Optimization of Baking of Rice Cakes in Infrared–Microwave Combination Oven by Response Surface Methodology

In this study, response surface methodology was used to design gluten-free cakes made from rice flour to be baked in infrared-microwave combination oven. Two types of cake formulations containing different types of gums were used in the experiments, which were xanthan gum and xanthan–guar gum blend. The independent variables were emulsifier content (0, 3, and 6% of flour weight), upper halogen lamp power (50, 60, and 70%), and baking time (7, 7.5, and 8 min). Specific volume, surface color change, firmness and weight loss of the cakes were determined for optimization. Cakes formulated with xanthan gum had better quality characteristics than cakes containing xanthan–guar gum blend. Cakes formulated with xanthan gum and 5.28% emulsifier and baked using 60% halogen lamp power for 7 min had the most acceptable quality.     

Utilization of chestnut flour in gluten-free bread formulations

In this study, gluten-free bread formulations using chestnut and rice flours at different ratios (0/100, 10/90, 20/80, 30/70, 40/60, 50/50 and 100/0) were tested. In addition, the influence of hydrocolloid blend (xanthan-locustbean gum (LBG), xanthan-guar gum blend) and emulsifier DATEM on the rheological properties of dough formulations and quality parameters of breads were also investigated for the samples having chestnut/rice flour ratio of 10/90, 20/80, 30/70 and 40/60. Herschel-Bulkley model was found to explain the flow behavior of all dough formulations. The power-law index (n) of dough samples at 25 °C ranged from 0.52 to 0.87, the consistency index (K) of the samples ranged from 3.6 to 79 Pa sⁿ and the yield stress of the samples ranged from 4.8 to 85.9 Pa. The breads prepared with chestnut/rice flour ratio of 30/70 and containing xanthan-guar blend and emulsifier, had higher quality in terms of hardness, specific volume, color and sensory values. However, elevated levels of chestnut flour led to some deterioration in quality parameters (low volume, harder texture and darker color) regardless of gum blend and emulsifier addition.     

Incorporation of several additives into gluten free breads: Effect on dough properties and bread quality

The objective of this work was to assess the effect of emulsifiers, hydrocolloids and enzymes on gluten-free dough rheology and thermal properties and bread quality, while relating dough properties parameters to bread technological quality. Breads were based on rice flour, cassava starch and full-fat active soy flour, with 65% or 75% (flour-starch basis) of water incorporation. Additives used were emulsifiers (diacetyl tartaric acid ester of monoglycerides – DATEM and sodium stearoyl lactylate – SSL), enzymes (glucose oxidase and α-amylase) and hydrocolloids (xanthan gum, carboxymethylcellulose, alginate and carrageenan). Results showed that additive incorporation modified dough behavior, evidenced by different calorimetric and rheological properties. Besides, the electrophoretic pattern of dough extracted proteins changed with glucose oxidase addition. These modifications resulted in breads with different characteristics, such as specific volume, firmness and firming rate, and crumb structure. Nonetheless, they did not necessarily show better quality parameters than the control bread. The control dough displayed good performance for obtaining gluten-free breads of acceptable volume, crumb structure and, principally, with lower hardening rate during storage. Contrary to widespread opinion, this work shows that the presence of additives is not essential for gluten-free bread production. This fact provides new perspectives to the gluten free market at the moment of selecting raw materials and technological parameters, reducing production costs and facilitating gluten free products development.     

Effects of different emulsifier types,fat contents,and gum types on retardation of staling of microwave-baked cakes

The effects of different types of emulsifiers, gums, and fat contents on the retardation of staling of microwave-baked cakes were investigated. First, different types of emulsifiers (DATEM, Lecigran, and Purawave) at three different fat contents (50%, 25%, and 0%) were added to cake formulations to retard staling of microwave-baked cakes. Then, three types of gums (guar gum, xanthan gum, and methylcellulose) were added to the optimum formulations chosen. As a control, cakes formulated without any emulsifier or gum addition and baked in an conventional oven at 175 degrees C for 25 min was used. Weight loss, firmness, soluble starch and amylose content of the cakes were used as the indicators of staling criteria. Cakes were baked in a microwave oven for 1.5 min at 100% power. Variation of staling parameters during storage of cakes followed zero-order kinetics. Use of emulsifiers and gums helped to retard staling of microwave-baked cakes. Fat content was found to be a significant factor in affecting variation of firmness and weight loss of the cakes during storage. DATEM and Purawave were the most effective emulsifier types. Using gums in combination with emulsifiers gave better moisture retention and softer cakes than using gums alone.     

