Impact of food matrix on isoflavone metabolism and cardiovascular biomarkers in adults with hypercholesterolemia

Short-Term Soy Bread Intervention Leads to a Dose-Response Increase in Urinary Isoflavone Metabolites and Satiety in Chronic Pancreatitis

Patients with chronic pancreatitis (CP) are particularly vulnerable to nutrient malabsorption and undernutrition caused by the underlying pathology of their disease. Dietary intervention trials involving soy isoflavones in patients with CP are limited and isoflavone metabolites have not yet been reported. We hypothesized soy bread containing plant-based protein, dietary fiber, and isoflavones would be well-tolerated and restore gut functional capacity which would lead to isoflavone metabolites profiles like those of healthy populations. Participants (n = 9) received 1 week of soy bread in a dose-escalation design (1 to 3 slices/day) or a 4-week maximally tolerated dose (n = 1). Dietary adherence, satiety, and palatability were measured. Isoflavone metabolites from 24 h urine collections were quantified using high-performance liquid chromatography. A maximum dose of three slices (99 mg of isoflavones) of soy bread per day was achieved. Short-term exposure to soy bread showed a significant dose-response increase (p = 0.007) of total isoflavones and their metabolites in urine. With increasing slices of soy bread, dietary animal protein intake (p = 0.009) and perceived thirst (p < 0.001) significantly decreased with prolonged satiety (p < 0.001). In this study, adherence to short-term intervention with soy bread in CP patients was excellent. Soy isoflavones were reliably delivered. These findings provide the foundation for evaluating a well-characterized soy bread in supporting healthy nutrition and gut function in CP.

Catechin Bioavailability Following Consumption of a Green Tea Extract Confection Is Reduced in Obese Persons without Affecting Gut Microbial-Derived Valerolactones

Obesity-related cardiometabolic disorders are driven by inflammation, oxidative stress, and gut dysbiosis. Green tea catechins protect against cardiometabolic disorders by anti-inflammatory, antioxidant, and prebiotic activities. However, whether obesity alters catechin bioavailability remains unknown. We hypothesized that obesity would decrease catechin bioavailability due to altered gut microbiota composition. Obese and healthy persons completed a pharmacokinetics trial in which a confection formulated with green tea extract (GTE; 58% epigallocatechin gallate, 17% epigallocatechin, 8% epicatechin, 6% epicatechin gallate) was ingested before collecting plasma and urine at timed intervals for up to 24 h. Stool samples were collected prior to confection ingestion. Catechins and γ-valerolactones were assessed by LC-MS. Obesity reduced plasma area under the curve (AUC_0-12h) by 24-27% and maximum plasma concentrations by 18-36% for all catechins. Plasma AUC_0-12h for 5'-(3',4'-dihydroxyphenyl)-γ-valerolactone and 5'-(3',4',5'-trihydroxyphenyl)-γ-valerolactone, as well as total urinary elimination of all catechins and valerolactones, were unaffected. ⍺-Diversity in obese persons was lower, while Slackia was the only catechin-metabolizing bacteria that was altered by obesity. Ascorbic acid and diversity metrics were correlated with catechin/valerolactone bioavailability. These findings indicate that obesity reduces catechin bioavailability without affecting valerolactone generation, urinary catechin elimination, or substantially altered gut microbiota populations, suggesting a gut-level mechanism that limits catechin absorption.

The Antioxidant Role of Soy and Soy Foods in Human Health

Oxidative stress seems to play a role in many chronic diseases, such as cardiovascular diseases, diabetes, and some cancers. Research is always looking for effective approaches in the prevention and treatment of these pathologies with safe strategies. Given the central role of nutrition, the identification of beneficial healthy foods can be the best key to having a safe and at the same time effective approach. Soy has always aroused great scientific interest but often this attention is galvanized by the interaction with estrogen receptors and related consequences on health. However, soy, soy foods, and soy bioactive substances seem to have antioxidant properties, suggesting their role in quenching reactive oxygen species, although it was frequently mentioned but not studied in depth. The purpose of this review is to summarize the scientific evidence of the antioxidant properties of soy by identifying the human clinical trials available in the literature. A total of 58 manuscripts were individuated through the literature search for the final synthesis. Soy bioactive substances involved in redox processes appear to be multiple and their use seems promising. Other larger clinical trials with adequate standardization and adequate choice of biomarkers will fill the gap currently existing on the suggestive role of soy in antioxidant mechanisms.

