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.
Elham Ranjbar Nedamani; Alireza Sadeghi Mahoonak; Mohammad Ghorbani; Sharlot Jakobson; Vahid Khori
Abstract
Introduction: Proteins are being hydrolyzed to generate various properties such as antioxidant activity and nutritional values. Enzymatic hydrolysis is carried out in milder condition and is more controllable. The produced protein hydrolysates’ properties are dependent to the hydrolysis condition. ...
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Introduction: Proteins are being hydrolyzed to generate various properties such as antioxidant activity and nutritional values. Enzymatic hydrolysis is carried out in milder condition and is more controllable. The produced protein hydrolysates’ properties are dependent to the hydrolysis condition. So by optimizing the hydrolysis conditions, proteins with higher antioxidant abilities are achieved. Response surface method is a statistical way to optimize and model the process more efficiently. The aim of present study was to optimize and model the hydrolysis condition to produce and antioxidant protein hydrolysate with high nutritional value from Cajanus cajan by pepsin. Materials and methods: First, Cajanus cajan’s proteins solubility was measured. After reaching the pHs with the most and least solubility, protein extraction was carries out by using NaOH and HCl. Enzyme concentration (1, 2, 3%), temperature (30, 35, 40 °C) and time (2, 3.5, 5 h) as independent variables were given to the Design Expert software and protein hydrolysis was done in a shaker incubator according to the 20 treatments suggested by the software. 1, 1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydroxyl radical scavenging activity, Reducing power and total antioxidant activity were measured as dependent variables. Antioxidant assays were modeled by the software and the optimum condition was evaluated. The obtained optimum condition was validated by repeating the antioxidant assays for the protein hydrolysate produced in the optimum condition. The amino acid profile of the protein hydrolysate was measured using HPLC-MS and chemical score was measures. Then, the molecular weight distribution of the protein concentrate and protein hydrolysate was evaluated by FPLC. Chemical composition of the samples was also measured. Results & discussion: The optimum condition for achieving antioxidant protein hydrolysate was enzyme concentration 2.15%, temperature 39.99 °C and time 4.52 h. Model validation results for this point were including DPPH scavenging activity 58.49%, reducing power 0.31 nm, hydroxyl radical scavenging activity 38.2% and total antioxidant capacity 0.63 nm. The protein concentrate consisted of 215.84 mg/g hydrophobic and 57.04 mg/g of them were aromatic amino acids. These amino acids are responsible for antioxidant activity of the protein hydrolysates. Chemical scores for essential amino acids were good. Most of the peptides in the protein hydrolysate had molecular weights below 10 kD that is considered to have antioxidant activities. Hydrolysis also increased the protein and ash content while fat and water content decreased compared to the Cajanus cajan’s flour and protein concentrate. Results showed that Cajanus cajan’s protein hydrolysate can be a good source of antioxidants and play a positive role in human nutrition.
Marjaneh Alinejhad; Bahareh Shabanpour; Reza Safari; Mozhgan Alinejhad; Hassan Nasrollahzadeh Saravi
Abstract
The objective of this study was to produce fish peptone from tuna (Thunnus tonggol) viscera, by Alcalase. Response Surface Methodology (RSM) was employed for optimizing the temperature and pH. Hydrolysis was done in different tempratures (50-65˚C) , pH (8-8. 5) and selected 13 treatments. Samples with ...
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The objective of this study was to produce fish peptone from tuna (Thunnus tonggol) viscera, by Alcalase. Response Surface Methodology (RSM) was employed for optimizing the temperature and pH. Hydrolysis was done in different tempratures (50-65˚C) , pH (8-8. 5) and selected 13 treatments. Samples with higher value of protein were used instead of the standard peptones which applied in commercial media for Listeria monocytogenes. Based on the three-dimensional graphs, the optimum condition for temperature and pH were determined to be 50˚C and 8. 5 respectively. The results showed that the highest (76. 89 g/l) and the lowest (38. 54 g/l) rates of protein content were related to pH 8 at 57˚C and pH 8 at 50˚C. Maximum bacterial growth rate was related to pH 8 at 65˚C. Results also showed that tuna (Thunnus tonggol) viscera can be used as low cost nitrogen sources for Listeria monocytogenes growth media.