Effects of different emulsifier types,fat contents,and gum types on retardation of staling of microwave‐baked cakes

The effects of different types of emulsifiers, gums, and fat contents on the retardation of staling of microwave‐baked cakes were investigated. First, different types of emulsifiers (DATEM, Lecigran, and Purawave) at three different fat contents (50%, 25%, and 0%) were added to cake formulations to retard staling of microwave‐baked cakes. Then, three types of gums (guar gum, xanthan gum, and methylcellulose) were added to the optimum formulations chosen. As a control, cakes formulated without any emulsifier or gum addition and baked in an conventional oven at 175°C for 25 min was used. Weight loss, firmness, soluble starch and amylose content of the cakes were used as the indicators of staling criteria. Cakes were baked in a microwave oven for 1.5 min at 100% power. Variation of staling parameters during storage of cakes followed zero‐order kinetics. Use of emulsifiers and gums helped to retard staling of microwave‐baked cakes. Fat content was found to be a significant factor in affecting variation of firmness and weight loss of the cakes during storage. DATEM and Purawave were the most effective emulsifier types. Using gums in combination with emulsifiers gave better moisture retention and softer cakes than using gums alone.     

Quantitative analysis of macro and micro-structure of gluten-free rice cakes containing different types of gums baked in different ovens

The effects of different gums on macro-structure of gluten-free rice cakes baked in conventional and infrared–microwave (IR–MW) combination ovens were investigated by using the images obtained by scanner and scanning electron microscopy in this study. The gum types used were xanthan, guar, locust bean, κ-carrageenan and xanthan–guar blend. Cake containing no gum was used as control. It was observed that both addition of different types of gums affected the pore area fraction and percent number of pores of the rice cakes. The highest pore area fraction was obtained in cakes containing xanthan and xanthan–guar blend. Cakes baked in IR–MW combination oven had higher porosity than those baked in conventional oven. Micro-structure of gluten-free rice cakes was also analyzed. According to these results, conventionally baked cakes showed more starch granule deformations. Both granular starch residues and deformed starch structure were observed together in cakes baked in IR–MW combination oven. All of the starch granules did not lose their identity and did not disintegrate completely.     

Assessment of proofing of bread dough in the microwave oven

 The effects of different proofing times in the microwave oven on the quality of microwave baked breads were investigated. The proofing height of the dough, specific volume and the firmness of the breads were found to be dependent on proofing time. When emulsifiers were added, the optimum proofing condition in the microwave oven was found to be 6 minutes at 10% power. The effects of different emulsifiers on the properties of the dough and, the volume and the firmness of the microwave-baked breads were compared. DATEM, Lecimulthin M-45 and Purawave were the three emulsifiers used. Purawave was found to be the most effective emulsifier on bread quality. Received: 5 July 2000 / Revised version: 6 September 2000     

Image Analysis of Gluten-free Breads Prepared with Chestnut and Rice Flour and Baked in Different Ovens

In this study, the effects of chestnut flour and xanthan–guar gum blend–emulsifier DATEM mixture addition on macro- and microstructure of rice breads baked in conventional and infrared–microwave combination ovens were investigated by using the images obtained by a scanner and scanning electron microscopy (SEM). Pore area fraction, pore size distribution, and roundness values of pores were determined. The highest pore area fraction values were obtained in breads prepared by replacement of 46 % of rice flour with chestnut flour containing xanthan–guar gum blend–DATEM mixture and baked in an infrared–microwave combination oven. On the other hand, rice breads containing no additives or chestnut flour had the lowest pore area fraction values. Infrared–microwave combination baking increased both pore area fraction values and total number of pores. Infrared–microwave combination baking caused approximately 23–28 % increase in number of the small pores (0–5 mm²) in rice breads and 71 % increase in number of the large pores (>10 mm²) in chestnut–rice breads. The fiber content and larger starch granules of chestnut flour contributed towards the stabilization of gas bubbles resulting in better crumb structure. More homogenous pore distributions were observed when additives and an infrared–microwave combination oven were used. When microstructure of gluten-free breads was investigated, it was seen that starch granules in chestnut–rice breads baked in an infrared–microwave combination oven did not disintegrate completely.     

