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Effect of processing variables on viscoelastic properties and textural attributes of heat-acid coagulated milk product paneer.

S. Hussain

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06-24-2020

Abstract:

304
Effect of processing variables on viscoelastic properties and textural attributes of heat-acid coagulated milk product paneer.
S. Hussain*1, P. Sharma2,3, S. Hogan2. 1ICAR-National dairy research Institute Karnal, Haryana, India, 2Teagasc Food Research Centre Moorepark, Co. Cork, Ireland, 3Utah State University Logan, UT.

Paneer, a popular unripened soft cheese of India, is prepared by heat and acid coagulation of milk. The study investigated the effect of milk heating (90�C/no hold and 90�C/10 min) and coagulation temperature (70, 80 and 90�C) on structure, texture and rheological properties of paneer. Paneer structure was observed using confocal laser scanning microscopy. Textural attributes were determined using a texture analyzer. Viscoelastic properties i.e., storage modulus (G') and loss modulus (G”) were measured using a frequency sweep test. Transient rheological responses of paneer under constant stress (50 Pa) and strain (1%) were measured using creep compliance and stress relaxation tests, respectively. Moisture content decreased in paneer samples with increasing milk coagulation temperature (~50.8% and ~45% wt/wt at 70�C and at 90�C coagulation, respectively). Hardness, chewiness and storage modulus (G') values of paneer samples increased with an increase in coagulation temperature. Paneer, coagulated at 90�C, exhibited highest hardness (4.24 � 0.05 g; heat treatment to 90�C/no-hold) and chewiness (1.65 � 0.09 g; heat treatment 90�C/10 min) values when compared with other treatments. However, milk heating conditions had no significant (P < 0.05) effect on creep parameters indicating better structure retention in samples coagulated at 90�C (lower deformation rate) and weak structure in samples coagulated at 70�C (higher deformation rate). Stress relaxation was also slower when paneer prepared at lower coagulation temperatures indicating that increase in coagulation temperature from 70 to 90�C resulted in more elastic paneer. Confocal laser scanning microscopy revealed that increasing coagulation temperature resulted in samples with a more compact and dense protein matrix. Higher total solids content and lower moisture content of paneer samples were associated with firmer texture and denser protein structure which could be attributed to increased coagulation temperatures. The present study offers insight into the effects of processing conditions on the intricate relationships between structure-rheology-texture and functionality of paneer.

Keywords: structure, rheology, paneer.

Biography: Dr. Shaik Abdul Hussain is working as scientist in Dairy Technology department at National Dairy Research Institute. His interests include functional proporties of dairy products.