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Multi-bioactive potential of a rye protein isolate hydrolysate by enzymatic processes
1 , 1 , 2 , 1 , 1 , 1 , 3 , * 4
1  Área Académica de Química. Universidad Autónoma del Estado de Hidalgo. Ciudad del Conocimiento. Carretera Pachuca-Tulancingo km 4.5 Colonia Carboneras. CP. 42184. Mineral de la Reforma, Hidalgo, México.
2  Departamento de Biotecnología. Universidad Autónoma Metropolitana, Unidad Iztapalapa. División de Ciencias Biológicas y de la Salud. Av. San Rafael Atlixco 186 CP. 09340, Ciudad de México, México.
3  Laboratorio de Biotecnología de Hongos Comestibles, Funcionales y Medicinales. Colegio de Postgraduados. Carretera México-Puebla km 125.5, C.P. 72760. Santiago Momoxpan, Puebla, México.
4  Departamento de Biotecnología. Universidad Autónoma Metropolitana, Unidad Iztapalapa. División de Ciencias Biológicas y de la Salud. Av. San Rafael Atlixco 186 CP. 09340, Ciudad de México, México. Área Académica de Química. Universidad Autónoma del Estad
Academic Editor: Antonello Santini

Abstract:

Nowadays, the interest in vegetable proteins has increased due to climate change. Rye has been considered as future food because it can grow during hostile wheater and contains several bioactive compounds. Thus, this work aims to determine the multi-bioactive potential of rye hydrolysates obtained with alcalase and flavourzyme. First, a protein isolate was obtained from whole grain rye, milling, and sieving through 297 µm mesh to get rye flour, which passed through alkaline and acid treatment for protein separation. Isolated protein was lyophilized at -54°C and 0.110 mbar for 48 h and was submitted to the total protein determination by the Kjeldahl method. Enzymatic hydrolysis was performed at 60°C and 130 rpm using rye protein suspensions at 10% (w/v) in phosphates buffer (0.1 M, pH=7.5) and adding both enzymes in a mass ratio of 100:2.5 (protein: enzyme). Sampling times considered were 0, 4, and 8 h, where supernatants to be analyzed were obtained after enzyme inactivation in boiling water for 10 min and centrifugation at 10,000 rpm at 4°C for 10 min. Spectrophotometric methods were applied to determine hydrolysis degree, radical scavenging capacity, and ACE and DPPIV inhibition by trinitrobenzene sulfonic acid method, DPPH test, hippuric acid determination, and p-nitroanilide release, respectively. The protein content found in the isolate was 51.06±1.15%, less than that reported in the optimized methodology (63-68%) for rye flours obtained by jet milling used as a reference. In the case of the hydrolysis produced by each enzyme, flavourzyme generated fewer free amino groups (2974.15±275.40 mg/L) at the eight hours of the process compared with the alcalase application (5481.40±409.43 mg/L). In this sense, flavourzyme showed a significative hydrolysis increase (p<0.05) between 0 and 4 h but was statistically constant until 8 h, while alcalase showed significative increases (p<0.05) in each time sampling. For bioactivities, the antioxidant capacity increased each time for both enzymes, achieving a maximum activity of 34.77±0.59% and 78.58±1.04% at 8 h for the flavourzyme and alcalase systems, respectively. Regarding ACE and DPPIV inhibition, flavourzyme maintained a similar behavior to that found in free amino groups, where both bioactivities were statistically constants between 4 and 8 h, reaching its maximum antihypertensive capacity (86.15±1.15%) at 8 h and antidiabetic activity (40.62±2.61%) at 4 h. In the same context, the ACE inhibition from alcalase hydrolysates increased from 81.87±4.9% at 0 h to 86.76±2.02% at 8 h. Still, the statistical analysis showed no significant differences. For DPPIV inhibition, alcalase hydrolysate showed statistical differences only between the 0 and 4 h (p<0.05) with inhibition of 63.70±1.27% at this last time. Finally, both enzymatic processes showed a promising multi-bioactivity potential, but the alcalase systems' results are better, especially for antioxidant and antidiabetic capacity.

Keywords: rye protein; enzymatic hydrolysis; multifunctionality

 
 
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