Microwave Baking Research Articles

Dielectric properties, optimum formulation and microwave baking conditions of chickpea cakes.

The aim of this study was to correlate dielectric properties with quality parameters, and to optimize cake formulation and baking conditions by response surface methodology. Weight loss, color, specific volume, hardness and porosity were evaluated. The samples with different DATEM (0.4, 0.8 and 1.2%) and chickpea flour concentrations (30, 40 and 50%) were baked in microwave oven at different power (300, 350, 400W) and baking times (2.50, 3.0, 3.50min). It was found that microwave power showed significant effect on color, while baking time showed effect on weight loss, porosity, hardness, specific volume and dielectric properties. Emulsifier level affected porosity, specific volume and dielectric constant. Chickpea flour level affected porosity, color, hardness and dielectric properties of cakes. The optimum microwave power, baking time, DATEM level and chickpea flour level were found as 400W, 2.84min, 1.2% and 30%, respectively. The comparison between conventionally baked and the microwave baked cakes at optimum points showed that color difference, weight loss, specific volume and porosity values of microwave baked cakes were less than those of conventionally baked cakes, on the other hand, hardness values were higher. Moreover, a negative correlation between dielectric constant and porosity, and weight loss values were detected for microwave baked samples. A negative correlation between dielectric loss factor and porosity was observed. These correlations indicated that quality characteristics of a microwave baked cake sample can be assessed from dielectric properties. These correlations provides understanding on the behavior of food material during microwave processing.

Effect of Microwave Assisted Baking on Quality of Rice Flour Bread

AbstractTo develop gluten free bread, rice flour dough with the addition of whey protein concentrate (WPC, 0–6 g/100 g flour) was baked under three conditions – hot air baking (HA), microwave baking (MW) and microwave‐assisted hot air baking (HA‐MW). An increase in the WPC content increased the volume and the moisture content of the bread (P ≤ 0.05). The MW and HA‐MW methods increased the hardness of bread crumbs and the L* value of the bread crust (P ≤ 0.05). The estimated glycemic index (GI) of the HA bread was 80.34 ± 0.88. With the addition of 6 g WPC/100 g flour, the GI was reduced to 70.46 ± 1.70. By changing from HA to MW, the GI was further reduced to 61.67 ± 0.69. Without the addition of WPC, enthalpy of retrogradation (ΔH) of the freshly baked bread using MW was higher than from HA and HA‐MW. The enthalpy tended to increase with increased storage time.Practical ApplicationsMicrowave could increase the heating rate during baking and affect the protein‐starch matrix in gluten free bread made from rice flour. Consequently, bread made using the microwave baking method has low starch digestibility and a high enthalpy of retrogradation with increased volume. Therefore, MW with the addition of whey protein concentrate is recommended to develop crustless, gluten‐free bread with a reduced glycemic index, which is good for people who suffer from obesity, diabetes and celiac disease.

Physicochemical properties of foal meat as affected by cooking methods

The present study deals with the effect of four different cooking techniques (roasting, grilling, microwave baking and frying with olive oil) on physicochemical parameters (cooking loss, WHC, texture and colour) and lipid oxidation (by TBARS measurement) of foal meat. Thermal treatments induced water loss (P<0.001), being lower in foal steaks cooked in the grill (25.8%) and higher in foal samples cooked in the microwave (39.5%). As it was expected, all the cooking methods increased TBARS index, since high temperature during cooking seems to cause an increase of the lipid oxidation in foal steaks. Statistical analysis displayed that WHC was affected (P<0.001) by thermal treatment, since the smallest WHC values were observed in samples from microwave treatment. Thermal treatment also caused a significant (P<0.001) increase in the force needed to cut the foal steaks. Regarding colour parameter, cooking led to an increase of L*-value (lightness) and b*-value (yellowness), while a*-value (redness) markedly decreased in all samples.

The effect of cooking methods on nutritional value of foal meat

The present study deals with the effect of four different cooking techniques (roasting, grilling, microwave baking and frying with olive oil) on nutritional value (fatty acid, amino acid profile and chemical scores of the essential amino acids) of foal meat from “Galician Mountain” breed (slaughtered at 15 months and with 102.6kg of carcass weight). Cooking treatment decreased (P<0.05) the amount of saturated fatty acids. Fried meat had lower saturated fatty acid content due to the incorporation of mono-unsaturated (C18:1n-9) fatty acids from oil. Statistical analysis displayed that total essential amino acids and non-essential amino acids were no affected by cooking treatment. However, the content of methionine, phenylalanine, hydroxyproline, tyrosine and cysteine increased (P<0.001) and the content of histidine and lysine decreased (P<0.001) with cooking treatments. Finally, chemical scores of the essential amino acids presented differences between raw and cooked samples. Cooking treatment decreased the chemical scores of histidine and lysine, and increased methionine and phenylalanine+tyrosine scores. Heat treatments also increased the essential amino acid index, although the grilled and fried samples showed no significant differences from raw meat. In conclusion, the grilled and roasted would be the best cooking techniques from the nutritional standpoint.

