Progress 10/15/01 to 10/31/05
Outputs
Role of calcium on functional, rheological and structural characteristics of Mozzarella cheese was studied. Part skim and fat free Mozzarella cheeses were manufactured respectively from 1.8% fat and 0.05% fat milks by the direct acidification method. Calcium chloride was added into milk to study the effects of colloidal and soluble calcium. Milk was preacidified to four levels (no change in control, pH 6.2 in T1, pH 5.9 in T2 and pH 5.6 in T3). The cheeses were stored at 4 C until evaluation of various characteristics on d 1, 7, 15 and 30. Part skim Mozzarella cheeses were evaluated for chemical (moisture, fat, protein, salt, ash, calcium and soluble nitrogen), functional (softening time-temperature, melting time-temperature, melt area, flow rate, extent of flow and stretchability), rheological (viscoelasticity), and structural characteristics. Regression and neural network models correlating calcium concentrations and various properties of cheeses were developed. The
results revealed that soluble calcium did not affect the functional properties to a greater extent. Lowering of micellar calcium increased the melt area, flow rate and extent of flow but reduced the softening and melting time and softening temperature of part skim Mozzarella cheese. Reducing 25, 35, and 45% levels of calcium increased the melt area of part skim Mozzarella cheese by 1.4, 2.1, and 2.6 times, respectively, on d 1 of manufacture. Low calcium cheeses (both, part skim and fat free) required less time to soften and melt, flowed faster and had greater extent of flow than control. Reduction of 35 % of the calcium in fat free cheese increased the flow by 2.5 times and these cheeses required 19 % less time to melt. Opacity decreased when calcium was lowered in fat free cheeses. Higher proteolysis at a faster rate was also observed in both (part skim as well as fat free) cheeses. Refrigerated storage also increased flow rate, extent of flow, and soluble nitrogen and lowered
softening and melting times in all the cheeses. Storage also resulted in increase in melt area of part skim Mozzarella cheese. Reduced calcium part skim Mozzarella cheeses had 5 to 10 times higher elongation and required 33 to 45% less force to stretch as compared to control on d 1. Low calcium cheeses (0.35% in T3 vs. 0.65 % in control) had lower values of elastic (0.83 MPa vs. 1.89 MPa) and viscous moduli (0.57 MPa vs. 1.43 MPa). After 30 days of storage, the elastic modulus of the control and T3 cheese declined from 1.89 MPa to 1.69 MPa and from 0.83 MPa to 0.55 MPa, respectively. Similar reduction in viscous modulus of control and lowest calcium cheeses (T3) was also noticed. Reduced calcium cheeses had more hydrated protein matrix with greater number of fat particles (control = 125, T1=193, T2= 184 and T3= 215 with SEM and control = 86, T1=87, T2= 125 and T3= 140 with CLSM). Regression analysis revealed that 57, 52, 66, 74, 67 and 53% variation, respectively, in melt area,
softening temperature, softening time, melting time, flow rate and extent of flow could be explained as a function of calcium concentration of part skim Mozzarella cheese.
Impacts
The above characteristics of Mozzarella cheese were more affected by calcium reduction as compared to storage. Overall, it was concluded that Mozzarella cheeses with reduced calcium concentration had increased meltability and stretchability on d 1. Improved softening, melting, stretching and flow properties of low calcium Mozzarella cheeses is a clear advantage to cheese manufacturers and end users as they may not have to wait 15 to 20 days for proteolysis of cheese to obtain desired melt properties. Hydrated protein network and better emulsified fat in low calcium cheeses were attributed for improved properties of Mozzarella cheeses.
Publications
- No publications reported this period
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Progress 01/01/04 to 12/31/04
Outputs
Correlation and regression analyses of calcium concentration and rheological characteristics in Mozzarella cheese were studied. Part skim and fat free Mozzarella cheeses were manufactured on four separate occasions. Calcium concentration in both types of cheeses was manipulated at 4 different levels. Rheological characteristics such as melt area, softening, melting and flow were studied on d 1, 7, 15 and 30. The results revealed that 57, 52, 66, 74, 67 and 53% variation, respectively, in melt area, softening temperature, softening time, melting time, flow rate and extent of flow could be explained as a function of calcium concentration of part skim Mozzarella cheese. Calcium concentration explained 50, 61 and 43% variation, respectively, in melting time, flow rate and extent of flow, but poor correlation existed between calcium concentration and melt area, softening and melting time-temperatures of fat free Mozzarella cheese. Calcium concentration, among all
compositional parameters, was highly correlated with rheological characteristics of Mozzarella cheeses. Calcium concentration was also one of the major predictor variables in regression models, which were developed to decide the rheological characteristics of Mozzarella cheese. Based on the above correlation the cheese industry can develop a strategy to obtain specific characteristics in Mozzarella cheese for varied applications in the food systems.
