Physicochemical and sensory attributes of gluten-free sourdough breads produced from underutilised African cereal flours and flour blends

To seek potential alternative(s) for imported wheat in the African baking industry, the physicochemical parameters and sensory attributes of sourdough breads developed from locally sourced underutilised cereals and their blends were assessed. Processed sorghum (Sorghum bicolour), finger millet (Eleusine coracana) and pearl millet (Pennisetum glaucum) and their composites (50:50) were used to produce sourdough. Sourdough and flour-sourdough blends (30% sourdough) were used in making gluten-free breads. The protein content of the breads ranged from 16.29% to 39.26%, whereas the fat, crude fibre, ash and carbohydrate contents fell between 14.02–18.80%, 0.55–1.22%, 1.90–3.32% and 42.16–65.61%, respectively. The calculated energy value of the gluten-free breads (405.99–446.39 Kcal per 100 g) exceeded that of wheat bread (396.43 Kcal per 100 g), while the specific loaf volume varied from 1.46 to 1.80 cm³ g⁻¹. Although the produced gluten-free breads have improved nutritional content compared to conventional wheat bread, they were at best moderately liked. This is perhaps due to the non-cohesive nature of the crumbs and psychological preference for known products. Further research targeted at improving the organoleptic properties of these sourdough breads is recommended.     

A study of gluten extractability from doughs made from fresh and stored wheat flours

In contrast to the increase in protein extractability which normally occurs in making a dough from a flour, on overmixing dough from a freshly milled flour of good bread-baking quality, a progressive reduction occurs in the amount of acetic acid soluble proteins whereas the protein solubility shows little change in equivalent doughs made from similar flours stored for several years. Addition of artificially aged flour lipid, addition of oleic acid or defatting all tend to make the fresh flour imitate the behaviour of stored flour. Addition of diacetyl tartaric acid ester of mixed monoglyceride (which improves baking properties) to a stored flour makes the protein extractability move towards that of a fresh flour. It is suggested that in making dough from a fresh flour, there is a progressive binding of fresh flour lipid by the high molecular weight flour protein, which subsequently causes insolubility of this protein and that this binding like other lipid-protein interactions is a major factor influencing flour baking performance.     

Effects of oxidase and protease treatments on the breadmaking functionality of a range of gluten-free flours

In this study, the application of glucose oxidase and protease commercial preparations was investigated in order to evaluate their impact on the breadmaking performance of four different gluten-free flours (buckwheat, corn, sorghum and teff). Bread formulas were developed without addition of hydrocolloids in order to avoid synergistic effects. Glucose oxidase improved corn (CR) and sorghum (SG) bread quality by increasing specific volume (P < 0.05) and reducing collapsing at the top. The improvements could be related to protein polymerization which resulted in enhanced continuity of the protein phase and elastic-like behavior of CR and SG batters. No significant effects were detected on buckwheat (BW) and teff breads. On the other hand, protease treatment had detrimental effects on the textural quality of BW and SG breads. The effects were related to protein degradation resulting in increased liquid-like behaviour of BW and SG batters. Overall, the results of this study suggest that protein polymerisation can improve the breadmaking performance of gluten-free flours by enhancing elastic-like behaviour of batters. However, the protein source is a key element determining the impact of the enzymes. In the absence of hydrocolloids, protein structures are important to ensure the textural quality of these types of breads.     

Quantitative assessment of protein fractions of Chinese wheat flours and their contribution to white salted noodle quality

