Impact of Nutritionally Stressed Lactobacillus plantarum D1 on Composition of Fermented Cassava

Abstract

Aim: Bacteria in their natural habitat, including Lactobacillus sp., are subjected to various types of stress, including physicochemical and nutritional stress with nutritional stress as one of the most common stress types. Lactobacillus plantarum is a versatile species of Lactic  Acid Bacteria (LAB) that is commonly used as a starter culture in cassava fermentation. This comparative study was designed to analyze the product quality of cassava fermented with nutritionally-stressed Lactobacillus plantarum (NS-L) and nutritionally-unstressed L. plantarum (NU-L). Methodology: The organism was starved by varying the percentage composition of the glucose (0.2% - 0.6% w/v), peptone and yeast extract (0.1 - 0.5% and 0.05 - 0.25% w/v), magnesium sulphate (0.001% - 0.004% w/v), and Tween 80 (0.02% - 0.06% v/v). Results: Cassava fermented with NS-L had higher ash content (2.26 ± 0.01% to 2.58 ± 0.01%), crude fat (0.15% to 0.28%), crude protein (1.38 ± 0.01 to 1.76 ± 0.01%), and crude fiber (1.14 ± 0.01 to 1.38 ± 0.00%) compared to NU-L. Mineral content (including phosphorus and iron) increased considerably in NS-L samples. However, anti-nutritional components were reduced in NS-L samples compared to those fermented with unstressed starter culture, with cyanide and phytate levels as low as 0.002 and 0.155 g/100g, respectively. Conclusion: Nutritional stress on L. plantarum resulted in better but variable functional characteristics on fermented cassava, indicating physiological adaptation and acclimatization to stress conditions.