EFFECT OF SURFACTANT GEL AND GUM COMBINATIONS ON DOUGH RHEOLOGICAL CHARACTERISTICS AND QUALITY OF BREAD

Sodium stearoyl‐2‐lactylate (SSL), diacetyl tartaric acid esters of monoglyceride (DATEM), glycerol monostearate (GMS) and distilled glycerol monostearate (DGMS) surfactant gels were made with water. Addition of surfactant gels decreased water absorption by the bread while xanthan, karaya, guar and locust bean gums increased the same. Only DGMS or GMS and gum combinations further improved water absorption. All the gums except for guar along with surfactant gels improved dough stability. Both surfactant gels and gums improved the extensograph dough properties of wheat flour to varying degrees. Alveograph characteristics of wheat flour improved to varying extents with surfactant gels while the gums influenced the viscoelastic properties in differing ways. Different combinations of surfactant gels and gums showed varied influences on rapid visco analyzer characteristics of wheat flour. Both surfactant gels and gums improved the bread making quality. Among surfactants, SSL in combination with gums, and among gums locust bean in combination with surfactant gels improved the bread making quality of wheat flour to a maximum extent.     

A Study on Staling Characteristics of Gluten-Free Breads Prepared with Chestnut and Rice Flours

The effects of chestnut flour and a xanthan–guar gum blend–DATEM mixture on staling of gluten-free rice breads baked in conventional and infrared–microwave combination ovens were studied. Staling properties of the bread were assessed using mechanical compression (TA), differential scanning calorimetry, X-ray diffraction, and fourier transform infrared spectroscopy (FT-IR). Hardness, moisture loss, and retrogradation enthalpy values for all bread samples increased significantly during storage. FT-IR spectra showed that the integrated area of peaks around 1,041 and 1,150 cm^?1 wave lengths, which are related to the structure of starch retrogradation, increased with storage time. The X-ray diffractograms of aged breads indicated a B-type structure with the appearance of peaks at around 17°, 19.5°, and 22°. An additional peak at 24° was observed in breads stored for longer periods. Higher values of hardness and lower moisture contents were obtained for breads baked in an infrared–microwave combination oven, but the use of infrared–microwave combination oven did not result in excessive hardness after storage. Retrogradation enthalpies and total crystallinity values of breads did not show significant differences with baking type.The replacement of rice flour with chestnut flour and addition of xanthan–guar gum blend–DATEM mixture in formulations significantly delayed staling of gluten-free breads by decreasing moisture loss, hardness, retrogradation enthalpy, and total mass crystallinity.     

Optimisation of formulations and infrared–microwave combination baking conditions of chestnut–rice breads

The main objective of this study was to design gluten‐free breads containing chestnut and rice flour and xanthan–guar gum blend to be baked in infrared–microwave combination oven. Response surface methodology (RSM) was used to optimise gluten‐free bread formulations and processing conditions. Weight loss, firmness, specific volume and colour change of the breads were determined. Rice flour mixed with different proportions of chestnut flour and different emulsifier contents were used to prepare breads. The gluten‐free formulations were baked using different upper halogen lamp powers, microwave powers and baking time which were varied from 40% to 80%, 30% to 70% and 9 to 17 min, respectively. Gluten‐free breads and wheat breads baked in conventional oven were used for comparison. Breads containing 46.5% chestnut flour and 0.62% emulsifier and baked using 40% infrared and 30% microwave power for 9 min had statistically comparable quality with conventionally baked ones.     

Exploring the applicability of tamarind gum for making gluten-free rice bread

The present study explored the applicability of tamarind gum in making gluten-free rice bread. Hydration properties of gums and pasting properties of rice flour with the gums were analyzed with Rapid ViscoAnalyzer. Batter properties and bread quality characteristics of rice bread containing gums were analyzed. Except for guar and xanthan gum, the final viscosity after hydration of other gums and the pasting properties of rice flour with the gums were similar. The batter properties and the quality of rice bread containing tamarind gum were equivalent or superior to those containing other gums. Cross-sections of rice bread showed that addition of tamarind gum and pectin resulted in a fine appearance, but pectin may not be preferred due to its lower pH causing unpleasant sour taste and smell of the rice bread containing the gum. Therefore, tamarind gum can be a useful gum for applying to make gluten-free rice bread.     

A study on the effects of different gums on dielectric properties and quality of breads baked in infrared-microwave combination oven

In this study, the effects of different gums on dielectric properties of doughs and breads baked in infrared-microwave combination oven were investigated. In addition, the quality parameters of breads formulated with different gums baked in infrared-microwave combination oven were determined. The gums used were xanthan, guar, xanthan-guar blend and κ-carrageenan. The gums were added to the formulation at 0.5% concentration. The dielectric properties and quality parameters of breads baked in infrared-microwave combination oven were found to be dependent on gum type. κ-carrageenan resulted in undesirable final bread quality, while xanthan-guar blend addition improved bread quality (high specific volume and porosity, low hardness values). The dielectric properties of bread samples formulated with κ-carrageenan were found to be the highest among the other gum types.     

