Influence of some preservatives on cast uf-white soft cheese properties during cold storage [electronic resource].

Includes references.

The aim of this work was planned to study the effect of formaldehyde (FA) and hydrogen peroxide (H₂O₂) on the properties of UF cheese made without whey drainage. Cast UF-white soft cheese was made using precheese spiked either with FA or H₂O₂at the level of nil or 0.3% whether further heat treated at noc for 20 sec. after preservative adding or not. The resultant cheese was kept at SoC for 4 weeks (W).The obtained results indicated that, neither dry matter (OM), fat/DM, proteinIDM nor ash content of cheese was significantly affected by the kind of the preservative added. However, the fat/DM, as well as the ash contents raised and that of protein IDM decreased due to the further heat treatment of the precheese after preservative adding prior cheesemaking. The water soluble nitrogen/total nitrogen and pH value of cheese lowered by FA than H₂O₂. While, the titratable acidity of cheese increased in the presence of FA than H₂O₂. Considerable depressing in the absorbancy of most proteins fractions especially B-lactoglobulin, (P-Lg) gained by Sephadex GIOO due to precheese treating either by H202 adding or further heating, opposite to that occurred when FA was added, which inhibited the heat-induced dissociation of casein (Cn) contributed to the further heating of precheese. While, H202 retarded but did not completely prevent the heat-induced association between k-Cnand P-Lg. Except of a.l-Cn, the levelof a.2-Cn, p-Cn, k-Cn and' y-Cns of cheese protein fractionated by sodiumd odecyl sulfate-polyacrylamide gel electrophoresis (SDS-P AGE) were increased by FA and decreased by H202 as compared with the control. However, the level of lactoferrin (placed also with the cheese ripening proteinous product of 0..-1ragment), immunoglobulins (Igs), p-Lg and a-Iactoalbumin (a-La) ofUF cheese ptotein were raised by adding H202 to precheese as'compared either with thosecontaining FA 9fcven the control. The precheese further heating led to peakdiminishing 9fmost whey protein fractions (except of those ofIgs and a-La), a.:Cn as weU/'as ~-Cn and increasing in both of k-Cn and y-Cns peaks. The prolonging of cheese cold storage period was associated with decrement in all.

Summary in Arabic.

1