The taste of sustainable pork
Is it possible to discern the taste of sustainably fed pigs? The Danish research project, SuperGrassPork, spearheaded by SEGES, studied whether different levels of biorefined grass protein in feed mixes impact a pig’s growth and meat quality.
Feed optimisation has always been a major aspect of food production. A reduced climate footprint is also important in Danish food production. Consequently, the agricultural sector has endeavoured to identify where production optimisation and the climate go hand in hand. SEGES, together with livestock experts from Aarhus University, have translated this philosophy into reality in the Danish research project, SuperGrass Pork.
The project involves a trial comprising 48 pigs, divided into four groups. Each group is fed four different levels of grass protein - 0%, 5%, 10% and 15% - extracted from locally grown clover fields in Denmark. The concept behind the project is to analyse the potential for finding more sustainable alternatives to imported soya which accounts for a large proportion of pig feed.
Challenges and prejudices
As pigs cannot convert the protein from the grass directly from fields, the grass undergoes a biorefining process whereby protein from clover grass is extracted and used in feed that can be digested in a pig’s stomach. In practice, this process requires more local biorefining plants in Denmark, which is why major financial investment is needed.
If protein from grass is to replace imported soya, it cannot adversely impact the pigs’ growth or the quality of the meat. There is also a risk that the strength of the grass protein impacts the colour, taste and structure of the meat and fat. For these reasons, the project leader of SuperGrass Pork, Erik Fog, was particularly interested in the results of the project:
"The SuperGrassPork project studies the technique, quality and economics of grass protein,” explains Erik Fog, who is also an adviser with SEGES Organics and Innovation.
The outcome of the SuperGrassPork project has been encouraging. The pigs displayed a good appetite despite feed mixes with a high content of grass protein. Daily gain and feed conversion were identical with or without added grass protein.
"We can see that the pigs thrive well on grass protein and clearly enjoy it. They show an eagerness to consume the feed even when a relatively large portion of grass protein has been added. Even the pigs with the highest test rate of 15% grass protein mix are doing really well,” Fog explains.
Taste of grass protein in roast pork
The GreenPork project under the auspices of Aarhus University tested meat from the SuperGrass project for eating quality. A panel with particularly refined taste buds took part in a blind tasting where they compared the appearance, smell, taste and consistency of the meat from pigs with and without grass protein in their feed.
The results were positive. Overall, the panel decided that there were only minor differences in the meat from the two groups of differently fed pigs. Of the many characteristics that were tested, such as sourness, sweetness and bitterness, cooking aroma, juiciness, tenderness, etc. only a certain difference was found in the meat’s fibre structure, where meat from the pigs fed with a large amount of grass protein has a stronger fibre structure. The meat was also darker and less pink.
Same taste nuances
At a tasting event in Herning in Jutland, members of the general public and pig farmers took part in another blind tasting. The results were identical with those reached by the professional taste panel. The taste and aroma of the pork were unaffected regardless of whether the pigs were given 0% or 15% grass protein mix.
The positive results from the Danish research project are highly significant for the sustainable development of agriculture. Feed mix with 15% grass protein consists exclusively of Danish locally harvested raw materials. Biorefined grass protein for finishers contributes to the green transition of agricultural production, but without compromising on consumers’ expectations as regards the end product. Although the pig feed is greener, the taste, structure and colour of the meat remain the same.