Stabilization and preservation of probiotic properties of the traditional starter of African opaque sorghum beers

This present study assessed the impact of drying process parameters, that is temperature and drying duration, on the dry matter content, pH, titratable acidity, yeasts and lactic acid bacteria content of granule starter of African opaque sorghum beer. Probiotic properties of the dry starter were tested. The aim was to establish levels of temperature and duration of drying that lead to a longer shelf life and optimum activity of the starter. Results show that the drying temperature has significant effects on the titratable acidity, yeasts and lactic acid bacteria contents of the granule starter while the level of dry matter was significantly affected by both temperature and duration of drying. The optimal drying conditions providing a stable granule starter with optimum viability of lactic acid bacteria and yeasts were established to 43°C and 24 h. Both wet and dried starters showed inhibitory effect on the meticillin resistant Staphylococcus aureus.Keywords: sorghum, opaque beer, starter, yeats, probiotic, Response Surface Methodolog

Extraction methods and food uses of a natural red colorant from dye sorghum

BACKGROUND: The interest in stable natural colorants for food applications continues to grow. A red pigment extracted from the leaf sheaths of a sorghum variety (Sorghum bicolor) with a high content of apigeninidin is widely used as a biocolorant in processed foods in West Africa. This study compared the colour and anthocyanin composition from traditional extraction methods to determine options for improvement and use of the red biocolorant from dye sorghum in the food sector. RESULTS: Sorghum biocolorant was commonly applied in fermented and heated foods. Traditional extraction methods predominantly differed in two aspects, namely the use of an alkaline rock salt (locally known as kanwu) and the temperature of the extraction water. Cool extraction using the alkaline ingredient was more efficient than hot alkaline and hot aqueous extractions in extracting anthocyanins. The apigeninidin content was three times higher in the cool and hot alkaline extracts than in the aqueous extract. CONCLUSION: Cool and hot alkaline extractions at pH8-9 were the most efficient methods for extracting apigeninidin from dye sorghum leaf sheaths. Broader use of the sorghum biocolorant in foods requires further research on its effects on nutrient bioavailability and antioxidant activity

Effects of Genotype and Growth Temperature on the Contents of Tannin, Phytate and in vitro Iron Availability of Sorghum Grains

Background: It has been predicted that the global temperature will rise in the future, which means crops including sorghum will likely be grown under higher temperatures, and consequently may affect the nutritional properties. Methods: The effects of two growth temperatures (OT, day/night 32/21°C; HT 38/21°C) on tannin, phytate, mineral, and in vitro iron availability of raw and cooked grains (as porridge) of six sorghum genotypes were investigated. Results: Tannin content significantly decreased across all sorghum genotypes under high growth temperature (P ≤0.05), while the phytate and mineral contents maintained the same level, increased or decreased significantly, depending on the genotype. The in vitro iron availability in most sorghum genotypes was also significantly reduced under high temperature, except for Ai4, which showed a pronounced increase (P ≤0.05). The cooking process significantly reduced tannin content in all sorghum genotypes (P ≤0.05), while the phytate content and in vitro iron availability were not significantly affected. Conclusions: This research provides some new information on sorghum grain nutritional properties when grown under predicted future higher temperatures, which could be important for humans where sorghum grains are consumed as staple food

Extraction methods and food uses of a natural red colorant from dye sorghum

BACKGROUND: The interest in stable natural colorants for food applications continues to grow. A red pigment extracted from the leaf sheaths of a sorghum variety (Sorghum bicolor) with a high content of apigeninidin is widely used as a biocolorant in processed foods in West Africa. This study compared the colour and anthocyanin composition from traditional extraction methods to determine options for improvement and use of the red biocolorant from dye sorghum in the food sector. RESULTS: Sorghum biocolorant was commonly applied in fermented and heated foods. Traditional extraction methods predominantly differed in two aspects, namely the use of an alkaline rock salt (locally known as kanwu) and the temperature of the extraction water. Cool extraction using the alkaline ingredient was more efficient than hot alkaline and hot aqueous extractions in extracting anthocyanins. The apigeninidin content was three times higher in the cool and hot alkaline extracts than in the aqueous extract. CONCLUSION: Cool and hot alkaline extractions at pH8-9 were the most efficient methods for extracting apigeninidin from dye sorghum leaf sheaths. Broader use of the sorghum biocolorant in foods requires further research on its effects on nutrient bioavailability and antioxidant activity