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 Amino Acid references 
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Joined: Wed Apr 02, 2014 6:44 pm
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Post Amino Acid references
A few free online sources have data on BSF amino acid profiles. Here is one study (see "Fig. 1a & 1b") to deduce certain ratios from: (2010) "A Novel Protein Source: Maggot Meal of the Black Soldier Fly ... in Broiler Feed."
It's focus is on how to reduce fish meal fed to chickens & determine if when substitute BSF larvae (maggot) if larval fat content makes a difference. Result was after 24 days the fish meal fed chicken only weighed ~1gram more than the full fat BSFL fed chicken.
free full text = http://feedtest.de/Publikationen/2010%2 ... 20meal.pdf


Fri Apr 25, 2014 5:38 pm
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Joined: Wed Apr 02, 2014 6:44 pm
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Post Re: Amino Acid references
Pre-pupae amino acid % are (see Table 3) elaborated in (2007) "Fly Prepupae as a Feedstuff for Rainbow Trout". Free full text =
http://forensicentomology.tamu.edu/pdf/ ... 202007.pdf


Fri Apr 25, 2014 5:52 pm
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Joined: Wed Apr 02, 2014 6:44 pm
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Post Re: Amino Acid references
Fermentation improves amino acid levels so I'll re-post/adapt what have written elsewhere under this heading. Developing countries outside the temperate zone without reliable electricity might have problems keeping temperature down for using immersion fermentation.... An alternative fermentation for those dealing with warm ambient temperatures could be rice bran fermentation; and by extrapolation other bran's for forming a fermentation medium. I have used a Japanese version of this method, although not yet with larvae, & it is not complicated to start up....Rice bran, called "nuka" in Japanese, is stir toasted in a pan until the color darkens fairly uniformly; but not scorched black. Then 10% of salt is mixed into the toasted rice bran; this proportion is by weight & more salt can be used if experience dictates.... Next moistening is done little by little, to bring the medium to the consistency of something akin to damp beach sand. I used a solution of water & beer (& some miso). Beer/miso provides some bacterial benefits which jump start the fermentation & so a "native" beer or an unpasteurized beer is ideal....The damp medium then gets something buried in it like an old cabbage leaf to inoculate with other bacteria, like Lactobacillus plantarum. Out in the "bush" any edible leaf could be substituted for cabbage & is likely to have L., plantarum on it as well. Another plant item to set into the bran medium is a whole hot pepper helps to keep bran medium reserved for good bacteria colonization....The fermentation vessel can be anything from a bucket to a clay crock. The ability to bury a rice bran fermentation in the ground will buffer outside temperature extremes & why I propose this for rural operations in hot climates....Before fermenting anything in a rice bran medium it must 1st develop it's micro-organisms. Use clean hands (don't put chemicals on hands that kill microbes) to mix the whole mass of medium at least 2 x daily for 4 weeks before inter any larvae for fermenting; leave the medium surface somewhat smoothed over but not mashed down.... Protect the surface with anything from paper, leaves, cloth of even a lid; it does not have to be air tight but best to keep dirt & insects from getting onto the medium. I've used a plastic tub & tight lid - but several times daily made sure to open the tub for hand mixing to introduced oxygen into the medium & never got anaerobic stagnation.... During the initial 4 weeks of culturing replace the leaves & whole pepper a few times. Some people put roasted eggshells in the medium as well for ion exchange; although I had no problems without any this may (?) prove to be a useful option when fermenting larvae....Once the rice bran medium is matured one doesn't need to keep adding cabbage leaves or whole hot peppers; the hot peppers (whole) could still buried in the bran with buried larvae & contribute flavor. After done with each of any daily hand stirrings make sure the larvae stay covered with bran medium....Of course we are placing only euthanized, not live larvae in the fermentation vessel. If larvae blanched in boiling water to surface clean & matted dry then a preliminary salt rub of the larval mass would be a good idea employ. Salt rubs usually allow a set aside period for the salt to draw out moisture & after salting then knock off as much salt as practical before burying in fermentation medium.... When finally take larvae out of the medium do not dispose of the medium. Just return medium clinging to larvae back to the bin for future use. Moisture control of the bran medium originally is easy, but over time water drawn out of the larvae can build up. In Japan a slab of Kombu seaweed is traditionally used to control moisture & some people say a Kelp frond works; just periodically replace the seaweed.... For operations out in the "bush" out of the seaweed market place just incline the fermentation vessel so water settles in a low point to one side, amass the bran medium to the far side & wick/swab up the visible excess water. If one's rustic method uses unglazed pots buried in the ground there is probably going to be a lot of natural wicking away of moisture going on anyway...When I used a lidded plastic rectangular container I wiped up the condensation on the underside of the lid & condensation all around the inner sides when opened up for hand mixing; then only needed periodic shunting of medium to one side for getting at bottom water to prevent anaerobic layer down below.... In terms of what type of fermentation is going on it is not strictly aerobic because for periods of hours every day low oxygen conditions down in the moist rice bran is good for those microbes that are not strictly oxygen lovers. Yet you need to expose medium to oxygen by hand mixing to keep enough of those oxygen loving microbes proliferating to avoid an imbalance of colonies. A short span of soggy rice bran medium will