Fermentation technology improves the flavour and shelf life of foods while lowering antinutrient levels. Common bean, though a highly nutritious food, contains high levels of anti-nutrients. Fermentation can be exploited to lower antinutrients in common bean. Though significant strides have been made in bean milk and flour fermentation, common bean is majorly consumed as whole grain. This study, therefore, was aimed at developing a fermentation protocol for whole common bean. Lactobacillus plantarum BFE 5092 was used as starter culture for fermentation. Salt and salt-sugar at 1%, 2% and 3% solute concentrations were used as brine. The effect of starter culture, solute composition and concentration on the growth of lactic acid bacteria (LAB) was monitored. pH and microbial safety were also monitored during the fermentation process. Inoculation with Lb. plantarum BFE 5092 caused a significant increase (P<0.05) of LAB counts in salt brines compared to spontaneous fermentation but no significant difference (P>0.05) in salt-sugar brines. The pH of salt sugar brine solutions was significantly (P<0.05) lowered during the fermentation process from 6.07 to ≤ 3.75. This inhibited enterobacteria growth while promoting the growth of yeast. In salt brines, the pH was ≥ 4.8 favoring enterobacterial growth while inhibiting yeast growth. Solute concentration had no significant effect (P>0.05) on the growth of LAB, pH and microbial safety during fermentation. The study established that use of salt-sugar brine was effective in promoting the growth of LAB during common bean fermentation. It also lowered the pH to ≤ 3.75 and inhibited enterobacterial growth unlike salt brines.

Common beans are a leguminous plant of the genus Phaseolus. They are rich in protein, energy, and minerals. They confer a wide range of health benefits when consumed. Utilization of common bean has however been poor due to high antinutrient content that results in reduced nutrient digestibility and mineral bioavailability. Flatulence after consumption is also a huge deterrent to common bean consumption. Lactic acid fermentation is the most common form of food fermentation with the Lactobacilli spp dominating most spontaneous fermentations. The objective of this study was to determine the effect of lactic acid bacteria (LAB) on the antinutrient and flatulence causing oligosaccharide composition of red haricot bean. A factorial research design was used in the study. Red haricot beans were sorted and soaked for 15 h. The soaked beans were fermented in 2% salt-sugar solutions for 120 h. Experimental batch was inoculated with Lb. plantarum BFE 5092 (IF), and the control batch was spontaneously fermented (SF). Microbial growth and pH were monitored every 24 h during fermentation. After fermentation, the beans were dried and milled, and the flours were subjected to biochemical analysis. ANOVA was done using SPSS statistics 23. The pH decreased significantly (P<0.05) from 6.06 to 3.9 in both batches at the end of fermentation. The LAB counts significantly increased (P<0.05) in both batches, whereas coliform counts decreased significantly (P<0.05). Fungi were not detected in both batches. Soaking lowered tannins and phytates and raffinose concentrations significantly but had no significant effect on stachyose concentration. At the end of 120 h of fermentation, the tannin content was 109.50 and 54.04 mg/100 g in IF and SF, respectively. Phytates were at 242.52 and 163.43 mg/100 g in IF and SF, respectively. Raffinose content was 32.85 and 32.58 mg/100 g in IF and SF, respectively, while stachyose content was 593.33 and 467.49 mg/100 g in IF and SF, respectively. This research showed that LAB is able to ferment soaked whole red haricot and lower the tannin, phytate, raffinose, and stachyose content significantly. Spontaneous fermentation lowered these antinutrients and oligosaccharides better than inoculation with Lb. plantarum BFE 5092.

Common beans (Phaseolus vulgaris L.) are nutritious and confer numerous health benefits. However, they are also high raffinose family oligosaccharides (RFOs) and antinutrients. Appreciable amounts of RFOs and antinutrients remain after soaking and cooking, causing flatulence and lowered mineral bioavailability to bean consumers. Fermentation has been shown to lower RFOs and antinutrients in bean flours and milk. However, beans are majorly consumed as whole grains. The purpose of this study was to develop a protocol for fermenting whole common beans. We fermented boiled whole red haricot beans and evaluated their effect on RFOs, tannins, and phytates. A factorial research design was used. Beans were sorted, soaked for 15 h, and boiled for 1 h. The beans were then fermented in 2% salt-sugar solution (SSF) and 2% salt-only solution (SOF) for 120 h. Microbial growth and pH were monitored every 24 h during fermentation. After fermentation, the beans were dried, milled, and the flours subjected to biochemical analysis. Fermentation favored the growth of lactic acid bacteria (LAB), lowering the pH to 3.88 and 5.26 in SSF and SOF batches, respectively. Tannin content reduced significantly by 64.70% and 73.19% in the SSF and SOF batches, respectively. Phytates reduced by 58.88% and 68.85%, respectively. Raffinose reduced significantly by 96.40% and 95.01%, respectively, whereas stachyose reduced by 95.92% and 94.11%, respectively. The highest reduction of antinutrients and RFOs occurred between 24 and 72 h of fermentation. Higher antinutrient losses occurred in the SOF batch, whereas higher RFO losses occurred in the SSF batch.