Possible interaction between pectin and gluten alters the starch digestibility and texture of wheat bread

This study incorporated citrus pectin in wheat bread, aiming to develop breads with both desirable texture and slow starch digestibility. Results showed that starch digestibility in wheat bread decreased over the addition of pectin, and the maximum starch digested amount decreased by 6.6 % after the addition of 12 % pectin (wheat flour weight basis). The addition of pectin transferred part of the rapidly digestible starch into slowly digestible starch, and reduced the binding rate constant between slowly digestible starch and digestive enzymes, resulting in overall reduced starch digestibility. Furthermore, the addition of 4 % pectin contributed to the development of wheat bread with softer texture and increased specific volume. Mechanistically, the lowered starch digestibility of wheat bread after the pectin addition was due to (1) residual outermost swollen layer of starch granules, (2) protein and pectin interactions, and (3) increased short-range ordering of starch. This study, therefore, suggests that the addition of an appropriate amount of citrus pectin has the potential to develop bread with both a low glycemic index and desirable texture.

A comparative study of magnetic field on the maximum ice crystal formation zone and whole freezing process for improving the frozen dough quality

Magnetic field individually applied on the maximum ice crystal formation zone (MMF) and the whole freezing process (WMF) was compared to improve the quality of multiple freezing-thawing treated dough. All treatments showed that the breadmaking performances of magnetic field-assisted freezing were better than the conventional freezing. Especially, the WMF-treated breads exhibited higher resilience and lower firmness than MMF-treated breads. WMF treatment made dough remained a continuous and compact gluten-starch matrix while the starches and glutens got separated in MMF-treated dough. It could keep the gluten macropolymer from freezing-induced depolymerization with the decreased free sulfhydryl by 7.09% and more ordered secondary structure. WMF had positive effects on the homogeneous water distribution and high water-binding ability in frozen dough where the freezable water decreased from 32.47% to 30.77%. This comparative study of different freezing stages provided new insights into the better application of magnetic field on frozen dough-based food.

Organic acids in bread-making affecting gluten structure and digestibility

Although wheat gluten has remarkable technological properties, it can induce adverse immune reactions in susceptible individuals, such as wheat allergy and celiac disease. Technological processing and some additives on bread formulation can modify gluten physicochemical structure, but the knowledge about the impacts on the digestibility and immunogenicity of gluten is limited. The present study aimed to study the effect of adding organic acids (acetic or ascorbic) on dough rheological properties and bread technological characteristics. In addition, breads were subjected to in vitro digestion and the digesta were analyzed by confocal microscopy, SDS-PAGE and ELISA immunoassay. Acetic acid resulted in a decrease in dough development time up to 44 % and a reduction in stability up to 20 %. Ascorbic acid, present in vinegar, on the other hand, increased elastic modulus (G') and resistance to extension of dough. After the in vitro digestion, SDS-PAGE indicated that protein degradation started in the gastric phase, with the generation of low molecular weight peptides. Accordingly, ELISA immunoassay suggested a great reduction in immunogenic gliadin content from oral to gastric phase. At the end of the intestinal phase, samples with ascorbic acid did not differ from the control, while vinegar addition indicated a reduction in gluten immunogenicity with a reduction of about 44 % in immunogenic gliadin content compared to the control. Results show a window of opportunity in the modulation of wheat bread formulation with reduced allergenicity, while maintaining the technofunctional properties.

A study on the use of sorrel seed flour (Hibiscus sabdariffa) for improving functionality of wheat flour bread

