نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانش آموخته کارشناسی ارشد مهندسی علوم و صنایع غذایی، گروه علوم و صنایع غذایی؛ دانشکده کشاورزی، آب، غذا و فراسودمندها؛ واحد اصفهان
2 دانشیار، گروه علوم و صنایع غذایی؛ دانشکده کشاورزی، آب، غذا و فراسودمندها؛ واحد اصفهان (خوراسگان)؛ دانشگاه آزاد اسلامی؛ اصفهان؛ ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective: Food security is one of the fundamental global challenges, and addressing protein deficiency in nutrition is especially critical in developing countries. Plant-based proteins have garnered significant attention due to their environmental sustainability and the reduction of dependence on animal sources. Extracting protein from plant by-products, such as oilseed meals, not only reduces resource waste but also minimizes environmental impacts. Hazelnut meal, as an agricultural by-product, can serve as a sustainable high-quality protein source. In this study, protein was extracted from hazelnut meal using ultrasound pretreatment, alkaline extraction, and acid precipitation. The functional properties of the extracted protein were evaluated to enhance its applicability in the food industry.
Materials and Methods: To extract protein from hazelnut meal, a defatting process was first carried out. Subsequently, a mixture of defatted hazelnut meal and deionized water was prepared and subjected to ultrasound pretreatment to facilitate protein release. The pH of the mixture was adjusted using sodium hydroxide solution based on the optimal values suggested by the experimental design software. After the initial centrifugation, the supernatant was collected and adjusted to the isoelectric point by adding hydrochloric acid solution. At this stage, a secondary centrifugation was performed, and the resulting precipitates were washed, neutralized, and dried using a freeze dryer. The experiments were conducted using the Response Surface Methodology (RSM). The independent variables in this study included alkaline pH (10 to 12), centrifugation temperature (4 to 24°C), ultrasound bath time (5 to 25 minutes), and temperature (20 to 40°C). The dependent variables were water and oil absorption capacities. The experimental design was performed using Design Expert software with a Central Composite Design (CCD), consisting of 38 different treatments with 6 replications at the central point and a significance level of 5%. To validate the model and compare the predicted results with the experimental data at the optimal point, the t-student test was used.
Results: Results of the Analysis of Variance for the dependent variables showed that the quadratic model was statistically significant (p < 0.05). The analysis indicated that increasing the ultrasound time up to 16 minutes initially decreased the water absorption capacity and then increased this parameter. Similarly, increasing the ultrasound temperature up to 26 °C led to an initial increase followed by a decrease in water absorption capacity. Moreover, increasing the pH from 10 to 12 resulted in a significant increase in water absorption capacity. According to the findings, increasing ultrasound time up to 20 minutes initially increased and then decreased the oil absorption capacity. Additionally, increasing the ultrasound temperature up to 36 °C resulted in an initial increase followed by a slight decrease in oil absorption capacity. Furthermore, increasing the pH up to 11.4 initially caused a decrease, followed by a slight increase in oil absorption capacity.
Conclusion: The results showed that ultrasonic pretreatment improved the water and oil absorption capacities of hazelnut meal protein. For numerical optimization, the values of the independent variables were adjusted within the defined range, and the dependent variables were evaluated with the aim of achieving the highest possible values. Under optimal conditions, the process involved an ultrasonic temperature of 23.840 °C, an ultrasonic time of 25 minutes, a centrifuge temperature of 4.001 °C, and a pH of 12. Under these conditions, the water holding capacity (1.481 grams of water per gram of protein) and oil absorption (3.739 grams of oil per gram of protein) were determined. All experiments were performed in triplicate. There was no significant difference between the predicted results by the model and the experimental values under optimal conditions. These findings confirm the accuracy and reliability of the proposed model.
کلیدواژهها [English]
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