A comparative study of the effects of three galactomannans on the functionality of extruded pea–rice blends

The present study evaluated the effects of three galactomannans on the physical and nutritional characteristics, and sensory acceptability of pea–rice based extruded products, targeted as nutritional snacks. A base blend of 70:30 pea and rice fortified with guar gum (GG), locust bean gum (LBG) and fenugreek gum (FG), at 5%, 10%, 15% and 20%, was extruded at pre-determined optimum processing conditions. All three gums resulted in good expanded products. Increasing the inclusion levels of gums, however, had no effect (P > 0.05) on the degree of expansion. Addition of 5% GG and LBG reduced (P < 0.05) the hardness, while the inclusion of GG and LBG at levels higher than 5%, and all inclusion levels of FG, increased (P < 0.05) the hardness of extruded products. Relative to other treatments, FG produced extrudates that were harder and crispier. The mean scores of sensory evaluation indicated that all products containing gums up to 15% were within the acceptable range. Extrusion increased (P < 0.001) the soluble fibre content and decreased the insoluble fraction; the magnitude of these changes were greater in GG and FG. The addition of 15% gums in the pea–rice blend reduced (P < 0.05) the glycaemic index to less than 55. Overall, the data suggest that all three galactomannans could be incorporated up to 15% in a pea–rice blend to develop nutritious, organoleptically acceptable, extruded snack products with low glycaemic index.     

Emulsifiers: Effects on Quality of Fibre-Enriched Wheat Bread

Resistant starch (RS) is a nutritional ingredient commonly used in bread products as dietary fibre (DF). This ingredient presents similar physiological functions than those imparted by DF, promoting beneficial effects such as the reduction of cholesterol and/or glucose levels on blood. Quality improvement of bread containing RS, with an optimized combination of emulsifiers, will be useful in the development of new and healthy bakery products. The objective of this research was to analyse the effects of different emulsifiers on several quality parameters of dough and bread prepared with wheat flour partially substituted with resistant starch as a dietary fibre. A blend of wheat flour/maize-resistant starch (MRS; 87.5:12.5) with sodium chloride, ascorbic acid, α-amylase, compressed yeast and water was utilized. Emulsifiers were incorporated to formulations in different levels according to a simplex centroid design. The viscoelastic, textural and extensional properties of dough were analysed. Bread quality was evaluated throughout the gelatinization and retrogradation of starch, specific volume of loaves, and texture and firmness of bread crumb. The incorporation of 12.5% (w/w) of MRS to wheat flour caused an increase of 5% in water absorption. Stability decreases markedly (from 9.9 to 2.2 min) and the mixing tolerance index increased (from 79 to 35 UF). The sodium stearoyl lactylate (SSL)–diacetyl tartaric acid esters of monoglycerides (DATEM) mixture increased hardness and resistance to extension on dough, whilst dough containing Polysorbate 80 (PS80) was softer; nevertheless, both types of dough retained less CO₂. An optimized concentration of the three emulsifiers (0.24% SSL, 0.18% PS80, 0.08% DATEM, w/w) was obtained by surface response methodology. The bread prepared with this combination of emulsifiers presented a considerable specific volume with a very soft crumb.     

GUAR AND LOCUST BEAN GUMS AS PARTIAL REPLACERS OF ALL-PURPOSE FLOUR IN BREAD: AN OBJECTIVE AND SENSORY EVALUATION

All purpose flour was partially replaced with locust bean (LBG) and guar gums at 0% (control), 2% and 4% replacement levels in a bread product. All bread treatments were evaluated objectively and subjectively. Two percent LBG replacement significantly increased standing height. Firmness of bread was significantly firmer. Crumb color was not significantly different for any of the 5 bread treatments. Crust color was not significantly different for any of the 5 bread treatments. Crust color, however, was significantly lighter for the control in comparison with the 2% and 4% guar and 4% LBG breads. Two percent guar produced a more even cell size distribution throughout the bread crumb. For all 5 bread formulations moistures were not significantly different. Sensory evaluation revealed a significant difference between the control and 4% LBG. Neither the control nor 4% LBG breads were not significantly preferred. Both gums were found to retard bread staling; 2% LBG was the most effective.     

The use of guar and xanthan gums in the production of 'light' low fat cakes

The objective of this work was to develop low fat or light cakes by substituting the fat with either guar or xanthan gums. In order to measure the effect of this substitution, the following were evaluated: specific density of the dough, specific volume, moisture content, internal characteristics and the presence of moulds. Cakes with 25 and 50% substitution of the fat were also evaluated with respect to water activity (A_w), firmness and elasticity. The proximate composition analysis was used to determine the reductions in fat content and caloric value. Cakes with 50% substitution with guar and xanthan gums, up to 15 days storage, showed no significant difference (P < 0.05) with respect to firmness and elasticity. Therefore substitution of 50% of the normal fat content with gums allowed the production of cakes that were light with respect to their fat content. It was found that those made with xanthan gum were considered better with respect to overall appreciation and texture in the acceptability test.     

