Wheat starch structure-function relationship in breadmaking: A review.

Bread dough and bread are dispersed systems consisting of starch polymers that interact with other flour components and added ingredients during processing. In addition to gluten proteins, starch impacts the quality characteristics of the final baked product. Wheat starch consists of amylose and amylopectin organized into alternating semicrystalline and amorphous layers in granules that vary in size and are embedded in the endosperm protein matrix. Investigation of the molecular movement of protons in the dough system provides a comprehensive insight into granular swelling and amylose leaching. Starch interacts with water, proteins, amylase, lipids, yeast, and salt during various stages of breadmaking. As a result, the starch polymers within the produced crumb and crust, together with the rate of retrogradation and staling due to structural reorganization, moisture migration, storage temperature, and relative humidity determines the final product's textural perception. This review aims to provide insight into wheat starch composition and functionality and critically review recently published research results with reference to starch structure-function relationship and factors affecting it during dough formation, fermentation, baking, cooling, and storage of bread.

Optimization of Infrared Heating Conditions for Precooked Cowpea Production Using Response Surface Methodology.

The infrared heating of preconditioned cowpea improves its utilization and potential application in food systems. This study investigated the effect of optimizing preconditioning and infrared heating parameters of temperature and time on cooking characteristics of precooked cowpeas using response surface methodology (RSM). The moisture level (32-57%), infrared heating temperature (114-185 °C), and time of processing the seeds (2-18 min) were optimized using a randomized central composite design to achieve optimal characteristics for bulk density and water absorption. A second-order polynomial regression model was fitted to the obtained data, and the fitted model was used to compute the multi-response optimum processing conditions, which were the moisture of 45%, the heating temperature of 185 °C, and time of 5 min. Precooked cowpea seeds from optimized conditions had a 19% increase in pectin solubility. The total phenolic and total flavonoid contents were significantly reduced through complexation of the seeds' phenolic compounds with other macromolecules but nonetheless exhibited antioxidant properties capable of scavenging free radicals. There was also a significant reduction in phytate and oxalates by 24% and 42%, respectively, which was due to the heat causing the inactivation of these antinutrients. The obtained optimized conditions are adequate in the production of precooked cowpea seeds with improved quality.

Composition, pasting and thermal properties of flour and starch derived from amadumbe with different corm sizes.

Amadumbe, commonly known as taro is a traditional southern African tuber crop. In this study, the effect of corm size: large, medium and small on composition and functional properties of amadumbe flours and starch isolates was determined. With the exception of iron and zinc, the basic chemical composition of amadumbe flours was not affected by differences in corms size. Amadumbe flours contained substantial amount of carbohydrates and limited contents of protein and fat. However, flours derived from large and small corms had iron contents (approx. 3 mg/100 g), which was 3 times that of medium corms. Large corms flour had the highest Zn content (2.6 mg/100 g). Amadumbe corms showed polygonal and small sized (1-5 µm) starch granules containing varying levels of amylose (13-16%). Starch isolates showed reflective peaks at 15° (2θ) and doublet at 17° and 18° typical of A-type starches. Peak viscosity, gelatinisation temperatures and final peak viscosity significantly varied among amadumbe corm types possibly due to variation in amylose contents. Flour mineral content, starch amylose and functionality differ with corm types.

Flour Functionality, Nutritional Composition, and In Vitro Protein Digestibility of Wheat Cookies Enriched with Decolourised Moringa oleifera Leaf Powder.

This study investigated the potential of decolourised Moringa oleifera leaf powder (D-MOLP) in cookies to meet consumer demand for healthier food options, addressing the issue of low acceptability due to its green colour. D-MOLP and its non-decolourised counterpart (ND-MOLP) were incorporated into wheat flour to produce cookies. The results showed that neither decolourisation nor addition level (2.5 or 7.5%) significantly affected water activity or flour functionality, though slight differences in cookie colour were observed. The Moringa-enriched cookies exhibited an improved spread ratio as well as higher protein, phenolic content, antioxidant activity, and in vitro protein digestibility compared to control cookies. The detected phenolic acids included chlorogenic, ferulic, and fumaric acids, with the D-MOLP cookies showing superior nutritional properties, likely due to nutrient concentration and reduced antinutrients. Notably, glutamic acid was the major amino acid in all the cookies, but only lysine significantly increased across the cookie types. This suggests D-MOLP could be a promising alternative for food enrichment. Future research should address the consumer acceptability, volatile components, and shelf-life of D-MOLP-enriched cookies.

