province. In order to eliminate foreign matters such as dust and dirt, the PG was washed three times with its threefold weight of ethanol (96% w/v) for 15 min under constant stirring. After removing ethanol by drying in an oven (at 60º C for 6 h) the PG was ground using a coffee grinder (model 320, Spain), sieved (180 µm) and packaged in polyethylene packs and then stored in 4ºC. Fresh carrots were purchased from a local market. Carrots were washed and then pressed with a juice extractor and the resultant pomace was collected. The carrot pomace was blanched in water (80 ± 2°C for 3 min) and then cooled in cold water (4º C). The pomace water was drained with cheese-cloth prior to drying. Finally, the carrot pomace was dried in an oven (60º C for 12 h). The dried pomace was ground using a coffee grinder to fine powder. The carrot pomace powder was sieved (180 µm) and packed in polyethylene packs and then stored in 4ºC. Specific volume of donuts was determined using the rapeseed displacement AACC method. Moisture content of donuts crumb was measured using a oven at 105 ºC for 3. The fat content of dried donuts was determined by Soxhlet extraction with petroleum ether for 5 h. Firmness and springiness were measured in triplicate using a TA.XT2i Texture Analyzer equipped with a 5 kg load cell and a P/35 mm aluminum cylindrical probe. Crumb grain (total number of cells and porosity) and crumb color of donuts were evaluated using an image analysis system consisted of a digital camera, a personal computer and MATLAB R2014a software. The control and optimized donuts were evaluated for acceptance of their appearance, crust color, crumb color, aroma, texture, taste and overall acceptance based on a nine-point hedonic scale. Response Surface Methodology (RSM) and Box-Behnken design with 3 factors were applied to obtain optimal levels of independent variables including microwave power (300-900 W), microwave time (30-90 s) and frying time (70-130 s).
Results and discussion: The results indicatedthat moisture content significantly (p
Erfan Danesh; Hossein Jooyandeh; Vahid Samavati; Mostafa Goudarzi
Abstract
Introduction: Scientific evidence has demonstrated that consumption of high-fat foods has direct connection with increasing incidences of various diseases such as obesity, diabetes, hardening of the artery walls and blood pressure. Thus, demand for low-fat foods has increasingly been promoted by health-conscious ...
Read More
Introduction: Scientific evidence has demonstrated that consumption of high-fat foods has direct connection with increasing incidences of various diseases such as obesity, diabetes, hardening of the artery walls and blood pressure. Thus, demand for low-fat foods has increasingly been promoted by health-conscious consumers. However, development of low-fat foods is challenging as fat makes a major contribution to sensory attributes of many foods. Low-fat cheeses are usually characterized as having a flat taste, more translucency and a rubbery and gummy texture. A common strategy for improving the properties of low-fat cheeses is to increase its moisture content sufficiently to provide moisture to protein ratio which is greater than or equal to its full-fat counterpart. The addition of denatured whey proteins, which are known for their high water-holding capacity, to cheese milk is one method used to achieve this objective. Likewise, transglutaminase treatment of cheeses milk has been shown to increase the moisture content of the resultant cheese. Enzyme transglutaminase (MTGase; protein-glutamine gamma glutamyl transferase, EC 2.3.2.13) catalyzes acyl transfer reactions between protein intra- or inter- chain glutamine (acyl donor) and lysine (acyl acceptor) peptide residues. UF-Feta cheese has the highest per capita consumption amongst cheese varieties in Iran. However, UF-Feta cheese is also perceived as being high in fat, discouraging some consumers from including it in their diets. The objective of this study was enzymatic incorporation of whey proteins into the formulation of UF-Feta cheese by TGase in order to obtain a low-fat product with desirable textural and sensory properties.
