Modifying textural and microstructural properties of low fat Cheddar cheese using sodium alginate

Low fat Cheddar cheese (LFC) with up to 91% fat reduction were prepared using four levels of sodium alginate (alginate): 0.12 (LFCA1), 0.17 (LFCA2), 0.18 (LFCA3) and 0.23% (w/w) (LFCA4). Control full fat cheese (CFFC) and control low fat cheese (CLFC) were used for comparison. Physical characteristics, namely texture profile, microstructure, transverse relaxation time (T2) distribution (measured by low-field NMR) and color were analysed periodically during ripening until 180 days. Texture profile analysis illustrated a significant improvement in texture of alginate added LFC (P < 0.05) as compared to CLFC. The textural attributes of LFCA1 ripened for 30 days were comparable to CFFC ripened for 60 days and beyond. A close resemblance in textural attributes between alginate added LFC and CFFC, not previously reported when using other fat replacers, was observed. Scanning electron micrograph (SEM) images revealed that alginate added LFCs had smoother surfaces as compared to CFFC and CLFC, and the dense and compact protein matrix characteristic of CLFC was not observed. Confocal laser scanning microscopy (CLSM) suggested that the fat particle size, area and volume were affected in all LFCs due to their lower fat level and these parameters increased during ripening in CFFC. NMR results revealed increase in higher mobility water fraction in alginate added cheese compared to CFFC and CLFC. Hunter L, a and b values for alginate added LFCs indicated that they were whiter than CLFC and less yellowish than CFFC at the beginning of ripening; the color of some of the alginate added LFCs was comparable to CFFC after 120 days of ripening. Overall, addition of alginate significantly improved the textural, microstructural properties and color of LFCs, affirming its potential as a promising texture modifier.