Aims To determine the starter culture and multifunctional potentials of yeast strains from some cereal‐based Nigerian traditional fermented food products. Methods and Results Yeast isolates were screened for enzyme production and identified by sequencing the D1/D2 region of 26S rDNA. Pichia kluyveri LKC17, Issatchenkia orientalis OSL11, Pichia kudriavzevii OG32, Pichia kudriavzevii ROM11 and Candida tropicalis BOM21 exhibited the highest protease, lipase and phytase activity. They were selected and further evaluated for gastrointestinal survival and adherence ability. Although strain‐specific, they retained viability at 37°C and showed survival at pH 2·0., I. orientalis OSL11 showed the highest survival at 2% bile salts concentration and P. kudriavzevii ROM11 showed the least survival. The yeast strains showed strong autoaggregation ability (81·24–91·85%) and hydrophobicity to n‐hexadecane (33·61–42·30%). The highest co‐aggregation ability was detected for P. kudriavzevii OG32 and Escherichia coli (71·57%). All the yeast strains removed cholesterol in the range of 49·03–74·05% over 48 h and scavenged for free radicals in methanol reaction system. Conclusions In this study, we isolated new yeast strains with multifunctional potentials that can be used as functional starter cultures to produce cereal‐based probiotic products. Significance and Impact of the Study The development of probiotic yeast strains as starter culture to improve the quality attributes and confer functional value on cereal‐based traditional fermented foods is beneficial.
1 February 2017 in Current Opinion in Food Science
Probiotic strains contribute to the functionality of foods during fermentation. In this present work, cereal‐mix was fermented with probiotic Pichia kudriavzevii OG32. Selected fermentation parameters and functional properties of the product were determined. The growth of Pichia kudriavzevii OG32 was supported by the cereal‐mix containing 1% salt and 0.2% red chili powder to counts of between 7.46 and 8.22 Log10 cfu/mL within 24 h. Pichia kudriavzevii OG32 increased the viscosity of cereal‐mix with the highest inoculum size (1.84x105cfu/ml) giving the highest viscosity of 1793.6 mPa.S. An inoculum size of 1.98 × 104 cfu/mL gave the most acceptable product based on the sensory evaluation by the panelist. Forty volatile compounds were identified in the fermented product, while acids (32.21%) and esters (32.37%) accounted for the largest proportions. The cereal‐based fermented product scavenged DPPH from 200 μmol/L methanolic solution by 55.71%. Probiotic yeast improved the sensory and some functional properties of cereal‐based substrate during fermentation. This is one of the first reports on the volatile composition of cereal‐based functional food produced with probiotic yeast.
Animal milk types in sub‐Saharan Africa (SSA) are processed into varieties of products using different traditional methods and are widely consumed by households to support nutritional intake and diet. Dairy products contain several microorganisms, their metabolites, and other chemical compounds, some with health benefits and many others considered as potential health hazards. Consumption of contaminated milk products could have serious health implications for consumers. To access the safety of milk products across SSA, studies in the region investigating the occurrences of pathogens as well as chemical compounds such as heat stable toxins and veterinary drug residues in animal milk and its products were reviewed. This is done with a holistic view in light of the emerging exposome paradigm for improving food safety and consumer health in the region. Herein, we showed that several published studies in SSA applied conventional and/or less sensitive methods in detecting microbial species and chemical contaminants. This has serious implications in food safety because the correct identity of a microbial species and accurate screening for chemical contaminants is crucial for predicting the potential human health effects that undermine the benefits from consumption of these foods. Furthermore, we highlighted gaps in determining the extent of viral and parasitic contamination of milk products across SSA as well as investigating multiple classes of chemical contaminants. Consequently, robust studies should be conducted in this regard. Also, efforts such as development cooperation projects should be initiated by all stakeholders including scientists, regulatory agencies, and policy makers to improve the dairy product chain in SSA in view of safeguarding consumer health.
15 December 2022 in Probiotics and Antimicrobial Proteins