We've performed thermal coagulation of bulk (~4x4x4 cm) porcine muscle, LD (loin) tissues using two different heating protocols. In the first one, the sample was submerged into a jar with boiling water and heated for ~ 40 min, until the internal temperature reached 85-90 deg C. In the second one, the sample was inserted into a Ziploc bag and then into the jar with boiling water following the same heating time with the same end temperature. We've noticed that these two protocols triggered different changes in optical scattering of the samples. BTW, water loss was the same in both cases.
I'm wondering what kind of changes in the sample structure, morphology, biochemistry etc. do these protocols introduce such that they are manifested in optical scattering. Or, perhaps just tell me what is (or can be) different in these samples, and I'll try to relate it to optical properties by myself:) Also, any resources analyzing different methods for thermal processing of meat will be helpful.
Thanks in advance!
P.S. Details of optical measurements and the method for extracting optical absorption and scattering of tissues can be found here:
https://www.researchgate.net/publication/261718471_Optical_absorption_and_scattering_properties_of_bulk_porcine_muscle_phantoms_from_interstitial_radiance_measurements_in_650900_nm_range
Article Optical absorption and scattering properties of bulk porcine...
Thanks for sharing your question with me, but can only make a guess and add some of my brainstorming thoughts:
1) direct contact of raw meat with water may have some osmotic effects, which otherwise where prevented by the plastic bag. Even without boiling, muscle fibres and cells may have some changes in first osmotically attracting water (for example, like red blood cells explode within 30s of distilled water, at room temperature), but just diffusing water may also have some effects, rinsing mobile ions out of the tissue. This direct contact effect with water may be responsible for some changes on the surface, but perhaps in the deeper tissue of your sample - but at the end, after reaching the temperature of around 90 degrees, the
2) assuming that you used some vacuum pump to remove any isolating air bubbles, the plastic itself may have a different temperature transporting capacity (there might be a better expression..) I mean, the plastic can isolate, therefore leading to a different time curve of how fast the denaturation process goes through the meat... (what happes if you use 2, 2, 3, 4 ,5 plastic bags at once - any delay of temperature increase? The final temperature should be met, but at a slightly later time point (?).
3) I could be wrong and anything else is more relevant.
I think the answer is simpler: Submerged in water, there will be ionic exchange. Protected from water, this exchange does not occur; a concept used frequently to manipulate the outcome of commercially packed ready-to-cook meats. Cooking loss is not affected, but color most definitely. When the meat is sealed under vacuum (less oxygen), the outcome will also differ from sealed in oxygen containing air.
Thanks, Francois. Since ionic strength and PH are known to affect a form the myosin is in, it may have different manifestations in optical scattering indeed! Good point!
Hi Serge. Sorry but this specific question is out of may expertise field
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