Kinetic study of immobilized lactose-coated Lactobacillus plantarum BS with commercial yoghurt starter cultures of Streptococcus thermophilus and Lactobacillus delbrueckii spp. bulgaris on yoghurt production

Date

2011

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Request Access

To request access of this material, please email the administrator at uscs-mainlib.uplb@up.edu.ph

Abstract

Yoghurt fermentation using commercial yoghurt starter culture (YF-L903) and with the addition of Lactobacillus plantarum BS was more advantageous especially when L. plantarum BS cells were immobilized by coating it with lactose powder compared to its free-cell state. The Viability of immobilized BS cells that were refrigerated for seven weeks was high. Based on the initial count of BS cells which was 2.6E+10 cfu/g and on the final count which was 3.45E+09 cfu/g, it was still enough for it to be considered as a good source of probiotic bacteria. Yoghurt with 10% and 12% milk concentrations containing immobilized lactose-coated BS cells had higher biomass concentration which were 4.5833E+10 cfu/mL and 1.0917E+10 cfu/mL, respectively , compared with that of yoghurt with 10% and 12% milk concentrations containing free-cells of BS with biomass concentrations of 6.50E+08 cfu/mL and 7.50E+09 cfu/mL, respectively. The pH of yoghurt samples decreased through time and dropped until pH-4 which was ideal for yoghurt fermentation. The titratable acidity of yoghurt samples increased with time which meant that there was an increase of lactic acid build-up through time. As for the total sugar, the highest total consumption was recorded to be 44.38434 mg.mL for yoghurt with 12% milk concentration containing immobilized BS. The Tessier model was the most suitable model that could describe the growth of the microorganisms with freeBS cells and with immobilized BS cells. The computed values for Mmax for free BS cells and immobilized BS cells were 1,666.67 hr⁻¹ and 303.03 hr⁻¹. Moreover, the regression coefficients, R², for free cells and immobilized BS cells were 0.9627 and 0.9611, respectively. It meant that there existed a direct relationship between the growth rates and the substrate concentration provided that the maximum growth rate Mmax, had not yet been achieved.

Language

English

LC Subject

Enzyme kinetics

Location

UPLB College of Engineering and Agro-Industrial Technology (CEAT)

Call Number

LG 993.5 2011 E62 C36

Document Type

Thesis

This document is currently not available here.

Share

COinS