Researchers from the Memorial University of Newfoundland and St. Francis Xavier University prepared canola protein hydrolysates using commercial enzymes, and report that, in addition to an improved water-holding capacity, the hydrolysates also had a high antioxidant activity.
"These results suggest that canola protein hydrolysates can be useful in terms of their functionality and as functional food ingredients and that their composition determines their functional properties and thus their potential application in the food and feed industries," wrote the researchers in the journal Food Chemistry.
The protein hydrolysates could offer the processed meat industry an alternative to phosphates, currently employed by the processed meat industry to maintain the "juiciness" of meat by binding water to the meat. Additives such as E450 (diphosphates), E451 (triphosphates) and E452 (polyphosphates) are commonly used.
However, reports have indicated that phosphates may pose health concerns to certain segments of the population, most notably people with kidney problems and diabetics.
The new study used two commercial enzymes - Alcalase and Flavourzyme - to prepare canola protein hydrolysates. They report that the type of enzyme employed in the process affected the antioxidant activity of the hydrolysate, with the hydrolysate prepared using Flavourzyme possessing a higher antioxidant activity than those prepared using a combination of the two enzymes, or Alcalase alone.
Antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity and reducing power.
When formulated into a model meat system, the researchers report that the hydrolysates enhanced the water-holding capacity and cooking yield. Again, Flavourzyme hydrolysates performed better than hydrolysates prepared using a combination of the enzymes, or Alcalase hydrolysates.
"The composition of enzymatically prepared protein hydrolysates dictates their functional properties and thus their potential application in the food and animal feed industries," state the researchers.
"Among the hydrolysates examined, those prepared using Flavourzyme were superior in terms of their antioxidant activity and water-holding capacity," they added.
The researchers noted that the hydrolysis pattern of Flavourzyme tended to produce low-molecular-weight protein hydrolysates, which may be behind the improved water-holding capacity observations.
"This is possibly because smaller fragments of peptides would be more hydrophilic," wrote lead author Nichole Cumby.
"However, composition of the peptides in each of the fractions may also play an important role.
"Further research should be conducted to examine the exact amino acid compositions of the hydrolysates so produced and their relationship to water-holding capacity of meat products," concluded Cumby and co-workers.
Source: Food Chemistry (Elsevier)
Volume 109, Issue 1, Pages 144-148
"Antioxidant activity and water-holding capacity of canola protein hydrolysates"
Authors: Nichole Cumby, Y. Zhong, M. Naczk, F. Shahidi