Influence of Fermentation on Mineral Bioaccessibility of Underutilized Millets

Millets are highly acknowledged for their nutrient-dense and climate-resilient nature providing a substantial source of essential micronutrients like zinc, iron, magnesium and calcium etc to combat malnutrition. But, the presence of antinutritional factors such as phytates, polyphenols results in inhibiting the bioaccessibility of significant minerals. Processing techniques such as soaking, germination, roasting, fermentation have been documented to modify the food matrix and to minimize the antinutritional compounds while enhancing mineral availability. Jowar-sprouted, jowar-roasted, jowar-fermented, ragi-Fermented and toasted where analyzed using standard AOAC methods. The quantification of phytates and polyphenols contents were done calorimeterically, where mineral bioaccessibility was assessed through a standardized simulated gastrointestinal digestion protocol.Analyses revealed clear disparities in mineral composition and bioaccessibility across the processed sample. Minimal variations shown in moisture and ash contents(6.5-7.8%) (2.1-2.5% respectively) indicating the impact of processing left a minor effect on these parameters. Fermentation enhanced iron and zinc content with iron levels reaching (4.0-4.9%mg/100gm) sprouted jowar to fermented and toasted ragi and zinc rising to the range of (2.0-27%mg/100gm). Magnesium content was consistent (96-126mg/100gm) whereas calcium showed the drastic difference with fermented-toasted-ragi contains (345mg/100gm) which compared to (42-48mg/100mg). Phytate levels were significantly reduced to (270-300mg/100gm) directly enhancing mineral content. Iron and Zinc bioaccessibility was significantly higher in fermented jowar (46-47% Fe, 50-52% Zn) compared to sprouted (40-45% Fe, 44-48% Zn) and roasted jowar respectively. Following fermentation, a marked increase in Calcium (22-24% up to 26-38%) and Magnesium (28-34% up to 40-48%) respectively. A negative correlation between the phytate content and mineral bioaccessibility which strongly highlights the influence of fermentation is highly effective to enhance nutrient uptake in underutilized millets.