Materials and methods: The experiments were designed according to a 5-level-3-factor central composite design using response surface methodology (RSM). The independent variable were formulation ingredients including TGase enzyme (0-2 units/g protein), whey protein concentrate (WPC) (0-16 % w/w) and fat (0-10 % w/w) and the responses of interest were the physicochemical (moisture content and lightness (L*)), textural (hardness, adhesiveness, cohesiveness and springiness) and sensory properties (flavor and odor, color and appearance, texture and total acceptability) of UF-Feta cheese.
Results and discussion: The results indicated that fat reduction caused significant increment in the moisture content of UF-Feta cheese. The whey protein addition showed the same effect on moisture content as fat reduction whereas transglutaminase treatment decreased the moisture of UF-Feta cheese. As expected, fat reduction was accompanied by an increase in hardness and elasticity of UF-Feta cheese. Fat and moisture act as fillers in the casein matrix of cheese texture. When the fat content is decreased, the moisture does not replace the fat on an equal basis, so the total filler volume is decreased, resulting in lower moisture to protein ratio. This in turn increases possibilities of cross-linking between protein chains, resulting in a more compact cheese matrix with harder and chewier texture. Similarly, the increasing effect of TGase treatment on hardness and elasticity may be attributed to formation of a more compact protein matrix because of cross-linking action of enzyme on milk proteins. The whey proteins, however, decreased the hardness and elasticity of UF-Feta cheese. It seems that the added whey proteins increased the moisture content of cheese as sufficiently as to offset the decrease in the total filler volume caused by fat reduction, preventing the protein matrix to be more compact and elastic. Promoted protein-protein interactions of the cheese matrix resulting from fat reduction or TGase treatment might also account for our observation on decreased adhesiveness and increased cohesiveness. As the protein matrix becomes more compact, the cheese loses its adhesiveness. Conversely, as the number or strength of protein interactions increases, the structural integrity of cheese matrix called cohesiveness increases. Apart from fat, water can also create more open conformation for protein molecules, resulting in increased adhesiveness and decreased cohesiveness. This may justify our observation on higher adhesiveness and lower cohesiveness of whey protein-fortified low-fat cheeses with high moisture content. Not surprisingly, all the sensory attributes of UF-Feta cheese were adversely influenced by fat reduction. On the other hand, whey proteins improved the flavor and texture of low-fat UF-Feta cheeses. They, however, showed no effect on appearance score of cheese samples in spite of the fact that they somewhat compensated for lost lightness (L*) of low-fat cheeses. Similarly, TGase treatment did not affect the appearance acceptability of UF-Feta cheeses despite having significant effect on their L* value. The sensory panel did not appreciate the flavor of TGase-treated samples; however, they scored the samples treated with enzyme concentration lower than 1 U/g protein as having desirable texture. RSM suggested that the optimum formulation of 5.95% (w/w) fat, 0.56 unit TGase per gram protein and 8.79% (w/w) WPC could produce a low-fat cheese sample with desired textural (hardness 0.342 kg; elasticity 8.58 mm; adhesiveness -0.070 kg.s; cohesiveness 0.474) and sensory (overall sensory score 88.73 out of 100) attributes.
Hossein Jooyandeh; Vahid Samavati
Abstract
Introduction: Accumulation of free radicals could lead to permanent oxidative destruction of organisms by attacking macromolecules and organelles of the body, thus causing organism aging, fatigue and degenerative diseases. Therefore, discovering and developing safe and non-toxic natural antioxidants ...
