Chemistry ntawm lub skewer: yog cov kws tshawb fawb zoo ntawm kev ua noj barbecue

2024 Tus sau: Malcolm Clapton | [email protected]. Kawg hloov kho: 2023-12-17 03:58

Dab tsi tshuaj hloov pauv tshwm sim nrog kebab ntawm txhua theem ntawm nws qhov kev npaj.

Kev npaj Kebab, los ntawm tus kws tshuaj ntsuam xyuas qhov pom, yog txheej txheem nyuaj, ntawm txhua theem uas muaj ntau qhov kev hloov maj mam thiab cuam tshuam cuam tshuam. Yog hais tias koj mus cuag qhov teeb meem ntse, daim ntawv qhia rau ib tug zoo kebab yuav muab piv rau ib tug neeg txoj kev ntawm cov organic synthesis - los yog txawm tshaj lawv. Thiab, raws li nyob rau hauv ib tug tag nrho-fledged scientific xyaum ua tej yam, nyob rau hauv kev npaj ntawm barbecue muaj ntau cov ntsiab lus uas qhov optimization ntawm tus txheej txheem nyob ntawm seb - thiab yog li ntawd lub saj thiab aroma ntawm cov khoom kawg.

Yog li, txhawm rau ua noj kebab, koj yuav tsum tau ua ob kauj ruam tseem ceeb: marinate cov nqaij thiab kib nws hla hluav taws. Tab sis ua ntej, cia peb xam seb cov nqaij yog dab tsi - nyob rau hauv cov nqe lus ntawm chemistry.

Nqaij

Dab tsi peb hu ua nqaij thiab yuav hauv khw muag khoom uas yog nqaij npuas thiab nqaij nyug yog qhov tseeb ntawm cov tsiaj skeletal striated musculature. Tshwj tsis yog, ntawm chav kawm, peb yuav tsis xav txog offal, xws li lub siab, uas tsis siv rau barbecue. Ntxiv nrog rau cov leeg nqaij nws tus kheej, adipose thiab cov ntaub so ntswg sib txuas, uas nyob ib sab ntawm lawv, kuj raug xa mus rau cov nqaij.

Cov nqaij mos muaj cov qauv xav paub. Peb tau accustomed mus rau lub fact tias lub hlwb ntawm peb lub cev feem ntau yog heev me me, tsis pom ntawm lub qhov muag. Cov txheej txheem ntawm cov leeg yog cov leeg nqaij - thiab qhov no yog ib lub xovtooj loj ob peb centimeters ntev thiab ntau pua micrometers inch. Nws yog tsim los ntawm fusion ntawm ntau txhiab ntawm lwm lub hlwb, vim muaj peev xwm muaj ntau txhiab nuclei hauv cov leeg nqaij.

Cov cuab yeej tseem ceeb ntawm cov leeg nqaij fibers yog lub peev xwm los cog lus. Nov yog qhov peb (thiab lwm yam tsiaj) txav peb ceg ceg - thiab ntau dua. Qhov no yog muab los ntawm cov protein tshwj xeeb - actin thiab myosin. Lawv yog cov elongated molecules uas tsim cov pob ntev hauv cov hlwb. Raws li kev cuam tshuam ntawm lwm yam teeb meem (paj hlwb impulse), cov pob khoom no pib txav mus rau ib leeg, rub mus rau qhov chaw. Tag nrho cov fiber ntau muab faib ua cov sib txuas sib cais - sarcomeres, fastened ua ke.

Tsis tas li ntawd, cov nqaij muaj cov protein ntau elastin thiab collagen nyob rau hauv cov ntaub so ntswg. Lawv yog cov feem ntau lub luag hauj lwm rau cov neeg kho tshuab yam ntxwv ntawm cov nqaij (toughness, thiab lwm yam). Protein myoglobin yog lub luag haujlwm rau cov xim ntawm cov nqaij. Feem ntau, nqaij yog cov khoom lag luam muaj protein ntau, tab sis, ntawm chav kawm, muaj cov rog txaus hauv nws.