Cooking losses, lipid oxidation and formation of volatile compounds in foal meat as affected by cooking procedure

ABSTRACTThe present study deals with the effect of four different cooking techniques (roasting, grilling, microwave baking and frying with olive oil) on cooking losses, lipid oxidation (by thiobarbituric acid reactive substances (TBARS) measurement) and formation of volatile compounds (using solid‐phase microextraction (SPME) and gas chromatography combined with mass spectrometry (GC–MS)) of foal meat. Statistical analysis displayed significant (P &lt; 0.001) differences on cooking losses by thermal treatment, being lower in foal steaks cooked by grilling (21.1%) and higher in those cooked by microwaving (35.2%). As expected, all the cooking methods increased the TBARS index, because high temperatures during cooking seem to cause an increase of the lipid oxidation in foal steaks, being higher in roasted and microwaved foal meat, followed by grilled and fried cooking. Thermal treatments led to an increase in total volatile compounds (ranging from 734.6 to 955.1 area units (AU) × 106/g dry matter) compared with raw steaks (301.3 AU × 106/g dry matter). As cooking temperature increased, an increase in the formation of volatile compounds and lipid oxidation was observed. The major volatile compounds were aldehydes in cooked samples, whereas in raw steaks they were esters. This indicates that the compounds produced by lipid oxidation have a great influence on the flavour of the cooked meat. Copyright © 2014 John Wiley &amp; Sons, Ltd.

In vivoantioxidant, hypoglycemic, and anti-tumor activities of anthocyanin extracts from purple sweet potato

Anthocyanin from purple sweet potato (PSP) extracted by microwave baking (MB) and acidified electrolyzed water (AEW) exhibited antioxidant activity. After further purification by macroporous AB-8 resin, the color value of PSP anthocyanin (PSPA) reached 30.15 with a total flavonoid concentration of 932.5 mg/g. The purified extracts had more potent antioxidant activities than the crude extracts. After continuously administering the PSP extracts to 12-mo-old mice for 1 mo, the anti-aging index of the experimental group was not significantly different from that of 5-mo-old mice. To a certain degree, PSPA was also effective for controlling plasma glucose levels in male Streptozocin (STZ)-treated diabetic mice. In addition, the extracts inhibited Sarcoma S180 cell growth in ICR mice. Mice consuming the PSP extracts formed significantly fewer and smaller sarcomas than mice consuming the control diets. The highest inhibition rate was 69.03%. These results suggest that anthocyanin extracts from PSP not only exert strong antioxidant effects in vitro, but also had anti-aging, anti-hyperglycemic, and anti-tumor activities.

EFFECT OF COOKING STYLES ON THE LIPID OXIDATION AND FATTY ACID COMPOSITION OF GRASS CARP (CTENOPHARYNYODON IDELLUS) FILLET

ABSTRACT The effects of six cooking styles, including boiling, steaming, microwaving, grilling, pan-frying and deep-frying, on the lipid oxidation and fatty acid composition of grass carp (Ctenopharyngodon idellus) fillets were investigated. All treatments reduced the moisture contents and increased the relative ratio of protein. Compared with raw samples, the proportions of polar lipid fractions of all samples were increased, while free amino acid contents were significantly decreased. Peroxide values decreased during pan-frying and deep-frying, but remained constant in the samples subjected to the other four cooking methods. Microwave baking and grilling increased the p-anisidine values and resulted in higher lipid oxidative extents. Boiling, steaming, microwave baking and grilling did not affect the fatty acid composition. Pan-frying and deep-frying increased the general polyunsaturated fatty acid content and decreased the n–3/n–6 ratio, especially for the deep-frying cooking method. PRACTICAL APPLICATIONS Fish consumption has been linked to health benefits such as reduced risk of coronary heart disease. This is largely attributed to the lipid, cholesterol, fatty acid composition and the polyunsaturated fatty acids present in fish oils. The ω–3 : ω–6 and polyunsaturated fatty acid/saturated fatty acid ratios are considered to be useful criteria for comparing relative nutritional and oxidation values of fish oils. This study was therefore conducted to determine the influence of different cooking styles on the lipid oxidation of grass carp. These features and information are very important to the food health industry because they could be potential guidelines for the clinical, community, foodservice and research dieticians to recommend the proper cooking methods to get better health effects. It is also useful for academic studies on food composition and nutrition.

