Optimization of Gluten-Free Bread Prepared from Cornstarch, Rice Flour, and Cassava Starch

ABSTRACT: The proportions of cornstarch, cassava starch, and rice flour were optimized for production of gluten-free bread (with 0% and 0.5% soy flour) to maximize specific volume (Y₁,Y₁'), crumb-grain score (Y₂,Y₂'), and bread score (Y₃,Y₃'). A central composite design involving cornstarch/cassava starch ratio (X₁) and rice flour/cassava starch ratio (X₂) was used, and 2nd-order models for Y₁ and Y₁' were employed to generate response surfaces. The maxima of response surfaces for crumb-grain score and bread score indicate that optimal gluten-free bread can be prepared from 74.2% cornstarch, 17.2% rice flour, and 8.6% cassava starch. Addition of soy flour at the 0.5% level also improved bread texture.     

Screening of Starch Quality Traits in Cassava (Manihot esculenta Crantz)

Cassava (Manihot esculenta Crantz) is one of the most important sources of starch in the tropics. There is limited and contradictory information regarding cassava starch characteristics. The International Center for Tropical Agriculture (CIAT) holds in trust FAO's cassava germplasm collection. Starches from 3272 landraces (including 12 wild relatives) and 772 improved clones were extracted and analyzed over a period of several years. In most cases only one starch sample per genotype was analyzed. Average cyanogenic potential was 327 ppm but considerably higher in the landraces (340 ppm) than in improved clones (267 ppm). Average total and reducing sugars were slightly higher in improved clones (4.06 and 1.56%, respectively) than in landraces (3.68 and 1.25%, respectively). Amylose content was similar in both types of germplasm with an average of 20.7%. Average pasting temperature was 65.3°C. Maximum viscosity was 777.5 mPa s, breakdown was 298.1 mPa s, consistency was 155.8 mPa s and setback was ‐144.5 mPa s. The large sample of starches analyzed provides very robust information regarding the actual characteristics of cassava starch.     

Sensory characteristics and iron dialyzability of gluten-free bread fortified with iron

The objectives of the present study were (a) to produce gluten-free bread, fortified with iron (GFB-Fe), using selected iron compounds (ferric pyrophosphate, ferric pyrophosphate with emulsifiers, NaFeEDTA, electrolytic iron, ferrous gluconate, ferrous lactate and ferrous sulphate) (b) to test sensory characteristics of the GFB-Fe (feel-mouth texture, crumb colour, aroma and taste) (c) to compare iron dialyzability of various iron compounds in GFB-Fe. The most acceptable products were those fortified with ferric pyrophosphate with emulsifiers and ferric pyrophosphate. Ferrous dialyzable iron (ferrous iron with molecular weight lower than 8000 Da, an index for prediction of iron bioavailability) was measured under simulated gastrointestinal conditions. Ferrous dialyzable iron in GFB-Fe fortified with ferric pyrophosphate with emulsifiers, NaFeEDTA, ferrous bis-glycinate, ferrous gluconate or ferrous sulphate was higher than that in GFB-Fe fortified with electrolytic iron, ferrous lactate or ferric pyrophosphate (P < 0.05). These results are promising for the development of GFB-Fe products in the future.     

Synthesis and Characterization of low DS Succinate Derivatives of Cassava (Manihot esculenta Crantz) Starch

Succinylation of cassava starch was carried out in aqueous medium to prepare derivatives with low degree of substitution (DS) and the physicochemical properties of the products were determined. A response surface design was used for the experiment with three levels of each of the three variables viz., concentration of succinic anhydride, reaction time and pH of the reaction medium. The reaction was followed in terms of the DS of the products and reaction efficiency (RE). The degree of substitution of the derivatives varied from 0.001 to 0.022 and reaction efficiency from 2.2 to 46.8%. The DS and RE showed an adequate fit to a second order polynomial model of the variables used. Succinylation brought about increase in the swelling volume, peak viscosity and paste clarity of the starch. However, the pasting temperature and solubility did not show any significant change. The in‐vitro α‐amylase digestibility of the succinylated derivatives decreased in comparison to that of native starch and this decrease correlated with a corresponding increase in DS.     