Pickling

Cov nqaij yog marinated thiaj li yuav daws tau ntau yam teeb meem ib zaug: ua kom nws softer, muab nws ib tug ntxiv tsw thiab nqa tawm thawj antimicrobial kev kho mob.

Collagen molecules, uas txiav txim siab hardness ntawm nqaij, feem ntau tsim muaj zog fibers, fibrils. Lub rooj sib txoos no tshwm sim nyob rau hauv kev cuam tshuam ntawm hydrogen bonds - qhov attraction ntawm ib nrab nqi (polarized) amino acid fragments. Raws nraim tib qho kev sib txuas tshwm sim ntawm cov dej molecules - nruab nrab ntawm hydrogen atom ntawm ib lub molecule thiab cov pa oxygen ntawm lwm tus.

Ntau cov marinades yog acidic vim muaj cov kua qaub hauv lawv - feem ntau acetic (piv txwv li, hauv cawv, mayonnaise lossis vinegar), txiv qaub thiab lactic acid. Soy sauce thiab teriyaki sauce kuj muaj cov kua qaub nruab nrab - lawv muaj ntau cov pyroglutamic acid, nrog rau succinic, citric, formic thiab acetic acid.

Qhov no txhais tau hais tias muaj ntau cov hydrogen cations hauv marinades uas muaj peev xwm khi rau cov protein molecules thiab protonate lawv. Qhov no hloov pauv qhov kev faib tawm ntawm cov nqi hauv cov molecules thiab cuam tshuam cov qauv zoo ntawm hydrogen bonds, uas ua rau muaj kev hloov pauv hauv geometry ntawm cov protein molecules. Yog li ntawd, cov proteins yog denatured: collagen thiab actin fibers o, soften, collagen maj dissolves.

Cov nyhuv tib yam tuaj yeem ua tiav yam tsis tas siv cov kua qaub. Piv txwv li, qee cov txiv hmab txiv ntoo sov, xws li papaya thiab pineapple, muaj cov enzymes uas zom elastin thiab collagen rau hauv ib qho amino acids, thiab cov kab mob thiab fungal proteases tuaj yeem ua rau cov leeg nqaij fiber ntau. Muaj cov txheej txheem ntawm lub cev ntawm softening nqaij - tuav ntawm lub siab ntawm qhov kev txiav txim ntawm ob peb txhiab cua, uas kuj ua rau denaturation ntawm cov proteins.

Qhov ceev ntawm cov nqaij yog marinated kuj nyob ntawm seb muaj pes tsawg leeg ntawm marinade. Piv txwv li, muaj cawv nyob rau hauv lub marinade tau qhia kom ceev cov txheej txheem marinating. Qhov no yog vim qhov tseeb tias cov lipid membrane ntawm cov hlwb dissolves zoo dua hauv cawv dua hauv dej. Ntau yam khoom pabcuam, xws li tannins hauv cawv thiab npias, kuj ua lub luag haujlwm hauv kev sib tw nqaij.

Nws yog tsim nyog sau cia tias pickling tsis tas yuav ua rau nqaij softening. Hauv qee qhov xwm txheej, marinating ntau dhau (hauv qhov muaj kua qaub lossis cawv ntau dhau) poob dej thiab ua nyuaj dhau. Cov nyhuv tib yam tuaj yeem ua tiav los ntawm overcooking nqaij - tom qab ntawd feem ntau ntawm cov dej yuav yooj yim "ya" ntawm nws.

Qhov thib ob tseem ceeb tshaj plaws cov nyhuv yog antimicrobial. Tab sis tsis tsuas yog acids yog lub luag hauj lwm rau nws, tab sis kuj lwm yam khoom ntawm marinade, xws li dos. Muaj ntau cov kev tshawb fawb tau mob siab rau ntau txoj hauv kev los rhuav tshem cov kab mob phem hauv cov nqaij; nyob rau hauv ib qho ntawm cov kws sau ntawv xav paub ntau tshaj plaws, lawv tau npaj yuav ntxiv kev ua hauv ib da dej ultrasonic rau cov qauv txheej txheem ntawm marinating nqaij hauv npias.

