Baking Temperature Research Articles

Validation of the RIDASCREEN® Peanut for Determination of Peanut Protein in Cookies, Milk Chocolate, Ice Cream, Trail Mix, Puffed Rice Cereals, and Granola Bar: AOAC Performance Tested MethodSM 112102.

BackgroundRegulations in many countries worldwide prescribe that peanut must be listed on food labels as a cause of food allergies. Re-evaluated voluntary incidental trace allergen labelling (VITAL) values for peanut revealed the eliciting dose (ED01) value—at which 99% of all peanut-allergic individuals will not react—is 0.2 mg peanut protein.ObjectiveValidation of a sandwich ELISA based on monoclonal antibodies to detect peanut proteins.MethodsNon-processed and processed samples are extracted by an easy procedure at 60°C within 10 min. The measurement range is between 0.75 and 6 mg/kg peanut using a national institute of standards and technology (NIST) reference material as calibrator.ResultsThe system shows no cross-reactivity against 91 different food commodities. The LOD was 0.15 mg/kg for food matrixes such as cookies, milk chocolate, ice cream, trail mix, puffed rice cereal, and granola bar. LOQ was verified at a level of 0.75 mg/kg. Recovery studies with incurred milk chocolate and ice cream revealed consistent recoveries between 67 and 85%. Mean recoveries for incurred cookies depend on the baking temperature and time and ranged from 60 to 109%. Repeatability was between 5.2 and 12.3%, whereas relative intermediate precision was between 6.4 and 13.0%. The results for incurred cookies and milk chocolate in the independent laboratory study showed mean recoveries between 99 and 104% with RSDs between 3.56 and 19.5% under repeatability conditions.ConclusionThe results from the in-house validation study and the independent lab confirmed that the method is accurate and in accordance with requirements laid down in Standard Method Performance Requirement 2017.020.HighlightsRIDASCREEN® Peanut quantifies proteins from peanut in a wide range of food categories.

Preparation and characterization of non-crystalline granular starch with low processing viscosity

Non-crystalline granular starch (NCGS) has advantages in the deep processing of starch owing to its unique structure and function. In this study, NCGS was successfully prepared at a baking temperature of 210 °C, and the morphology, structure, pasting properties, and rheological properties of the NCGS were systematically studied. Compared with native starch, NCGS showed a lower processing viscosity and rapid reduction in the peak viscosity from 3795 to 147 cP. Furthermore, NCGS exhibited impaired short- and long-range ordered structures, as indicated by the lower ratio of absorbance at 1047/1015 cm−1 and decreased crystallinity compared to native starch. Additionally, amylose and amylopectin with long and medium chains in NCGS were degraded into short chains, resulting in an increase in amylose content and branch density. The analysis of the physicochemical properties of NCGS, especially the low processing viscosity, is of great importance for the industrial application of starch, particularly in terms of improving the yield, saving energy, and reducing environmental pollution.

Influences of ZnO Nanorod Arrays on Photocatalytic Activity of n-ZnO Nanorods/p-Si Heterostructure

Zinc oxide is known as an excellent material for biosensors, solar cells, semiconductors and photocatalysts. In this work, n-ZnO nanorods/p-Si heterostructures were successfully fabricated by a hydrothermal method at different baking temperatures. The n-ZnO nanorods/p-Si heterostructures show good photocatalytic ability at high baking temperature. The concentration of Rhodamine B can be decreased up to 97% after 150 min treated by the n-ZnO nanorods/p-Si heterostructures grown at 80 oC. This result indicates that the n-ZnO nanorods/p-Si heterostructures are capable of being used in the decomposition of organic compounds.

Optimization of production conditions of biscuit from Musa sapientum flour (‘banane cochon’): Nutritional composition and glycaemic index of the optimized biscuit

