Food Chemistry
Zeinab Nooshi Manjili; Alireza Sadeghi Mahoonak; Vahid Erfani Moghadam; Mohammad Ghorbani; Hoda Shahiri Tabarestani
Abstract
Introduction
Seeds and nuts have received increasing attention due to their nutritional value and the high therapeutic properties of their bioactive compounds. Most of the seeds are used as nuts, and some of them are considered agricultural waste. Pumpkin seeds have a high content of protein (30–40% ...
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Introduction
Seeds and nuts have received increasing attention due to their nutritional value and the high therapeutic properties of their bioactive compounds. Most of the seeds are used as nuts, and some of them are considered agricultural waste. Pumpkin seeds have a high content of protein (30–40% in terms of dry matter). Proteins are among the vital health-giving components that provide nitrogen, essential amino acids and energy necessary for normal cells. Pumpkin seeds are a good source of amino acids such as valine, histidine, isoleucine, leucine, threonine and methionine. Protein hydrolysate is a mixture of peptides and amino acids that can show antioxidant, antimicrobial, anticancer, antidiabetic and antihypertensive properties. During hydrolysis, proteins are broken into small peptides and amino acids. Since enzymatic hydrolysis is performed in relatively mild conditions and no amino acid damage occurs, this type of hydrolysis is preferred over acid and alkaline hydrolysis. Hydrolysates obtained from pumpkin seed protein have bioactive properties, especially antioxidant activity. Pretreatment of proteins before enzymatic hydrolysis acts to improve the release of bioactive peptides from different proteins. Pretreatment can facilitate the unfolding the structure of proteins and thus increase the access of enzymes to peptide bonds. The main properties of microwaves usually show three characteristics: penetration, reflection and absorption. Microwave assisted enzymatic hydrolysis can shorten the time and improve the speed of the reaction. The purpose of this research was to investigate the antioxidant activity of pumpkin seed protein hydrolysates (Cucurbita maxima L.) by alcalase enzyme in two conditions: without pretreatment and using microwave pretreatment.
Material and Methods
In this study, Pumpkin (Cucurbita maxima L.) was purchased from the local market of Astane Ashrafieh in Gilan province. The seeds were scooped manuallyand then dried in an oven at 50°C for 72 hours. After the production of protein concentrate from pumpkin seeds, the chemical properties of the concentrate, such as the amount of fat, protein, ash and moisture, were measured. The isolated pumpkin seed solution was exposed to microwave energy with a power of 450-900 watts for 30–90 seconds and was used as a substrate solution in enzymatic hydrolysis experiments. It should be noted that after measuring the total antioxidantactivityr for different powers and times of microwave pretreatment, the power of 600 watts for 60 seconds was selected and applied before enzymatic hydrolysis. Enzymatic hydrolysis was done by alcalase enzyme with a concentration of 0.5 to 2.5% compared to the protein substrate during 20 to 190 minutes, and the optimum temperature and pH of alcalase were determined in order to produce hydrolysates with antioxidant activity. Antioxidant activity was measured by using DPPH free radical inhibition, total antioxidant activity and iron chelation activity methods.
Result and Discussion
Bioactive peptides produced by the enzymatic hydrolysis of proteins have significant antioxidant properties. Pumpkin seeds can be used as a rich source of nutrients and bioactive compounds in various food industries. The results showed that the maximum amount of antioxidant activity without pre-treatment was achieved in 165 minutes with a 2.2% ratio of E/S by using DPPH free radical scavenging activity (40.5%), total antioxidant power (0.79), and iron chelation activity (96.2%) methods. By using microwave pre-treatment, the maximum amount of antioxidant activity was achieved in a shorter time and with less enzyme (105 minutes and E/S ratio 1.5%) using DPPH free radical scavenging (52%), total antioxidant power (0.711), and iron chelation activity (93%). Therefore, it can be concluded that using microwave assisted enzymatic hydrolysis , in addition to achieving hydrolysates with proper antioxidant activity, is a suitable method to save time and reduce enzyme concentrations used in enzymatic hydrolysis.