Nws yuav tsum raug sau tseg tias theem thib ob ntawm kev ua noj shashlik pib cov synthesis ntawm qee cov carcinogens - cov khoom tsis zoo uas tuaj yeem ua rau mob qog noj ntshav. Qhov no siv tshwj xeeb rau cov khoom ntawm charring ntawm roj dripping mus rau coals. Cov no suav nrog benzo [a] pyrene thiab lwm yam polyaromatic hydrocarbons.

Lwm chav kawm ntawm carcinogens tshwm sim los ntawm cov nqaij charring yog heterocyclic amines. Cov tshuaj no tuaj yeem tsim cov complexes nrog DNA thiab cuam tshuam rau cov haujlwm tseem ceeb ntawm cov hlwb. Ib txoj kev tshawb nrhiav txawm pom Dietary Benzo [a] Pyrene Intake thiab Risk ntawm Colorectal Adenoma los cuam tshuam kev noj cov nqaij nyug los yog grilled nrog qee yam qog nqaij hlav. Yog li, nws raug pom zoo kom txo qis kev siv cov tshuaj no kom ntau li ntau tau. Tab sis pickling tuaj yeem pab tau ntawm no thiab.

Muaj ntau qhov kev tshawb fawb los ntawm Portuguese thiab Spanish chemists uas qhia tias qee hom marinades txo qis qhov tshwm sim ntawm cov carcinogens tsim. Piv txwv li, marinating nyob rau hauv maub npias ib feem inhibits cov nyhuv ntawm npias marinades ntawm tsim ntawm polycyclic Aromatic Hydrocarbons nyob rau hauv Charcoal-Grilled nqaij npuas, tsim ntawm polyaromatic hydrocarbons, thiab txo qhov feem ntawm heterocyclic amines tsim, marinades raws li wine, npias, los yog txawm yog cov uas muaj tshuaj yej yuav tsum tau xaiv. Feem ntau, cov nyhuv ntawm marinades ntawm kev tsim ntawm polyaromatic hydrocarbons feem ntau tseem tsis tau nkag siab zoo. Lwm yam inhibitors muaj xws li dos, qej, txuj lom, thiab citric acid pickles.

Frying

Marinating, vim lub denaturation ntawm feem ntau ntawm cov proteins, ho speeds li txheej txheem ua noj. Qhov no tsis txhob raug tshav kub ntev thiab evaporation ntawm dej ntau dhau. Nrog rau kev nrawm ntawm cov protein denaturation, charcoal frying pib ntau lwm cov txheej txheem tshuaj hauv cov nqaij.

Thawj ntawm cov no yog qhov paub zoo txog Maillard cov tshuaj tiv thaiv. Nws yog nws lub luag haujlwm rau kev tsim cov tshuaj tsw qab muaj zog, uas muab cov ntxhiab tsw tshwj xeeb rau cov nqaij kib. Amino acids pom nyob rau hauv cov nqaij thiab cov suab thaj nkag mus rau cov tshuaj tiv thaiv no. Yog li ntawd, complex heterocyclic compounds yog tsim, derivatives ntawm furan, thiophene, alkylpyridines thiab pyrazines.

Qhov tshwj xeeb tsw profile rau txhua hom nqaij yog qhov sib txawv, nws yog txiav txim los ntawm qhov sib piv ntawm cov concentrations ntawm ntau txhiab ntawm cov tshuaj tsw qab tsim thaum lub sij hawm kib. Nyob rau hauv cov ntaub ntawv ntawm kib nqaij qaib thiab nqaij npuas, cov khoom condensation ntawm cysteine cov suab thaj, xws li 2-methyl-3-furanethiol thiab nws dimer, nrog rau 2-furylmethanethiol, ua lub luag haujlwm tseem ceeb hauv cov aroma.