Diet management through the consumption of food with recommended nutrient contents but having a low glycaemic index plays an important role in controlling diabetes and its complications. This study aims to develop biscuit from banane cochon flour in order to contribute to the prevention and management of diabetes. The chemical properties and glycaemic index of the ‘ banane cochon ’ were evaluated. This was followed by the optimization of production conditions of biscuits using the central composite design. The responses studied were dry matter, reducing sugar and lipid content. The resulting product was evaluated for its nutritional value and glycaemic index. It resulted that, ‘banane cochon’ has high dietary fibre (12.99%), potassium (1046.14 mg/100g), calcium (512.00 mg/100g), phosphorus (89.90 mg/100g) contents and a low glycaemic index (36.00). The optimum conditions were as thus: 25.81 g (quantity of margarine), 150°C (baking temperature) and 26 min (baking time). This resulted to an optimized biscuit having the following contents: minerals (potassium, magnesium, iron, calcium and phosphorus), dry matter content (95.7%), lipid content (18.71%), reducing sugar (12.01 g/100 g), protein (6.8%), carbohydrate (65.59%), dietary fibre (11.24%), ash content (4.70%) and glycaemic index of 50.77. The results achieved confirmed that Musa sapientum ( ‘banane cochon’ ) flour could be used to obtain a nutritive and a low glycaemic index biscuit. • Nutritional composition, rheological and glycaemic index of Musa sapientum ( banane cochon flour). • Screening of factors influencing the lipid content, dry matter content and reducing sugar content of biscuit from Musa sapientum flour. • Optimization of production conditions of biscuit from Musa sapientum ( banane cochon ) flour. • Nutritional composition and glycaemic index of compromised optimum biscuit form Musa sapientum flour.

Interaction of dough preparation method, green tea extract and baking temperature on the quality of rye bread and acrylamide content

The aim of the study was to determine the impact of three factors: dough preparation method (direct and indirect), green tea extract (GTE) addition (0.1% and 0.5% on flour basis) and baking temperature (230 and 260 °C) on rye bread quality and acrylamide (AA) content. All factors and their interaction had significant influence on quality parameters of dough and bread. pH of dough prepared by direct method was higher. Addition of GTE increased dough TTA, porosity and bread volume and decreased hardness of bread crumb. Breads prepared by indirect method had darker color of crust, which may be due to the higher amount of Maillard reaction products. Acrylamide formation in breads prepared from dough acidified by lactic acid (direct method) was 3.5 times lower than in breads from dough fermented by starter cultures (indirect method). Effect of GTE seemed to be unclear, because in breads made by direct method AA formation was not significantly different, however, in fermented sourdoughs content of this harmful component increased. All of the samples baked in lower temperature (230 °C) contained in average 25% less AA than baked in 260 °C.

Physics in turkey cooking: Revisit the Panofsky formula

Back in 2008, Panofsky gave an empirical formula, T=11.5W2/3, for turkey baking time, T, in hours vs turkey weight, W, in pounds, the so-called Panofsky formula or Panofsky constant. Compared to the previously existed recipes that are based on the simple linear relationship between turkey weight and baking time, the Panofsky formula provides a more accurate estimate for the baking time. For instance, a general guideline of 13–20 min/lb was widely recommended in all previous turkey baking recipes. In this work, we conduct a comprehensive study of the turkey baking process that leads to a mathematical derivation of the Panofsky formula under some approximations. We also generalize the Panofsky formula to define a general Panofsky formula, T=1PW2/3, where P is defined as the Panofsky constant. Under spherical approximations, we then apply an accurate physical solution of the heat transfer equation and use the rigorous solution with numerical methods to study the generalized Panofsky formula and the Panofsky constant. We found that the generalized Panofsky formula can be perfectly applied to all turkey baking scenarios for baking time calculations. Furthermore, we did a careful analysis of the Panofsky constant, which equals 1.5 in the original Panofsky formula. The dependency of the new Panofsky constant on thermal properties of the turkeys and other initial parameters of baking, e.g., initial and final center temperature of the turkeys, oven temperature, thermal conductivity, specific heat, and turkey’s density, was carefully analyzed and mapped out. The Panofsky constant, P, could vary from 1.1 to 1.9 depending on these thermal parameters.

Development of the heat flux instrument using the black body of porous media

The measured accuracy of a heat flux instrument was developed by using the black body of porous media. The SUS 304 stainless wire mesh having PPI (Pores per inch) of 100 and thickness of 0.202 mm constructed by 2 wire-mesh screens was used as the porous media. Three models of a black body of porous media with varying the baking temperature (TH), namely 400, 600 and, 800 °C, were modified at the baking period (tH) of 8 h. As heat sources, four 150 W infrared lamps were used and vertically placed on the instrument’s top. Five levels of electrical voltages (E), including 50, 100, 150, 200, and 250 V, were tested. The instrument’s measured the distance from the infrared lamp (S) was maintained constant at 25 cm. From the experimental results, the radiative heat flux (q̇Exp) was estimated and then were compared to the reliable instrument manufactured by Hukseflux Thermal Sensors (q̇Huk). In order to evaluate the accuracy of the proposed meter, relative error (ERel) was reported. Emissivity coefficient (ɛ) following to the TH, i.e., 400, 600, and 800 °C yielded 0.87, 0.95, and 0.94, respectively. The q̇Exp gave good agreement to q̇Huk at TH of 600 °C and the measurement time (tM) of over 40 s in all experimental ranges of E.

