Production and characterization of bacterial coagulants as calf rennet replacer for Egyptian cheese making.

The bacterial coagulant as calf rennet replacer was aimed to evaluate. The productivity and milk clotting activity [MCA] of coagulants of 12 strains of B. subtilis and 9 strains of B. megaterium were screened. Specific activities of coagulants were tested whether in the crude or in the purified form. The chemical, physical, microbial and organoleptic properties of Ras cheese slurry, coagulum and Domiati cheese [from conventionally salted milk] made with bacterial rennet [concentrated by dialysis against polyethelenglycol 40%] were investigated. Five strains of B.subtilis and three strains of B.megaterium produced milk clotting enzyme [MCE] with MCA> 100 SU/mI, after incubation for 7 days at 30°. The max. relative MCA was recorded at milk temperature of 65° for both types of bacterial rennet in the crude form and increased to 75° [B.subtilis] or 80° [B.megaterium] when purified. While the purification did not change the sensitivity of bacterial coagulants to NaCI or CaC1[2] concentration, where the former salt inhibited while the latter one improved the MCA. The purified enzyme of B.megaterium exhibited higher km and lower Vmax than those occurred by that of B.subtilis.Ras cheese slurry made with B.subtilis rennet matured after 5 days of incubation at 37° and was slightly higher in the flavour score than that of B.megaterium. Both slurries of bacterial rennet possessed a stimulating effect on the growth of the starter cultures added. Bacterial rennet coagulum was softer and synersed lower whey amount than that of calf rennet. Bacterial rennet had also an accelerating effect on Domiati cheese ripening as appeared from the ripening indices determined. Some weakness in the consistenôy associated with Domiati cheese made with bacterial rennet but the flavour score was better after one month and then slightly lowered after two months than the control pickled for the same period

Production of aromatic recombined butter by using different milk solids not fat ingredients

The aim of this study to investigate the possibility of producing aromatic and palatable recombined butter by using ultra filtration whey protein concentrate [UEWPC] as milk solids not fat [MSNF] ingredient instead of dried skim-milk powder [SMP]. Six treatments were formulated in two groups. The first group contained skim-milk powder reconstituted [RSM] with water at ratios of 1:8, 1:7, 1:6, 1:5. The second group contained UF-WPC with 10 and 15% total solids respectively. All treatments were inoculated with [2%] of streptococcus Lactococcus lactis subsp. diacetylactis, and incubated for 24 hr at 30°C. The fermented products were separately used as MSNF ingredients for making recombined butter, which were formulated to contain 80% at, 1.5% salt 0.5% stabilizer and 0.5% emulsifier. The results shoed that the growth rate of L. lactis subsp. diacetlactis increased significantly [p<0.01] with increasing the dry matter content whether of RSM or UF-WPC. Also the starter culture grew more rapidly in UF-WPC than in the RSM. Likewise the production of acetaldehyde increased proportionally [P<0.01] with increasing dry matter used did not result in any significant difference in the chemical composition of the resultant butter. However, in the case of using UF-WPC, the corresponding differences affected significantly [P<0.05] the protein and lactose content of the butter. The peroxide value [PV] of UF-WPC butters was slightly higher than those of RSM butters whether fresh or after refrigerated storage. Organoleptically the presence of UF-WPC obviously improved the flavour and consistency of the butter. Moreover, rheologically, the yield value was lowered, and hence the spreadabilits was improved due to the presence of UF-WPC. The consistency coefficient was not affect by the source of MSNF ingredient studied

Ultrafiltration whey protein concentrate as a substitute for egg white in pie topping meringue

The suitability of ulatrafiltration whey protein concentrate [UF-WPC] as a partial or total replacement of egg white [EW] in meringue making was studied. Fresh EW was proportionally substituted with 25, 50, 75, or 100% [w/w] of UF-WPC, which was previously adjusted to pH 9.5 using NaHCO[3] or Na[2]CO[3], warmed indirectly to 60°C and cooled to the room temperature [22 +/- 2°C], Mixes were then whipped at the highest speed, After one minute, the beater was adjusted to the lowest speed during which hot [100°C] vitreous sugar syrup [VSS] containing 64,5% sucrose and 0,03% Na citrate was slowly added at the rate of 250g to 100g whipped mix followed by adding 0,01g vanilla powder. Foaming power [FP] and foam stability [FS] of whipped mixes [without VSS] were determined at room temp. Final product [meringue] was examined for the organoleptic properties as well as leakage and slipping rated during cold storage [5°C] Higher levels of replacements were associated with increase in [FP] and decrease in [FS] of mixes. While the presence of UF-WPC led also to a relative decrease in the leakage property, the slipping property increased. Replacements over 25% and 75% of UF-WPC alkalized with Na[2]CO[3] and NaHCO[3] respectively were associated with a bitter chalky flavour. The study showed the value of using UF-WPC in the confectionery industry. Whey proteins are available for making food foams, especially when some of the SS-groups are reduced and hydrophobic sites become accessible. Studies claim that, it may be difficult but not impossible, to prepare a substitute for ovomucin [the main protein component of egg white in foam forming and stabilization] from whey proteins [De Wit, 1985] The suitability or utility of when or its concentrates as a partial or total replacement of whole egg or egg white in various food products were reported by many authors [Lovachev et al., 1982, Mann, 1982 and Nakai and Licahn, 1985] Soft meringue, which is usually used as pie topping could be made by whipping the egg white alone and stabilizing the foam white hot vitreous sugar [Felt et al., 1956] Therefore the present study was aimed to use UFWPC in meringue manufacture as egg white substitute