Physicochemical and textural properties of mozzarella cheese made with konjac glucomannan as a fat replacer

Konjac glucomannan (KGM) is a natural polysaccharide with several favorable nutritional characteristics, and exhibits functional properties as a potential fat-replacer in dairy products. In our study, composition, color and browning (L*, a* and b* before and after heating), and textural characteristics of low-fat and skimmed Mozzarella cheese with KGM (LFKGM and SKKGM) were compared with those of full-fat, low-fat and skimmed Mozzarella cheese controls (FFC, LFC and SKC) after 0, 7, 14, 21 and 28 days of storage at 4 degrees C. In general, LFKGM and SKKGM had similar composition to LFC and SKC, respectively, except that LFKGM had higher moisture than LFC and SKKGM had high a(w) than SKC. The LFKGM and SKKGM had higher L* (lightness) than LFC and SKC, respectively, and LFKGM had similar whiteness to FFC before and after heating. However, the browning factor was not affected by KGM addition. The a* values (greenness) of LFKGM and SKKGM were more negative than for LFC and SKC before and after heating. The b* values (yellowness) of LFKGM and SKKGM were higher than LFC and SKC, respectively. Grated SKKGM exhibited lower firmness than SKC, and LFKGM exhibited higher stickiness than LFC. The melted LFKGM and SKKGM had similar resistance and stretch quality to LFC and SKC when they were stretched, respectively. The changes in the lightness, moisture and firmness as affected by KGM addition in the cheeses were more close to those of full-fat cheese compared with the cheeses without KGM, indicating KGM would be a potential fat replacer to be used in Mozzarella cheese.