Reduction of inflammation in chronic pancreatitis using a soy bread intervention: A feasibility study

INTRODUCTION

Chronic pancreatitis is a chronic inflammatory disease, which progresses to fibrosis. Currently there are no interventions to delay or stop the progression to irreversible organ damage. In this study, we assessed the tolerability and feasibility of administering soy bread to reduce circulating inflammatory mediators.

METHODS

Subjects with chronic pancreatitis diagnosed using the American Pancreatic Association diagnostic guidelines were enrolled. During the dose escalation (DE) phase, subjects received one week of soy bread based using a 3 + 3 dose-escalation design, which was then followed by a maximally tolerated dose (MTD) phase with four weeks of intervention. Dose-limiting toxicities (DLTs) were monitored. Plasma cytokine levels were measured using a Meso Scale Discovery multiplex assay kit. Isoflavonoid excretion in 24-h urine collection was used to measure soy bread compliance.

RESULTS

Nine subjects completed the DE phase, and one subject completed the MTD phase without any DLTs at a maximum dosage of three slices (99 mg of isoflavones) per day. Reported compliance to soy bread intervention was 98%, and this was confirmed with urinary isoflavones and their metabolites detected in all subjects. There was a significant decline in the TNF-α level during the DE phase (2.667 vs 2.382 pg/mL, p = 0.039); other levels were similar.

CONCLUSIONS

In this feasibility study, there was excellent compliance with a short-term intervention using soy bread in chronic pancreatitis. Reduction was seen in at least one pro-inflammatory cytokine with short-term intervention. Larger cohorts and longer interventions with soy are warranted to assess the efficacy of reducing pro-inflammatory mediators of disease.

Legume Consumption and Cardiometabolic Health

Legumes are key components of several plant-based diets and are recognized as having a wide range of potential health benefits. Previous systematic reviews and meta-analyses have summarized the evidence regarding different cardiometabolic outcomes, such as cardiovascular disease (CVD) and type 2 diabetes (T2D), and legume consumption. However, those studies did not differentiate between nonsoy and soy legumes, which have different nutritional profiles. The aim of the present updated review, therefore, was to summarize and meta-analyze the published evidence regarding legume consumption (making a distinction between nonsoy and soy legumes) and cardiometabolic diseases. In addition, we reviewed randomized clinical trials assessing the effect of legume consumption on CVD risk factors in order to understand their associations. The results revealed a prospective, significant inverse association between total legume consumption and CVD and coronary heart disease risk, whereas a nonsignificant association was observed with T2D and stroke. In the stratified analysis by legume subtypes, only nonsoy legumes were associated with lower risk of T2D. Unfortunately, owing to the paucity of studies analyzing legumes and CVD, it was not possible to stratify the analysis for these outcomes. Because of the high degree of heterogeneity observed for most of the outcomes and the few studies included in some analyses, further prospective studies are warranted to determine the potential role of legume consumption on CVD and T2D.

Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

OBJECTIVE

We conducted a systematic review and dose-response meta-analysis of prospective studies to summarize findings on the associations between intakes of soy, soy isoflavones, and soy protein and risk of mortality from all causes, cancers, and cardiovascular diseases.

METHODS

Online databases were systematically searched to identify relevant articles published earlier than May 2018. We applied restricted cubic splines using random-effects analysis to assess dose-response associations. Between-study heterogeneity was assessed by I2 value and Cochrane Q test. Potential publication bias was assessed by visual inspection of funnel plots and Begg regression test.