Impacts
Outcome of this study not only highlights correlation of calcium in deciding cheese functionality but also establishes the important changes occurring in molecular level of the Mozzarella cheese. These results will allow cheese manufacturers to produce a product designed for aspecific market. The final outcome of this study will help scientific community understand the role of calcium in functional and structural characteristics of Mozzarella cheese.
Publications
- Joshi, N. S., K. Muthukumarappan, and R. I. Dave. 2004. Viscoelastic properties of part skim Mozzarella cheese: effect of calcium, storage and test temperature. International J. Food Prop. 7(2): 239-252.
- Joshi, N. S., R. I. Dave, and K. Muthukumarappan. 2004. Modeling rheological characteristics and calcium of Mozzarella cheese. J. Food Sci. 69(3): 97-101.
- Joshi, N. S., K. Muthukumarappan, and R. I. Dave. 2004. Effect of calcium on microstructure and meltability of part skim Mozzarella cheese. J. Dairy Sci. 87: 1975-1985.
- Joshi, N. S., K. Muthukumarappan, and R. I. Dave. 2004. Effects of reduced-calcium, test temperature and storage on stretchability of part skim Mozzarella cheese. Australian J. Dairy Technol. 59(1): 60-65.
- Muthukumarappan, K., N. Joshi, and R. I. Dave. 2004. Effect of calcium on functionality of Mozzarella cheese made from skim milk. Proceeding of the 9th International Conference of Engineering and Food (ICEF9), March 8-11, 2004, Montpellier, France, SCI Publication, pp 374-379.
- Vykundeshwari, G, N. Joshi and K. Muthukumarappan. 2004. Correlating Calcium Concentration and Rheological Characteristics of Mozzarella Cheese Using Neural Network. Paper No: 046044. Proceedings of the 2004 ASAE/CSAE International Meeting, August 1-4, 2004, Ottawa, Canada.
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Progress 01/01/03 to 12/31/03
Outputs
This research project is aimed to study the role of calcium on functional (melting and stretching) and rheological properties of part skim Mozzarella cheese. We also proposed to study the changes taking place in fat and protein of the cheese at molecular level by studying structural characteristics of these cheeses. Effects of calcium, test temperature and storage on stretchability of part skim Mozzarella cheese were evaluated. Part skim Mozzarella cheeses containing different calcium levels (control=0.62, T1=0.51, T2=0.45 and T3=0.35%) were manufactured by direct acidification method. A specially designed double walled apparatus was used to evaluate the uniaxial horizontal extension of cheese. Stretchability, in terms of maximum force required to stretch, and elongation at break were evaluated at 30, 35 and 40 C temperatures of cheese on d1 and d 30. On d 1 of manufacture, the reduced calcium cheeses had 5 to 10 times increased elongation and required 33 to 45% less
force to stretch as compared to the control; the elongation and force were dependent upon calcium level of cheese and test temperature. Stretchability at 30 and 35 C had little effect on elongation; however, at 40 C there was a dramatic increase in elongation properties of the cheese. T1 (0.51% calcium) and T2 (0.45% calcium) cheeses elongated 14 and 12 times more at 40 C as compared to 30 C. The cheeses required 33 to 44% less force at 40 C as compared to at 30 C. Storage of 30 days caused up to 50% reduction in force required to stretch the cheese; however, no effect of storage on elongation of the cheeses was observed. Overall, it was concluded that cheeses with reduced calcium concentration had increased stretchability at 40 C on d 1.
Impacts
Outcome of this study not only highlights correlation of calcium in deciding cheese functionality but also establishes the important changes occurring in molecular level of the Mozzarella cheese. These results will allow cheese manufacturers to produce a product designed for aspecific market. The final outcome of this study will help scientific community understand the role of calcium in functional and structural characteristics of Mozzarella cheese.
Publications
- Joshi, N. S., K. Muthukumarappan, and R. I. Dave. 2003. Understanding the role of calcium in functionality of part skim Mozzarella cheese. J. Dairy Sci. 86(6): 1918-1926.
- Joshi, N. S., K. Muthukumarappan, and R. I. Dave. 2003. Effect of calcium on physico-chemical properties of fat free Mozzarella cheese. J. Food Sci. 68(7): 2289-2294.
- Joshi, N.S., K. Muthukumarappan and R.I. Dave. 2003. Changes in microstructure of part skim Mozzarella cheese as a function of calcium. American Dairy Science Association, annual meeting, June 22-26, 2003. Phoenix, AZ. Technical Program Abstract.
- Joshi, N.S., R.I. Dave, and K. Muthukumarappan. 2003. Effect of calcium on functionality of fat free Mozzarella cheese. American Dairy Science Association, annual meeting, June 22-26, 2003. Phoenix, AZ. Technical Program Abstract.
- Joshi, N.S., K. Muthukumarappan and R.I. Dave. 2003. Role of calcium in stretchability of Mozzarella cheese. Institute of Food Technologists annual meeting, July13-16, 2003, Technical Program Abstract 14A-15, Chicago, IL.
