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Any ideas on fermenting insect larvae for consumption?
Wow! Looking forward to this discussion.
I would imagine that the processes traditionally used for fermenting shrimp in Asian cultures could apply to insects - will have to do some digging for any mention of traditional practices.
Fermented fish & fermented soy beans both are made with foods having protein & fat in them. So I think insect larvae would ferment somewhat similarly....
One of the major differences between working with fish & working with insects is that insects would be hard to individually remove their gut. To overcome this a solution may be to only ferment larvae that have gone through all their instars & are next going to be pupating....
Some pre-pupation insects, although I can not be sure of all, will empty their own gut contents before pupate in preparation for their non-active transition. These are not actively dedicating resources to metabolizing nutrients, rather reallocating energy for their metamorphosis into an adult insect. This purging, coupled with the way insect internal organs differ from fish organs is likely to make cleanly raised larvae fermentable....
Another difference is the insect exoskeleton poses more of a barrier than a fish skin does to the salt necessary to safely ferment using naturally occurring micro-organisms.
When salting fish the salt must get through the skin if one wants to reduce the bacteria & also knock down the level of any histamine in the fish tissues. Insect chitin would slow this process relative to fish & my estimate is over 5 days would be required to infiltrate in around the larval exoskeleton.
However for non-refrigerated storage of fermented larvae a 5 day salting is unlikely enough time. Most indigenous fermented fish gets 7 days to start fermenting & then is transfered into a medium for curing anywhere from 3 to 6 months....
Fermenting fish is done in many cultures & although use different containers as well as different timing most use what might be called an initial "dry" salting. Then after this 1st dry salt step they move on to culturing the salted fish without oxygen exposure (anaerobic) so there is no pathogenic microbes in the edible end product. At time of preparation for eating the fermented product the salt is either rinsed off or product soaked in water to float off some of the salt before consuming....
How much weight of salt used per weight of fish, & by extrapolation larvae, affects several factors. If you want highest fat in end product go with 5% salt; however this level of salt permits lots of micro-organism degradation of protein which releases odor volatiles depending on the rearing conditions, age & sex of fermenting item. As level of salt used goes up it kicks out fat from any muscle & by the time 15% salt is used the end product has what may be it's highest protein content; more salt doesn't mean more recovered protein....
Following is an example of a Malaysian Pekasam fermented fish recipe, as opposed to just the basic product described above. I think this could be adapted to larvae with a longer preliminary "dry" salting period than for fish. And the subject of how much salt to use was not parsed by the recipe's author, which is why was gone into above....
Pekasam uses mashed tamarind "paste" & brown sugar for savory flavoring which mellows the sensory aspects of a ferment, it "breads" item with ground roasted rice & then when served all is deep fried. There is a tightly covered period of weeks for anaerobic fermentation of the blend & that time span should be considered the minimum for a larvae substitution as well. Before there were plastic tubs with lids these types of second phase fermentation were done in fired earthen containers at ambient temperatures - in case things like clay is still appropriate technology for anyone....
The short Malay video in English is titled:
"Affnan's Aquaponics-How to Make Pekasam". Video link hopefully works (if not search by that title) =
fermentation is a way to preserve slaughter waste, as well. It typically involves lactic acid fermentation, so instead of salt, you can use whey or another source of lactii bacteria.
I am thinking it makes sense to partially crush or cracking the insects to allow salt/acid into the exoskeleton (if such exists, probably unnecessary with caterpillar/grub larvae), and an initial boil (in a salt solution?) would take care of any residual internal bacteria before moving on to the fermentation step
If you think insect larvae can be lactic acid fermented then maybe Kefir, which drops pH to level inhibiting pathogenic bacteria when the culture's lactobacillus breed up, would be a suitable agent....At first I thought of a solution of sanitized larvae immersed with milk Kefir "grains" since milk Kefir deals well with milk protein & fat; the lack of lactose "sugar" which lactic acid bacteria feed on would probably need to be compensated for by adding sugar....Another culturing agent could be the distinct microbial symbiotic of water Kefir "grains"; where put a layer of water Kefir grains down, add layer of sanitized larvae, cover with more water Kefir grains, add uppermost layer of sanitized larvae & close it up to the air for anaerobic fermentation period of probably a minimum of 1 week to 3 months. The end product would be more of a mush by layering than suspended in solution. However, the layered larvae ferment conceivably would be easier to reduce it's water content & thus suitable for pressing into patties for frying.
