Elham Azarpazhooh; Parvin Sharayei; Farzad Gheibi
Abstract
Introduction: The current study was carried out to investigate the kinetics of infusion of phenolic compounds extracted from grape pomace (Argol) into Aloe vera gel cylinders. Aloe vera gel was treated at 50 °C in different osmotic solution with (40, 50 and 60) % sucrose plus (10, 20 and 30) % Argol, ...
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Introduction: The current study was carried out to investigate the kinetics of infusion of phenolic compounds extracted from grape pomace (Argol) into Aloe vera gel cylinders. Aloe vera gel was treated at 50 °C in different osmotic solution with (40, 50 and 60) % sucrose plus (10, 20 and 30) % Argol, for 0–120 min. The fruit to solution ratio was kept 1:4 (w/w) during all experiments. A two parameters model was used for prediction of kinetics of mass transfer and values of equilibrium moisture loss and solid gain. Moisture and solid effective diffusivities were estimated using Fick’s second law of diffusion. Results showed that Azuara model has the potential for estimating the equilibrium points. In addition, a good correlation between predicted and experimental values were obtained by this model. Besides, moisture and solid effective diffusivities increased by increasing sucrose solution and Argol from 40 to 50 percentage and 10 to 20 percentages, respectively. Moisture and solid diffusivities were found in the range of 0.61–4.23×10−9 m2/s and 2.13 –2.77 × 10−9 m2/s, respectively. Functional food is an emerging field in food science due to its increasing popularity with health-conscious consumers and the ability of marketers to create new interest in existing products. New by-product application should be investigated to have a positive environmental impact or to turn them into useful products. The use of by-product such as the grape juice pomace (Argol), results in the return of these valuable sources into the food cycle as well as an improvement in nutritional value and functional products in the food industry. Red grape (Vitis vinifera L.) pomace contains a large amount of polyphenolic compounds, therefore extraction of bioactive compounds promote human health. It is not as easy to mix the functional ingredient in the solid system as it is, in the case of the powder and liquid products. With the help of osmotic dehydration, many researchers have demonstrated the infusion of active compounds such as mineral, phenolic compounds, curcuminoids, probiotics and vitamins into solid food tissue. Fruits such as aloe vera, which have a short shelf life and are suitable system models for infusion of phenolic compounds during osmotic dehydration. Osmotic dehydration can prove useful in drying aloe vera (Aloe Barbadensis Miller) which contains several nutritional compounds, including polysaccharides, phenolics, antioxidants, vitamins, enzymes, minerals, and so forth. The phenomenon of osmotic dehydration can be modeled by the fundamentals of mass transfer that describe the origin of the diffusive forces that are involved in and control these processes. A two-parameter equation of Azuara was used to predict the kinetics of osmotic dehydration and the final equilibrium point. The internal mass transfer occurring during osmotic dehydration of food is usually represented by Fick’s second law which is the best known phenomenological model to represent the diffusional mechanism is the model of Crank, consisting of a set of solutions of Fick’s law of diffusion for different geometries, boundary conditions and initial conditions. To date, there is no research on mass transfer during osmotic dehydration of aloe vera. Therefore, the objective of the present work was the infusion of Argol phenolic compounds in alo vera gel through osmotic dehydration treatment to investigate mass transfer during osmotic treatment.
Material and methods: The Aloe Vera was added to agar and shaped into cylindrical pieces (20×20 mm). Afterwards the pieces were floated in a solution of sugar (40, 50 and 60) percentage and Argol (10, 20 and 30) percentage. The weight ratio of osmotic medium to fruit sample was 4:1 to avoid significant dilution of the medium and subsequent decrease of the driving force during the process. The experiment was performed with constant temperature of 50 °C. Samples were removed from the solution at 30, 60, 90, 180, and 120 min of immersion, drained and the excess of solution at the surface was removed with absorbent paper. Afterward, the dehydrated samples from each group were drained and blotted with absorbent paper to remove excess solution. Each assay was made in triplicate. Weight and moisture content of the samples, and moisture loss (ML) and solid gain (SG) were calculated. The curves of moisture loss and salt gain as a function of time were constructed using experimental data. A two parameters model was used for prediction of kinetics of mass transfer and values of equilibrium moisture loss and solid gain. Moisture and solid effective diffusivities were estimated by using Fick’s second law of diffusion.
Results and discussion: Results showed that in all of the studied conditions, the levels of moisture loss and solid gain had a non-linear increase with more floatation time in the solution. Moreover, the absorption rate of solid gain was faster in the beginning but eventually slowed down. Azuara model has the potential in estimating the equilibrium points. In addition, a good correlation between predicted and experimental values was obtained by this model. Besides, increasing the concentration of sucrose and Argol from 40% to 50% and 10% to 20% respectively, the coefficient of effective penetration for both parameters (water loss and solid substance absorption) improved. In addition, the coefficient of effective penetration displayed that different levels of sucrose and Argol had a notable effect on this coefficient.
Parvin Sharayei; Hossein Chaji
Abstract
Introduction: Saffron (Crocus sativus) is the most expensive kind of spice in the world while around 400 tons of saffron are estimated to be produced in the current Iranian year (March 2016-17) from 90,000 hectares of land under saffron cultivation across the country. But, high share of producing saffron ...
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Introduction: Saffron (Crocus sativus) is the most expensive kind of spice in the world while around 400 tons of saffron are estimated to be produced in the current Iranian year (March 2016-17) from 90,000 hectares of land under saffron cultivation across the country. But, high share of producing saffron is exclusively dedicated to produce and dry saffron stigma as whereas their violet color petals are mostly ignored and disposed. Saffron petal is one of the most economical sources of anthocyanin pigments. Attractive colour, functional properties and antioxidant properties of anthocyanins can make them a good substitute for synthetic pigments in the food industry. But, due to high moisture content of petals, 96.36% db, they must be dehydrated immediately to prevent the decay. In the meanwhile, the drying conditions are also too critical to petal sensitive compounds while the method of drying along with drying period and the amount of energy consumed, obviously play a significant role on price and quality of the final product.
