Effects of canola proteins and hydrolysates on adipogenic differentiation of C3H10T/2 mesenchymal stem cells.

This study assessed the ability of canola protein isolate (CPI) and enzymatic hydrolysates (CPHs) to inhibit adipogenic differentiation of C3H10T1/2 murine mesenchymal stem cells in vitro. Cell viability was maintained at concentrations of 60 µg/ml of sample. Cells treated with Alcalase hydrolysate demonstrated a higher reduction in anti-adipogenic differentiation through quantitation by oil-red O staining. qPCR analysis showed that CPI and CPH-treated cells significantly inhibited PPARγ expression, a key transcription factor involved in adipocyte differentiation, as evident in an ∼ 60-80% fold reduction of PPARγ mRNA. Immunofluorescence staining for PPARγ protein also showed a reduced expression in some treated cells when compared to differentiated untreated cells. The 50% inhibition concentration (IC50) of CPI, CPHs and their membrane ultrafiltration fractions on pancreatic lipase (PL) activity ranged between 0.75 and 2.5 mg/ml, (p < 0.05) for the hydrolysed and unhydrolysed samples. These findings demonstrate that CPI and CPHs contain bioactive components which can modulate in vitro adipocyte differentiation.

Antioxidant properties of Australian canola meal protein hydrolysates.

Antioxidant activities of canola protein hydrolysates (CPHs) and peptide fractions prepared using five proteases and ultrafiltration membranes (1, 3, 5, and 10kDa) were investigated. CPHs had similar and adequate quantities of essential amino acids. The effective concentration that scavenged 50% (EC50) of the ABTS(+) was greatest for the <1kDa pancreatin fraction at 10.1µg/ml. CPHs and peptide fractions scavenged DPPH(+) with most of the EC50 values being <1.0mg/ml. Scavenging of superoxide radical was generally weak, except for the <1kDa pepsin peptide fraction that had a value of 51%. All CPHs inhibited linoleic acid oxidation with greater efficiency observed for pepsin hydrolysates. The oxygen radical absorbance capacity of Alcalase, chymotrypsin and pepsin hydrolysates was found to be better than that of glutathione (GSH) (p<0.05). These results show that CPHs have the potential to be used as bioactive ingredients in the formulation of functional foods against oxidative stress.

Biophenols and antioxidant properties of Australian canola meal.

During the extraction of canola oil, large quantities of meal are produced. Extracting biophenols from Australian canola meal (ACM) adds value to an otherwise low-value agro-industrial byproduct. This study examined the biophenol content and the antioxidant activity of ACM, the impact of extraction conditions, and varietal differences. Sinapine was the principal biophenol in ACM. In crude and hydrolyzed extracts, 31 compounds were identified: 2 dihexosides, 2 organic acids, 4 glucosinolates, 17 sinapic acid derivatives, 2 cyclic spermidine alkaloids, caffeic acid and its dihexoside, kaempferol, and its C-glucoside. ACM showed significant free radical scavenging activity in DPPH(•) and ABTS(•+) assays. Sinapine was the chief contributor to ACM antioxidant activity, whereas kaempferol sinapoyl triglucoside isomer was the most potent antioxidant. Biophenol content ranged between 12.8 and 15.4 mg GAE/g DW. Differences among studied cultivars were generally quantitative. The Tarcoola cultivar showed the highest biophenol content and antioxidant activity.

Canola proteins for human consumption: extraction, profile, and functional properties.

Canola protein isolate has been suggested as an alternative to other proteins for human food use due to a balanced amino acid profile and potential functional properties such as emulsifying, foaming, and gelling abilities. This is, therefore, a review of the studies on the utilization of canola protein in human food, comprising the extraction processes for protein isolates and fractions, the molecular character of the extracted proteins, as well as their food functional properties. A majority of studies were based on proteins extracted from the meal using alkaline solution, presumably due to its high nitrogen yield, followed by those utilizing salt extraction combined with ultrafiltration. Characteristics of canola and its predecessor rapeseed protein fractions such as nitrogen yield, molecular weight profile, isoelectric point, solubility, and thermal properties have been reported and were found to be largely related to the extraction methods. However, very little research has been carried out on the hydrophobicity and structure profiles of the protein extracts that are highly relevant to a proper understanding of food functional properties. Alkaline extracts were generally not very suitable as functional ingredients and contradictory results about many of the measured properties of canola proteins, especially their emulsification tendencies, have also been documented. Further research into improved extraction methods is recommended, as is a more systematic approach to the measurement of desired food functional properties for valid comparison between studies.