whey has sugar and lactic bacteria, so it's probably the simplest thing to use. Of course, any active dairy product, like live yoghurt or kefir would be teeming with bacteria. Lactic bacteria are everywhere, and very easy to cultivate. Just adjust the salinity, ph, or both.
I agree that it's best to grind up the insects prior to fermentation, but it may not be beneficial or necessary to boil them, because the change in ph or addition of salt is an effective method for pasteurization.
Insect larvae seem, to me, as the most versatile insects for fermentation. There are various methods in more detail I'd like to address in time. Different methods may be suitable for one climate without any energy input to work & another method better to employ in another temperature. As for the time in fermentation, any second stage fermentation & end product presentation these factors need to be determined by people experimenting with the variables.... Concerns about toxicity need not be overblown & listeria is controllable with sensible handling; many fermentations end with a pH so low that pathogenic bacteria can not thrive. The modern risk is mostly from contamination with staphylococcus aureus bacteria that can over-breed in a pre-fermentation medium (or post fermentation contamination during handling); which leads the S. aureus to secrete a self toxin to reduce it's own colony size. This toxin molecule, rather than S. aureus bacteria that is/has been fermented, is what can be toxic to animals/humans; furthermore, that potentially toxic molecule is not degraded during all fermentation methods, nor is that toxic molecule destroyed by simple pasteurization if use heat on medium before fermentation.... My interest is to get an aesthetic product which can be accepted by people & has a hedonic (pleasurable) appeal which insect food presentation lacks for many. I know poor in developing countries who like their indigenous "plate" & do not appreciate food just because it is touted as cheap or given as charity. Fermenting larvae offers shelf life & options to shape the product for preparing using common traditional cooking methods....
@gringojay - very excited to see where this thread goes, and what methods you can share as time permits! I think you are on point with the idea of fermented insects being a better baseline product for mass acceptable food stuffs than those simply processed in the current standard of drying and grinding.
Developing countries outside the temperate zone without reliable electricity might have problems keeping temperature down for using kefir & even possibly whey as a fermentation immersion agent. Kefir cultures start to get problematic in high temperatures; although I intend to revisit kefir's potential.... An alternative fermentation for those dealing with warm 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. Beer 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 "pickle".... 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, say, something like one full grow bag's worth of mealworm larvae.
Edit: I also added dissolved unpasteurized miso when first started up the rice bran medium at the same time added beer/water. Without miso it is definitely still possible to develop the fermentation bed. And other ferment leftovers (ex: alcohol lees) have been used for speeding up the inoculation that reportedly give good results.