Tau kawg, lwm cov amino acids kuj ua rau cov suab thaj. Methionine, piv txwv li, cuam tshuam nrog cov suab thaj thiab degrades rau methional, ib yam khoom uas tsw zoo li cov qos yaj ywm kib.

Nws yog tseeb hais tias cov proteins thiab suab thaj tsis tsuas pom nyob rau hauv cov nqaij. Yog li ntawd, cov tshuaj tiv thaiv Maillard plays lub luag haujlwm hauv aroma ntawm lwm cov tais diav ib yam nkaus. Piv txwv li, cov khoom ci (thiab qee hom mov) tsw zoo li 2-acetylpyrroline, cov tshuaj tiv thaiv ntawm proline thiab qab zib. Hauv qhov me me, cov khoom no kuj tshwm sim hauv cov nqaij kib.

Qhov thib ob chemical txheej txheem yog rog charring. Cov rog yog esters ntawm glycerol thiab organic fatty acids xws li stearic, palmitic, thiab lwm yam. Thaum tshav kub kho, lawv raug hloov mus rau aldehydes xws li hexadecanal, hexanal, thiab lwm yam. Interestingly, ci nqaij nyuj muaj aldehydes ntau tshaj li nqaij qaib thiab nqaij npuas, uas ua rau lawv saj txawv. Thiab tus yam ntxwv yaj tsw tsw yog vim 4-methyloctanoic thiab 4-methylnonanoic acids.

Cov txheej txheem thib peb yog cov tshuaj tiv thaiv ntawm cov khoom ntawm carbonization ntawm cov rog thiab cov khoom ntawm cov tshuaj tiv thaiv Maillard. Cov no yog txhua yam alkanethiols, alkylpyridines, alkyl derivatives ntawm thiophenes, pyrroles, thiopyrans, thiazoles, thiab hais txog. Cov alkyl nyob rau hauv lawv tshwm sim los ntawm fatty tivthaiv, thiab heterocyclic ib feem los ntawm Mayar tivthaiv.

Tsis tas li ntawd, lwm yam kev cuam tshuam nrog cov amino acids tshwm sim thaum ci nqaij. Yog li, cysteine thiab glutathione tsim trithiolans thiab dithiazines thaum kho cua sov, uas kuj ua rau muaj txiaj ntsig zoo rau tsw.

Lub saj thiab aroma ntawm kebabs yog muab tsis tau tsuas yog los ntawm cov khoom decomposition ntawm amino acids, qab zib thiab rog, tab sis kuj los ntawm cov khoom ntawm thee combustion. Ntawm lawv, nws yog ib qho tsim nyog hais txog syringol (nws lub npe, los ntawm txoj kev, los ntawm Latin lub npe rau lilac, Syringa vulgaris) thiab guaiacol - lawv tau tsim thaum lub sij hawm tawg ntawm lignin, ib tug binder rau cellulose molecules nyob rau hauv ntoo. Cov tshuaj no muab cov kebab (los yog barbecue) nws cov yam ntxwv tsw ntxhiab tsw.

Kaum ob ntawm cov ntsiab lus ntawm kev ua noj ua haus cuam tshuam rau qhov sib piv ntawm cov tshuaj tsw qab hauv qhov ua tiav kebab: kub, lub sijhawm ci, xaiv cov thee, nqaij, marinade, lub sijhawm marinating. Thiab qhov no yog lub sijhawm zoo rau, ua tub rog nrog txoj kev tshawb fawb, nrhiav koj tus kheej daim ntawv qhia zoo rau barbecue koj tus kheej thiab, tej zaum, txawm sau ib tsab ntawv tshawb fawb txog nws - nrog rau cov lus piav qhia tshwj xeeb ntawm qhov kev sim.