Food Technology
Parisa Feizi; Yahya Maghsoudlou; Hoda Shahiri Tabarestani; Seyed Mahdi Jafari; Amir Bahri
Abstract
Introduction
Astaxanthin is a widely used carotenoid pigment in the food industry which is extracted from various natural and synthetic sources. Nowadays, due to the adverse effects of organic solvents green solvents which are non-toxic, non-volatile and environmentally friendly have been proposed. ...
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Introduction
Astaxanthin is a widely used carotenoid pigment in the food industry which is extracted from various natural and synthetic sources. Nowadays, due to the adverse effects of organic solvents green solvents which are non-toxic, non-volatile and environmentally friendly have been proposed. Therefore, this study focuses on comparison of the extraction of astaxanthin from shrimp (Fenneropenaeus merguiensis) and Gammarus (Pontogammarus maeoticus) under soaking conditions for 24 hours with organic solvent (combination of ethanol with ethyl acetate), green solvent (microemulsion of ionic liquid in water) and vegetable oil (sunflower oil). Ionic liquid microemulsion in water is considered a newnovel solvent for astaxanthin extraction. Determination of density, conductivity and diameter were the characteristics of microemulsion test. In extraction,Solvent to sample ratios of 5x, 12.5x and 20x were used for the extraction and compared with the control sample.
Materials and Methods
merguiensis and P. maeoticus With species approval were procured from Persian Gulf Ecology Research Institute (Iran). Commercial astaxanthin (>98 % purity), α-diphenyl-β-picrylhydrazyl (DPPH), and butylated hydroxytoluene (BHT) were procured from Sigma-Aldrich (USA). The HPLC grade ethanol, propanol, ethyl acetate,, tributyl octyl phosphonium bromide, Triton X-100, and n-butanol were obtained from Merck Chemicals Co. (Germany). Refined sunflower oil which was antioxidant-free, was also purchased from Hayat Company (Iran). The shell of F. merguiensis and P. maeoticus were carefully washed with distilled water, then freeze-dried (Christ-Alpha 1–4, LD freeze dryer, Germany) for 48 h at -50 °C. After sieving the powders with a laboratory sieve with a mesh smaller than 15 µm. The obtained powders were kept at Refrigerator. All experiments were done in the Food and Drug Administration Department of Hormozgan University of Medical Sciences.
Results and Discussion
According to the results, the density of the microemulsion was determined in the range of 0.97151 g/cm3, its diameter was 15.8 nanometers and the conductivity was 312 microsiemens at 27.1°C. The results of astaxanthin extraction with different solvents in the comparison with control solvent were statistically significant (p< 0.05). According to the results obtained from the extraction of astaxanthin from two sources of shrimp and gammarus, shrimp was selected as the source with the highest amount of extracted astaxanthin. The use of green solvent (ionic liquid microemulsion in water) in a ratio of 12.5 times solvent to sample was also chosen as the optimal method. The amount of astaxanthin extracted under optimal conditions was 77.44 ± 1.09 mg/ml. The results of DPPH radical inhibition by extracted astaxanthin using ionic, oily and organic solvents compared to synthetic antioxidant BHT showed that the antioxidant activity increased with increasing the concentration of astaxanthin, but this increase was always lower than BHT.
Conclusion
In general, the results of this research show that the use of microemulsion based on ionic liquids is a suitable alternative to conventional methods in extracting and recovering astaxanthin from natural biological sources.
Acknowledgement
We are grateful to the Honorable Vice-Chancellor of Hormozgan Food and Drug Administration for the help in using the Hormozgan Food and Drug Laboratory to conduct the experiments of this doctoral thesis.
