Food Chemistry
Mohammad Taghi Golmakani; Gholam Reza Mesbahi; Nasireh Alavi; Azita Hosseinzade Farbudi
Abstract
Introduction: Food wastes and losses are produced during all phases of food life cycles. The highest wastes belong to the processing of fruits and vegetables. Bioactive compounds have the potential to be extracted from the by-products of fruits and vegetables which can be used in the food processing. ...
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Introduction: Food wastes and losses are produced during all phases of food life cycles. The highest wastes belong to the processing of fruits and vegetables. Bioactive compounds have the potential to be extracted from the by-products of fruits and vegetables which can be used in the food processing. Extraction of flavor compounds, phenolic compounds, enzymes, and organic acids from wastes of fruits – pomace, peel, and seeds of citrus fruits, pomace and leave of apple, seeds of grape, and peel of kiwifruit – and vegetables – pomace of carrot, husk of garlic, skin of onion, peel of potato, and skin of tomato – have been reported (Sagar et al., 2018).Sour orange, Citrus aurantium, is one of the species of citrus fruits. Sour orange seeds contain fats, protein, and bitter compounds which affect citrus processing (Ye et al., 2017). Naringin, neohesperidin, flavon, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid have been detected in methanolic extract of sour orange seeds (Bocco et al., 1998).Bioactive compounds are recovered from food wastes through various conventional and novel extraction techniques. Microwave-assisted extraction is one of the most used novel and environmentally friendly extraction methods. Advantages of microwave-assisted extraction over conventional extraction techniques include automated operation, more effective and selective heating, and less extraction time (Vinatoru et al., 2017).The objective of this study was optimization of microwave-assisted extraction of sour orange seed coat extract in terms of microwave power level, extraction time, sample quantity, and solvent volume on yield, bioactive compounds (total phenolic content and total flavonoid content), and antioxidant activity (free radical scavenging activity, ferric ion reducing antioxidant power, cupric ion reducing antioxidant capacity, and ferrous ion chelating). Also, optimum conditions of microwave-assisted extraction was compared to that of conventional magnetic stirrer-assisted extraction method. Materials and methods: Sour orange seeds were purchased from Limondis Company (Beyza, Fars province, Iran). Microwave-assisted extraction conditions including microwave power level (100, 200, and 300 W), extraction time (5, 10, and 15 min), sample quantity (5, 10, and 15 g), and solvent (methanolvolume 100, 150, and 200 mL) were optimized. Yield, bioactive compounds (total phenolic content (Habibi et al., 2015) and total flavonoid content (Habibi et al., 2015)), and antioxidant activity (free radical scavenging activity (Habibi et al., 2015), ferric ion reducing antioxidant power (Rekha et al., 2012), cupric ion reducing antioxidant capacity (Pascu et al., 2014), and ferrous ion chelating (Oyetayo et al., 2009)) of sour orange seed coat extract were evaluated. After determining the optimum conditions of microwave-assisted extraction, yield, bioactive compounds (total phenolic content and total flavonoid content), and antioxidant activity of sour orange seed coat extract were compared to those of conventional magnetic stirrer-assisted extraction method. Design Expert software (Version 10, Stat-Ease, Minneapolis, MN) was employed for analyzing four variables – microwave power level, extraction time, sample quantity, and solvent volume – at three levels consisting 30 experimental runs. Response surface methodology concerning central composite design (6 center points, quadratic model, and face center = 1) was applied. Results and discussion: Optimum conditions of microwave-assisted extraction were microwave power level of 200 W, extraction time of 12 min, sample quantity of 5 g, and solvent volume of 200 mL. Under optimum conditions, yiled, total phenolic content, total flavonoid content, IC50, ferric ion reducing antioxidant power, cupric ion reducing antioxidant capacity, and ferrous ion chelating were11.57%, 15550.50 µg gallic acid equivalent/g, 1476.22 µg quercetin equivalent/g, 11.33 mg/mL, 7.12 mg ascorbic/g, 6.44 mg ascorbic acid/g, and 0.43 mg EDTA/g, respectively. Intermediate microwave power level (200 W) can be more suitable from an industrial perspective and energy consumption (Jokić et al., 2012). Further increase in microwave power level, i.e. higher than 200 W, causes thermal degradation of bioactive compounds (Dahmoune et al., 2013), decreasing total phenolic content, total flavonoid content, and antioxidant activity of sour orange seed coat extract. The highest extraction time gives the bioactive compounds a chance to diffuse and release from the cell matrix to the surrounding environment (solvent). The highest solvent volume was selected as the optimum extraction condition. By increasing solvent volume up to 200 mL, meaning a greater gradient in bioactive compound concentration, mass transfer was also improved (Dahmoune et al., 2013). Also, the minimum sample quantity (5 g) was determined in optimum conditions. Increasing sample quantity (while the solvent volume remained constant) reduces the surface area available for the solvent to penetrate the sample matrix. As a result, higher sample quantity caused lower extraction of bioactive compounds (Ballard et al., 2010). There were no significant differences between yield, bioactive compounds, and antioxidant activity of extract obtained by conventional-assisted extraction method in comparison with those of microwave-assisted extraction. In conclusion, microwave-assisted extraction, as a green and fast method, can be proposed as a suitable and practical method for extraction of bioactive compounds from sour orange seed coat.