Bread presents one of the easiest opportunities as a food vehicle for delivery of nutritional and health-promoting benefits to large segments of the world population. However, its low nutritional status due to lack of balance of essential amino acids and inadequate macro- and micronutrients has necessitated recent interest in the development of high-protein hybrid breads (HPHB). Sorrel seed, an underutilized, neglected protein-rich seed holds promising nutritional and antioxidant potentials as source of good quality protein, dietary fibre and bioactive compounds. Furthermore, germination of plant seeds increases the bioavailability of these nutritional and bioactive compounds. Hence, this study has investigated the influence of germination time on nutritional, and functional properties of sorrel seed flour. Further, the amino acid profile, dietary fibre and rheological functionality of wheat-germinated defatted sorrel seed bread were assessed. The sorrel seed was germinated for 24-48 h and defatted. Thereafter, the germinated defatted sorrel seed flours were used to partially replace wheat flour using a linear replacement (w/w) of 95-80% wheat (W) and 5-20% germinated defatted sorrel seed (GS) flours to obtain W95:GS5; W90:GS10, W85:GS15 and W80:GS20. These composite flours and 100% wheat flour (control) were used to produce breads using standard recipe and methods. Results showed significant increase (P < 0.05) in crude protein, dietary fibre and mineral contents after 24 and 48 h germination of sorrel seed. While 24 h germination significantly (P < 0.05) increased WAC from 93.75% to 103.13%, further germination (48 h) caused a reduction of 26.67% (from 93.75 to 68.75%). In vitro protein digestibility of wheat flour decreased significantly (P < 0.05) as supplementation of germinated defatted sorrel seed flour increased. Supplementation of wheat flour with germinated defatted sorrel seed flour in bread production resulted in 51.84-121.42% significant (p < 0.05) increase in the protein content of wheat bread. Similarly, total essential amino acids, dietary fibre, mineral, and ash contents followed the same increasing trend. The in-vivo biological value which ranged from 82.10 to 89.40% was significantly higher (p < 0.05) than 58.30% obtained for the control (100% wheat bread) Thus, inclusion of germinated defatted sorrel seed flour in bread production may serve as a low-cost nutritional supplement for enhancing the nutritional profile and functional benefits of wheat bread.

Influence of Enzymatic Hydrolysis on Composition and Technological Properties of Apple Pomace and Its Application for Wheat Bread Making

The aim of this work was to evaluate the influence of enzymatic hydrolysis on dietary fiber, phenolic compounds and technological properties of apple pomace as wheat bread supplement. Apple pomace was hydrolyzed with Viscozyme® L, Pectinex® Ultra Tropical, Celluclast® 1.5 L for 1 and 5 h. Soluble (SDF) and insoluble (IDF) dietary fiber, reducing sugars and the total phenolic contents (TPC), along with the technological properties (water and oil retention capacities, solubility index, emulsion stability) of treated apple pomace were evaluated. The prebiotic activity of apple pomace water-soluble fraction on two probiotic strains Lactobacillus acidophilus DSM 20079 and Bifidobacterium animalis DSM 20105 was investigated. Treatment with Celluclast® 1.5 L increased SDF, reducing sugars, SDF/IDF ratio and decreased IDF of apple pomace. While treatment with Viscozyme® L, Pectinex® Ultra Tropical increased reducing sugars, solubility index and TPC, but in most cases reduced oil and water retention capacities, decreased SDF and IDF content. All apple pomace extracts promoted growth of probiotic strains. Addition of 5% of apple pomace hydrolyzed with Celluclast® 1.5 L did not have negative impact on wheat bread, while addition of other enzymatically hydrolyzed apple pomaces decreased pH, specific volume and porosity of wheat bread. Obtained results suggest that apple pomace enzymatically hydrolyzed with Celluclast® 1.5 L can be potentially used for wheat bread supplementation with dietary fiber.

The impacts of salt reduction strategies on technological characteristics of wheat bread: a review

Increased consumption of sodium is considered as the leading cause of cardiovascular disease and hypertension. Processed foods like bakery products are considered as the main source of sodium intake. Regarding the high consumption ratio of wheat bread, it is counted as the main contributor of sodium intake by the European food Safety Authorization and World Health Organization. Consequently, its salt reduction is considerably important to postpone adverse effects induced by sodium. Salt is used in wheat bread as a technological and sensory improver. Different salt reduction strategies (e.g. sodium free mineral salts, hollow salts, uneven salt distribution, amino acids and plant based salt boosters) had been assessed to reduce the sodium content in wheat bread. Despite their potential efficiency to partially imitate the technological and sensorial characteristics of salt in wheat breads, challenges also existed which may restrict their consumption level. Considering the importance of wheat bread in our daily diet, its high sodium content and the critical role of salt in its technological characteristics this study is aimed to review the influence of different salt reduction strategies in wheat bread from technological perspective.