Digital Modeling of Heat Transfer during the Baking Process

Numerical modeling and analysis of the baking process are challenging biochemical processes occurring in bread. These changes result from mass engineering tasks, usually characterized by the complex chain of chemical, physical, and heat transfer processes impacting the baking at the same time primarily caused by a variation of two dominating factors: (i) the heat and (ii) the internal moisture content at different temperatures and during the time’s process. This study presents an analysis of the 1-D computational fluid dynamics model for simultaneous heat transfer within a cylindrical bread sample. The numerical simulations were performed using the finite difference model (FDM) and the finite element model (FEM). In the first case, the proposed numerical model considered radiation and convection during sample heating and described the sample’s simultaneous heat, water, and vapor diffusion mechanisms. The calculations indicated that the FDM was susceptible to the time step; consequently, the range of 10 s and 100 s yielded the only relevant results. In the second case, the FEM was used to describe the phenomena of transportation during baking. Results obtained by the FEM showed a large temperature gradient near the surface. The study showed the presence of some critical cases that are considered the most influential on the stages of bread production. The first critical value is the time when the baking temperature reaches 100° C. The second critical value is the time when the liquid water content in the baking medium reaches its peak. The boundary conditions were examined and illustrated by figures in the center and the surface of the bread.

Low-Temperature Baking Effect of the Radio-Frequency Nb3Sn Thin Film Superconducting CavitySupported by the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2020410), the Major Research Plan of National Natural Science Foundation of China (Grant No. 91426303), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB25000000), and the National Postdoctoral Program for Innovative Talents

The Nb3Sn thin film cavity, having the potential to be operated at a higher temperature and higher gradient compared to the cavity made from bulk niobium, is one of the most promising key technologies for the next-generation radio-frequency superconducting accelerators. In our work, several 1.3 GHz single-cell TESLA-shaped Nb3Sn thin film cavities, coated by the vapor diffusion method, were tested at Peking University and Institute of Modern Physics, Chinese Academy of Sciences. It was observed that the performance of the Nb3Sn thin film cavities in the tests without the slow cooling down procedure and the effective magnetic field shielding was significantly improved by using a low temperature baking at 100 °C for 48 hours. Although the peak electric field of the cavity remained unchanged, the rapid drop of the unloaded Q value (Q 0) with the increasing accelerating field (Q-slope) was effectively eliminated, resulting in an improvement of the Q 0 in the intermediate field region by ∼ 8 times. Furthermore, under better test conditions with the shielded magnetic field less than 5 mG and the slow cooling down procedure in the temperature range of 25–15 K, the Q 0 was still improved by about 20%. Our study shows that the low temperature baking can be an effective supplement to the effective post-treatment for the Nb3Sn thin film cavity.

Preparation of water polyacrylate coated trademark fabrics and its inkjet printing performance

Trademark fabric was prepared with the water polyacrylate as a coating agent and a compound of kaolin and CaCO3 as filler to study the fabric’s digital inkjet printing performance. Results showed that a 7:5 ratio of kaolin and CaCO3 in the fabric produced uneven pores; the best ink absorption, quick-drying performance and the best printing sharpness and the highest colourfastness to crocking. The coating slurry included 100 g water, 25 g EC-507 modified styrene acrylic emulsion, 75 g compound filler (kaolin and CaCO3 according to mass ratio 7:5), 1.5 g dispersant and 0.375 g crosslinking agent. The optimised coating process was a baking temperature of 150 °C and a baking time of 90 s. The fabric was printed upon using an Epson label printer, producing a printing pattern with good printing sharpness (e.g. lines had no bleeding phenomenon, text and patterns were clear, colours were better and printed two-dimensional codes were scannable).

Antioxidative Characteristics and Sensory Acceptability of Bread Substituted with Purple Yam (Dioscorea alata L.).