Protein quantity and quality play a significant contribution to white salted noodle processing. The objective of this study was to determine the contribution of different protein fractions to 25 Chinese varieties on wheat based noodle quality. The results showed: the average ratio of monomeric protein, soluble glutenin and insoluble glutenin in Chinese Huanghuai winter wheat was 3.7:1.0:1.8. Compared with Canadian wheat varieties, the ratio was 4.4:1.0:2.0. The monomeric protein and insoluble glutenin were lower in the Chinese varieties, the soluble glutenin content was higher; while the dough character was lower than Canadian hard wheat, but most Chinese wheat can make good quality noodles. This may be the defining difference between noodle wheat and bread wheat. The monomeric protein content was significant positive correlated with fresh noodle maximum resistance, and high significant positive with extension distance and area. The soluble and insoluble glutenin were mainly responsible in fresh noodle maximum resistance, extension distance and using a texture analyzer, but were high negative correlated with fresh noodle sheet length (Table 2). For cooked noodles, the soluble glutenin content demonstrated a high significant positive relationship to cutting firmness, and a significant negative correlation to cooking loss. The insoluble glutenin content was high significant positive correlated with cooked noodle thickness, hardness and cutting firmness (Table 3). The results suggested that the monomeric protein is less important than that of the glutenin for fresh noodle resistance. The soluble glutenin content is the most important property for noodle wheat, and soluble glutenin content can be used in the early generations to identity Chinese noodle wheat.     

Physical properties and sensory acceptability of cookies made from chickpea addition to white wheat or whole wheat flour compared to gluten‐free amaranth or buckwheat flour

The effects of chickpea addition (0–100%) on the physical properties and sensory attributes of cookies based on white or whole wheat compared to gluten‐free amaranth or buckwheat flour were studied. The physical properties determined were spread factor, colour and hardness. Sensory evaluation was conducted for colour, taste, texture and overall impression. Chickpea addition decreased the lightness in white wheat cookies while increasing it in whole wheat and amaranth cookies and it significantly increased yellowness in all cookies. Spread factor of the gluten‐free cookies was reduced by chickpea addition and hardness was increased in white wheat and buckwheat cookies, and decreased in whole wheat and amaranth cookies. Sensory evaluation demonstrated that chickpea addition increased the acceptability of all cookies, in particular of the gluten‐free cookies. Optimal levels of chickpea addition were 20–40% in wheat cookies and 60–80% for amaranth and buckwheat cookies.     

Investigation of molecular weight distribution of LBG galactomannan for flours prepared from individual seeds, mixtures, and commercial samples

The molecular weight distribution has been determined for the galactomannan solubilized from three types of locust bean gum (LBG) flours: single carob seeds, mixtures, and a range of commercial products. To prepare crude endosperm flours from carob seeds with minimal galactomannan degradation, a new extraction and milling method was developed. The method consists of applying a brief thermal shock to the seeds, followed by an extended 3-day swelling period, and manual separation of endosperms; particle size reduction to a flour is accomplished on hydrated endosperms using a centrifugal mill. This method was optimized so that redissolved LBG flours produced solutions with the highest possible viscosity and the least amount of galactomannan degradation as determined by SEC. For the three samples types, the molecular weight distribution, w(M), was found to be unimodal, appearing as a sharply defined main peak (M_p≈1.1×10⁶ g/mol) with a small high molecular weight tail (up to 2.0×10⁶ g/mol) and broad low molecular weight tail (down to 0.01×10⁶ g/mol); polydispersities (M_w/M_n) were estimated to be 1.5–1.8. Variations in M_w and [η] for galactomannans extracted from individual seeds originating from the same carob tree were minimal and nearly indistinguishable from a bulk mixture (6 seeds, M_w=0.96–1.1×10⁶ g/mol, [η]=14.2–15.1 dl/g). There was a higher variability in these molecular parameters for galactomannans solubilized from commercial LBG flours, which generally exhibited lower M_w and [η], broader distributions, and reduced solubilities (M_w=0.86–1.0×10⁶ g/mol, [η]=12.4–13.6 dl/g). These side-effects were attributed to damage caused by industrial scale seed processing. The near constancy of M_p for the three sample types suggests that the average molecular size of LBG galactomannan varies only slightly due to natural or biological causes.     