Elucidation of the non-volatile fingerprint in oven headspace vapor from bread roll baking by ultra-high resolution mass spectrometry

Untargeted research on vapor arising during the thermal processing of food has so far focused on volatile aroma compounds. In this study, we present an oven atmosphere sampling strategy to trap headspace aerosols along with semi- and non-volatile molecules liberated during the baking of wheat bread rolls. The collected vapor condensate was analyzed for its molecular fingerprinting using direct infusion ultra-high resolution mass spectrometry. We detected up to 4,700 molecular species in a vapor sample from bread rolls baked at 230 °C for 15 min. Beyond the global profiling of the underlying matrix, our method can follow complex reaction cascades during the baking process, such as the formation of advanced glycation end-products like maltosine through the interface of trapped vapor. Further, process parameters such as baking temperature and duration were used to model the dynamic liberation of molecules to the oven atmosphere by a response surface methodology approach.

Co-extruded wheat/okra composite blends result in soft, cohesive and resilient crumbs rich in health-promoting compounds

This work investigates the partial solubilization of cell wall polysaccharides in okra flours and the changes in the profile of free and bound phenolics through twin-screw extrusion. The comparison between extruded wheat flour-native okra flour (EWF-OF) and extruded wheat flour-extruded okra flour (EWF-EOF) composite blends revealed that extrusion led to an increase of soluble dietary fiber from 7.76 to 10.02 g/100 g. Extrusion of okra also resulted in a significant increase of free and bound phenolic acids, the latter consisting mostly of ferulic acid, as well as the thermal degradation of free epigallocatechin, and the binding of a small portion of quercetin-3-O-glucoside likely to a carbohydrate fraction. Bread crumbs from EWF-EOF (at 15% replacement level) exhibited a significantly lower hardness and higher elasticity, cohesiveness and resilience (from 28.28 N, 0.94, 0.49 and 0.17 to 7.54 N, 0.99, 0.70 and 0.35, respectively), which closely resembled the textural attributes of wheat bread.

Investigation of the anti-hyperglycemic and antioxidant effects of wheat bread supplemented with onion peel extract and onion powder in diabetic rats

AIM

Onion is one of the commonly cultivated and consumed vegetables rich in nutrients and phytochemicals. Various nutraceuticals are found in the outer fleshy layers and dry peel of onion which usually is treated as a common biowaste. Diabetes mellitus is a leading non communicable disease causing hyperglycemia and increased production of free radicals that potentially disrupts antioxidant enzymatic activity. Considering global consumption of wheat, the present study was designed to evaluate the anti-hyperglycemic and antioxidant effects of wheat bread supplemented with onion peel extract (OPE) or onion powder (OP) on diabetic rats.

METHODS

In this study, ethanolic extract of onion peel and onion bulb were prepared separately. Male Sprague Dawley rats were divided into 6 groups (n = 7). Different regimens of supplemented wheat bread (OPE (1% and 3%) and OP (5% and 7%)) were given to diabetic rats for eight weeks, plain bread was used as the control. Blood glucose level, body weight and activities of SOD, CAT, GPx, GR, GSH and MDA in the liver and kidney tissues were evaluated. Statistical analysis was performed using SPSS Version (25) and Dunnett's multiple comparison test.

RESULTS

Bread supplemented with 1% and 3% onion peel extract and 7% onion powder significantly reduced blood glucose levels and MDA in the treated rats compared with the control group diabetic rats. Body weight of diabetic rats was reduced for control group, while onion supplemented diet improved the body weight of treated rats. Onion supplementation also brought significant improvement in antioxidant enzyme activities among the treated diabetic rats.

CONCLUSION

These findings suggested that onion supplementation is effective in lowering blood glucose and could potentially aid in protecting organs from oxidative stress.

Sourdough fermentation of whole and sprouted lentil flours: In situ formation of dextran and effects on the nutritional, texture and sensory characteristics of white bread

Exopolysaccharides produced in situ by lactic acid bacteria during sourdough fermentation are recognized as bread texture improvers. In this study, the suitability of whole and sprouted lentil flours, added with 25% on flour weight sucrose for dextran formation by selected strains during sourdough fermentation, was evaluated. The dextran synthesized in situ by Weissella confusa SLA4 was 9.2 and 9.7% w/w flour weight in lentil and sprouted lentil sourdoughs, respectively. Wheat bread supplemented with 30% w/w sourdough showed increased specific volume and decreased crumb hardness and staling rate, compared to the control wheat bread. Incorporation of sourdoughs improved the nutritional value of wheat bread, leading to increased total and soluble fibers content, and the aroma profile. The integrated biotechnological approach, based on sourdough fermentation and germination, is a potential clean-label strategy to obtain high-fibers content foods with tailored texture, and it can further enhance the use of legumes in novel foods.