Materials and methods: In this study, the optimization of the thin layer drying conditions of saffron petal was investigated using response surface methodology (RSM) and Face Centered Experimental Design (FCED) in order to designate the empirical expriments. Saffron petals were dried at different temperatures (40, 50 and 60◦C) and air velocities (0.7, 1.4 and 2.1 m.s-1) in a thin layer dryer and quantitative and qualitative characteristics of saffron petals (color )L: brightness; a: red – green; and b: blue-yellow, total phenolic compounds (TPC), total anthocyanin components (TAC), scavenging activity of DPPH (RSA), ferric reducing-antioxidant power (FRAP) and minimized 50% of radical-scavenging activity (IC50) contents) were invetigated.
Results & discussions: Maintaining the quality of final dried product as high as possible is a major concern while it is an important aspect to consider for use of phenolic compounds and anthocyanins as antioxidants and colorants in food industry. The results showed that the total phenolic compounds (TPC) and total anthocyanin content (TAC) had a remarkable increase with temperature rise from 40 to 50◦C while more temperature increase brought about sharp drops. But, an increasing trend of variations is observed in parallel with increases in velocity of drying air for each temperature. The rise in anthocyanin and phenolic content is more attributed to much significant reduction in drying duration from 40 to 50◦C in comparison with 50 to 60◦C. It was also observed that total antioxidant activity of dried saffron petals showed the same response as TPC and TAC to temperature rise from 40 to 50◦C. Such behaviour could be explained by the findings of other researchers in which the antioxidant activity has high correlation with anthocyanin content and total phenolic composition of food materials. As a complementary, it can be mentioned that polyphenols in an intermediate stage of oxidation have greater antioxidant power than initially even though this is temporary; furthermore high temperature stabilization procedures may lead to the formation of new compounds with higher antioxidant activity. This is essentially the case of the Maillard reaction, which creates various Maillard reaction products, with markedly higher antioxidant power.
Conclusion: Generally, according to Derringer’s desired function approach, the optimal conditions were 50◦C and 1.4 m.s-1.The experimental values agreed with those predicted values. At this optimum condition, the TPC, TAC, DPPH, FRAP, and a value of the dried saffron petal were found to be 46.39 mg/ g ,1205.58 mg/l, 52.97%, 1276.52 µmol Fe2+/l, and 11.13, respectively. The experimental values were in a good agreement with the predicted values.
Hassan Mirhojati; Parvin Sharayei; Reihaneh Ahmadzadeh Ghavidel
Abstract
The acidified ethanol extracts of dried barberry which have a relatively high anthocyanin content (376.28± 1.45 mg c3g/Kg dmp) were freeze dried using maltodextrin (MDX), polyvinyl-pyrrolidone (PVP) and mixture of MDX and calcium alginate (MDX-CaAlg) as a carrier and coating agents. The qualitative ...
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The acidified ethanol extracts of dried barberry which have a relatively high anthocyanin content (376.28± 1.45 mg c3g/Kg dmp) were freeze dried using maltodextrin (MDX), polyvinyl-pyrrolidone (PVP) and mixture of MDX and calcium alginate (MDX-CaAlg) as a carrier and coating agents. The qualitative attributes of the powders were characterized by their productively encapsulation efficiency, moisture content, bulk density, colour values (L*, a*, b*, C and H° ), particle size, total phenolic compounds (TPC), free radical scavenging activity of DPPH (RSA), ferric reducing-antioxidant power (FRAP) and minimized 50% of radical- scavenging activity (IC50). Scanning electron microscope was used for monitoring the structures of the powders. To determine the stability and half- life period of microencapsulated pigments, samples were stored under different storage temperatures (4◦C and 25◦C) at relative humidity 75%. Results showed that the encapsulated powder containing PVP 8% as wall material represented the best powder quality (p
Soudabeh Einafshar; Parvin Sharayei; Mozhgan Shormij; Razieh Niazmand
Abstract
Saffron is the most important Iranian non oil export. Improper conditions of saffron flower storage increases microbial contamination and decreases saffron quality. This study was done for prolonging the shelf life of saffron flower in modified atmosphere packaging and subsequent to producing a new method ...
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Saffron is the most important Iranian non oil export. Improper conditions of saffron flower storage increases microbial contamination and decreases saffron quality. This study was done for prolonging the shelf life of saffron flower in modified atmosphere packaging and subsequent to producing a new method for exporting the fresh saffron flower as cut flower. Saffron flowers were packed in a polymer (Polyamide- Polyethylene bags) and three gas combinations of CO2, O2, and N2 (30%,5%,65%; 50%,5%,45% and 70%,5%,25% respectively). Samples and Control (without packaging) were kept at 0˚c for 15 days. Every three days the concentrations of oxygen and carbon dioxide inside the packages, the yield of product, physical (weight loss, percent of the flowers welter, the length and diameter of fresh stigma) and chemical properties (percent of moisture and the amount of Crocin, Safranal and Picrocrocin of dried stigma) were measured. The existence of E.Coli and enumeration of yeasts and moulds also were done. The results showed that modified atmosphere packaging increased the shelf life of saffron flowers. The chemical and physical qualities of control were lost strongly during 9 days. There were no evident for E.Coli growth in the samples. Enumeration of yeasts and moulds showed that most treatments were seen the national standard of Iran (103cfu/gr).
