Functional Properties of Guava Seed Glutelins

Abstract

Five guava seed glutelin extracts were obtained with different buffer solutions: Na(2)B(4)O(7) alone (Glut.Bo) or containing SDS (Glut. BoSDS), 2-mercaptoethanol (Glut.Bo2-ME), or a combination of both (Glut. BoSDS2-ME) and NaOH (Glut.Na). All borate buffer solutions were at pH 10. The higher yield of glutelins corresponded to the Glut. BoSDS extract (81.9% dry basis) and the lower to Glut.Bo (6.8%). The functional properties of the five guava seed glutelin extracts were determined. Glut. BoSDS, Glut. BoSDS2-ME, and Glut.Na showed high values for several properties, including surface hydrophobicity (7.7, 10.8, and 0.6, respectively), solubility at pH 10 (91.1, 77.9, and 96.7, respectively), water-holding capacity at pH 3.6 (1.7, 2.5, and 2.8, respectively), emulsifying activity index (pH 10; 503.5, 238.2, and 838.0, respectively), and foaming properties (pH 10; V(0) = 0.14, 0.25, and 0.19, respectively; V(max) = 6.1, 5.59, and 4.51, respectively; t(1/2) = 266, 255.3, and 94 s, respectively). These results suggest that the denaturing reagent (SDS or NaOH) during extraction conferred on the proteins a structure that facilitated the development of their functional properties.

Influence of pH on Structure and Function of Amaranth (Amaranthus hypochondriacus) Protein Isolates

“…Use of vegetable seed protein preparations as ingredients in the food industry (Bernardino-Nicanor et al 2005;Adebowale et al 2007) requires knowledge of the protein physicochemical and functional properties. Amaranth is an excellent potential source of proteins because its seeds have high protein content (14-18%, versus ±10% of commercial cereals) with a balanced proportion of essential amino acids (Teutonico and Knor 1985;Bresani 1989).…”

Linoleic acid‐rich guava seed oil: Safety and bioactivity

“…Family Myrtaceae) is an edible tropical fruit and a well‐known medicinal plant that has been widely used in traditional folk medicine (Gutierrez, Mitchell, & Solis, ; Morais‐Braga et al, ). Guava seeds are the by‐products of guava juice processing and are used for animal feeding; however, they are known to contain nutrients and dietary fiber (Bernardino‐Nicanor, Anon, Scilingo, & Davila‐Ortiz, ; Chang, Tan, Lok, Pakianathan, & Supramaniam, ; Michael, Salib, & Ishak, ; Nair, Nagar, & Gupta, ).…”

“…Methods (such as heating, boiling, and roasting) and agents (such as sodium dodecyl sulfate and acetone) have been used to extract nutrients from guava seeds, thereby obtaining proteins, glutelins, flavonoid glycosides, phenolic glycosides, and phenylethanoid glycosides (Bernardino‐Nicanor et al, ; Salib & Michael, ). Importantly, the seed extract exerts strong antioxidant, antilipid peroxidation, and antibacterial activities (Huang et al, ; Pelegrini et al, ).…”

Influence of heat denaturation and freezing–lyophilization on physicochemical and functional properties of quinoa protein isolate

“…Table shows that the water‐holding capacity increased twice (2.18–2.29 g H 2 0/g) in the two modified isolates in comparison with water‐holding retention of QPI (1.02 g H 2 0/g), while the oil retention capacity was 10 times higher in QPI‐FL (1.50 g oil/g sample) and approximately twice as high in QPI‐HD (0.39 g oil/g sample) compared to QPI (0.15 g oil/g sample). It is observed that these results were contrary to the solubility found in the samples; however, it has been reported that the solubility is not related to the water retention capacity of a material (Bernardino‐Nicanor, Añon, Schilingo, & Dávila‐Ortiz, ), since this depends among other factors on the electrostatic interaction between amino acids and water; however, both the water and oil retention capacity depend on the ability of the protein to imbibe water or oil in its matrix and retain it against gravitational force. The greater capacity of retention of water and oil retention of QPI‐FL was possibly due to modified proteins in addition to presenting polar groups on its surface that cause interactions with water molecules available on the surface (Abugoch et al, ) they also have a more porous surface structure that allows water molecules to have a greater accommodation on the surface.…”