Food Technology
Parisa Shahiri Tabrestani; Mahboobeh Kashiri; Yahya Maghsoudlou; Hoda Shahiri Tabarestani; Mohammad Ghorbani
Abstract
Introduction
There ...
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Introduction
There has been an increasing demand for functional analog meat products due to environmental, human health, and animal welfare concerns. Burger analogs are plant-based products that are designed to mimic the taste, texture, and appearance of meat burgers. They are typically made from a combination of plant-based ingredients such as textured vegetable protein, legumes, grains, and vegetables. The goal of burger analogs is to provide a meat-like experience without using animal-based products.These formulations aim to provide a healthier and sustainable alternative to conventional meat products. The organoleptic properties of burger analogs, including texture, taste, and aroma, are crucial for their acceptance by consumers.
Prickly pear (Opuntia stricta) is a fruit from the Cactaceae family that contains various beneficial components, including natural pigments, proteins, fibers, and polysaccharides. Pectic polysaccharides and arabinogalactans are two types of polysaccharides found in prickly pear that have thickening properties and can improve the texture of food products. Moreover, Prickly pear is a nutritious and functional fruit that can provide various benefits when incorporated into the diet or used as an ingredient in food products. To date, no health benefit analog burgers incorporating Opuntia fruit have been developed.This study investigated the effects of adding Prickly pear pulp powder at levels of 0.5-2.5% on the physicochemical, sensory, and textural properties of analog burgers.
Materials and Methods
Analog burgers were formulated according to Iranian national standards using common ingredients (texturized soy protein, water, canola oil, garlic, dehydrated onion, soy sauce, and guar gum) as a control sample. Mature prickly pear fruits (Opuntia stricta) were collected from west of Mazandaran province in February. The fruits were washed, peeled, and dried in a forced oven dryer at a temperature of 45 °C. The dried samples were then ground into a powder and stored at 4 °C until further physico-chemical parameters of the including moisture, pH, ash, protein, lipid, color and total phenolic content. For developing new formulation of analog burgers, the roasted flour was substituted with prickly pear pulp powder at 0.5%, 1.5%, and 2.5% of the base recipe. The average moisture, ash, fat, carbohydrate content, pH, holding capacity, and color of each raw packed burger were measured. The hardness, springiness, cohesiveness, and chewiness of cooked analog burgers were evaluated using a texturometer instrument. Sensory analysis was performed by 10 panelists who judged discrimination scales of color, odor, taste, and texture characteristics. Analysis and sample treatments were repeated at least three times. Statistical analysis was performed using SPSS (version 19.0), and data were expressed as means ± standard deviation (SD).
Results and Discussion
The lowest and highest cooking losses were observed in analog burgers with 2.5% pulp powder (21.03 ±0.47%) and the control (22.2 ± 0.63%), respectively. However, moisture retention and juiciness did not show significant differences (p > 0.05) between analog burgers with prickly pear pulp powder and the control. The results indicated that increasing prickly pear pulp powder levels significantly decreased the redness (+a*) parameter and yellowness (+b*) of raw analog burgers. Moreover, a reduction in cooking loss and shrinkage were observed for cooked soy burger samples using prickly pear pulp powder. However, cooked analog burgers with added prickly pear pulp powder showed significantly higher juiciness. The elasticity of the produced analog burgers significantly decreased with an increasing percentage of pulp powder (p <0.05).
Conclusion
The incorporation of prickly pear pulp powder in analog burger formulation resulted in a significant decrease in cooking loss and shrinkage of the cooked burgers, while not significantly affecting moisture retention and juiciness. An increase in prickly pear pulp powder levels in analog burger formulation led to a significant decrease in the redness and yellowness of the raw analog burgers, as well as a decrease in their elasticity. Based on the sensory evaluation and consumers' overall tendency to consume burgers, it is recommended to use 1.5% prickly pear pulp powder in analog burger formulation.