Effect of Soy Addition on Microwavable Pocket‐Type Flat Doughs

Microwavable frozen baked goods are widely used by the food industry. However, the altered heat and mass transfer patterns associated with microwave radiation result in tough and rubbery baked products due to reduced plasticization of the polymers. Ingredients with high water-holding capacity and high content of polar lipids have been shown to enhance gluten plasticization and to improve water retention. Therefore, this study explored the physicochemical changes imparted by microwave baking of pocket-type flat doughs with and without soy added at 10%, 20%, and 26% and compared these to their conventionally baked counterparts. Microwave baking resulted in a soft, rubbery, and tough wheat product with increased "freezable" water. Soy was added to the formulation as a means to improve polymer plasticization. Conventional baking of soy doughs resulted in rubbery and tough products due to changes in water state and mobility (freezable water approximately 15 compared with 7.09 of the control). However, soy reduced the cohesiveness of the microwave baked products reaching the lowest value at 20% soy addition (cohesiveness 0.33 ± 1, comparable to that of the conventionally baked control). These data suggest that reduction of water mobility induced by soy proteins and polar lipids (confirmed by thermogravimetric analysis [TGA] and ¹H nuclear magnetic resonance [¹H NMR]) possibly plasticized the starch-gluten network of microwave baked soy doughs. Thus, soy was shown to improve the texture of microwave baked pocket-type flat doughs although further formula optimization is warranted. Microwavable pocket-type flat doughs are used frequently by the food industry to enrobe meat, vegetable, and sweet items for convenient meal delivery. Microwave heating of such doughs induces the development of crustless products compared to conventionally baked products, resulting in a tough and rubbery texture. Partial substitution of wheat flour with soy, in the form of soy flour and soy milk powder, prevented the deleterious textural changes associated with microwave heating. These results suggest that soy is a functional ingredient for the textural improvement of microwavable pocket-type flat doughs.

Anthocyanin extracts from purple sweet potato by means of microwave baking and acidified electrolysed water and their antioxidation in vitro

Summary Two anthocyanin extracts from purple sweet potato (PSP) were prepared by means of microwave baking (MB) and acidified electrolysed water (AEW) or 95% ethanol. The extraction yield in AEW (pH 3.0) was up to 35.0% nearly 2.5 times higher than in ethanol. When pH ≤ 3.0, the lower the pH values of the extracts in solution were, the darker the red extracts were. Total flavonoids, phenolic and monomeric anthocyanin contents in AEW extract were 132.13, 64.52 and 102.31 mg g−1, respectively, whose values were the similar to or slightly lower than those in ethanol extract. On the contrary, its total sugar content (61.31 mg g−1) was nearly five times higher than that of the ethanol extract. In vitro assay indicated that the scavenging capability of DPPH free radicals of AEW extracts (IC50 = 12.0 μg mL−1) was stronger than that of the ethanolic ones. The reducing power and inhibiting lipid peroxidation of the two extracts were similar. Thus, the new extraction of MB-AEW described here was not only simple and low in cost, but also had much higher extraction yield. The anthocyanin extracts with a strong antioxidation and a stable red colour could be widely used as food colouring additives and anti-ageing health foods.

Microwave Baking in Food Industry: A Review

Microwave Baking in Food Industry: A Review

Dielectric properties of microwave-baked cake and its constituents over a frequency range of 0.915–2.450 GHz

There is a large market for microwave foods, with one of the most prevalent growth areas being low-density bakery products. The dielectric constant and loss factor of Madeira cake batter and its constituents (sugar, cake concentrate, margarine, flour, egg) were measured at a range of moisture contents (0.429–1.000 kg kg −1, dry basis), temperatures (20–80 °C), and over a frequency range of 915–2450 MHz. In general, for a given material, the dielectric properties of samples increased with increasing frequency. Irrespective of frequency and sample moisture content, the dielectric constant of batter and flour was relatively independent of sample temperature, whereas that of the sugar samples increased with increasing temperature, particularly within the lower moisture range. At 2450 MHz the loss factor of batter and flour samples decreased by a limited amount as temperature was increased, whereas at 915 MHz they were relatively unaffected. The sugar samples showed a significant decrease in loss factor with increasing temperature, irrespective of frequency. During microwave baking, the dielectric properties of Madeira cake batter initially increased sharply and then decreased steadily until the end of the baking process.

