Development of probiotic mutandabota, a locally sustainable functional food incorporating Lactobacillus rhamnosus

A. Mpofu

Research output: Thesisinternal PhD, WU

Abstract

Development of probiotic mutandabota, a locally sustainable functional food incorporating Lactobacillus rhamnosus

Mutandabota or umlondo is an indigenous food that is consumed in Southern Africa on a daily basis. The product is made by mixing raw cow’s or goat’s milk with 14 % (wt/vol) dry pulp of the baobab fruit (Adansonia digitata L.) and 7 % sugar. Mutandabota has a high protein content, and is rich in vitamin C and minerals. It also provides fibre to the diet, which evidently has potential health benefits in preventing diabetes, cardiovascular diseases, some cancers and constipation. Predominant microorganisms were isolated from mutandabota and identified. This indicated that different species of bacteria and yeast survive the acidity and low pH of 3.4±0.1 in mutandabota. While no pathogens were isolated, the identified microorganisms are capable of spoiling the product. Preparation of mutandabota is a gendered activity dominated by women.

A probiotic dairy product was then developed at village level on the basis of mutandabota to enable resource-poor populations in Southern Africa to accrue health benefits from a functional food. Raw cow’s milk was pasteurised and dry baobab fruit pulp was added to the milk at a concentration of 4 % (wt/vol). This mixture was inoculated with the probiotic Lactobacillus rhamnosus yoba, an isolate of Lactobacillus rhamnosus GG, and left to ferment for 24 h. Baobab fruit pulp at 4% promoted growth of L. rhamnosus yoba. More pulp and sugar were then added to produce yoba mutandabota with 14 % (wt/vol) baobab fruit pulp and 7 % sugar. The final pH of yoba mutandabota was pH 3.5, which ensured the microbiological safety of the product. Viable plate count of L. rhamnosus yoba was 8.8 ± 0.4 log cfu/mL at the moment of consumption, thereby meeting the criterion to have a viable count of the probiotic bacterium in excess of 6 log cfu/mL in the product.

There was no significant difference (p=0.31) in consumers’ preference between traditional and yoba mutandabota, despite a significant difference (p<0.001) in sensorial properties of the two products. Challenge tests to evaluate the impact of L. rhamnosus yoba on competing pathogens in mutandabota were done. In traditional mutandabota (pH 3.4±0.1) some food-borne pathogens survived and withstood the acids and low pH of the product. However, yoba mutandabota (pH 3.4±0.1) inactivated all tested food-borne bacterial pathogens during the 24 h potential consumption time. This demonstrated that yoba mutandabota can be safer stored than traditional mutandabota. The L. rhamnosus yoba showed robustness and grew from 5.5 log cfu/mL to 9.0 log cfu/mL within 24 h in the presence of pathogens in yoba mutandabota.

The outcome of this work was a safe, healthy, optimum-quality product of relevant nutritional value. Although this work focused on growth of L. rhamnosus yoba in mutandabota, the potential exists to apply this approach to other traditional foods worldwide as a low-cost method to improve dietary quality and gastro-intestinal health of consumers. Yoba mutandabota processing and trading may ameliorate the well-being of rural households through improvements in health status and livelihoods.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Zwietering, Marcel, Promotor
  • Smid, Eddy, Promotor
  • Linnemann, Anita, Co-promotor
Award date19 Oct 2015
Place of PublicationWageningen
Publisher
Print ISBNs9789462574731
Publication statusPublished - 2015

Keywords

  • adansonia digitata
  • adansonia
  • raw milk
  • goat milk
  • lactobacillus rhamnosus
  • probiotics
  • food safety
  • qualitative analysis
  • quantitative analysis

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