Evaluation of viscoelastic properties and air-bubble structure of bread containing gelatinized rice

The impact of addition of gelatinized rice porridge to bread has been investigated on loaf volume, viscoelastic properties and air-bubble structure. We prepared four variety of bread: bread containing rice porridge (rice porridge bread), bread containing gelatinized rice flour (gelatinized rice flour bread), and wheat flour and rice flour breads for references. Instrumental analyses the bread samples were carried out by volume measurement of loaf samples, creep test and digital image analysis of crumb samples. Rice porridge bread showed the maximum specific volume of 4.51 cm³/g, and even gelatinized rice flour bread showed 4.30 cm³/g, which was larger than the reference bread samples (wheat and rice flour breads). The values of viscoelastic moduli of gelatinized rice flour bread and rice porridge bread were significantly smaller (p < 0.05) than those of wheat flour and rice flour breads, which indicates addition of gelatinized rice flour or rice porridge to bread dough encouraged breads softer. Bubble parameters such as mean air- bubble area, number of air-bubble, air-bubble area ratio (ratio of bubble area to whole area) were not significantly different among the bread crumb samples. Therefore, the bubble structures of the bread samples seemed to similar, which implied that difference of viscoelasticity was attributed to air-bubble wall (solid phase of bread crumb) rather than air-bubble. This study showed that addition of gelatinized rice to bread dough makes the bread with larger loaf volume and soft texture without additional agents such as gluten.     

Controlling rheology and structure of sweet potato starch noodles with high broccoli powder content by hydrocolloids

Incorporating high volume fractions of broccoli powder in starch noodle dough has a major effect on its shear modulus, as a result of significant swelling of the broccoli particles. Several hydrocolloids with distinct water binding capacity (locust bean gum (LBG), guar gum, konjac glucomannan (KG), hydroxypropyl methylcellulose (HPMC) and xanthan gum), were added to systems with 4 and 20% (v/v dry based) broccoli particles, and the effect of this addition on dough rheology, mechanical properties and structure of cooked noodles was investigated. Hydrocolloids with low (LBG and guar gum) and intermediate (KG) water binding capacity had no significant effect on shear rheology of the dough. Adding hydrocolloids with high water binding capacity (HPMC and xanthan gum) decreased the shear modulus of dough with 20% broccoli particles significantly. CLSM analysis of cooked noodles showed that in samples containing xanthan gum there was also an inhibition of swelling of starch granules. Strength and stiffness of cooked noodles with 20% broccoli particles were higher for samples containing xanthan gum, than samples without xanthan gum. The cooking loss and swelling index of samples with added hydrocolloids were slightly lower than samples without hydrocolloids. Our results showed that hydrocolloids with high water binding capacity can be used to control the degree of swelling of vegetable particles and starch granules in starch noodle products, and thereby control both dough rheology and textural properties of the cooked noodles.     

Effect of common and new gums on the quality,physical, and textural properties of bakery products: A review

Hydrocolloids (gums) have a good functional characteristic such as emulsifying, gelling, solubility, and textural improvement. In the bakery products, hydrocolloids were used to improving dough performance, bread and cake characteristics, sensorial quality, and extension the products shelf life. Several studies reported the potential use of hydrocolloids in breads, biscuits, cakes, and pasta formulation. The present review summarized the effect of the most common and new hydrocolloids (xanthan, guar, Arabic, carrageenan, karaya, alginate, acacia, methylcellulose, carboxy methyl cellulose, hydroxyl propyl methyl cellulose, locust bean, balangu seed, wild sage seed, basil seed, and cress seed gums) on the rheological, physicochemical, textural, and quality characteristics of bakery products. Gums addition improved volume and porosity of the breads and cakes. Gums influence on the gelatinization and retrogradation of starch and decreased the retrogradation of starch. In the bakery products, hydrocolloids were used to improving mixing and increasing the shelf life of the products through moisture preservation and avoidance of syneresis in some frozen foods. This study summarized the influence of the most common and new hydrocolloids on the rheological, physicochemical, textural, and quality characteristics of bakery products. Addition of seeds gum to the breads, biscuits, cakes, and pasta formula led to an increase in the viscosity of the batter. Also, the firmness of bakery products showed that they became softer with increasing gum levels.