Environmental potential of increased human consumption of grain legumes - an LCA of food products

Examensarbete för masterexamen
Master Thesis
Abelmann, Anders
The environmental potential of an increased human consumption of grain legumes has been assessed using life cycle assessment (LCA). The product type that has been studied is a sausage, and three variants with different protein mix were included in the study: an animal product, an animal product with some vegetable protein, and a fully vegetarian product. The animal product is based on the “Hot Dog”, manufactured by Swedish Meats in Örebro, Sweden. Site-specific data for the sausage factory have been obtained from that facility. The other recipes have been created using recipe software. The functional unit in the study is “one kg sausage prepared and eaten in a household”. The protein content is equal for all three products. Two scenarios were set up; one where 10% of the animal protein was substituted for a vegetable alternative; and one where a fraction of the sausages consumed was substituted for a vegetable product. Two kinds of vegetable proteins have been studied, soy and pea. The reason for including soy is that no commercial pea product was found. Raw material and energy use, emissions, and waste data were collected for involved materials and processes. Chosen impact categories were: global warming potential (GWP), acidification, and eutrofication. The net energy input to each product was also calculated, as well as land use, expressed in m2. The environmental impact of vegetable protein production is less than 10% of the impact of animal protein production in all categories. The impact of pea protein is lower than the impact of soy protein. However, the substitution of 10% pea protein for animal protein in the hot dog only resulted in a decreased impact of about 5% due to a simultaneous change of recipe. To maintain certain characteristics of the Hot Dog the proportion of beef meat was increased in relation to pork. For the 100% vegetable soy sausage the impact decreased by between 55 and 87% compared to the Hot Dog, for the three impact categories eutrofication, acidification and GWP. A hot spot analysis reveals that the meat production accounts for the absolute largest share of the environmental impact, with home transports as runner-up. Looking at the sausage factory processes only, it can be seen that the peeling process (where a casing is removed from the sausage) accounts for a large impact, due to the steam production. The soy recipe is hypothetical in that it is constructed using a recipe software, due to that no manufacturer was willing to participate with a vegetable recipe. Thus, the calculations of the environmental impact from the soy product are uncertain, apart from the impact of the soy protein. Also, the sensory properties are unknown. It is more environmentally efficient to use vegetables as a primary protein source, not to feed animals but to produce it for human consumption. The future potential of vegetable protein relies much on the marketing and acceptance of new products like the partially vegetable sausage that is presented in scenario 1.
Miljöteknik , Environmental engineering
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