In this study, plain bread was made by substituting wheat flour with purple yam flour (Dioscorea alata, L). The addition of 0, 10, 15, 20, and 30% purple yam flour aims to increase the functional value of plain bread as a source of natural antioxidants. The bread produced with two baking temperatures (170°C and 180°C) was tested for anthocyanin levels, total phenol, antioxidant activity (DPPH free radical scavenging), volume expansion, color, and preference test. The results showed that the temperatures of the bread baking did not affect anthocyanin levels, total phenol, antioxidant activity, volume expansion, and bread color (p > 0.05). The substitution of purple yam flour had a significant effect on anthocyanin levels, total phenol, antioxidant activity, volume, and bread color (p < 0.05). The levels of anthocyanins, total phenol, antioxidant activity, and darker color increased with the addition of purple yam flower whereas the rate of expansion reduced. However, the addition of purple yam flour did not affect the level of preference for the bread produced. Purple yam flour can be added to the manufacture of bread made from wheat flour as much as 30% with a baking temperature of 180°C. The resulting bread contained total anthocyanins 54.62 mg/100 g db, total phenol 391.14 mg EAG/100 g db, antioxidant activity 48.53% and volume expansion 64.85%, color L∗ = 53.06, a∗ = 6.52, b∗ = 13.32, C = 14.87, H = 64.06, and sensory score = 3.24 (preferred).

Sweet bread chemical properties optimalization based on baking temperature and duration

Bread is main food in several country. Sweet bread is one popular type that has a lasting sweet taste and soft textured with or without stuffing. Baking is the most important process of bread production. The temperature and time required in the baking varies according to the type of bread, big dough, and baking pan in the oven used. This research aimed to identify the optimum level of baking temperature and duration to the chemical properties of sweet bread. Randomized Complete Block Design (RCBD) Factorial with 2 factors and 3 replications were applied for this research. The first factor was baking temperature consisted 4 level (T1= 180 oC, T2= 190 oC, T3= 200 oC, T4= 210 oC), and the second factor was baking duration which composed 4 level (A1= 10 minutes, A2= 15 minutes, A3= 20 minutes, A4= 25 minutes). The results showed that there wasn’t interaction between baking temperature and duration to water content, fat, protein, and carbohydrate, but it was interaction to the ash content. The baking temperature and duration separatelly had significantly effect to the all parameter. The best result according to the SNI 01-3840-1995 was S4W4 (185 oC: 14 minutes) with water content (23.572%), fat (10.906), protein (1.105%), carbohydrate (62.940 %), and ash content (1.736 %).

Nondestructive evaluation of baking parameters on pogácsa texture.

This study aimed to investigate the potential application of image texture processing method on visible crumb structure of salty cake pogácsa, which was prepared with different baking times (5 and 7min) and temperatures (200, 215, and 230°C). For this purpose, changes in gray level co-occurrence matrix (GLCM) features including energy, contrast, correlation, homogeneity, and entropy were monitored and their relationship with the instrumental texture parameters (hardness, adhesiveness, cohesiveness, springiness, gumminess, and chewiness) were assessed. The pore ratios were also extracted and visualized using image processing technique. Texture profile parameters indicated strong correlation (p<.01) with the image pattern parameters in different pogácsa groups. Gumminess showed strong correlation with contrast (0.503), correlation (-0.498), and homogeneity (0.401). Hardness also exhibited correlation with contrast (0.517), entropy (0.341), and correlation (-0.476). The pore ratio showed marked variation in crumb structure when different times and temperatures were used. Baking at 230°C for 7 min maximized the pore ratio (0.56). Penalty analysis revealed that oiliness, pore structure, and color of products were linked with baking time and temperature. Overall, the results suggested that the GLCM-based technique had the potential to be used as a nondestructive method for rapid quality assessment of pogácsa.

Impact of 3D printing and post-processing parameters on shape, texture and microstructure of carrot appetizer cake

How to process novel food with different texture properties and give more space to consumer personalization? These are the main goals of 3D printing: to enable consumers to carefully select their ingredients for healthier meals and create easily complex shapes with specific texture desired. However, only few studies deal with the impact of printing and post-processing parameters on the texture of printed foods. Using a carrot-puree-based dough as a food-ink model, we studied the impact of two printing (nozzle diameter (2.5 to 6.0 mm) and filling rate (40 to 100%)) and two post-processing (time (10 to 30 min) and temperature (120 to 220 °C) of baking) parameters. A Response Surface Design experiment (26 trials) showed the major influence of baking parameters on texture (ex.: crust strength, mean force) and microstructure (total pore area) of 3D-printed cakes. The nozzle diameter impacted their textural properties while the filling rate changed their shape. The optimum printing and post-processing parameters to used are a nozzle diameter of 3.4 mm, a filling rate of 71% and a baking at 177 °C during 25 min. Industrial relevance text3D food printing has a lot of potential to offer foods with specific composition and texture. However, more information is needed about the combined influence of printing and post-processing parameters on texture of 3D-printed foods. In this study, a predictive model was established based on four parameters: nozzle diameter, filling rate, baking time and baking temperature. Statistical analysis also enables a reverse-engineering approach: in the range of texture of the study, knowing the desired texture, we can know the values of printing and post-processing parameters to apply to get the final product. The results of this experimental design and the use of the desirability function will be relevant tools to develop printed cakes with precise textural and microstructural characteristics desired by consumers. This first approach based on instrumental texture study gave us some good keys to continue with sensorial description, as well as visual and sensory appreciation by consumers.