Texture and Microstructure of Cassava (Manihot esculenta Crantz) Flour Extrudate

Cassava flour (Manihot esculenta Crantz) was texturized by single-screw extrusion processing. Relationships between texture and micro-structure as a function of extrusion variables were examined. The effect of feed moisture or screw speed was significant (P < 0.01) on all textural parameters except springiness and energy first bite. Hardness, gumminess (P < 0.05) fracturability and cohesiveness (P < 0.01) decreased with increasing temperature. Hardness, fracturability and firmness were lowest at screw speed 520 rpm with feed rate 300g/min, 120–125°C and 11% feed moisture. Scanning electron micrographs showed structural change from a coarse cell mass at high feed moisture to a porous, thin-walled structure with decreased feed moisture.     

Microwave‐Assisted Synthesis and Characterization of Succinate Derivatives of Cassava (Manihot esculenta Crantz) Starch

The use of microwave heating to prepare very rapidly cassava starch succinates with high viscosity is described. A response surface design was used for the experiment and different factors affecting the succinylation of cassava starch, including concentration of succinic anhydride, reaction time, temperature and moisture content of the medium were investigated. The degrees of substitution of the modified starches increased with an increase in reaction time and were in the range 0.007 – 0.051. The products exhibited higher viscosity, lower pasting temperature, enhanced water binding capacity and reduced swelling and paste clarity than unmodified cassava starch. The results of this study indicated that succinylation of starch can be achieved in shorter reaction times, which offers a benefit to laboratories and industries involved in developing newer and more versatile uses for cassava starch.     

Physicochemical Properties and Starch Granular Characteristics of Flour from Various Manihot Esculenta (Cassava) Genotypes

ABSTRACT: Flour and starch were produced from 11 cassava genotypes. Starch and total dietary fiber contents were determined using a single-enzyme gravimetric procedure and high-performance anion exchange chromatography, pasting profiles by rotary viscometry, water holding capacity gravimetrically, and granular characteristics by scanning electron microscopy. Starch and total dietary fiber contents varied among genotypes. Flour peak viscosities, setback, and final viscosities differed significantly. Flour water holding capacity correlated with flour peak viscosity (r = 0.7). Starch granules ranged from 9 to 20 μm. Predominant granule shapes were oval, rounded, and truncated. The results provide insights into cassava genotype characteristics, and functionality of cassava starch and flour.     

Effect of Cross‐linking with Epichlorohydrin on the Properties of Cassava (Manihot esculenta Crantz) Starch

Cassava starch was cross‐linked with epichlorohydrin (EPI) at 45°C for 2 h in three different media which include water, water in the presence of a phase transfer catalyst (PTC) and N,N‐dimethylformamide (DMF). The products were characterized by determining their physicochemical, thermal and retrogradation properties. In aqueous medium, the use of a PTC, tetrabutylammonium bromide (TBAB) produced derivatives with higher degree of cross‐linking than those prepared without the use of the catalyst. The degree of cross‐linking was found to be higher using the same concentration of EPI when the reaction was carried out in DMF. At low levels of cross‐linking, the peak viscosity of the cross‐linked starches increased in comparison to that of the native starch. With increasing degree of cross‐linking, the peak viscosity showed a significant reduction. The swelling volume, solubility and light transmittance of the starch pastes were lower for the modified starches. The cross‐linked starches showed slightly reduced values for the gelatinization temperatures, T_onset, T_peak and T_end. The enthalpy of gelatinization of the modified starches increased with increase in the degree of cross‐linking. The modified starches exhibited higher water‐binding capacities (WBC) than the native starch; but with increase in the degree of cross‐linking, there was a gradual decrease in WBC. The in vitro alpha amylase digestibility of the modified starches decreased gradually with increase in the level of cross‐linking.     

