Encapsulating omega-3 fatty acids in milk proteins may protect the fish-derived ingredients from oxidation, and cover the ‘fishy’ flavour in cheese, says a new study.
Processed cheese with the emulsified omega-3 had lower levels of oxidation products, as well as no undesirable fishy off-flavour when used at a level of 5 grams per kg, according to findings published in Food Research International.
“At a given fish oil fortification levels, processed cheese samples fortified with encapsulated fish oil maintained a higher sensory quality versus ‘fishy’ off-flavour,” wrote the researchers from Massey University in New Zealand.
“This may suggest that an encapsulated fish oil emulsion is a useful carrier of omega-3 long-chain polyunsaturated fatty acids for fortifying processed cheeses with fish oil.”
Omega-3 fatty acids, most notably DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), have been linked to a wide-range of health benefits, including reduced risk of cardiovascular disease (CVD) and certain cancers, good development of a baby during pregnancy, joint health, and improved behaviour and mood.
Consumer awareness of these benefits is improving and the European market is reportedly growing at a rate of 24.3 per cent annually, according to Frost & Sullivan. The market could be worth $1.6bn by 2014, said F&S. This figure includes marine, algae and flaxseed sourced omega-3s.
In foods, most predictions are similarly ebullient. In a 2007 report, Packaged Facts estimated the US market was worth $2bn for foods and beverages bearing EPA, DHA and ALA either in combination or alone. Packaged Facts predicted the market would be worth $7bn by 2011.
One of the main challenges of putting fish oils into foods is the stability of the fatty acids and the flavour profile in order to avoid the undesirable ‘fishy’ taste and smell.
The new study looked at using a oil-in-water emulsion system to encapsulate fish oil. The researchers used the technique they developed previously and described in a patent cooperation treaty publication. The emulsion is stabilized by a pre-heated complex of sodium caseinate and whey protein, said the researchers.
Two types of processed cheese were prepared – one with the emulsified fish oil, and one with straight fish oil. Different levels of fish oil were used, ranging from none (control sample), and 5 to 40 grams per kg of cheese. The straight fish oil was found to be readily oxidized with an enhancement of the fishy off-flavour.
However, when formulated using the emulsified fish oil the levels of oxidation were reduced significantly. Sensory analysis also showed that “there was no significant difference in the sensory perception of samples containing a low level of fish oil (5 g per kg) and the control sample containing no fish oil”, said the researchers.
At the highest levels of 30 and 40 grams per kg the emulsified fish oil was detectable, and the sensory quality of the cheese was reduced.
“The 'fishy' flavour was detected at a lower level of fish oil addition in the samples in which fish oil was added directly during processing than in the samples with the addition of fish oil emulsion,” wrote the Massey researchers.
“This suggests that processed cheese could contain a higher level of fish oil and have an acceptable sensory perception when a fish oil emulsion is incorporated in the cheese,” they added.
Source: Food Research International
October 2009, Volume 42, Issue 8, Pages 1093-1098
“Evaluation of processed cheese fortified with fish oil emulsion”
Authors: A. Ye, J. Cui, A. Taneja, X. Zhu, H. Singh