Fermented food products, especially those derived from cereals and legumes are important contributors to diet diversity globally. These food items are vital to food security and significantly contribute to nutrition. Fermentation is a process that desirably modifies food constituents by increasing the palatability, organoleptic properties, bioavailability and alters nutritional constituents. This review focuses on deciphering possible mechanisms involved in the modification of nutritional constituents as well as nutrient bioavailability during the fermentation of cereals and legumes, especially those commonly consumed in developing countries. Although modifications in these constituents are dependent on inherent and available nutrients in the starting raw material, it was generally observed that fermentation increased these nutritive qualities (protein, amino acids, vitamins, fats, fatty acids, etc.) in cereals and legumes, while in a few instances, a reduction in these constituents was noted. A general reduction trend in antinutritional factors was also observed with a corresponding increase in the nutrient bioavailability and bioaccessibility. Notable mechanisms of modification include transamination or the synthesis of new compounds during the fermentation process, use of nutrients as energy sources, as well as the metabolic activity of microorganisms leading to a degradation or increase in the level of some constituents. A number of fermented products are yet to be studied and fully understood. Further research into these food products using both conventional and modern techniques are still required to provide insights into these important food groups, as well as for an overall improved food quality, enhanced nutrition and health, as well as other associated socioeconomic benefits.

Physico-chemical, sensory and microbiological characteristics of plain yoghurt from bambara groundnut and soybean milks were studied. Milks were prepared from bambara and soybean and then fermented using Lactobacillus delbruieckii subspp. bulgaricus and Streptococcus salivarus subspp. thermophilus to produce yoghurt. The yoghurts were stored at 7°C and 27°C for 9 days and their quality monitored. Results showed that pH of soy and bambara yoghurts decreased during the storage period for both storage temperatures. This decrease in pH was accompanied by simultaneous increase in titratable acidity. Total solids and apparent viscosities of soy and bambara yoghurts increased at 7°C, but decreased at 27°C during storage period. Bambara yoghurt received higher sensory acceptability than soy yoghurt. Predominant microorganisms in the stored yoghurts were lactic acid bacteria (LAB). The LAB count in the yoghurts stored at 7°C decreased but increased at 27°C during the storage period. Similar trends were followed by total aerobic bacteria, yeast and moulds counts. Pathogenic bacteria such as Salmonella, Coliform and E. coli were absent in all the yogurt samples. Yoghurts of acceptable quality and safety were produced from bambara groundnut and soybeans.

The overarching challenges of mycotoxin contamination in food necessitate the development of strategies to be implemented to combat their effects thereof. Common processing techniques have been utilised but do not necessarily meet the desired efficacy. This review appraises studies on novel non-thermal food processing techniques, particularly high pressure processing, pulsed electric filed, cold plasma and ultrasound processing for the decontamination of mycotoxins in food. Although available studies on these techniques have suggested a reduction of mycotoxins and in some instances, complete decontamination of mycotoxins was also reported. The mechanisms by which reduction/elimination occurs include through decomposition of toxins after collision with ions/electrons leading to cleavage of bonds, structural degradation of the mycotoxins structure and cleavage of functional groups. Additional studies into the toxicity of degraded products and the composition of the food products are still required to ensure a more widespread adoption of these techniques to enhance food safety.

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