Insect rice bran fermentation; Part II:
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/bbb/76/11/76_120414/_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/article/pii/S0168160510005696/ .... 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 ingesting lots of histamine can provoke headaches (or worse) in many people. END
This may be the simplest way to conserve mealworms & is an adaptation derived from research described elsewhere in the Forum (more details=12 Aug.'14 comment in thread Insect Food Cart Success). Research for orientation is repeated here is as follows:
(2012) "Microbiological Aspects of Processing and Storage of Edible Insects" makes several points about mealworms (& house cricket Acheta domesticus). Quote (from abstract): "... A short heating step was sufficient to eliminate Enterobacteriaceae, however some spore forming bacteria will survive in cooked insects.... Lactic fermentation of composite flour/water mixtures containing 10, or 20% powdered roasted mealworm larvae resulted... in...shelf-life & ... control of Enterobacteria and bacterial spores..." (ie: spores could not germinate & therefore naturally occuring spore forming bacteria did not grow on their host fermented mealworm larvae). When they are first boiled the mealworm larvae (& crickets) kept fine at the specified 5-7*C refrigeration temperature for more than 14 days. In contrast, if they only refrigerated & had not pre-boiled the fresh larvae then those became spoiled for human consumption by the original bacterial load within about 14 days.= http://www.sciencedirect.com/science/article/pii/S095671351200087
I took a wheat bran fed mealworm grow bag, harvested the pupae & separated out the larvae; I began with a roughly cleaned 657 grams of larvae. Those larvae (actually refrigerated overnight due to time constraint) were dumped into a large volume of fresh tap water & hand "washed"; the whole solution was then passed through a colander which did not allow the larvae to pass through. The wash water was discarded, the larvae were again submerged in fresh water, handled & the lot passed through the colander. I did this rinsing of the larvae a 3rd time & then let the mealworms settle to the bottom; those larvae that floated & the residual bran floating got scooped away with a small sieve (a tea leaf portion sieve), which needed a few passes to achieve. Black larvae were picked out & discarded.
Fairly clean at that point the settled larvae got poured into the colander & wash water discarded. A prepared large pot of boiling tap water then received the washed mealworms stirred into it & the few white pupae that roiled up were taken out of the cooking larvae. A few stirring passes were done & after 5 minutes a few foam clusters were skimmed off the water top for discarding.
After boiling for a full 5 minutes the heat was turned off & as soon as convenient the cooked mealworms were laddled & poured out over a cotton cloth lined colander to get rid of the spent water. The original 657 gram harvest was reduced somewhat when discarded the sieved floaters before boiling, but those cooked mealworms in their moist cotton filter bag weighed 863 grams. Later in the process I was able to determine the cooked mealworms without the filter bag weighed 764 grams; so there is some water absorbed after cooking them (estimated water retention is at least an extra 15% weight over original rough cleaned larval weight).
To preserve the cooked mealworms I took water kefir (not milk kefir) that had been fermented for 48 hours; a fairly low tech ambient temperature ferment (possibly not suitable for extremely high temperature zones unless done where ambient norm ameliorated by some tactic) which employs re-usable culture "grains". The cooked larvae were spilled out of their filter cloth into a bowl & submerged in a bit of the water kefir (not the culturing granules) to loosen any cooking water residue/bran; the larvae were then passed through a colander, "dirty" water kefir discarded & then the larvae again got a final water kefir bath before collection in a colander (2nd water kefir also discarded).
Finally the clean cooked (5 min.) mealworm larvae were put up in glass jars that I had with good lids on hand; I had some jars with 12 ounce (355 ml) graduated volume markings on their side so used those. The end product filled 3 jars to ~12 ounce level (weight of mealworm in each jar was ~255 gram/12 ounce volume) & then fresh (previously unused) water kefir was poured into those jars.
It took ~8 ounces (236 ml) of water kefir to cover each of those jars cooked mealworm larvae. A rough guide would seem to be a minimum of 1 ml water kefir to cover each gram of mealworms. So if you've a grow bag harvest of 1 Kg mealworms a Liter of water kefir should be enough to preserve them ( if one lacks enough water kefir my post-boiling double rinsing of the cooked mealworms is probably optional - or one could use just plain water in that step); to make 1 liter of water kefir you'd need only 1 cup of sugar to feed the re-usable water kefir grains.
My filled jars with cooked mealworms & water kefir ferment topping are in the refrigerator (door closed the temperature is 7* Celsius/45*Farenheit). I tested the batch of water kefir itself (not the mealworm jars' immersion water kefir in order to avoid cross contamination) & the water kefir is at 4.0pH .
