By Prof. C. Hanny Wijaya
Department of Food Science and Technology, Bogor
Maria Dewi P.T. Gunawan-Puteri
Department of Food Technology,
Swiss German University
(UMAMI INDONESIA | Edisi 3 Vol III 2015)
Indonesia is blessed with the combination of abundant natural sources
incorporated to its rich cultural heritage. Tempe is one of Indonesian local
product that went and stays global. Tempe and its derived products have
been known and consumed in all over Indonesian nation and trend for its
consumption abroad are increasing rapidly due to its superior nutrition
and functionalities. The utilization of tempeh has even developed more
than just a food. Tempeh application in cosmetic and drug production
has been reported recently.
Fresh tempe utilization was limited due to its short shelf life. After ripening, fresh tempe lasts for about 1 day in room temperature. In hot and humid area, like many places in Indonesia, the shelf life might even be shorter. In addition to develop many tempe products that will extend its shelf life such as tempe crackers and so on, our ancestor also develop utilization method for overripe tempe. Have you heard about “tempe semangit” or “tempe bosok”?
What is tempe semangit?
“Tempe semangit” as well as “tempe bosok” are over fermented tempe which the mold no longer survive and bacterial fermentation takes over (Gunawan-Puteri at al, 2013). “Tempe semangit” is also a term used for over-fermented tempe with pungent odor and darkened appearance commonly used in Javanese cuisine as condiment (Figure 1). These overripe tempes have been traditionally utilized as seasoning in Javanese cuisine such as in “lodeh”,”sambel goreng”,”gudeg”, etc (Yudianto, 1997). These overripe tempes have also been utilized as main ingredient in East Java typical cuisine like “sambal tumpang” or a Central Java snack called “menjeng” (Gunawan-Puteri et al, 2014).
What is the difference between “tempe semangit” and “tempe bosok”? According to Handoyo and Morita (2006), based on the period of fermentation, tempe known as “tempe semangit” is further fermented 48 hours after ripe, while “tempe bosok” is further 72 hours fermented. “Tempe semangit“ shows brownish colour with a pungent odour and soft texture compared to the white compact cake of mature tempe. The name ‘semangit’ might be come from a Javanese word ‘sangit’ which has meaning of pungent odour of hydrolyzed fat and or protein. In the Javanese society, “tempe semangit” usually has been fermented for 2-3 days more than the normal fresh tempe while “tempe bosok” is 4-5 days more. A little bit different with the term used by Handoyo and Morita (2006).
“Tempe Semangit” as Natural Source of Umami Flavor
A survey by Yudianto (1997) showed that majority of respondents know these type of tempe due to their roles as flavor enhanceras well as flavoring by imparting the flavor of the dishes with their unique distinct aroma and favorable taste which was later known as their “umami power”. This common local knowledge recently has been scientifically backed up by several studies as shown in Table 1.
Table 1 show the study of Handoyo and Morita (2006) reporting on the composition of free amino acids of fermented soybean (tempeh) by R.oligosporus at 24, 48, and 72 h of fermentation period. Mold growth have been associated with the protein digestión into free amino acid. Increase in the free amino acid contribute to the superior digestibility of tempe and the formation of tempe unique flavor.
The study of Rahayu et al (2013) which attempted to characterize the taste-active compounds in water soluble extracts (WSEs) of overripe tempe also showed that the water soluble extract of the overripe tempe containing umami and bitter taste free amino acids at relatively high concentrations. If we used the terminology of Handoyo and Morita (2005), then the “tempe bosok” will contribute more umami taste than “tempe semangit”since the WSE from 72 hours over-fermentation has umami taste activity value higher than bitter taste activity, exhibiting the highest umami taste dilution factor. However, based on the community knowledge the 72 hours (3 days) overripe tempe is still categorized as “tempe semangit”. There are still a lot of interesting phenomena that can be observed.
Utilization of tempe semangit as natural umami ingredient
Tempe fermentation produces flavor, nutritional and functional compounds. Extending tempe fermentation increases volatile compounds that contribute to the unique taste of overripe tempe. Increasing glutamic acid composition and also the intensity of perceived taste and aroma of overripe tempe showed their potencies as fermented soybean seasoning. Utilization of “tempe semangit” as seasoning has been known for centuries in Javanese culture. The hurdles of its wider utilization is the short shelf-life. Traditional preservation of overripe tempe is usually done by sundrying or roasting.
The growing importance of over-ripe tempe as food seasoning and ingredient has lead to investigation to prolong the shelf life and increase the convenience of its use (Yudianto, 1996). Yudianto (1996) developed processing methods of tempe bosok as overripe tempe flour. The ready-to-use flour resulted in longer shelf life. Drying treatment show the capability to reduce the number of microorganism in the samples. Hassanein et al (2014) reported that powdered overripe tempe has lower total and pathogenic microbial count due to the drying process and also due to the activity of lactic acid bacteria, that survived drying process, to reduce the number of microorganism.
As flour, overripe tempe saves storage space and allows further processing for ingredients development. Gunawan-Puteri et al (2015) reported that freeze drying could maintain the original aroma of tempe semangit while oven drying of increased color intensity of the samples as well as changing the aroma charateristic. The drying process altered the amount of glutamic acid content associated with umami taste, along with alteration of arginine and proline content associated with the bitter taste and alanine, which is often associated with sweet taste, while the rest of amino acid content tend to remain similar. Oven –dried overripe and fresh tempeh powders showed higher glutamic acid content (14.5 %, 15.9 %) comparing to the freeze–dried tempeh powders (13.9 %; 13.9 %) and the original tempeh cakes (12.8 %, 12.6%), respectively.
In general, the enzymatic hydrolysis of proteins during fermentation gives a bitter taste but some peptides can produce savory or umami taste, such as peptides were isolated and characterized from the cheese, soy sauce, miso and of course tempe. The existence of Glutamic acid as dominant amino acid in overripe tempe create potential opening for its development as a basic ingredient for seasoning production and contribute to the maintenance of our natural heritage and local wisdom.
As mentioned in above facts, “tempe semangit” is a Indonesian heritage that are potential to be further developed as seasoning product based on its natural umami benefits. Local wisdom of this overripe tempe utilization may get along well with recent market trend demanding for more natural ingredients. The natural availability of the umami power will provide added value and benefits of tempe semangit. The long history utilization and local experiences might reduce the anxiety of health issue. Potencies of “tempe semangit” shall be further explored to help this kind of tempe catch the same train of fresh tempe in term of preparation, application, and the following consumption popularity.
Handoyo T and Morita N. 2006. Structural and functional properties of fermented soybean (tempeh) by using Rhizopus oligosporus. International Journal of Food Properties 9, 347-355.
Hassanein, T.R., E.K. Prabawati, and M. D. P. T. Gunawan-Puteri. 2014. Development of Overripe Tempeh as Seasoning Material. The 3rd International Symposium on
Processing of Foods, Vegetable, and Fruits (ISPFVF 2014).
Gunawan-Puteri, M. D. P. T., T. R. Hassanein, E. K. Prabawati, C.H. Wijaya, and A. N. Mutukumira. 2014. Solid State Fermentation for Flavor Production in Fermented Soybean Products. International Conference on Natural Sciences (ICONS) 2014.
Yudianto M. 1997. Pemilihan kondisi proses pembuatan dan karakterisasi tepung “tempebosok”. [Dissertation] Yogyakarta: Jurusan Teknologi Pengolahan Hasil Pertanian Fakultas Teknologi Pertanian Universitas Gadjah Mada.