Bread Surface Research Articles

The potential of UVC decontamination to prolong shelf-life of par-baked bread.

The effect of UVC (254 nm) treatment on the mould-free shelf-life of par-baked wholemeal, rye and six-grain bread was examined. Currently, these breads are par-baked, wrapped in high-density polyethylene (HDPE)-foil and transported or stored at room temperature for a couple of days before being full-baked and sold/consumed. Generally, after five days, these breads show signs of mould spoilage. A shelf-life increase in one or more days would already offer immense economical and logistic benefits for the baker or retailer. In this study, the parameters fluence rate (irradiation intensity), fluence (UV dose), distance to the UV-lamp (DTL) and number of layers of a common wrapping HDPE-foil (20 µm) were diversified. The breads were subjected to a UVC treatment (0-2502 mJ/cm²), packed and stored at room temperature for a period of 15 days (21.5 ± 0.8 °C). Similar as for the breads, agar plates with mould spores of Aspergillus niger, Aspergillus montevidensis and Penicillium roqueforti were UVC treated (0-1664 mJ/cm²) and checked daily for visible mould growth during 15 days (25 °C). Aspergillus niger showed the strongest resistance towards UVC, a fluence of 800 mJ/cm² was needed to inhibit growth during 15 days of storage, whereas for P. roqueforti and A. montevidensis, respectively, UV levels of 291 and 133 mJ/cm² were found sufficient. Furthermore, the shelf-life of wholemeal, rye and six-grain bread can be prolonged from 5 to 6, 8 and 9 days, respectively, using 2502 mJ/cm². The effect of higher UVC dosage on shelf-life reached a maximal level and was strongly impacted by the wide spread on data of mould-free shelf-life. The main factors influencing the potential of UV decontamination were the rough bread surface, differences in DTL, the possibility of post-contamination and UV permeability of packaging materials.

View factor computation and radiation energy analysis in baking oven with obstructions: Analytical and numerical method

AbstractIn a baking oven, radiation heat transfer is the most prevalent mode of heat exchange. In the present investigation, a new baking oven was designed with two hemi cylindrical domes (called reflectors) attached to the heating coils at the top and bottom of the baking oven. Firstly, view factors were computed by finite element and analytical methods with different bread dimensions, as well as with and without the reflectors. The network representative method and S2S method were employed to analyze the radiation energy transfer in the oven at different baking temperatures using the same bread sizes. The results obtained from numerical and analytical methods were fairly similar. The radiative heat energy absorbed by bread surface was higher with the reflector than without the reflector in the oven. As the number of obstructions increased, the radiative heat flux was reduced. The inclusion of reflector shield in oven affect the heat lux on the bread. The radiative heat flux received by bread was found to have increased on increasing the oven temperatures. Moreover, quality parameter such as the color of the bread with and without the reflectors were also examined. The oven reflector had a noticeable effect on the color of the bread (p < 0.05).Practical applicationsIn recent years, reducing energy consumption has become more important in the design of ovens. Although domestic electric ovens are a convenient way to bake quality goods, they have a very significant energy loss. Prior research has focused on CFD modeling for commercial ovens to assess the thermal behavior of the system and overall energy efficiency of baking. Baking ovens operate at higher temperatures, hence, heat transfer by radiation is highly essential. In reality, one or more surfaces in oven are obstructing the surfaces. To calculate view factors and achieve accurate radiative heat transfer in such cases, the shadow effect must be taken into account. To solve them precisely in this situation, numerical techniques are highly beneficial.

Food grade nanoemulsion development to control food spoilage microorganisms on bread surface.

The online version contains supplementary material available at 10.1007/s13197-022-05660-5.