Macroscopic and Sensory Evaluation of Bread Supplemented with Sweet-potato Flour

ABSTRACT: The macroscopic and sensory properties of breads supplemented with 50%, 55%, 60%, and 65% sweet-potato flour were evaluated. Moisture contents of the breads fluctuated during storage. Protein value was highest for the bread supplemented with 50% sweet-potato flour. Carbohydrate contents ranged from 18.2% to 24.4%. β-caro-tene contents and loaf volumes were highest in the breads supplemented with 65% and 50% sweet-potato flour, respectively. The breads were similarly firm, with comparable vitamin C contents at the end of storage. The bread with 65% sweet-potato flour had the most intense yellow-orange color. Twelve perceived sensory attributes, which could be used to differentiate the appearance, texture, and flavor of sweet-potato breads, were generated.     

Soybean Flour/Oil and Wheat Bran Effects on Characteristics of Cassava (Manihot esculenta Crantz) Flour Extrudate

Adding soybean flour, soybean oil and wheat bran to cassava flour increased the percentage of crude protein/fat and crude fiber respectively in the blends. Crude protein or extrudate correlated negatively (P<0.01) with expansion, water solubility or total reducing sugars and positively (P<0.01) with bulk density, and water absorption. Crude fiber of extrudate correlated negatively (P<0.01) with expansion, bulk density and total reducing sugars. At 4% soybean oil addition, extrudate expansion and WSI were highest, while bulk density and WAI were lowest. Extrudates became more yellow in color on addition of soybean flour.     

Cassava (Manihot esculenta Crantz) and Yam (Dioscorea spp.) Crops and Their Derived Foodstuffs: Safety,Security and Nutritional Value

Cassava (Manihot esculenta Crantz) and yam (Dioscorea spp.) are tropical crops consumed by ca. 2 billion people and represent the main source of carbohydrate and energy for the approximately 700 million people living in the tropical and sub-tropical areas. They are a guarantee of food security for developing countries. The production of these crops and the transformation into food-derived commodities is increasing, it represents a profitable business and farmers generate substantial income from their market. However, there are some important concerns related to the food safety and food security. The high post-harvest losses, mainly for yam, the contamination by endogenous toxic compounds, mainly for cassava, and the contamination by external agents (such as micotoxins, pesticides, and heavy metal) represent a depletion of economic value and income. The loss in the raw crops or the impossibility to market the derived foodstuffs, due to incompliance with food regulations, can seriously limit all yam tubers and the cassava roots processors, from farmers to household, from small-medium to large enterprises. One of the greatest challenges to overcome those concerns is the transformation of traditional or indigenous processing methods into modern industrial operations, from the crop storage to the adequate package of each derived foodstuff.     

Physical,Sensorial and Chemical Characteristics of Simulated Chips of Cassava (Manihot Esculenta Crantz): Rice (Oryza Sativa L.) Mix

Cassava-rice ratio and cooking time-temperature combinations in baked and fried simulated chips making enriched with carrot, celery, curry leaves and skim milk were studied using completely randomized design. Research found that interaction between mix formula and cooking methods was significantly affected (p<0.05) the physical, sensorial and chemical characteristic of the simulated chips. The best baked simulated cassava-rice simulated chips was resulted from 80:20 ratio, baked at 140 °C for 14 minutes, and the fried cassava-rice simulated chips with 60:40 ratio fried at 150 °C for 2.5 minutes. The fried chips have finer microstructure and more preferable than the baked one. However, both best chips were potential to be further developed.     

Processing Factors Affecting the Yield and Physicochemical Properties of Starch from Cassava Chips and Flour

Three processing factors, namely, raw materials type (RMT) (i.e. chips and flour) and raw material drying mode (RDM) (i.e. sun‐ and oven‐drying at 55 °C) were related to the yield and some physicochemical properties of starch in a 2³ factorial experiment. The quality characteristics investigated were: moisture content, pH, crude fiber content, peak viscosity and pasting temperature. Starch yields from oven‐dried chips and flour were significantly higher (at 5%) than from sun‐dried materials. The optimal yield of 55.9 g (per 70 g of dried product or 79.9%) was obtained from oven‐dried starch extracted from oven‐dried flour. The peak viscosities (PV) of starches extracted from flour and chips were similar while the observed pasting temperatures of flour‐extracted starches were not significantly different from those derived from chips.     