Dehulling characteristics,sensory and functional properties of flours from selected cowpea varieties

BACKGROUND: The knowledge of dehulling characteristics is very important in the selection of cowpeas for flour production. In this study the sensory and functional properties of cowpea flour as influenced by dehulling method (wet and dry/mechanical dehulling) and cowpea variety (white, maroon and mottled) were investigated. RESULTS: White cowpea showed a significantly different (P < 0.05) and higher dehulling rate (DR > 97%) for all dehulling methods. Maroon and mottled cowpeas were poorly dehulled (DR < 10%) when using the wet method (WD). Dry dehulling (DD) was effective on all three varieties (DR > 94%). The highest yield of flour was observed with white cowpea (80% for DD and 96% for WD). The beany odour intensity of flours was dependent on the method of dehulling used. Flour functionality was more significantly influenced by cowpea variety than by dehulling method. CONCLUSION: Dry dehulling could be recommended for cowpea flour production, as this method was found to be more effective on the selected cowpea varieties. Owing to the observed variation in flour functionality among cowpea varieties, the choice of a particular variety for flour production will depend on the intended use of the flour. Copyright © 2009 Society of Chemical Industry     

Consumer orientation of product developers and their product perception compared to that of consumers

This research concludes that although product developers (58, response rate 35%) and consumers (344, response rate 57%) perceive health and its relation to product characteristics in the same way, the perception of product developers is more extreme. Furthermore, factor analysis reveals four orientations of product developers: technology and cost orientation, which are related to the use of more traditional work methods, and customer and consumer orientation, which are related to the use of more recent and interactive work methods. These four orientations are related to different opinions about factors influencing failure of products, use of models and cooperation.     

Incorporation of germinated mung bean flour with rice flour to enhance physical,nutritional and sensory quality of gluten-free cookies

Quality of the cookies substituted with germinated mung bean flour (GMF) to rice flour (RF) to produce gluten-free cookies were investigated in this study. The GMF was used to formulate with the RF to obtain the composite flours with different total protein contents of 6, 9, 12, 15, 18 and 21 (%, d.b). The increase in the substituted amounts of GMF contributed to the lower baking loss, diameter and spread ratio, but the higher thickness and hardness of the cookies as compared to the RF-based cookie. The cookies with more GMF substitution expressed lower lightness (L*) values, but higher redness (a*) and yellowness (b*) values than the others. The cookies substituted with 60% of the GMF (60-GMFC) exhibited similar baking loss, thickness, diameter, spread ratio and lightness values to the wheat flour (WF)-based cookies. The total amounts of essential amino acids and the sum of histidine, lysine and methionine of the composite flour-based cookies were 3.90% and 1.64%, significantly higher than those of the RF-based cookie (1.93% and 0.66%, respectively) or the WF-based cookie (1.70% and 0.58%, respectively). As a result, healthy gluten-free cookies could be prepared using the RF with the substitution of the germinated mung bean flour.     

Effects of red rice flour addition on the rheological,textural, sensory and bioactive properties of wheat flour-based pan breads

Red rice, rich in fibre and phenolic contents, is one of the underutilised grains. Therefore, the present study developed the wheat/red rice flour (RRF) composites followed by its utilisation in pan breads. It led to an increase in ash and fibre contents of resultant flour combinations, but gluten network became weaker. The values for water absorption were unaffected with RRF replacements ≤15% of wheat flour. Moreover, the proximate estimates of RRF added breads demonstrated increased moisture and fibre contents. Substituted bread combinations were harder with increased gumminess and springiness values; however, cohesion decreased. The per cent change in cohesion and hardness of individual breads upon storage was lesser in composites compared to control suggesting decline in staling phenomenon. Nutritional assessment of both RRF containing flour and breads showed higher total phenolic content and DPPH radical scavenging activity compared to their respective controls. Composite breads also demonstrated reduced glycaemic index suggesting its importance for diabetic patients.     

Heat damage of water biscuits from einkorn,durum and bread wheat flours

To limit heat damage and improve the nutritional properties of bakery products, furosine, glucosylisomaltol, hydroxymethylfurfural, furfural, sugars, α-amylase, β-amylase and colour were assessed during the production of water biscuits from three einkorn, three bread and one durum wheat flours. Heat damage indices, colour and a_w development during baking (from 25 to 75 min duration) of water biscuits from one bread wheat were also studied.