Effect of psyllium husk and wheat mill bran fractions on the microstructure and mixograph characteristics of Arabic bread

When psyllium husk, wheat bran and germ was added, Incorporation of psyllium and wheat bran may affect the dough structure, dough rheology as well as the final quality of baked Arabic flat bread, which, thus, became important for this study. Scanning Electron Micrographs (SEM) taken on Arabic bread, depicted both intact small and the large starch granules on the outer crust area. This was mainly due to the rapid loss of moisture from the Arabic bread surface during intense baking operation leaving less moisture for gelatinization to take place. With psyllium added to WWF at 0, 3, and 5 % level, the peak time was increased from 3 to 4.5 min. The ascending and descending angle values were more or less identical in all the samples except with wheat germ addition, whereas much lower values (51 to 58°) for these parameters were observed, indicating a faster rate of dough breakdown. With psyllium, fine- and coarse bran addition to WWF, a corresponding increase in peak time was observed. Ascending and descending angles showed similar trends to that of the WWF and psyllium combinations. Use of falling number apparatus is an indirect method of measuring the diastatic enzyme activity in cereal flours. WGF showed lower falling-number values (502 s) than the WWF (607 s). Addition of fine bran to WWF lowered the falling number (607 to 563 s) whereas with coarse wheat bran and germ, these values were increased.

The technology of functional rye-wheat bread with oat flour

The technology of functional rye-wheat bread with oat flour is researched in this study. Oat flour has some useful properties. Microbiological analysis of sourdough used in production of rye-wheat bread was conducted. One control sample and five test samples of bread were made. Control sample contains wheat flour, rye flour, salt, yeast, water and sourdough. Test samples contain 3, 5, 7, 10 and 15 % of oat flour as well as wheat and rye flours. Sensory and physical-chemical properties of test samples were determined. Each sample was rated on a five-point scale by five quality indicators which are taste, colour, aroma, texture and bread surface. Specific loaf volume, acidity, moisture content and porosity were determined. It was revealed that along with increasing of oat flour mass, the porosity and specific loaf volume of the bread samples decrease. Acidity and moisture content of control and test samples are the same. The content of nutrients in test samples with oat flour was calculated.

Climate-Changed Wheat: The Effect of Smaller Kernels on the Nutritional Value of Wheat

Through plant breeding and improved agronomy, the average wheat kernel size increased globally by about 40% from 1940 to 2000. Millers demand larger kernels because they contain more white flour (endosperm). Climate pressures are resulting in frequently reduced kernel size and routine rejection by the commodity system. If whole-wheat flour instead of white flour is the target, these smaller kernels have unrealized value. A total of 94% of Americans do not meet the recommended fiber intake, and inadequate fiber intake plays a role in the development of multiple chronic diseases. A total of 98% of the fiber in wheat is found in the bran. Bran content was measured in “big” (x¯ = 0.042 g/kernel) and “small” (x¯ = 0.023 g/kernel) kernels in nine varieties over locations and years. On average, small kernels contained 15.9% more bran than big kernels (n = 54, p < 0.001) and, thus, had higher mineral and fiber content. In the majority of cases, baking showed no difference in whole-wheat quality among flours within the same variety, regardless of kernel size, based on bread slice height and surface area. Wheat that was rejected by commercial mills as too small produced satisfactory bread. Favoring larger kernels and white flour production has unintended health consequences. Valuing smaller kernels and whole-wheat production provides an outlet for farmers dealing with increasing climate pressures and leads to an end-use product which can improve human health by increasing dietary fiber consumption.

