Effects Of Raw Materials, Processing And Preservation On The Quality Of Concentrated Soup Of Yak Bone

The effects of raw materials and processing on the quality of concentrated soup of yak bone were mainly researched, and the preservation was also studied in this paper. The aim of this study is to improve the processing technology and offer a scientific and practical procedure for the concentrated bone soup.Firstly, effects of raw materials on the quality of concentrated soup of yak bone were studied. The soup quality of yak bone from different parts were determined by sensory evaluation and the soluble solid content, the results showed that the shank have more advantages in producing bone soup while the rib and chine had less contributions to the sensory quality of bone soup (p<0.05). The formula of bone soup was studied by the single factor and orthogonal experiment; the results indicated that the sensory quality such as color, viscoelasticity and flavor were improved significantly when the quantities of the chicken, duck meat, pig belly were 60-80g respectively. The studies on different proportions of bone and water suggested that the sensory evaluation score and soluble solid content were maximum when the proportion was 1/2.5-1/3. The studies on different quantities of vinegar indicated that the contents of calcium of bone soup with 6.0ml vinegar was 325.3mg/100g, which was higher than bone soup without vinegar, but the ordinary flavor of bone soup will be changed when the quantity of vinegar exceeded 6.0ml.Secondly, effects of boiling processing of ordinary pressure (95-98℃) and high pressure (121℃) , papain, concentrated processing of ordinary pressure and vacuum were studied. The results of physical and chemical indexes of boiling processing indicated that the soluble solid content, proteide and iodin value in concentraed bone soup by high pressure were higher than ordinary pressure (P<0.05) while the other indexes of ordinary pressure included POV, TBARS, acid value, amino nitrogen, proteolysis index, collagen and free amino acid were higher than high pressure. There were 15 volatility flavors in bone soup by ordinary pressure while the high pressure was only 10. The total sensory evaluation score of boiling processing by the ordinary pressure and high pressure were 23.92 and 21.06, the ordinary pressure was higher than high pressure.The study on boiling temperature by ordinary pressure showed that the soluble solid content was increasing with the temperature raising while the augmentation became slow when temperature got to 95℃. Then, the sensory quality was the best when the temperature was 95-98℃while it began to decline when the temperature exceeded 98℃. The study on the bone soup with papain indicated that the content of free amino acid was the twice of the soup without enzymic degradation. The indexes of the bone soup with enzymic degradation such as smell, taste, acceptability, the proteolysis exponent and total sensory evaluation were higher than the bone soup without enzymic degradation, the difference was notable (p<0.05). It suggested that the papain can promote proteolysis and improve the sensory quality of bone soup. There was no notable difference in synthetic sensory quality between the common concentration and vacuum concentration, but the color of bone soup ofvacuum concentration was milk white, the common concentration was snuff color.The results of study on sterilization and storage were as follows: The best way ofsterilization of the concentrated bone soup was boiled 10-15min in 100℃water. The concentrated soup was stored at 4℃can keep 30d while the storage of normal temperature can only keep 15d. The shelf life can be prolonged from 15d to 30d by BHT and potassium sorbet under the condition of refrigeration. It was shown in this paper that the shelf life can be prolonged by using the aseptic, antioxidant and adopting appropriate sterilization and storage method.It was indicated from our study that the proper proportion of bone and water was 1/2.5-1/3, the optimal quantity of vinegar was 6.0ml and the chicken, duck, pig belly was 60-80g (per 500g of yak bone) respectively. Firstly, the bone was boiled 30min by ordinary pressure in 100℃water; then, boiling 6-8h in 95-98℃; next, concentrating to the third of the raw materials by vacuum concentration and preparing, packing and sterilizing the soup. At last, the soup of yak bone full of unique flavor and nutrition was finished.