Soy Breads Research Articles

Few case studies as ideas for zero-waste from food production and processing

Globally, the amount of agricultural waste is huge but not properly utilized yet. Precisely, about one billion tons of food produced for human consumption is wasted each year. This wastage global economy costs are estimated at US$ 1 trillion on annual level. The definition of food waste varies globally depending on where food waste occurs in the food supply and consumption chain, how it is generated, and what it covers. This review is a compilation of few different approaches in the context of zero waste from food production and processing. Soybean hull exploitation due to mass production of tofu, soymilk, edamame, tofu sausages and burgers, soy breads, soy pasta and soymilk yoghurts and cheeses, animal feed leads to a formation of high waste load. There are several available ways for soybean hull valorization: as a biofertilizer, as a substrate for microbial growth, as an adsorbent, for extraction of antioxidants and in our case for extraction of enzymes. The global consumption of coffee is approximately 10 million tons, resulting in a substantial production of spent coffee grounds (SCG) worldwide. However, this by-product has recently gained attention as a valuable source of usable compounds, particularly in our case for essential oils. During the cheese production process, the whey obtained as a by-product can be used as a raw material for development of new dairy products and in the same time to prevent the potential pollution of natural watercourses. The valorisation of the waste whey obtained in the cheese production by using it in the development of new products also contributes in the environment protection. In N. Macedonia, about 1000 tons of blood waste from industrial slaughterhouses flow into natural watercourses every year and it can find application in various industries. These are just a few examples that show that the possibilities for the implementation of the zero-waste concept are unlimited.

Type and Amount of Legume Protein Concentrate Influencing the Technological, Nutritional, and Sensorial Properties of Wheat Bread

Plant protein concentrates are used to enhance the nutritional quality of bread and to respond to the demand of consumers with respect to increased protein intake. In the present study, bread samples were produced using pea protein concentrate (PP) and soy protein concentrate (SP) substituting wheat flour by 5%, 10%, and 15%. The protein levels were between 1.2- and 1.7-fold (PP) and 1.1- and 1.3-fold (SP) higher than the control bread. The incorporation of 10% and 15% PP allowed for the achievement of a “high protein” claim. Water absorption was correlated with the protein contents of the breads (r = 0.9441). The decrease in bread volume was higher for the PP than SP incorporations, and it was highly negatively correlated with the protein content (r = −0.9356). Soy breads had a softer crumb than pea breads. The total change in crumb colour was higher in the PP than SP breads. The soy breads had an overall acceptability between 6.3 and 6.8, which did not differ (p > 0.05) from the control. PP breads were statistically less liked (p < 0.05). The results underlined that the choice of the type and amount of protein concentrates influenced the bread properties differently.

Adherence to guidelines of healthy diet is low in patients with diabetes clinical inertia

Background: Diabetes is one of the most prevalent metabolic disorders affecting 382 million people worldwide and 8.7% of Iranian population aged between 15 and 64 years. We investigated adherence to healthy diet guidelines in patients with diabetes clinical inertia. Methods: This cross-sectional observational study was performed on 200 patients with diabetes (mostly type 2 diabetes) involved in poor glycemic control. The patients were recruited from a Diabetes Care Clinic in Iran. Biographic and medical information was obtained by interview. A semi-quantitative food frequency questionnaire was used to estimate consumption of food items. Data on plasma glucose and lipids was obtained from patients’ dossiers in the clinic. Individuals were excluded if their laboratory tests had been carried out earlier than 3 months prior to the study. Results: Mean hemoglobin A 1c (HbA 1c ) was 8.3 ± 1.9%, 62.7% of the patients had HbA 1c ≥7.5%, and 88.5% had at least one form of dyslipidemia. Consumption of dairy, fruit, and vegetables was lower than dietary recommendations for healthy individuals in 55%, 54.5%, and 83%, respectively, but 72% consumed high-fiber breads. Among the investigated dietary factors only consumption of high-fiber breads was significantly associated with lower HbA 1c (P=0.03). Consumption of none of dietary items was associated with low- and high-density lipoproteins, but there were significant associations between triglycerides and consumption of vegetables (P=0.004), fish (P=0.02), soy (P=0.02), vegetable oils (P=0.047), and high-fiber breads (P=0.04). Conclusion: The patients adhered poorly to the guidelines of healthy diet. However, even if following these guidelines is not effective in the control of hyperglycemia in patients with diabetes clinical inertia, it may help to attenuate hypertriglyceridemia.