Quality of bread from flour of different spelt wheat varieties

Purpose. To study the quality formation in bread from different flour of spelt wheat (premium, whole-wheat) depending on the variety and line.
 Methods. Laboratory, mathematical and statistical, physical and chemical.
 Results. The bread volume made from high-grade flour varied from 303 to 523 cm3, which corresponds to 1.0–7.6 points depending on the variety and line of spelt wheat. The bread volume made from whole-wheat flour was 10–20% less than the bread volume made from premium flour. The average bread volume obtained from whole-wheat flour of ‘Zoria Ukrainy’ variety was 470 cm3, while low bread volume was obtained from flour of ‘Shvedska 1’ variety and LPP 3132, LPP 3117, TV 1100 lines which corresponded to 2.8–3.2 points. In other varieties and lines, these indicators were very low and ranged between 270 and 328 cm3 or less by 142–200 cm3 compared to the standard variety. The convexity of pan bread made from high-grade flour was the highest in ‘Zoria Ukrainy’ spelt wheat variety and NAK 34/12‑2 line: 0.49 and 0.54, respectively, which corresponded to 5.0 points. Significantly higher indicators were found in P 3, NAK34/12–2, and LPP 3122/2 lines: 0.38–0.51 (1.0–5.0 points). In ‘Shvedska 1’ variety and five lines, the indicator of bread convexity varied from 0.27 to 0.37 (from 3.0 to 4.0 points). In other varieties and lines it was significantly lower (0.07–0.21) than in the standard. The indicator of bread convexity from whole-wheat flour in ‘Zoria Ukrainy’ spelt wheat variety was 0.37 which corresponded to 4.0 points. Significantly higher indicators were found in P 3, NAK34/12–2 and LPP 3122/2 lines: 0.38–0.51 (1.0–5.0 points). In ‘Shvedska 1’ variety and five lines, the bread convexity indicator varied from 0.27 to 0.37, that corresponds to 3.0–4.0 points). In other varieties and lines it was significantly lower (0.07–0.21) than in the standard. Culinary quality of bread was high in all samples: 7.2–8.4 points (80–93% of the maximum value). However, the highest quality had the bread made from ‘Zoria Ukrainy’ variety, LPP 3132, NAK34/12–2, and TV 1100 lines. The overall culinary quality of whole-wheat bread was very high as it varied from 8.3 to 9.0 points. However, the bread made from ‘Shvedska 1’ variety and LPP 3117, LPP 3122/2, P 3, LPP 3132, NAK34/12–2 lines had the highest quality (9.0 points).
 Conclusions. Gloss index of bread surface and its overall estimate is affected by the protein content in grain. Gluten content has a slightly smaller effect on bread quality. In addition, crust surface, bread texture, the overall estimate of bread quality is also affected by the gluten deformation index. Bread obtained from ‘Zoria Ukrainy’ flour, LPP 3132, NAK34/12–2, and TV 1100 lines had the highest overall culinary evaluation.

Nutritional Composition, Techno-Functional Properties and Sensory Analysis of Pan Bread Fortified with Kenaf Seeds Dietary Fibre

Kenaf seeds are underutilized source of food with good source of dietary fiber, protein, essential oil, and phytocompounds. The objectives of this study were to determine the nutritional composition of kenaf seeds, the techno-functional properties of kenaf seeds dietary fibre (KSDF), and sensory analysis of pan bread fortified with dietary fibre that was extracted from kenaf seeds. Analyses showed that kenaf seeds are rich in dietary fibre (28.87 g/ 100 g), protein (27.07 g/ 100 g), oil (23.78 g/100 g) and mineral (5.55 g/100 g). The dietary fibre that was extracted through enzymatic hydrolysis (KSDF (EH)) exhibited significantly (p < 0.05) greater water-binding capacity (WBC), oil-binding capacity (OBC) and viscosity than non-enzymatic hydrolyzed kenaf seeds dietary fibre (KSDF (NEH)) and defatted kenaf seed meal (DKSM). Different formulations of bread were prepared by replacing 10% of wheat flour with wheat bran fibre (positive control), rice bran fibre and KSDF, with white bread unfortified with fibre as negative control. Addition of 10% KSDF to bread formulation significantly (p < 0.05) reduced bread height, volume, specific volume, water activity and firmness, and increased proofing time and bread surface colour. Results from the sensory evaluation of the bread samples also showed that KSDF bread was the most acceptable in comparison to rice bran and wheat bran fortified breads. This study shows that kenaf seed has valuable source of dietary fibre with the potential to be used as a functional ingredient in the development of functional breads.