RESULTS

In total, 23 prospective studies with an overall sample size of 330,826 participants were included in the current systematic review and the meta-analysis. Soy/soy products consumption was inversely associated with deaths from cancers (pooled relative risk 0.88, 95% CI 0.79 to 0.99; P=0.03; I2=47.1%, 95% CI 0.0% to 75.4%) and cardiovascular diseases (pooled effect size: 0.85, 95% CI 0.72 to 0.99; P=0.04; I2=50.0%, 95% CI 0.0% to 77.6%). Such significant associations were also observed for all-cause mortality in some subgroups of the included studies, particularly those with higher quality. In addition, higher intake of soy was associated with decreased risk of mortality from gastric, colorectal, and lung cancers as well as ischemic cardiovascular diseases. Participants in the highest category of dietary soy isoflavones intake had a 10% lower risk of all-cause mortality compared with those in the lowest category. We also found that a 10-mg/day increase in intake of soy isoflavones was associated with 7% and 9% decreased risk of mortality from all cancers and also breast cancer respectively. Furthermore, a 12% reduction in breast cancer death was indicated for each 5-g/day increase in consumption of soy protein. However, intake of soy protein was not significantly associated with all-cause and cardiovascular diseases mortality.

CONCLUSIONS

Soy and its isoflavones may favorably influence risk of mortality. In addition, soy protein intake was associated with a decreased risk in the mortality of breast cancer. Our findings may support the current recommendations to increase intake of soy for greater longevity.

Dietary Flavonoids for Immunoregulation and Cancer: Food Design for Targeting Disease

Flavonoids, one of the most abundant phytochemicals in a diet rich in fruits and vegetables, have been recognized as possessing anti-proliferative, antioxidant, anti-inflammatory, and estrogenic activities. Numerous cellular and animal-based studies show that flavonoids can function as antioxidants by preventing DNA damage and scavenging reactive oxygen radicals, inhibiting formation of DNA adducts, enhancing DNA repair, interfering with chemical damage by induction of Phase II enzymes, and modifying signaling pathways. Recent evidence also shows their ability to regulate the immune system. However, findings from clinical trials have been mixed with no clear consensus on dose, frequency, or type of flavonoids best suited to elicit many of the beneficial effects. Delivery of these bioactive compounds to their biological targets through "targeted designed" food processing strategies is critical to reach effective concentration in vivo. Thus, the identification of novel approaches that optimize flavonoid bioavailability is essential for their successful clinical application. In this review, we discuss the relevance of increasing flavonoid bioavailability, by agricultural engineering and "targeted food design" in the context of the immune system and cancer.

Genistein Ameliorates Fat Accumulation Through AMPK Activation in Fatty Acid-Induced BRL Cells

Genstein is the most abundant phytoestrogen in soybean that was reported to play positive roles in menopausal syndrome and metabolic syndrome. In the present study, we investigated the effects and potential mechanisms of genistein against progression of nonalcoholic fatty liver disease (NAFLD) in BRL cells treated with fatty acid mixture (oleate/palmitate, 2:1 ratio). Our data demonstrated that genistein remarkably improved fatty acid mixture-induced hepatocelluler fat accumulation, inhibited upregulation of genes expression related to fatty acid synthesis, and derepressed those associated with fatty acid oxidation. In addition, the results displayed that genistein promoted the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) suppressed by fatty acid, which were significantly weakened by compound C, an AMPK inhibitor. Taken all together, genistein is capable to ameliorate fat accumulation through regulation of fatty acid metabolism mediated by AMPK activation in BRL cells. Further investigations are needed to verify the protective effects of genistein on NAFLD model in in vivo animal study or in vitro human cell lines along with absorption, distribution, metabolism, and excretion studies of genistein.

PRACTICAL APPLICATION

Genistein is able to ameliorate fat accumulation through regulation of fatty acid metabolism mediated by AMPK activation in vitro.

The impact of equol-producing status in modifying the effect of soya isoflavones on risk factors for CHD: a systematic review of randomised controlled trials

Recent studies suggest that the ability to produce equol, a metabolite of the soya isoflavone daidzein, is beneficial to coronary health. Equol, generated by bacterial action on isoflavones in the human gut, is biologically more potent than dietary sources of isoflavones. Not all humans are equol producers. We investigated whether equol-producing status is favourably associated with risk factors for CHD following an intervention by dietary soya isoflavones. We systematically reviewed randomised controlled trials (RCT) that evaluated the effect of soya isoflavones on risk factors for CHD and that reported equol-producing status. We searched PubMed, EMBASE, Ovid Medline and the Cochrane Central Register for Controlled Trials published up to April 2015 and hand-searched bibliographies to identify the RCT. Characteristics of participants and outcomes measurements were extracted and qualitatively analysed. From a total of 1671 studies, we identified forty-two articles that satisfied our search criteria. The effects of equol on risk factors for CHD were mainly based on secondary analyses in these studies, thus with inadequate statistical power. Although fourteen out of the forty-two studies found that equol production after a soya isoflavone intervention significantly improved a range of risk factors including cholesterol and other lipids, inflammation and blood pressure variables, these results need further verification by sufficiently powered studies. The other twenty-eight studies primarily reported null results. RCT of equol, which has recently become available as a dietary supplement, on CHD and its risk factors are awaited.

