Microstructure and textural properties of Kareish cheese manufactured by various ways

Abstract

Kareish cheese was made from skim buffaloes’ milk. The effect of the way used in milk coagulation on the microstructural (monitored using scanning electron microscopy) and textural (measured by Emperor ™Lite) properties, as well as chemical, bacteriological and sensory characteristics of the resultant fresh Kareish cheese was studied. Four treatments of Kareish cheese were made by applying coagulation starters of CH-1 (containing of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) (T1) and ABT-1 (containing of Lb. acidophilus, Str. thermophilus and bifidobacteria) (T2), in addition to use the previous starters with rennet (T3 and T4, respectively) during the cheese-making. Significant differences (p⩽0.05) between cheese treatments affected by the type of starter and way used in milk coagulation were observed. Kareish cheese made with starter and rennet (T3) and (T4) was characterised by low contents of fat in dry matter, total protein, ash and pH values, as well as low counts of bacterial starter cells, but high contents of moisture and salt in water phase; as compared with cheeses with starter only (T1 and T2). Also, starter cells of Str. thermophilus were prevalent in all cheese treatments, followed by cells of Lb. delbrueckii ssp. bulgaricus (T1 and T3), Lb. acidophilus and bifidobacteria (T2 and T4), respectively. The textural characteristics were revealed that the hardness and gumminess negatively correlated to cohesiveness and springiness. Kareish cheese made with starter and rennet (T3 and T4) had the lowest hardness, gumminess and chewiness values, but the highest values of cohesiveness and springiness. Micrographs were shown contained (T1) and (T2) cheeses on cluster bacterial starter cells. Also, protein aggregates and voids were observed in micrographs of (T3) and (T4) cheeses made with rennet and different starter strains (not shown). Sensory evaluation showed that Kareish cheeses made with different starters and rennet were more accepted by the panellists than with starters only.