That low pH is preservative & microbial growth other than lactic acid bacteria will not occur, nor sporolation. Furthermore, I think(?) the water kefir could be replaced periodically & if kept refrigerated the cooked mealworms would keep much longer that 2 weeks. They would be taken out in quantity needed & the low pH water kefir rinsed off in fresh water prior to preparing the mealworm for ultimate consumption.
Excited to hear how your worms hold up in these conditions, and how they taste!
Hi Andrew, - After just a few days with what I'll call here "Pickled Mealworms" (boiled 5 min. & preserved in water kefir) my impression is this may be the easiest ready-to-use & ready-to-eat product. I haven't worked out % protein/fat yet.
First crude, right out of the jar without rinsing off the water kefir they handle very well & spoon out easily. The taste has a hint of sweetness; which I think may be to the lactic acid bacteria feeding somehow on some component(s) of the chitin exo-skeleton. Chewed there is certainly chitin that flakes in between the teeth & although a sensory aspect there is no problem swallowing that.
Next I rinsed the pickled mealworms in tap water & patted them dry; there were only a couple of flakes trapped by the paper towel & I think likely from the exo-skeleton. Once rinsed & blotted dry about 9 pickled mealworms weighed 1 gram. If one made them with younger than imminently pupating larvae (as mine were) then this number/weight would change (as would % protein/fat).
From this point on I used only rinsed & blotted dry pickled larvae in preparing foods. The initial tactic was to drop about 80 grams in with a new to me brand of canned vegetable soup heated for about 3 minutes in a microwave oven; meal tasted fine, chitin went down fine. Unfortunately for me I did not feel well that day & can not say what role that meal played in things.
I did put 50 grams pickled mealworm on top of store bought hummus with lettuce on whole wheat bread. Tasted mostly of hummus, chitinous flakes went down OK & I did not experience anything untoward for the hours after the sandwich; I deliberately ate nothing to avoid confusing results & only partook of water.
Another store bought soup (tomato w/roasted pepper) meal was heated 1st alone in the microwave & then once hot I stirred in pickled mealworms. I then gave that 1/2 minute on high in microwave & ate the meal. Tasted fine, chitinous flakes had no impact on taste & again I refrained from any further food/beverage for hours to judge any after effects; there were none.
After dealing with chitin in the mouth I decided to try another tactic with the rinsed & blotted dry pickled mealworms. I took what turned out to be 29 grams (after paper towel blotting) & put that in 120 ml water (spring water, not chlorinated tap water). This was blended at high speed in a small blender like what is called a "Bullet" blender.
I then filtered the solution through a cloth with a weave similar to T-shirt fabric. The liquid comes out beige & reminded me of almond "milk"; the chitin/pulp left in the cloth
weighed 5 grams (from an initial 29 grams).
This pickled mealworm liquid extract I then added into an already heated-up (microwaved) soup. I just stirred it right in to even out the 2 temperatures & ate that preparation hot. The taste was really the soup's & there was no chitin distraction in the mouth to work around. The next day I made some of my own slow cooked ("crock pot") lentil/pepper/eggplant/curry/cocconut milk soup & added the same pickled mealworm
"milk" after the soup had cooked; it lightened the color a little but meal tasted great.
Once I settled on the blending/filtering sensory aspect & that there's no need to cook again the already cooked pickled mealworms I tried beverages. I took carrot juice & stirred into it the pickled mealworms' water extract. It dilutes the carrot juice & lessens the sweetness of course; but without the mouthful of chitin it's a nice drink.
I made a point of not eating anything with the juice concoction & was very impressed with how well it allayed hunger for a long time. I think it is a combination of the fat content & protein which moderate any tendency of carrot juice sugars to play with one's insulin. I did not test blood sugar beforehand or in intervals over the next 2 hours to better assess that detail. This combination of carrot juice & pickled mealworm extract was made twice so far with the same result of good energy level, no hunger.