A review on structural, digestibility and physicochemical properties of legume starch-lipid complexes.

There is a growing interest in alternative sources of starch for various industrial applications to cater for the increasing demand of starch, avoid the sole reliance on conventional sources such as corn and to prevent shortage of supply. Legume starches with high levels of amylose and high resistant starch contents are suitable alternatives. However, starch must be modified to overcome the shortcomings associated with native starches. The modification of starch with lipids results in the formation of inclusion complexes, called V-amylose complexes with improved physicochemical and functional properties and this category of modified starch is further regarded as clean-label. Clean-label ingredients are consumer and environmentally friendly and do not contain synthetic chemicals that may present food safety concerns. This review documents the current level of research on V-amylose complexes formed using legumes starches and outlines research gaps that could be explored for better utilisation of these legumes in the industry.

A review on the physicochemical properties of starches modified by microwave alone and in combination with other methods.

Native starches are unsuitable for most industrial applications. Therefore, they are modified to improve their application in the industry. Starch may be modified using enzymatic, genetic, chemical, and physical methods. Due to the demand for safe foods by consumers, researchers are focusing on the use of cheap, safe and environmentally friendly methods such as the use of physical means for starch modification. Microwave heating of starch is a promising physical method for starch modification due to its advantages such as homogeneous operation throughout the whole sample volume, shorter processing time, greater penetration depth and better product quality. More recently, the use of synergistic methods for starch modification is being encouraged because they confer better functionality on starch than single methods. This review summarizes the present knowledge on the structure and physicochemical properties of starches from different botanical origins modified using microwave heating alone and in combination with other starch modification methods.

Infrared heating under optimized conditions enhanced the pasting and swelling behaviour of cowpea starch.

Native starches are not suitable for industrial use and must be modified for improved functionality. In this study, the effect of moisture preconditioning and infrared heating time on physicochemical properties of cowpea starch was investigated using a two-factor central composite rotatable design. Factors (moisture levels:10-40 g/100 g starch and infrared heating time:10-60 min) with their corresponding α mid-point values resulted in 13 experimental runs. Selected functional and pasting properties were determined as response variables. Starch samples produced under optimized conditions were compared with corn starch and their physicochemical properties determined. Except for pasting temperature, cowpea starch prepared using the optimal conditions (moisture: 46.21 g/100 g starch, dry basis and heating time of 32.88 min) had higher functional and pasting properties compared with the native cowpea starch. Infrared heating significantly reduced the gelatinization temperatures of cowpea starch but did not significantly change that of the corn starch. The crystallinity and double-helical order structure of moisture conditioned cowpea starch also reduced after modification. Cowpea starch showed a bigger granule size, higher swelling power but lower water absorption capacities and pasting properties compared with the control. The infrared heating process is a novel and promising modification method for improving the swelling properties of starch.

The prospects of African yam bean: past and future importance.

African yam bean (AYB) is an underutilised legume indigenous to West and East Africa with nutritional content comparable to other commonly consumed legumes. The nutrient density of the crop makes it a viable food crop for ameliorating the challenges of malnutrition faced in many developing countries, via direct consumption or fortification and enrichment of less nutritious staples. This review summarises the current body of knowledge on the use of African yam bean as a viable enrichment and fortification crop. Proximate composition and nutritional quality of foods (breakfast diets, traditional foods, snacks and instant noodles) fortified, enriched and complemented with AYB were discussed. The phytochemical and antioxidant potential of the crop were also discussed. Future studies should focus more on awareness towards the deliberate commercialisation of the crop and elevation of its status into a widely - consumed food in all households across developing countries. Adequate experimental design for optimum quantity to be used in the enrichment and fortification of many staples to improve their acceptance among consumers should be put in place. Phytochemical extracts of the bean are also proposed for use in the development of functional foods to mitigate against many lifestyle diseases.