Probiotic Soy Product Supplemented with Isoflavones Improves the Lipid Profile of Moderately Hypercholesterolemic Men: A Randomized Controlled Trial

Background: Cardiovascular disease is the leading cause of worldwide morbidity and mortality. Several studies have demonstrated that specific probiotics affect the host’s metabolism and may influence the cardiovascular disease risk. Objectives: The aim of this study was to investigate the influence of an isoflavone-supplemented soy product fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus 416 on cardiovascular risk markers in moderately hypercholesterolemic subjects. Design: Randomized placebo-controlled double-blind trial Setting: São Paulo State University in Araraquara, SP, Brazil. Participants: 49 male healthy men with total cholesterol (TC) >5.17 mmol/L and <6.21 mmol/L Intervention: The volunteers have consumed 200 mL of the probiotic soy product (group SP-10¹⁰ CFU/day), isoflavone-supplemented probiotic soy product (group ISP–probiotic plus 50 mg of total isoflavones/100 g) or unfermented soy product (group USP-placebo) for 42 days in a randomized, double-blind study. Main outcome measures: Lipid profile and additional cardiovascular biomarkers were analyzed on days 0, 30 and 42. Urine samples (24 h) were collected at baseline and at the end of the experiment so as to determine the isoflavones profile. Results: After 42 days, the ISP consumption led to improved total cholesterol, non-HDL-C (LDL + IDL + VLDL cholesterol fractions) and electronegative LDL concentrations (reduction of 13.8%, 14.7% and 24.2%, respectively, p < 0.05). The ISP and SP have prevented the reduction of HDL-C level after 42 days. The C-reactive protein and fibrinogen levels were not improved. The equol production by the ISP group subjects was inversely correlated with electronegative LDL concentration. Conclusions: The results suggest that a regular consumption of this probiotic soy product, supplemented with isoflavones, could contribute to reducing the risk of cardiovascular diseases in moderately hypercholesterolemic men, through the an improvement in lipid profile and antioxidant properties.

Whole Soy Flour Incorporated into a Muffin and Consumed at 2 Doses of Soy Protein Does Not Lower LDL Cholesterol in a Randomized, Double-Blind Controlled Trial of Hypercholesterolemic Adults

BACKGROUND

Soy protein may reduce coronary heart disease (CHD) risk by lowering LDL cholesterol, but few studies have assessed whether whole soy flour displays a similar effect.

OBJECTIVE

The aim of this study was to assess the dose effect of whole soy flour incorporated into muffins on plasma LDL cholesterol in hypercholesterolemic adults.

METHODS

Adults aged 30-70 y (n = 243) with elevated LDL cholesterol (≥3.0 and ≤5.0 mmol/L) were stratified by LDL cholesterol and randomly assigned to consume 2 soy muffins containing 25 g soy protein [high-dose soy (HDS)], 1 soy and 1 wheat muffin containing 12.5 g soy protein and 12.5 g whey protein [low-dose soy (LDS)], or 2 wheat muffins containing 25 g whey protein (control) daily for 6 wk while consuming a self-selected diet. Fasting blood samples were collected at weeks 0, 3, and 6 for analysis of plasma lipids [total, LDL, and HDL cholesterol and triglycerides (TGs)], glucose, insulin, C-reactive protein (CRP), and isoflavones. Blood pressures also were measured. Dietary intake was assessed at weeks 0 and 4 with the use of 3 d food records. Treatment effects were assessed with the use of intention-to-treat analysis with multiple imputation and LDL cholesterol as the primary outcome.