Technology of functional bread using buckwheat flour

Buckwheat flour contains valuable protein, flavonoids, rutin. It is characterized by proper balance of nutrients. It was revealed that the most common sources of functional ingredients are flour as well as plant raw materials which are added powdered or extracted. Microbiological analysis of sourdough used in production of rye-wheat bread was conducted. One control sample and five test samples of bread were made. Control sample contains wheat flour, rye flour, salt, yeast, water and sourdough. Test samples contain 3, 5, 7, 10 and 15 % of buckwheat flour as well as wheat and rye flours. The content of buckwheat flour was calculated as a percentage of the total mass of flour according to the recipe. Sensory and physical-chemical properties of test samples were determined. Each sample was rated on a five-point scale by five quality indicators which are taste, colour, aroma, texture and bread surface. The average score for each indicator for each sample was not less than 4.5 points. Specific loaf volume, acidity, moisture content and porosity were determined. It was revealed that along with increasing of buckwheat flour mass, the porosity and specific loaf volume of the bread samples decrease. Acidity and moisture content of control and test samples are the same. Content of nutrients in bread sample containing 15 % of buckwheat flour was calculated. Taking into account calculated content and daily intake of nutrients it can be concluded that obtained bread can be regarded as functional which provides the human body with iron.

Evaluación de la estabilidad microbiológica del pan de molde integral mediante el uso de natamicina

En los últimos años existe un interés creciente por ingerir alimentos naturales, es decir, que sean mínimamente procesados. La bioconservación satisface estos requisitos, ya que aprovecha la capacidad de microorganismos reconocidos como seguros (GRAS) y/o de sus metabolitos para inhibir el desarrollo de microorganismos alterantes o patógenos en alimentos. En el sector panadero el principal inconveniente es la conservación del pan luego del horneado, ya que por la composición y la temperatura de almacenamiento son muy propensos al ataque por hongos. La finalidad de la presente investigación fue evaluar la estabilidad microbiológica del pan de molde integral aplicando por aspersión, soluciones de natamicina con diferentes concentraciones de alcohol en la superficie del panificado a 65°C y 30°C. El estudio implicó análisis microbiológicos de mohos y levaduras, determinaciones de humedad y una evaluación sensorial mediante una prueba triangular, con 24 jueces semi entrenados. Se siguieron las metodologías descritas en los métodos de la AOAC e ISO. El análisis de humedad y el recuento de mohos y levaduras muestran que no existen diferencias significativas (P<0.05) entre los tratamientos. En cuanto al análisis sensorial se evidencia que no existen diferencias significativas en el sabor. Estos resultados demuestran que el pan de molde integral mantiene su estabilidad microbiológica durante los 18 días de estudio siendo el uso del bioconservante una respuesta para los consumidores que continuamente buscan productos más frescos y con menor cantidad de aditivos químicos.

Effect of inulin on rheological, textural, and structural properties of brown wheat flour dough and in vitro digestibility of developed Arabic bread.

The brown wheat flour (BWF)-based Arabic bread was fortified with chicory-derived inulin. The objective of this work was to assess the influence of the inulin concentration (1.25 to 5%) on the rheological, textural properties, and fermentation efficacy of enriched BWF dough. Farinographic measurement established that only 3.75% BWF can be substituted by inulin in a dough formulation, which resulted in lowering the water absorption capacity. The peak gelatinization temperature, Tp detected at 74.4 °C by rheometric measurement, which increased linearly with increasing the inulin concentration. The elastic modulus (G'), however, differed significantly among doughs with the addition of inulin. The dough hardness and compressibility increased as a function of inulin concentration. TPA measurement indicated that the Arabic bread fortified with 3.75% inulin was the best in texture. The addition of inulin improved the volume of CO2 generation in the yeasted dough. The distribution of starch particles on the top layer of bread surface was visualized through SEM. In-vitro digestion and steady-flow measurement of the BWF/inulin bread digesta exhibited a slow digestion and an increment in the apparent viscosity against the control bread, which further confirmed potential health benefits of the developed Arabic bread. PRACTICAL APPLICATION: Arabic bread is a staple food in many Asian countries, and an incorporation of soluble fiber, like inulin, definitely improves its health benefits. This work optimized a formulation based on BWF and inulin with technical feasibility. Rheological and textural studies demonstrated that blend bread could be made by replacing 3.75% BWF by inulin with significantly lower water content. Inulin has replaced the sugar in the yeasted dough, and carried out the bread fermentation adequately.