Decreased fat accumulation in 3T3‐L1 pre‐adipocytes treated with extracts of heat‐processed soy flour and breads

SummaryThe potential anti‐adipogenic effects of gluten‐free soy breads made from germinated soybean (GS), steamed soybean (SS) or roasted soybean (RS) were evaluated in an in vitro adipocyte cell model. GS and RS increased the total phenolic (TP) and total flavonoid (TF) contents of flours compared with the raw soybean (NS) flour. RS and GS had the highest TP (1.04 GAE mg g−1) and TF (0.92 CAE mg g−1) contents. Baking increased the TP content of breads, 0.09–0.26 GAE mg g−1, compared with the flours. Fermentation during breadmaking increased the DPPH scavenging activities compared with the flours. The ABTS scavenging exhibited similar patterns to those of DPPH. Lipid accumulation in 3T3‐L1 cells shows that the alcoholic extracts (100 μg mL−1) of SS flour and bread decreased adipocyte differentiation by 1.6‐ and 2.1‐fold, respectively, compared with control. SS bread extract substantially downregulated the adipogenesis‐related genes such as acetyl‐CoA carboxylase and glycerol‐3‐phosphate dehydrogenase.

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.

Abstract LB-188: Isoflavone pharmacokinetics and metabolism after consumption of soy and soy-almond bread in men with asymptomatic prostate cancer.

Abstract Background: Soy phytochemicals, particularly isoflavones, are hypothesized to have anti-prostate cancer activity. Soy isoflavones are present predominantly as glucosides but when combined with β-glucosidase activity in almond meal, a greater conversion to aglycones has been observed. We hypothesized that soy bread will serve as an excellent source of soy polyphenols and that an aglycone-rich soy-almond bread (SAB) compared to a glycoside-rich soy bread (SB) will demonstrate greater bioavailability of soy isoflavones. Methods: SB and SAB were fed in a 20 week randomized phase II cross-over trial involving 32 men with asymptomatic metastatic prostate cancer and escalating prostate specific antigen (PSA). Isoflavones were quantitated by HPLC in soy breads and isoflavone metabolites in 24h urine. HPLC-tandem mass spectrometry evaluated isoflavone pharmacokinetics in plasma. Biomarkers were determined by chemiluminescence-based assays. Results: The aglycone composition in the SB and SAB was 18% and 78%, respectively. Compliance was 95±14%, toxicity rare and limited to grade I GI complaints (NIH_NCI criteria). Urinary isoflavone patterns over 24hours revealed that isoflavonoid metabolites were significantly greater with soy bread consumption. Plasma pharmacokinetics following a test meal showed that daidzein (p=0.028) and genistein (p=0.010) absorption was significantly faster from the aglycone-rich SAB. Interestingly, PSA doubling time was prolonged compared to pre-enrollment, in 60% of men (n=30) with soy intervention. Conclusions: Bread is an excellent vehicle for the delivery of soy phytochemicals with outstanding compliance. Modification of soy bread with a source of β-glucosidase may enhance the initial absorption rates of isoflavones. Food products, such as SAB, with consistent and stable composition of phytochemicals can be developed that are appropriate for long-term chemoprevention studies in humans or as an adjunct to therapy. Citation Format: Jennifer H. Ahn-Jarvis, Steven K. Clinton, Elizabeth M. Grainger, Kenneth M. Riedl, Steven J. Schwartz, Yael Vodovotz. Isoflavone pharmacokinetics and metabolism after consumption of soy and soy-almond bread in men with asymptomatic prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-188. doi:10.1158/1538-7445.AM2013-LB-188

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.

Effect of soy milk powder addition on staling of soy bread

Effect of soy milk components (soluble fibre (SF), insoluble fibre (ISF), soy protein) on physicochemical properties (crust and crumb colour, water activity, total moisture content, “freezable” water (FW), “unfreezable” water (UFW), amylopectin recrystallisation (ARC), stiffness and firmness) of soy breads stored for 7days was studied. By the end of storage ISF additions significantly increased ARC (from 0.01 to 0.57W/g), whereas SF additions (0.30W/g) retarded staling with respect to soy flour bread (0.39W/g). Principal Component Analysis (PCA) of all the different treatments and formulations indicated that SMP addition resulted in the lowest firmness and least amylopectin retrogradation at the end of storage, likely due to the synergistic effect of soluble fibre, partly denatured soy proteins and lipid content of this ingredient.