豆渣粉对小麦面团、馒头质构特性及馒头品质的影响

为了解豆渣粉对面团及馒头特性的影响,每100 g面粉中分别添加0、5、10、15、20 g豆渣粉,利用质构仪测定分析豆渣粉添加量对面团及馒头质构特性的影响,然后对馒头感官品质进行评价。结果表明：随着豆渣粉添加量的增加,面团及馒头的硬度、胶黏性、咀嚼性及黏附性显著增加（P＜0.05）;面团的内聚性、弹性变化不显著;馒头的内聚性、弹性呈显著降低趋势;馒头的感官品质变差。因此,豆渣粉的添加,改变了面团和馒头的质构特性及馒头的感官品质。     

Nutritional,Functional and Physical Properties of Extrudates from Blends of Cassava Flour with Cereal and Legume Flours

Low protein and poor functionality limit the use of cassava flour in snack foods, which were modified using blends with cereal and/or legume flours. Native, malted (using alpha-amylase) as well as malted and pre-gelatinized was blended with cereal (finger millet and whole wheat flours) and/or legume (chick pea flour). Extrudates were prepared at a screw speed of 100 rpm and die temperature of 180 °C. Malted flour based extrudates had lower starch content than native flour. Gram malted cassava based blends gave products with the highest protein. In vitro starch digestibility was the highest for pre-gelatinized flour based mixes. Extrudates with low fat and energy have scope as low calorie snacks for obese and diabetic people.     

Moisture stress during growth affects the breadmaking and gelatinisation properties of cassava (Manihot esculenta Crantz) flour

Breadmaking quality (judged by the regularity of the crumb) of cassava (in cassava flour/defatted soy flour/glyceryl monostearate recipes (80/20/3, w/w), Cereal Chem 68 323–327 1991) is related to crop age and the season of planting and harvesting. When taking the data sets of the dry season (J Sci Food Agric 66, 193–202 1994) and rainy season (ibid 68 167–174 1995) together, the following additional interpretation results: breadmaking quality of cassava is positively related to flour from roots with unrestricted growth, and therefore influenced by rainfall distribution, time of planting and harvesting. Variability in baking performance of cassava flour samples is related to the length and severity of the dry season, the growth behaviour of the genotype and the crop age. The highest flour breadmaking quality is obtained after 6 months of unrestricted growth of cassava irrespective of the planting season. © 1998 SCI.     

Production and characterization of oxidized cassava starch (Manihot esculenta Crantz) biodegradable films

Plastic is one of the most common pollutants in the environment. Therefore, the number of studies on the use of biodegradable packaging is increasing. Starch is the primary material used in the production of biodegradable plastics due to its natural abundance and high biodegradability. Yet, the strong hydrophilic character of starch presents a challenge. Therefore, the modification of its structure through oxidation may yield interesting results as the viscosity reduction. The objectives of this work were to obtain cassava (Manihot esculenta Crantz) starch oxidized with 0.8 and 2.0% active chlorine, to develop biodegradable films and characterize their mechanical properties, solubility in water, permeability to water vapor, degree of swelling, and sorption isotherms. Biodegradable films were produced with starch concentrations of 2, 3, 4, and 5% w/w and 25% glycerol (g/100 g starch) added as a plasticizer. Images of the films were obtained with an atomic force microscope and allow to observe a smooth surface and the absence of starch granules in the film produced with oxidized starches. The tensile strength of the biodegradable film produced with oxidized starch (0.8% active chlorine) was 80 MPa. The value of permeability to water vapor was 1.613 × 10⁻⁹ kg/day/m/Pa, and the average solubility was 41%. The sorption isotherms showed that biodegradable films made with oxidized starches cannot be used in environments with relative humidity below 35% or above 90%.