Research On Factors Affection Physical Properties Of Processed Cheese Spread And Development Of New Products

Processed cheese spreads have the high nutrition, its industrialization is inevitable trend for oureconomy development.Many factors infulence the quality of processed cheese spreads,these factorsinfulence each other, so a lot of unsure factors appear during processing or in the products. Becausethe industrial production experience of processed cheese cannot satisfy the industrialization ofproducts,therefore the scientific research about processed cheesse spreads is the urgent need.Base on these issues,fluid model of processed cheese spreads during processing were studiedin this work.At the same time,finded a new testing mehod of meltability of processed cheese spread,analysised the main factors which infulence the physical properties of processed cheese spreads.and effect of processing conditions on the physical properties of processed cheese spreads were alsostudied.we illuminated the main reason of change of processed cheese spreads at the differentconditins using the protein chemical theory. In the end, we developed two kinds of new products.The results were as follow:(1)apparent viscosity can characterize the rheology propeties well.processed cheese has beenbehaved as a pseudoplastic fluid, power-law model can described this kind of property.Moisturecontent and temperature affected flow behavior index.processed cheese spread tended to have aNewtonian behavior when low moisture content.Temperature had similar effect with moisturecontent on procesed cheese spread viscosity.Regression models were suggested in order to describethe offect of temterature and moisture content on the rheological paramters: n=0.1438+0.825X_w+0.00202T (R²=0.8508)Consistency index was effected by temperature,moisture content and protein content.When thetemperature and moisture content was increased,consistency index was reduced.In contrast,anincrease in protein content leaded to products wht high values of viscosity. Regression models weresuggested in order to describe the effect of temterature,moisture content and protein content on therheological paramters: Lgk=8.98052-0.14607X_w-0.04664T+0.26343X_p (R²=0.9192)Fat did not significantly affect processed cheese spreads apparent viscosity.(2) Physical properities is not correlated with heating physical properity, however, apparentviscosity of processed cheese is correlated with meltability (R²=0.8965), so we can useapparent viscosity express the meltability indirectly.(3)Change of processing conditions can infulence the funtionality and microsturcture of processed cheese spreads:First, the sort and concentration of emulsifying salts:when the concentration fo salts wereincreased, hardness and viscosity of proceseed cheese spreads were increased.when theconcentration of salts were equal,hardness and apparent viscosity of products using the NaP₃O₁₀were higher, chelated ability from high to low is Na₅P₃O₁₀, Na₄P₂O₇, trisodium citrate, Na₂HPO₄,(NaPO₃)_n. We also verified that Salts can enhance emusify ability through enhancing the pH valueand chelated ability.When the concentration of salts were 3ï¼….microstructure of products wereuniformity and close.Second, mature degree of natural cheese:when the matured cheese were increased,hardnessand viscosity were induced.when we use the young cheese to procuce the proceseed cheese,we canfounded that pro-pro interactions were stronger, and hardness and viscisity were higher.when theproportion of natural cheese were 1:1,products were uniformity and close,and they were also stable.Third,pH value:minor variations in pH substantially affented the structure of processed cheesespreads.adjustment of pH values between 5.7～6.1 during the manufacture of processed cheesespreads a regular tridimensional network that entrapped spherical fat particles but avoided proteinaggregation,and increase the water holding capacity of protein. When the pH value was increased,peptization coefficien(chelated ability) was increased (P＜0.01)。Forth,processing conditions:when the tempetature were increased,hardness and viscosity ofproducts were induced.when the shearing rate were increased,hardness and viscosity wereincreased.when the cooking time were 5～20min,hardness and viscisity were increased.the cookingtime exceeded 20min,functionality of procucts were induced.20min of cooking time were thebest,because pro-pro form a stronger gel at this time,hardness and viscosity of products werehigher.Final,cooling method:cooling at the room temperature(solw cooling) can increase the hardnessand apparent viscosity of products,in constract,cooling at 4℃can induce relatively thehardness.when we cooled the products at 4℃,pro-pro cell were thicker, and network were colser, sothey can form a stronger gel structure,increase the hardness and apparent viscosity.Finally, new processed cheese with tastiness of banana and dried fish floss were developed.The product has wonderful taste and nutrition:processing method and the optimum formula of processed cheese containing banana juice wasselected by orthogonal experiment L₉(3⁴): cheese, water (45ï¼…), salt (2.5ï¼…), sugar(7ï¼…), xanthicgum (0.5ï¼…) were melted for 7 min, then mixed the banana juice (30ï¼…) for 5 min, cooled to 4℃the optimum formula of cheese using dried fish floss: cheese, water (45ï¼…), salt (2.5ï¼…),xanthic gum (0.5ï¼…) were melted for 5min, then mixed the dried fish floss (5ï¼…) for 5～7min,cooled to 4℃, Finally, a processed cheese with tastiness of dried fish floss was developed. Theproduct has unique dried fish floss taste and nutrition.