This afternoon I tried the pickled mealworm extract with frozen red grape juice concentrate; a ratio of about 1part concentrate to 2 parts watery extract. The pickeled mealworms weighed 36 grams (blotted) & before blending had a volume of 60 ml (4 Tablespoons). The total drink was ~400 ml (~14 oz.) with ~1/3 of that being grape juice concentrate; anyway at that strength grape overcame any other flavor. Again it seemed to allay hunger & the protein/fat content is probably why (probably slows insulin spike).
When I say allay hunger I mean that made these beverages as in between meal time drinks in order to avoid confusing any effects with solid foods. Thus when my usual meal time next came along I was not hungry when normally would be. And after drinking the concoction(s) I had a good energy level for my daily routine activities.
P.S. ...ratio carrot juice was 240 ml to 120 ml pickled mealworm fluid extract (~30 gr. larvae, blotted wt.), -> beverage volume = 360 ml. (total drink).
Week has passed since made the "pickled" mealworms & I uncapped the 2nd of 3 jars since jar #1 all used up. Unlike jar #1 the 2nd jar immediately overflowed & this means that the water kefir has been fermenting carbohydrates on the 5 minute boiled larvae.
The unrinsed taste of the 2nd jar "pickled" mealworms seemed to have a sweet nuance just like jar #1 ones did; in fact even sweeter, but that's probably a trick of memory.
The fact that lactic acid fermentation is going on even under a standard refrigeration temperature is not a problem. The water kefir from jar #1 still measured 4.0 pH & at
that pH noxious bacteria are not growing, the fermentation agents are not a risk.
I used some of the "pickled" mealworms from jar #2, rinsed them in cold water, drained them & there were a few exo-skeleton shed flakes (chitin). The cleaned larvae got blended in water & unlike before simply strained through a fine mesh kitchen type of collander.
Although having dispensed with cloth filtering I did not see any chitin come through in the extracted solution; this makes end processing simpler. When I mixed in carrot juice I didn't pay any attention to proportions this time; tasted fine.
In light of the ongoing fermentation I took what was left of jar #2 (most), strained the larvae out without washing them in water & discarded the original water kefir. Then I put the larvae in a new jar & covered them with new (unused before) water kefir. This time the lid has a fermentation air lock (cheap item sold for home brewing) & if fermentation goes on inside the refrigerator the air lock will control any pressure building up.
Jar #3 got transfered to a similar new jar, closed with a lid that has an air lock & put back in the refrigerator. This is to compare the 2 remaining portions of "pickled" mealworms made at the same time & see if changing out the water kefir makes any difference in storage.
What the 1st week of post-production storage reveals is that it would be more practical to age the water kefir pickled boiled larvae from the beginning in containers with an air lock, even if immediately refrigerated. Any container that can be tightly closed should be adaptable to an air lock; just make a correct size hole, fix a gasket (sold with airlocks) in that hole, push in the airlock, fill the airlock to small water level (CO2 diffuses into the water but contaminants can't pass inside) & snap on the airlock's lid.
@gringojay - this is very exciting, in particular your experience re:hunger after consuming the mealworm supplemented drinks. Hints at many possible applications, thinking Soylent type stuff... (http://www.soylent.me/)
14 day old refrigerated "pickled" mealworms still perfectly edible. A few hours ago before noon made a grape juice blended drink (filtered out exo-skeleton/chitin) & again powered through the early mid-day without hunger.
I have to calibrate a blood glucose meter & then try to see if there's any meaningful
glycemic data. My guess is the larval fat body content is a big factor in counteracting the normal sugar rush & then crash from juices like grape/carrot affect on insulin.
I've another cull of larvae all pickled up & this time did not pack the jar so full. With that head space in the jar the brew doesn't seem to be bubbly. That extra volume of water kefir to boiled larvae ratio looks more practical & then apparently there's no need for an air lock set up after all (just crack the seal, burp any CO2 & re-close jar).
Although not all sorted out on how to detail it I do think there is a good chance this type of a fermentation could be adapted to a product(s) that did not need immediate refrigeration for a reasonal ambient temperature shelf life. I'm not trying to copyright a product & others might improve on the approach(s).