INVESTIGATION ON QUALITY PROPERTIES OF TRADITIONAL BULK BREAD COVERED WITH PROBIOTICS AND SOYBEAN OIL EDIBLE COATING

Probiotic food products are available at the supermarket commercially, but probiotic bakery products are much less in evidence. In the present study, methyl cellulose (2%), whey protein concentrate (2%), corn starch (1%), and soybean oil at 2, 4, and 6% were used for coating layer on the bulked bread surface, and then the quality properties were studied. The results showed that Lactobacillus rhamnosus GG, as probiotic component of the coating, immobilized in corn starch, whey protein, and methyl cellulose films had enhanced viability throughout shelf-life. The probiotics remained viable for 4 days, maintaining high viable cell number levels. Adding soybean oil at 6% concentration enhanced texture, sensory properties, and image index during storage.

Whey fermented by using Lactobacillus plantarum strains: A promising approach to increase the shelf life of pita bread

Nowadays, there is an increasing concern regarding the shelf life of food products, leading producers to research natural antimicrobial agents to use in food preparation. In this study, we evaluated the antifungal activity of Lactobacillus plantarum fermented whey and then added the whey during preparation of pita bread to study shelf-life improvement. The fermented whey showed a satisfactory inhibitory (antifungal) effect against Penicillium expansum and Penicillium brevicompactum strains: the minimum inhibitory and minimum fungicidal concentrations ranged from 3.9 to 39.0 g/L and from 62.5 to 250 g/L, respectively. Addition of fermented whey increased the shelf life of the pita bread. After inoculation of the bread surface with Penicillium, an increase in shelf life until d 8 was achieved compared with the positive control, whereas under natural contamination conditions, an extension of shelf life until d 19 was observed. In terms of antimicrobial activity, the greatest reduction (100%) in fungal growth was achieved when all of the water in the dough was replaced with fermented whey. An untrained sensory panel could not identify differences between bread produced with fermented whey and control pita breads. These results suggest the possibility of using fermented whey in food preservation.

Rheological properties of toasted bread using a modified American Association of Cereal Chemists method to determine compressive force values

AbstractBackground and objectivesUsing a modified American Association of Cereal Chemists parameter for white bread crumb, CFV20, toasted bread firmness was investigated according to color changes on the surface of toasted bread.FindingsThe L* value decreased significantly with toasting level, compared with changes in both a* and b*. To characterize the relationship between color and the rheological properties of the bread surface, a rheological parameter for bread surface was proposed, Sin, which represents the slope of the force plotted against the plunger distance at a depth of <1 mm below the surface of the bread. The Sin value of the toasted bread corresponded well with toasting level and CFV20 when toasted at low levels, suggesting that the surface firmness reflects the inner firmness of the toasted bread. A tactility sensory evaluation also supported the change in the CFV20 of toasted bread. In addition, the sensory evaluation values did not seem to be intimately influenced by the panel number, at least between n = 5 and n = 12. The rheological property CFV20 increased with decreasing L*. Therefore, L* seems to be a simple tool for measuring the rheological properties of the inner toasted bread.ConclusionsColor determination using the L* value of the toasted bread surface can be used to estimate the inner firmness of the bread.Significance and noveltyThe texture of toasted bread has not been reported. The parameter Sin was proposed as a rheological parameter representing the surface of toasted bread. The firmness of toasted bread according to the change in surface color was investigated in this study.

Application of antifungal lactobacilli in combination with coatings based on apple processing by-products as a bio-preservative in wheat bread production.

In this study various coatings from apple press cake (AP) with immobilized antifungal bacterial cells were used for bread surface treatment to increase anti-moulding effect. The antifungal effect and technological properties of newly isolated Lactobacillus coryniformis LUHS71, L. curvatus LUHS51, L. farraginis LUHS206 and Leuconostoc mesenteroides LUHS225 strains. Then, thelactobacilli were tested for the effects of incorporation ofsourdough on acrylamide formation in bread and antifungal effect against moulds commonly associated with bread spoilage. The addition of 15-20% of sourdoughs significantly (p = 0.0001) improved bread volume and crumb porosity depending on LAB strain, and reduced acrylamide formation on average by 23% (for LUHS51 and LUHS206) by 54% (for LUHS71 and LUHS225) compared to control bread. Additionally, the use of AP-LAB coatings prolonged shelf life from 3 to 6days for control bread, and up to 9days for sourdough breads. The combination of antifungal LAB sourdough and the AP-LAB coating leads to produce high quality bread with extended shelf life and would be a new and promising environmentally-friendly technological alternative.