Mohammad Reza Toorani; Reza Farhoosh; Mohammad Taghi Golmakani; Ali Sharif
Abstract
Introduction: Lipid oxidation is one of the most important factors affecting the loss of quality or the deterioration of edible oils. This reaction is accompanied by the production of harmful compounds that may threaten consumer’s health. Several parameters affect the severity of the oxidation ...
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Introduction: Lipid oxidation is one of the most important factors affecting the loss of quality or the deterioration of edible oils. This reaction is accompanied by the production of harmful compounds that may threaten consumer’s health. Several parameters affect the severity of the oxidation reaction, among them temperature is one of the most important parameter to consider. Lipid oxidation increase significantly with the increase of temperature, which drastically reduces the length of the shelf life of the oils. Numerous methods have been used to postpone the oxidation of oils that one of the most useful methods is the addition of antioxidants. Nowadays, natural antioxidants have been located in the hotspot of attention from safety and sensory characteristics point of view. Sesamol as a valuable natural antioxidant may help to provide healthy edible oils. The determination of thermal kinetic data and the evaluation of thermodynamic indices have long been used to the better identify the mechanisms and the events caused by temperature elevation. Examining the temperature and time variables together and merging these components could provide valuable information about the environmental effects of foodstuffs. These parameters are particularly important for edible oils. Hence, the kinetic-thermal information of the oils oxidation in the presence of sesamol may provide the valuable assistance in explaining the storage conditions of various edible oils in the presence of this antioxidant. Materials and methods: The sesamol's ability to quench free radicals was determined by DPPH test and at 517 nm. The oil purification process was performed by adsorption column chromatography in order to eliminate minor components that may be interfere with the oxidation reaction. The evaluation of the accelerated oxidation process in presence of sesamol was carried out in a dry oven and through monitoring the accumulation of hydroperoxides (peroxide value) over time at 60, 80 and 100 °C. The peroxide value was measured spectrophotometrically at 500 nm. The induction period of oils oxidation was determined through two lines fitted on initiation and propagation steps of the oxidation curve. The rate constants of the oils oxidation and sesamol consumption, the peroxide value corresponding to the length of induction period (PVIP), the minimum sesamol concentration to demonstrate the antioxidant activity and the oxidative stability time of lipid systems at ambient temperature were also determined by oxidation kinetic data. Results and discussions: The results of inhibitory test showed that the amount of sesamol required to inhibit 50 percent of the DPPH radicals is equal to 1 mM. The induction period of olive oil has reached to over 520 h in presence of 0.01% sesamol at 60 °C, whereas sesame and canola oils were placed in the subsequent positions with nearly 330 and 325 h, respectively. The average extent of PVIP (all sesamol concentrations) for two lipid systems i.e. sesame and canola oils was close to each other and drastically higher from olive oil. This delocalization of the numbers suggests that the PVIP is independent of the antioxidant concentration available and is affected by the fatty acids structure of oils. The effect of temperature elevation on the rate constant of oxidation for different oils did not follow the same pattern, so that the slope of increase of the rate constant for olive oil was very mild than to the other two oils. The results showed that the increase in temperature has markedly increased the rate of sesamol consumption, so that unsaturated lipid systems have undergone significant changes in this regard. Increasing the temperature increased the minimum concentration required for the antioxidant activity of sesamol. This pattern was linear for olive oil and hyperbolic for sesame and canola oils.