Yoghurt and curd cheese addition to wheat bread dough: Impact on in vitro starch digestibility and estimated glycemic index

The effect of yoghurt and curd cheese additions on pasting properties, starch digestibility and estimated glycemic index of wheat bread were studied. Yoghurt and curd cheese incorporations (6% up to 25% w/w) promoted considerable changes on starch performance based on gelatinization and final dough consistency properties. These changes led to a significant impact on starch digestibility, reducing significantly the rapidly digestible starch while increasing the resistant starch. The estimated glycemic index reflected the changes promoted on starch performance from both dairy products addition, at higher level tested (25%): a significant reduction of around 30% for yoghurt bread and 38% for curd cheese bread, was obtained, resulting in medium to low (55-69) glycemic index breads. Correlations were found between pasting properties, starch digestibility and glycemic index, revealing that the effects observed are proportional to the levels of dairy products added. Microstructure images of the starch granules supported these findings.

Application of Lactic Acid Bacteria for Coating of Wheat Bread to Protect it from Microbial Spoilage

Comparative study of four edible coatings of wheat bread containing lactic acid bacteria showed that coating with Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophilus, sodium alginate, whey and glycerol had the best protective properties against microbial spoilage. The viability of lactic acid bacteria was high in the coating containing alginate and whey: a loss in viability was in one - three orders of magnitude lower from initial concentration of 10⁸-10⁹ CFU/g coating after 120 h of storage. Wheat bread with edible coating did not differ by organoleptic assessment from control. The application of edible coating containing lactic acid bacteria to wheat bread diminished the number of mesophilic aerobic and facultative aerobic bacteria in the bread crust and protected it from contamination of mycelium fungi of genera Aspergillus and Penicillium that could preserve wheat bread from mold spoilage and increase shell life.

Impact of sodium reduction strategies on volatile compounds, sensory properties and consumer perception in commercial wheat bread

The efficacy of two sodium reduction strategies in preserving sensory profile and consumer liking of yeasted wheat bread was tested, by combining sensory data, aroma compounds and consumer investigations. The use of (i) a reduced-sodium salt substitute, Pansalt® (NaCl 57%, other salts and minor ingredients) at 1.5%, and (ii) the heterogeneous NaCl distribution (average level of 1%) leading to enhanced saltiness by taste contrast, were compared with standard (1.5%) and reduced (1.0%) addition of NaCl. The heterogeneous NaCl distribution was effective in preserving saltiness. Salt substitution with Pansalt® was less effective but preserved the overall flavour. Higher amount of Maillard reaction volatile products, associated with more intense toasted odour of the crust, was found in breads with higher NaCl content. The consumer survey highlighted satisfactory results of Pansalt® use for 58% of the respondents (equal or higher liking and purchase intention). Heterogeneous salt distribution was effective for 31% of consumers.

Development of high-fiber wheat bread using microfluidized corn bran

Microfluidized corn bran is an excellent source of dietary fiber but has not been used to develop high-fiber bread. To develop such bread, it replaced 18, 20, and 22% of flour in the control white bread formula. At the standard water content, the amount of water required to develop a dough consistency of 500 Brabender Units in farinograph tests, the resulting bread had worse microstructure and textural properties, and much smaller loaf volume than the control bread. Instead of using existing physical, chemical and enzymatic methods to reduce the deteriorating effects of bran, we resolved the issue effectively by optimizing the water content in bread formulas. For the three levels of bran addition, when the water content was increased from its standard values of 38.3, 38.6, 38.8% to 40.8, 41.9, and 44.0%, respectively, the obtained loaves exhibited similar microstructure, specific loaf volume, and textural properties to the control bread.

