Production and Quality Characteristics of Yoghurt From Malted and Unmalted Soybeans.

ABSTRACT.

Yoghurt was prepared from soymilk equivalent made from malted and unmalted soybeans. Soybeans were processed and mixed with water in ratio of 1:5. One kilogram (1kg) of soybean produced soymilk equivalent of 5 litres (5L). The soymilk samples were exposed to ambient temperature (27°C). Titrable acidity, pH, specific gravity and total solids were monitored on hourly basis for 8 hours. Titrable acidity increased with an increase in storage period while pH tended towards acidity. The soymilk from unmalted soybean separated at about 5th hour from milk production while soymilk from malted soybean curdled at about 7th hour from the time of milk production. The same parameters were also monitored on daily basis for 4 days. The malted soya rnilk had lower microbial load than the unmalted sample. The Soya milk equivalent obtained was fermented to yoghurt at 37°C for 12-16 hours using Lactobacillus bulgaricus and Streptococcus tlierrnopliilus as starter culture in ratio of 1:1. The yoghurt produced was compared with conventional yogurt using sensory evaluation. Yogurt from malted and unmalted soybean compared favourably with reference yoghurt (from cow milk) in terms of colour, flavour and consistency. Yoghurt from cow milk was more sour (P ~ 0.05) than Soya milk yoghurt.

 TABLE OF CONTENT.

Certification. ii

Dedication. 'iii

Acknowledgement. iv

Table of Contents. v

List of Tables. vii

List of Figures viii

Abstract. ix

1.1.0 Introduction. I

1.2.0 Justification. 3

1.3.0 Statement of the Problem. 3

1.4.0 Objectives. .' 4

2.0.0 Literature Review. 5

2.1.0 Soybean. 5

2.1.1 O.rigin and distribution of Soybean. 5

2.1.2 Chemistry and Nutritional value of Soybean. 6

2.1.3 The role of Soybean in the Diet. 6

2.1.4 Anti-Nutritional Factors in Soybean. 8

2.2.0 Soyrnilk. 9

2.2.1 Origin of Soymilk, 9

2.2.2 Classification of Soymilk. 10

2.2.3 Nutritional value of Soymilk. 10

2.2.4 Processing of Soymilk. 12

2.2.5 Effect of Germination on the Chemical Composition of

soyrnilk. 13

2.2.6 Shelf Life of Soymilk. 14

2.3.0 Soy Yoghurt. 14

2.3.1 Nutritional Quality of Yoghurt. 15

2.3.2 Health Benefits of Yoghurt culture. 16

3.0.0 Materials and Methods. 17

3.1.0 Raw Materials. 17

3.2.0 Proximate Analysis of Soymilk. 17

3.2.1 Determination of Moisture Content. 17

3.2.2 Determination of fat Content. 17

3.2.3 Determination of crude protein Content. 17

3.2.4 Determination of Carbohydrate Content. 17

3.3.0 Shelf Life Studies. 19

3.3.1 Determination of Curdling time. 20

3.3.2 Determination of Microbial load. 22

3.3.3 Identification of Micro-organisms in Unmalted and Malted

Soymilk. 23

3.4.0 Production of Yoghurt from Unmalted and Malted

Soymilk. 23

3.5.0 Sensory Evaluation. 24

4.0.0 Results and Discussion. 25

4.2.0 Effect of Exposure time on curdling of Soymilk

samples. 26

5.0.0 Conclusion/Recommendation. 36

4 References. 37

Appendix.