Tracking isoflavones: From soybean to soy flour, soy protein isolates to functional soy bread

Soybean seeds with three different levels (low, intermediate and high) of isoflavones were processed to soy flour and soy protein isolates (SPIs) and developed into functional soy breads. The effect of factors involved in all steps of the process was investigated by tracking the composition and concentration of native forms of isoflavones. The total isoflavone contents were 8033.3, 10570.1 and 15169.0 nmol/g DM (dry matter) in the three soybeans; 13201.5, 20034.4 and 26014.3 nmol/g DM in defatted soy flours; 9113.2, 13274.6 and 17918.3 nmol/g DM in the SPI; 2782.7, 4081.4 and 5590.3 nmol/g DM in soy breads, respectively. The bread making processes did not affect the total isoflavone content, but changed glucosides/acetylglucosides to aglycones. Malonylglucosides were stable prior to baking but degraded to acetylglucosides and further to glucosides during baking. Our results provide critical information for the production of functional soy breads that contain varying amounts of soy isoflavones.

Functionality of Soymilk Powder and Its Components in Fresh Soy Bread

The physicochemical changes upon addition of soymilk powder (SMP) to soy bread were investigated. Two-pound loaves of soy bread were produced with components (soluble fiber [SF], insoluble fiber [ISF], soy protein) that mimic those levels contributed by SMP. Soy flour and soy flour/SMP soy breads served as controls. The following were determined for all breads produced: physical properties (loaf volume, crust, and crumb color); chemical compositions (SF and ISF contents, protein and ash contents); and physicochemical properties (water activity, total moisture content by thermogravimetric analysis [TGA], "freezable" water [FW], "unfreezable" water [UFW] content by DSC, stiffness at 25 degrees C by dynamic mechanical analysis [DMA], and firmness with Instron testing machine). SMP contained significant amounts of SF aside from the ISF fraction and mostly denatured soy protein. SMP addition to soy bread formulation significantly decreased loaf volume with respect to control soy bread, which can be attributed to the ISF and SPI contents of this ingredient. Other effects of SMP were found to be lighter and yellowish crumb color, darker crust color, and increase in firmness, as well as no change in moisture content, FW and UFW contents, water activity, and stiffness parameters.

Molecular Changes in Soy and Wheat Breads during Storage as Probed by Nuclear Magnetic Resonance (NMR)

Addition of raw ground almond has been shown to improve loaf quality (e.g., loaf specific volume) of soy bread. To better understand the effects of almond addition to soy bread and to follow these through storage, nuclear magnetic resonance spectroscopy relaxation times and cross-relaxation experiments were performed. Spin-spin relaxation times of water protons were similar for the two soy breads, and therefore changes of water interactions with the other components of the soy breads (with and without almond) were not considered to be major contributors to the differences in loaf quality observed between these breads. Additionally, T2 values of water protons were found to have a similar decreasing trend during storage, especially up to day 3, for all of the products studied. On the other hand, during storage, lipid proton relaxation times exhibited only small changes in wheat and regular soy bread, whereas the soy-almond bread showed a major decrease of lipid proton mobility in particular after day 3 and up to day 10. These findings may indicate that, after a few days of storage, the lipid fraction contributes to better plasticization of the soy bread with almond, which can affect acceptability and storage stability of the final product. Thus, the higher amount of lipids introduced in the almond-enriched soy bread is likely to be responsible for the improved loaf quality and may significantly affect shelf stability of the soy-containing product.

Characterization of water distribution in bread during storage using magnetic resonance imaging

A soy bread of fully acceptable quality and containing 49% soy ingredients (with or without 5% almond powder) has been recently developed in our laboratory. An investigation on water distribution and mobility, as probed by proton signal intensity and T2 magnetic resonance images, during storage was designed to examine possible relations between water states and hindered staling rate upon soy or soy-almond addition. Water proton distribution throughout soy-containing loaves was found to be very homogeneous in fresh breads with and without almond, with minimal water migration occurring during prolonged storage. In contrast, traditional wheat bread displayed an inhomogeneous water proton population that tended to change (with higher moisture migration towards the outer perimeter of the slice) during storage. Similar results were found for water mobility throughout the loaves, as depicted in T2 images. On intensity images of all considered bread varieties, the outer perimeter corresponding to the crust exhibited lower signal intensity due to decreased water content. Higher T2 values were found in the crust of soy breads with and without almond, which were attributed to lipids. The results indicated that the addition of soy to bread improved the homogeneous distribution of water molecules, which may hinder the staling rate of soy-containing breads. However, incorporation of almond had little effect on the water proton distribution or mobility of soy breads.