Mohammad Taghi Golmakani; Marzieh Moosavi-Nasab; Malihe Keramat; Azin Azhand
Abstract
Introduction: Wheat germ is a by-product of wheat milling industry. It contains about 11% oil. Wheat germ oil is well known as a tocopherol rich food lipid. It also contains more than 55% polyunsaturated fatty acids, mainly linoleic and alpha-linolenic acid (Simopoulos 1999; Schwartz et al. 2008). Wheat ...
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Introduction: Wheat germ is a by-product of wheat milling industry. It contains about 11% oil. Wheat germ oil is well known as a tocopherol rich food lipid. It also contains more than 55% polyunsaturated fatty acids, mainly linoleic and alpha-linolenic acid (Simopoulos 1999; Schwartz et al. 2008). Wheat germ processing presents challenges due to its high content of bioactive compounds. Microwave-assisted extraction is a new extraction technology used for the extraction of bioactive compounds, which is based on combination of microwave and conventional solvent extraction. This technique which is used has many advantages such as short time, less solvent usage, and higher extraction yield (Hao et al. 2002).Common Kilka (Clupeonellacultriventris caspia) oil is considered as one of the most healthy and functional oils. It is highly rich in polyunsaturated ω-3 fatty acids such as eicosapentaenoic acid and docosahexaenoic acid. However, Kilka oil is highly vulnerable to oxidation due to its high content of poly unsaturated fatty acids. Oxidations of poly unsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid result in a number of oxidation products that have negative impacts on the flavor and odor of Kilka oil, and also can affect the amount of these fatty acids that are made available to the body (Lin and Lin 2004; Fazli et al. 2009; Pazhouhanmehr et al. 2015; Yu et al. 2002). In order to preserve polyunsaturated fatty acids of Kilka oil from oxidative degradation, the use of novel and effective antioxidants can offer methods to maintain the health of consumers.The objective of this study was to investigate the effect of microwave-assisted extraction method on extraction yield and some chemical characteristics of wheat germ oil in comparison with conventional Soxhlet method. Also, wheat germ oil was investigated as a natural antioxidant for improving oxidative stability of Kilka oil.
Materials and methods: Wheat germ used in this research was supplied from Sepidan Flour Mill (Shiraz, Iran). Crude Kilka oil with no added antioxidants was supplied by a local fishery factory (Rasht, Iran).Wheat germ samples were pretreated with microwave at 200 W for 5 min. Thereafter, the samples were extracted with Soxhlet method. Samples were analyzed at 2, 4, 6, 8, and 10 h of extraction process. Extraction yield, saponification value, acid value, iodine value, and fatty acid profile of wheat germ oil extracted with microwave-assisted method were compared with those extracted with conventional Soxhlet method. Fatty acid composition of wheat germ oil was determined according to the method described by Golmakani et al. (2012) with some modifications. Saponification, acid, and iodine values of wheat germ oil were determined by using the AOAC official methods (AOAC 2000). Wheat germ oil was added to Kilka oil at a concentration of 1000 ppm. For the control, Kilka oil without any added antioxidant was used. Peroxide, anisidine, and Totox values of wheat germ oil were measured during 15 days storage at 60 °C. Peroxide, anisidine, and Totox values of wheat germ oil were determined using the AOCS official methods (AOCS 2000). Induction period was considered as the number of days required for a sample to reach a PV of 20 meq O2/kg (Keramat et al. 2016).
