Development of Tempeh on Swedish Legumes

Sammanfattning: The emerging market for meat substitutes has largely been filled with different types of soy products. Although soy usually has a lower environmental impact than meat, soy is not entirely unproblematic. Deforestation and global transportations are two negative effects of the increasing production of soybeans. One of these meat substitutes is tempeh: an Indonesian mold-fermented food usually made of soy. Tempeh can however be made with many types of legumes. In this thesis, the soybeans in tempeh have been replaced with Swedish grown yellow peas and brown beans. These Swedish legumes are not associated with the same environmental problems as soybeans. The aim was to develop a good tasting tempeh on Swedish legumes which could become commercially viable. To ensure this, objective quality parameters were investigated as well as the safety of the product. A sensory evaluation with 21 volunteers was also performed. To produce tempeh, eight process steps were established. The steps were: Washing, Soaking, Boiling, Drying, Peeling, Inoculation, Bag preparation, Incubation. A process optimization was executed, where the most important of those eight steps were optimized to observe the effect in the result. The idea was to optimize as many different parameters as possible and in the end combine the best ones to create the best possible tempeh regarding taste, looks and consistency. Two investigations were conducted to ensure the safety of the tempeh. The microbiological investigation showed that the tempeh contains loads of microorganisms other than the obvious mold. The cfu/g on VRBD (Enterobacteriaceae or other bile-tolerant Gram-negative bacteria) was >3'105 for yellow pea tempeh and 3.35'104 for brown bean tempeh. The bacteria have most probably originated from the starter culture. Those kinds of bacteria are generally indicators of bad food hygiene. When investigating a pea tempeh inoculated with Lactobacillus plantarum 299v, the cfu/g on VRBD was substantially smaller, indicating that the lactobacilli outcompeted the Enterobacteriaceae. The presence of lactobacilli could therefore be included in a safer, future version of the tempeh. The toxin investigation showed that the tempeh contained Ochratoxin A at levels of <1.0 μg/kg, Aflatoxin B1 at levels of <0.2μg/kg and Aflatoxin B2 at levels of <0.5μg/kg. These levels did not differ much from normal amounts found in legumes. Therefore, the tempeh made in this project do not contain dangerous amounts of these mycotoxins. The sensory analysis showed that there is a significant difference in taste between tempeh made on yellow peas and brown beans respectively compared to soy. The analysis also showed that tempeh on brown beans is as favorable as soybean tempeh and that tempeh of all three legumes was appreciated by all volunteers.