Effect of modified celluloses and pectins on farinographic and fermentation parameters of dough

CORREA, J.; AÑÓN M.C; PEREZ G.; FERRERO C.

Madrid - España

Congreso; 13 th ICC Cereal and Bread Congress; 2008

International Association of Cereal Science and Technology

Among additives employed in breadmaking, hydrocolloids can be considered an interesting option, because of their ability to confer different rheological characteristics to dough and to render final products with a higher amount of fiber. In the present work, the effects of different commercial modified celluloses and pectins on farinographic characteristics of dough (water absorption, development time, stability, degree of softening) and the performance during fermentation were analyzed. Gums employed were: microcrystalline cellulose (MCC), carboxymethyl cellulose (CMC),  two different types of hydroxypropylmethylcellulose  (HPMC) and two different types of pectins: high-methoxylated pectin (HMP,  degree of esterification=69%) and amidated low-methoxylated pectin (LMP).  Gums were added at levels ranging from 0.25 to 2 g/100g flour. A commercial flour of medium quality was used. Farinographs were performed on mixtures of flour and hydrocolloid, without and with NaCl (2 g/ 100 g flour). For fermentation assays, fresh yeast (3 g/100g flour) was used; farinographic water absorption and development time were applied to prepare doughs. Farinographic water absorption increased when higher concentrations of hydrocolloid were incorporated; the higher absorptions were observed when the two types of HPMC were used. Values of water absorption were higher in mixtures without NaCl. A linear relationship between the percentage increment in water absorption and the hydrocolloid level was observed within the assayed range of concentrations. The development time was not significantly modified when pectins were added but it significantly increased when modified celluloses were added at 1 and 1.5% levels. In mixtures with NaCl, farinographic stability resulted negatively affected by HPMCs at levels higher or equal to 0.25% depending on type used and not significantly affected by MCC or CMC. A different effect was observed in mixtures without salt: the highest levels of CMC markedly reduced farinographic stability, but this parameter was not affected by HPMCs nor MCC. Pectins affected stability only at the highest concentrations. NaCl act as a water structure reinforcer, thus promoting hydrophobic interactions. So, the more hydrophobic modified celluloses like HPMCs could interact with gluten proteins, rendering in this case a less stable network. In absence of salt, this effect is not observed. On the other hand, the interaction with charged molecules like CMC seems to be favored in the absence of salt. Maximum fermentation volumes were achieved with CMC or HMP addition. The lowest initial slopes of the fermentation curves were obtained when CMC or pectins were added.. However, no tendencies respect to the influence of  the level of gum on this initial stage were found. These results indicate that hydrocolloids significantly affect farinographic characteristics and fermentation performance but the effect may vary not only with concentration and structural characteristics but also when interactions with other components of dough, like salt, may be established.