Editing Tempeh (section)

==Preservation==
{{Cleanup section|date=July 2024|reason=This section contains is mostly technical information from a single source.}}
Freshly made, raw tempeh remains edible for a few days at room temperature. It is neither acidic nor does it contain significant amounts of [[alcohol (drug)|alcohol]]. It, however, does possess stronger resistance to [[lipid peroxidation]] than unfermented soybeans due to its [[antioxidant]] contents.<ref>[[Umm al-Qura University]], Mecca, Saudi Arabia [http://uqu.edu.sa/files2/tiny_mce/plugins/filemanager/files/4300301/Handbook_of_Fermented_Functional_Foods.pdf Handbook of Fermented Functional Foods] {{Webarchive|url=https://web.archive.org/web/20150714201123/http://uqu.edu.sa/files2/tiny_mce/plugins/filemanager/files/4300301/Handbook_of_Fermented_Functional_Foods.pdf |date=2015-07-14 }}</ref>

Cooked as {{Transliteration|jv|tempe kering}}, the deep-fried and seasoned bits of tempeh can last for a month or more and still be good to consume, if cooked correctly and stored properly in an air-tight jar. The deep-frying process removes the moisture, preventing further fermentation and deterioration, thus prolonging its shelf life.

=== Antimicrobial agents ===
''[[Rhizopus]]'' cultures responsible for the [[fermentation]] of tempeh from soybean produce natural, heat-stable [[Antimicrobial|antimicrobial agents]] against spoilage and disease-causing microorganisms, extending the [[shelf life]] of the fermented product through microbial antagonism. The mold is capable of inhibiting the growth of other fungi such as ''[[Aspergillus flavus]]'' and ''[[Aspergillus parasiticus]]'' by interfering with the accumulation of [[aflatoxin]] (especially [[aflatoxin B1]]), the [[mycotoxin]] of greatest concern. ''R. oligosporus'' has also been reported to produce four to five antibacterial substances during fermentation process. It produces [[Phenols|phenolic compounds]] against pathogenic bacteria such as ''[[Helicobacter pylori]]'' and an antibacterial protein has been identified with activities against ''[[Bacillus]]'' species (especially against ''[[Bacillus subtilis]]'' and ''[[Bacillus cereus]]''<ref>{{Cite journal|last1=Roubos-van den Hil|first1=P.J.|last2=Dalmas|first2=E.|last3=Nout|first3=M.J.R.|last4=Abee|first4=T.|date=2010|title=Soya bean tempe extracts show antibacterial activity against Bacillus cereus cells and spores|url=http://dx.doi.org/10.1111/j.1365-2672.2009.04637.x|journal=Journal of Applied Microbiology|volume=109|issue=1|pages=137–145|doi=10.1111/j.1365-2672.2009.04637.x|pmid=20002864|s2cid=44995408|issn=1364-5072|url-access=subscription}}</ref>), ''[[Staphylococcus aureus]]'', and ''[[Lactococcus lactis|Streptococcus cremoris]]''.

=== Non-refrigerated fresh tempeh ===
Tempeh can be sold and consumed fresh within 48 hours once removed from its incubator. It is commonly transported to the market in its incubation container (e.g. [[polyethylene]] bag, [[banana leaf]] wrapper, etc.) and placed in the shade. In areas with warmer climates, tempeh can be kept at room temperature for one to three days before it becomes overripe. In locations with more temperate temperatures, it can keep for one to four days but will usually need to be refrigerated to prevent spoilage.<ref name=":03" />

=== Refrigeration ===
Fresh refrigerated tempeh should be sealed in a labeled polyethylene bag and kept in temperatures below {{convert|40|F|C|order=flip}}. It can be kept at this temperature for three to five days and sometimes, even as long as a week. Storage life could be extended to two or three weeks if the tempeh is [[Blanching (cooking)|blanched]] or [[Steaming|steamed]] prior to refrigeration due to the inactivation of enzymes and destruction of bacteria.<ref name=":03" />

=== Freezing ===
[[Freezing]] is the preferred way to preserve tempeh due to its capability for wide distribution. Tempeh can be frozen whole or in slices, depending on preference. During the freezing process, whole tempeh is placed in its perforated wrapper whereas sliced tempeh is packaged in a labelled polyethylene bag prior to being sealed in an outer bag and then frozen immediately. This method will keep for months with only a small loss of texture and flavor.<ref name=":03" />

=== Blanching ===
Blanching tempeh by steaming or parboiling helps to extend the storage life by preventing bacterial growth, stopping mold growth and inactivating enzymes. Steaming appears to have a less negative effect than [[parboiling]] in terms of texture, flavor and nutritional value. Blanching is a great method for preserving tempeh prior to refrigeration, though not as beneficial for tempeh that is to be frozen.<ref name=":03" />

=== Dehydration ===

==== Air tray drying ====
Tempeh can be dried via the air tray drying method. Cubes of tempeh placed on steel, mesh bottom trays are dried by the circulating hot air dryer. After the product is finished, they can be cut into {{convert|1|in|cm|order=flip|adj=on|abbr=off}} squares at {{convert|200|F|C|order=flip|sigfig=1}} for 90 to 120 minutes in order to reduce moisture content to 2–4%. When placed in moisture proof [[Pliofilm]] bags, the tempeh has a shelf life of several months at room temperature. Although this is a convenient method that produces a shelf stable product without requirement of refrigeration, the process of hot air drying can cause a significant loss of nutritional content such as the soluble solids and [[nitrogen]] protein content.<ref name=":03" />

==== Sun drying ====
This preservation method is most economical out of all methods. The tempeh can be blanched prior to dehydration to preserve flavor and prolong shelf life. Tempeh is exposed to internal [[solar dryer]] temperature of {{convert|180-200|F|C|order=flip|sigfig=1}} in this method. A disadvantage of this method is that sunlight can destroy some of the [[vitamin B12]] of tempeh.<ref name=":03" />

==== Freeze-drying ====
This method is the most expensive out of all dehydration methods but provides the advantage of long stable shelf life at room temperature and an excellent retention of soluble nutrients (nitrogen protein and other solids). The product undergoes quick freeze at {{convert|50|F|C|order=flip}} and is then dried at a moderate temperature inside a strong [[vacuum]]. Due to the expensive nature of the equipment, the final product price is higher than tempeh preserved through other methods.<ref name=":03" />

==== Spray-drying ====
As this method is traditionally used for small particles, it is used to produce tempeh powder for products such as [[soup]]s, [[bread]]s, [[tortilla]]s, etc. However, this method can be expensive due to the bulky nature of the equipment.<ref name=":03" />

==== Deep-frying ====
This method produces ready to eat tempeh products. A culinary oil with a high [[smoke point]], such as [[rapeseed]], [[Soybean|soy]], [[safflower]], [[peanut]], or [[coconut]] oil, is heated to {{convert|350|F|C|order=flip|sigfig=2}} in the deep fryer. The tempeh is deep-fried until golden brown and crisp, and then cooled quickly in a sterile environment to be sealed in Pliofilm bags and stored in a cool, dry place. The shelf life of this product lasts around a week but can be extended if the tempeh is sun dried or oven dried prior to deep frying.<ref name=":03" />