Phenolic constituents levels in cv. Agria potato under microwave processing

Phenolic compounds have long been associated with flavour and colour characteristics of fruits and vegetables and actually attract a great interest due to their health protecting properties. In this work, the influence of different power input of microwave baking on the amount of protocatechuic acid ( 1), tryptophan ( 2), chlorogenic acid ( 3), neo-chlorogenic acid ( 4), and cryptochlorogenic acid ( 5) marker compounds left over in peeled and not-peeled potatoes ( Solanum tuberosus L., Agria cultivar) was assessed. A high-performance liquid chromatographic (HPLC) method with diode-array detection (DAD) was used to identify and quantify compounds 1– 5. Other tubers were used to perform analysis of raw potato (control) and traditional baking potatoes products (boiled potatoes). Dielectric behavior of the irradiated tubers was also investigated to emphasize if microwaves treatments are suitable for food processing in terms of nutritional factor preservation. The main results of this work consist on the relevance of the water contents in potato matrixes during the baking processes since these have a crucial role to keep lossy features, to avoid thermal damages and to preserve antioxidant. The best compromise in terms of short baking time and reduced water and phenolic losses is obtained using 500 W as power input.

In vitro Starch Digestibility and Predicted Glycemic Index of Microwaved and Conventionally Baked Pound Cake

The present study compares the effect of baking process (microwave vs conventional oven) on starch bioavailability in fresh pound cake crumbs and in crumbs from pound cake stored for 8 days. Proximal chemical analysis, resistant starch (RS), retrograded starch (RS3) and starch hydrolysis index (HI) were evaluated. The empirical formula suggested by Granfeldt was used to determine the predicted glycemic index (pGI). Pound cake, one of Mexico's major bread products, was selected for analysis because the quality defects often associated with microwave baking might be reduced with the use of high-fat, high-moisture, batted dough. Differences in product moisture, RS and RS3 were observed in fresh microwave-baked and conventionally baked pound cake. RS3 increased significantly in conventionally baked products stored for 8 days at room temperature, whereas no significantly changes in RS3 were observed in the microwaved product. HI values for freshly baked and stored microwaved product were 59 and 62%, respectively (P > 0.05), whereas the HI value for the conventionally baked product decreased significantly after 8 days of storage. A pound cake with the desired HI and GI characteristics might be obtained by adjusting the microwave baking process.

Effect of different cooking methods on the oxidation, proximate and fatty acid composition of silver catfish ( Rhamdia quelen) fillets

The influence of seven cooking methods (boiling, conventional baking, microwave baking, grilling, deep-frying in soybean oil, canola oil, or partially hydrogenated vegetable oil) on the oxidation, proximate and fatty acid composition of silver catfish ( Rhamdia quelen) fillets was evaluated. All the treatments reduced moisture and increased the protein content. The free fatty acid content of the fillets was significantly reduced by the different cooking methods, while conjugated diene levels and peroxide values decreased for all fried samples, but remained constant in the samples subjected to the other cooking methods. Boiling and baking increased thiobarbituric acid reactive substances (TBARS), while grilling and frying did not change TBARS. Boiling, baking, and grilling did not affect the silver catfish fillets fatty acid composition. Frying in canola oil increased n−3/ n−6 ratio, while frying in soybean oil increased the general polyunsaturated fatty acid content, and frying in hydrogenated vegetable oil incorporated trans fatty acids in the fillets.

Comparison of crumb microstructure from pound cakes baked in a microwave or conventional oven

Imaging, light microscopy and scanning electron microscopy were used to compare the microstructure of crumbs from pound cakes baked in a microwave or conventional oven. The microwave baking conditions for pound cake (240 W, 5 min) were established in previous research, conventional baked pound cakes were obtained using a swing oven at 180 °C for 40 min. Statistical differences in total cell, cell/cm 2 and mean cell area ( P⩽0.05) were observed in the image analysis. Cells from microwaved pound cake crumbs were 20% larger. However, factor shape was 0.81 for both microwave and conventionally baked crumbs, and crumbs from both oven types were similar in appearance. Light microscopy revealed birefringence in crumbs from both types of pound cakes. Scanning electron microscopy revealed that the conventionally baked product had a greater amount of protein matrix however; the matrix structure of the crumb was comparable between microwave-baked and conventionally baked pound cakes. In conclusion, our results suggest that the unique aspects of pound cake dough, including its high content of fat, sugar and moisture, make it well suited to microwave baking.