RESULTS

In total, 213 (87.6%) participants completed the trial. Participants were primarily Caucasian (83%) and mostly female (63%), with a mean ± SD body mass index (in kg/m2) of 28.0 ± 4.6 and systolic and diastolic blood pressures of 122 ± 16 and 77 ± 11 mm Hg, respectively. Despite a dose-dependent increase in plasma isoflavones (P < 0.001), neither HDS nor LDS had a significant effect on LDL cholesterol compared with control (mean ± SEM changes: control, -0.04 ± 0.05 mmol/L; HDS, 0.01 ± 0.05 mmol/L; and LDS, -0.04 ± 0.06 mmol/L). There were no significant treatment effects on total or HDL cholesterol, TGs, CRP, homeostatic model assessment of insulin resistance, blood pressure, or the Framingham 10-y CHD risk score.

CONCLUSION

Consuming 12.5 or 25 g protein from defatted soy flour incorporated into muffins does not reduce LDL cholesterol or other CHD risk factors in hypercholesterolemic adults. This trial was registered at clinicaltrials.gov as NCT01547585.

Isoflavone pharmacokinetics and metabolism after consumption of a standardized soy and soy-almond bread in men with asymptomatic prostate cancer

Epidemiologic associations suggest that populations consuming substantial amounts of dietary soy exhibit a lower risk of prostate cancer. A 20-week randomized, phase II, crossover trial was conducted in 32 men with asymptomatic prostate cancer. The crossover involved 8 weeks each of soy bread (SB) and soy-almond bread (SAB). The primary objective was to investigate isoflavone bioavailability and metabolite profile. Secondary objectives include safety, compliance, and assessment of biomarkers linked to prostate carcinogenesis. Two distinct SBs were formulated to deliver approximately 60 mg aglycone equivalents of isoflavones per day. The isoflavones were present as aglycones (∼78% as aglycones) in the SAB whereas in the standard SB predominantly as glucosides (18% total isoflavones as aglycones). Compliance to SB (97% ± 4%) and SAB (92% ± 18%) was excellent; toxicity was rare and limited to grade 1 gastrointestinal complaints. Pharmacokinetic studies between SB and SAB showed modest differences. Peak serum concentration time (Tmax) was significantly faster with SAB meal compared with SB in some isoflavonoids, and AUC0 to 24 h of dihydrodaidzein and O-desmethylangolensin was significantly greater after an SB meal. An exploratory cluster analysis was used to identify four isoflavone-metabolizing phenotypes. Insulin-like growth factor-binding protein increased significantly by 41% (P = 0.024) with soy intervention. Findings from this study provide the necessary framework to study isoflavone-metabolizing phenotypes as a strategy for identification of individuals that might benefit or show resistance to cancer preventive strategies using dietary soy. A standardized SB used for future large-scale randomized clinical trials to affect human prostate carcinogenesis is feasible.

Soya products and serum lipids: a meta-analysis of randomised controlled trials

Soya proteins and isoflavones have been reported to exert beneficial effects on the serum lipid profile. More recently, this claim is being challenged. The objective of this study was to comprehensively examine the effects of soya consumption on the lipid profile using published trials. A detailed literature search was conducted via MEDLINE (from 2004 through February 2014), CENTRAL (The Cochrane Controlled Clinical Trials Register) and ClinicalTrials.gov for randomised controlled trials assessing the effects of soya on the lipid profile. The primary effect measure was the difference in means of the final measurements between the intervention and control groups. In all, thirty-five studies (fifty comparisons) were included in our analyses. Treatment duration ranged from 4 weeks to 1 year. Intake of soya products resulted in a significant reduction in serum LDL-cholesterol concentration, -4.83 (95% CI -7.34, -2.31) mg/dl, TAG, -4.92 (95% CI -7.79, -2.04) mg/dl, and total cholesterol (TC) concentrations, -5.33 (95% CI -8.35, -2.30) mg/dl. There was also a significant increase in serum HDL-cholesterol concentration, 1.40 (95% CI 0.58, 2.23) mg/dl. The I² statistic ranged from 92 to 99%, indicating significant heterogeneity. LDL reductions were more marked in hypercholesterolaemic patients, -7.47 (95% CI -11.79, -3.16) mg/dl, than in healthy subjects, -2.96 (95% CI -5.28, -0.65) mg/dl. LDL reduction was stronger when whole soya products (soya milk, soyabeans and nuts) were used as the test regimen, -11.06 (95% CI -15.74, -6.37) mg/dl, as opposed to when 'processed' soya extracts, -3.17 (95% CI -5.75, -0.58) mg/dl, were used. These data are consistent with the beneficial effects of soya proteins on serum LDL, HDL, TAG and TC concentrations. The effect was stronger in hypercholesterolaemic subjects. Whole soya foods appeared to be more beneficial than soya supplementation, whereas isoflavone supplementation had no effects on the lipid profile.