Read More
Introduction: Accumulation of free radicals could lead to permanent oxidative destruction of organisms by attacking macromolecules and organelles of the body, thus causing organism aging, fatigue and degenerative diseases. Therefore, discovering and developing safe and non-toxic natural antioxidants has been an interesting topic in recent decades. Compared to synthetic antioxidants, extracts from plant resources usually have quite stable constructions and great antioxidant activities, and can easily be absorbed without dangerous immunoreactions. Many antioxidant compounds, naturally occurring from plant sources, have been identified as free radicals or active oxygen scavengers. Malva neglecta (MN), which is known as Panirak/Tooleh in Iran is an annual and herbaceous plant. The leaves and flowers of MN are used in traditional phytotheraphy and in treatment of cough, respiratory system and digestive system problems. The objective of this study was to optimize process conditions of extraction in order to obtain the highest yield from crude extract of MN leaves and identify its antioxidant properties. Materials and methods: Three-variable-three-level Box-Behnken design-response surface methodology (BBD-RSM) with five replications at central point was used to optimize the extracting parameters of crude extract from the MN leaves including extraction time (1-8 h), extraction temperature (50-100°C), and the water/solid ratio (3-30). The ability of extracted materials to scavenge the free radicals of DPPH, OH and super oxide was also evaluated by chemical analysis. Results and Discussion: All three independent variables effected the yield of crude extract of MN leaves. The extraction yield of MN crude extract significantly increased from 5.90% to 8.01% with extraction time varying from 1 h to 6 h. However, the yield was not altered meaningfully, as the extraction time was increased from 6 h up to 8 h. This may be due to degradation of the polysaccharides because of the extended extraction time. The extraction process was performed with temperatures from 50 °C to 100 °C, with the other extraction variables such as ratio of water to raw material and extraction time fixed at 13 ml/g and 3.5 h, respectively. The extraction yield of crude extract increased with increasing extraction temperature and peaked at 7.89 at 100 °C. Different ratios of water to raw material have considerable effect on extraction yield. In this study, we used ratios of water to raw material from 3 to 30 ml/g, with fixed parameters (extraction time and extraction temperature at 3.5 h and 75 °C, respectively). Extraction yield increased noticeably from 6.10 to 8.10 with ratio of water to material varying from 3 ml/g to 24 ml/g. As extraction time, at the higher experimental levels, as the ratio of water to raw material was increased (from 24 up to 30 ml/g) the yield of crude extract was not changed considerably. Under the appropriate condition of ratio of water to raw material, the crude extract molecules can swell thoroughly, and more compounds could dissolve in water to improve extraction yield. The determination coefficient (R2 = 0.9897) suggested that the model was valid, implying that 98.97% of the variation could be explained by the fitted model. The adjusted determination coefficient was used to evaluate the correlation between the experimental values and predicted values, and the outcome (R2Adj= 0.9794) suggested that the correlation was significant. The f-value (1.49) for “the lack of fit” indicated that the “lack of fit” was not significant relative to the pure error (p > 0.05). The CV for yield of MN leaves was 0.64%, which defined a good reliability of the experimental values. The adequate precision value 21.61 and PRESS 0.42 for our model indicated an appropriate model could be designed. On multiple regression analysis, the quadratic polynomial equation for the independent variables and response variable expressed as follows: Y =7.82 + 1.025X1 + 3.241667X2 + 2.031X3 + 0.525X1X2 - 0.7X1X3 + 0.675X2X3 – 0.206X12 – 0.21833X22 Where, Y is extraction yield (%); X1, extraction time (h); X2, extraction temperature; and X3, ratio of water to raw material (ml/g) Statistical analysis of the results showed that the optimal conditions for higher extraction yield were extraction time: 6 h, extraction temperature: 90oC, and the ratio of water to raw material: 19. Under these conditions, the experimental yield was 9.22% ± 0.47%, which well matched the predicted value (9.18%), under these conditions; the experimental yield was 9.18%. Furthermore, results obtained from chemical analysis showed that DPPH, OH and super oxide scavenging of MN crude extract increased rapidly with increasing of its concentration. DPPH scavenging rate of the crude extract was more than BHT standard (89% vs. 78%) at their maximum equivalent concentration (300 ppm). Furthermore, OH and super oxide scavenging ability of MN crude extract (87% and 91%, respectively) were significantly more than ascorbic acid standard solutions (74% and 81%, respectively) at their highest experimental concentrations (150 ppm). Based on our results, components extracted from Malva neglecta leaves may introduce as an antioxidant and free radical scavenger. This study could help food industries to add a new source of hydrocolloid with certain functionality as an alternative additive in different foods, cosmetic and pharmaceutical products.