Changes in Microcrystalline Composition, Functional Groups and Combustion Characteristics of Coal in Coalfield Fire Area after Baking by Different Temperature Gradients

ABSTRACT Once fires occur in a coalfield, large quantities of coal in the coalfield will be baked at high temperatures. The changes and differences in the microscopic and spontaneous combustion properties of coals in high-temperature environments (ambient temperature or even after high-temperature baking) in the fire zone have not been studied yet. In this paper, three types of different-rank coals were baked at five different temperatures to investigate their changes in microcrystalline compositions, functional groups and combustion characteristics. The following results were obtained. The temperature treatment causes damage to the microcrystalline structure of different-rank coals. As the baking temperature rises, the aromatic layer spacing decreases, while the ductility and stacking height gradually increase. The aromatic ether content and the aliphatic hydrocarbon content gradually decline, while the -COOH content goes first and then falls. The spontaneous combustion activities of coals around the fire area gradually weaken with the rise of baking temperature. This research is crucial for revealing the effect of temperature, especially fire baking, on the spontaneous combustion characteristics of coal.

Valorization of electric arc furnace slag via carbothermic reduction followed by acid baking – water leaching

The current study is focused on developing a two-step pyro-hydrometallurgical process for the recovery of valuable components of electric arc furnace (EAF) slag produced by the steelmaking industry. The first step (hot step) involves carbothermic reduction of the EAF slag to recover iron along with niobium, chromium, and manganese in a metallic phase and titanium, magnesium, and aluminum in an iron-depleted slag phase. The second step (cold step) involves acid baking – water leaching of the iron-depleted smelting slag to recover these metals in an iron-depleted slag phase. Fractional factorial design of experiment and response surface methodology were utilized to find the optimum operating parameters of the two steps, respectively. The optimum operating conditions were determined to be smelting temperature of 1600 ºC, carbon to slag mass ratio of 0.12 g/gEAFS, and no flux addition for carbothermic reduction and baking temperature of 185 ºC, acid to smelting slag mass ratio of 2.03, baking time of 69.8 min, and water to acid-baked slag ratio of 5.83 for acid baking – water leaching. The metallic phase obtained in the smelting process contains 70.2 wt% iron, 17.3 wt% manganese, 7.0 wt% chromium, and 0.2 wt% niobium. The developed extraction process results in 86.4% titanium and 100% aluminum and magnesium extraction. We expect the findings of this study to help enable the EAF slag valorization using the two-step (hot and cold) pyro-hydrometallurgical process, contributing to sustainable recycling and circular economy.

Flame‐retardant treatment of Lyocell fibers and effects on various fiber properties

SUMMARYHexamethylolmelamine was used as a cross‐linking agent to graft 3‐(dimethylphosphono)‐N‐methylolpropionamide (MDPA) onto Lyocell fibers in a posttreatment process to reduce flammability. The effects of processing conditions on the mechanical properties and P content of the fibers were examined. The results show that increasing the MDPA concentration, microwave treatment time, baking temperature, and baking time increases the P concentration in the fibers, although the mechanical properties of the fibers are reduced to varying degrees. The optimal processing conditions comprise a 40% MDPA concentration, a 320 W microwave treatment for 3 minutes, and baking at 160°C for 5 minutes. Under these conditions, flame‐retardant Lyocell fibers with a breaking strength of 2.47 cN·dtex−1 and a limiting oxygen index of 34.6% were obtained, which meet the performance requirements for textile fibers. Thermogravimetric data indicate that the residual fiber mass after heating increased from 4.7% before treatment to 21.5% after treatment. There was only a minimal change in the hygroscopicity of the treated Lyocell fibers. In addition, after 30 washes, the limiting oxygen index was decreased to 26.5% while maintaining a good flame‐retardant effect.