Relationships among fecal daidzein metabolites, dietary habit and BMI in healthy volunteers: a preliminary study

To investigate the relationships among fecal isoflavone metabolism, dietary habit and Body Mass Index (BMI), 15 healthy men and 15 healthy women were recruited and provided stool samples for analysis of ex vivo anaerobic incubation of fecal suspension with daidzein. A negative correlation was observed between BMI and the dihydrodaidzein (DHD) production in men, and between BMI and the equol production in women. There was a positive correlation between intake of soluble dietary fiber and the DHD production in men. The results suggest that dietary habits and BMI are related to the metabolic activity of isoflavonoids by fecal intestinal microbiota.

Soy provides modest benefits on endothelial function without affecting inflammatory biomarkers in adults at cardiometabolic risk

SCOPE

Systemic inflammation, endothelial dysfunction, and oxidative stress are involved in the pathogenesis of the metabolic syndrome (MetS). Epidemiological evidence supports an association between whole soy food consumption and reduced risk of cardiovascular disease (CVD). The objective of this randomized, controlled, cross-over study was to evaluate the effects of soy nut consumption on inflammatory biomarkers and endothelial function and to assess whether isoflavone metabolism to secondary products, equol, and/or O-desmethylangolensin (ODMA), modifies these responses.

METHODS AND RESULTS

n = 17 adults at cardiometabolic risk were randomly assigned to the order of two snack interventions, soy nuts, and macronutrient-matched control snack, for four weeks each, separated by a two week washout period. Outcome measures included biomarkers of inflammation, oxidative stress, and glycemic control (ELISA and clinical analyzers), endothelial function, and arterial stiffness (peripheral arterial tonometry (PAT)), and isoflavone metabolites (LC-MS/MS). Results revealed that consuming soy nuts improved arterial stiffness as assessed by the augmentation index using PAT (p = 0.03), despite lack of improvement in inflammatory biomarkers. Addition of equol and/or ODMA production status as covariates did not significantly change these results.

CONCLUSION

Soy nuts when added to a usual diet for one month provide some benefit on arterial stiffness in adults at cardiometabolic risk.

Characterization of black raspberry functional food products for cancer prevention human clinical trials

Our team is designing and fully characterizing black raspberry (BRB) food products suitable for long-term cancer prevention studies. The processing, scale-up, and storage effects on the consistency, quality, bioactive stability, and sensory acceptability of two BRB delivery systems of various matrices are presented. BRB dosage, pH, water activity, and texture were consistent in the scale-up production. Confections retained >90% of anthocyanins and ellagitannin after processing. Nectars had >69% of anthocyanins and >66% of ellagitannin retention, which varied with BRB dosage due to the processing difference. Texture remained unchanged during storage. BRB products consumed in a prostate cancer clinical trial were well accepted in sensory tests. Thus, this study demonstrates that two different BRB foods can be formulated to meet quality standards with a consistent bioactive pattern and successfully scaled up for a large human clinical trial focusing on cancer risk and other health outcomes.

Type and amount of lipids influence the molecular and textural properties of a soy soft pretzel

Altering baked goods by the addition of nutrient-rich ingredients, such as soy and ground almonds, affects the water and lipid distribution of the product and, subsequently, its final quality. Here, we studied how three lipid sources, shortening, canola oil, and ground almonds, affected texture and water distribution in a baked soy pretzel and the molecular mobility in the dough. Pretzel crumb from all formulations exhibited 40-43% moisture with a little more than half present as "freezable" water. Firmness and chewiness decreased with increased shortening and canola oil, whereas firmness and chewiness increased with additional almonds. In contrast, neither springiness nor cohesiveness was affected by the lipid quantity or source. Finally, magnetic resonance imaging of the soy pretzel dough revealed two or three populations of dough components that have distinct molecular mobilities. With increased lipid content, the mobility of each population increased in magnitude and heterogeneity. Interestingly, almonds had the smallest effect on the molecular mobility of the dough but had the largest effect on textural properties. These results provide quantitative insight into the mechanisms by which the lipid source can influence molecular properties that have textural implications for bakery products.

