Yogurt Making – How Does Carbohydrate Type Affect Yogurt Chemistry?

 

Joanna R. Vondrasek

Tested Studies in Laboratory Teaching, 2014, Volume 35

Abstract

This is an inquiry-based lab intended to be used in a majors- or non-majors introductory biology course. There are several published and commercial examples of laboratory activities for biology courses that involve making yogurt or culturing the bacteria isolated from yogurt; however, these labs are typically completely directed or demonstration labs that do not allow for hypothesis generation or experimentation by the students. The main goal of this lab is to allow students to generate hypotheses about what chemical changes will occur to various substrates (different types of milk) during the process of lactate fermentation with Lactobacillus and related microbes. Students are provided with a basic yogurt making protocol and use test strips to measure pH and glucose concentration. Students devise their own methods for measuring yogurt consistency. This is a two-session lab exercise that requires students (or lab staff) to remove yogurt from incubators after 18-24 hours. The materials are inexpensive, and this lab can be scaled to large enrollment laboratory courses.

Keywords:  fermentation, yogurt, Lactobacillus, lactate

University of Calgary (2013)