Food Chemistry
Maryam Rahimipanah; Alireza Sadeghi Mahoonak; Mohammad Ghorbani; Hoda Shahiri Tabarestani; Mohsen Nabimeybodi
Abstract
Introduction
High levels of free radicals can damage biomolecules and eventually cause oxidative stress. Bioactive peptides produced during enzymatic hydrolysis keep high health properties, such as antioxidant properties. The production of antioxidant peptides has received much attention as a ...
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Introduction
High levels of free radicals can damage biomolecules and eventually cause oxidative stress. Bioactive peptides produced during enzymatic hydrolysis keep high health properties, such as antioxidant properties. The production of antioxidant peptides has received much attention as a new generation of natural antioxidants. Plants are one of the most abundant sources of biopolymers, especially protein. As long as the protein structure is intact, its amino acid sequence is inactive; however, during proteolysis, fermentation, and gastrointestinal digestion, these amino acids are released as oligopeptides ordinally with less than 20 amino acids and below 10 kDa in molecular weight. These peptides are more digestible and can exhibit specific bioactive properties such antioxidant properties. In this regard, the use of food waste containing protein to produce bioactive peptides and increase their value has received increasing attention. Enzymatic hydrolysis can increase their functional properties by converting proteins into peptides without affecting their nutritional value. Pomegranate seed protein is a by-product of the pomegranate seed oil industry and can be a good source of bioactive peptides with antioxidant properties. According to our knowledge, there isn’t any data about the enzymatic hydrolysis of pomegranate seed protein for antioxidant peptides production. In this study, the optimal conditions for enzymatic hydrolysis of pomegranate seed protein with trypsin using the responses surface method and the effect of hydrolysis on protein structure were investigated.
Materials and Methods
In this study, the protein was extracted from pomegranate seed, and using trypsin the optimization of enzymatic hydrolysis conditions of protein was determined by Face-Centered Central Composite design, which is one of the responses surface design methods. The effect of independent variables including temperature (30 to 45 °C), time (30 to 180 minutes), and enzyme to substrate ratio (1 to 3 w/w) on DPPH free radical scavenging activity and Fe+3 reducing power as responses, was evaluated. Validation tests were performed for confirmation of the proposed values by software and the degree of hydrolysis of the samples was determined. In the next step, the unhydrolyzed and hydrolyzed protein was evaluated for molecular weight distribution and their surface hydrophobicity was compared. Finally, scanning electron microscopy images were used to confirm the hydrolysis process.
Results and Discussion
Under optimal conditions obtained from the response surface method (temperature: 37.6 °C, time: 136.55 minutes, and enzyme to substrate ratio: 2.2%), trypsin-derived hydrolyzate, showed DPPH free radical scavenging power: 87±0.89% and Fe+3 reduction power: 0.293±0.44. Under these conditions, the degree of hydrolysis was equal to 30.1±1%. The optimum conditions of hydrolysis were validated by RSM. The increase in the surface hydrophobicity of the protein after the hydrolysis process indicated the unfolding of the pomegranate seed protein chain and the exposure of its structure during the reaction. The electrophoretic profile of denatured pomegranate seed protein showed smaller peptide bands and lower band intensity, along with losing some of the peptide fractions after hydrolysis. so the efficacy of trypsin at cleaving the protein was confirmed. Evaluation of images obtained by scanning electron microscopy showed that unhydrolyzed protein had complex structures comprised of random sheets of different sizes and shapes and the protein degraded into small fragments and looser structure with many folds after enzyme hydrolysis, resulting in smaller particles compared with untreated samples with the same SEM parameters
Conclusion
Considering the consumer’s tendency toward functional foods and present concerns about the application of synthetic additives and according to the results, the hydrolyzed pomegranate seed protein prepared by trypsin shows good antioxidant capacity. In addition, there will be a reduction in waste generated by the pomegranate processing industry. Further studies will need for the isolation and identification of the specific peptides and amino acid sequences and the evaluation of their possible incorporation in food matrices.
