Effects Migration Of Aroma Components From Tan Lamb In The Process Of Freeze-drying

Tan Lamb is a prepotent sire in Ning-xia, it has some characteristics, for example the meat is delicate and delicious, the fat distributes uniformity, the nutrition is abundant and the aroma is unique. So it has a better market potential and development prospect. But the shelf life of traditional tan lamb products are not long and they are not convenient for long distance transportation, because of which limit the export. Preliminary study on migration mechanism of aroma components from tan lamb in vacuum freeze drying laid a foundation in this article, and methods and results were as follows:.(1) The volatile compounds from Ningxia tan lamb was extracted by headspace solid-phase microextraction (HS-SPME) meanwhile the condition of HS-SPME was optimized. The volatile compounds were analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). The best conditions were75μm CAR/PDMS extraction fiber,60℃extraction temperature and30min extraction time. The characteristic aroma compounds from Ning-xia tan lamb were:hexanal which had a weak fruit flavors and rancidity, heptanal which had a fatty sour, ethyl caproate which had a fruit aroma, nonanal which had a strong fatty flavors, nonanol which had an orange fragrance and grease taste and myristic acid which had a dense creamy aroma.(2) Adsorption capacity and influencing factors of SSMP to different characteristic aroma compounds were studied by DHS and GC-MS. The experimental results showed that the adsorption capacity of SSMP to different characteristic aroma compounds was different, and the concentration, pH and ionic strength of SSMP all affected the adsorption capacity of SSMP.(3) The microstructure of longissimus dorsi and SSMP gel was observed and analyzed by scanning electron microscope (SEM), and physical characteristics of porous medium from tan lamb meat was studied. The experimental results showed that microstructure of longissimus dorsi was tidy, apparent and arranged in order. The bigger voids and slits were filled in SSMP gel, and voids were interconnected in each direction. In addition, the microstructure was bound up with water retention of gel, the microstructure was compact and homogeneous when water retention was high, on the contrary, the microstructure was coarse, loose and asymmetric.(4) SSMP of tan lamb meat was vacuum freeze drying and adsorption conditions of SSMP to characteristic aroma compounds were tested after vacuum freeze drying. The influence on adsorption capacity of SSMP to characteristic aroma compounds in the conditions of vacuum freeze drying was studied. The experimental results showed that with the pressure increased, adsorption capacity of SSMP to characteristic aroma compounds was enhanced, and adsorption capacity of SSMP to characteristic aroma compounds was maximal when pressure was more than40Pa. With the temperature increased, adsorption capacity of SSMP to characteristic aroma compounds was weaken, and adsorption capacity of SSMP to characteristic aroma compounds was maximal when the temperature was50℃.