Production of a Soy Protein Product Designed to Promote Heart Health

Soybeans gained attention as food constituents with added health benefits when soy protein intake was linked to cholesterol lowering. A FDA Health Claim for soy protein as a diet component that may reduce heart disease risk, when part of a diet low in sat fat & cholesterol further promoted consumption. As CVD is the primary cause of death in the US, soy protein sources that meet the Health Claim of 25g/soy prot/day (four 6.25g serving) were desired. This study was designed to produce yeast-leavened soy bread that would be a good source of soy protein (FDA) meet AHA guidelines & have acceptable sensory characteristics. Breads containing 3.13 (low soy) & 6.25g (high soy) soy prot/50g serving were developed. Soy breads were compared to whole wheat control breads. Sensory results showed no sign. diff. in taste, aftertaste & aroma between low soy bread & control. High soy bread was rated sign. lower for these attributes (p<0.05). Taste panelists who were frequent consumers of soy reported sign. increased acceptability of soy bread (p<0.05). These results suggest soy protein intake recommendations may be met by consumption of soy bread & increased acceptability of soy products increases with consumption.

Examination of the Functional Properties of a Heart Healthy Soy Bread

Soy protein consumption has been advocated as a means by which one may lower the risk of developing cardiovascular disease. The purpose of this study was to evaluate the functional characteristics of soy breads designed to meet the FDA Health Claim for soy protein. Two soy breads were compared to a control wheat bread: Low soy (3.13 g/soy protein/50 gram serving) & high soy (6.25 g/soy protein/serving). Moisture losses were lower in the soy breads compared to control and loaf volume decreased significantly with increasing soy amounts (P<0.05), resulting in a compact and dense crumb structure. Texture profile analysis revealed a significant increase in hardness, chewiness and gumminess in the high soy bread (P<0.05) and springiness decreased as soy protein increased (P<0.05). GC-MS was used to evaluate volatile flavor and aroma compounds. Compounds detected in highest concentrations in all breads were ethanol, 2-methyl-1-propanol, 3 methyl-1-butanol, 1-propanol, 3-hydroxy, 2-butanone, 2,3-butanedione, ethyl acetate and 2-methylpropanol. Hexanal, 2-pentylfuran and pentanal were the most frequently reported volatile compounds in the soy products.

Dietary phytoestrogen intake in mid-life Australian-born women: relationship to health variables

Objectives To estimate the dietary intake of isoflavone-rich foods in a population-based cohort of Australia-born women, and to investigate whether a high intake of isoflavone-rich foods is associated with health-related variables.Method The study considered a population-based cohort of Australian-born women aged 51–62 years, with interviews, blood and physical measurements taken in their own homes. Food frequency questionnaires included usual eating habits and isoflavone-rich foods.Results In total, 354 women (98%) returned both dietary questionnaires. Some 222 women (62%) reported consuming isoflavone-rich foods. Soy breads and milk provided the most servings per month. The mean intake of isoflavones calculated from soy beans, soy grits, tofu, soy milk, and soy and linseed bread in the whole cohort was 17 (standard deviation 35, range 0–340) mg/day. Fifty-one women (14%) consumed > 40 mg isoflavone/day. Compared with the rest of the cohort they had higher intakes of fruit, energy, protein, vitamins and minerals; ate a greater variety of vegetables; were more likely to exercise; were less likely to smoke; had lower mean body mass index, waist and hip measures and higher bone mineral density of the femoral neck; and had lower negative mood scores (all p < 0.05).Conclusion Australian-born women in Melbourne have a wide range of intake of isoflavone-rich foods. For those with a high intake it seems to be one component of a healthier life-style. It is thus not possible to assign particular health benefits to the one dietary component.

Soy flour in European‐type bread

Effect of soy flour, soy protein concentrate, and isolate on dough and loaf properties of breads produced from flour, yeast, salt, and water with no shortening or added improvers was investigated. Wheat flour, rye flour, and mixtures of the two were included in the studies. Three wheat flours, varying in baking quality and extraction, ash content 0.65 and 0.80%, were used; 1.5, 3, and 5% soy products, flour basis, were added. Water absorption increased 3.8–4.7% at the 3% soy level and 6.1–7.3% at the 5% level of soy product addition. Dough development time and stability were increased and dough softening reduced. Dough gassing power increased ca. 7–25%. By using a shorter proofing time, more intensive mixing, and the sponge dough process, loaves only slightly smaller in volume than the control were obtained at the 3% soy level. Panel evaluations scored bread highest with 1.5 or 3% soy flour and that with 3 or 5% soy protein concentrate as lowest, but acceptable. Use of 2% lard as shortening, or 2% lard plus emulsifier, produced soy breads of excellent quality and ca. 25% higher loaf volume than controls.