RESUMEN
The preservation of mould-ripened salami was investigated during 48 days at 19-20 °C under different packaging conditions: (i) high barrier film filled with air, 100% N2 or under vacuum, (ii) biaxially oriented polypropylene film, (iii) microperforated polyethylene film and (iv) unpackaged. Sensory, texture profile, physicochemical and microbiological analyses were performed. Fungal quantification revealed two data groups. In group 1 (consisting of salami in microperforated polyethylene film, biaxially oriented polypropylene film and unpackaged) the conidium viability was relatively constant. In group 2 (salami preserved in high barrier film filled with air, 100% N2 or under vacuum) the conidium viability decreased due to the absence of oxygen and the high carbon dioxide volume fraction. SEM micrographs showed micromorphological changes in fungal structure; microperforated polyethylene film, biaxially oriented polypropylene film and unpackaged conditions preserved the conidial morphology, while high barrier film filled with air, 100% N2 or vacuum conditions collapsed the hyphae and most of the conidia. Salami packed in microperforated polyethylene film and biaxially oriented polypropylene film showed the most acceptable organoleptic characteristics and lower hardness and chewiness values after packaging.
RESUMEN
The present study compares the emulsifying properties in acidic conditions of hull soluble polysaccharides (HSPS), soybean soluble polysaccharides (SSPS) and its mixtures. These fractions were obtained from byproducts of soybean processing industry (soy hull and residual fiber after isolation of soy cotyledon protein, respectively). Although SSPS is already characterized, HSPS is a novel fraction which has not been studied in deep and it is still unexplored as emulsifier. Dispersions of both fraction and a mixture 50:50 of them at pH 3.0 were used as aqueous phase (1.0-3.0 % w/w) in coarse and fine oil-in-water emulsions (oil mass fraction = 0.3). Its stability was evaluated through the evolution of backscattering profiles (%BS), particle size distribution and mean particle diameters. The rheology of the emulsions was also analyzed. Both fractions provided stability to creaming when increasing the polysaccharide concentration and energy of homogenization. While coarse emulsions were unstable systems, fine emulsions were stable enough and allowed a deeper analysis of the destabilizing processes. A bridging flocculation phenomenon in the presence of HSPS and HSPS/SSPS mixtures is suggested, which influences the creaming and rheological behavior. Also, coalescence index increases according HSPS and HSPS/SSPS concentrations, but particle sizes reached were smaller than in SSPS emulsions. Fine emulsions with 3 % of HSPS/SSPS mixtures yielded the best results on the overall stability at 28 days. So, functional properties of the fractions may improve by the formulation of emulsions consisting in mixtures of them. These results are of interest to the manufacturing of acidic foods, taking advantage of obtaining byproducts from residual materials.