There are 2 prospects for ambient temperature packaging of pre-boiled fresh mealworm larvae being fermented in liquid that I will try to write up sometime soon. I even think 1 blended version might be practical that even has those flakes of larval exo-skeleton removed (I don't miss that filtered out).
As for "soylent": I think it sounds as if it is making all the "right" claims. Unfortunately I think it is based on some relatively recently discredited axiomatic beliefs about diet. Of course it can be a convenience food & seems to be a very practical one at that.
I would suggest to anyone interested in validating their claims to 1st have a fasting (morning) NMR lipo-protein test before start using it as a meal replacement in order to establish what are the particle size of LDL cholesterol & how numerous those particles are. That same NMR (nuclear magnetic resonance) will also reveal triglycerides & HDL.
There are on-line providers of pre-paid authorization in most USA states (finicky California included) & you pay out of your own pocket; a local blood-draw lab phlebologist takes your blood, sends it out to lab doing the test & results come to your email/postal address. After a period of time (give it at least 3 months, could go longer if need to establish a routine) the re-test the NMR cholesterol etc. to compare results.
If your particle size is "small" & it was originally "large" then "soylent" is unfortunately just hype for your cardio-vascular system - even if your LDL goes "down" (sorry to say). Conversely, if you started out with "small" LDL particle size & on "soylent" they changed to "large" bouyant LDL particles then the product is living up to it's claim of being a cardio-vascular benefit (for you at least).
If 'soylent" causes no change in LDL particle size then it is irrelevant for that component of cardio-vascular health. As for triglycerides: if "soylent" drops your triglycerides levels it's good. On the other hand if it drops your HDL (which I suspect it might in some, like those without genetic high HDL) it's not so good.
It would be of great evaluative worth to also test fasting insulin & have the laboratory test for blood sugar; I prefer testing what is called "serum glucose". If any of those change favorably (good usually means downward readings, unless your morning level is always hypo-glycemic) then "soylent" is doing well by you. The same online testing facilitators will arrange for these 2 lab tests as well; you pay (unless have very co-operative insurance company & are already a diagnosed diabetic) .
If you've only got your recent insurance paid HbA1c test results you can estimate your pre-soylent average blood sugar. Multiply your HbA1c number by 28.7 and subtract 46.7 from that number (ex: if HbA1c is 5.4% then average blood "sugar" at that lab reading was108.28). Then next insurance paid HbA1c test after being on a "soylent" themed diet compare that average blood sugar to your own 1st data; if it's lower then you are getting some benefit in that realm.
Anyone with access to a calibrated home glucose meters you can test & compare your "fasting" morning blood sugar; fasting test blood can be a drop from somewhere other than your finger. If, on average, that goes "up" then "soylent" is not doing you individually any favors in that parameter. I think it is unlikely that used as directed it would repeatedly raise fasting blood sugar in most adults, but without individual data & parsing other food ingredients one is only theorizing.
The most personalized assesment for any "soylent" affect on blood sugar is to use a calibrated home glucose meter & test a drop of finger blood before eating/drinking anything with "soylent". Then ~15 minutes after finish meal re-test a new finger blood drop's glucose & as digest meal repeat; re-testing finger blood drops periodically for up to 2 hours to see what affect "soylent" has on your own blood sugar dynamic.
Basically, if your blood sugar stays elevated for a protracted period after
consuming "soylent" then it's not controlling hyper-glycaemia. Although, to be fair, when finessing "soylent" into your diet you may not be using it as directed & it can't be blamed as the food ingredient responsible for the hyper-glycemia (high blood "sugar").