Quality attributes of breads from high-quality cassava flour improved with wet gluten.

This study investigated the physical, chemical, and sensory attributes of breads produced from preheated high-quality cassava flour (PCF) and its composite with wheat flour (CWF). Wet gluten was added to the PCF and CWF for production of bread, while bread from wheat served as the control. Flour functionality was determined prior to bread production. The moisture contents of the flour samples were in the range of 12.80 to 14.21%, and PCF exhibited water absorption capacity (1.12 mL/g) comparable to that of wheat flour (WF) (1.10 mL/g). There were significant (P < 0.05) differences in color characteristics, except in L* values and breads produced from WF and CWF were similar in specific volume (3.85 to 4.21 mL/g) and firmness (2.04 to 2.64 N). Breads from WF and CWF exhibited similar crumb microstructure, though gas bubbles in the sample from PCF appeared less developed. Wheat bread had significantly (P < 0.05) higher calorie, crude protein and crude fat, but lower crude fiber, ash, and carbohydrate compared to other bread samples. Sensory evaluation showed that bread from PCF was not significantly different from 100% wheat bread in crust color, texture, and overall acceptability but was impaired in flavor. The study revealed the feasibility of bread baking from preheated cassava flour with added gluten extract. The bread produced had some quality attributes comparable to that of wheat bread. PRACTICAL APPLICATION: Bread from wheat-cassava composite flour with added gluten was similar to wheat bread in specific volume and firmness while sample from cassava flour with added gluten compared favorably well with wheat bread in crust color, texture, and overall acceptability. Findings from the study present wheat gluten extract as a viable component to be used in nonwheat flours for bread making. This could be a basis to further add value to the gluten churned out as a by-product in the wheat starch industry.

Impact of steam-heat-moisture treatment on structural and functional properties of cassava flour and starch.

In this study, moisture, steam-temperature and time conditions were optimised in relation to functional properties of cassava flour and starch. The optimal conditions for cassava flour were 15% moisture, 120 °C and 1 bar for 10 min and for cassava starch were 19% moisture, 120 °C and 1 bar for 20 min. Structural, physicochemical, viscoelastic and thermal characteristics of cassava flour and starch upon the optimal steam-heat-moisture treatments were examined Volume-based diameter (D(4.3)) of cassava flour granules reduced (107.87 to 42.94 µm) and cassava starch granules increased (17.67 to 50.88 µm) when subjected to optimal steam-heat-moisture treatments. The optimal steam-heat-moisture treatments had no effect on the crystal patterns of cassava flour and starch (A-type), nonetheless, relative crystallinity of cassava flour was increased (34 to 59%) and cassava starch was decreased (32 to 27%). Increments in swelling power (17.24 to 19.07 g/g) and peak viscosity (6377 and 7330 cP) and, reductions in solubility and loss factor (tanδ) were ensued by the optimal steam-heat-moisture treatment of cassava starch. Both optimal steam-heat-moisture treatments of cassava flour and starch had increased thermal stability but reduced breakdown viscosity, setback viscosity (528 to 230 cP and 1259 to 938 cP, respectively) and gelatinisation enthalpy.

Structural and functional characteristics of optimised dry-heat-moisture treated cassava flour and starch.

