Application Of Freeze Concentration In The Recycling Of Meatballs Boiled Liquid

The boiled liquid of pork meatballs is rich in protein,amino acids, fats and other nutrients. In order to carry out its applications of reclamation and condensation, this article used homemade suspended-type freeze concentration equipments to concentra- te the boiled liquid of pork meatballs, studied the factors which affect freeze concent- ration effects were searched. Comparison experiments with traditional methods of high temperature evaporation and vacuum evaporation were carried out. Further researches on how meatball boiled liquid can improve meatball quality were also performed. Specific conclusions are as follows:(1) The best coolant temperature of the freeze concentration is -21～-24℃, in this temperature, the concentration ratio reaches 1.63, time for concentration is short and the final concentrate value is high, which make it easy to achieve the objects; Purity of ice crystal of suspended-type freeze concentration was obvious higher than progressive freezing concentration, and the ice crystal were easier to separate; Pre-cooling can effectively raise the speed and purity of ice crystal, the best pre-cooling temperature of concentration is 3℃.(2) Multi-level freeze enrichment of meatball liquid can effectively raise the solution's concentration. LevelⅠfreeze concentration raised the solution concentration from 2.75% to 6.60%, LevelⅣfreeze concentration raised the solution concentration to 21.3%. So multi-level enrichment is better than single-level enrichment.(3) Comparison experiments of meatball boiled liquid among freeze concentration, high temperature evaporation and vacuum evaporation showed that protein, free amino acids and fat content are close to each other, but the first method was better than the others on solution color, turbidity, odor and taste, and most close to the untreated solution.Cost of freeze concentration is also lower than high temperature evaporation and vacuum evaporation; (4) Samples of meatballs with concentration liquid and without concentration liquid were compared. Results showed that the two samples had the same moisture absorption and texture, but the protein content of former sample increased from 11.93% to 12.39%, brittleness organizational improved flexibility, taste score increased from 54.5 to 77.5. As a result, quality of the meatball is improved.(5) One of the concentration's by-product is oil. The physical and chemical analysis of oil showed that: the acid value was 1.3 mg/g; the peroxide value was 0.14 g/100g; the oil had no off-flavor but heavy smell of lard, cooking oil quality indicators are in line with national standards to be recycled. Boiled liquid of pork meatball's COD value was 19.4 g/L, ammonia nitrogen was 42 mg/L, nitrate nitrogen (N total) is 7.6 mg/L, pH = 5.0, exceeding the national integrated wastewater discharge standard.