Finishing up here; the reason I detailed those blood tests is not to disparage "soylent" claims, it was because they are the same type of baseline data needed for insect consumption. Namely, is eating any particular insect actually demonstrably beneficial for cardio-vascular concerns &/or relevant to improving blood sugar for anyone. Any Tiny-Farm fans with access to a home glucose meter should try to get some data from willing associates. Those intending to use insects as a significant dietary (protein?) replacement should not waste their time without budgeting in a before & after NMR lipo-protein - if they want to be able to prove any cardio-vascular benefit; likewise for fasting insulin, if want to prove any rationale for some weight control.
Back in June Andrew mentioned fermenting shrimp techniques might be adapted. Here is an insect adaptation of a Philipine shrimp fermentation that softens the chitin exo-skeleton.
First salt every 5 grams of cleaned larvae (ex: mealworms) & if use a flying insect like crickets remove the wings & heads. Mix insect together with 1 gram of salt & give this time to react.
Now, the Philipine shrimp are not cooked prior to salting & part of the fermentation is a dynamic involving the shrimps' gut microbes. For those raising the insect they'll ferment I am inclined to believe these do not need to be pre-cooked. If using random sourced insects then of course one doesn't know where an insect had been & a pre-boiling might be worth trying (bear in mind it may affect the end-product).
2nd step is to add cooked rice that no longer feels hot on your skin, but is not yet cool to your cheeck. Mix together at least 2 parts of cooked rice with each 1 part of the brined insect; include the salt in with everything too.
3rd step is to thorougly compact (don't leave spaces of air) the mixture of salt, insect & rice into a narrow neck container where it can ferment for anywhere from 3 - 10 days; depending on your temperature while mix is fermenting. Make sure to leave a bit of expansion room, put a little layer of the cooked rice on top of everything & close off air from getting at the fermenting product (a jar with lid works & a ceramic container would need a press weight to stop product floating into air).
4th step is to unpack the fermenting mass & cook it up to stop the ripe smelling fermentation. Referigerated it's taste/smell should be stable for at least a month.
Uncooked/unrefrigerated it will keep getting "funky" but aside from any upper surface layers of mold is likely to still be safe to consume (crude it needs to be stored out of light/heat).
It is not a main dish, but more a seasoning to blend into a meal. Once cooked in with
something & subsequently refrigerated that dish's left-overs can be re-heated or incorporated into some other dish. By blending the ferment in with food that had not been fermented in with it the ferment's odor molecules will over-power the dish; figure after a week in the fridge when re-heat that dish it's sensory quality will have diminished.
I did some experimenting, doing some improvised sauce, mixes, though mostly with raw shrimps...
There are things to think about: salt, or chili, spices, pepper, garlic etc all have a positive effect allowing good bacteria and killing some harmfull ones if present. Also, if fermenting for longer periods of time, think about the risk of botulism which could be quite dangerous, so better to air the jar once in a while, as botulism only happens when there is no contact with air for long periods of time.
And if you look at kimchi, some ancient recipes have some raw seafood in it... My experience is that non vegetal ingredients will definitively accelerate the fermentation process... But you'll need to have some prior experience with fermentation if you want to start to work with non vegetal ingredients, it'll give you a good base and feel to judge if something has the right microorganisms in it...
A good visual presentation of how northern Malaysia ferments fish to preserve the harvest without refrigeration. This is a method which I have previously suggested can be adapted to fresh insect larvae. In developing countries this may be a good tactic to consider for post-harvest distribution.
The steps are to first wash, salt, coat with a savory brown sugar/molasses/tamarind dip, layer some of the product out, then inter-layer with pan burnt white rice, cover against dust/bugs & set to cure someplace out of sun's heat. A narrow fermentation vessel that is taller than it is wider is easier to keep control of mold growth on top layer than a square kind of container.
After 1 week rework array so top layer & bottom layers reversed; ready to use after 2 weeks. First video's ending has old time trick of using bowl of iron nails atop mass to react with oxygen in way that controls unwanted microbial contamination spreading.
Affnan's presentation in 3 parts links are as follows; his earlier demonstration was cited above in this same thread (June 2014). In order of the steps' demonstration =