The flexibility of hydrothermal conditions gives rise to an array of effects on the properties of starch-containing systems. This study examined and optimised moisture, temperature and time conditions with regards to functional properties of cassava flour and starch. The derived optimal conditions for cassava flour were 25%, 90 °C and 45 min, respectively, while cassava starch were 27%, 120 °C and 21 min, respectively. Consequently, effect of the optimal conditions on structural, physicochemical, rheological and melting characteristics of cassava flour and starch were studied. Optimal heat-moisture treatments changed both morphology and size distribution of cassava flour and starch granules. Relative crystallinity of cassava flour increased (34 to 40%) and cassava starch decreased (32% to 23%) following optimal-heat-moisture treatment. Both cassava flour and starch upon optimal dry-heat-moisture treatment exhibited enhanced; swelling power (15.57 to 21.62 g/g and 17.24 to 19.64 g/g, respectively), peak viscosity (3555 to 5493 cP and 6377 to 8701 cP, respectively), elasticity (tan δ) (0.31 to 0.24 and 0.58 to 0.47, respectively) and melting onset temperature to conclusion temperature range (14.66 to 15.75 °C and 23.26 to 30.69 °C, respectively). This research presents hydrothermal conditions that can effectively be applied in industry to improve the bakery potentials of cassava flour and starch.

Physicochemical and Mechanical Properties of Bambara Groundnut Starch Films Modified with Stearic Acid.

The physicochemical and mechanical properties of biofilm prepared from bambara starch modified with varying concentrations of stearic acid (0%, 2.5%, 3.5%, 5%, 7%, and 10%) were studied. By scanning electron microscopy, bambara starch films modified with stearic acid (≥3.5%) showed a progressively rough surface compared to those with 2.5% stearic acid and the control. Fourier transform infrared spectroscopy spectra revealed a peak shift of approximately 31 cm-1 , suggesting the promotion of hydrogen bond formation between hydroxyl groups of starch and stearic acid. The addition of 2.5% stearic acid to bambara starch film reduced water vapor permeability by approximately 17%. Bambara starch films modified with higher concentration of stearic acid were more opaque and showed significantly high melting temperatures. However, mechanical properties of starch films were generally negatively affected by stearic acid. Bambara starch film may be modified with 2.5% stearic acid for improved water vapor permeability and thermal stability with minimal effect on tensile strength.

Novel Synthesis of Phytosterol Ester from Soybean Sterol and Acetic Anhydride.

Phytosterols are important bioactive compounds which have several health benefits including reduction of serum cholesterol and preventing cardiovascular diseases. The most widely used method in the synthesis of its ester analogous form is the use of catalysts and solvents. These methods have been found to present some safety and health concern. In this paper, an alternative method of synthesizing phytosterol ester from soybean sterol and acetic anhydride was investigated. Process parameters such as mole ratio, temperature and time were optimized. The structure and physicochemical properties of phytosterol acetic ester were analyzed. By the use of gas chromatography, the mole ratio of soybean sterol and acetic anhydride needed for optimum esterification rate of 99.4% was 1:1 at 135 °C for 1.5 h. FTIR spectra confirmed the formation of phytosterol ester with strong absorption peaks at 1732 and 1250 cm(-1) , which corresponds to the stretching vibration of C=O and C-O-C, respectively. These peaks could be attributed to the formation of ester links which resulted from the reaction between the hydroxyl group of soybean sterol and the carbonyl group of acetic anhydride. This paper provides a better alternative to the synthesis of phytosterol ester without catalyst and solvent residues, which may have potential application in the food, health-care food, and pharmaceutical industries.

Physicochemical properties of starches with variable amylose contents extracted from bambara groundnut genotypes.

The physicochemical properties of starches extracted from five bambara genotypes were investigated. Bambara starch granules were predominantly oval shaped with a smooth surface and an average size of 26±0.2µm. The amylose contents (20-35%) varied significantly among genotypes. X-ray diffraction revealed the C-type pattern for all starches with relative crystallinity range: 29-35%. FTIR spectra of bambara starches showed variable peak intensities at 2931, 1655 and 860cm(-1), which corresponds to CH stretching, H2O bending vibrations and CO stretching, respectively. Bambara genotype with the highest amylose content showed the lowest intensity at wavenumber 2931cm(-1). With the exception of oil absorption which was similar, swelling power, water absorption and paste clarity of starches were significantly different among genotypes. Genotype with high amylose content showed restricted swelling, low paste clarity and great ability to absorb water. All bambara starches displayed a shear thinning behaviour (n<1).