The Influential Factors of Baking Time in Internal Friction and Bake-Hardening Properties on Low Carbon Steel

This paper aims at exploring the distinctive ways of baking time affecting the hardening degree of the cold-rolled steel. Therefore, with different time span, the annealed sample was baked to test its baking hardening properties. The sample was analyzed micro-structurally after being annealed, pre-deformed and baked. The internal friction was simultaneously measured in terms of different processing conditions during experiments. The following findings are the significant conclusion of the experiments: The important experiment result indicated that when the degree of pre-deformation setting at 5% and the baking temperature at 170°C, the BH value increased but remained unchanged afterwards. Furthermore, when the baking time span was set at 1000 minutes, the BH value reached the maximum but would remain unchanged afterwards. When the degree of pre-deformation was set at 5%, and the baking temperature was set at 17°C with baking time 20 minutes, the SKK peak reached the maximum. When the baking time was 1000 minutes and constantly extended, the height of SKK peak rarely changed. The above experiments are designed to better illustrate and understand the significance of the hardening steel properties for future application in the automobile industry.

Exploring high amylose rice in combination with carboxymethyl cellulose for preparation of low glycemic index gluten-free shelf-stable cookies

PurposeLow glycemic index gluten-free cookies from high amylose rice flour were prepared by modifying baking conditions and ingredient composition.Design/methodology/approachBaking temperature, baking time, and concentration of carboxymethyl cellulose (CMC) were varied between 170 and 190° C, 12–25 min, and 0.2–1%, respectively, using central composite rotatable design. The developed cookies were packed in metalized polyester pouches and stored under ambient conditions for a period of 90 days.FindingsWidth and bulk density of cookies increased significantly (p &lt; 0.05) with an increase in baking temperature, while thickness, baking loss and yield decreased with an increase in baking temperature. Puffiness increased predominantly with the increase in the concentration of CMC. Design expert predicted baking temperature of 185° C, baking time of 22 min, and 0.8% concentration of CMC as desirable conditions for the development of gluten-free cookies from rice flour. Cookies developed after following optimized conditions recorded dietary fiber of 4.66%, resistant starch (RS) content of 7.20% and predicted glycemic index (pGI) of 44.60. RS, pGI, moisture, water activity, free fatty acids and peroxide value increased significantly, whereas hardness and overall acceptability decreased during storage.RPractical implicationsGluten-free (GF) foods are in high demand globally due to the prevalence of celiac disease. Rice lacks gluten protein, and thus, can serve as a potential raw material for the development of GF cookies. In the present study, the ingredient modification and freezing interventions during baking were found to be crucial if the development of low GI gluten-free cookies having good RS content is targeted. Optimized GF cookies prepared via technological intervention and packed in metalized polyester were shelf stable for up to 3 months under ambient conditions. Furthermore, resistant starch content was enhanced while the predicted glycemic index was decreased during storage. Adoption of baking conditions and CMC level optimized in the present study can help to develop shelf-stable GF bakery products for people suffering from comorbidities like celiac disease and diabetes.Originality/valueResistant starch content was enhanced while predicted glycemic index was decreased during storage of gluten-free cookies prepared from high amylose rice flour. The developed cookies can be a complementary diet to people suffering from comorbidities like celiac disease and diabetes.

Effect of Baking Temperature on the Phenolic Content and Antioxidant Activity of Black Corn (Zea mays L.) Bread.

Black corn is known for its health-promoting properties, which are due to its high content of bioactive phytonutrients. However, the high temperatures required during the processing of bakery products usually trigger thermal degradation, and therefore, the loss of all labile bioactive compounds. In the present study, we evaluated the effect of baking temperature on the phenolic content (i.e., TPC, TAC and individual phenolics) and antioxidant activity in black corn (Millo corvo variety) bread. As a result, baking always resulted in a general decrease in TPC, even at 150 °C. In contrast, TAC only decreased when temperatures as high as 180 °C were applied. Some relevant individual phenolics were preserved during the whole process as long as 150 °C was used. In particular, the content of the major anthocyanin, namely, cyanidin-3-O-glucoside, hardly decreased from the raw flour to the final bread. The loss of antioxidant activity of Millo corvo raw flour during bread baking was avoided by heating at 150 °C. These results demonstrate the appropriate temperature to bake Millo corvo corn bread without losing the antioxidant characteristics and health-promoting properties of the starting black corn.