Development of Tempeh on Swedish Legumes

Abstract

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.

Popular Abstract

The growing trend of replacing meat in the diet have made the food scientists explore a whole new word of innovative meat substitutes.
In a pilot hall in the cellar of “Kemicentrum” in Lund, a project to develop a meat substitute was recently finished after going on for half a year. The result? -A white, moldy, block of beans or peas, with an incredible taste.
An increasing amount of people are replacing meat in their diets. Soy-based products hold a huge share of this market with products such as tofu, tempeh, soy-meat and soy-bacon. Although soy usually has a smaller environmental impact than meat, there are environmental issues regarding soy as well. Two examples are rainforest devastation and global transportations.
In this project, the traditional Indonesian food “Tempeh” was taken as a role model in the development of a similar product using Swedish legumes instead of the usual soybeans. The idea was to reduce the environmental impact of an ever-growing soybean production and to increase the consumption of Swedish, locally produced crops.
Tempeh is produced by fermenting boiled legumes using the mold Rhizopus oligosporus. The mold attaches the legumes to one another and creates a sliceable, firm block of tempeh. The appearance of the tempeh is similar to that of French nougat, and the smell gives associations to bread and mushrooms. Tempeh is lovely when fried, and has a creamy, characteristic taste.
Because tempeh is fermented, there is obviously a growth of microorganisms. The project showed that apart from the intended growth of the mold used as starter culture, there were billions of other microorganisms growing in the tempeh. This is not ideal, but as with other traditional fermented foods: history, experience and science show that legume-based tempeh is safe for consumption. On top of that it is also claimed to have health beneficial effects.
Two types of tempeh were developed in this project, one with yellow peas, and one with brown beans. In the sensory evaluation performed, all volunteers considered both types of tempeh to be well tasting.
There is always a randomness in the outcome of tempeh due to the biological process, and thus, the biggest challenge of the project was to get a consistent, well standardized -product. Different production steps were altered, and the ones which gave the best results were all combined in the end. This was done in the struggle to make the best possible tempeh in regard to taste, consistency and appearance. The appearance of the two best tempeh can be seen in the picture below – please enjoy.

• author: Åström, Nils
• supervisor: Åsa Håkansson; Pamela Rosario Canaviri Paz
• organization: Food Technology and Nutrition (M.Sc.)
• course: KLGM10 20181
• year: 2018
• type: H2 - Master's Degree (Two Years)
• subject: Agriculture and Food Sciences; Technology and Engineering
• keywords: Product development, Process optimization, Food technology, Fermentation, Tempeh, Meat substitute, Vegan product, Swedish legumes, Livsmedelsteknologi
• language: English
• id: 8957725
• date added to LUP: 2019-04-10 16:27:39
• date last changed: 2019-04-10 16:27:39