Modulating conversion of isoflavone glycosides to aglycones using crude beta-glycosidase extracts from almonds and processed soy

Incorporating whole soybean pulp into wheat flour for nutrient-enriched steamed bread: Exploring the impact on physical and nutritional characteristics

This research explored the impact of incorporating various levels of whole soybean pulp (WSP) (10%, 20%, 30%, 40%, and 50%) into wheat flour on the physical and nutritional qualities of steamed bread. In comparison with the traditional steamed bread, the substitution of up to 20% WSP did not significantly alter the specific volume, hardness, and chewiness of the steamed bread. Additionally, the crumb texture of the steamed bread with 20% WSP maintained small and uniform pores, with optimal springiness and cohesiveness. Nutritionally, the substitution of 10%-50% WSP enhanced total dietary fiber, total phenolics, and protein by 9.40%-89.79%, 14.96%-116.31%, and 3.45%-34.36%, respectively. Isoflavones in the steamed bread increased markedly from 22.92 µg/g to a range of 140.12-997.12 µg/g. The expected glycemic index showed a decrease from 90.24 to between 85.85 and 70.75, whereas amino acid scores improved from 59.22 to a range of 64.58-65.08, with lysine (Lys) scores notably increasing from 59.22 to between 64.96 and 88.80. In conclusion, partially replacing wheat flour with WSP is an effective method for enhancing the nutritional profile and addressing the essential amino acid imbalance in steamed bread. PRACTICAL APPLICATION: This study partially replaced flour with WSP to improve the steamed bread's nutritional quality. The optimal substitution level was determined to be 20% WSP, which improves the bread's nutritional value without significantly impacting its physical qualities. Furthermore, WSP is produced from soaked soybeans through hot water milling. This process simplifies soybean processing, lowers energy consumption and costs, and reduces pollution. It also effectively retains essential nutrients, such as protein, dietary fiber, polyphenols, and soy isoflavones, ensuring the full utilization of soybeans.

Natural Amino Acid-Bearing Carbamate Prodrugs of Daidzein Increase Water Solubility and Improve Phase II Metabolic Stability for Enhanced Oral Bioavailability

Daidzein (DAN) is an isoflavone, and it is often found in its natural form in soybean and food supplements. DAN has poor bioavailability owing to its extremely low water solubility and first-pass metabolism. Herein, we hypothesized that a bioactivatable natural amino acid-bearing carbamate prodrug strategy could increase the water solubility and metabolic stability of DAN. To test our hypothesis, nine amino acid prodrugs of DAN were designed and synthesized. Compared with DAN, the optimal prodrug (daidzein-4'-O-CO-N-isoleucine, D-4'-I) demonstrated enhanced water solubility and improved phase II metabolic stability and activation to DAN in plasma. In addition, unlike the passive transport of DAN, D-4'-I maintained high permeability via organic anion-transporting polypeptide 2B1 (OATP2B1)-mediated transport. Importantly, D-4'-I increased the oral bioavailability by 15.5-fold, reduced the gender difference, and extended the linear absorption capacity in the pharmacokinetics of DAN in rats. Furthermore, D-4'-I exhibited dose-dependent protection against liver injury. Thus, the natural amino acid-bearing carbamate prodrug strategy shows potential in increasing water solubility and improving phase II metabolic stability to enhance the oral bioavailability of DAN.

Improvement of Aglycone Content in Soy Isoflavones Extract by Free and Immobilized Β-Glucosidase and their Effects in Lipid Accumulation

Soybean is one of the most important commodities in the world, being applied in feed crops and food, pharmaceutical industries in different ways. Soy is rich in isoflavones that in aglycone forms have exhibited significant anti-obesity and anti-lipogenic effects. Obesity is a global problem as several diseases have been related to this worldwide epidemic. The aim of this work was to verify the effect of free and immobilized β-glucosidase, testing Lentikats, and sol-gel as carriers. Moreover, we wanted to examine if the different types of hydrolysis would generate extracts with distinct biological activity concerning lipid accumulation, PPAR-α regulation, and TNF-α, IL-6, and IL-10 concentrations using in vitro assays. Our results show that all formulations of β-glucosidase could hydrolyze soy isoflavones. Thus, after 24 h of incubation, daidzein content increased 2.6-, 10.8-, and 12.2-fold; and genistein content increased 11.7, 11.4, and 11.4 times with the use of free enzyme, Lentikats®, and sol-gel immobilized enzyme, respectively. Moreover, both methodologies for enzyme immobilization led to promising forms of biocatalysts for application in the production of soy extracts rich in isoflavones aglycones, which are expected to bring about health benefits. A mild lipogenic effect was observed for some concentrations of extracts, as well as a slight inhibition in PPAR-α expression, although no significant differences were noticeable in the cytokines TNF-α, IL-10, and IL-6 as compared with the control.

