Los yog decompression ntim nqus, raws li tus cai hais txog qhov atmospheric siab, yog lub luag hauj lwm tseem ceeb uas lub hnab nqus pa, thiaj li yuav pab tiv thaiv cov zaub mov txhob lwj los yog deterioration. Nqus ntim yog hnab ntim cov khoom noj thiab cov pa mus tsis pub dhau rau ntawm tes uas siv deprived, kom muaj dab microbial poob "nyob chaw". Nqus plua plav tseem tsis pub mov, oxidation kom cov zaub mov tsis saj tsis tau, deterioration los txo qhov uas tsi vitamin A thiab C.
Ntim tshuab nqus tsev yog xis teb xis chaw nyob rau hauv lub tshuab nqus tsev, thiab ces kam nitrogen, carbon dioxide thiab lwm gases. Nitrogen yog ib inert gas, los ntawm qhov hais tias, kom lub hnab nqus kom muaj lub siab zoo los tiv thaiv lub hnab nyob nraum zoov cua mus rau hauv lub hnab ntim cov khoom noj ua si ib tug tiv. Pa roj carbon dioxide inhibit pwm, kab txhob lwj thiab lwm microbial kev ua haujlwm. Qee yam, xws li crispy los yog crunchy zaub mov, deformation thiab coj mus tus roj zaub mov, muaj cov ntse hau los yog hardness siab yuav hno lub hnab nqus lwm yam zaub mov, tom qab koj sau rau lub ntim nqus, hnab tshuab tshuab lub hnab nyob nraum zoov pressures ntau dua atmospheric siab, tau zoo txhob noj compression crushing, deformation, thiab tsis muaj feem xyuam rau cov tsos ntawm lub hnab thiab luam ntawv thiab decorating. Qib thiab kev loj hlob ntawm lub tsev loj me nqus tsev packed, cov uas yuav muaj ntau dua, ib txhia yuav maj mam hloov lub ntim txhav.