Physicochemical characterization and sensory analysis of yeast-leavened and sourdough soy breads

Sourdough fermentation has been shown to have numerous beneficial effects on bread quality, and nutritionally enhance soy-supplemented bread by altering isoflavone chemical forms. Given this, the objective of this study was to compare the loaf quality and shelf life of sourdough and yeast-leavened soy breads by various physical, thermal, and sensorial methods, and to assess the effects of fermentation by various microorganisms on isoflavone profile in dough and breads using high-performance liquid chromatography analysis. Sourdough fermentation yielded a less extensible dough compared to yeast-leavened soy dough (P < 0.001), and resulted in a harder bread crumb (P < 0.05) and lighter crust color (P < 0.001), compared to yeast-leavened soy bread (Y-B). Sensory analysis revealed a significantly higher overall liking of Y-B compared to sourdough soy bread (SD-B) (P < 0.001). Segmentation analysis of the cohort suggests that overall liking and bread consumption frequency may be determinants of Y-B or SD-B preference. SD-B and Y-B exhibited similar shelf-life properties. Despite significantly different enthalpies associated with the melting of amylose-lipid complexes, thermal analysis of the 2 soy breads stored for 10 d (ambient conditions) demonstrated no significant difference in water distribution and starch retrogradation (P < 0.05). Lastly, SD-B was determined to have 32% of total isoflavones occurring in the aglycone form compared to 17% in Y-B. These findings warrant further investigation of sourdough fermentation as a processing technique for quality and nutritional enhancement of soy-based baked goods.

Design and selection of soy breads used for evaluating isoflavone bioavailability in clinical trials

To modulate isoflavone aglycone composition within a soy functional food, soy ingredients were processed and evaluated in a soy bread system intended for clinical trials. A soy flour/soy milk mixture (SM) was boiled, fermented, steamed, or roasted prior to dough preparation. The isoflavone compositions of five processed SM and their corresponding breads combined with and without β-glucosidase-rich almonds were examined using HPLC. Isoflavone malonyl-glucosides (>80%) were converted into acetyl and simple glucoside forms (substrates more favorable for β-glucosidase) in steamed and roasted SM. Their corresponding breads had isoflavones predominately as aglycones (∼75%) with soy-almond bread with steamed SM being more consumer acceptable than roasted. Isoflavone composition in soy bread was stable during frozen storage and toasting. A suitable glycoside-rich soy bread (31.6 ± 2.1 mg aglycone equiv/slice) using unprocessed SM and an aglycone-rich soy-almond bread (31.1 ± 1.9 mg aglycone equiv/slice) using steamed SM were developed to evaluate fundamental questions of isoflavone bioavailability in clinical trials.

Isoflavone retention during processing, bioaccessibility, and transport by Caco-2 cells: effects of source and amount of fat in a soy soft pretzel

The impact of source and amount of lipid used to prepare a soy soft pretzel on the bioaccessibility and transport of isoflavones was investigated using the coupled in vitro digestion/Caco-2 human cell model. Pretzels were prepared without or with 2.9 or 6.0% exogenous lipid from either shortening, canola oil, ground almond, or ground hazelnut. The isoflavone backbone structure was stable during pretzel production, although there was partial conversion from malonyl and acetyl glucosides to simple glucosides and aglycones. Endogenous β-glucosidase activity in ground almond facilitated partial conversion of simple glucosides to aglycones during proofing, resulting in a slight decrease in bioaccessibility of isoflavones as compared with other sources of lipid. Amount and source of lipid did not affect bioaccessibility or uptake and metabolism of isoflavones by Caco-2 cells, although transport across the monolayer was greater with the lesser amount of shortening. These results suggest that the isoflavone structure, but not source or amount of lipid in a soy pretzel, may affect bioavailability of isoflavones.