not spoil the bedding - just blend in more toasted bran & it's proportion of salt to overcome the saturation ....In Japanese the rice bran medium itself is called "nuka-doko" & what fermented in it is called "nuka-zuke"; English calls any nukazuke rice bran pickles.The time spent in fermentation need not be long to tenderize the "pickle" & yet the longer spent fermenting the more molecular changes occur in the "pickling".... Larvae will be tenderized for meal preparation within days of rice bran fermentation; after all they are edible to begin with . Longer fermentation creates an end product with more stable characteristics that then can resist environmental influences & thus more indicated if are storing a harvest of larvae....Since insects have fat & protein it can be instructive to recap some of the investigations into fish fermented in rice bran. One major factor of shelf life is to avoid oxidation of the fats (lipids) to avoid spoilage....The alteration of lipids in this medium is the result of hydrolysis being performed by bacterial enzymes & not exposure to oxygen. It is oxygen altered lipids (oxidized fats) that are a undesirable to ingest as well as what causes rancidity....Quote: "...both non-polar & polar lipids seemed to undergo enzymatic hydrolysis to release free fatty acids...polar lipids were phosphatidy-lcholine and phosphatidyl-ethanolamine ..." = no oxidative rancidity during processing and/or storage. See http://ci.nii.ac.jp/naid/130001545415/ ....As for the protein changes, again, it is enzymes acting over time producing changes. Some micro-organisms even are using the amino building blocks to fuel their metabolism, but the freed amino acids offer us various benefits....Anti-oxidants were found after sardines spent 6 month in the medium. Quote: "...increase of antioxidative activity during the ripening... attributable to the production of the antioxidative peptides from the meat....strongest antioxidative fraction... composed of peptides consisting of mainly Asp, Glu, Gly, & Lys....." See http://ci.nii.ac.jp/naid/130001545415/ ....Tenderization also occurs & should make for versatility in preparation. Quote: "...firmness... decreased gradually... fragility, increased during curing....myosin heavy chain (muscle)...smaller molecular size...caused by enzymes...." See http://ci.nii.ac.jp/naid/110003167974 ....The B vitamin group is also bacterial byproduct; with both folate & to a lesser degree B12 in the aged product. Lactobacillus plantarum, which is generally one of the predominant bacteria among the over 100 bacteria isolated from rice bran medium, produces folate. It seems L. plantarum can make so much folate it can inhibit itself. Quote: "...growth rate in L. plantarum was reduced ....by the enormous amount of gratuitously produced folate-related transcripts and proteins. See link= http://www.ncbi.nlm.nih.gov/pubmed/23132566 .... And for more on folate & L. plantarum a strain has been sequenced free full text link = http://www.pnas.org/content/100/4/1990.long .... For anyone looking for some of the names of bacteria acting in rice bran fermented fish & vitamin B12 see "Figure 3" in free full link = https://www.jstage.jst.go.jp/article/bb ... 20414/_pdf .... Now, the commercial & the homemade medium made from scratch appear to differ. A long lived rice bran "pickling' medium will undergo changes in it's microbial profile; & similarly inoculating a new bed by seeding it with an established medium improves the dynamic....Individual medium can vary greatly & this affects the sensory appeal of one fermented end product in comparison to another. Research done has named some of the bacteria after the place studied, but there is going to be native lactobacillus anywhere....Here is an example of how an inoculant can make a difference. If one were establishing an insect fermentation rural development project the implication is to maintain a laboratory production in order to distribute inoculant to the participants....With inoculation (or "old" medium) there can be a fast drop in pH (desirable) with an early lactate producing bacterial boost & at the same time Lactobacillus aceto-tolerans moves along more slowly for the 1st 3 weeks. This is fine, since the principal organic acids that are byproducts of the enzymatic activity in the rice bran fermentation are known to be lactic & acetic acid; the acetic acid profile is going to influence taste....With from scratch batches for the first 1.5 weeks there are more staphylococcus & bacilli growing until the local lactobacillus population booms enough to overcome other bacteria in medium niches. And the other drawback of fresh medium is for the 1st 3 weeks no L. aceto-tolerans colonization occurs & this can alter the flavor harmony due to unmodulated lactic acid present. See http://www.sciencedirect.com/science/ar ... 510005696/ .... Finally a bit more about salt. If keep salt at no more than 18% then the lactic acid bacteria desired can survive; higher than 18% & osmosis depletes internal moisture from them. At 10% salt there is maximum lactic acid bacteria activity & this should be fine for pre-pupating larvae whose gut have probably self-purged.... To ferment adult mobile insects, like crickets (minus legs/wings), whose gut may not be purged a higher salt content of 17.5% will allay their gut microbes from propagating in the rice bran medium. A consequence of 17.5% salt will be lower lactic acid bacteria getting to work early on in the fermentation & none-the-less an even lower pH that will be more inhibiting to potential pathogenic bacteria ....However, more amino acids will be "formed" by bacterial hydrolysis of the insect at 10 % salt than at 17.5 % salt & the level of aminos will rise the longer the time fermentation goes on. Under 4 months immersed in an inoculated/old rice bran medium (6 months if fresh medium) is probably ideal.... By being too long immersed & subjected to bacterial proteo-lysis this can lead to the formation of high levels of molecules called amines; which are formed from the breakdown of peptides & amino acids. Some amines are fine & yet for humans ingesting lots of histamine can provoke headaches (or worse) in many people. END


Thu Jul 03, 2014 10:52 pm
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