- Joshi, N.S., K. Muthukumarappan and R.I. Dave. 2003. Modeling the effects of calcium and compositional parameters on melt characteristics of Mozzarella cheese. ASAE-CSAE north central intersectional conference. Fargo, ND. October 3-4, 2003.
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Progress 01/01/02 to 12/31/02
Outputs
This research project is aimed to study the role of calcium on functional and rheological properties of part skim Mozzarella cheese. We also proposed to study the changes taking place in fat and protein of the cheese at molecular level by studying structural characteristics of these cheeses. We made part skim Mozzarella cheese from pasteurized milk (1.8 % fat) pre acidified at different pH (control =no treatment, T1 =pH 6.2, T2 = pH 5.9 and T3 = pH 5.6) with citric and acetic acids to obtain various calcium levels in the cheeses. The cheeses were made by direct acidification method using glucono-delta-lactone. Measures were taken to keep uniform moisture content in the cheeses. After draining the whey at pH 5.1, the curd was dry salted at 2% and stretched at 77 C in 5 % brine. The cheese blocks were cut in to 4 parts, individually vacuum packaged and stored at 4 C until analysis on d1, 7, 15 and 30. The cheeses were subjected to compositional analysis (moisture, fat,
protein, salt, ash and calcium) and various functional as well as rheological parameters such as melt area, softening and melting time and temperatures, flow rate, extent of flow and viscoelasticity (elastic and viscous moduli) were studied. Extent of proteolysis was studied by determining soluble nitrogen. The cheeses microstructure using scanning electron microscopy (SEM) was studied. Changes taking place in the above properties during refrigerated storage were also studied. The data were statistically analyzed using PROC GLM and PROC MIXED procedures of SAS. The results demonstrated that preacidification of milk significantly reduced the calcium content (control=0.65 %, T1=0.48%, T2= 0.42 % and T3=0.35%) whereas, rest of the components (except ash) remained in all the cheeses. With reduction in calcium there was great improvement in softening, melting and flow behavior of the cheeses. T3 cheeses had more melt area (258%), higher extent of flow (36%) and flowed with higher rate
(108%) as compared to control. These cheeses softened and melted at lower temperatures (18 and 5 % respectively) and required less time to soften and melt (30 and 29 % respectively) as compared to control. Soluble nitrogen in T3 was significantly higher (0.77 %) than control (0.40 %). Calcium level alteration was significantly correlated with elastic as well as viscous moduli of the cheeses. The values of elastic and viscous moduli in control and T3 were respectively 1.88 and 0.83 MPa and 1.43 and 0.57 MPa). Refrigerated storage of all the cheeses resulted in increased in melt area, flow rate, extent of flow, and soluble nitrogen, and decrease in time required to soften and melt and visco-elasticity moduli. The microstructural study indicated that more numbers and uniform arrangement of the fat globules in the protein matrix upon reduction of calcium in the cheese. These results further supported our hypothesis that casein in a reduced calcium cheese is better able to emulsify the
fat.
Impacts
Outcome of this study not only highlights correlation of calcium in deciding cheese functionality but also establishes the important changes occurring in molecular level of the Mozzarella cheese. These results will allow cheese manufacturers to produce a product designed for aspecific market. The final outcome of this study will help scientific community understand the role of calcium in functional and structural characteristics of Mozzarella cheese.
Publications
- Joshi, N. S., K. Muthukumarappan, and R. I. Dave. 2002. Role of soluble and colloidal calcium contents on functionality of salted and unsalted part skim Mozzarella cheese. Australian J. Dairy Technol. 57:203-210.
- Joshi, N.S., K. Muthukumarappan and R.I. Dave. 2002. Effect of calcium on dynamic rheological properties of Mozzarella cheese. ASAE-CSAE north central intersectional conference. Saskatoon, Canada, September 27-28, 2002.
- Joshi, N.S., K. Muthukumarappan, R.I. Dave and A.K. Mahapatra. 2002. Development of a stretch test for Mozzarella cheese. American Society of Agricultural Engineers (ASAE) Annual International meeting / International Commission of Agricultural Engineering (CIGR) World congress, paper No. 026149, Chicago, IL, USA.
- Joshi, N., K. Muthukumarappan and R. I. Dave. 2002. Role of calcium on dynamic rheological properties of part skim Mozzarella cheese. Institute of Food Technologists' Annual meeting, June 15-19, 2002, Anaheim, CA, Technical Program Abstract, p. 22.
- Joshi, N.S., K. Muthukumarappan and R.I. Dave. 2002. Role of calcium in microstructure of part skim Mozzarella cheese. 93rd American Oil Chemists' Society (AOCS) annual meeting, May 5-8, 2002, Montreal, Canada.
- Joshi, N., K. Muthukumarappan and R. I. Dave. 2001. Role of calcium in the functional and rheological properties of Mozzarella cheese. Institute of Food Technologists' Annual meeting, New Orleans, LO, June 23-28, 2001, Technical Program Abstract, p. 209-210.
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