Effect of fiber sources on fatty acids profile, glycemic index, and phenolic compound content of in vitro digested fortified wheat bread

In this study, some dietary fiber (DF) sources were investigated as fortifiers of wheat bread: oat (OB), flax (FB), and apple (AB). Adding oat and flax fibers to bread significantly changed the fatty acid profiles. OB was highest in oleic acid (33.83% of lipids) and linoleic acid (24.31% of lipids). Only in FB, γ-linolenic fatty acid was present in a significant amount-18.32%. The bioaccessibility trails revealed that the DF slow down the intake of saturated fatty acids. PUFA were least bioaccessible from all fatty acids groups in the range of (72% in OB to 87% in FB). The control bread had the greatest value (80.5) and was significantly higher than values for OB, FB, and AB in terms of glycemic index. OB, FB and AB addition led to obtain low glycemic index. AB had a significant highest value of total phenolic (897.2 mg/kg) with the lowest values in FB (541.2 mg/kg). The only significant lowering of caloric values in this study was observed in AB. The study could address the gap in the area of research about taking into consideration glycemic index, fatty acid profile and phenolic content in parallel in terms of DF application in breads.

Analytical methods for volatile compounds in wheat bread

Bread aroma is one of the main requirements for its acceptance by consumers, since it is one of the first attributes perceived. Sensory analysis, crucial to be correlated with human perception, presents limitations and needs to be complemented with instrumental analysis. Gas chromatography coupled to mass spectrometry is usually selected as the technique to determine bread volatile compounds, although proton-transfer reaction mass spectrometry begins also to be used to monitor aroma processes. Solvent extraction, supercritical fluid extraction and headspace analysis are the main options for the sample treatment. The present review focuses on the different sample treatments and instrumental alternatives reported in the literature to analyse volatile compounds in wheat bread, providing advantages and limitations. Usual parameters employed in these analytical methods are also described.

Effect of addition of thermally modified cowpea protein on sensory acceptability and textural properties of wheat bread and sponge cake

This paper investigates the sensory acceptability and textural properties of leavened wheat bread and sponge cake fortified with cow protein isolates that had been denatured and glycated by thermal treatment. Defatted cowpea flour was prepared from cow pea beans and the protein isolate was prepared (CPI) and thermally denatured (DCPI). To prepare glycated cowpea protein isolate (GCPI) the cowpea flour slurry was heat treated before isolation of the protein. CPI was more susceptible to thermal denaturation than GCPI as determined by turbidity and sulphydryl groups resulting in greater loss of solubility. This is attributed to the higher glycation degree and higher carbohydrate content of GCPI as demonstrated by glycoprotein staining of SDS PAGE gels. Water absorption of bread dough was significantly enhanced by DCPI and to a larger extent GCPI compared to the control, resulting in softer texture. CPI resulted in significantly increased crumb hardness in baked bread than the control whereas DCPI or GCPI resulted in significantly softer crumb. Bread fortified with 4% DCPI or GCPI was similar to control as regards sensory and textural properties whereas 4% CPI was significantly different, limiting its inclusion level to 2%. There was a trend for higher sensory acceptability scores for GCPI containing bread compared DCPI. Whole egg was replaced by 20% by GCPI (3.5%) in sponge cake without affecting the sensory acceptability, whereas CPI and DCPI supplemented cakes were significantly different than the control.

A bread quality study

The objective of this work was to study quality parameters of enriched wheat bread with calcium citrate (Ca3CI2) or lactate (CaLA2) and inulin (In), also to optimize bread formulation. Fermentation time (tf), specific volume (Vs), browning index of crust (BI) and crumb properties (moisture, alveolus, texture) were studied. Generally, tf and Vs decreased with prebiotic increment. Ca3CI2 did not change Vs at equal inulin quantity, whereas with CaLA2 smaller breads were obtained (at 6.5 % In). Moisture of crumbs decreased with an increase in Ca3CI2 (at ≤ 6.5 %); while for CaLA2 was more influenced by the prebiotic. Up to 6.5 % In, the addition of both salts decreased crumb firmness and increased cohesiveness. Using a desirability function, the optimum calcium-prebiotic bread obtained with Ca3CI2 contained 2.40 g/kg Ca and 7.49 % In and with CaLA2 presented 1.33 g/kg Ca and 4.68 % In. Breads of high-quality with higher calcium and prebiotic quantity were able to obtain with Ca3CI2.