A concept of mould spoilage prevention and acrylamide reduction in wheat bread: Application of lactobacilli in combination with a cranberry coating

The current study evaluated the technological and antifungal properties of the newly isolated lactic acid bacteria (LAB) strains (P. pentosaceus LUHS183, P. acidilactici LUHS29, Lactobacillus paracasei LUHS244, Lactobacillus brevis LUHS173, Lactobacillus plantarum LUHS135 and Leuconostoc mesenteroides LUHS242) and determined the influence of different LAB sourdoughs and their quantities (10, 15 and 20%) on wheat bread quality, including acrylamide content. In order to prolong the final products shelf life, LAB fermentation was combined with coating of the bread surface using cranberry preparations. All the tested LAB strains showed antifungal activities against Aspergillus nidulans, Penicillium funiculosum and Fusarium poae. L. brevis LUHS173 and Leu. mesenteroides LUHS242 strains showed weak antifungal activities, but good technological and acrylamide-lowering properties (the lowest acrylamide content (5.21 μg kg−1) in bread with 20% of LUHS173 sourdough was achieved). However, by increasing the sourdough content, the bread quality decreased (except Leu. mesenteroides LUHS242), therefore, additional experiments were undertaken, using a cranberries-based bread surface coating. This approach showed antifungal activities against Aspergillus fischeri, Penicillium oxalicum, P. funiculosum, F. poae, Alternaria alternata and Fusarium graminearum. Finally, selected LAB, in combination with an antimicrobial coating, leads to wheat bread with improved quality, safety and extended shelf life.

ANALYSIS OF BAKERY PROPERTIES OF GRAIN OF NEW VARIETIES AND LINES OF WHEAT SPELTS

There were studied technological properties of grain of different varieties and lines of wheat spelt. There were analyzed differences between the quality of bread of flour of the highest sort and wholemeal, demonstrated the topicality of the differentiated approach to technological properties of flour for its production, elucidated the possibility of using wholemeal of wheat spelt for producing bread of the increased biological value. It was experimentally confirmed that a value of gloss of the bread surface and its general assessment is influenced by the protein content in grain. The gluten content influences bread quality parameters a bit less. At the same time, the index of gluten deformation also influences the crust surface, size of pores, general assessment of the bread quality. Its quality is high in all studied samples. The highest general culinary mark is put to bread, obtained from flour of the variety Zorya of Ukraine, LPP 3132, lines NAK34/12-2 and TV 1100. Based on studied of organoleptic, physical-chemical parameters of bread, there was confirmed the possibility of the promising use of wheat spelt grain in the bakery technology for raising the quality of products and widening the assortment.

Elucidation of the mechanism that forms breadbaking properties of the spelt grain