Isolation of Penicillium citrinum from Roots of Clerodendron cyrtophyllum and Application in Biosynthesis of Aglycone Isoflavones from Soybean Waste Fermentation

Soybeans offer an abundant source of isoflavones, which confer useful bioactivities when existing in aglycone forms. The conversion of isoflavones into aglycones via fermentation of soybean products is often realized by β-glucosidase, an enzyme produced by fungi. In this study, a filamentous fungus, Clerodendron cyrtophyllum, was isolated from root of Clerodendron cyrtophyllum Turcz, which was able to produce the highest activity of β-glucosidase up to 33.72 U/mL at 144 h during fermentation on Potato Dextrose Broth (PDB). The obtained fungus was grown on isoflavones-rich soybean extract to produce genistein and daidzein, achieving the conversion rate of 98.7%. Genistein and daidzein were isolated and purified by column chromatography using hexane/acetone (29:1/1:1), reaching purities of over 90% of total isoflavones, as identified and determined by TLC, LC-MS/MS, and 1H and 13C NMR spectroscopy. These results imply that the isolated P. citrinum is a potential fungal strain for industrial-scale production of genistein and daidzein from isoflavones-containing soybean extracts. These products may serve as potential raw materials for manufacture of functional foods that are based on aglycones.

Enhanced biotransformation of soybean isoflavone from glycosides to aglycones using solid-state fermentation of soybean with effective microorganisms (EM) strains

To improve the biotransformation efficacy (BE) of glycosides to aglycones in total soybean isoflavone (SIF), Taguchi experimental design has been used to study the most significant factors on BE of glycosides to aglycones using solid-state fermentation (SSF) of soybean with effective microorganisms (EM) strains. Physicochemical properties of optimized fermented dregs have also been analyzed to evaluate their probiotics count and mainly nutritional parameters. The results showed that identified optimal fermentation conditions are 30°C, 40% water content, 5% inoculation level, 6 d culture time, and 20 mesh number. BE of aglycones reached 85.30% with dry matter recoveries of 96.34% based on optimal fermentation conditions. Total bacterial and lactic acid bacteria count reached 17.98 and 9.34 × 108 CFU/g with decreasing pH (4.21) and an increasing acidity (8.62 g/kg), respectively. This study could provide the theoretical grounds for aglycones biotransformation in large-scale production applied in food and other fields. PRACTICAL APPLICATIONS: Isoflavones widely present in soy products possessing strong antioxidant capacity and estrogen-like activity. In human intestines, aglycone isoflavones after treatment/fermented are absorbed faster than their glucosides in untreated soybeans. The majority of glucoside isoflavones in soybean during fermentation were biologically converted to bioactive aglycone isoflavones via EM strains-fermented β-glucosidase. SSF of soybean with EM cocultures to ferment soymilk efficiently increased BE of glycosides to aglycones. Hence, EM cocultures as a new functional ingredient could improve the nutritional value of fermented soybean.

Isoflavones and bone health in perimenopausal and postmenopausal women

PURPOSE OF REVIEW

Isoflavones exert estrogenic activity distinct from estrogen, they have the potential to treat diseases and symptoms related to estrogen deficiency with minimal side effects and risks. Isoflavone supplementation, in general, is shown to exert beneficial effects against estrogen-deficient bone loss in women, however, some clinical trials still produce conflicting findings. The purpose of this review is to highlight and summarize the most recent and up-to-date research in the field and to bring attention to factors that play a major role in the outcomes of clinical trials that investigate phytoestrogens. Here, we also discuss the latest and most relevant data regarding the clinical safety of these substances.

RECENT FINDINGS

Isoflavones are naturally occurring secondary metabolites found in the Fabacaea plant family. Clinical data from isoflavone interventions support that aglycones (abundant in fermented products) exert enhanced beneficial effects against estrogen-deficient bone loss in women compared with isoflavone glycosides. Studies that employ methods to determine isoflavone content and form of treatments are more likely detect beneficial effects on bone. EFSA have confirmed the safety of isoflavones for women in the most comprehensive report to date.

SUMMARY

Isoflavone aglycones exert greater effects against bone loss than glycosides. Isoflavones show promise as a first-line prophylactic/treatment for bone loss in women.