نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانشجوی دکتری گروه علوم و مهندسی صنایع غذایی، واحد آزادشهر، دانشگاه آزاد اسلامی، آزادشهر، ایران
2 دانشیار گروه علوم و مهندسی صنایع غذایی، واحد آزاد شهر، دانشگاه آزاد اسلامی، آزادشهر، ایران
3 استادیار گروه علوم و مهندسی صنایع غذایی، واحد آزاد شهر، دانشگاه آزاد اسلامی، آزادشهر، ایران
4 استادیار گروه کشاورزی و دامپروری، واحد آزاد شهر، دانشگاه آزاد اسلامی، آزادشهر، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective: Wheat germ, a primary by-product of the wheat milling industry, contains proteins with amino acid sequences that possess potential biological activities, making them suitable candidates for the production of bioactive peptides. The present study aimed to evaluate the enzymatic hydrolysis of wheat germ protein using three distinct enzymes—alcalase, trypsin, and pepsin—under both conventional and ultrasound-assisted conditions, in order to obtain protein hydrolysates with enhanced antioxidant capacity.
Materials and Methods: Protein isolate was initially extracted from defatted wheat germ flour. A 5% (w/v) protein solution was prepared and subjected to continuous stirring, followed by ultrasound pretreatment at 160 W for 5 minutes prior to enzyme addition. The pH of the reaction mixture was adjusted to the optimal value for each enzyme, and hydrolysis was carried out at an enzyme-to-substrate ratio of 1% (w/w) for varying durations ranging from 30 to 210 minutes at 30-minute intervals, at the respective optimum temperatures for each enzyme, both with and without ultrasound pretreatment. Upon completion of the hydrolysis period, the enzymes were inactivated, and the resultant hydrolysates were freeze-dried to obtain powdered samples. The antioxidant properties of the hydrolysates were subsequently evaluated through multiple assays, including iron-chelating activity, DPPH radical scavenging activity, total antioxidant capacity, and ferric ion (Fe³⁺) reducing power.
Results: The findings revealed that for all three enzymatic treatments, the percentage of iron chelation, DPPH radical scavenging activity, total antioxidant capacity, and ferric reducing power initially increased and subsequently decreased with prolonged hydrolysis time. For each assay, a maximum value was observed at a specific hydrolysis duration. Notably, the application of ultrasound pretreatment not only reduced the time required to achieve maximum antioxidant activity but also significantly enhanced the maximal values obtained. Among all treatments, the highest antioxidant activities were recorded for the alcalase-generated hydrolysate subjected to ultrasound pretreatment for 90 minutes, yielding an iron-chelating capacity of 72.6%, DPPH radical scavenging activity of 88.7%, total antioxidant capacity of 1.55 (absorbance at 695 nm), and ferric reducing power of 1.68 (absorbance at 700 nm).
Conclusion: The ultrasound-pretreated hydrolyzed wheat germ protein exhibited considerable antioxidant potential, which can be attributed to the cavitation phenomenon. This mechanical effect facilitates the disruption of complex protein structures, thereby increasing enzyme accessibility to cleavage sites. Furthermore, ultrasound pretreatment effectively shortens the optimal hydrolysis time for achieving maximum antioxidant capacity in the final product. Consequently, such hydrolysates hold promise as functional additives for incorporation into food products.
کلیدواژه‌ها [English]
)