Protein hydrolysates of Moringa oleifera seed: Antioxidant and antihyperglycaemic potential as ingredient for the management of type-2 diabetes.

New plant proteins with high nutritional quality and biological properties are actively searched worldwide. Moringa oleifera seed protein isolate was prepared from defatted flour and hydrolyzed using four proteases namely trypsin, pepsin, Alcalase, and thermolysin. Then, antioxidant activity and cellular glucose uptake properties of the hydrolysates were assessed. A high degree of hydrolysis was obtained for hydrolysate prepared using trypsin (60.07%), followed by pepsin (57.14%), Alcalase (50.68%), and thermolysin (45.45%). Thermolysin hydrolysate was the most antioxidant efficient (IC50 0.15 and 0.74 mg/mL for 2,2'-azino-bis(acide 3-ethylbenzothiazoline-6-sulfonique) diammonium salt (ABTS) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, respectively). Trypsin hydrolysate stimulated high glucose uptake by yeast cells (12.34-35.28%). In the absence of insulin, Alcalase hydrolysate was the most efficient for glucose uptake by the muscle, with the rate ranging from 22.03% to 29.93% after 30 min, then from 29.55% to 34.6% after 60 min. The four hydrolysates improved glucose uptake by the muscle in the presence of insulin with the rate ranging from 46.88% to 58.03% after 30 min, and from 50% to 58.18% after 60 min. Therefore, Moringa oleifera seed proteins could be used to prepare peptides as components of functional foods for the management of type-2 diabetes.

Effect of heat treatment on the structure, functional properties and composition of Moringa oleifera seed proteins.

Knowledge on how food processing conditions and protein composition can modulate individual or food matrix protein functionality is crucial for designing new protein ingredients. In this regard, we investigated how heat treatment and protein composition influence physicochemical and functional properties of Moringa oleifera seed protein isolate. Results showed that changes in processing temperature induced modifications in the conformation affecting the hydrophobic core of proteins. Protein isolate was more soluble at room temperature whereas prolamin fraction presented high solubility at 70 °C. Glutelin showed higher emulsifying properties at all temperatures. Protein composition also significantly affected physicochemical and functional properties of protein isolate. Increasing soluble glutelin enhanced solubility while increasing albumin, globulin and glutelin decreased hydrophobicity of the isolate. Likewise, increasing soluble globulin improved emulsifying capacity, and emulsion stability of the isolate was negatively affected by increase in albumin and glutelin. These findings could enhance application of Moringa oleifera protein in food formulations.

Influence of pH and temperature on the physicochemical and functional properties of Bambara bean protein isolate.

Bambara bean is a rich low-cost protein source and a functional ingredient in the food industry. We investigated the effects of temperature and different pH on the physicochemical and functional properties of Bambara bean protein isolate. Vicilin was the major protein of Bambara bean as revealed by SDS PAGE analysis. The emulsifying capacity of protein isolate was highest at 80 °C, pH 9 while emulsion stability was highest at pH 4. Generally, increase in temperature decreased protein solubility at pH 4 and 7, while increase was observed at pH 9 and 100 °C. The hydrophobicity of isolate was highest at pH 4 and lowest at pH 9, regardless of temperature. Protein isolate possessed highly compact ß-sheet and α-helix secondary structures in proportions greater than 75% (at pH 9 and 50 °C). Increase in temperature generally promoted protein rearrangement and partial unfolding. Protein secondary structure and surface hydrophobicity can predict food functionality, directly affecting protein behavior during formulation and long-term storage. This study clearly demonstrated the potential of exploiting pulse protein isolates as nutritional and functional ingredients through temperature and pH control.