Results and discussion: The microwave-assisted extraction method increased the extraction yield of wheat germ oil by 15-27%. Increase in extraction yield is due to cell membrane rupture by microwave which results in greater porosity, enabling the passage of oil from the cell membrane (Uquiche et al. 2008). The amounts of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in samples extracted by microwave-assisted extraction method were similar to those extracted by conventional Soxhlet method. Acid value of samples extracted by microwave-assisted extraction method was slightly higher than those extracted by conventional Soxhlet method. This result is in agreement with the previous studies (Kiralan et al. 2014; Uquiche et al. 2008). The saponification value of wheat germ oil sample extracted by microwave-assisted extraction method was 9.65% higher than those extracted by conventional Soxhlet method. Thus, wheat germ oil sample extracted by microwave-assisted extraction method contained higher short chain fatty acids than those extracted by conventional Soxhlet method. The iodine value of wheat germ oil sample extracted by microwave-assisted extraction method was lower than those extracted by conventional Soxhlet method. Accordingly, microwave-assisted extraction method has a positive effect on the oxidative stability of wheat germ oil. Wheat germ oil significantly decreased the peroxide, anisidine, and Totox values of Kilka oil by 61.59%, 65.01%, and 61.97%, respectively, compared to the control. The induction period and protection factor of Kilka oil sample containing wheat germ oil (120.20 h and 1.42, respectively) was significantly higher than those of control sample (84.40 h and 1.00, respectively). The inhibitory effect of wheat germ oil against Kilka oil oxidation can be attributed to the presence of high amounts of biological active compounds. Based on the results of this study, microwave extracted wheat germ oil can be proposed as a natural antioxidant for improving oxidative stability of Kilka oil.
Maryam Nejadmansouri; Seyed Mohammad Hashem Hosseini; Mehrdad Niakosari; Gholam Hossein Yousefi; Mohammad Taghi Golmakani
Abstract
Adequate consumption of ω-3 essential fatty acids (EFAs) has a positive impact on human health. EFAs-enriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions ...
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Adequate consumption of ω-3 essential fatty acids (EFAs) has a positive impact on human health. EFAs-enriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions developed by sonication method were subjected to various analyses as a function of hydrophilic lipophilic balance (HLB) and surfactant to oil ratio (SOR). Analyses were performed upon production and during 1-month storage at two temperatures (4 and 25 ˚C) in the presence (100 ppm) or absence of α-tocopherol. Increasing in HLB and SOR decreased the particle size and surface tension; while, increased the refractive index and viscosity. During storage, the particle size of α-tocopherol-loaded nanoemulsions decreased; whereas, that of α-tocopherol-free nanoemulsions increased in a temperature-dependent manner. Irrespective of the storage temperature, surface tension values of antioxidant-loaded nanoemulsions remained constant. However, their viscosity values increased. Antioxidant incorporation fairly increased the nanoemulsions stability likely due to partitioning at the interface. TEM micrographs confirmed the results obtained by static light scattering. The results of this study may help the rational design of functional foods using nanoemulsion-based delivery systems.
Maryam Farahmand; Mohammad Taghi Golmakani; Asgar Farahnaki; Gholam Reza Mesbahi
Abstract
Introduction: The pomegranate (Punica granatum L.) belongs to the family Punicaceae, which is planted around the world in different microclimatic areas. The pomegranate production has grown uninterruptedly, which is presumably due to the increasing consumer awareness of the benefits attributed to pomegranate ...
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Introduction: The pomegranate (Punica granatum L.) belongs to the family Punicaceae, which is planted around the world in different microclimatic areas. The pomegranate production has grown uninterruptedly, which is presumably due to the increasing consumer awareness of the benefits attributed to pomegranate and its polyphenols. Pomegranate fruit has valuable compounds with functional and medicinal effects like antioxidant, anticancer, and anti-atherosclerotic effects. Storage of juice concentrate can have a dramatic impact on physicochemical quality. The bioactive compounds and antioxidant activity in fruit juice products are influenced by many external factors like different storage temperatures. Knowledge of the rheological behaviour of juice products is essential for product development, design and evaluation of process equipment like pumps and piping. Pomegranate concentrate is so susceptible to the condition of storage, which results in a reduction in consumer acceptability and quality losses. Accordingly, the industrial concentrate stores frozen (-20 °C) which has a lot of costs to the producer. The objectives of this study were to evaluate the degradation visual color, the rheological characteristics of pomegranate juice concentrates, the stability of phytochemicals, the antioxidant activity, and the haze formation of reconstituted pomegranate juice concentrate during storage at different temperatures to determine the best storage conditions to reduce the quality losses and solving the problem about high cost of storage.
