Plant proteases for bioactive peptides release: A review.

Proteins are a potential source of health-promoting biomolecules with medical, nutraceutical, and food applications. Nowadays, bioactive peptides production, its isolation, characterization, and strategies for its delivery to target sites are a matter of intensive research. In vitro and in vivo studies regarding the bioactivity of peptides has generated strong evidence of their health benefits. Dairy proteins are considered the richest source of bioactive peptides, however proteins from animal and vegetable origin also have been shown to be important sources. Enzymatic hydrolysis has been the process most commonly used for bioactive peptide production. Most commercial enzymatic preparations frequently used are from animal (e.g., trypsin and pepsin) and microbial (e.g., Alcalase® and Neutrase®) sources. Although the use of plant proteases is still relatively limited to papain and bromelain from papaya and pineapple, respectively, the application of new plant proteases is increasing. This review presents the latest knowledge in the use and diversity of plant proteases for bioactive peptides release from food proteins including both available commercial plant proteases as well as new potential plant sources. Furthermore, the properties of peptides released by plant proteases and health benefits associated in the control of disorders such as hypertension, diabetes, obesity, and cancer are reviewed.

Effect of transglutaminase-induced cross-linking on gelation of myofibrillar/soy protein mixtures.

Microbial transglutaminase (MTGase)-catalyzed interaction and gelation of mixed myofibrillar (MPI)/soy (SPI) protein isolates were investigated at varying ionic strengths and MPI:SPI ratios, with or without SPI being preheated (80 °C). MTGase treatments in deionized water converted myosin heavy chain and actin into lower molecular-weight polypeptides, which gradually diminished as the ionic strength increased up to 0.6 M NaCl. A reduced intensity in the electrophoretic bands of soy proteins (7S and 11S except the basic subunits) was observed in all treatments, suggesting cross-linking with MPI. The enzyme treatment slightly increased the thermal transition (denaturation) temperatures of MPI/SPI but greatly enhanced (P<0.05) the elasticity of the mixed protein gels when compared with untreated samples, independent of incubation time.