Rennin production from microorganisms
2001
Barraquio, V.C.L. | Arganosa, F.C. | Orillo, C.A.
Two hundred and twenty-nine cultures of fungi and 313 cultures of bacteria isolated from samples of soil, mud, manure, decaying fruits and vegetables, and moldy cheese and cream were tested for milk-clotting activity. None of the bacterial isolates were found to be milk-clotting but 15 of the fungal isolates, which were also obtained from the soil, showed milk-clotting activity. The enzyme activity of the calf rennet extract (40-50 g/1000 ml) was significantly higher than any of the fungal rennets (20 g/100 ml). Cheeses made from fungal and calf rennet extracts were evaluated for appearance and color, body and texture, flavor and general acceptability. Analysis of variance for all the sensory scores showed highly significant differences among the 16 cheses (15 experimental and 1 control). However, cheeses 5 and 9 from fungal rennet and cheese 16 from calf rennet had comparable sensory scores. Cheese 4 had significantly the lowest fat content among cheeses. Cheeses 6 and 14 had significantly higher percentages of lactic acid from cheeses 5 and 16. No significant differences were found in the mean percentage yield, moisture, total solids, protein, ash and salt. Examination of the 15 fungal milk-clotting isolates revealed that isolate number 1 appeared to be species of Geotrichum while eleven isolates numbering 2, 3, 4, 6, 7, 8, 10, 11, 12, 13 and 14, were identified under the Aspergillus niger group. Isolate 5 appeared to be a species of Humicola. Isolates 9 and 15 exhibited the same colony characteristics in all the three fungal media used but failed to sporulate and, therefore, remained unidentified
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