Experimental Study of Microwave Baking of Madeira Cake Batter

Microwave baking characteristics (surface and internal temperature, normalized height, moisture content) of Madeira cake were examined. Cake batter was baked in a bench-scale microwave oven (output power 100–900 W). As a control, an identical sample was baked in a convective oven at 200°C. Microwave baking allowed for up to a 93% reduction in baking time, in comparison with convective baking. The variation in sample centre temperature exhibited two distinct stages; a short ‘warming-up’ period, and a constant temperature (approximately 103°C) stage. A temperature profile through the cake depth revealed that the surface temperature to be lower than the centre. Normalized cake height was observed to increase and then slightly reduce towards the end of baking. A height profile across the sample cross-section revealed the maximum obtainable height was at the sample centre, with the maximum final sample height being achieved using 900 W. The experimental moisture data were adequately quantified in terms of drying constant and moisture diffusivity, both of which increased with power output. Cake baked in the microwave oven at 250 W showed improved textural properties (springiness, moisture content, firmness) as compared to cake baked in the convective oven.

Mathematical modeling of bread baking process

Baking of bread involves temperature, moisture content and volume changes that are strongly coupled. Previous work usually treated these processes separately or semi-empirically, without adequate accounting for the interaction. A model is developed considering heat and moisture transport that is fully coupled with large volume change. Viscoelastic material property is used and is a function of temperature. The model is applied to a conventional baking process and solved using a finite element method. Results from modeling agree with the experimental observations in terms of temperature, moisture, volume changes and surface browning. The model shows that higher than normal baking temperature reduces the baked bread volume. Microwave baking tends to heat the bread from the inside. Therefore, microwave baking, without other special treatment, creates no firm crust and collapsed dough. Sensitivity analyses have been performed for several material properties due to inaccurate or unavailable data for the model. Larger water activity, capillary diffusivity and smaller gas intrinsic permeability tend to over-predict the volume expansion and moisture loss.

Effects of Different Starch Types on Retardation of Staling of Microwave-baked Cakes

Different types of starches (corn, potato, waxy corn, amylomaize and pregelatinized starches) were added to cake formulations to retard staling of microwave-baked cakes. As a control, cake formulated without any starch addition was used. Weight loss, firmness, volume index, specific gravity, soluble starch and amylose content of cakes were used as the indicators of staling and/or quality criteria. Variation of staling parameters during storage of cakes followed zero-order kinetics. Cakes were baked in a microwave oven for 1.5 min at 100% power. Control cakes were also baked in a conventional oven at 175°C for 25 min. Pregelatinized starch helped to decrease moisture loss during baking and storage. Cakes containing amylomaize starch were firmer than the control cake. Starches, except amylomaize, were effective in reducing firmness during storage. The most effective starch type, in terms of retarding the staling of microwave-baked cakes, was chosen as pregelatinized starch. More amylose was leached in control cakes during microwave baking than conventionally baked cakes.

Color and Texture Development During Microwave and Conventional Baking of Breads

The color parameters (L*, a*, and b*) and hardness of breads baked in microwave and conventional ovens were compared. Moreover, the effect of susceptor on color and texture development during microwave baking were studied. Microwave oven was operated at 30 and 40% powers for 3.5–5.5 min with half-minute intervals. Breads were baked in conventional oven at 175°C and 200°C for 10–18 min and at 225°C for 4–12 min with 2 min intervals. It was not possible to obtain sufficient brown color on the surfaces of the breads in microwave baking. Usage of susceptor helped the achievement of brown color on bottom surfaces of breads. Zero order kinetic model was proposed for L* variation of breads during microwave and conventional baking. Hardness of microwave and conventionally baked breads increased during baking. Rates of hardness variation in microwave baked breads were higher than that in conventionally baked breads.

Microwave, infrared and infrared-microwave combination baking of cakes

The objective of the study was to compare the quality of cakes during baking in microwave, infrared (IR) and IR-microwave combination ovens. Quality parameters evaluated were weight loss, specific volume, firmness and colour of cakes. As control, conventionally baked cakes were used. Cakes baked in a microwave oven had the lowest quality. It was possible to achieve surface colour formation in cakes by IR and IR-microwave combination baking. IR-microwave combination baking reduced weight loss and firmness while it increased the volume of microwave baked breads. Halogen lamp-microwave combination oven produced cakes having similar firmness and colour values with conventionally baked ones. The best conditions for baking of cakes in IR-microwave combination oven was 5 min at 70% halogen lamp and at 50% microwave power levels. When an IR-microwave combination oven was used at this condition conventional baking time of cakes was reduced by about 75%.