Soluble fibre could boost cheese making

Such fundamental research could eventually lead to improved production and enhanced nutritional content of the resulting cheese. "The incorporation of soluble dietary fibre into cheese may result in the development of both a nutritionally and technologically superior product," wrote lead author Colette Fagan in the Journal of Food Engineering (Vol. 77, pp. 261-268). In Europe and Japan, soluble fibre has the greater market share than insoluble. In the US, where the entire fibre market was worth $192.8m (€151.0m) in 2004, insoluble fibre dominates the market with $176.2m (€138.0m), and $16.6m (€13.0m) soluble. But while Frost and Sullivan predicts overall growth in the US to $470m (€369m) by 2011, the soluble fibre sector is expected to increase by almost twice the compound annual growth rate (CAGR) compared to insoluble fibre - 26.3 per cent compared to 13.1 per cent. The researchers, from University College Dublin and Massey University in New Zealand, measured the effect of adding one of three different soluble dietary fibres (SDF) - gum acacia, inulin, and pectin - on the coagulation kinetics of skimmed milk (provided by Glanbia Dairies). "The results showed that the incorporation of either fibre source significantly affected rennet induced milk coagulation kinetics. However the level and significance of these changes depended on the fibre ingredient added," said Fagan. The authors found that addition of gum acacia (1 per cent) significantly improved milk coagulation kinetics (gelling time) and firmness. The gum acacia fortified samples are reported to have formed firmer gels than the unfortified control samples. Pectin also had significant effects on the coagulation kinetics (gelling time) and firmness, but less marked than gum acacia. Adding 0.2 per cent pectin resulted in rapid development of the gel, comparing favourably with the 1 per cent gum acacia. Inulin however required significantly longer times for gel formation. Gel firmness was also less affected by inulin than for the other two soluble dietary fibres. "The large reduction in coagulation parameters observed when gum acacia was added is due to the ability of this hydrocolloid to form highly tangled polymer gel systems to support the casein matrix," explained Fagan and her colleagues. Milk coagulation occurs by enzymatic hydrolysis of casein, which results in destabilisation of the colloidal system and the formation of protein micelles. These micelles form aggregates, then a matrix and eventually a gel. "How a fibre ingredient interacts with the casein matrix will be critical in determining the acceptability and feasibility of such a product," wrote Fagan. Fagan told FoodNavigator.com that the study merely provides preliminary findings on the effect on SDF on coagulation kinetics. When asked if such techniques could lead to increased cost efficiency and nutritional content of cheeses, Fagan said that more study was needed. "Additional investigation is required on the impact of SDF on the entire manufacturing process as well as on the final product quality, including the effect on texture, flavour and compositional parameters," she said. "We hope to continue research in this area and to be able to answer such questions in the future." And the research has the potential added bonus of the nutritional benefits accorded by using soluble dietary fibre. "Although the demand may be increasing for functional foods, their acceptability by the consumer is still based on satisfactory textural and sensory attributes," said the researchers.

Soluble fibre could boost cheese making

Adding soluble fibres, guar gum and pectin, to skimmed milk could speed up the coagulation time, improving cost efficiency, and impart nutritional benefits, say Irish researchers.

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