Materials and methods: The concentrated pomegranate (Punica granatum (L.) cv. Rabab) juice used in this study supplied from Narni (Green farm, Neyriz, Iran) factory. The pomegranate juice concentrate was poured into falcons for measuring physicochemical attributes, and micro tubes for determination of antioxidant activities. Then the samples were divided into four parts and stored equally in four different temperatures (-20, 4, 20, and 35 °C). The control samples were stored at -80 °C as fresh sample for the storage period (140 days). Folin-Ciocalteu reagent and 2,2-diphenyl-1-picrylhydrazyl radical (DPPHº) were supplied from Sigma-Aldrich Company (St. Louis, MO, USA). All other chemicals were of analytical grade and purchased from Merck Company (Darmstadt, Germany). The total soluble solid (TSS) was determined with a digital refractometer (Carl Zeiss, Germany). Total insoluble solid was measured by centrifugation at (5,000 × g) according to the IFFJP method 60, using a high speed centrifuge (Ibarz et al., 2011). The haze formation of reconstituted juice was determined by “settling” in a glass tube for 3 hour at room temperature. Color measurements of the juice samples were carried out using a HunterLab (CHROMA METER CR-400/410, KONICA MINOLTA, Japan) after dilution. The rheological characteristics of the pomegranate juice concentrate stored in different temperatures were studied by using a computer controlled rotational viscometer. Sample compartment was monitored at a constant temperature (25°C) using a water bath/circulator, while TSS was 65 °Brix. The viscosity measurements, was carried out According to the methods described by Cárdenas et al., (1997), using a Brookfield cone and plate viscometer (DVII pro Brook field, USA) between the shear rate of 0.5–200 (1/s). Total phenolic content of samples was measured according to the Folin-Ciocalteu colorimetric method (Sun et al., 2007). Total flavonoid content in juices was determined via a spectrophotometer according to the method of Chang et al. (2002). Radical scavenging activities of the samples were measured by using DPPHº as described by Mazidi et al., (2012). The ferrous ion reducing antioxidant power (FRAP) of the samples was measured calorimetrically according to the method by Fawole and Opara (2013). All analyses were performed by the Statistical Analysis System (SAS) software V 9.1 (SAS Institute, Inc., Cary, NC, USA). By using the analysis of variance (ANOVA), the differences among means were determined for significance at P< 0.05.
Results and discussion: The industrial pomegranate juice concentrate stored at (-20, 4, 20, and 35 °C) for 20 weeks, and some physicochemical properties like the second turbidity, CIE Lab color parameters, the rheological properties, the bioactive component (total phenolic and flavonoid contents), and antioxidant properties (FRAP and DPPH) investigated in order to determine the best condition of storage. The second turbidity was obvious among the samples stored at 35 °C in the last fourth weeks. Although there were no significant differences among L* value of the samples stored at -20, 4, and 20 °C, a* and b* value of the samples stored at -20 and 4 °C had the same reduction trend for 14 weeks. Even though the control samples had shear thinning behavior, the samples showed a dilatant behaviour after storage. Antioxidant activities measured via DPPH and FRAP sowed reduction with increasing time and temperature. Flavonoid content increased by increasing time and temperature. In conclusion, storage at 4 °C for 14 weeks was the best storage condition to keep the quality and reduce the costs.
Zahra Emam-Djomeh; Manuchehr Hamedi; Seyed Hadi Razavi; Mohammad Taghi Golmakani
Abstract
In this study the antimicrobial effects of essential oils from dill and coriander seeds on
staphylococcus aureus, Escherichia coli O157:H7 and salmonella typhimuruim were investigated and
the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each
essential oil ...
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In this study the antimicrobial effects of essential oils from dill and coriander seeds on
staphylococcus aureus, Escherichia coli O157:H7 and salmonella typhimuruim were investigated and
the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each
essential oil were determinate. For this purpose 5 concentration of each essential oils (125, 250, 500,
1000, 2000 and 4000 ppm) were chosen. For microbial count, Broth Dilution Test with Mueller
Hinton Agar and Broth were used. Results showed that Staphylococcus aureus had more susceptibility
and Salmonella typhimuruim was the resistant one. Our results also showed that essential oil from
coriander seed had more antimicrobial effect on the gram-negative bacteria. The essential oil from
coriander seed had MIC and MBC equal to 1000ppm and the essential oil from dill seed had MIC
equal to 500ppm and MBC equal to 1000 ppm against Staphylococcus aureus.
Key word: Broth Dilution Test, Staphylococcus aureus, Escherichia coli O157:H7, Salmonella
typhimuruim, essential oils, dill seed, coriander seed