The technology of making dough from spelt flour differs from that known for flour of soft wheat in which starch grains are firmly bound to the protein matrix. It has been established that the content of protein in spelt grain varied from 15.0 % to 22.5 % for varieties and from 14.0 % to 19.8 % for lines. The content of gluten does not depend on the origin of varieties and lines. It amounted to 31.6‒44.9 % in the grain of varieties and 29.2‒43.6 % in the grain of lines. Technological properties of grain of introgressive lines are similar to those of grain of interspecies spelt lines. Index of gluten deformation of grain of spelt varieties and lines varied from 97 to 116 points and the fall number varied from 389 to 416 s. The spelt baking properties differ from those of soft wheat since the maximum gas-holding capacity of dough prepared of spelt flour comes after 60‒90 min of fermentation and then rapidly decreases. The highest stability during fermentation had dough prepared of flour of Zoria Ukrainy variety and NSS 6/01 and NAK34/12-2 lines. Volume of the bread baked of prime flour was from 303 to 523 cm3, which corresponded to 1.0‒7.6 points. The corresponding figure for dark flour was from 270 to 470 cm3 depending on spelt variety and line. Its quality was high in all samples: 7.2‒8.4 points or 80‒93 % of the maximum value. The bread baked of flour of Zoria Ukrainy variety and LPP 3132, NAK34/12-2 and TV 1100 lines was of the highest quality. The overall estimate of quality of the bread baked of dark flour was very high (8.3‒9.0 points) while the bread baked of flour of Swedish 1 variety and LPP 3117, LPP 3122/2, P 3, LPP 3132, NAK34/12-2 lines had the highest quality (9.0 points). Glossiness of the bread surface and its overall estimate were influenced by the content of protein in grain. Gluten content affected bread quality somewhat less. Gluten deformation index also affected crust surface, pore size and the overall estimate of bread. The bread baked of flour of Zoria Ukrainy variety and LPP 3132, NAK34/12-2 and TV 1100 lines had the highest overall culinary estimate. Technological properties of grain of 16 spelt varieties and lines have been theoretically substantiated and experimentally confirmed. Differences between quality of the bread baked of prime and dark flour were analyzed. Relevance of the differentiated approach to the technological properties of flour for its production was shown. Based on the study of physical-chemical and organoleptic characteristics of bread, promising possibility of its use in the baking technology has been confirmed for expanding assortment of products and improving their quality.

Penicillium expansum Inhibition on Bread by Lemongrass Essential Oil in Vapor Phase

The antimicrobial activity of lemongrass (Cymbopogon citratus) essential oil (EO) in the vapor phase on the growth of Penicillium expansum inoculated on bread was evaluated, followed by a sensory evaluation of the bread's attributes after EO exposure. The lemongrass EO was extracted from dry leaves of lemongrass by microwave-assisted steam distillation. The chemical composition of the lemongrass EO was determined using a gas chromatograph coupled to a mass spectrometer. The refractive index and specific gravity of the EO were also determined. Bread was prepared and baked to reach two water activity levels, 0.86 or 0.94, and then 10 μL of P. expansum spore (106 spores per mL) suspension was inoculated on the bread surface. Concentrations of lemongrass EO were tested from 125 to 4,000 μL/Lair, whereas mold radial growth was measured for 21 days. For sensory evaluation, breads were treated with lemongrass EO vapor at 0, 500, or 1,000 μL/Lair for 48 h and tested by 25 untrained panelists. The EO yield was 1.8%, with similar physical properties to those reported previously. Thirteen compounds were the main components in the EO, with citral being the major compound. P. expansum was inhibited for 21 days at 20°C with 750 μL of EO/Lair, and its inhibition increased with increasing concentrations of EO. Sensory acceptance of bread exposed to vapor concentrations of 500 or 1,000 μL of EO/Lair or without EO was favorable; similar and no significant differences (P > 0.05) were observed among them.

Prediction of consumer acceptance in some thermoprocessed food by physical measurements and multivariate modeling

Consumer acceptances for French bread, fish bread, and roasted coffees were calibrated against physical measurements of those products using Multiple Linear Regression. The models obtained were then validated and tested using the widespread used methods of cross-validation, y-randomization and external validation. In all cases, multivariate models presented R2 for calibration greater than.9, which was superior to those univariate ones. For the French bread analysis, the multivariate model performed well and the length of the cut on bread surface is the parameter that most strongly influenced this model; on the other hand, a large width of the cut on bread surface would greatly contribute to a lower acceptance. The model for predicting the acceptance of the fish bread also showed a good performance; the bulkier fish breads received a better acceptance. An efficient model was also obtained for the data set of roasted coffee; redder coffees were more accepted. Practical applications A multivariate regression was used in order to predict the consumer acceptance from measurements commonly performed for characterization of food products. Consumer acceptance can be predicted by easy and rapid physical (and/or chemical) measurements using regression models. Once built and validated, the models can be used to predict the consumer acceptance by rapid physical measurements on the products. This approach can be a useful method to be included as a quality control parameter on food industry.