Prebiotic synthesis from rice using Aspergillus oryzae with solid state fermentation

Solid-State Fermentation of Sorghum by Aspergillus oryzae and Aspergillus niger: Effects on Tannin Content, Phenolic Profile, and Antioxidant Activity

Sorghum contains antioxidants such as tannins. However, these are considered antinutritional factors since they are responsible for the low digestibility of proteins and carbohydrates. Nevertheless, these can be extracted by solid-state fermentation (SSF). Therefore, this study aimed to evaluate the effects of SSF from Aspergillus oryzae and Aspergillus niger Aa210 on the tannin contents, phenolic profiles determined by HPLC-MS, and antioxidant activities (ABTS, DPPH, and FRAP) of two genotypes of sorghum. The results showed that with SSF by A. niger Aa210, a higher tannin content was obtained, with yields of 70-84% in hydrolyzable tannins (HT) and 33-49% in condensed tannins (CT), while with SSF by A. oryzae the content of HT decreased by 2-3% and that of CT decreased by 6-23%. The extracts fermented by A. niger at 72 and 84 h exhibited a higher antioxidant activity. In the extracts, 21 polyphenols were identified, such as procyanidins, (+)-catechin, (-)-epicatechin, scutellarein, arbutin, and eriodictyol, among others. Therefore, SSF by A. niger was an efficient process for the release of phenolic compounds that can be used as antioxidants in different food products. It is also possible to improve the bioavailability of nutrients in sorghum through SSF. However, more studies are required.

Fermentation With Pleurotus Ostreatus Enhances the Prebiotic Properties of Germinated Riceberry Rice

Rice is the staple food for more than half of the world's population. In recent years, awareness of the health benefits of colored rice varieties and germinated rice has gradually increased. Riceberry rice (R), a black-purple variety, was germinated and subsequently fermented with Pleurotus ostreatus mycelium (M) to improve nutrient quality and prebiotic properties. The γ-aminobutyric acid (GABA) and β-glucan contents were measured daily for a total of 4 days. The prebiotic activities of R, germinated Riceberry rice (GR), and germinated Riceberry rice with mycelium (GRM) were evaluated on the probiotic bacteria Pediococcus sp., Lactobacillus acidophilus, and Streptococcus lactis. Results were compared with the M treatment and with the commercial prebiotic agents: inulin and β-glucan. The treatments were also used to evaluate growth of the pathogen Escherichia coli. The GABA content peaked after 3 days of germination. The GR sample fermented with M for 3 days had the optimal concentration of both β-glucan and GABA. Evaluation of the prebiotic properties of rice samples and the commercial standards (inulin and β-glucan) showed that these were enhanced on the GR and GRM treatments. Results also showed the improvement of prebiotic properties on GR as the R sample did not show any prebiotic properties in all probiotic bacteria, whereas the GR sample showed moderate prebiotic activity score of 0.40, 0.88, and 0.56 on Pediococcus sp., L. acidophilus, and S. lactis, respectively. Furthermore, the prebiotic activity of GR was improved when fermented with M. For further applications, the GRM could be used on rice-based products, such as rice flour, rice crackers, or other rice products to enhance nutritional value and improve digestive system health, especially in the elderly.

The challenges in production technology, health-associated functions, physico-chemical properties and food applications of isomaltooligosaccharides

Isomaltooligosaccharides (IMOs) are recognized as functional food ingredients with prebiotic potential that deliver health benefits. IMOs have attained commercial interest as they are produced from low-cost agricultural products that are widely available and have prospective applications in the food industry. The review examines the various production processes and the main challenges involved in deriving diverse structures of IMO with maximized yield and increased functionality. The different characterization and purification techniques employed for structural elucidation, the physico-chemical importance, technological properties, food-based applications and biological effects (in vitro and in vivo interventions) have been discussed in detail. The key finding is the need for research involving biotechnological and enzymology aspects to simplify the production technologies that meet the industrial and consumer requirements. The knowledge from this article delivers a clear insight to scientists, food technologists and the general public for the improved utilization of IMOs to support the emerging market for functional foods and nutraceuticals.

Fermentation and the microbial community of Japanese koji and miso: A review

Miso is a well-known traditional Japanese fermented food, with a characteristic savory flavor and aroma, known predominately as the seasoning in miso soup. Miso production involves a two-stage fermentation, where first a mold, such as Aspergillus oryzae, is inoculated onto a substrate to make koji. A subsequent fermentation, this time by bacteria and yeast, occurs when the koji is added to a salt and soybean mash, with the miso left to ferment for up to 2 years. The microbial community of miso is considered essential to the development of the unique taste, texture, and nutritional profile of miso. Despite the importance of microorganisms in the production of miso, very little research has been undertaken to characterize and describe the microbial process. In this review, we provide an overview of the two-stage fermentation process, describe what is currently known about the microbial communities involved and consider any potential health benefits associated with the consumption of miso, along with food safety concerns. As the popularity of miso continues to expand globally and is produced under new environmental conditions, understanding the microbiological processes involved will assist to ensure that global production of miso is safe as well as delicious.

Physiochemical, kinetic and thermodynamic studies on Aspergillus wewitschiae MN056175 inulinase with extraction of prebiotic and antioxidant Cynara scolymus leaves fructo-oligosaccharides

Utilization of agricultural wastes as cheap natural resources for production of bioactive products is currently attracting global attention. For this purpose, this study focused on isolation of Aspergillus wewitschiae MN056175 as promising producer of inulinase, then investigating physiochemical, kinetics and thermodynamics of the obtained inulinase, and its ability to extract bioactive fructo-oligosaccharides (FOS) from Cynara scolymus leaves (artichoke leaves, AL). A. wewitschiae MN056175 inulinase gave the maximum activity at temperature 60 °C and inulin concentration 1%. The kinetics including K_m and V_max were determined to be 105.26 mg·ml^-1 and 83.33 μmol·ml^-1·min^-1, respectively. The thermodynamics including, E_a (activation energy) and E_d (activation energy for denaturation) were determined to be 21.82 and 73.21 kJ·mol^-1, K_d, T_1/2, D-value, ΔH°, ΔG° and ΔS° at 40, 50 and 60 °C which indicated the stability of A. wewitschiae MN056175 inulinase. Moreover, this inulinase was capable of hydrolyzing Cynara scolymus leaves into reducing sugar and 15 FOS with different DP, total carbohydrate, and protein content under different conditions designed by central composite design (CCD). The 15 AL FOS showed different high antioxidant and prebiotic activities. Central FOS with probiotic bacteria exhibited significant antimicrobial activity against tested gram positive bacteria in a way higher than those recorded against gram negative bacteria.