TITLE:
Inclusion of Yeast Cultures (Saccharomyces cerevisiae) to Dairy Cows’ Urea-Treated Rice Straw Diets Improves Mozzarella Cheese Processing and Yield
AUTHORS:
Stephen Odera, Olivier Basole Kashongwe, Patrick Muliro Simiyu, Bockline Omedo Bebe
KEYWORDS:
Urea, Yeast, Crop Residues, Milk Composition, Cheese Yield
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.11 No.12,
December
24,
2020
ABSTRACT: This research paper addresses the hypothesis that adding yeast cultures
(Saccharomyces cerevisiae) to urea-treated cereal crop residues could improve
milk composition to the level of milk produced on pastures for the manufacture
of Mozzarella cheese. In three equal groups, Nine Friesian cows were randomly
assigned to three treatment diets in a completely randomized design. The
treatments were pasture (P), urea treated rice straw (UTRS), and urea treated
rice straw with yeast inclusion (UTRS + Y). Urea inclusion was at 3.8% of the
dry matter to treat rice straw, while yeast culture inclusion was 10 g/cow/day.
The experimental period was 21 days, with 14 days of adaptation. Data analysis
used general linear model procedure of SAS, fitting diet as a fixed effect and
milk composition, syneresis, curd firmness and cheese yield as the response
variables. Milk produced on UTRS diet yielded (p ·m-3) and casein-to-fat ratio (0.51). Yeast inclusion in the diet (UTRS + Y)
significantly improved milk density (1022.68 Kg·m-3) with marginal reduction in milk fat content (4.53%). In cheese making,
milk produced on URTS diets had significantly lower renneting time (1.4 minutes
vs 3.47 minutes and 2.39 minutes), least viscous gel, lowest syneresis (755 mL
vs 860 mL and 836 mL from 1000 mL), and lowest cheese yield (9.0% vs 11% and
10.5%) compared to P and UTRS + Y diets. Milk produced from P and UTRS + Y did
not show any significant difference in cheese yield. The findings indicated
that urea treated rice straw with yeast cultures improves syneresis, gel
viscosity and Mozzarella cheese yield. Therefore, we recommend the inclusion of
yeast to urea treated cereal crop residues to produce milk destined for
Mozzarella cheese making.